Humoral immune response in dogs and cats vaccinated against rabies in southeastern Brazil

Brazil holds annual nationwide public campaigns to vaccinate dogs and cats against rabies. The presence of rabies antibodies in these animals, which are among the main transmitters of rabies to humans, is a good indicator that they are immunized and protected.Methods In the present study we analyzed 834 serum samples from dogs and cats from the Southeast of Brazil (Presidente Prudente and Dracena cities), 12 months after the 2009 vaccination campaign. We used the technique known as rapid fluorescent focus inhibition test (RFFIT) and considered reactant those sera with values higher 0.5 IU/mL. Results and discussion Reactant sample results in Presidente Prudente were 153 (51.0%) for dogs and 59 (32.6%) for cats, and in Dracena 110 (52.1%) for dogs and 71 (50.0%) for cats. We discussed vaccine coverage of animals involved in this experiment, and observed low titers < 0.5 IU/mL, especially in cats from Presidente Prudente.Conclusion According to the results presented in our experiment, we suggest that titers below 0.5 IU/mL are worrisome and that, for multiple reasons, animals should be immunized against rabies in the period between public vaccination campaigns. Hence, the desired vaccine coverage was not accomplished, especially among cats from Presidente Prudente.

Prevalence and geographical distribution of Toxoplasma gondii in dogs in the urban area of Botucatu, SP, Brazil / Prevalência e distribuição geográfica do Toxoplasma gondii em cães na área urbana de Botucatu, SP, Brasil

Toxoplasmosis is a worldwide zoonosis caused by Toxoplasma gondii, and can infect a wide variety of animals including humans. Domestic animals can be an important sentinel population for infection in the community. Occurrence of T. gondii infection was assessed in dogs in the urban area of Botucatu city, SP, Brazil. In the sample, 10% rate for error estimate, 95% confidence interval, and 5% significance level were established. Serum samples were collected from dogs during a rabies vaccination campaign, and were processed using modified agglutination test (MAT). Blood samples were collected from 670 dogs, with homogeneous distribution in five regions in the urban area, representing 3.74% of 17,910 animals vaccinated. In this sample, 17.3% (116/670) dogs (68 – 58.6% female and 48 – 41.4% male) were positive for T. gondii infection (p<0.03). Regarding age of the infected dogs 4.6% (4/88) were younger and 95.4% (84/88) were older than one year (p<0.01); the age of 28 positive animals were undetermined. The serum titers of anti-T. gondii antibodies were: 16 (69.8%; 81/116), 64 (13.8%; 16/116), 256 (15.5%; 18/116), and 1024 (0.9%; 1/116). Prevalence was distributed among the North 14.2% (19/134), South 18.0% (31/172), East 15.7% (19/121), West 21.6% (27/125), and Central 16.9% (20/118) regions of the municipality (p=0.5). In all these regions, females and dogs aged more than one year showed a higher occurrence of T. gondii infection (p<0.05).

Toxoplasmose é uma zoonose de distribuição mundial causada pelo Toxoplasma gondii, que pode infectar uma grande variedade de animais, inclusive seres humanos. Animais domésticos podem ser sentinelas importantes para infecções na comunidade. Ocorrência de infecção pelo T. gondii foi avaliada em cães na área urbana de Botucatu (SP, Brasil). Para amostragem, considerou-se uma taxa de erro na estimativa de 10%, um intervalo de confiança de 95% e um nível de significância de 5%. As amostras de sangue dos cães foram coletadas durante uma campanha de vacinação antirrábica e processadas usando-se o teste de aglutinação modificado (MAT). Foram coletadas 670 amostras de sangue, com distribuição homogênea em cinco regiões da área urbana, representando 3.74% dos 17.910 cães vacinados. Dessa amostra, 17,3% (116/670) dos cães, sendo 58,6% (68/116) fêmeas e 41,4% (48/116) machos, foram positivos para infecção pelo T. gondii (p<0,03). Entre os cães infectados 4,6%; (4/88) deles tinham idade menor e 95,4% (84/88) maior que um ano (p<0,01); em 28 animais positivos a idade não era conhecida Os títulos séricos de anticorpos anti-T. gondii estavam distribuídos entre 16 (69,8%; 81/116), 64 (13,8%; 16/116), 256 (15,5%; 18/116) e 1024 (0,9%; 1/116). Os animais positivos estavam distribuídos nas regiões Norte 14,2% (19/134), Sul 18,0% (31/172), Leste 15,7% (19/121), Oeste 21,6% (27/125) e Centro 16,9% (20/118) do município (p=0,5). Em todas essas regiões, fêmeas e animais com mais de um ano de idade tiveram maior taxa de positividade para a infecção (p<0.05).

Dog rabies in Bangkok.

Canine rabies remains a serious public health problem in Thailand. The Queen Saovabha Memorial Institute (QSMI) of the Thai Red Cross Society is the principal rabies diagnostic center in central Thailand. The retrospective study of canine rabies cases collected between 1994-1999 revealed that: (1) The prevalence of rabid dogs has decreased, and was associated with an overall decrease in the number of animals submitted for examination. However, the percentages of dogs with positive Fluorescent antibody test (FA) remained the same at approximately 40 per cent. (2) About 62 per cent of rabid dogs were less than one year old. Dogs at this age are more active and most have not been adequately vaccinated. Approximately 80 per cent of rabid dogs had never been vaccinated against rabies.

Effect of inactivated viral vaccines (human) on frequency of micronuclei in bone marrow erythrocytes of mice.

Cytogenetic effects of the two inactivated viral vaccines (polio and antirabies) were studied in adult male mice by the micronucleus test. Polio salk vaccine did not induce micronuclei formation at both human (0.5 ml) and 1/5th human doses. Antirabies vaccine induced micronuclei in poly and total erythrocytes only at human dose of 2 ml. Beta-propiolactone (BPL) induced micronuclei at higher dose of 5.7 mg, but not at 0.57 mg (approximate concentration present in 2 ml of rabies vaccine). The P/N ratio was not affected in vaccinated and BPL inoculated animals. Antirabies vaccine induced micronuclei percentage was more than the BPL value.