The spiny rat Proechimys guyannensis (Rodentia: Echimydae) fails to respond to intradermal inoculation with Leishmania (Viannia) braziliensis

Abstract

Leishmaniasis a disease of worldwide occurrence is caused by protozoa of the Leishmania genus. In Brazil, Leishmania (Viannia) braziliensis is the main parasite responsible for the American cutaneous leishmaniasis. Main hosts of this protozoa are small wild mammals particularly marsupials and rodents. The aim of this study was to evaluate if spiny rat Proechimys guyannensis (Rodentia: Echimydae) has role in the cycle of the American cutaneous leishmaniasis caused by L. (V.) braziliensis. Thus, promastigotes (the flagellate stage) of Leishmania (Viannia) braziliensis were used to inoculate seven spiny rats (Proechimys guyannensis). After inoculated intradermal at the ear pinna, nose and plantar pad, the rats were monitored for 180 days. Tissue samples collected at 90 and 180 days from the rats proved to be negative for the presence of genetic material from the parasite. After euthanasia, the protozoa also failed to growth in culture medium containing tissue samples collected from the rats showing that there was no infection. These results fail to prove that spiny rat has a role in the cycle of the American cutaneous leishmaniasis caused by L. (V.) braziliensis. KEYWORDS: Leishmaniasis, American cutaneous leishmaniasis, rodents, reservoirs O rato espinhoso Proechimys guyannensis (Rodentia: Echimydae) falhou para inoculação intradérmica com Leishmania (Viannia) braziliensis. RESUMOA leishmaniose é uma doença de ocorrência mundial causada por protozoários do gênero Leishmania. No Brasil, a Leishmania (Viannia) braziliensis é o principal parasita responsável pela leishmaniose tegumentar americana. Os principais hospedeiros deste protozoário são pequenos mamíferos selvagens em particular marsupiais e roedores. O objetivo deste estudo foi avaliar o papel do rato espinhoso Proechimys guyannensis (Rodentia: Echimydae) no ciclo da leishmaniose tegumentar americana. Para isto, formas promastigotas (estágio flagelado) de Leishmania (Viannia) braziliensis foram inoculadas em sete ratos espinhosos (Proechimys guyannensis). Após a inoculação intradérmica no pavilhão auricular, focinho e área plantar, os ratos foram monitorizados durante 180 dias. Amostras de tecido colhidas aos 90 e 180 dias dos ratos revelaram-se negativas para a presença de material genético do parasita. Após eutanásia, tecidos coletados dos ratos também falharam para crescimento em meio de cultura demonstrando que não houve infecção. Estes resultados demonstram que o rato espinhoso não tem papel no ciclo da leishmaniose tegumentar americana causada por L. (V.) braziliensis. PALAVRAS-CHAVE: Leishmaniose, leishmaniose tegumentar americana, roedores, reservatórios. ) in association. A fragment of 1 cm 2 was collected from the lesion edge. The fragment was divided into two parts -one for performing the PCR, and the other for culture in NNN-LIT (Novy MacNeal Nicolle -Liver Infusion Tryptose) medium, increased 10% Fetal Bovine Serum, which served as a source of promastigotes and culture for the parasite. In their stationary growth phase the two strains...

Characterization of the estrous cycle in the Amazon spiny rat (Proechimys guyannensis)

“…P. guyannensis (É. Geoffroy, 1803), an Amazon rodent of suborder Hystricomorpha (Simpson, 1945; Reig et al., 1979), is of interest to biomedical researches because of its physiological responses; it is not infected by several pathogens (Lainson and Shaw, 1975) and exhibits an endogenous antiepileptogenic mechanism that can ensures that this rodent can be employed as a model for studying epilepsy (Arida et al., 2005). Most of the studies on Proechimys have been performed in males rather than in females (Fabene et al., 2001; Arida et al., 2005; Passos et al., 2015), perhaps to avoid irregular responses found in females because of hormonal interaction. Despite this variability, knowledge about females Proechimys is relevant, not just to describe the species but also to explain the interaction between sex hormones and physiological responses.…”