RESUMO
In sheep farms, oocyst shedding by asymptomatic adult carriers is one of the mechanisms which may explain maintenance of infections by Cryptosporidium parvum between lambing periods. The objective of this work was to investigate this hypothesis and the existence of a periparturient rise in oocyst shedding. Fourteen pregnant sheep were randomly selected from two farms with a history of neonatal diarrhoea caused by C. parvum and samples were collected from the 6th week before birth until 2 weeks after birth. Faecal samples were filtered, concentrated and examined for oocysts using an indirect immunofluorescence assay. The kinetics of anti-C. parvum antibodies (IgG and IgA) were studied using an indirect enzyme-linked immunosorbent assay. All except one animal excreted C. parrum oocysts at some time during the experimental period. The percentage of animals passing oocysts increased in the first week post-partum (farm 1) and in the first week before birth (farm 2). The numbers of oocysts excreted ranged from 20-440 oocysts g(-1) of faeces. In contrast, no significant changes in the anti-C. parvum immunoglobulin levels were observed over the sampling period. Finally, a high percentage of lambs (71%) born to these ewes acquired infection in the first 2 weeks of life.
Assuntos
Criptosporidiose/veterinária , Complicações Parasitárias na Gravidez/veterinária , Doenças dos Ovinos/transmissão , Animais , Animais Recém-Nascidos , Anticorpos Antiprotozoários/sangue , Criptosporidiose/parasitologia , Criptosporidiose/transmissão , Cryptosporidium parvum/isolamento & purificação , Fezes/parasitologia , Feminino , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Trabalho de Parto , Contagem de Ovos de Parasitas , Gravidez , Complicações Parasitárias na Gravidez/parasitologia , Ovinos , Doenças dos Ovinos/parasitologiaRESUMO
In a flock of cashmere goats sited in Asturias (NW, Spain) diminished efficacy was observed following treatment with netobimin and consequently a study to demonstrate the existence of anthelmintic resistance and the species of nematode involved was conducted. Results from faecal egg count reduction tests before and after treatment with netobimin or ivermectin showed efficacies of 89.4 (81.8-94.8) and 99.7% (93.9-99.9%), respectively. Teladorsagia circumcincta was found to be the dominant species involved in netobimin resistance. Effective dose (ED50) values in the egg hatch assay of 0.22 microgram thiabendazole ml-1 confirmed the existence of benzimidazole carbamate resistant nematodes. To the best of our knowledge, this is the first report on the existence of anthelmintic resistant nematodes from ruminants in Spain.