RESUMO
Control of Haemonchus placei, one of the most important cattle nematodes in Brazil, relies on the use of anthelmintics. However, there is a need for integrated control, which includes active immunization. The aim of this work was to assess the protection afforded to calves by immunization with adult H. placei extracts against a high-dose challenge infection, a condition frequently found in the tropics. Holstein calves aged 8-10 months were immunized four times with intestinal extracts (Group D) or with a Triton X-100-soluble fraction of adult H. placei (Group A), challenge-infected with 120,000 infective larvae and sacrificed 40 days later. Immunized animals had higher IgG titers than the controls against tested fractions after the 2nd immunization, peaking after the 4th. Sera from both immunized groups recognized bands of similar apparent mass in both antigenic preparations, some of which were similar in molecular weight to Haemonchus contortus antigens with known protective effect to sheep. Egg counts were 49% and 57% lower in Groups A and D than in controls, respectively. High levels of protection were observed in two of the four calves in Group D, as evidenced by very low worm numbers recovered at necropsy, absence of eggs in the uteri of the recovered females and reduced worm length. Group D animals also showed milder signs of anemia than the other infected animals. Results demonstrate that protection against homologous high-dose challenge can be achieved by immunizing calves with H. placei gut antigens.
Assuntos
Antígenos de Helmintos/imunologia , Doenças dos Bovinos/prevenção & controle , Hemoncose/veterinária , Haemonchus/imunologia , Imunização/veterinária , Animais , Anticorpos Anti-Helmínticos/sangue , Antígenos de Helmintos/administração & dosagem , Bovinos , Doenças dos Bovinos/parasitologia , Feminino , Hemoncose/prevenção & controle , Haemonchus/química , Imunoglobulina G/sangue , Intestinos/química , Masculino , Membranas/química , Contagem de Ovos de Parasitas/veterinária , Distribuição Aleatória , Fatores de TempoRESUMO
Undergraduate teaching of veterinary parasitology in South American countries is basically similar to most of the veterinary schools and offers lectures and practicals in parasitology (P) predominantly in the second year of the curriculum, and parasitic diseases (PD) in the third year, but in some schools also in the fourth and fifth years. However, there is a great variation in teaching hours allocated to P/PD between totals of about 50-169 h during the full curriculum. In addition to the lectures and practicals, schools are increasingly using tools (CD-ROMs) for self-instruction and new forms of education, such as workshops, round tables, and field practicals. The large number of important parasite species of large and small animals in tropical and subtropical areas would require additional hours for teaching--at least in some of the schools--considering the multidisciplinary characteristics of veterinary parasitology.
Assuntos
Educação em Veterinária , Parasitologia/educação , Ensino/métodos , Animais , Brasil , Instrução por Computador/métodos , Educação em Veterinária/tendências , Humanos , Faculdades de Medicina Veterinária , América do SulRESUMO
In vitro tests were carried out to verify the activity of 26 Brazilian isolates of predatory fungi of the genus Arthrobotrys on a free-living nematode (Panagrellus sp.) and on infective larvae of Cooperia punctata, a parasitic gastrointestinal nematode of cattle. The results showed that the free-living nematode Panagrellus sp. was the most preyed upon, compared to C. punctata, for all the fungal treatments. Also, variable predatory capacity was observed for different fungal isolates belonging to the same genus when applied to different nematode species.
Assuntos
Fungos Mitospóricos/patogenicidade , Nematoides/microbiologia , Controle Biológico de Vetores , Animais , Bovinos , Larva , Fungos Mitospóricos/isolamento & purificação , Especificidade da EspécieRESUMO
In vitro tests were carried out to verify the activity of 26 Brazilian isolates of predatory fungi of the genus Arthrobotrys on a free-living nematode (Panagrellus sp.) and on infective larvae of Cooperia punctata, a parasitic gastrointestinal nematode of cattle. The results showed that the free-living nematode Panagrellus sp. was the most preyed upon, compared to C. punctata, for all the fungal treatments. Also, variable predatory capacity was observed for different fungal isolates belonging to the same genus when applied to different nematode species
Assuntos
Animais , Bovinos , Técnicas In Vitro , Fungos Mitospóricos/patogenicidade , Nematoides/microbiologia , Larva , Fungos Mitospóricos/isolamento & purificação , Controle Biológico de VetoresRESUMO
In vitro tests were carried out to assess the activity of 26 Brazilian isolates of predatory fungi of the genus Arthrobotrys on a free-living nematode (Panagrellus sp.) and on infective larvae of Haemonchus placei, a parasitic gastrointestinal nematode of cattle. The results showed that the free-living nematode Panagrellus sp. was the most preyed upon, compared to H. placei, for all the fungal treatments. Also, variable predatory capacity was observed for different fungal isolates belonging to the same genus when applied to different nematode species
Assuntos
Animais , Bovinos , Técnicas In Vitro , Fungos Mitospóricos/patogenicidade , Nematoides/microbiologia , Brasil , Haemonchus/microbiologia , Fungos Mitospóricos/isolamento & purificação , Comportamento PredatórioRESUMO
In vitro tests were carried out to assess the activity of 26 Brazilian isolates of predatory fungi of the genus Arthrobotrys on a free-living nematode (Panagrellus sp.) and on infective larvae of Haemonchus placei, a parasitic gastrointestinal nematode of cattle. The results showed that the free-living nematode Panagrellus sp. was the most preyed upon, compared to H. placei, for all the fungal treatments. Also, variable predatory capacity was observed for different fungal isolates belonging to the same genus when applied to different nematode species.
