Vector competence of Culex antennatus and Anopheles coustani mosquitoes for Rift Valley fever virus in Madagascar.

Culex antennatus (Diptera: Culicidae), Anopheles coustani (Diptera: Culicidae) and Anopheles squamosus/cydippis were found to be infected with Rift Valley fever virus (RVFV) during an epidemic that occurred in 2008 and 2009 in Madagascar. To understand the roles played by Cx. antennatus and An. coustani in virus maintenance and transmission, RVFV vector competence was assessed in each species. Mosquito body parts and saliva of mosquitoes that fed on RVFV-infected blood were tested for RVFV using real-time quantitative polymerase chain reaction (RT-qPCR) assays. Overall, viral RNA was detected in body parts and saliva at 5 days post-infection (d.p.i.) in both species. At 5 d.p.i., infection rates were 12.5% (3/24) and 15.8% (6/38), disseminated infection rates were 100% (3/3) and 100% (6/6), transmission rates were 33.3% (1/3) and 83.3% (5/6), and transmission efficiencies were 4.2% (1/24) and 13.2% (5/38) in Cx. antennatus and An. coustani, respectively. Although RVFV detected in saliva did not propagate on to Vero cells, these results support potential roles for these two mosquito species in the transmission of RVFV.

Excess mortality associated with the 2009 A(H1N1)v influenza pandemic in Antananarivo, Madagascar.

It is difficult to assess the mortality burden of influenza epidemics in tropical countries. Until recently, the burden of influenza was believed to be negligible in Africa. We assessed the impact of the 2009 influenza epidemic on mortality in Madagascar by conducting Poisson regression analysis on mortality data from the deaths registry, after the first wave of the 2009 A(H1N1) virus pandemic. There were 20% more human deaths than expected in Antananarivo, Madagascar in November 2009, with excess mortality in the ⩾50 years age group (relative risk 1·41). Furthermore, the number of deaths from pulmonary disease was significantly higher than the number of deaths from other causes during this pandemic period. These results suggest that the A(H1N1) 2009 virus pandemic may have been accompanied by an increase in mortality.

Seasonal gaps in measles vaccination coverage in Madagascar.

INTRODUCTION: Measles elimination depends on the successful deployment of measles containing vaccine. Vaccination programs often depend on a combination of routine and non-routine services, including supplementary immunization activities (SIAs) and vaccination weeks (VWs), that both aim to vaccinate all eligible children regardless of vaccination history or natural infection. Madagascar has used a combination of these activities to improve measles coverage. However, ongoing massive measles outbreak suggests that the country was in a "honeymoon" period and that coverage achieved needs to be re-evaluated. Although healthcare access is expected to vary seasonally in low resources settings, little evidence exists to quantify temporal fluctuations in routine vaccination, and interactions with other immunization activities. METHODS: We used three data sources: national administrative data on measles vaccine delivery from 2013 to 2016, digitized vaccination cards from 49 health centers in 6 health districts, and a survey of health workers. Data were analyzed using linear regressions, analysis of variance, and t-tests. FINDINGS: From 2013 to 2016, the footprint of SIAs and VWs is apparent, with more doses distributed during the relevant timeframes. Routine vaccination decreases in subsequent months, suggesting that additional activities may be interfering with routine services. The majority of missed vaccination opportunities occur during the rainy season. Health facility organization and shortage of vaccine contributed to vaccination gaps. Children born in June were the least likely to be vaccinated on time. DISCUSSION: Evidence that routine vaccination coverage varies over the year and is diminished by other activities suggests that maintaining routine vaccination during SIAs and VWs is a key direction for strengthening immunization programs, ensuring population immunity and avoiding future outbreaks. FUNDING: Wellcome Trust Fund, Burroughs Wellcome Fund, Gates Foundation, National Institutes of Health.

West Nile virus infection in horses, Indian ocean.

The circulation of West Nile virus (WNV) in horses was investigated in the Southwest Indian ocean. In 2010, blood samples were collected from a total of 303 horses originating from Madagascar, Mauritius, Reunion and the Seychelles and tested for WNV-specific antibodies. An overall seroprevalence of 27.39% was detected in the Indian Ocean with the highest WNV antibody prevalence of 46.22% (95% CI: [37.4-55.2%]) in Madagascar. The age and origin of the horses were found to be associated with the WNV infection risk. This paper presents the first seroprevalence study investigating WN fever in horses in the Southwest Indian Ocean area and indicates a potential risk of infection for humans and animals. In order to gain a better understanding of WN transmission cycles, WNV surveillance needs to be implemented in each of the countries.

Correction: Temporal Patterns of Influenza A and B in Tropical and Temperate Countries: What Are the Lessons for Influenza Vaccination?

[This corrects the article DOI: 10.1371/journal.pone.0152310.].

Altered balance between Th17 and Th1 cells at mucosal sites predicts AIDS progression in simian immunodeficiency virus-infected macaques.

