Trichinellosis is an infectious disease caused by Trichinella spp. that affects humans and many other mammals. While some European countries, such as Denmark and The Netherlands, are considered free of infection with Trichinella, Spain is one of two areas that is endemic for domestic trichinellosis. However, despite regulations in Spain to control this disease, it remains a major public health threat.
Until recently, most human infections with Trichinella were attributed to Trichinella spiralis. However, a more precise characterization has shown an association of other species of Trichinella such as T. pseudospiralis, T. nativa, and T. britovi with such infections.1–5 Two human infections with T. britovi have been previously described.6,7
In this report, we present the epidemiologic and serologic data from cases of trichinellosis caused by T. britovi in an outbreak that occurred in April–May 2000 in Granada, Spain, and extended into Almeria and Malaga, others provinces in the Andalusian region. This study was reviewed and approved by Uunidad de Nutrición Animal, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, and Hospital Universitario de San Cecilio, Granada.
The probable source of infection was sausage made from a mixture of inspected pork and uninspected wild boar meat. Parasite infection was detected by acid-pepsin digestion of the sausage. The parasite involved was identified as T. britovi by Western blotting of a crude extract with specific monoclonal antibodies at the Carlos III Health Institute (Madrid, Spain). Thirty-eight people (16 males and 22 female) were affected and 15 were hospitalized at the University Hospital of San Cecilio, Granada. All people who reported eating the suspected products had some signs and/or symptoms related to trichinellosis. The time between ingestion of infected meat and the appearance of clinical signs ranged from 15 to 30 days. All patients were treated with albendazole at a dose of 600 mg for 10 days. Of the 38 people infected, 92.0% had myalgias, 47.6% had diarrhea and/or vomited, 78.6% had periorbital edema, and 76.0% had fever. Eosinophil levels were less than 5% of the total leukocyte counts in 85.7% of the patients. Muscle enzyme levels were elevated in 33 patients. Levels of creatinine phosphokinase (range = 200–2,213 U/L) were elevated in 85.7% and levels of lactate dehydrogenase (range = 560–7,558 U/L) were elevated in 78.67%. Twenty-two of the 38 patients (15 hospitalized and 7 nonhospitalized) were serologically studied. An IgG indirect imunofluorescence (IIF) test with whole larvae and an IgG Western blot with crude extract were performed to detect antibodies to cuticular and somatic antigens, respectively. Of the 22 patients, 16 (72.7%) were positive by the IIF test with titers ranging from 1:20 to 1:10,240 (most common titer = 1:2,560). Twenty patients (90.9%) were positive by Western blot.
As in other outbreaks of trichinellosis, two different responses were observed. The first was in patients with low IgG IIF titers (1:80–1:160). This response was directed mainly to TSL-1 antigens, but high molecular weight antigens were also recognized. The other response was observed in patients with higher IgG IIF titers. In this response, in addition to the antigens indicated, polypeptides with apparent molecular masses less than 31 kD were observed.
In Spain, pork and wild boar are the main source of trichinellosis. Although it is a notifiable disease, it remains a major public health problem because the parasite is enzootic in domestic and wild animals. Andalusia, the region in which Granada is located, is a region that is endemic for this disease. It is worth noting that from 1984 to 2000, 19 outbreaks of trichinellosis were reported in Andalusia.8 The actual incidence is probably greater because asymptomatic cases are abundant. Our clinical findings did not differ from those reported by others.4,6 Eosinophil counts and muscle enzyme levels were higher than those found in other infections with T. britovi.4,5 In addition, Western blotting has been shown to be more effective than the IIF test in the diagnosis of trichinellosis.
Authors’ addresses: V. Gómez-García and M. Rodríguez-Osorio, Departamento de Nutrición Animal, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Professor Albareda 1, Granada 18008, Spain, Telephone: 34- 58-572-757, Fax: 34-58-572-753, E-mail:
Financial support: This work was supported by the grant AGR171 from the Junta de Andalucia.
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