title: Parasite burden in hamsters infected with two different strains of leishmania (Leishmania) infantum: "Leishman Donovan units" versus real-time PCR.
abstract: To develop and test new therapeutics and immune prophylaxis strategies for visceral leishmaniasis (VL), understanding tissue parasitism evolution after experimental infection with Leishmania infantum is important. Experimental infection in a hamster model (Mesocricetus auratus) reproduces several typical aspects of canine and human VL that are closely related to the inoculum's route. We quantified the parasitism in the liver and spleen of hamsters experimentally infected by various routes (intradermal, intraperitoneal, and intracardiac [IC]) and different strains of L. infantum (MHOM/BR/74/PP75 and Wild) and compared two different methodologies to evaluate tissue parasitism (Leishman Donovan units [LDU] and real-time qPCR). In addition, the quantification of specific total-IgG in the serum of uninfected and infected hamsters was determined by ELISA. The animals were followed for 1, 3, 6 and 9 months post-infection for survival analysis. We found that infection with the Wild strain by the IC route resulted in higher mortality. Positive antibody (IgG) responses were detected with higher peaks at 6 and 9 months in the IC group inoculated with PP75 strain. However, in animals infected with the Wild strain the IgG levels were elevated in all infected groups during all the time evaluated. We also observed by LDU analysis that the IC route lead to higher parasitism in the liver and spleen with both strains. Furthermore, qPCR showed higher sensitivity for identifying animals with low parasitic burden. In conclusion, qPCR can be useful for assessing parasitism in the spleen and liver of a hamster model infected with L. infantum independent of the route of infection, and this technique may become an essential tool for assessing parasite density in the hamster model after experimental treatment or immunization with potential vaccine candidates.
authors.affiliation: Laboratório de Imunopatologia, Núcleo de Pesquisas em Ciências Biológicas/NUPEB, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brasil.
authors.forename: Nádia das Dores
authors.initials: Nd
authors.lastname: Moreira
authors.forename: Juliana
authors.initials: J
authors.lastname: Vitoriano-Souza
authors.forename: Bruno Mendes
authors.initials: BM
authors.lastname: Roatt
authors.forename: Paula Melo de Abreu
authors.initials: PM
authors.lastname: Vieira
authors.forename: Henrique Gama
authors.initials: HG
authors.lastname: Ker
authors.forename: Jamille Mirelle
authors.initials: JM
authors.lastname: de Oliveira Cardoso
authors.forename: Rodolfo Cordeiro
authors.initials: RC
authors.lastname: Giunchetti
authors.forename: Cláudia Martins
authors.initials: CM
authors.lastname: Carneiro
authors.forename: Marta
authors.initials: M
authors.lastname: de Lana
authors.forename: Alexandre Barbosa
authors.initials: AB
authors.lastname: Reis
mesh_terms: D000818:Animals; D006224:Cricetinae / Q000097:blood / Q000469:parasitology*; D006801:Humans; D056724:Immunity, Humoral; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D018314:Leishmania infantum / Q000276:immunology / Q000302:isolation & purification*; D007898:Leishmaniasis, Visceral / Q000097:blood / Q000276:immunology / Q000469:parasitology* / Q000473:pathology; D008099:Liver / Q000276:immunology / Q000469:parasitology* / Q000473:pathology; D008297:Male; D060888:Real-Time Polymerase Chain Reaction; D013154:Spleen / Q000276:immunology / Q000469:parasitology* / Q000473:pathology
chemical_list: D007074:Immunoglobulin G