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A sero-epidemiological study of arboviral fevers in Djibouti, Horn of Africa.

Andayi F, Charrel RN, Kieffer A, Richet H, Pastorino B, Leparc-Goffart I, Ahmed AA, Carrat F, Flahault A, de Lamballerie X - PLoS Negl Trop Dis (2014)

Bottom Line: However, there is a limited recent information regarding arbovirus circulation, and the associated risk predictors to human exposure are largely unknown.The detection of limited virus circulation was followed by a significant Chikungunya outbreak a few months after our study.Overall, most of the arboviral cases' predictors were statistically best described by the individuals' housing space and neighborhood environmental characteristics, which correlated with the ecological actors of their respective transmission vectors' survival in the local niche.

View Article: PubMed Central - PubMed

Affiliation: Aix Marseille Université, IRD French Institute of Research for Development, EHESP French School of Public Health, EPV UMR_D 190 "Emergence des Pathologies Virales", Marseille, France.

ABSTRACT
Arboviral infections have repeatedly been reported in the republic of Djibouti, consistent with the fact that essential vectors for arboviral diseases are endemic in the region. However, there is a limited recent information regarding arbovirus circulation, and the associated risk predictors to human exposure are largely unknown. We performed, from November 2010 to February 2011 in the Djibouti city general population, a cross-sectional ELISA and sero-neutralisation-based sero-epidemiological analysis nested in a household cohort, which investigated the arboviral infection prevalence and risk factors, stratified by their vectors of transmission. Antibodies to dengue virus (21.8%) were the most frequent. Determinants of infection identified by multivariate analysis pointed to sociological and environmental exposure to the bite of Aedes mosquitoes. The population was broadly naïve against Chikungunya (2.6%) with risk factors mostly shared with dengue. The detection of limited virus circulation was followed by a significant Chikungunya outbreak a few months after our study. Antibodies to West Nile virus were infrequent (0.6%), but the distribution of cases faithfully followed previous mapping of infected Culex mosquitoes. The seroprevalence of Rift valley fever virus was 2.2%, and non-arboviral transmission was suggested. Finally, the study indicated the circulation of Toscana-related viruses (3.7%), and a limited number of cases suggested infection by tick-borne encephalitis or Alkhumra related viruses, which deserve further investigations to identify the viruses and vectors implicated. Overall, most of the arboviral cases' predictors were statistically best described by the individuals' housing space and neighborhood environmental characteristics, which correlated with the ecological actors of their respective transmission vectors' survival in the local niche. This study has demonstrated autochthonous arboviral circulations in the republic of Djibouti, and provides an epidemiological inventory, with useful findings for risk mapping and future prevention and control programs.

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A map of the study area, Djibouti city, horn of Africa, showing the spatial distribution of households by Quartier(location) in the four administrative districts.
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pntd-0003299-g001: A map of the study area, Djibouti city, horn of Africa, showing the spatial distribution of households by Quartier(location) in the four administrative districts.

Mentions: The study was conducted in four administrative districts of Djibouti city, Republic of Djibouti, which is one of the 22 member states of the WHO Eastern Mediterranean region [20]. It is situated in the horn of Africa, at the Gulf of Eden of the Red Sea, bordering Somalia, Ethiopia, and Eritrea. It covers 23,200 km2 with 818,159 inhabitants, with majority of them, 70.6% (577,933) residing in urban areas [21]. Of those who live in urban, the largest proportion, 58.1% (475,322) are inhabitants of the capital, Djibouti city. Eco-geographically, the country is largely arid and semi arid, with perennial flooding during winter (November to April) and prolonged summers for the rest of the year. Fig. 1 shows an illustrative map of the study area, Djibouti city, together with the spatial distribution of participating households by Quartier (location) in the four administrative districts. The District 1 hosts the city center and there is a progressive decline in the urbanization, from District 2 towards District 4.


