Seroepidemiological Study of Interepidemic Rift Valley Fever Virus Infection Among Persons with Intense Ruminant Exposure in Madagascar and Kenya

Gray, Gregory C.; Anderson, Benjamin D.; LaBeaud, A. Desirée; Heraud, Jean‐Michel; Fèvre, Eric M.; Andriamandimby, Soa Fy; Cook, Elizabeth A. J.; Saïdi, D.; Glanville, William A. de; Heil, Gary L.; Khan, Salah Ud‐Din; Muiruri, Samuel; Olive, Marie-Marie; Thomas, Lian F.; Merrill, Hunter R.; Merrill, Mary L. M.; Richt, Jüergen A.

doi:10.4269/ajtmh.15-0383

Cited by 21 publications

(18 citation statements)

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“…At first glance, the variation of RVF FOIs estimated from mid-1992 to mid-2014 is in accordance with the historical report of RVF transmission in Madagascar: high transmission during the 2008–09 outbreaks and low transmission outside this period12161718192021. Then, our results are consistent with the hypothesis of contrasted patterns of long-term RVFV enzootic circulation in the different Malagasy eco-regions.…”

Section: Discussionsupporting

confidence: 91%

“…The central Highlands are characterized, during the dry season, by a cold environment unfavorable for RVF vectors132930. Yet, recurrent RVFV circulation has been detected in cattle in mid-2009, 2010–2011 and in human in 2012 in this region171819. Finally, our estimations showed an unexpected FOI peak in mid-2002/mid-2003 in the northwestern and the Highlands regions.…”

Section: Discussionmentioning

confidence: 55%

“…Then, outbreaks occurred in two epidemic waves during the two consecutive rainy seasons of 2008 and 200912. The last RVF case was reported in March 2009 but recurrent circulation of the virus has since been detected in mid-2009, 2010–11 and 2012 on the Malagasy Highlands171819. Since few data are available on RVF circulation during the 1990–91 and 2008–09 outbreaks as well as during the inter-epizootic period (IEP), the dynamics of transmission of RVF in Madagascar and the epidemiological mechanisms underlying these dynamics remain unclear.…”

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confidence: 99%

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Reconstruction of Rift Valley fever transmission dynamics in Madagascar: estimation of force of infection from seroprevalence surveys using Bayesian modelling

Olive

Grosbois²,

Tran³

et al. 2017

Sci Rep

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The force of infection (FOI) is one of the key parameters describing the dynamics of transmission of vector-borne diseases. Following the occurrence of two major outbreaks of Rift Valley fever (RVF) in Madagascar in 1990–91 and 2008–09, recent studies suggest that the pattern of RVF virus (RVFV) transmission differed among the four main eco-regions (East, Highlands, North-West and South-West). Using Bayesian hierarchical models fitted to serological data from cattle of known age collected during two surveys (2008 and 2014), we estimated RVF FOI and described its variations over time and space in Madagascar. We show that the patterns of RVFV transmission strongly differed among the eco-regions. In the North-West and Highlands regions, these patterns were synchronous with a high intensity in mid-2007/mid-2008. In the East and South-West, the peaks of transmission were later, between mid-2008 and mid-2010. In the warm and humid northwestern eco-region favorable to mosquito populations, RVFV is probably transmitted all year-long at low-level during inter-epizootic period allowing its maintenance and being regularly introduced in the Highlands through ruminant trade. The RVF surveillance of animals of the northwestern region could be used as an early warning indicator of an increased risk of RVF outbreak in Madagascar.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 55%

mentioning

confidence: 99%

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Reconstruction of Rift Valley fever transmission dynamics in Madagascar: estimation of force of infection from seroprevalence surveys using Bayesian modelling

Olive

Grosbois²,

Tran³

et al. 2017

Sci Rep

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“…We showed that the RVFV IgG prevalence for all three counties investigated was 36.4%. This is in the higher range compared to previous studies from Northeastern Kenya [43][44][45], and 15-25% in 2009-2012 [1,23,46,47]. Our findings showed males were at a significantly higher risk of infection by RVFV than females, and increased age was associated with higher RVF IgG prevalence.…”