Loss of CD4(+) T cells in the gut is necessary but not sufficient to cause AIDS in animal models, raising the possibility that a differential loss of CD4(+) T-cell subtypes may be important. We found that CD4(+) T cells that produce interleukin (IL)-17, a recently identified lineage of effector CD4(+) T-helper cells, are infected by SIV(mac251)in vitro and in vivo, and are found at lower frequency at mucosal and systemic sites within a few weeks from infection. In highly viremic animals, Th1 cells predominates over Th17 T cells and the frequency of Th17 cells at mucosal sites is negatively correlated with plasma virus level. Because Th17 cells play a central role in innate and adaptive immune response to extracellular bacteria, our finding may explain the chronic enteropathy in human immunodeficiency virus (HIV) infection. Thus, therapeutic approaches that reconstitute an adequate balance between Th1 and Th17 may be beneficial in the treatment of HIV infection.

Association of Tonate virus (subtype IIIB of the Venezuelan equine encephalitis complex) with encephalitis in a human.

Tonate virus, subtype IIIB of the Venezuelan equine encephalitis (VEE) complex, was first isolated in 1973 in French Guiana, South America. However, very little is known about its pathogenicity; it was considered to be responsible for only mild dengue-like syndromes. In 1998, a 2-month-old boy living along the Oyapock river in French Guiana was hospitalized for fever and generalized status myoclonus, and despite treatment the patient died 72 h after admission. Testing showed the presence of IgM specific for viruses of the VEE complex. A sensitive seminested polymerase chain reaction derived from a previous study was developed to detect viruses from the VEE complex, since no virus could be recovered from clinical specimens cultured on mosquito cells or from intracerebral inoculation into newborn mice. The genome of a virus from the VEE complex was detected in postmortem brain biopsies, and Tonate virus was identified by direct sequencing. This is the first reported case of human encephalitis due to Tonate virus.

Determination of natural versus laboratory human infection with Mayaro virus by molecular analysis.

A laboratory worker developed clinical signs of infection with Mayaro virus (Togaviridae), an arbovirus of South and Central America, 6 days after preparation of Mayaro viral antigen and 10 days after a trip to a rain forest. There was no evidence of skin lesions during the antigen preparation, and level 3 containment safety measures were followed. Therefore, molecular characterization of the virus was undertaken to identify the source of infection. RT-PCR and DNA sequence comparisons proved the infection was with the laboratory strain. Airborne Mayaro virus contamination is thus a hazard to laboratory personnel.

First case of yellow fever in French Guiana since 1902.

The first case of yellow fever in French Guiana since 1902 was reported in March 1998. The yellow fever virus genome was detected in postmortem liver biopsies by seminested polymerase chain reaction. Sequence analysis showed that this strain was most closely related to strains from Brazil and Ecuador.

Lipid products of phosphoinositide 3-kinase and phosphatidylinositol 4',5'-bisphosphate are both required for ADP-dependent platelet spreading.

We have shown previously that ADP released upon platelet adhesion mediated by alphaIIb beta3 integrin triggers accumulation of phosphatidylinositol 3',4'-bisphosphate (PtdIns-3,4-P2) (Gironcel, D. , Racaud-Sultan, C., Payrastre, B., Haricot, M., Borchert, G., Kieffer, N., Breton, M., and Chap, H. (1996) FEBS Lett. 389, 253-256). ADP has also been involved in platelet spreading. Therefore, in order to study a possible role of phosphoinositide 3-kinase in platelet morphological changes following adhesion, human platelets were pretreated with specific phosphoinositide 3-kinase inhibitors LY294002 and wortmannin. Under conditions where PtdIns-3, 4-P2 synthesis was totally inhibited (25 microM LY294002 or 100 nM wortmannin), platelets adhered to the fibrinogen matrix, extended pseudopodia, but did not spread. Moreover, addition of ADP to the medium did not reverse the inhibitory effects of phosphoinositide 3-kinase inhibitors on platelet spreading. Although synthetic dipalmitoyl PtdIns-3,4-P2 and dipalmitoyl phosphatidylinositol 3',4', 5'-trisphosphate restored only partially platelet spreading, phosphatidylinositol 4',5'-bisphosphate (PtdIns-4,5-P2) was able to trigger full spreading of wortmannin-treated adherent platelets. Following 32P labeling of intact platelets, the recovery of [32P]PtdIns-4,5-P2 in anti-talin immunoprecipitates from adherent platelets was found to be decreased upon treatment by wortmannin. These results suggest that the lipid products of phosphoinositide 3-kinase are required but not sufficient for ADP-induced spreading of adherent platelets and that PtdIns-4,5-P2 could be a downstream messenger of this signaling pathway.

Suburban transmission of Q fever in French Guiana: evidence of a wild reservoir.

The annual incidence of Q fever in French Guiana was found to have increased in 1996 and was 37/100,000 population over the last 4 years. Subsequent investigations in Cayenne and its suburbs indicated that a wild reservoir of the bacteria was responsible for the epidemiologic pattern. A case-control study showed that residence near a forest and occupations and activities that result in exposure to aerosols of dusts from the soil are risk factors for Q fever. By means of time-series analysis, a strong positive correlation between rainfall and the incidence of Q fever with a time lag of 1-3 months was found. The spatial distribution of the cases showed that transmission occurs widely throughout greater Cayenne, which is incompatible with a pinpoint source of contamination. Transmission from livestock and dissemination of the bacteria by the wind appeared to be unlikely, which strengthens the hypothesis that a wild reservoir is responsible for transmission.