The potential role of rodents in the enzootic cycle of Rift Valley fever virus in Senegal

Wild rodents (214) of fourteen species were trapped at seven sites in Seneg al. Arvicanthis niloticus and Mastomys erythroleucus were among the most fr equently collected species (77.2% of total capture). All rodents were exami ned for the presence of anti-Rift Valley fever virus (RVFV) antibody; the p revalence over all sampled species was 3.8%, varying widely with respect to species and location. Four of 14 species of rodents were found to have ant i-RVFV antibodies: Rattus rattus (one positive of two tested) Mastomys hube rti (13.5%), A. niloticus (4.3%), and M. erythroleucus (2.4%). The highest prevalence of anti-RVFV antibody was recorded within the enzootic area of t he Senegal River delta, at Richard Toll (9.6%). A. niloticus and M. erythro leucus and a strain of laboratory-bred mice were experimentally inoculated with two strains of RVFV and examined for viremia, illness, seroconversion and mortality. A. niloticus and M. erythroleucus demonstrated a limited res istance to infection, thus potentially allowing for the replication of viru s in these animals and making these species possible candidates as hosts in the maintenance cycle of RVFV in nature. (C) 2000 Editions scientifiques e t medicales Elsevier SAS.