A sero-epidemiological study of arboviral fevers in Djibouti, Horn of Africa.

Andayi F, Charrel RN, Kieffer A, Richet H, Pastorino B, Leparc-Goffart I, Ahmed AA, Carrat F, Flahault A, de Lamballerie X - PLoS Negl Trop Dis (2014)

A map of the study area, Djibouti city, horn of Africa, showing the spatial distribution of households by Quartier(location) in the four administrative districts.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263616&req=5

pntd-0003299-g001: A map of the study area, Djibouti city, horn of Africa, showing the spatial distribution of households by Quartier(location) in the four administrative districts.
Mentions: The study was conducted in four administrative districts of Djibouti city, Republic of Djibouti, which is one of the 22 member states of the WHO Eastern Mediterranean region [20]. It is situated in the horn of Africa, at the Gulf of Eden of the Red Sea, bordering Somalia, Ethiopia, and Eritrea. It covers 23,200 km2 with 818,159 inhabitants, with majority of them, 70.6% (577,933) residing in urban areas [21]. Of those who live in urban, the largest proportion, 58.1% (475,322) are inhabitants of the capital, Djibouti city. Eco-geographically, the country is largely arid and semi arid, with perennial flooding during winter (November to April) and prolonged summers for the rest of the year. Fig. 1 shows an illustrative map of the study area, Djibouti city, together with the spatial distribution of participating households by Quartier (location) in the four administrative districts. The District 1 hosts the city center and there is a progressive decline in the urbanization, from District 2 towards District 4.

Bottom Line: However, there is a limited recent information regarding arbovirus circulation, and the associated risk predictors to human exposure are largely unknown.The detection of limited virus circulation was followed by a significant Chikungunya outbreak a few months after our study.Overall, most of the arboviral cases' predictors were statistically best described by the individuals' housing space and neighborhood environmental characteristics, which correlated with the ecological actors of their respective transmission vectors' survival in the local niche.

View Article: PubMed Central - PubMed

Affiliation: Aix Marseille Université, IRD French Institute of Research for Development, EHESP French School of Public Health, EPV UMR_D 190 "Emergence des Pathologies Virales", Marseille, France.

ABSTRACT
Arboviral infections have repeatedly been reported in the republic of Djibouti, consistent with the fact that essential vectors for arboviral diseases are endemic in the region. However, there is a limited recent information regarding arbovirus circulation, and the associated risk predictors to human exposure are largely unknown. We performed, from November 2010 to February 2011 in the Djibouti city general population, a cross-sectional ELISA and sero-neutralisation-based sero-epidemiological analysis nested in a household cohort, which investigated the arboviral infection prevalence and risk factors, stratified by their vectors of transmission. Antibodies to dengue virus (21.8%) were the most frequent. Determinants of infection identified by multivariate analysis pointed to sociological and environmental exposure to the bite of Aedes mosquitoes. The population was broadly naïve against Chikungunya (2.6%) with risk factors mostly shared with dengue. The detection of limited virus circulation was followed by a significant Chikungunya outbreak a few months after our study. Antibodies to West Nile virus were infrequent (0.6%), but the distribution of cases faithfully followed previous mapping of infected Culex mosquitoes. The seroprevalence of Rift valley fever virus was 2.2%, and non-arboviral transmission was suggested. Finally, the study indicated the circulation of Toscana-related viruses (3.7%), and a limited number of cases suggested infection by tick-borne encephalitis or Alkhumra related viruses, which deserve further investigations to identify the viruses and vectors implicated. Overall, most of the arboviral cases' predictors were statistically best described by the individuals' housing space and neighborhood environmental characteristics, which correlated with the ecological actors of their respective transmission vectors' survival in the local niche. This study has demonstrated autochthonous arboviral circulations in the republic of Djibouti, and provides an epidemiological inventory, with useful findings for risk mapping and future prevention and control programs.

Show MeSH
Related in: MedlinePlus