Rift Valley fever in West Africa: the role of space in endemicity.
Rift Valley fever is an endemic vector-borne disease in West Africa, which mainly affects domestic ruminants and occasionally humans. The aetiological mechanisms of its endemicity remain under debate. We used a simple spatially explicit model to assess the possibility of endemicity without wild animals providing a permanent virus reservoir. Our model takes into account the vertical transmission in some mosquito species, the rainfall-driven emergence of their eggs and local and distant contacts because of herd migration. Endemicity without such a permanent virus reservoir would be impossible in a single site except when there is a strictly periodic rainfall pattern; but it would be possible when there are herd movements and sufficient inter-site variability in rainfall, which drives mosquito emergence.
Favier
Charly
C
LOCEAN, Université P&M Curie, Paris, France. favier@isem-univ-montp2.fr
Chalvet-Monfray
Karine
K
Sabatier
Philippe
P
Lancelot
Renaud
R
Fontenille
Didier
D
Dubois
Marc A
MA
D000330:Aedes / Q000821:virology; D000354:Africa, Western / Q000453:epidemiology; D000818:Animals; D004197:Disease Reservoirs; D019353:Endemic Diseases; D006801:Humans; D018445:Infectious Disease Transmission, Vertical; D007303:Insect Vectors; D008954:Models, Biological; D011157:Population Dynamics; D011891:Rain; D012295:Rift Valley Fever / Q000453:epidemiology* / Q000635:transmission*; D013269:Stochastic Processes; D015047:Zoonoses / Q000453:epidemiology