EXTERNAL CHALLENGES AND CO-INFECTION WITH TRY. CRUZI ENHANCES TOLERANCE WHILE DIMINISHED RESISTANCE AGAINST TRI. SPIRALIS ON LABORATORY RATS

PALAVECINO CINTIA CAROLINA; FANTOZZI MARÍA CECILIA; CUERVO PABLO FERNANDO; RACCA ANDREA LAURA

Congreso; 15th International Congress of Parasitology; 2022

Introduction: There are two intrinsically different defence strategies that the host implements in order to face parasite infection. A host may resist infection by fighting the intruder or it may tolerate its presence by minimizing the damage on health condition. The aim was to evaluate the effect of different scenarios of external challenges (food restriction, social conflict and co-infection with Trypansoma cruzi) on defence strategy against the nematode Trichinella spiralis on laboratory rats.Methods: We used a total of 32 adult male rats (Rattus norvegicus, WISTAR/Cmedc) in each of two experiments that lasted for ten weeks. The experiments were defined by the combination of parasites: Tri. spiralis alone or co-infecting with Try. cruzi. After four weeks of exposure to food restriction (FR), social conflict (SC), both (FR+SC) or control (C), rats were inoculated with parasites. Tolerance was quantified as the slope of the regression between body weight change and Tri. spiralis intensity. Resistance was quantified as total Tri spiralis intensity.Results: FR rats were less tolerant in mono- infection compared to co-infection. On the other hand, resistance was higher in SC rats, but only in absence of Try. cruzi.Conclusions: FR had a negative effect on health condition, which influenced its capacity to tolerate nematodes as parasite intensity enhanced. However, the effect of Tri. spiralis intensity on host health was attenuated in co-infection. Moreover, Try. cruzi presence reduced resistance in SC rats, while enhanced tolerance in FR rats. Taken together, these results may indicate a shift on defence strategies in rats exposed to nematodes depending on the type of external challenge and on concomitant infections.