Viabilidade do parasitismo por Haemonchus contortus em bovinos experimentalmente infectados
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Data
2014-08-01
Autores
Fávero, Flávia Carolina [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O sistema de criação conjunta ovinos/bovinos, visando melhor aproveitamento da pastagem, provendo diversificação lucrativa, pode deparar com problemas graves nas propriedades rurais, tais como as parasitoses. Dentre as mais importantes, destaca-se a hemoncose. As espécies Haemonchus placei e Haemonchus contortus são comumente encontradas parasitando bovinos e ovinos, respectivamente. A infecção de bovinos por H. contortus constitui, ainda, uma incógnita na literatura, sobretudo a brasileira. Este helminto tem sido descrito parasitando principalmente ovinos e caprinos. As espécies mais citadas parasitando bovinos são H. placei e H. similis. Portanto, objetivou-se no presente estudo avaliar a infectividade de H. contortus para bovinos e comparar sua patogenicidade à de H. placei. Para tal, foram utilizados 10 bezerros, criados e mantidos sem contato com helmintos, assim distribuídos: GI - dois bezerros não inoculados (controle), GII – quatro bezerros inoculados com larvas infectantes (L3) de H. contortus e GIII – quatro bezerros infectados com larvas (L3) de H. placei. Cada bovino recebeu 10.000 L3, de acordo com o grupo experimental, em dose única. Exames coproparasitológicos (McMaster e coproculturas) foram realizados diariamente após o 60 dia da inoculação, objetivando estabelecer o período pré-patente. Foram colhidas, semanalmente, amostras de sangue para hemogramas e dosagens bioquímicas. Decorridos 42 dias pós-infecção, os 10 bovinos foram eutanasiados e necropsiados, sendo colhido “in totum” todos os exemplares de Haemonchus. Nos abomasos foram realizados estudos anátomo-histopatológicos. O período pré patente para H. contortus foi de 20 dias e para H. placei foi de 27 dias. Dentre os parâmetros hematológicos, apenas as quantificações de hemácias apresentaram diferenças significativas (P<0,05), entre os grupos. As concentrações séricas médias de proteínas totais, albumina, ureia ...
The ovine/bovine joint breeding system, which aims for a better use of pastures, providing profitable diversification, can face severe problems in rural properties, such as parasites, amongst which Haemonchus infections stand out. H. placei and H. contortus species are commonly found parasitizing cattle and sheep, respectively. Bovine infections by H. contortus still persist as an unknown possibility in literature, especially in Brazil. Such helminth has been described parasitizing sheep and goats, while the main species cited as parasites of bovines are H. placei and H. similis. Therefore, the present study aimed to evaluate infectivity of H. contortus for bovines and compare its pathogenicity to that of H. placei. To achieve this goal, 10 calves were utilized, all created and maintained free of any contact with helminths, distributed as follows: GI – two non-inoculated calves (control group); GII – four animals inoculated with infecting larvae (L3) of H. contortus; and GIII – four bovines infected with larvae (L3) of H. placei. Each inoculated calf received 10,000 L3, according to its experimental group, in a single dose. Coproparasitological exams (McMaster and coprocultures) were performed daily, starting at the 6th post-inoculation day, seeking to establish prepatent periods. Blood samples, for cell counts and biochemical dosages, were collected on a weekly basis. 42 days after infection of experimental animals, all 10 calves were euthanized and necropsied, for subsequent “in totum” collection of all Haemonchus specimens. Anatomical and histopathological examinations were performed on all abomasums. Prepatent period for H. contortus was 20 days, and 27 days for H. placei. Amongst hematological parameters, only erythrocyte counts presented significant differences (P < 0.05) between experimental groups. Average serum concentrations of total proteins, albumin, urea, creatinin, AST and GGT presented significant ...
The ovine/bovine joint breeding system, which aims for a better use of pastures, providing profitable diversification, can face severe problems in rural properties, such as parasites, amongst which Haemonchus infections stand out. H. placei and H. contortus species are commonly found parasitizing cattle and sheep, respectively. Bovine infections by H. contortus still persist as an unknown possibility in literature, especially in Brazil. Such helminth has been described parasitizing sheep and goats, while the main species cited as parasites of bovines are H. placei and H. similis. Therefore, the present study aimed to evaluate infectivity of H. contortus for bovines and compare its pathogenicity to that of H. placei. To achieve this goal, 10 calves were utilized, all created and maintained free of any contact with helminths, distributed as follows: GI – two non-inoculated calves (control group); GII – four animals inoculated with infecting larvae (L3) of H. contortus; and GIII – four bovines infected with larvae (L3) of H. placei. Each inoculated calf received 10,000 L3, according to its experimental group, in a single dose. Coproparasitological exams (McMaster and coprocultures) were performed daily, starting at the 6th post-inoculation day, seeking to establish prepatent periods. Blood samples, for cell counts and biochemical dosages, were collected on a weekly basis. 42 days after infection of experimental animals, all 10 calves were euthanized and necropsied, for subsequent “in totum” collection of all Haemonchus specimens. Anatomical and histopathological examinations were performed on all abomasums. Prepatent period for H. contortus was 20 days, and 27 days for H. placei. Amongst hematological parameters, only erythrocyte counts presented significant differences (P < 0.05) between experimental groups. Average serum concentrations of total proteins, albumin, urea, creatinin, AST and GGT presented significant ...
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Palavras-chave
Bovino, Bovino - Infecções, Parasitismo, Haemonchus contortus, Helminto, Infection
Como citar
FÁVERO, Flávia Carolina. Viabilidade do parasitismo por Haemonchus contortus em bovinos experimentalmente infectados. 2014. x, 62 p. Dissertação (mestrado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Faculdade de Ciências Agrárias e Veterinárias, 2014.