Instituto Leônidas e Maria Deane-Fiocruz Amazônia, Manaus, Amazonas, Brazil.
PLoS Negl Trop Dis. 2012;6(12):e1943. doi: 10.1371/journal.pntd.0001943. Epub 2012 Dec 20.
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.
Calodium hepaticum（又名Capillaria hepatica）是一种世界性的寄生虫，其传播机制的多个方面仍不清楚。在亚马逊地区，基于摄入存在于野生动物肝脏中的虫卵的传播机制已被提出是导致该地区描述的虚假感染的原因。我们进行了一项流行病学调查，以确定巴西亚马逊地区一个社区中 Calodium hepaticum 的发病率、虚假感染的风险和传播动态。
方法/主要发现：对 135 个人的粪便样本、两只狗的粪便和一头野猪的肝脏组织（由居民捕获并食用）进行了常规显微镜检查。从有人类虚假感染 Calodium hepaticum 病例的家庭的花园中收集狗的粪便。调查了与寄生虫传播有关的社区做法和喂养习惯。虚假感染的个体发病率为 6.7%（95%置信区间：2.08-11.24）。在 7.5%的家庭中观察到虚假感染病例，家庭发病率为 50%-83.3%。食用野生动物肝脏的人感染虚假感染的风险增加了 10 倍（p=0.02）。一头野猪的肝脏组织和一只狗的粪便样本中都发现了 Calodium hepaticum 的虫卵。一户人家报告的虚假感染是由食用受感染的肝脏引起的。
结论/意义：这是首次在人类中发现 Calodium hepaticum 引起的虚假感染源，我们描述了与食用野味肝脏有关的家庭聚集的高发病率。狗粪便污染周围环境的发现提示存在新的感染风险。我们的结论是，基于摄入肝脏的传播机制对于研究区域中 Calodium hepaticum 的传播动态非常重要。
