A review on Trichinella infection in South America

Abstract

Trichinella spp. causes human trichinellosis by means of the consumption of raw or inadequately treated meat from domestic or game animals. In the Americas, as well as in other continents, Trichinella infection is a health issue for humans and has a negative impact on the pork meat market, generated by people's fear of becoming infected with the parasite. The distribution of human cases and the sources of this disease in humans and animals were analysed in this report, which summarizes the information available regarding Trichinella infection in animals and humans in South America. Within South America, human infection with Trichinella was documented in Argentina and Chile during the period 2005-2019. Trichinellosis is endemic in these countries for, with human cases and foci in domestic and wild animals. In Argentina, human cases occur throughout the country, with foci found in pigs and wild animals. In Argentina, during the period 2012-2018, the number of suspected human cases reached 6,662. T. spiralis was identified in one South American sea lion (Otaria flavescens) from Patagonia, Argentina, for the first time in the region in 2018. In Chile, 258 human cases of trichinellosis were confirmed during the period 2005-2015; out of those 258 cases, most samples which tested positive for Trichinella spp. (29.5%) were detected in the Metropolitan district (Santiago de Chile and outskirts), and 17.4% in The Lake district. Regarding age brackets, people between 30-49 years of age showed the most cases (40.1%). In Brazil, the infection is absent in domestic species but it has been found in wild boars (Sus scrofa) but limited to one or more region of the country. Within the animal species destined for food in South America, those that showed higher parasitical loads were pigs and wild boars, while armadillos (Chaetophractus villosus) and peccaries (Tayassu tajacu) showed very low Trichinella spp. larvae loads (0.04 - 0.1 larvae/g). Antibodies against Trichinella spp. have been detected in pigs from Ecuador and Bolivia. In Bolivia, antibodies were also found in humans. Peru, Colombia and Uruguay have no documented presence of Trichinella spp. in animals and humans. There is insufficient information regarding the presence of Trichinella spp. in domestic and wild animals, as well as in humans, since only a very limited number of surveys have been carried out. No papers with information on Trichinella spp. circulating in animals or humans have been published regarding the situation in Guyana, Surinam, French Guiana, Venezuela and Paraguay. Considering the growth of the guinea pig meat market in the Andean region, and the high prevalence of the disease reported in free range pigs and wild boars, as well as other game animal species, it is important to focus on the role of biosecurity and risk management, while improving meat market regulations, and detection of infection prior to consumption, in order to reduce the risk of transmission of this zoonotic disease to humans.