Résumé
A trial was conducted to compare the cellular responses in the respiratory tract in intranasal vaccination against caprine Peste des petits ruminant lineage 1 variant virus infection with intramuscular and subcutaneous vaccinations in order to elucidate the mechanism of the protection. Twenty four goats were divided into four equal groups. Group 1 was vaccinated intranasaly, group 2 was vaccinated subcutaneously, and group 3 intramuscularly, while Group 4 was the unvaccinated control group. In each group the vaccinations were carried out once. All goats were challenged intratrachealy with PPR virus at a concentration of 106.5 TCID50 two weeks after vaccination and were euthanised 21 days after the challenge. The bronchoalveolar lavage differential count, bronchial associated lymphoid tissue (BALT) responses were measured using standard techniques. Descriptive Statistics and ANOVA was employed and significance was at p < 0.05. The exposure also resulted into significant increase in the number and size of BALT as well as the number of lymphocytes in BALT. This study showed the mechanism of the protective effect of intranasal vaccination of PPR vaccine observed with the strong mucosal and defensive cellular responses in the respiratory tract observed than the subcutaneous and intramuscular routes.
Se realizó un ensayo para comparar las respuestas celulares en las vías respiratorias después de la vacunación intranasal contra la variante caprina de la infección del virus peste de pequeños rumiantes linaje 1 con vacunas intramusculares y subcutáneas con el fin de dilucidar el mecanismo de protección. Veinticuatro cabras fueron divididas en cuatro grupos iguales. El Grupo 1 fue vacunado por vía intranasal, el grupo 2 vía subcutánea, el grupo 3 vía intramuscular y el grupo 4 control no vacunado. En cada grupo se vacunó sólo una vez. Todas las cabras fueron expuestas al virus peste de pequeños rumiantes por vía intratraqueal a una concentración de 106.5 TCID50 2 semanas después de la vacunación, y fueron sometidos a eutanasia 21 días después. Se midieron el recuento diferencial del lavado broncoalveolar y las respuestas de los tejidos linfoides asociados bronquios (BALT) utilizando técnicas estándar. Los resultados se evaluaron por estadística descriptiva y ANOVA, con una significación p<0,05. La exposición también mostró un aumento significativo en el número y tamaño del BALT, así como el número de linfocitos en este. El estudio mostró que el mecanismo del efecto protector de la vacunación intranasal contra el virus peste de pequeños rumiantes posee una respuesta mucosa y celular defensiva en el tracto respiratorio mayor que la observada por vacunación vía subcutánea e intramuscular.
Sujets)
Mâle , Animaux , Femelle , Administration par voie nasale , Capra , Peste des petits ruminants/prévention et contrôle , Appareil respiratoire , Vaccins antiviraux/administration et posologie , Analyse de variance , Vaccins atténués/administration et posologieRésumé
BACKGROUND & OBJECTIVES: The prevalence of trypanosomiasis was studied in cattle, being a major source of animal protein in Nigeria, thus, a very likely means of spread of Human African Trypanosomosis (HAT). METHODS: Enzyme-linked immunosorbent assay (ELISA) was used to diagnose bovine trypanosomiasis in 264 samples collected from adult cattle of mixed breeds, age and sex, in Anambra and Imo states, Nigeria. RESULTS: Out of 264 samples analysed, 21 (7.96%) were seropositive for Trypanosoma congolense while 20 (7.58%) were seropositive for T. vivax and 8 (3.03%) were seropositive for T. brucei infections in both the states. INTERPRETATION & CONCLUSION: The predominant species was found to be T. congolense. Mixed infection of three species, T. vivax, T. congolense and T. brucei was found to dominate other mixed infections in both the states. ELISA detected the infection of the three species of trypanosomes in the same group of animals. The usefulness of antigen capture ELISA in the diagnosis of human or animal trypanosomiasis was established, and the possibility of the spread of HAT caused by T. brucei gambiense and T.b. rhodesiense through cattle was expressed.