Chikungunya Virus Net is the web resource for anyone interested in chikungunya. The objectives of Chikungunya Virus Net are to be the public and professional information resource for chikungunya and to serve as a network in the exchange of information and news related to chikungunya.
Chikungunya virus (CHIKV) is an insect-borne virus, of the genus Alphavirus, that is spread by Aedes mosquitoes. Chikungunya infection causes fever and severe joint pain. Other symptoms include muscle pain, headache, nausea, fatigue and rash. The disease shares some clinical signs with dengue, and can be misdiagnosed in areas where dengue is common. There have been recent breakouts of chikungunya in Africa, Asia and the Indian subcontinent. In recent decades mosquito vectors of chikungunya have spread to Europe and the Americas. In 2007, disease transmission was reported for the first time in Europe. There is no cure for the disease. Treatment is focused on relieving the symptoms.
- New York reports 100 chikungunya cases as national count continues rise - Outbreak News Today
Thu, 21 Aug 2014 10:57:
- Chikungunya virus has been contained - The Cayman Reporter
Thu, 21 Aug 2014 05:23:
- Officials to review practices to contain chikungunya virus - Cayman Compass
Thu, 21 Aug 2014 05:04:
- Seven additional cases of Chikungunya confirmed in Jamaica - Jamaica Observer
Wed, 20 Aug 2014 23:38:
- Chikungunya vaccine protects against virus in small Phase I study - FierceVaccines
Wed, 20 Aug 2014 22:34:
- Florida has two more local chikungunya cases - Examiner.com
Wed, 20 Aug 2014 22:16:
- Chikungunya vaccine shows promise - The Hindu
Wed, 20 Aug 2014 20:36:
- Palm Beach County reports two additional indigenous chikungunya cases - Outbreak News Today
Wed, 20 Aug 2014 20:34:
- Latin America Has No Antibodies to Fight Chikungunya Fever - World Bank Group
Wed, 20 Aug 2014 18:16:
- DOD looks to help slow the spread of chikungunya virus - Defense Systems
Wed, 20 Aug 2014 15:25:
- An in vitro assay to study chikungunya virus RNA synthesis and the mode of action of inhibitors.
Albulescu IC, Tas A, Scholte FE, et al. An in vitro assay to study chikungunya virus RNA synthesis and the mode of action of inhibitors. [JOURNAL ARTICLE]J Gen Virol 2014 Aug 18.AbstractPublisher Full TextChikungunya virus (CHIKV) is a re-emerging mosquito-borne alphavirus that causes severe persistent arthralgia. To better understand the molecular details of CHIKV RNA synthesis and the mode of action of inhibitors, we have developed an in vitro assay to study CHIKV replication/transcription complexes isolated from infected cells. In this assay (32)P-CTP was incorporated into CHIKV genome and subgenomic (sg) RNA, as well as into a ~7.5 kb positive-stranded RNA, termed RNA II. We mapped RNA II, which was also found in CHIKV-infected cells, to the 5'-end of the genome up to the start of the sgRNA promoter region. Most of the RNA-synthesizing activity, negative-stranded RNA and a relatively large proportion of nsP1 and nsP4 were recovered from a crude membrane fraction obtained by pelleting at 15,000 x g. Positive-stranded RNA was mainly found in the cytosolic S15 fraction, suggesting it was released from the membrane-associated RTCs. The newly synthesized RNA was relatively stable and remained protected from cellular nucleases, possibly by encapsidation. A set of compounds that inhibit CHIKV replication in cell culture was tested in the in vitro RTC assay. In contrast to 3'dNTPs, chain terminators that acted as potent inhibitors of RTC activity, ribavirin triphosphate and 6-aza-UTP did not affect the RNA-synthesizing activity in vitro. In conclusion, this in vitro assay for CHIKV RNA synthesis is a useful tool for mechanistic studies on the CHIKV RTC and mode of action studies on compounds with anti-CHIKV activity.
- Coexistence of Philodina roseola (Rotifera: Bdelloidea) with larvae of Aedes aegypti in India.