Section: Discussioncontrasting

confidence: 60%

High risk for human exposure to Rift Valley fever virus in communities living along livestock movement routes: A cross-sectional survey in Kenya

et al. 2020

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IntroductionMultiple outbreaks of Rift Valley Fever (RVF) with devastating effects have occurred in East Africa. These outbreaks cause disease in both livestock and humans and affect poor households most severely. Communities living in areas practicing nomadic livestock movement may be at higher risk of infection. This study sought to i) determine the human exposure to Rift Valley fever virus (RVFV) in populations living within nomadic animal movement routes in Kenya; and ii) identify risk factors for RVFV infection in these communities. MethodsA cross-sectional descriptive study design was used. Samples were collected from the year 2014 to 2015 in a community-based sampling exercise involving healthy individuals aged �18 years from Isiolo, Tana River, and Garissa counties. In total, 1210 samples were screened by ELISA for the presence of immunoglobulin IgM and IgG antibodies against RVFV. Positive results were confirmed by plaque reduction neutralization test. ResultsOverall, IgM and IgG prevalence for all sites combined was 1.4% (95% CI 0.8-2.3%) and 36.4% (95% CI 33.8-39.2%), respectively. Isiolo County recorded a non-significant higher IgG prevalence of 38.8% than Garissa 35.9% and Tana River 32.2% (Chi square = 2.5, df = 2, p = 0.287). Males were significantly at higher risk of infection by RVFV than females (OR = 1.67, 95% CI 1.17-2.39, p<0.005). Age was significantly associated with RVFV infection (Wald Chi = 94.2, df = 5, p<0.0001). Individuals who had regular contact with cattle (OR = 1.38, 95%CI 1.01-1.89) and donkeys (OR = 1.38, 95%CI 1.14-1.67), or contact with PLOS Neglected Tropical Diseases | https://doi.The grants were awarded to M. Evander, R. Sang and C. Ahlm. The funders had no role in the study design, data collection and animals through birthing (OR = 1.69, 95%CI 1.14-2.51) were significantly at a greater risk of RVFV infection than those who did not. ConclusionThis study demonstrated that although the Isiolo County has been classified as being at medium risk for RVF, virus infection appeared to be as prevalent in humans as in Tana River and Garissa, which have been classified as being at high risk. Populations in these counties live within nomadic livestock movement routes and therefore at risk of being exposed to the RVFV. Interventions to control RVFV infections therefore, should target communities living along livestock movement pathways. Author summaryRift Valley fever (RVF) is a neglected mosquito-borne zoonotic disease that causes major outbreaks and economic harm to human and ruminants health leading to increased poverty within affected communities. RVF is caused by RVF virus (RVFV) affecting humans and a wide range of ruminants. The virus is transmitted through bites from mosquitoes and exposure to blood, body fluids, or tissues of infected ruminants. It was first isolated in Kenya in 1930 and several outbreaks have been recorded in many countries in sub-Saharan Africa. We studied pastoralist communities living along livestock migratory routes. Migratory livestock do move long distan...

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“…Despite a recurrent circulation of RVFV (Andriamandimby et al, 2010;Ratovonjato et al, 2011;Gray et al, 2015) and the abundance of potential vectors (Tantely et al, 2015), no study on vector competence has been carried out in Madagascar to date. To better understand the mechanisms behind the maintenance and transmission of RVFV in Madagascar, the present study was designed to evaluate the vector competence of Cx.…”

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confidence: 99%

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

Nepomichene

Raharimalala

Andriamandimby

et al. 2018

Medical Vet Entomology

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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.

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Seroepidemiological Study of Interepidemic Rift Valley Fever Virus Infection Among Persons with Intense Ruminant Exposure in Madagascar and Kenya

Cited by 21 publications

References 22 publications

Reconstruction of Rift Valley fever transmission dynamics in Madagascar: estimation of force of infection from seroprevalence surveys using Bayesian modelling

Reconstruction of Rift Valley fever transmission dynamics in Madagascar: estimation of force of infection from seroprevalence surveys using Bayesian modelling

High risk for human exposure to Rift Valley fever virus in communities living along livestock movement routes: A cross-sectional survey in Kenya

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

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