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Contribuição para a determinação de infeção por Cryptosporidium spp. em vitelos de explorações de carne das sub-regiões do Alentejo Central e Litoral
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Resumo(s)
A criptosporidiose é uma zoonose difundida por todo o mundo e é provocada por protozoários
pertencentes ao género Cryptosporidium que têm a capacidade de infetar mamíferos, aves,
répteis, anfíbios e peixes. A via de transmissão do parasita é fecal-oral podendo ocorrer de
forma direta através do contacto com fezes provenientes de animais portadores ou de forma
indireta através do contacto com superfícies, águas ou alimentos contaminados com oocistos
esporulados. Os vitelos infetam-se nos primeiros dias de vida, sendo estes os principais
responsáveis pela perpetuação da doença nas explorações.
Este estudo teve como principal objetivo a avaliação da percentagem de infeção de
Cryptosporidium spp. em vitelos pertencentes a explorações de carne do Alentejo Central e
Litoral. As amostras foram obtidas por conveniência a partir de 105 vitelos com idades
compreendidas entre os 10 e os 30 dias de vida e pertencentes a 22 explorações sediadas
nas referidas sub-regiões. Os resultados foram obtidos através de observação ao microscópio
das amostras após realizados os esfregaços fecais e respetivas colorações com a técnica de
Ziehl-Neelsen modificada.
A percentagem global de infeção por Cryptosporidium spp. ficou definida em 25,7% dos
animais examinados e 63,6% das explorações alvo de estudo apresentaram pelo menos um
animal positivo à observação microscópica das amostras.
Os dados obtidos demonstraram uma forte relação entre a consistência das fezes e a
presença de Cryptosporidium spp., sendo que 48,5% dos animais com fezes diarreicas na
altura na colheita das amostras apresentaram-se infetados pelo parasita.
Embora o lactato de halofuginona esteja descrito como tratamento efetivo para o
Cryptosporidium spp., a execução do seu protocolo em explorações em regime extensivo não
é fácil e as melhores alternativas passam pela adoção de boas práticas de maneio, tratamento
das águas de bebida dos animais e vacinação do efetivo contra outros agentes patogénicos
causadores de diarreias neonatais.
ABSTRACT - CONTRIBUTION TO THE DETERMINATION OF Cryptosporidium spp. INFECTION IN CALVES OF BEEF FARMS FROM CENTRAL AND COASTAL ALENTEJO SUBREGIONS - Cryptosporidiosis is a widespread zoonosis caused by protozoa of the genus Cryptosporidium. They are parasites that have the ability to infect mammals, birds, reptiles, amphibians and fish. The parasite transmission pathway is fecal-oral and may occur directly through contact with feces from animal carriers or indirectly through contact with surfaces, waters or food contaminated with sporulated oocysts. Calves become infected in their first days of life, and these are the main responsible for the perpetuation of the disease on the farms. The main objective of this study was to evaluate the percentage of Cryptosporidium spp. infection in calves belonging to beef cattle farms in the Central and Coastal Alentejo. Convenience sampling was obtained from 105 calves aged between 10 and 30 days old and belonging to 22 farms based in these sub-regions. The results were obtained by microscopic observation of the samples after being colored with modified Ziehl-Neelsen technique. The overall percentage of Cryptosporidium spp. infection was defined in 25.7% and 63.6% of the study target farms presented at least one positive animal to the microscopic observation of the samples. The obtained data showed a strong relationship between feces consistency and the presence of Cryptosporidium spp. A percentage of 48.5% of the animals with diarrheal feces at the time of sampling were infected by the parasite. Although halofuginone lactate is described as an effective treatment for Cryptosporidium spp. the protocol in beef farms is not easy to apply and the best alternatives are the adoption of good animal husbandry practices, treatment of animal drinking water and vaccination of herds against pathogens which cause neonatal diarrhea.
ABSTRACT - CONTRIBUTION TO THE DETERMINATION OF Cryptosporidium spp. INFECTION IN CALVES OF BEEF FARMS FROM CENTRAL AND COASTAL ALENTEJO SUBREGIONS - Cryptosporidiosis is a widespread zoonosis caused by protozoa of the genus Cryptosporidium. They are parasites that have the ability to infect mammals, birds, reptiles, amphibians and fish. The parasite transmission pathway is fecal-oral and may occur directly through contact with feces from animal carriers or indirectly through contact with surfaces, waters or food contaminated with sporulated oocysts. Calves become infected in their first days of life, and these are the main responsible for the perpetuation of the disease on the farms. The main objective of this study was to evaluate the percentage of Cryptosporidium spp. infection in calves belonging to beef cattle farms in the Central and Coastal Alentejo. Convenience sampling was obtained from 105 calves aged between 10 and 30 days old and belonging to 22 farms based in these sub-regions. The results were obtained by microscopic observation of the samples after being colored with modified Ziehl-Neelsen technique. The overall percentage of Cryptosporidium spp. infection was defined in 25.7% and 63.6% of the study target farms presented at least one positive animal to the microscopic observation of the samples. The obtained data showed a strong relationship between feces consistency and the presence of Cryptosporidium spp. A percentage of 48.5% of the animals with diarrheal feces at the time of sampling were infected by the parasite. Although halofuginone lactate is described as an effective treatment for Cryptosporidium spp. the protocol in beef farms is not easy to apply and the best alternatives are the adoption of good animal husbandry practices, treatment of animal drinking water and vaccination of herds against pathogens which cause neonatal diarrhea.
Descrição
Dissertação de Mestrado Integrado em Medicina Veterinária
Palavras-chave
bovinos de carne vitelos Cryptosporidium spp. percentagem de infeção Alentejo Central e Litoral Portugal beef cattle calves Cryptosporidium spp. infection percentage Central and Coastal Alentejo
Contexto Educativo
Citação
Saramago JMG 2019. Contribuição para a determinação de infeção por Cryptosporidium spp. em vitelos de explorações de carne das sub-regiões do Alentejo Central e Litoral. [dissertação de mestrado]. Lisboa: FMV-Universidade de Lisboa.
Editora
Universidade de Lisboa, Faculdade de Medicina Veterinária