Muniaraj M, Sathish Babu R Coexistence of Philodina roseola (Rotifera: Bdelloidea) with larvae of Aedes aegypti in India. [Journal Article]Trop Biomed 2014 Jun; 31(2):207-14.The vector mosquitoes, Aedes aegypti and Aedes albopictus of dengue and Chikungunya fever are closely associated with human habitations and adapted to feed on human blood. They undergo larval and pupal development in natural and artificial freshwater collections in the urban and peri-urban environment. Although reports are available about the feeding behaviour of the thriving mosquito larvae, much information is still required to understand the successful survival of Aedes mosquitoes in small and temporary water collections. This study was undertaken to determine the co-existence and prevalence of Philodina roseola and other Bdelloid rotifers in the container habitats of Ae. aegypti mosquitoes. The investigation was conducted in 43 villages which belong to four districts in South India, affected by the epidemic of either dengue or Chikungunya fever. A total of 2093 houses and 12980 containers were examined for Aedes breeding and those containers with Aedes larvae were chosen for further investigation. The investigation showed that, the P. roseola was found associated in 502 (98.2%) containers, P. roseola along with other Philodina sp. in 126 containers (25%) and P. roseola along with other Philodina sp. and other Bdelloid rotifers found in 93 containers (19%). Since the members of the genus Philodina can survive desiccation, reproduce by parthenogenesis, can be transported by wind easily and more importantly, it can incorporate the genome of other organisms including viruses, understanding the co-existence and relationship of Philodina sp. with Aedes larvae would be helpful in the control of Aedes breeding and the control measures can be designed keeping the association of Bdelloids with Aedes in mind.
- Safety and tolerability of chikungunya virus-like particle vaccine in healthy adults: a phase 1 dose-escalation trial.
Chang LJ, Dowd KA, Mendoza FH, et al. Safety and tolerability of chikungunya virus-like particle vaccine in healthy adults: a phase 1 dose-escalation trial. [JOURNAL ARTICLE]Lancet 2014 Aug 14.Chikungunya virus-a mosquito-borne alphavirus-is endemic in Africa and south and southeast Asia and has recently emerged in the Caribbean. No drugs or vaccines are available for treatment or prevention. We aimed to assess the safety, tolerability, and immunogenicity of a new candidate vaccine.VRC 311 was a phase 1, dose-escalation, open-label clinical trial of a virus-like particle (VLP) chikungunya virus vaccine, VRC-CHKVLP059-00-VP, in healthy adults aged 18-50 years who were enrolled at the National Institutes of Health Clinical Center (Bethesda, MD, USA). Participants were assigned to sequential dose level groups to receive vaccinations at 10 μg, 20 μg, or 40 μg on weeks 0, 4, and 20, with follow-up for 44 weeks after enrolment. The primary endpoints were safety and tolerability of the vaccine. Secondary endpoints were chikungunya virus-specific immune responses assessed by ELISA and neutralising antibody assays. This trial is registered with ClinicalTrials.gov, NCT01489358.25 participants were enrolled from Dec 12, 2011, to March 22, 2012, into the three dosage groups: 10 μg (n=5), 20 μg (n=10), and 40 μg (n=10). The protocol was completed by all five participants at the 10 μg dose, all ten participants at the 20 μg dose, and eight of ten participants at the 40 μg dose; non-completions were for personal circumstances unrelated to adverse events. 73 vaccinations were administered. All injections were well tolerated, with no serious adverse events reported. Neutralising antibodies were detected in all dose groups after the second vaccination (geometric mean titres of the half maximum inhibitory concentration: 2688 in the 10 μg group, 1775 in the 20 μg group, and 7246 in the 40 μg group), and a significant boost occurred after the third vaccination in all dose groups (10 μg group p=0·0197, 20 μg group p<0·0001, and 40 μg group p<0·0001). 4 weeks after the third vaccination, the geometric mean titres of the half maximum inhibitory concentration were 8745 for the 10 μg group, 4525 for the 20 μg group, and 5390 for the 40 μg group.The chikungunya VLP vaccine was immunogenic, safe, and well tolerated. This study represents an important step in vaccine development to combat this rapidly emerging pathogen. Further studies should be done in a larger number of participants and in more diverse populations.Intramural Research Program of the Vaccine Research Center, National Institute of Allergy and Infectious Diseases, and National Institutes of Health.
