ABSTRACT
Abstract The lymnaeids are important in the epidemiology of Fasciola hepatica, a neglected and endemic zoonosis. The interaction between the internal defense system of Pseudosuccinea columella and F. hepatica has been little studied. In the present study the effect of infection by F. hepatica on P. columella circulating haemocytes was investigated. Changes in the average number of total circulating haemocytes have been observed at 30 minutes post-infection and 1, 7, 10, 14, 21, 28 and 50 days post-infection (dpi). Miracidia were observed head-foot and mantle at 30 minutes post-infection. Miracidia/Sporocysts in the mantle skirt 1 dpi, and fully formed sporocysts were observed in the head-foot at 7 dpi. Rediae became evident at 10 dpi and were located between the haemocoel and the muscles from 14 dpi; 50 dpi, the rediae in the digestive gland contained cercariae. The statistical analysis of the total haemocytes of P. columella infected by F. hepatica showed significant differences on the 30 minutes post-infection and 1, 14, 21, and 28 dpi in comparison to uninfected molluscs (0 dpi). Therefore, the interference observed on the internal defence system of P. columella may have direct association with the development of F. hepatica.
Resumo Os limnaeideos são importantes na epidemiologia de Fasciola hepatica, uma zoonose negligenciada e endêmica. A interação entre o sistema interno de defesa de Pseudosuccinea columella e F. hepatica tem sido pouco estudada. No presente estudo, investigou-se o efeito da infecção por F. hepatica nos hemócitos circulantes de P. columella. Alterações no número médio de hemócitos circulantes foram observadas aos 30 minutos e 1, 7, 10, 14, 21, 28 e 50 dias após a infecção (dpi). Miracídios foram observados na região cefalopodal e manto aos 30 minutos após a infecção. Miracídio/esporocistos foram observados no colar do manto ao 1 dpi, e esporocistos totalmente formados na região cefalopodal aos 7 dpi. Rédias tornam-se evidentes aos 10 dpi entre a hemocele e músculos a partir de 14 dpi; e rédias com cercárias próximas a glândula digestiva aos 50 dpi. A análise estatística dos hemócitos totais de P. columella infectados por F. hepatica demonstrou diferenças significativas nos 30 minutos pós-infecção e 1, 14, 21 e 28 dpi em comparação aos moluscos não infectados (0 dpi). Portanto, a interferência observada no sistema de defesa interna de P. columella pode ter associação direta com o desenvolvimento de F. hepatica.
Subject(s)
Animals , Snails/parasitology , Fascioliasis/veterinary , Hemocytes/parasitology , Fascioliasis/bloodABSTRACT
Mollusks are intermediate hosts of Angiostrongylus vasorum, which is a parasite with zoonotic potential for which canids are the definitive host. In this study, 180 specimens of Achatina fulica that had been experimentally infected with 1,000 L1 of A. vasorum were finely chopped to evaluate four tissue digestion techniques: 1% potassium hydroxide (group I); 3% hydrochloric acid (group II); 1% hydrochloric acid and pepsin (group III) with procedures at 37 ºC in a double boiler; and Baermann at 42 °C (group IV). On the first, eighth and thirtieth days after infection, L1, L2 and L3 were obtained, and 240 L3 recovered from group III were offered to a dog. The results were the following: group I: 59% L1, 7% L2, 13% L3; group II: 31% L1, 13% L2, 27% L3; group III: 23% L1, 22% L2, 30% L3; and group IV: 0.3% L1, 0.02% L2, 5% L3. Live larvae wereobserved in group III: 15.5% L1, 8.22% L3; group II: 9.8% L3; and group IV: 100% L1, L2 and L3. Larvae were detected 56 days after the dog became infected. All larvae stages of A. vasorum were recovered and identified through the techniques evaluated, thus confirming the potential of A. fulica as an intermediate host of the nematode