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    Genetic characterization of Chikungunya virus from New Delhi reveal emergence of a new molecular signature in Indian isolates. Shrinet Jatin,Jain Shanu,Sharma Anil,Singh Shashi Shekhar,Mathur Kalika,Rana Vandita,Bhatnagar Raj K,Gupta Bhupendra,Gaind Rajni,Deb Monorama,Sunil Sujatha Virology journal BACKGROUND:Chikungunya (CHIK) is currently endemic in South and Central India and exist as co-infections with dengue in Northern India. In 2010, New Delhi witnessed an outbreak of CHIK in the months October-December. This was the first incidence of a dominant CHIK outbreak in Delhi and prompted us to characterize the Delhi virus strains. We have also investigated the evolution of CHIK spread in India. FINDINGS:Clinical samples were subjected to RT-PCR to detect CHIK viral RNA. The PCR amplified products were sequenced and the resulting sequences were genetically analyzed. Phylogenetic analysis based on partial sequences of the structural proteins E1 and E2 revealed that the viruses in the latest outbreak exhibited ECSA lineage. Two novel mutations, E1 K211E and E2 V264A were observed in all Delhi isolates. In addition, CHIKV sequences from eight states in India were analyzed along with Delhi sequences to map the genetic diversity of CHIKV within the country. Estimates of average evolutionary divergence within states showed varying divergence among the sequences both within the states and between the states. We identified distinct molecular signatures of the different genotypes of CHIKV revealing emergence of a new signature in the New Delhi clade. Statistical analyses and construction of evolutionary path of the virus within the country revealed gradual spread of one specific strain all over the country. CONCLUSION:This study has identified unique mutations in the E1 and E2 genes and has revealed the presence of ancestral CHIKV population with maximum diversity circulating in Maharashtra. The study has further revealed the trend of CHIK spread in India since its first report in 1963 and its subsequent reappearance in 2005. 10.1186/1743-422X-9-100
    Seroprevalence of dengue, chikungunya and Sindbis virus infections in German aid workers. Eisenhut M,Schwarz T F,Hegenscheid B Infection Vector-borne virus infections were studied in 670 German overseas aid workers who had spent an average of 37.7 months in tropical areas of Africa and Asia. Antibodies to dengue viruses (DEN) were detected by indirect immunofluorescence assay in 43/670 (6.4%) aid workers. Of these 43, 41 (95.3%) were also positive for antibodies to dengue by haemagglutination inhibition assay. The highest seroprevalence was in aid workers returning from Thailand (19.4%), Benin (14.8%) and Burkina Faso (9.2%). Antibodies to chikungunya virus (CHIK) were detected in 9/670 (1.3%) aid workers, and the highest seroprevalence to anti-CHIK IgG was in aid workers who had resided in Benin (5.7%) and Thailand (5.5%). Antibodies to Sindbis virus were detected only in 1/670 (0.1%) aid worker who had been to Zambia. Vector-borne virus infections, especially DEN, pose a health risk for aid workers.
    Study of viremic profile in febrile specimens of chikungunya in Bandung, Indonesia. Riswari S F,Ma'roef C N,Djauhari H,Kosasih H,Perkasa A,Yudhaputri F A,Artika I M,Williams M,van der Ven A,Myint K S,Alisjahbana B,Ledermann J P,Powers A M,Jaya U A Journal of clinical virology : the official publication of the Pan American Society for Clinical Virology BACKGROUND:Data regarding the viremia profile of chikungunya virus (CHIKV) infected patients especially during the pre-febrile period is limited. OBJECTIVE:To obtain virological kinetic data on CHIKV infections. STUDY DESIGN:A two-week community observation for dengue transmission was conducted in Bandung, Indonesia, from 2005 to 2009. Acute specimens from non-dengue febrile patients were screened by pan-alphavirus conventional RT-PCR. The positives were confirmed for CHIKV RNA by a specific RT-PCR followed by sequencing. Simultaneously these specimens were also cultured in Vero cells and tested for anti-CHIK IgM MAC-ELISA. All the available serial specimens,including the pre-febrile specimens, from confirmed CHIK cases, were tested by virus isolation, RT-PCR, qRT-PCR, and CHIK IgM ELISA. RESULTS:There were five laboratory confirmed CHIK cases identified and studied. Among these, viremia was determined to extend from as early as 6 days prior to until 13 days post fever onset. Quantitative RT-PCR showed viremia peaked at or near onset of illness. CONCLUSION:In this study, individuals were identified with viremia prior to fever onset and extending beyond the febrile phase. This extended viremic phase has the potential to impact transmission dynamics and thus the public health response to CHIK outbreaks. 10.1016/j.jcv.2015.11.017
    Pan-American League of Associations for Rheumatology-Central American, Caribbean and Andean Rheumatology Association Consensus-Conference Endorsements and Recommendations on the Diagnosis and Treatment of Chikungunya-Related Inflammatory Arthropathies in Latin America. Monge Pablo,Vega José Manuel,Sapag Ana María,Moreno Ilsa,Montúfar Rubén,Khoury Vianna,Camilo Pablo,Rivera Ruddy,Rueda Juan C,Jaramillo-Arroyave Daniel,Londoño John,Del Carmen Ruiz María,Fernández Félix,Quintero Maritza,Fuentes-Silva Yurilis,Aguilar José Luis,Vallejo-Flores Carlos,Caballero-Uribe Carlo V,Sandoval Hugo,Pineda Carlos Journal of clinical rheumatology : practical reports on rheumatic & musculoskeletal diseases BACKGROUND/OBJECTIVE:Although mortality rates related with chikungunya (CHIK) outbreaks in Latin America's (LA's) dengue-endemic rural and new urban regions are low, dealing with symptoms and sequelae can both produce a significant burden of disease and diminish quality of life-from many months to years-after the acute phase of the infection, with a significant impact on public and individual health.The aim of this work was to establish Pan-American League of Associations for Rheumatology-Central American, Caribbean and Andean Rheumatology Association (ACCAR) consensus-conference endorsements and recommendations on the diagnosis and treatment of CHIK-related inflammatory arthropathies transmitted by Aedes aegypti and Aedes albopictus in LA. METHODS:Based on the Consensus Development Conference format, a panel of ACCAR rheumatologist voting members (n = 10) took part in this Pan-American League of Associations for Rheumatology initiative. Experts voted from a previous content analysis of the medical literature on CHIK, 4 subsequent topic conferences, and a workshop. Consensus represents the majority agreement (≥80%) achieved for each recommendation. RESULTS:The experts' panel reached 4 overarching principles: (1) CHIK virus (CHIKV) is a re-emergent virus transmitted by 2 species of mosquitoes: A. aegypti and A. albopictus; (2) CHIKV caused massive outbreaks in LA; (3) chronic CHIKV infection produces an inflammatory joint disease that, in some cases, can last for several months to years, and (4) currently, there are no vaccines or antivirals licensed for CHIKV infections. RECOMMENDATIONS:Pan-American League of Associations for Rheumatology-ACCAR achieved 13 endorsements and recommendations on CHIK categorized in 3 groups: (1) epidemiology and clinical manifestations, (2) diagnosis, and (3) treatment, representing the consensus agreement from the panel's members. 10.1097/RHU.0000000000000868
    Molecular and phylogenetic evidence of chikungunya virus circulating in Assam, India. Dutta Prafulla,Khan Siraj Ahmed,Hazarika Naba Kumar,Chetry Sumi Indian journal of medical microbiology PURPOSE:Northeast Region of India possesses an abundant number of Aedes mosquitoes, the common vector for Dengue and Chikungunya (CHIK). Dengue is reported every year from Assam, but active surveillance for CHIK virus (CHIKV) infection is lacking in this part of India. Therefore, this present study has been undertaken to detect any CHIKV infection during a dengue outbreak in Assam. MATERIALS AND METHODS:A total of 42 dengue negative samples collected from Guwahati were screened for the presence of CHIK IgM antibodies. Further, all the samples were processed for CHIKV RNA detection by reverse transcriptase-polymerase chain reaction (RT-PCR). Phylogenetic analysis was done by Maximum Likelihood method using Kimura-2 parameter model. RESULTS:No IgM positivity was found in the processed samples; however, 7 samples were positive for CHIKV by RT-PCR. Phylogenetic analysis revealed that the circulating CHIKV belonged to Eastern, Central and Southern African genotype. Sequence analysis showed two uniform nucleotide substitutions and very less amino acid substitution. CONCLUSION:Silent existence of CHIKV beside dengue is reported from this study. Therefore, CHIKV diagnosis should be included as a regular practice for active surveillance of the disease and its accomplishment before commencing an outbreak. 10.4103/ijmm.IJMM_16_127
