Sex Matters: Male Hamsters Are More Susceptible to Lethal Infection with Lower Doses of Pathogenic Leptospira than Female Hamsters

Abstract

A somewhat contradictory published body of evidence suggests that sex impacts severity outcomes of human leptospirosis. In this study, we used an acute animal model of disease to analyze leptospirosis in male and female hamsters infected side by side with low but increasing doses of serovar Copenhageni. We found that male hamsters were considerably more susceptible to leptospirosis, given that only 6.3% survived infection, whereas 68.7% of the females survived the same infection doses. In contrast to the females, male hamsters had high burdens of in kidney and high histopathological scores after exposure to low infection doses (∼10 bacteria). In hamsters infected with higher doses of (∼10 bacteria), differences in pathogen burdens as well as cytokine and fibrosis transcript levels in kidney were not distinct between sexes. Our results indicate that male hamsters infected with are more susceptible to severe leptospirosis after exposure to lower infectious doses than females.

Three Leptospira Strains From Western Indian Ocean Wildlife Show Highly Distinct Virulence Phenotypes Through Hamster Experimental Infection

“…The absence of profuse pulmonary lesions could result from the high infectious dose used in our experiments: the hamsters could have died before the infection invaded the lungs ( Diniz et al., 2011 ). As for the single surviving hamster, a recent study has shown that females are more resistant than males to L. interrogans infection ( Gomes et al., 2018 ). The obtained low survival rate might be actually zero if males had been used instead of females.…”

Leptospira and Leptospirosis

“…The environmental exposure is detailed in section 2. Of note, males are infected more frequently than females, possibly reflecting both an occupational nature of the transmission and sex-related susceptibility (Costa et al, 2014;Haake and Levett, 2015;Gomes et al, 2018). Global incidence rates are indicated in Table 1.…”

A Mouse Model of Sublethal Leptospirosis: Protocols for Infection with Leptospira Through Natural Transmission Routes, for Monitoring Clinical and Molecular Scores of Disease, and for Evaluation of the Host Immune Response

“…The age of the mice is known to affect the kinetics of disease progression (Nally et al., 2005; Richer et al., 2015). We found that male hamsters are more susceptible to lethal infection than their female counterparts (Gomes, Guedes, Potula, Dellagostin, & Gomes‐Solecki, 2018). Although we have not repeated these experiments using mice, it is reasonable to expect that male mice could be more susceptible to leptospirosis.…”