Evaluation of the infectivity and the persistence of Trichinella patagoniensis in a new host, the guinea pig

FARIÑA, F.; PASQUALETTI, M.; ERCOLE, M.; CARDILLO, N; ROSA, A.; KRIVOKAPICH, S.; RIBICICH, M

Conferencia; 14th International Conference on Trichinellosis; 2015

Trichinella patagoniensis is a new species of the genus Trichinella that is widespread in Argentina, with the cougar (Puma concolor) serving as a natural reservoir. Transmission of parasites of the genus Trichinella depends, among other factors, on the ability of muscle larvae to remain infective in muscle tissue under environmental conditions. The aim of the present work was to study the infectivity and capability of T. patagoniensis muscle larvae to survive in decomposed muscle tissue of guinea pigs. Sixteen Ssi:AL guinea?pig?female were orally inoculated with 2000 muscle larvae (ML) of T. patagoniensis (ISS2311). After 42 days of infection, all animals were euthanized. Animals were eviscerated and corpses were placed on the surface of soil that was inside plastic boxes. Boxes were subjected to the effects of weather conditions of the summer 2014?2015 in Buenos Aires, Argentina. At day 0, previous to the placing of the corpses, two infected animals were subjected to artificial digestion. Weekly, corpses were analysed by the same technique. In order to assess the infectivity of the ML recovered, 300 ML were orally inoculated to three female Balb/C mice. After 42 days, mice were euthanized and the carcasses were digested. Trichinella ML were counted employing a stereomicroscope. The present study was approved under permit number 2014/01 by the Institutional Committee for Use and Care of Laboratory animals of the Faculty of Veterinary Sciences. Guinea pigs became infected with T. patagoniensis, ML were recovered from decaying muscle up to the third week of exposure to environmental conditions. ML became infective to Balb/C mice until the second week. The RCI value in mice was reduced from 36.18 ± 3.44 to 15.3 ± 4.03 from week 0 to the second week. The maximum temperature recorded was 32 º C, the minimum temperature was 14.5 ºC with an average temperature of 26 º C and an average humidity of 67 %. Rainfalls were very frequent. The present results show for the first time that T. patagoniensis is able to complete its life cycle in guinea pigs, and thus, they could act as potential hosts of the parasite. T. patagoniensis would be able to survive and remain infective in rotten muscle for 2 weeks under the weather conditions of a hot summer, which would contribute to the maintenance of the sylvatic cycle of this parasite in the environment.