    Detection of Chikungunya Virus in Nepal. Pandey Basu Dev,Neupane Biswas,Pandey Kishor,Tun Mya Myat Ngwe,Morita Kouichi The American journal of tropical medicine and hygiene Chikungunya virus (CHIKV) is an emerging alphaviral disease and a public health problem in South Asia including Nepal in recent years. In this study, sera were collected from patients presenting with fever, headache, muscular pain, fatigue, and joint pain of both upper and lower extremities. A total of 169 serum samples were tested for CHIKV and dengue virus (DENV) by using Immunoglobulin M (IgM) and Immunoglobulin G (IgG) antibody using enzyme-linked immunosorbent assay (ELISA) method during August to November 2013. Results showed that 3.6% and 27.8% samples were positive for CHIKV and DENV IgM positive, respectively. Similarly, results of IgG showed 3.0% samples were positive for CHIKV IgG and 29.0% were for DENV IgG positive. Further, a 50% focal reduction neutralization test (FRNT50) was performed to confirm the presence of CHIKV, which demonstrated that 8.9% of CHIKV IgM and/or IgG ELISA positive possessed neutralizing anti-CHIK antibodies. To our knowledge, this is the first report in which the presence of CHIKV is confirmed in Nepalese patients by FRNT50. Basic scientists and clinicians need to consider CHIKV as a differential diagnosis in febrile Nepalese patients, and policy makers should consider appropriate surveillance and actions for control strategies. 10.4269/ajtmh.15-0092
    [Chikungunya, an emerging viral disease. Proposal of an algorithm for its clinical management]. Palacios-Martínez D,Díaz-Alonso R A,Arce-Segura L J,Díaz-Vera E Semergen Chikungunya fever (CHIK) is an emerging viral disease. It is caused by the Chikungunya virus, an alphavirus from the Togaviridae family. It is transmitted to humans by the bite of infected mosquitoes, mainly Aedes aegypti and Aedes albopictus. They are also involved in the transmission of dengue, malaria, etc. CHIK is now endemic in any region of Africa and Southeast-Asia. Cases of CHIK have been reported in America, the Caribbean, and Europe (France, Italy and Spain). There are reservoirs of these mosquitoes in some regions of Spain (Catalonia, Alicante, Murcia and Balearic islands). CHIK is characterized by a sudden high and debilitating fever, and severe or disabling symmetrical arthralgia. It tends to improve in days or weeks. There are severe and chronic forms of CHIK. There is no specific treatment or prophylaxis for CHIK. An algorithm is proposed for the clinical management of CHIK based in the latest guidelines. 10.1016/j.semerg.2014.08.008
    Improved detection of Zika virus RNA in human and animal specimens by a novel, highly sensitive and specific real-time RT-PCR assay targeting the 5'-untranslated region of Zika virus. Chan Jasper Fuk-Woo,Yip Cyril Chik-Yan,Tee Kah-Meng,Zhu Zheng,Tsang Jessica Oi-Ling,Chik Kenn Ka-Heng,Tsang Terance Gi-Wai,Chan Chris Chung-Sing,Poon Vincent Kwok-Man,Sridhar Siddharth,Yin Feifei,Hung Ivan Fan-Ngai,Chau Sandy Ka-Yee,Zhang Anna Jinxia,Chan Kwok-Hung,Yuen Kwok-Yung Tropical medicine & international health : TM & IH OBJECTIVE AND METHOD:We developed and evaluated five novel real-time RT-PCR assays targeting conserved regions in the 5'-untranslated region (5'-UTR), envelope (E'), non-structural protein 2A (NS2A), NS5 and 3'-UTR of the ZIKV genome. RESULTS:The ZIKV-5'-UTR assay exhibited the lowest in vitro limit of detection (5-10 RNA copies/reaction and 3.0 × 10 plaque-forming units/ml). Compared to the modified version of a widely adopted RT-PCR assay targeting the ZIKV-E gene, the ZIKV-5'-UTR assay showed better sensitivity in human clinical specimens, and representative mouse specimens, including many organs which are known to be involved in human ZIKV infection but difficult to obtain in clinical settings. The ZIKV-5'-UTR assay detected ZIKV RNA in 84/84 (100.0%) ZIKV-E'-positive and an additional 30/296 (10.1%, P < 0.01) ZIKV-E'-negative mouse specimens. The higher sensitivity of the ZIKV-5'-UTR assay was most significant in kidney and testis/epididymis specimens (P < 0.01). No in vitro or in vivo cross-reactivity was found between the ZIKV-5'-UTR assay and dengue virus, yellow fever virus, Japanese encephalitis virus, West Nile virus, hepatitis C virus and Chikungunya virus. CONCLUSIONS:The highly sensitive and specific ZIKV-5'-UTR assay may help to improve the laboratory diagnosis of ZIKV infection. 10.1111/tmi.12857
    Seroprevalence of chikungunya in southern odisha. Mohanty Indrani,Dash Muktikesh,Sahu Susmita,Narasimham M V,Panda Pritilata,Padhi Sanghamitra Journal of family medicine and primary care BACKGROUND:The emergence of chikungunya (CHIK) infection was observed in Odisha, India in 2006. Thereafter many cases with symptoms suggestive of CHIK were reported from different districts of Southern-Odisha. This study was aimed to know the seroprevalence, clinical presentations and seasonal trends of CHIK infection in this region. MATERIALS AND METHODS:This study was conducted in a tertiary hospital of this region. Serum samples received in the Department of Microbiology from various districts of Southern-Odisha from April 2011 to March 2012 were included in the study. The samples were tested for CHIK and dengue Immunoglobin M (IgM) antibodies by enzyme-linked immunosorbent assay and malaria parasite by immunochromatographic test (ICT) method. RESULTS:Out of the 678 serum samples tested, 174 were positive for CHIK, 15 for dengue and two samples were positive for both CHIK and dengue IgM antibodies. The most affected age group was 16-45 years. Females were more affected than males. CONCLUSION:The seroprevalence of CHIK among the suspected cases was 25.7%. Co-infection with CHIK and dengue was found to be 1.15%. The infection had spread to new areas during this outbreak. 10.4103/2249-4863.109939
    The native Wolbachia symbionts limit transmission of dengue virus in Aedes albopictus. Mousson Laurence,Zouache Karima,Arias-Goeta Camilo,Raquin Vincent,Mavingui Patrick,Failloux Anna-Bella PLoS neglected tropical diseases BACKGROUND:The chikungunya (CHIK) outbreak that struck La Reunion Island in 2005 was preceded by few human cases of Dengue (DEN), but which surprisingly did not lead to an epidemic as might have been expected in a non-immune population. Both arboviral diseases are transmitted to humans by two main mosquito species, Aedes aegypti and Aedes albopictus. In the absence of the former, Ae. albopictus was the only species responsible for viral transmission on La Reunion Island. This mosquito is naturally super-infected with two Wolbachia strains, wAlbA and wAlbB. While Wolbachia does not affect replication of CHIK virus (CHIKV) in Ae. albopictus, a similar effect was not observed with DEN virus (DENV). METHODS/PRINCIPAL FINDINGS:To understand the weak vectorial status of Ae. albopictus towards DENV, we used experimental oral infections of mosquitoes from La Reunion Island to characterize the impact of Wolbachia on DENV infection. Viral loads and Wolbachia densities were measured by quantitative PCR in different organs of Ae. albopictus where DENV replication takes place after ingestion. We found that: (i) Wolbachia does not affect viral replication, (ii) Wolbachia restricts viral density in salivary glands, and (iii) Wolbachia limits transmission of DENV, as infectious viral particles were only detected in the saliva of Wolbachia-uninfected Ae. albopictus, 14 days after the infectious blood-meal. CONCLUSIONS:We show that Wolbachia does not affect the replication of DENV in Ae. albopictus. However, Wolbachia is able to reduce viral infection of salivary glands and limit transmission, suggesting a role of Wolbachia in naturally restricting the transmission of DENV in Ae. albopictus from La Reunion Island. The extension of this conclusion to other Ae. albopictus populations should be investigated. 10.1371/journal.pntd.0001989
