Study of the prevalence of Capillaria hepatica in humans and rodents in an urban area of the city of Porto Velho, Rondônia, Brazil.

INTRODUCTION: Hepatic capillariosis, caused by Capillaria hepatica (Calodium hepaticum) (Bancroft, 1893), Travassos, 1915 (Nematoda, Trichinelloidea, Capillariidae), is a common zoonosis in rodents but is rare in humans. Seventy-two cases in humans have been reported worldwide since the first case was described by MACARTHUR in 192417,27. This study aimed to determine the prevalence of Capillaria hepatica in humans and rodents in an urban area of Porto Velho, the capital of Rondônia, in Brazil. METHODS: After conducting a census of the area, 490 residents were randomly selected, and, after signing a term of consent, provided blood samples that were screened for anti-Capillaria hepatica antibodies. Simultaneously, rats were captured to assess the prevalence of this parasite in rodents by histopathological examination in liver sections. RESULTS: A prevalence of 1.8% was found among residents who had specific antibodies at a dilution of 1:150, indicating exposure to parasite eggs; 0.8% of the subjects also had positive titers at a dilution of 1:400, indicating true infection. The prevalence in rats was 2%. CONCLUSIONS: The prevalence of infection with this parasite among humans and rats was low. While the prevalence encountered among humans was within the limits reported in the literature, the prevalence among rodents was much lower.

Development of a reverse transcription quantitative real-time PCR-based system for rapid detection and quantitation of hepatitis delta virus in the western Amazon region of Brazil.

The hepatitis delta virus (HDV) is a pathogen that causes a severe and rapidly progressive disease of hepatocytes. The measurement of viral load in the peripheral blood of patients with HDV infections is important for diagnosis, treatment monitoring, and support for follow-up studies of viral replication during the course of the disease. This study reports the development of an assay capable of detecting and quantifying the abundance of HDV particles in serum samples, based on reverse-transcription quantitative PCR (RT-qPCR). Two standards for calibration were produced for determining the viral load of HDV: a cDNA cloned into a linear plasmid and a transcribed RNA. For validating this assay, 140 clinical samples of sera were used, comprising 100 samples from patients who tested positive for anti-HDV and hepatitis B virus surface antigen (HBsAg) by ELISA; 30 samples from blood donors; 5 samples monoinfected with hepatitis B virus (HBV); and 5 samples monoinfected with hepatitis C virus (HCV). The HDV RT-qPCR assay performed better when calibrated using the standard based on HDV cDNA cloned into a linear plasmid, yielding an efficiency of 99.8% and a specificity of 100% in the in vitro assays. This study represents the first HDV RT-qPCR assay developed with clinical samples from Brazil and offers great potential for new clinical efficacy studies of antiviral therapeutics for use in patients with hepatitis delta in the western Amazon region.

Study of the prevalence of capillaria hepatica in humans and rodents in an urban area of the city of Porto Velho, Rondônia, Brazil / Estudo da prevalência da Capillaria hepatica em humanos e roedores em área urbana da cidade de Porto Velho, Rondônia, Brasil

Introduction: Hepatic capillariosis, caused by Capillaria hepatica (Calodium hepaticum) (Bancroft, 1893), Travassos, 1915 (Nematoda, Trichinelloidea, Capillariidae), is a common zoonosis in rodents but is rare in humans. Seventy-two cases in humans have been reported worldwide since the first case was described by MACARTHUR in 192417,27. This study aimed to determine the prevalence of Capillaria hepatica in humans and rodents in an urban area of Porto Velho, the capital of Rondônia, in Brazil. Methods: After conducting a census of the area, 490 residents were randomly selected, and, after signing a term of consent, provided blood samples that were screened for anti-Capillaria hepatica antibodies. Simultaneously, rats were captured to assess the prevalence of this parasite in rodents by histopathological examination in liver sections. Results: A prevalence of 1.8% was found among residents who had specific antibodies at a dilution of 1:150, indicating exposure to parasite eggs; 0.8% of the subjects also had positive titers at a dilution of 1:400, indicating true infection. The prevalence in rats was 2%. Conclusions: The prevalence of infection with this parasite among humans and rats was low. While the prevalence encountered among humans was within the limits reported in the literature, the prevalence among rodents was much lower.

Introdução: Capilaríase hepática é causada pela Capillaria hepatica (syn. Calodium hepaticum) (Bancroft, 1893), Travassos, 1915 (Nematoda, Trichinelloidea, Capillariidae), sendo uma zoonose comum entre roedores, porém rara em humanos. Setenta e dois casos humanos foram relatados na literatura mundial desde o primeiro caso descrito por MACARTHUR em 192417,27. O objetivo desse estudo é determinar a prevalência da Capillaria hepatica em humanos e roedores de área urbana da cidade de Porto Velho, capital de Rondônia, Brasil. Método: Após realizar um censo da área, 490 moradores foram aleatoriamente selecionados e assinaram termo de consentimento, foram colhidas amostras de sangue para testar anticorpos anti-Capillaria hepatica. Simultaneamente, ratos foram capturados para determinação da prevalência deste parasita através do exame histopatológico em cortes de fígado. Resultados: Foi encontrada entre humanos prevalência de 1,8% de positividade para anticorpos específicos em diluição de 1:150, indicando exposição aos ovos do parasito; 0,8% desses também deram testes positivos quando seus soros sofreram diluição de 1:400, indicando infecção verdadeira. Nos ratos, a prevalência foi de 2%. Conclusão: A prevalência encontrada para o parasito entre homens e roedores foi baixa. Enquanto a prevalência encontrada entre humanos esteve dentro dos limites encontrados na literatura, a prevalência entre roedores foi bem menor.