Assuntos
Haemonchus , Fungos Mitospóricos , Nematoides , Controle Biológico de Vetores , Animais , Brasil , BovinosRESUMO
The dynamics of the humoral immune response of calves were analysed after primary infection and re-infection with the intestinal nematode Cooperia punctata. 12 male 5 month-old Holstein-Friesian calves were randomly divided into two groups A and B. At the beginning of the experiment Group A animals were each infected experimentally with a single oral dose of 130,000 infective third stage larvae (L3) of C. punctata. The animals of Group B were kept as non-infected controls. The two calves from Group A with the highest infections died of cooperiosis at 32 and 44 days after infection (DAI), respectively. On DAI 100 the calves were treated with the recommended dose of oxfendazole. On DAI 180 the remaining four calves of Group A and three animals of Group B (B1) were infected with 260,000 L3 of C. punctata, while the other three calves of Group B (B2) served as non-infected controls. Monitoring of the humoral immune response predominantly demonstrated an IgG1 response against both adult and L3 antigen of C. punctata. Moreover, re-infections increased the levels of these immunoglobulins. IgA levels were less increased than IgG1 and no significant increase was observed in IgG2 and IgM levels. Immunoblotting analysis showed that total IgG present in the serum of the primary infected animals mainly reacted against adult proteins of 12-14 and 17-20 kDa and against L3 proteins of 33 and 43 kDa. After re-infection total IgG reacted with the same adult proteins but also with an adult 29 kDa protein.
Assuntos
Anticorpos Anti-Helmínticos/biossíntese , Doenças dos Bovinos/imunologia , Tricostrongiloidíase/veterinária , Animais , Bovinos , Eletroforese em Gel de Poliacrilamida/veterinária , Ensaio de Imunoadsorção Enzimática/veterinária , Fezes/parasitologia , Masculino , Contagem de Ovos de Parasitas/veterinária , Distribuição Aleatória , Recidiva , Tricostrongiloidíase/imunologiaRESUMO
Dois grupos de cinco bezerros, das raças Holandesa e Nelore, com idade aproximada de nove meses, receberam por via oral uma dose única de 1.000 larvas infectantes (L3) por kg de peso corporal de Haemonchus placei. Os animais foram mantidos sob observaçäo clínica após a infecçäo. Amostras de sangue foram coletadas semanalmente por punçäo venosa, desde uma semana antes, até a oitava semana pós-infecçäo. Os estudos hematológicos abrangeram hematócrito, contagem diferencial de leucócitos, determinaçöes de hemoglobina, fibrinogênio e proteínas plasmáticas. Os exames parasitológicos compreenderam exames de fezes semanais com contagem de ovos (OPG) e estimativa de cargas de vermes na necropsia. Amostras de tecido da mucosa do abomaso foram submetidos a estudos histopatológicos. Ambos os grupos mostraram números crescentes de OPG após a quinta semana, sendo que os bezerros de raça Holandesa apresentaram maiores contagens do que os da raça Nelore. Na terceira semana pós-infecçäo e até o final do experimento, os bezerros da raça Holandesa tiveram anemia e hipoproteinemia, enquanto que os bezerros Nelore näo apresentaram alteraçöes significativas desses parâmetros. A necropsia, os bezerros da raça Holandesa apresentaram uma carga de vermes significativamente maior dos que os da raça Nelore. As alteraçöes patológicas visíveis e lesöes histopatológicas foram similares, embora macroscopicamente fossem levemente mais evidentes na raça Holandesa. Estes resultados demonstram que bezerros da raça Holandesa säo mais susceptíveis à infecçäo e aos efeitos patogênicos de H. placei do que bezerros da raça Nelore