    Differential cell line susceptibility to the emerging Zika virus: implications for disease pathogenesis, non-vector-borne human transmission and animal reservoirs. Chan Jasper Fuk-Woo,Yip Cyril Chik-Yan,Tsang Jessica Oi-Ling,Tee Kah-Meng,Cai Jian-Piao,Chik Kenn Ka-Heng,Zhu Zheng,Chan Chris Chung-Sing,Choi Garnet Kwan-Yue,Sridhar Siddharth,Zhang Anna Jinxia,Lu Gang,Chiu Kin,Lo Amy Cheuk-Yin,Tsao Sai-Wah,Kok Kin-Hang,Jin Dong-Yan,Chan Kwok-Hung,Yuen Kwok-Yung Emerging microbes & infections Zika virus (ZIKV) is unique among human-pathogenic flaviviruses by its association with congenital anomalies and trans-placental and sexual human-to-human transmission. Although the pathogenesis of ZIKV-associated neurological complications has been reported in recent studies, key questions on the pathogenesis of the other clinical manifestations, non-vector-borne transmission and potential animal reservoirs of ZIKV remain unanswered. We systematically characterized the differential cell line susceptibility of 18 human and 15 nonhuman cell lines to two ZIKV isolates (human and primate) and dengue virus type 2 (DENV-2). Productive ZIKV replication (⩾2 log increase in viral load, ZIKV nonstructural protein-1 (NS1) protein expression and cytopathic effects (CPE)) was found in the placental (JEG-3), neuronal (SF268), muscle (RD), retinal (ARPE19), pulmonary (Hep-2 and HFL), colonic (Caco-2),and hepatic (Huh-7) cell lines. These findings helped to explain the trans-placental transmission and other clinical manifestations of ZIKV. Notably, the prostatic (LNCaP), testicular (833KE) and renal (HEK) cell lines showed increased ZIKV load and/or NS1 protein expression without inducing CPE, suggesting their potential roles in sexual transmission with persistent viral replication at these anatomical sites. Comparatively, none of the placental and genital tract cell lines allowed efficient DENV-2 replication. Among the nonhuman cell lines, nonhuman primate (Vero and LLC-MK2), pig (PK-15), rabbit (RK-13), hamster (BHK21) and chicken (DF-1) cell lines supported productive ZIKV replication. These animal species may be important reservoirs and/or potential animal models for ZIKV. The findings in our study help to explain the viral shedding pattern, transmission and pathogenesis of the rapidly disseminating ZIKV, and are useful for optimizing laboratory diagnostics and studies on the pathogenesis and counter-measures of ZIKV. 10.1038/emi.2016.99
    An analysis of community perceptions of mosquito-borne disease control and prevention in Sint Eustatius, Caribbean Netherlands. Leslie Teresa E,Carson Marianne,Coeverden Els van,De Klein Kirsten,Braks Marieta,Krumeich Anja Global health action BACKGROUND:In the Caribbean, mosquito-borne diseases are a public health threat. In Sint Eustatius, dengue, Chikungunya and Zika are now endemic. To control and prevent mosquito-borne diseases, the Sint Eustatius Public Health Department relies on the community to assist with the control of Aedes aegypti mosquito. Unfortunately, community based interventions are not always simple, as community perceptions and responses shape actions and influence behavioural responses Objective: The aim of this study was to determine how the Sint Eustatius population perceives the Aedes aegypti mosquito, mosquito-borne diseases and prevention and control measures and hypothesized that increased knowledge of the virus, vector, control and prevention should result in a lower AQ1 prevalence and incidence of mosquito-borne diseases. METHODS:This study was conducted in Sint Eustatius island in the Eastern Caribbean. We combined qualitative and quantitative designs. We conducted interviews and focus groups discussions among community member and health professional in 2013 and 2015. We also conducted cross-sectional survey to assess local knowledge on the vector, virus, and control and prevention. RESULTS:The population is knowledgeable; ©however, mosquito-borne diseases are not the highest health priority. While local knowledge is sometimes put into action, it happens on the 20 household/individual level as opposed to the community level. After the 2014 CHIK outbreak, there was an increase in knowledge about mosquito control and mosquito-borne diseases. DISCUSSION:In the context of Sint Eustatius, when controlling the Aedes population it may be a strategic option to focus on the household level rather than the community and build collaborations with households by supporting them when they actively practice mosquito 25 control. To further increase the level of knowledge on the significance of mosquito-borne diseases, it may also be an option to contextualize the issue of the virus, vector, prevention and control into a broader context. CONCLUSION:As evidenced by the increasing number of mosquito-borne diseases on the island, it appears that knowledge amongst the lay community may not be transferred into 30 action. This may be attributed to the perception of the Sint Eustatius populations that mosquitoes and the viruses they carry are not a high priority in comparison to other health concerns. 10.1080/16549716.2017.1350394
    Chikungunya Fever Among Patients with Acute Febrile Illness Attending a Tertiary Care Hospital in Mumbai. Galate Lata Baswanna,Agrawal Sachee R,Shastri Jayanthi S,Londhey Vikram Journal of laboratory physicians BACKGROUND:Chikungunya fever (CHIK) is an arboviral disease. Dengue fever (DENG) and CHIK are indistinguishable clinically and need to be differentiated by laboratory investigations. PURPOSE:This study aimed at estimating the seroprevalence of CHIK mono-infection and CHIK and DENG dual infection in suspected patients. We also analyzed the age, sex distribution, joint involvement, and relation of joint movement restriction with visual analog scale (VAS). MATERIALS AND METHODS:Two hundred patients clinically suspected with DENG and CHIK were enrolled from a Tertiary Care Hospital in Mumbai from April 2012 to October 2013. The detailed history and examination findings were recorded. Serum samples were subjected to DENG and CHIK immunoglobulin G (IgM) enzyme-linked immunosorbent assay (ELISA). RESULTS:The seroprevalence of CHIK was 12.5%. Mono-infection of CHIK was 3%, and CHIK and DENG dual infection was 9.5%. Most affected age group in CHIK cases was 46-60 years wherein female preponderance was seen. All 6 patients with CHIK mono-infection had fever and joint involvement; knee and elbow were the most commonly affected joints. All CHIK patients had VAS score of 6-10 with restricted joint movement. Of the patients with dual infection, the majorities were from 31 to 45 years with male preponderance; all had fever and joint pain mainly affecting knee and elbow. Of patients who had VAS score 6-10 in patients with dual infection, only 5.26% had restricted joint movement. CONCLUSION:IgM ELISA for Chikungunya infection should be included in the routine laboratory tests for acute febrile illness. 10.4103/0974-2727.180787
    Travel-Associated Chikungunya Cases in South Korea during 2009-2010. Cha Go Woon,Cho Jung Eun,Lee Eun Ju,Ju Young Ran,Han Myung Guk,Park Chan,Jeong Young Eui Osong public health and research perspectives OBJECTIVES:Chikungunya (CHIK) has been classified as a communicable disease group IV in South Korea since late 2010. Based on this, we investigated the extent of imported cases of CHIK in dengue-suspected individuals returning from dengue-endemic regions. METHODS:A total of 486 dengue-suspected serum samples were screened for CHIK by enzyme-linked immunosorbent assay (ELISA) and reverse transcription-polymerase chain reaction (RT-PCR) analysis. Further RT-PCR-positive samples were used for the viral culture, and CHIK was subsequently confirmed by sequence analysis of the culture samples. RESULTS:Five out of 107 dengue-positive samples were found to be positive for CHIK and 15 out of 379 dengue-negative samples were found to be positive for CHIK by immunoglobulin M ELISA. Further, a CHIK virus was isolated from one of the two RT-PCR-positive sera by cell culture and confirmed by sequence analysis. CONCLUSION:The present study documents the first evidence of travel-associated CHIK infection in South Korea. Considering the intense international traffic between countries, our finding emphasizes the urgent need for active patient and vector surveillance for timely response to reduce the introduction of CHIK in Korea. 10.1016/j.phrp.2013.04.008
