BALB/c mice resistant to Toxoplasma gondii infection proved to be highly susceptible when previously infected with Myocoptes musculinus fur mites

Abstract

The immune response induced by Toxoplasma gondii is characterized by Th1 immune mechanisms. We previously demonstrated that C57BL/6 mice infested with Myocoptes musculinus and infected with T. gondii by intraperitoneal route undergo accelerated mortality according to Th2 immune mechanisms induced by the acarian. To evaluate whether infection with M. musculinus influences T. gondii-induced Th1 response in a resistant mouse lineage, BALB/c, which develops latent chronic toxoplasmosis in a way similar to that observed in immunocompetent humans, this study was done. The animals were infected with T. gondii ME-49 strain 1 month after M. musculinus infestation, being the survival and the immune response monitored. The double-infected displayed higher mortality rate if compared with the mono-infected mice. In addition, infection with M. musculinus changed the T. gondii-specific immune response, converting BALB/c host to a susceptible phenotype. Spleen cells had increased the levels of IL-4 in double-infected mice. This alteration was associated with severe pneumonia, encephalitis and wasting condition. In addition, a higher tissue parasitism was observed in double-infected animals. It can be concluded that infection with these two contrasting parasites, M. musculinus and T. gondii, may convert an immunocompetent host into a susceptible one, and such a host will develop severe toxoplasmosis.

Immunopathology in ocular toxoplasmosis: facts and clues

“…The up-regulation of IL-4 in a Toxoplasmainfected host indicates the host is susceptible to the parasite, even if it is previously deemed to be resistant to the organism (Welter et al 2007). …”

Neurological and behavioral abnormalities, ventricular dilatation, altered cellular functions, inflammation, and neuronal injury in brains of mice due to common, persistent, parasitic infection

“…T. gondii infection modulates both immune responses and outcomes of many concomitant infections and tumors. The outcome of T. gondii infection has been reported to be modulated substantially by presence of either prior infections or concomitant infections [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. Earlier studies have attributed a variety of different findings to T. gondii infection (e.g.…”

Efficacy and safety of topical eprinomectin to controlMyocoptes musculinus infestation in mice

“…Infested mice may also be prone to secondary infections, reduced life span, and decrease of body weight (WELTER et al, 2007).…”

“…Fur mites infestations in research colonies remain a constant management challenge. Fur mites have been reported to interfere with established research models by directly potentiating allergictype hypersensitivity reactions (MORITA et al, 1999), indirectly interfering with normal immune responses to other (WELTER et al, 2007) and have been shown to provoke a Th2 immune response and elevate serum IgE (LALTOO et al, 1979;JUNGMANN et al, 1996).…”