Description of an outbreak of human trichinellosis in an area of Argentina historically regarded as Trichinella-free: The importance of surveillance studies

Abstract

Trichinellosis is an important food-borne zoonosis which is not treated as a major publichealth concern in Argentina. After more than 20 years without reports of infection in an arearegarded as Trichinella-free, research studies reported that infection occurred in humans,pigs and game animals, including the recent outbreak of human trichinellosis revealed here.The outbreak, affecting 64 individuals, occurred in July 2010 in the province of Entre Ríos. Epidemiological studies, clinical observations, laboratory analyses and immunoserologicalspecific assays (indirect immunofluorescence, IIF, and ELISA) were performed. Food sampleswere analyzed by artificial digestion, and Trichinella larvae isolates were identified to thespecies level by multiplex PCR.The main source of infection, commercially available food, had a parasite load of1.1 muscle larvae per gram. Larvae were identified as Trichinella spiralis. Patients pre-sented predominantly with oedema, fever and myalgia; and laboratory findings and/orimmunoserological tests were positive for trichinellosis. Individuals received outpatienttreatment. No deaths or secondary sequelae were recorded.Results suggest that the presence of T. spiralis infection should be suspected in all endemicareas, especially where animal husbandry and official food safety controls are not properlyconducted. The lack of the cases reported ought not to be taken as a proof of parasiteabsence. We highlight the importance of the urgent need to implement interdisciplinaryand inter-institutional programs aimed to control infection transmission, to guarantee foodsafety and to conduct epidemiological surveillance studies.