    Retrospective seroepidemiological study of chikungunya infection in South Asia, Southeast Asia and the Pacific region. Ngwe Tun M M,Inoue S,Thant K Z,Talemaitoga N,Aryati A,Dimaano E M,Matias R R,Buerano C C,Natividad F F,Abeyewickreme W,Thuy N T T,Mai L T Q,Hasebe F,Hayasaka D,Morita K Epidemiology and infection Chikungunya virus (CHIKV) and Ross River virus (RRV) of the genus Alphavirus, family Togaviridae are mainly transmitted by Aedes mosquitoes and the symptoms they cause in patients are similar to dengue. A chikungunya (CHIK) outbreak re-emerged in several Asian countries during 2005-2006. This study aimed to clarify the prevalence of CHIKV infection in suspected dengue patients in six countries in South Asia and Southeast Asia. Seven hundred forty-eight serum samples were from dengue-suspected patients in South Asia and Southeast Asia, and 52 were from patients in Fiji. The samples were analysed by CHIKV IgM capture ELISA, CHIKV IgG indirect ELISA and focus reduction neutralization test against CHIKV or RRV. CHIK-confirmed cases in South Asia, particularly Myanmar and Sri Lanka, were 4·6%, and 6·1%, respectively; and in Southeast Asia, particularly Indonesia, the Philippines and Vietnam, were 27·4%, 26·8% and 25·0%, respectively. It suggests that CHIK was widely spread in these five countries in Asia. In Fiji, no CHIK cases were confirmed; however, RRV-confirmed cases represented 53·6% of suspected dengue cases. It suggests that RRV is being maintained or occasionally entering from neighbouring countries and should be considered when determining a causative agent for dengue-like illness in Fiji. 10.1017/S095026881600056X
    Recombinant CHIK virus E1 coat protein of 11 KDa with antigenic domains for the detection of Chikungunya. Yathi Krishna Kammara,Joseph Julia Mary,Bhasker Salini,Kumar Ramesh,Chinnamma Mohankumar Journal of immunological methods Chikungunya is an acute febrile illness caused by an alpha virus technically called as CHIK virus. A smaller size of CHIK virus E1 coat protein -11 kDa was expressed in prokaryotic expression system. The recombinant protein was purified and confirmed by western blot analysis. The positions of the antigenic domain in the protein were identified and the immunoreactivity of recombinant protein with anti-CHIK IgM antibodies was ascertained. The antigen showed an 88% sensitivity and 100% specificity by Indirect ELISA. No cross reactivity of the antigen was observed with anti-Dengue virus serum samples. The results strongly support that the recombinant CHIK coat protein could be used as a diagnostic antigen for the detection of Chikungunya by Indirect ELISA. The relevance of a smaller size recombinant antigen highlights its large scale application in serodiagnosis of CHIK virus since bacterial expression is more simple and cost effective than eukaryotic system. 10.1016/j.jim.2011.07.011
    Orally co-Infected Aedes albopictus from La Reunion Island, Indian Ocean, can deliver both dengue and chikungunya infectious viral particles in their saliva. Vazeille Marie,Mousson Laurence,Martin Estelle,Failloux Anna-Bella PLoS neglected tropical diseases BACKGROUND:First described in humans in 1964, reports of co-infections with dengue (DENV) and chikungunya (CHIKV) viruses are increasing, particularly after the emergence of chikungunya (CHIK) in the Indian Ocean in 2005-2006 due to a new variant highly transmitted by Aedes albopictus. In this geographic area, a dengue (DEN) outbreak transmitted by Ae. albopictus took place shortly before the emergence of CHIK and co-infections were reported in patients. A co-infection in humans can occur following the bite of two mosquitoes infected with one virus or to the bite of a mosquito infected with two viruses. Co-infections in mosquitoes have never been demonstrated in the field or in the laboratory. Thus, we question about the ability of a mosquito to deliver infectious particles of two different viruses through the female saliva. METHODOLOGY/PRINCIPAL FINDINGS:We orally exposed Ae. albopictus from La Reunion Island with DENV-1 and CHIKV isolated respectively during the 2004-2005 and the 2005-2006 outbreaks on this same island. We were able to show that Ae. albopictus could disseminate both viruses and deliver both infectious viral particles concomitantly in its saliva. We also succeeded in inducing a secondary infection with CHIKV in mosquitoes previously inoculated with DENV-1. CONCLUSIONS/SIGNIFICANCE:In this study, we underline the ability of Ae. albopictus to be orally co-infected with two different arboviruses and furthermore, its capacity to deliver concomitantly infectious particles of CHIKV and DENV in saliva. This finding is of particular concern as Ae. albopictus is still expanding its geographical range in the tropical as well as in the temperate regions. Further studies are needed to try to elucidate the molecular/cellular basis of this phenomenon. 10.1371/journal.pntd.0000706
    Seroprevalence of Infections with Dengue, Rift Valley Fever and Chikungunya Viruses in Kenya, 2007. Ochieng Caroline,Ahenda Petronella,Vittor Amy Y,Nyoka Raymond,Gikunju Stella,Wachira Cyrus,Waiboci Lilian,Umuro Mamo,Kim Andrea A,Nderitu Leonard,Juma Bonventure,Montgomery Joel M,Breiman Robert F,Fields Barry PloS one Arthropod-borne viruses are a major constituent of emerging infectious diseases worldwide, but limited data are available on the prevalence, distribution, and risk factors for transmission in Kenya and East Africa. In this study, we used 1,091 HIV-negative blood specimens from the 2007 Kenya AIDS Indicator Survey (KAIS 2007) to test for the presence of IgG antibodies to dengue virus (DENV), chikungunya virus (CHIKV) and Rift Valley fever virus (RVFV).The KAIS 2007 was a national population-based survey conducted by the Government of Kenya to provide comprehensive information needed to address the HIV/AIDS epidemic. Antibody testing for arboviruses was performed on stored blood specimens from KAIS 2007 through a two-step sandwich IgG ELISA using either commercially available kits or CDC-developed assays. Out of the 1,091 samples tested, 210 (19.2%) were positive for IgG antibodies against at least one of the three arboviruses. DENV was the most common of the three viruses tested (12.5% positive), followed by RVFV and CHIKV (4.5% and 0.97%, respectively). For DENV and RVFV, the participant's province of residence was significantly associated (P≤.01) with seropositivity. Seroprevalence of DENV and RVFV increased with age, while there was no correlation between province of residence/age and seropositivity for CHIKV. Females had twelve times higher odds of exposure to CHIK as opposed to DENV and RVFV where both males and females had the same odds of exposure. Lack of education was significantly associated with a higher odds of previous infection with either DENV or RVFV (p <0.01). These data show that a number of people are at risk of arbovirus infections depending on their geographic location in Kenya and transmission of these pathogens is greater than previously appreciated. This poses a public health risk, especially for DENV. 10.1371/journal.pone.0132645
    Baicalin, a metabolite of baicalein with antiviral activity against dengue virus. Moghaddam Ehsan,Teoh Boon-Teong,Sam Sing-Sin,Lani Rafidah,Hassandarvish Pouya,Chik Zamri,Yueh Andrew,Abubakar Sazaly,Zandi Keivan Scientific reports Baicalin, a flavonoid derived from Scutellaria baicalensis, is the main metabolite of baicalein released following administration in different animal models and human. We previously reported the antiviral activity of baicalein against dengue virus (DENV). Here, we examined the anti-DENV properties of baicalin in vitro, and described the inhibitory potentials of baicalin at different steps of DENV-2 (NGC strain) replication. Our in vitro antiviral experiments showed that baicalin inhibited virus replication at IC50 = 13.5 ± 0.08 μg/ml with SI = 21.5 following virus internalization by Vero cells. Baicalin exhibited virucidal activity against DENV-2 extracellular particles at IC50 = 8.74 ± 0.08 μg/ml and showed anti-adsorption effect with IC50 = 18.07 ± 0.2 μg/ml. Our findings showed that baicalin as the main metabolite of baicalein exerting in vitro anti-DENV activity. Further investigations on baicalein and baicalin to deduce its antiviral therapeutic effects are warranted. 10.1038/srep05452
    Dengue Hemorrhagic Fever at 60 Years: Early Evolution of Concepts of Causation and Treatment. Halstead Scott B,Cohen Sanford N Microbiology and molecular biology reviews : MMBR During the decade of the 1960s, the epidemiology of a new dengue disease, dengue hemorrhagic fever and dengue shock syndrome (DHF/DSS), was described by collaborative research performed by Thai scientists from many institutions and by workers at the U.S. Army's SEATO Medical Research Laboratory in Bangkok, Thailand. Careful clinical and physiological studies provided the initial description of DSS. DSS cases were caused by each of the four dengue viruses (DENV) and not chikungunya (CHIK) virus or DENV 5 and 6, were associated with a secondary-type dengue antibody response in children over the age of 1 year, were associated with a primary antibody response in infants less than 1 year old whose mothers had neutralizing antibodies to all four DENV, were associated more frequently with secondary DENV 2 infections than those due to DENV 1 and 3, and were more common in females than males over the age of 3 years. Robust laboratory methods for growth and recovery of DENV in tissue cultures were introduced. In addition, life-saving principles of fluid and plasma protein resuscitation of hypovolemia were described. Most epidemiological observations made during the decade of the 1960s have been confirmed in the succeeding 45 years. Much contemporary research on pathogenesis fails to address the two distinct immunological antecedents of DHF/DSS. 10.1128/MMBR.00009-15
