Brucella seroprevalence of the Kafue lechwe (Kobus leche kafuensis) and Black lechwe (Kobus leche smithemani): exposure associated to contact with cattle.

We investigated Brucella seroprevalence in Kafue (Kobus leche kafuensis) and Black (Kobus leche smithemani) lechwe antelopes to assess Brucella infections in relation to presence/absence of cattle interaction on the wetlands. Accordingly, two study populations based on cattle interaction were assesed: Kafue lechwe from Kafue flats which interact with cattle; and the Black lechwe with no known interaction with cattle from the Bangweulu swamps. Fourteen Kafue lechwe and thirty Black lechwe were slaughtered between October and December 2009 using special research licenses obtained from the Zambia wildlife authority to investigate diseases in lechwe antelope. For the purpose of this study, blood was collected and sera separated for Rose Bengal and indirect ELISA tests. Seroprevalence of Brucella in the Kafue lechwe was estimated at 42.9% [95% CI: 15.2-70.5] while that in Black lechwe was 0% [95% CI:0.0-11.6]. On the Kafue flats, cattle were spotted grazing in the same areas as lechwe while there was no evidence of cattle presence on the Bangweulu swamps. These differences in seroprevalence between Kafue lechwe and Black lechwe were assumed to be associated with interaction between Kafue lechwe and Brucella infected cattle, and no such contact existed between cattle and the Black lechwe. Our study suggests that brucellosis in the Kafue lechwe may have originated from cattle but has now established a reservoir in wild animals. It is also important to keep in mind that the Black lechwe can easily become infected with Brucella spp. once cattle are introduced in the surrounding areas.

Tuberculosis in Kafue lechwe antelopes (Kobus leche Kafuensis) of the Kafue Basin in Zambia.

Tuberculosis (TB) has been reported in the Kafue lechwe antelopes (Kobus leche Kafuensis) of Zambia. However, previous reports are restricted to the southern parts in Lochinvar, where only old male animals were investigated. This study was conducted to gather epidemiological information on TB in Lechwe antelopes across sexes and age groups in relation to other explanatory variables of disease occurrence in the Kafue Basin. Animals were hunted under a special licence to investigate diseases in the Kafue Basin during the 2004, 2005 and 2008 hunting seasons. Histopathology, acid-fast staining and mycobacterial culturing from tissue samples were conducted. A total of 119 animals were slaughtered with an estimated age range of 2.5-20 years. Of these, 29 (24.3% [95% CI: 16.5, 32.3%]) had necropsy lesions suggestive of tuberculosis, of which 21 (17.6% [95% CI: 10.7, 24.6%]) tested positive on acid-fast staining while 33 (27.7% [95% CI: 19.6, 35.9%]) showed culture and colony morphological characteristics suggestive of Mycobacterium species. On univariate analysis, animals with poor body condition were twice as likely to have tuberculosis associated lesions as those having good body conditions (OR=2.3, 95% CI: 0.6, 9.3%). Based on lesion distribution, a respiratory route of mycobacterial infection is intimated.

Prevalence of antibodies to Brucella spp. and individual risk factors of infection in traditional cattle, goats and sheep reared in livestock-wildlife interface areas of Zambia.

A cross-sectional study was performed in the livestock-wildlife interface areas of Lochinvar and Blue Lagoon National Parks and the non-interface area of Kazungula to determine the prevalence of antibodies to Brucella spp. in domestic ruminants and identify individual animal risk factors of infection. A total of 1245 cattle from 124 herds and 280 goats and sheep from 29 flocks were tested sequentially for Brucella antibodies using the Rose Bengal test (RBT) and competitive ELISA. In cattle, individual seroprevalence ranged from 14.1% to 28.1%, while herd sero-prevalence ranged from 46.2% to 74.0% in the three study areas. No goat or sheep tested positive for Brucella antibodies. Three types of cattle grazing strategies were encountered: locally grazed herds (LGH), transhumantly grazed herds (TGH) and river flood plain grazed herds (FGH). Brucella seroprevalence was seen to vary according to area and grazing strategy: Lochinvar and transhumant grazed herds recorded the highest figures, respectively. Age, sex and history of abortion were found to have independent effects on individual seroprevalence. This study establishes that brucellosis is endemic in domestic animals in the livestock-wildlife interface areas of Blue Lagoon and Lochinvar national parks and the disease is also present in Kazungula. We observed that type of grazing strategy had significant impact on cattle Brucella seroprevalence and that transhumant herds were at high risk of being infected.