COHORT STUDY ON CANINE EMIGRATION AND LEISHMANIA INFECTION IN AN ENDEMIC AREA FOR AMERICAN VISCERAL LEISHMANIASIS - IMPLICATIONS FOR THE DISEASE-CONTROL

American visceral leishmaniasis is a main public health matter in Braz il. Since dogs have been incriminated as the main urban reservoir of A VL agent Leishmania chagasi, a cohort study aimed at understanding the dynamics of the canine infection was carried out in Jequie-an endemic community in the Northeast of Brazil. The inhabited urban and periurb an areas of Jequie were divided into 140 clusters of 0.25 km(2). All 1 681 dogs domiciled in 34 randomly selected clusters were screened for Leishmania antibodies in an enzyme-linked immunosorbent assay. After t he seropositive dogs were painlessly eliminated, a cohort of 1286 sero negative dogs was followed up for 18 months, yielding a total of 1739. 7 dog-years. The overall incidence of Leishmania infection, as assesse d by the detection of Leishmania antibodies in blood samples collected every six months, was 6.55 cases/100 dog-years (95% confidence interv al; CI 6.04-7.26). Two subsets of clusters, with 0.70 and 1.35 relativ e risks of infection, were identified. The annual emigration rate was 2.26 cases/100 dog-years (95% CI 1.86-2.66). The implications of these findings for the control of American visceral leishmaniasis are discu ssed. (C) 1998 Elsevier Science B.V. All rights reserved.