Larval recovery of Toxocara cati in experimentally infected Rattus norvegicus and analysis of the rat as potential reservoir for this ascarid

Toxocara cati is a common feline parasite transmitted by the ingestion of embryonated eggs, by the transmammary route or by predation of paratenic hosts harbouring third-stage larvae in their bodies. In the present study, the larval distribution of T. cati in tissues and organs of Rattus norvegicus experimentally infected with 300 embryonated eggs was analysed. Third-stage larvae were recovered from livers, lungs, kidneys, eyes, brains and carcasses of infected rats, following tissue digestion with HCl 0.5 percent for 24 h at 37°C. Some differences from the known larval distribution of Toxocara canisin the same rodent species were found.

Survival of Trypanosoma cruzi in sugar cane used to prepare juice / Avaliação da sobrevida de Trypanosoma cruzi em cana de açúcar utilizada no preparo do caldo

Chagas disease can be transmitted to man by many different means, including contact with infected triatomine feces, blood transfusion, laboratory accidents, organ transplants, and congenital or oral routes. The latter mode has received considerable attention recently. In this assay, we evaluate the survival of Trypanosoma cruzi contaminating sugar cane used to prepare juice, as well as the viability and capacity for infection by the parasite after recovery. Thirty triatomines were contaminated with T. cruzi Y strain and 45 days later pieces of sugar cane were contaminated with the intestinal contents of the insects. The pieces were ground at different intervals after contamination (time = 0, 1, 4, 6, 12 and 24 hours) and the juice extracted and analyzed. Different methods were used to show T. cruzi in the juice: direct analysis, hematocrit tube centrifugation and QBC, and experimental inoculation in 47 female BALB/c mice (five control mice and seven mice for each interval examined (five inoculated orally and two intraperitoneally). Positive results were found using the direct analysis and QBC methods for juice prepared up to 12 hours after initial contamination. However, by the centrifugation technique, positivity was found only up to four hours after contamination of the sugar cane. Inoculated animals showed parasitemia during a 14 day observation period, demonstrating the high survival rate of T. cruzi in sugar cane.

A doença de Chagas pode ser transmitida ao homem através de vários mecanismos: fezes de triatomíneo infectado; transfusão sangüínea; acidente em laboratório; transplante de órgão; vias congênita ou oral convindo salientar que esta última tem motivado ocorrências recentemente. Neste estudo procuramos avaliar a sobrevida de Trypanosoma cruzi presente em cana de açúcar contaminada com o parasita, utilizada no preparo do caldo e, também, a viabilidade e a capacidade de infecção do parasita depois de ser recuperado. Trinta triatomíneos foram contaminados com a cepa Y de T. cruzi; após 45 dias realizamos a contaminação de pedaços de cana de açúcar com o conteúdo intestinal dos insetos. Estes pedaços foram moídos em diferentes tempos: no início (tempo 0) e após 1, 4, 6, 12 e 24 horas da contaminação e o caldo extraído foi analisado por diferentes métodos: direto, centrifugação em tubo de hematócrito, QBC. Este caldo contaminado foi inoculado em 47 camundongos machos BALB/c, sendo cinco controles (com caldo de cana limpo) e sete para cada tempo estudado (cinco inoculados pela via oral e dois pela intraperitoneal). Na análise direta e no QBC obtivemos resultados positivos até 12 horas e, na centrifugação, ocorreu positividade somente até as quatro horas. As parasitemias dos animais inoculados foram todas positivas em um período de 14 dias de observação, demonstrando alto grau de sobrevivência do T. cruzi na cana de açúcar.