    Development and evaluation of a 1-step duplex reverse transcription polymerase chain reaction for differential diagnosis of chikungunya and dengue infection. Dash Paban Kumar,Parida Manmohan,Santhosh S R,Saxena Parag,Srivastava Ambuj,Neeraja Mamidi,Lakshmi V,Rao P V Lakshmana Diagnostic microbiology and infectious disease Dengue (DEN) and chikungunya (CHIK) have emerged as the 2 most important arboviral infections of global significance. The similarities in clinical presentations, their circulation in the same geographic area, and the transmission through the same vector necessitate an urgent need for the differential diagnosis of these 2 infections. So far, no single assay is reported for differential diagnosis of these 2 infections. In this study, we report the development and evaluation of a 1-step single-tube duplex reverse transcription polymerase chain reaction (D-RT-PCR) assay by targeting E1 gene of CHIK and C-prM gene junction of DEN virus (DENV), respectively. The sensitivity of this assay was found to be better than conventional virus isolation and could detect as low as 100 copies of genomic RNA, which is equivalent to respective virus-specific RT-PCR. The evaluation was carried out with 360 clinical samples from recent CHIK and DEN outbreaks in India. This assay could also be able to detect dual infection of CHIK and DEN in 3 patients. The phylogenetic analysis based on the nucleotide sequencing of D-RT-PCR amplicon could precisely identify the genotypes of all the serotypes of DENV and CHIK viruses (CHIKV). These findings demonstrate the potential clinical and epidemiologic application of D-RT-PCR for rapid sensitive detection, differentiation, and genotyping of DENV and CHIKV in clinical samples. 10.1016/j.diagmicrobio.2008.05.002
    Development and Evaluation of an in-House IgM-Capture ELISA for the Detection of Chikungunya and Its Application to a Dengue Outbreak Situation in Kenya in 2013. Wasonga Caroline,Inoue Shingo,Kimotho James,Morita Kouichi,Ongus Juliette,Sang Rosemary,Musila Lillian Japanese journal of infectious diseases Chikungunya (CHIK) is a mosquito-borne viral disease. In the 2004 CHIK outbreak in Kenya, diagnosis was delayed because of the lack of accurate diagnostics. Therefore, this study aimed to develop and evaluate an in-house IgM-capture enzyme linked immunosorbent assay (ELISA) (in-house ELISA) for the detection of chikungunya virus (CHIKV) infections. Anti-CHIKV antibodies were raised in rabbits, purified and conjugated to horseradish peroxidase. These anti-CHIKV antibodies and cell-culture derived antigen were used to develop the ELISA. To validate the in-house ELISA, 148 patient sera from the 2005 Comoros CHIK outbreak were tested with centers for disease control and prevention (CDC) IgM-capture ELISA (CDC ELISA) and focus reduction neutralization test (FRNT) as reference assays. The in-house ELISA had a sensitivity of 97.6% and specificity of 81.3% compared to the CDC ELISA and a sensitivity of 91.1% and specificity of 96.7% compared to FRNT. Furthermore, 254 clinically suspected dengue patient samples from Eastern Kenya, collected in 2013, were tested for CHIKV IgM using the in-house ELISA. Out of the 254 samples, 26 (10.2%) were IgM positive, and of these 26 samples, 17 were further analyzed by FRNT and 14 (82.4%) were positive. The in-house ELISA was able to diagnose CHIKV infection among suspected dengue cases in the 2013 outbreak. 10.7883/yoken.JJID.2014.482
    Recently introduced Aedes albopictus in Corsica is competent to Chikungunya virus and in a lesser extent to dengue virus. Moutailler Sara,Barré Hélène,Vazeille Marie,Failloux Anna-Bella Tropical medicine & international health : TM & IH Aedes albopictus has been established in Europe for some decades rendering temperate countries vulnerable to tropical diseases. The Italian chikungunya (CHIK) outbreak in the summer of 2007 demonstrated that indigenous transmission of CHIK was possible in Europe. To estimate the risk of a CHIK outbreak in Corsica, we assessed the vector competence of A. albopictus established in the island since 2006 towards a CHIK variant (E1-A226V). A dengue serotype 2 virus was also tested. Experimental infections showed that A. albopictus was highly competent to CHIK virus (disseminated infection rates ranging from 75% to 100%) and to a lesser extent, to dengue virus (12.5-68.8%). Moreover, A. albopictus ensured a high level of viral replication and was able to transmit the virus as early as 2 days after ingestion of infected blood with around 1,000 viral RNA available in salivary glands. The risk for a local transmission of CHIK is thus likely in Corsica, if other parameters determining the vector capacity of A. albopictus are suitable. 10.1111/j.1365-3156.2009.02320.x
    Determination of B cell epitopes and evaluation of antigen capture ELISA for the earlier diagnosis of CHIK virus using anti-rCHIK E1 rabbit antibodies. Yathi Krishna Kammara,Bhasker Salini,Chinnamma Mohankumar Journal of immunological methods Chikungunya fever caused by an alpha virus has been generally considered as self limiting and non fatal. Recent reports on Chikungunya infection indicate high mortality rates due to the severity of the viral infection. For the early diagnosis of CHIK virus, the incubation period required for the development of antibodies in the serum of patients was a constraint for antigen based ELISA. The results of the present study demonstrates the development and evaluation of the antigen capture ELISA using recombinant anti-CHIK rabbit antibodies and anti-CHIK human antibody for more specific and rapid detection of CHIK viral antigen. A comprehensive bioinformatics analysis of the amino acid sequence of CHIK E1 protein was done for determining the antigenic residues, predominant B cell epitopes and their properties. Rabbit antibodies against recombinant CHIK E1 antigen was developed and purified. Antigen capture ELISA was done in 104 CHIK patient serum samples using anti-rCHIK E1 rabbit antibodies and anti-CHIK human antibodies. The highest rate of sensitivity (96%) and specificity (100%) was observed in the assay data and it highlights the accuracy of the test as a clinical diagnostic tool. No cross reactivity was observed with samples of dengue patients. Apart from the development and evaluation of the ELISA test, the dominant epitopes identified in the recombinant CHIK E1 protein sequence can be exploited for the development of a subunit Chikungunya vaccine. 10.1016/j.jim.2013.04.005
    Using Clinical Profiles and Complete Blood Counts to Differentiate Causes of Acute Febrile Illness during the 2009-11 Outbreak of Typhoid and Chikungunya in a Dengue Endemic Area. Laoprasopwattana Kamolwish,Limpitikul Wannee,Geater Alan Journal of tropical pediatrics BACKGROUND AND AIMS:After the 2009-11 outbreak of typhoid and chikungunya (CHIK) in Thailand, an effort was made to use complete blood counts and clinical profiles to differentiate these diseases to facilitate earlier specific treatment. METHODS:Patients aged 2-15 years having fever on first visit ≤3 days without localizing signs were enrolled retrospectively. Typhoid fever was confirmed by hemoculture, dengue by nonstructural protein-1 or polymerase chain reaction (PCR), and CHIK by PCR. Febrile children with negative results for these infections were classified as other acute febrile illness (AFI). RESULTS:Of the 264 cases, 56, 164, 25 and 19 had typhoid fever, dengue viral infection (DVI), CHIK and other AFI, respectively. Arthralgia had sensitivity, specificity, positive predictive value (PPV) and negative predictive value of 0.96, 0.97, 0.80 and 0.99, respectively, to differentiate CHIK from the others. After excluding CHIK by arthralgia, the PPV of the WHO 1997 and 2009 criteria for DVI increased from 0.65 and 0.73 to 0.95 and 0.84, respectively. Children with one of myalgia, headache or leukopenia had sensitivity of 0.84, specificity of 0.76 and PPV of 0.92 to differentiate DVI from typhoid and other AFIs. Patients with one of abdominal pain, diarrhea or body temperature >39.5°C were more likely to have typhoid fever than another AFI with PPV of 0.90. CONCLUSION:Using this flow chart can help direct physicians to perform more specific tests to confirm the diagnosis and provide more specific treatment. Nevertheless, clinical follow-up is the most important tool in unknown causes of febrile illness. 10.1093/tropej/fmaa006
