Cinética da infecção por Fasciola hepatica em Lymnaea (=Pseudosuccinea) columella proveniente do municipio de Confins - Minas Gerais

• Ano de defesa: 2006
• Autor(a) principal: Vinicius Marques Antunes Ribeiro
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Fasciola; Lymnaea columella; Hemocitos; hepatica; Desenvolvimento intramolusco; Sazonalidade; Parasitologia; Farmacologia
• Link de acesso: http://hdl.handle.net/1843/BUBD-A92NHH

The importance of Lymnaea columella stands out in Fasciola hepaticaepidemiology due to growing number of natural infection reports of this mollusc by the trematode in Brazil and several countries. The present work assessed the seasonality of molluscs collected from January 2013 to December 2014 in the border of natural watering troughs of cattle in oxbow lake situated in Confins municipality (19°40'17.26" S, 43°57'52.57" O), Minas Gerais (MG) state, Brazil. The molluscs were collected in aquatic vegetation, tree trunks and mud bottom and in natural watering troughs. In laboratory molluscs and vegetation were identified. The climatic factors of average monthly temperature and rainfall influenced the population of molluscs. L. columella, Biomphalaria spp., Melanoides spp., Physa spp. and Pomacea spp.. From a total of 1909 collectedgastropods, Physa spp. was more abundant (n=537), followed by Melanoides, spp. (n=487), Pomacea spp. (n=407), L. columella (n=351) and Biomphalaria spp. (n=127). The number of L. columella collected in 2014 (n=267) was greater than that by the year 2013 (n= 84), when the total annual rainfall was 1.7 times higher. During the study, Biomphalaria spp. and Melanoides spp. presented fewer specimens collected in the dry season, while Physa spp., occurred throughout the whole study period, with variable monthly distribution between the dry and rainy seasons in the two years of collecting. Pomacea spp., obtained the highest number of months during the rainy season of 2013 and 2014. There were not developmental stages of F. hepatica in specimens of L.columella collected. The dynamic of F. hepatica infection in L. columella was also assessed by histology and circulating mollusc haemocytes counts. Miracidia were observed in head-foot and mantle tissues at 30 minutes postinfection. Miracidia/sporocysts in the mantle tissues 1° dpi, and fully formed sporocysts were observed in the head-foot at 7° dpi. Rediae became evident between 10° dpi and 14° dpi located between the head-foot and haemocoel. Between 45° e 50° dpi, the rediae in the digestive gland contained cercariae. The statistical analysis of the total haemocytes of L. columella infected by F. hepatica showed significant differences on the 30 minutes post-infection (p<0.05) and 1° dpi (p<0.05), 14° dpi (p<0.001), 21° dpi (p<0.05), 28° dpi (p<0.01) and 45° dpi (p<0.001) in comparison to uninfected molluscs (0 dpi). Therefore, the interference observed on the internal defence system of L. columella may have direct association with the development of F. hepatica.