A serological survey to determine the prevalence of Brucella Canis infection in dogs within the Nelson Mandela Bay metropolitan in the Eastern Cape, South Africa

Abstract

The prevalence of Brucella canis in South Africa is unknown and suspected to be under-detected. The majority of dogs in South Africa are not tested for Brucella canis, not only because of the level of awareness of Brucella canis in South Africa, but also because of the lack of clinical suspicion. It is not known how the infection entered South Africa. Brucella canis, a zoonotic organism that causes canine brucellosis in dogs, is a significant cause of reproductive failure in dogs worldwide. Canine brucellosis is a chronic infectious zoonotic disease whose main etiological agent, the Brucella canis bacterium, are rough, intracellular proteobacteria in the Brucellaceae family. Clinical signs in bitches are mainly infertility and abortion, while in males, epididymitis and orchitis occur. However, discospondylitis may develop in both sexes. A serological survey was conducted to determine the prevalence of Brucella canis infection in dogs from the Nelson Mandela Bay Metropolitan (NMBM) Port Elizabeth (PE) area. A total of 400 samples were collected, 350 of which were collected in seven different townships and 50 were collected in the three different welfare organisations in the study area. Of the 400 serum samples collected, 39 (9.75%) tested serologically positive by using the Tube Agglutination Test (TAT), the 2-Mercaptoethanol-TAT (2ME-TAT) or the Compliment Fixation Test (CFT). The results of the CFT showed that nine of the 39 positive samples had a maximum antibody titre of 784 IU/ml. The prevalence rate varied tremendously between the samples from the townships and those from the welfare organisations. The prevalence rate of seropositive animals in PE ranged between 5% and 16% in the study area. No positive cases were found in KwaMagxaki and the Animal Welfare Society of PE, but both were surrounded by areas that had positive cases of Brucella canis infection. The female dogs in the study area had a higher sero-prevalence of only 0.0169 (95% CI, 0.0631 to 0.1489) differences in proportion, and were thus not significant (p > 0.05). However, the female spayed dogs had a much higher significant difference of 0.1898 (95% iv CI, 0.1058 to 0.2738) in proportion to the male neutered dogs and were thus statistically significant (p < 0.05). Despite those results, out of all the dogs positive for Brucella canis only two were neutered males and five were spayed females, and the rest were all intact. In conclusion, according to the results, Brucella canis antibodies were detected in sera of dogs mostly from the townships surveyed. Preventive measures against this contagion should be taken into consideration to eliminate Brucella canis infection from the entire dog population. Reservoir dogs and actively infected dogs either should be kept in quarantine or should be euthanized, because not only can they spread the disease and end the reproductive life of any breeding animal, but they are also a risk to human health. Even though this is the first survey conducted in the Eastern Cape, the results are still high dogs in the study area had a higher sero-prevalence of only 0.0169 (95% CI, 0.0631 to 0.1489) differences in proportion, and were thus not significant (p > 0.05). However, the female spayed dogs had a much higher significant difference of 0.1898 (95% iv CI, 0.1058 to 0.2738) in proportion to the male neutered dogs and were thus statistically significant (p < 0.05). Despite those results, out of all the dogs positive for Brucella canis only two were neutered males and five were spayed females, and the rest were all intact. In conclusion, according to the results, Brucella canis antibodies were detected in sera of dogs mostly from the townships surveyed. Preventive measures against this contagion should be taken into consideration to eliminate Brucella canis infection from the entire dog population. Reservoir dogs and actively infected dogs either should be kept in quarantine or should be euthanized, because not only can they spread the disease and end the reproductive life of any breeding animal, but they are also a risk to human health. Even though this is the first survey conducted in the Eastern Cape, the results are still high