    Assessing the spreading patterns of dengue infection and chikungunya fever outbreaks in lower southern Thailand using a geographic information system. Ditsuwan Thanittha,Liabsuetrakul Tippawan,Chongsuvivatwong Virasakdi,Thammapalo Suwich,McNeil Edward Annals of epidemiology PURPOSE:The aims of this study were to assess the incidence of dengue infection (DEN) and chikungunya fever (CHIK) and determine the direction and speed of CHIK between August 2008 and June 2009 in lower southern Thailand. METHODS:The National Communicable Disease Surveillance System database and a geographic information system containing data on case locations were combined. R and ArcView were used for identifying incidence, direction, and speed of disease outbreaks. RESULTS:A total of 27,166 patients were identified, of which 3319 and 23,847 had DEN and CHIK, with incidences of 73 and 521 per 100,000, respectively. The direction of the CHIK outbreak moved from south to north with a median speed of 7.5 km per week. CHIK cases increased after 6 weeks of increasing cumulative rainfall with variation of average daily temperatures (23.7-30.7 degrees C) per week. There was no clear association of DEN with climate variables. CONCLUSIONS:The combination of surveillance and geographic information system data of DEN and CHIK can be used to determine the speed and direction of disease spread. DEN is endemic, but CHIK is an emerging disease. Because of the rapid spread of CHIK, strict and timely integrated vector control programs after case notification must be implemented. 10.1016/j.annepidem.2010.12.002
    Dengue and Chikungunya Virus Co-infections: The Inside Story. Londhey Vikram,Agrawal Sachee,Vaidya Nilima,Kini Seema,Shastri J S,Sunil Sujatha The Journal of the Association of Physicians of India INTRODUCTION:There have been various studies from India describing the acute presentation and the long-term sequalae of Chikungunya (CHIKV) infection. However, there are very few studies discussing the Chikungunya-Dengue (DENV) co-infection from Western India. The present project was undertaken to study the clinical features of Dengue and Chikungunya co-infection and compare with Chikungunya mono-infection; correlate the clinical findings with seroprevalence and molecular identification of Dengue and Chikungunya using IgM ELISA and RTPCR. MATERIAL AND METHODS:Three hundred suspected cases of Dengue and/or Chikungunya patients from out patients department and indoor wards, more than 12 years of age suffering from acute febrile illness, joint pains and rash for less than 10 days were included from June 2010 to April 2015. Proven cases of malaria, enteric fever, leptospirosis were excluded from the study. Leptospira IgM, Dengue IgM and PCR, Chikungunya IgM and PCR was done on all 300 samples. RESULTS:Sero-surveillance of the patients revealed that 59% (177) patients were positive for Dengue IgM alone, while 2% (6) tested positive for Chikungunya IgM alone. 6.7% (20) patients tested positive for Dengue and Chikungunya both. Ninty seven (32.3%) patients were negative for Dengue and Chikungunya. Of the 300 samples, 7% (21) were positive for DENV, 35% (105) were positive for CHIKV, 10% (30) were both DENV and CHIKV positive and 48% (144) were negative for both through RT-PCR. DISCUSSION:In our study, the patients of CHIKV mono-infection and DENV + CHIK co-infection had high VAS score, morning stiffness, arthralgias, restriction of joint movements as compared to patients with DENV mono infection. Patients of dengue mono infection had bone pains and myalgias in addition to joint pains; however there was restriction of joint movements in only 13.2% as compared with 100% of mono CHIKV or dual infection. These clinical features can be helpful in distinguishing DENV mono infection as compared to co-infection. The study highlights the diagnostic importance of RT-PCR in CHIKV and DENV co-infection, as 10% cases were identified using RT-PCR as compared to 6.7% cases by IgM antibodies.
    High efficiency of temperate Aedes albopictus to transmit chikungunya and dengue viruses in the Southeast of France. Vega-Rua Anubis,Zouache Karima,Caro Valerie,Diancourt Laure,Delaunay Pascal,Grandadam Marc,Failloux Anna-Bella PloS one BACKGROUND:Since 2005, cases of chikungunya (CHIK) were caused by an unusual vector, Aedes albopictus. This mosquito, present in Europe since 1979, has gained importance since its involvement in the first CHIK outbreak in Italy in 2007. The species is capable of transmitting experimentally 26 arboviruses. However, the vectorial status of its temperate populations has remained little investigated. In 2010, autochthonous cases of CHIK and dengue (DEN) were reported in southeastern France. We evaluated the potential of a French population of Ae. albopictus in the transmission of both viruses. METHODOLOGY AND PRINCIPAL FINDINGS:We used two strains of each virus, CHIK AND DEN: one strain was isolated from an imported case, and one from an autochthonous case. We used as controls Aedes aegypti from India and Martinique, the source of the imported cases of CHIK and DEN, respectively. We showed that Ae. albopictus from Cagnes-sur-Mer (AL-CSM) was as efficient as the typical tropical vector Ae. aegypti from India to experimentally transmit both CHIK strains isolated from patients in Fréjus, with around 35-67% of mosquitoes delivering up to 14 viral particles at day 3 post-infection (pi). The unexpected finding came from the high efficiency of AL-CSM to transmit both strains of DENV-1 isolated from patients in Nice. Almost 67% of Ae. albopictus AL-CSM which have ensured viral dissemination were able to transmit at day 9 pi when less than 21% of the typical DEN vector Ae. aegypti from Martinique could achieve transmission. CONCLUSIONS/SIGNIFICANCE:Temperate Ae. albopictus behaves differently compared to its counterpart from tropical regions, where recurrent epidemic outbreaks occur. Its potential responsibility for outbreaks in Europe should not be minimized. 10.1371/journal.pone.0059716
    Low to medium-low risk perception for dengue, chikungunya and Zika outbreaks by infectious diseases physicians in France, Western Europe. Le Tyrant Marion,Bley Daniel,Leport Catherine,Alfandari Serge,Guégan Jean-François BMC public health BACKGROUND:Many tropical countries are currently experiencing dengue (DEN), chikungunya (CHIK) and also more recently Zika (ZIKA) epidemics (particularly in Latin America). Although the risk of transmission and spread of these infections in temperate regions remains a controversial issue, vector-borne diseases have been widely reported in the media and have been the focus of preventive strategies by national and international policy-makers and public health authorities. In this context, we wanted to determine the extent of risk perception in infectious diseases (ID) physicians of the current and future risk of arboviral disease introduction, autochthonous case development and epidemic scenarios in France, Western Europe. METHODS:To this aim, we developed an original standardized questionnaire survey which was disseminated by the French Infectious Diseases Society to ID physician members. RESULTS:We found that ID physicians perceived the risk of introduction and outbreak development of DEN, CHIK and ZIKA in France to be low to medium-low. Generalized Linear Model(s) identified medical school training, the extent of professional experience, and awareness of the French national plan regarding arboviral infections as significant predictors for lower risk perception among respondents. CONCLUSION:Despite the fact that arboviral diseases are increasingly being imported into France, sometimes resulting in sporadic autochtonous transmission, French ID physicians do not perceive the risk as high. Better communication and education targeting health professionals and citizens will be needed to enhance the effectiveness of the French national plan to prepare against arboviral diseases. 10.1186/s12889-019-7317-9
