A laboratory model of canine leishmaniasis: the inoculation of dogs withLeishmania infantumpromastigotes from midguts of experimentally infected phlebotomine sandflies

Abstract

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

Evaluation of parasitological examination, kDNA polymerase chain reaction and rK39-based immunochromatography for the diagnosis of visceral leishmaniasis in seropositive dogs from the screening-culling program in Brazil

“…The tendency towards higher co-positivity percentages in symptomatic dogs compared with asymptomatic dogs, which was consistently observed in this study, agrees with the literature for several diagnostic tests 2,3,[34][35][36][37][38][39] . Depending on the assay, this may be related to higher antibody titers or to higher parasite loads in clinically ill dogs 2 .…”

Canine experimental infection: intradermal inoculation of Leishmania infantum promastigotes

“…The fact that no parasites were found after 24 h indicates that this phenomenon is different from the one observed after inoculation of promastigotes collected from the vector in which all dogs developed skin lesions (Killick-Kendrick et al 1994). The existence of immunological response in all inoculated dogs and the presence of parasites in the popliteal lymph node (confirmed in one case), may suggest that macrophages cells could play a role as carriers for the dissemination of parasites.…”

“…Indeed, a possible role of sand fly saliva in the formation of inoculation chancres could explain the absence of leishmaniome in the present study. However this role has not been proved, as verified by Killick-Kendrick et al (1994). Although, the presence of sand flies salivary glands in the experimental inoculation of different species of Leishmania in the rodent model seems to increase the severity of infection (Titus & Ribeiro 1988, Samuelson et al 1991, Theodos et al 1991, Lima & Titus 1996, Belkaid et al 1998).…”

“…Furthermore the period of incubation in dogs is usually larger than the period of observation in this study. In experimental infections by L. infantum either through the bite of a sand fly (Rioux et al 1979) or by intradermal injections of metacyclic promastigotes from sand flies (Killick-Kendrick et al 1994) the incubation period was from 16 to 24 months. Studies carried out in naturally infected dogs indicate that canine leishmaniasis has a prolonged asymptomatic period (Adler & Theodor 1932, Abranches et al 1991.…”

Clinical, Parasitologic, and Immunologic Evolution in Dogs Experimentally Infected with Sand Fly-Derived Leishmania chagasi Promastigotes

“…[3][4][5] Experimental infections of dogs have been carried out using a wide range of strategies that included the use of cultured promastigotes [6][7][8] or tissue-derived amastigotes. 6,7,9 Studies have used numbers of parasites that ranged from a few thousand to several million, delivered by the intradermal [10][11][12][13] or intravenous routes. 6,[14][15][16][17] Some of these inoculations included an extract of Lutzomyia longipalpis salivary glands in an unsuccessful attempt to increase parasite pathogenicity.…”