Capillariaisis (Trichurida, Trichinellidae, <it>Capillaria hepatica</it>) in the Brazilian Amazon: low pathogenicity, low infectivity and a novel mode of transmission

• Main Authors: Vera Luana, de Souza Almeida Aranha Camargo Juliana, Camargo Luis, di Tarique Crispim Barreto Pedro, Tourinho Eudes, de Souza Marcia
• Format: Article
• Language: English
• Published: BMC 2010-02-01
• Series: Parasites & Vectors
• Online Access: http://www.parasitesandvectors.com/content/3/1/11

<p>Abstract</p> <p>Background</p> <p>Human capillariasis caused by <it>Capillaria hepatica (syn. Calodium hepaticum) </it>is a rare disease with no more than 40 cases registered around the world. Classically, the disease has severe symptoms that mimic acute hepatitis. Natural reservoirs of <it>C. hepatica </it>are urban rodents (<it>Mus musculus </it>and <it>Rattus novergicus</it>) that harbor their eggs in the liver. After examining the feces of 6 riverine inhabitants (Rio Preto area, 8° 03'S and 62° 53' W to 8° 14'S and 62° 52'W) of the State of Rondonia, Brazil, and identifying <it>C. hepatica </it>eggs in their feces, the authors decided to investigate the real dimension of these findings by looking for two positive signals.</p> <p>Methods</p> <p>Between June 1^stand 15^th, 2008, 246 out of 304 individuals were clinically examined. Blood samples were collected, kept under -20°C, and test by the indirect immunofluorescence technique.</p> <p>Results</p> <p>The first positive signal was the presence of specific antibodies at 1:150 dilution, which indicates that the person is likely to have been exposed to eggs, most likely non-infective eggs, passing through the food chain or via contaminated food (total prevalence of 34.1%). A second more specific signal was the presence of antibodies at higher titers, thus indicating true infection.</p> <p>Conclusions</p> <p>The authors concluded that only two subjects were really infected (prevalence of 0.81%); the rest was false-positives that were sensitized after consuming non-embryonated eggs. The present study is the first one carried out in a native Amazonian population and indicates the presence of antibodies against <it>C. hepatica </it>in this population. The results further suggest that the transmission of the parasite occurs by the ingestion of embryonated eggs from human feces and/or carcasses of wild animals. The authors propose a novel mode of transmission, describing the disease as a low pathogenic one, and showing low infectivity.</p>