A total of 117 blood samples from birds (n = 79), amphibians (n = 4) and reptiles (n = 34) were collected from Pattoki (Punjab province) and Karachi region (Sindh province) of Pakistan. Out of 117, 13 (11.1%) samples were seropositive for
Brucella antibodies (Table 1). Overall, 2.5% avian, 29.4% reptiles and 25% amphibian samples were diagnosed seropositive for brucellosis using RBPT. However, seroprevalence of
Brucella antibodies was 6.25% in peafowl and 9.1% in Indian blue rock pigeons. In case of reptiles, 32.3% (n = 10) yellow spotted mud turtles were seropositive for
Brucella antibodies. In amphibians, 25% seroprevalence was recorded in Indian bullfrogs. Moreover, gender-based variation was observed in
Brucella antibodies in seropositive birds and wildlife animals (Table 2).
In the present study, we investigated the presence of
Brucella antibodies in different wildlife animal species and avian species from Karachi and Pattoki regions of Pakistan. Overall seroprevalence of
Brucella antibodies was 11.1% using RBPT. The seropositive reactors presented in the study consist of 2.5% birds, 29.4% reptiles and 25% amphibians.
In case of birds, the Indian blue rock pigeon showed the highest incidence of infection 9.1% while the peafowl had least seroprevalence (6.25%). The results might be the reflection of the level of immunity variation against brucellosis in different birds. The results obtained here were higher than the 4% reported by
Ahmad and Munir (1995) on domestic birds from Pakistan and lower than the 10.8% and 14.6% for free range birds recorded by
Bale and Nuru (1982) in northern Nigeria. The differences in findings might be due to environmental conditions and management practices in those locations. The epidemiologic importance of the 9.1% and 6.25% positive reactions in this work in pigeons and peafowl, and the results found in birds i.e. 2.8% in pigeons, 2.3% in chicken and in 1.9% Muscovy ducks by
Alaga et al., (2012), showed that birds in these areas of study are raised side by side with other domestic animals and closeness with man particularly at their homes, market areas and other public places might be reason of cross infections.
Brucella infection might spread in the same species and to other birds and livestock by infected feces (
Shehu and Ehitade, 1999). This evidence was further proved from isolation of
Brucella melitensis from fresh water Nile Catfish (
Clarias gariepinus) from Nile canals in Egypt which was heavily contaminated due to disposal of animals waste
(El-Tras et al., 2010). Moreover, the excreta also pose a hazard for humans particularly as chicken feces are generally collected for use as fertilizer and the organism may be inhaled in form of vaporizer or dust in the process
(Gugong et al., 2012).
Yellow spotted mud turtles and bullfrogs were seropositive for
Brucella antibodies in the present study. The presence of
Brucella antibodies in different wild animal species might be due to its survival for a number of months in soil and dung which increases the chance of cross species infection
(Scholz et al., 2008; Aune et al., 2011). There are studies describing the isolation of
Brucella inopinata and motile
Brucella-like coccoid bacteria from wild-caught African bullfrogs (
Pyxicephalus edulis) and White’s tree frogs (
Litoria caerulea), respectively
(Dominik et al., 2012; Eisenberg et al., 2012;
Whatmore et al., 2015). However, interestingly, there was no record on the presence of brucellosis in reptiles up to our knowledge. Our study is the first report on the presence of
Brucella antibodies in reptiles. The presence of brucellosis in amphibians and reptiles is very important and interesting in terms of ecological studies. Because these species might act as potential reservoirs, which increase the risk of brucellosis to human handing of these species and livestock has contact with these animals in grazing area. Apart from these wildlife animals, evidences of brucellosis exist in other wild species from different regions: shrew, red foxes etc.
(Scholz et al., 2009; Hammer et al., 2017).
In conclusion, brucellosis is a zoonotic disease that has a major socio-economic, veterinary and public health impact in many areas of the world. The present study first indications of the presence of brucellae in reptiles, amphibians and avian species in this country. However, human and livestock brucellosis was already documented for Pakistan. The presence of brucellosis in these apparently non-target species (reptiles, amphibians and birds) is an indication of the diversification of the host range of brucellae in Pakistan. This is also an alarming condition in a country like Pakistan where there is no control or eradication of animal brucellosis. Moreover, the presence of brucellosis in reptiles, amphibians and avian species not only increases the risk of said disease for livestock but also for human beings having close contact with these livestock animals and those involved in handing of wild animals and wild birds. There is dire need for the investigation of brucellosis in apparently non-target species to minimize the risk of cross species transmission of brucellosis in livestock and the human population of Pakistan.