- Chikungunya virus control: is a vaccine on the horizon?
Powers AM Chikungunya virus control: is a vaccine on the horizon? [JOURNAL ARTICLE]Lancet 2014 Aug 14.
- Chikungunya virus: new risk to transfusion safety in the Americas.
Petersen LR, Epstein JS Chikungunya virus: new risk to transfusion safety in the Americas. [Editorial]Transfusion 2014 Aug; 54(8):1911-5.
- Kinetic and phenotypic analysis of CD8+ T cell responses after priming with alphavirus replicons and homologous or heterologous booster immunizations.
Knudsen ML, Ljungberg K, Kakoulidou M, et al. Kinetic and phenotypic analysis of CD8+ T cell responses after priming with alphavirus replicons and homologous or heterologous booster immunizations. [JOURNAL ARTICLE]J Virol 2014 Aug 13.AbstractPublisher Full TextAlphavirus replicons are potent inducers of CD8(+) T cell responses and thus constitute an attractive vaccine vector platform for developing novel vaccines. However, the kinetics and memory phenotype of CD8(+) T cell responses induced by alphavirus replicons are not well characterized. Furthermore, little is known how priming with alphavirus replicons affects booster immune responses induced by other vaccine modalities. We demonstrate that a single immunization with an alphavirus replicon, administered as viral particles or naked DNA, induced an antigen-specific CD8(+) T cell response that had a sharp peak, followed by a rapid contraction. Administering a homologous boost before contraction had occurred did not further increase the response. In contrast, boosting after contraction when CD8(+) T cells had obtained a memory phenotype (based on CD127/CD62L expression), resulted in maintenance of CD8(+) T cells with a high recall capacity (based on CD27/CD43 expression). Increasing the dose of replicon particles promoted T effector memory (Tem) and inhibited T central memory (Tcm) development. Moreover, infection with a replicating alphavirus induced a similar distribution of CD8(+) T cells as the replicon vector. Lastly, the distribution of T cell subpopulations induced by a DNA-launched alphavirus replicon could be altered by heterologous boosts. For instance, boosting with a poxvirus vector (MVA) favored expansion of the Tem compartment. In summary, we have characterized the antigen-specific CD8(+) T cell response induced by alphavirus replicon vectors and demonstrated how it can be altered by homologous and heterologous boost immunizations.Alphavirus replicons are promising vaccine candidates against a number of diseases and are by themselves developed as vaccines against for example chikungunya virus infection. Replicons are also considered to be used for priming followed by booster immunization using different vaccine modalities. In order to rationally design prime-boost immunization schedules with these vectors, characterization of the magnitude and phenotype of CD8(+) T cell responses induced by alphavirus replicons is needed. Here, we demonstrate how factors such as timing and dose affect the phenotype of the memory T cell populations induced by immunization with alphavirus replicons. These findings are important for designing future clinical trials with alphaviruses, as they can be used to tailor vaccination regimens in order to induce a CD8(+) T cell response that is optimal for control and/or clearance of a specific pathogen.
- Three-way interactions between mosquito population, viral strain and temperature underlying chikungunya virus transmission potential.
Zouache K, Fontaine A, Vega-Rua A, et al. Three-way interactions between mosquito population, viral strain and temperature underlying chikungunya virus transmission potential. [Journal Article]Proc Biol Sci 2014 Oct 7; 281(1792)AbstractPublisher Full TextInteractions between pathogens and their insect vectors in nature are under the control of both genetic and non-genetic factors, yet most studies on mosquito vector competence for human pathogens are conducted in laboratory systems that do not consider genetic and/or environmental variability. Evaluating the risk of emergence of arthropod-borne viruses (arboviruses) of public health importance such as chikungunya virus (CHIKV) requires a more realistic appraisal of genetic and environmental contributions to vector competence. In particular, sources of variation do not necessarily act independently and may combine in the form of interactions. Here, we measured CHIKV transmission potential by the mosquito Aedes albopictus in all combinations of six worldwide vector populations, two virus strains and two ambient temperatures (20°C and 28°C). Overall, CHIKV transmission potential by Ae. albopictus strongly depended on the three-way combination of mosquito population, virus strain and temperature. Such genotype-by-genotype-by-environment (G × G × E) interactions question the relevance of vector competence studies conducted with a simpler set of conditions. Our results highlight the need to account for the complex interplay between vectors, pathogens and environmental factors to accurately assess the potential of vector-borne diseases to emerge.
