Estimating the prevalence of Brucellosis in cattle in Zimbabwe from samples submitted to the Central Veterinary Laboratory between 2010 and 2014.

Brucellosis is a disease caused by bacteria belonging to the genus Brucella, which is endemic in sub-Saharan African countries, including Zimbabwe. Zimbabwe has a widespread dairy industry with peri-urban dairy establishments built in order to improve milk availability to rural communities. This study has been the first attempt to estimate the prevalence of brucellosis in Zimbabwe as a whole, using samples submitted to the Central veterinary laboratory between 2010 and 2014. A total of 156 farms were tested with Rose Bengal Test (RBT), Complement Fixation Test (CFT) and Milk Ring Test (MRT). Parallel testing was used to determine whether or not a farm was to be considered positive: 30.1% (95% C.I.: 23.5% - 37.8%) of the farms tested were found positive (47/156). Harare district had the highest number of sample submissions with 6 out of 17 farms testing positive (P = 37.5%; 95% C.I.: 18.4% - 61.7%). Awareness of milk-borne zoonoses is reportedly generally low in farmers (41.5%). This is even more the case in small-holder farmers who have higher likelihoods of selling or ingesting raw milk compared with dairy farmers. The results show the need to carry out surveillance of brucellosis in cattle in Zimbabwe to understand the spatial distribution of the disease in the country. This is particularly relevant given the zoonotic and economic implications of this disease.

Antibacterial activity of aqueous and methanol extracts of selected species used in livestock health management.

CONTEXT: Salvadora persica L. (Salvadoraceae), Colophospermum mopane (J.Kirk ex Benth.) J. Léonard (Leguminosae) and Dichrostachys cinerea (L.) Wight & Arn. (Leguminosae) crude extracts are used by local farmers against many livestock infections with little or no side effects usually associated with synthetic antimicrobials. However, their efficacy has rarely been tested. OBJECTIVE: These plants were tested for potential antibacterial activity against clinical isolates of Staphylococcus aureus ATCC33862 and Escherichia coli ATCC25922. Minimal inhibitory concentrations (MIC) of the crude plant extracts were determined. MATERIALS AND METHODS: Aqueous and methanol extraction of 100 g each of the bark of C. mopane, roots of D. cinerea and leaves of S. persica was done by placing the samples in 250 mL of either water or methanol. Nutrient broth was used as growth medium for the bacteria, and McFarland standard for bacterial standardization. 2,3,5-Triphenyltetrazoliumchloride (TTC) was the indicator salt. Each of the aqueous and methanol extracts (100 µL) was tested. Gentamycin and ampicillin were the controls. RESULTS: MIC of aqueous extracts ranged from 1.03-14.6 mg/mL against S. aureus, and from 12.1-34.3 mg/mL against E. coli. Methanol extracts ranged between 5.31 and 9.64 mg/mL against S. aureus, and between 7.86 and 13.6 mg/mL against E. coli. Aqueous and methanol extracts of S. persica were significantly higher (p < 0.05) than C. mopane and D. cinerea. DISCUSSION AND CONCLUSION: Colophospermum mopane, S. persica and D. cinerea exhibited antibacterial activity, with methanol extracts performing better than aqueous extracts, justifying use as ethnoveterinary medicine. Further study to isolate the active components should be pursued.