    Experimental Zika virus infection in : Susceptibility, transmission & co-infection with dengue & chikungunya viruses. Mourya Devendra T,Gokhale Mangesh D,Majumdar Triparna D,Yadav Pragya D,Kumar Vimal,Mavale Mangala S The Indian journal of medical research Background & objectives:There are reports about the susceptibility of Aedes mosquitoes to ZIKV from various countries, however, no such information is available from Indian sub-continent, although, high level of group cross-reactivity of ZIKV with other flaviviruses has been reported. During outbreak situations, many cases of Dengue (DEN) and Chikungunya (CHIK) are reported. In such scenario, vector mosquitoes are likely to get co-infection/secondary-infection with one or other virus. The present study was carried out to determine the susceptibility of Indian strain of Aedes aegypti to Zika virus (ZIKV) strain (MR-766) and the effect of co-infection/super-infection with either dengue virus (serotype-2) (DENV) or chikungunya virus (CHIKV) on ZIKV replication. Methods:Ae. aegypti mosquitoes used in this study were reared for many generations since 1980 at laboratory colony maintained at the ICMR-National Institute of Virology, Pune, India. Transmissibility of ZIKV from infected mosquitoes to suckling mice was also studied. Mosquitoes were experimentally infected with ZIKV and super-infected with either DENV or CHIKV via membrane-feeding route and incubated for 14 days at 28±2°C and humidity of 85±5 per cent. Replication of these viruses in mosquitoes was confirmed using real-time reverse transcription-polymerase chain reaction and immunofluorescence assay. Twenty infected mosquitoes were allowed to feed upon four suckling CD1 mice for about 30 min. Transmission of the ZIKV by infected mosquitoes to suckling mice was confirmed by the appearance of clinical signs and the presence of viral RNA in different organs. Results:Concomitant infection of mosquitoes with all the three viruses showed simultaneous propagation of all three viruses, confirmed by real time RT-PCR and IFA. Infection of mosquitoes with CHIKV followed by ZIKV showed positivity in individual head squashes (7%) for both viruses using IFA; only 8.3 per cent showed dual positivity with primary infection of ZIKV followed by DENV; 8.3 per cent dual infection positivity was observed when infected with DENV followed by ZIKV; 5 per cent showed dual infection was observed when infected with ZIKV followed by CHIKV. Ae. aegypti was found to be susceptible to ZIKV strain as ZIKV could be detected from the second post-infection day (PID) in infected mosquitoes. Transmission of ZIKV to mice by the bite of infected Ae. aegypti establishes this species as a potential vector. Interpretation & conclusions:From super-infection experiments, it was concluded that ZIKV might have a relative advantage in replication dynamics over DENV. Vertical transmission was not observed for ZIKV in experimentally infected mosquitoes (n=920 larvae). Further studies are required to understand the possibility of silently circulating ZIKV in India, which remain non-detected because of lack of surveillance. 10.4103/ijmr.IJMR_1142_17
    Patterns of occurrence of dengue and chikungunya, and spatial distribution of mosquito vector Aedes albopictus in Swabi district, Pakistan. Hira Fatima Syeda,Asad Ali,Farrah Zaidi,Basit Rasheed Syed,Mehreen Fatima,Muhammad Khisroon Tropical medicine & international health : TM & IH OBJECTIVE:Two principal vector species, Aedes aegypti and Aedes albopictus, are known for transmission of dengue (DEN) and chikungunya (CHK) in Pakistan. We aimed to investigate their spatial and temporal distribution. METHODS AND RESULTS:The Maximum Entropy algorithm revealed current climatic suitability of A. albopictus by highlighting variables contributing to its spatial distribution: Land use cover was the most important environmental factor (63.1%) followed by elevation-normalised difference vegetation index (10.9%), NDVI (8.5%) and annual precipitation (7.9%). As per Normalized Difference Vegetation Index values, the vector's presence was highly likely in areas with little vegetation such as built-up spaces or uncultivated fields, and in areas with sparse vegetation such as grasslands and cultivated fields. Temperature variables showed differing effects on vector ecology with annual temperature being the most important. Logistic regression models showed that presence of the vector, build-up and distance to roads contributed significantly to the distribution of both DEN and CHIK. CONCLUSION:In Swabi, the mean temperatures of warmest and driest quarters are more important in the spatial distribution of A. albopictus than mean temperatures of the wettest and coldest quarters. Finally, disease modelling reflects a high probability for both DEN and CHIK in the same regions over a huge area. 10.1111/tmi.13125
    Space-time clusters and co-occurrence of chikungunya and dengue fever in Colombia from 2015 to 2016. Desjardins M R,Whiteman A,Casas I,Delmelle E Acta tropica Vector-borne diseases (VBDs) infect over one billion people and are responsible for over one million deaths each year, globally. Chikungunya (CHIK) and Dengue Fever (DENF) are emerging VBDs due to overpopulation, increases in urbanization, climate change, and other factors. Colombia has recently experienced severe outbreaks of CHIK AND DENF. Both viruses are transmitted by the Aedes mosquitoes and are preventable with a variety of surveillance and vector control measures (e.g. insecticides, reduction of open containers, etc.). Spatiotemporal statistics can facilitate the surveillance of VBD outbreaks by informing public health officials where to allocate resources to mitigate future outbreaks. We utilize the univariate Kulldorff space-time scan statistic (STSS) to identify and compare statistically significant space-time clusters of CHIK and DENF in Colombia during the outbreaks of 2015 and 2016. We also utilize the multivariate STSS to examine co-occurrences (simultaneous excess incidences) of DENF and CHIK, which is critical to identify regions that may have experienced the greatest burden of VBDs. The relative risk of CHIK and DENF for each Colombian municipality belonging to a univariate and multivariate cluster is reported to facilitate targeted interventions. Finally, we visualize the results in a three-dimensional environment to examine the size and duration of the clusters. Our approach is the first of its kind to examine multiple VBDs in Colombia simultaneously, while the 3D visualizations are a novel way of illustrating the dynamics of space-time clusters of disease. 10.1016/j.actatropica.2018.04.023
    Coinfection of chikungunya and dengue viruses: A serological study from North Western region of Punjab, India. Kaur Maninder,Singh Kanwardeep,Sidhu Shailpreet K,Devi Pushpa,Kaur Manpreet,Soneja Sapna,Singh Nacchartarjit Journal of laboratory physicians INTRODUCTION:Dengue and chikungunya (CHIK) infections appear to be increasing in all parts of India. mosquitoes are common vectors for dengue virus (DENV) and CHIK virus (CHIKV). In areas where both viruses cocirculate, they can be transmitted together. There are very few studies discussing the dengue-chik coinfection from Punjab region of India. The present study was undertaken to study the clinical features of dengue-CHIK coinfection and compare with monoinfection. MATERIALS AND METHODS:IgM antibody capture (MAC) ELISA for dengue IgM and CHIK IgM and ELISA for nonstructural protein 1 antigen was performed on serum samples obtained from suspected patients. RESULTS:Out of total 3160 samples from suspected patients for dengue infection, 2178 (68.92%) samples were positive for DENV while CHIK IgM antibodies were positive in 127 patients out of the total suspected 373 cases (34.04%). In addition to this, 283 samples were tested for both viruses, out of which 27 sera were positive (9.54%) for coinfection of dengue and CHIK. The comparison of signs and symptoms showed that the coinfected patients had fever in all cases while rash was seen in only 30% cases. Arthralgia (79%) and thrombocytopenia (77%) was seen in significant number of coinfected cases thus revealing overlapping nature of dengue-CHIK coinfection. CONCLUSION:Increase in the number of Dengue and Chikungunya infections and their cocirculation is an important public health concern which warrants the implementation of strict control measures. 10.4103/JLP.JLP_13_18
