No abstract

Assessment of the resilience of canine leishmaniasis to control or, more ambitiously, the effort needed to eradicate infection, requires an estimate of the basic case reproduction number (R0). This paper applies the theoretical results of Hasibeder, Dye & Carpenter (1992) to data from a cross-sectional survey on the Maltese island of Gozo in which dogs of known age, sex and occupation (pet, guard etc) were subjected to three different serological tests for the presence of specific antibody (IFAT, DAT and ELISA). Difficulties in interpreting these test results, and hence of determining the proportion of dogs infected, present the main obstacle to estimating R0: estimates are critically dependent on the choice of threshold separating seropositives from seronegatives. The data do, however, allow a robust comparative analysis of risk which shows that the force of infection experienced by working dogs is about three times higher than that of pet dogs, a degree of non-homogeneous contact which actually has little effect on estimates of R0. We suggest a cautious point estimate of R0 congruent to 11, and comment briefly on its significance for leishmaniasis control.

Summary :Twenty-five dogs (beagles) were infected with Leishmania infantum by the intradermal inoculation of an estimated 5-8,000 metacyclic promastigotes harvested from the midguts of 320 experimentally T here are two main difficulties in testing vaccines against canine leishmaniasis experimentally in dogs. The first is that dogs appear generally to respond to infection in one of two ways because of inherent differences in susceptibility (Lanotte et al., 1979; Vidor et al., 1991;Dye et al., 1992; Cabrai et al., 1992; Pinelli et al., 1994) which are evident by the immune response. A cell mediated immunity is associated with inapparent infections, whereas there is no evidence of protection by circulating antibodies (Liew and O'Donnell, 1993) constantlyhigh levels of which usually indicate susceptibility