Supressão da resposta imunitária humoral causada pela citrinina / Humoral immunosupression caused by citrinin

Avaliou-se o efeito imunotóxico causado por exposição a baixas doses de citrinina (2,5mg kg-1) em camundongos albinos expostos à micotoxina antes (n=15), durante (n=15) e após (n=15) a imunização com antígeno inerte, representado por eritrócitos de carneiro - sheep red blood cells (SRBC). Quinze camundongos foram usados como controle (não intoxicados). Sete dias após o tratamento, os animais foram sangrados e os títulos de anticorpos anti-SRBC e de complemento foram determinados. A citrinina diminuiu os títulos de anticorpos primários em todos os grupos intoxicados. A intoxicação antes e após a imunização provocou diminuição em 87,5 por cento nos títulos médios de anticorpos específicos. A exposição simultânea à imunização gerou diminuição de 75 por cento. Houve acentuada redução nos níveis de complemento circulante, detectada nos animais previamente intoxicados (93,8 por cento), ou intoxicados juntamente com a imunização (87,5 por cento).

Prevalence of anti-Neospora caninum antibodies in dogs from urban, periurban and rural areas of the city of Uberlândia, Minas Gerais--Brazil.

In Brazil there are few reports on the prevalence of anti-Neospora caninum antibodies in dogs from urban, periurban and rural areas. Serum samples from 450 dogs, 300 from urban, 58 from periurban and 92 from rural areas, were tested for the detection of anti-N. caninum IgG antibodies using IFAT: indirect fluorescent antibody test (IFAT, > or =50). Antibodies were observed in 63 (14%) of the 450 serum samples analyzed, with 32 (10.7%) in dogs coming from the urban area, 11 (18.9%) from the periurban area and 20 (21.7%) from the rural area. Statistical differences were seen between the occurrences in animals from the urban area and those of the rural area (P = 0.01). The antibody titers found were: 1:50 in 20 dogs, 1:100-1:800 in 41 dogs, and 1:3200 in two dogs. In the female dogs, a smaller prevalence of dogs with antibodies was observed in those from the urban area (7.5%) in comparison with those of the rural (21.0%) (P = 0.05) and periurban (23.3%) (P = 0.01) areas. There were growing levels of antibody prevalence with the increase in age of the dogs in all three areas studied. Although this increase was not significant, it indicates a tendency towards more infections with age, suggesting post-natal exposure to N. caninum. However, a significant difference (P = 0.05) was observed in the occurrence of anti-N. caninum antibodies in dogs with ages = 2 years in urban (13.1% urban) versus rural environments (27.1% rural). Among the other age brackets studied the difference was not significant. The results confirm the presence of N. caninum in the region and reveal the important role of dogs in the parasite's epidemiology.