    Differential diagnosis of Chikungunya, dengue viral infection and other acute febrile illnesses in children. Laoprasopwattana Kamolwish,Kaewjungwad Lamy,Jarumanokul Roongrueng,Geater Alan The Pediatric infectious disease journal BACKGROUND:Clinical manifestations of chikungunya (CHIK) are similar to those of dengue. It would be useful to be able to identify clinical manifestations that could reliably help to differentiate CHIK from dengue and other acute febrile illnesses during a CHIK outbreak in a dengue-endemic area. METHODS:A prospective cohort study was conducted between April and July 2009 in children aged 1 month to 15 years who lived in a CHIK outbreak area in southern Thailand and who had fever <7 days with arthralgia/arthritis, myalgia or rash. CHIK was confirmed by real-time polymerase chain reaction or the indirect immunofluorescence test. RESULTS:Fifty patients were suspected of having CHIK, of whom 32 were confirmed, 1 had coinfection with dengue viral infection (DVI), 10 had dengue alone and 7 had an acute febrile illness. The specificity and positive predictive value of fever and arthralgia together to diagnose CHIK were 47.1% and 74.2%, and the corresponding values of the standard clinical triad (fever, arthralgia, rash) were 70.6% and 83.3%, respectively. Fever ≤ 2 days, skin rash during fever and white blood cell count ≥ 5000 cells/mm(3) were independently and significantly associated with CHIK in comparison with DVI and acute febrile illnesses, with relative risk ratios (95% confidence intervals) of 10.4 (0.9-116) and 13.7 (1.3-145), 13.8 (1.2-164) and 14.8 (1.6-168), and 18.3 (1.7-194) and 1.8 (0.1-20.6), respectively. CONCLUSIONS:During a CHIK outbreak in a DVI-endemic area, overdiagnosis of CHIK was common. Skin rash during fever and white blood cell count ≥ 5000 cells/mm(3) or specific antigen testing (if available) can be helpful in differentiating CHIK from DVI. 10.1097/INF.0b013e31824bb06d
    Chikungunya Detection during Dengue Outbreak in Sumatra, Indonesia: Clinical Manifestations and Virological Profile. Sasmono R Tedjo,Perkasa Aditya,Yohan Benediktus,Haryanto Sotianingsih,Yudhaputri Frilasita A,Hayati Rahma F,Ma'roef Chairin Nisa,Ledermann Jeremy P,Aye Myint Khin Saw,Powers Ann M The American journal of tropical medicine and hygiene Chikungunya fever (CHIK) is an acute viral infection caused by infection with chikungunya virus (CHIKV). The disease affects people in areas where certain species mosquito vectors are present, especially in tropical and subtropical countries. Indonesia has witnessed CHIK disease since the early 1970s with sporadic outbreaks occurring throughout the year. The CHIK clinical manifestation, characterized by fever, headache, and joint pain, is similar to that of dengue (DEN) disease. During a molecular study of a DEN outbreak in Jambi, Sumatra, in early 2015, DENV-negative samples were evaluated for evidence of CHIKV infection. Among 103 DENV-negative samples, eight samples were confirmed (7.8%) as positive for CHIKV by both molecular detection and virus isolation. The mean age of the CHIK patients was 21.3 ± 9.1 (range 11-35 years). The clinical manifestations of the CHIK patients were mild and mimicked DEN, with fever and headache as the main symptoms. Only three out of eight patients presented with classical joint pain. Sequencing of the envelope glycoprotein E1 gene and phylogenetic analysis identified all CHIKV isolates as belonging to the Asian genotype. Overall, our study confirms sustained endemic CHIKV transmission and the presence of multiple arboviruses circulating during a DEN outbreak in Indonesia. The co-circulation of arboviruses poses a public health threat and is likely to cause misdiagnosis and underreporting of CHIK in DEN-endemic areas such as Indonesia. 10.4269/ajtmh.16-0935
    A Re-Examination of the History of Etiologic Confusion between Dengue and Chikungunya. Kuno Goro PLoS neglected tropical diseases Contrary to the perception of many researchers that the recent invasion of chikungunya (CHIK) in the Western Hemisphere marked the first episode in history, a recent publication reminded them that CHIK had prevailed in the West Indies and southern regions of the United States from 1827-1828 under the guise of "dengue" (DEN), and that many old outbreaks of so-called "dengue" actually represented the CHIK cases erroneously identified as "dengue." In hindsight, this confusion was unavoidable, given that the syndromes of the two diseases-transmitted by the same mosquito vector in urban areas-are very similar, and that specific laboratory-based diagnostic techniques for these diseases did not exist prior to 1940. While past reviewers reclassified problematic "dengue" outbreaks as CHIK, primarily based on manifestation of arthralgia as a marker of CHIK, they neither identified the root cause of the alleged misdiagnosis nor did they elaborate on the negative consequences derived from it. This article presents a reconstructed history of the genesis of the clinical definition of dengue by emphasizing problems with the definition, subsequent confusion with CHIK, and the ways in which physicians dealt with the variation in dengue-like ("dengue") syndromes. Then, the article identifies in those records several factors complicating reclassification, based on current practice and standards. These factors include terms used for characterizing joint problems, style of documenting outbreak data, frequency of manifestation of arthralgia, possible involvement of more than one agent, and occurrence of the principal vector. The analysis of those factors reveals that while some of the old "dengue" outbreaks, including the 1827-1828 outbreaks in the Americas, are compatible with CHIK, similar reclassification of other "dengue" outbreaks to CHIK is difficult because of a combination of the absence of pathognomonic syndrome in these diseases and conflicting background information. 10.1371/journal.pntd.0004101
    Chikungunya and dengue virus infections during pregnancy: seroprevalence, seroincidence and maternal-fetal transmission, southern Thailand, 2009-2010. Laoprasopwattana K,Suntharasaj T,Petmanee P,Suddeaugrai O,Geater A Epidemiology and infection Limited information is available on the seroprevalence of chikungunya virus (CHIKV) infection and maternal-fetal transmission incidence of CHIKV and dengue virus (DENV) infections during the 2008-2009 CHIKV outbreak in southern Thailand. A community-based post-epidemic seroprevalence study was conducted in parturient women admitted to the Thepa District Hospital in Songkhla Province, Thailand, for delivery from November 2009 to May 2010. The women were tested for chikungunya (CHIK) IgM/IgG and dengue (DEN) IgM/IgG. Cord blood samples were also tested for CHIK IgM or DEN IgM in women who tested positive for CHIK IgM or DEN IgM, respectively. The seroprevalence of CHIKV infection (CHIK IgM or IgG positive) was 227/319 (71·2%) with pre-outbreak seroprevalence (IgM-/IgG+) of 43·6% and the seroprevalence of DENV infection was 288/319 (90·3%). Complications during pregnancy, newborn outcomes and congenital anomalies were not different in those who had recent, remote or no CHIKV infections. None of the newborns whose mothers were CHIK or DEN IgM positive had cord blood positive for both CHIK and DEN IgM. In conclusion, both CHIKV and DENV are endemic in southern Thailand; during the recent CHIKV outbreak CHIK seroprevalence increased from 43·6% to 71·2%. 10.1017/S0950268815001065
    Comment on "Chik sign and dengue". Joob Beuy,Wiwanitkit Viroj Pediatric dermatology 10.1111/pde.13968
    The chik sign in dengue. Bhatia Shibani S,Shenoi Shrutakirthi D,Hebbar Shrikiran A,Kayarkatte Manasa N Pediatric dermatology The "chik sign" is considered to be one of the most common cutaneous features of chikungunya fever and has been considered unique to this disorder. It consists of brownish hyperpigmentation involving the nose. We report a case of a 3-year-old boy with dengue infection who presented with macular hyperpigmentation of nose simulating the chik sign. Hyperpigmentation is an unusual cutaneous manifestation in cases of dengue. 10.1111/pde.13883
    [Co-infection by Chikungunya virus (CHIK-V) and dengue virus (DEN-V) during a recent outbreak in Cali, Colombia: Report of a fatal case]. Rosso Fernando,Pacheco Robinson,Rodríguez Sarita,Bautista Diego Revista chilena de infectologia : organo oficial de la Sociedad Chilena de Infectologia The recent outbreaks of Chikungunya (CHIK-V) virus in endemic areas of dengue (DEN-V) could increase the risk of co-infection. CHIK infection has been considered not severe and with very unusual mortality, however DEN is associated with severe manifestations and increased mortality. Little is known about coinfection. It is possible that co-infection could generate severe cases. We present a case report of co-infection DEN-V -3 and CHIK-V in an elderly patient who developed acute renal failure, dengue shock syndrome (DSS), progresses to multiple organ failure and died. With the recent emergence of CHIK-V in Colombia, the possibility of co-infection with DEN-V should be suspected, especially in severe cases. 10.4067/S0716-10182016000400013