- Chikungunya Virus Transmission Found in the United States: US Health Authorities Brace for Wider Spread.
Kuehn BM Chikungunya Virus Transmission Found in the United States: US Health Authorities Brace for Wider Spread. [JOURNAL ARTICLE]JAMA 2014 Aug 13.Publisher Full Text
- Feeding host range of Aedes albopictus (Diptera: Culicidae) demonstrates its opportunistic host-seeking behavior in rural Singapore.
Kek R, Hapuarachchi HC, Chung CY, et al. Feeding host range of Aedes albopictus (Diptera: Culicidae) demonstrates its opportunistic host-seeking behavior in rural Singapore. [Journal Article, Research Support, Non-U.S. Gov't]J Med Entomol 2014 Jul; 51(4):880-4.AbstractPublisher Full TextAedes albopictus (Skuse) is a competent vector of arboviruses of public health importance, including dengue virus (DENV) and chikungunya virus viruses. Ae. albopictus is the primary vector of chikungunya virus in Singapore. However, despite being ubiquitous, it plays a secondary role in DENV transmission. The vectorial capacity of Ae. albopictus for DENV in field settings appears to be weak because dengue primarily occurs in Aedes aegypti (L.)-dominated, urban settings of the country. As host-seeking behavior is one of the determinants of vectorial capacity, we screened 6,762 female Ae. albopictus from rural, semiurban, and urban locations in Singapore for avian and nonavian bloodmeals using two polymerase chain reaction-sequencing assays developed in-house. The majority (83.2%, n = 79) of bloodmeals from rural and semiurban areas were from humans. However, Ae. albopictus was also found to feed on shrews, swine, dogs, cats, turtles, and multiple hosts in rural settings. In urban areas, all positive bloodmeals were from humans. There were no avian bloodmeals. Our findings testify that Ae. albopictus is highly anthropophagic even in rural settings, but become opportunistic in extremely low human abundance. This opportunistic feeding behavior warrants further investigations into the vectorial capacity of Ae. albopictus to assess its role in arbovirus transmission in endemic habitats.
- X-ray-Induced sterility in Aedes albopictus (Diptera: Culicidae) and male longevity following irradiation.
Yamada H, Parker AG, Oliva CF, et al. X-ray-Induced sterility in Aedes albopictus (Diptera: Culicidae) and male longevity following irradiation. [Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.]J Med Entomol 2014 Jul; 51(4):811-6.AbstractPublisher Full TextThe mosquito Aedes albopictus (Skuse, 1895) is a potent vector of several arboviral diseases, most notably chikungunya and dengue fever. In the context of the sterile insect technique (SIT), the sterilization of the male mosquitoes before their release can be achieved by gamma-ray irradiation. As gamma-ray irradiators are becoming increasingly problematic to purchase and transport, the suitability of an X-ray irradiator as an alternative for the sterilization of Ae. albopictus males was studied. The sterilization of up to 200,000 pupae at one time can be achieved with relative ease, and the sterility results obtained were comparable with those achieved by gamma irradiation, where 99% sterility is induced with a dose of 40 Gy. A significant reduction of longevity was observed in the latter stages of the males' life after irradiation treatments, especially at doses > 40 Gy, which is consistent with the negative effects on longevity induced by similar radiation doses using gamma rays. Females irradiated at 40 Gy were not only 100% sterile, but also failed to oviposit entirely, i.e., all of the females laid 0 eggs. Overall, it was found that the X-ray irradiator is generally suitable for the sterilization process for sterile insect technique programs, as it showed a high processing capacity, practicality, high effectiveness, and reproducibility.