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- Title
Calodium hepaticum: Household Clustering Transmission and the Finding of a Source of Human Spurious Infection in a Community of the Amazon Region.
- Authors
Gonçalves, Alessandra Queiroga; Ascaso, Carlos; Santos, Ivanildes; Serra, Paula Taquita; Julião, Genimar Rebouças; Orlandi, Patricia Puccinelli
- Abstract
Background: Calodium hepaticum (syn. Capillaria hepatica) is a worldwide helminth parasite of which several aspects of transmission still remain unclear. In the Amazon region, the mechanism of transmission based on the ingestion of eggs present in the liver of wild mammals has been suggested as the cause of the spurious infections described. We performed an epidemiological investigation to determine the incidence, risk of spurious infection and the dynamics of transmission of C. hepaticum in a community of the Brazilian Amazon. Methodology/Principal Findings: Stool samples of 135 individuals, two dog feces and liver tissue from a peccary (captured and eaten by the residents) were analyzed by conventional microscopy. Dog feces were collected from the gardens of households presenting human cases of spurious C. hepaticum infections. Community practices and feeding habits related to the transmission of the parasite were investigated. The individual incidence of spurious infection was 6.7% (95% CI: 2.08–11.24). Cases of spurious infection were observed in 7.5% of the families and the household incidence was from 50% to 83.3%. The risk of spurious infection was 10-fold greater in persons consuming the liver of wild mammals (p = 0.02). The liver tissue of a peccary and one feces sample of a dog presented eggs of C. hepaticum. The consumption of the infected liver was the cause of the spurious infections reported in one household. Conclusions/Significance: This is the first identification of a source of spurious infection by C. hepaticum in humans and we describe a high rate of incidence in household clusters related to game liver alimentary habits. The finding of a dog feces contaminating peridomiciliary ground suggests the risk of new infections. We conclude that the mechanism of transmission based on the ingestion of liver is important for the dynamics of transmission of C. hepaticum in the studied area. Author Summary: The zoonotic parasite Calodium hepaticum is the causative agent of rarely reported liver disease (hepatic calodiasis) and spurious infections in humans. In spurious infections eggs of this parasite are excreted in the stools without causing disease. It has been suggested that the cause of this type of infection in Amazonian areas is the ingestion of liver of wild mammals infected with the eggs of the parasite. Nonetheless, studies are needed to confirm this mechanism of transmission and investigate its epidemiological importance. In the present study we report the high individual (6.7%) and household incidence (50%–83.3%) of spurious infection in a rural community of the Brazilian Amazon. We found a high risk of spurious infection among subjects who usually ate the liver of wild mammals and detected a source of spurious infection in humans (peccary liver) as well as, for the first time, ground contamination with infected dog feces in a household presenting human cases. We confirm the existence of this mechanism of transmission of C. hepaticum and suggest that it is important for transmission not only in this area but probably also in other areas of the Amazon with similar sociocultural characteristics.
- Subjects
Q fever; HOUSEHOLDS; INFECTIOUS disease transmission; INFECTION; LIVER diseases; FECES
- Publication
PLoS Neglected Tropical Diseases, 2012, Vol 6, Issue 12, p1
- ISSN
1935-2727
- Publication type
Article
- DOI
10.1371/journal.pntd.0001943