Sero-prevalence of brucellosis, Q-fever and Rift Valley fever in humans and livestock in Somali Region, Ethiopia.

Information on zoonotic diseases in humans and livestock are limited in pastoral/agro-pastoral communities in Ethiopia. A multi-stage cross sectional cluster design study was implemented with the aim to establish the seroprevalence of zoonotic diseases including brucellosis, Q-fever and Rift Valley fever (RVF) in humans and livestock in Adadle Woreda of the Somali Region, Ethiopia. Blood samples were collected from humans and livestock and tested by relevant serological tests. For brucellosis, Rose Bengal test (RBT) and indirect ELISA was used for screening and confirmatory diagnosis respectively. Indirect and competitive ELISA were also used for Q-fever and RVF respectively. The individual seropositivity of Q-fever in livestock was 9.6% (95% CI 5.9-15.1) in cattle, 55.7% (95% CI 46.0-65.0) in camels, 48.8% (95% CI 42.5-55.0) in goats, and 28.9% (95% CI 25.0-33.2) in sheep. In humans, seropositivity of Q-fever was 27.0% (95% CI 20.4-34.0), with prevalence in males of 28.9% vs 24.2% in females (OR = 1.3; 95% CI 0.6-2.5). Camel seropositivity of Q-fever was significantly associated with age (OR = 8.1; 95% CI 2.8-23.7). The individual apparent seroprevalence of RVF was 13.2% (95% CI 8.7-18.8) in humans, 17.9% (95% CI 11.0-27.8) in cattle, 42.6% (95% CI 34.8-50.7) in camels, 6.3% (95% CI 3.3-11.6) in goats and 7.4% (95% CI 4.7-11.5) in sheep. Camels had the highest seropositivity of both Q-fever and RVF. Only a weak correlation was observed between human and livestock seropositivity for both Q-fever and RVF. Only cattle and camels were seropositive for brucellosis by iELISA. The individual seroprevalence of brucellosis was 2.8(0.9-6.4) in humans, 1.5% (95% CI 0.2-5.2) in cattle and 0.6% (95% CI 0.0-3.2) in camels. This study showed the importance of zoonoses in Somali Region and is the first published study to describe RVF exposure in humans and livestock in the country. Even though human exposure to RVF virus was reported, public health sector of Somali Region has not given attention to such zoonoses. Collaboration between public and animal health sectors for further investigation on these zoonoses using the One Health concept is indispensable.

Melioidosis in Africa: Time to Uncover the True Disease Load.

Melioidosis is an often fatal infectious disease with a protean clinical spectrum, caused by the environmental bacterial pathogen Burkholderia pseudomallei. Although the disease has been reported from some African countries in the past, the present epidemiology of melioidosis in Africa is almost entirely unknown. Therefore, the common view that melioidosis is rare in Africa is not evidence-based. A recent study concludes that large parts of Africa are environmentally suitable for B. pseudomallei. Twenty-four African countries and three countries in the Middle East were predicted to be endemic, but no cases of melioidosis have been reported yet. In this study, we summarize the present fragmentary knowledge on human and animal melioidosis and environmental B. pseudomallei in Africa and the Middle East. We propose that systematic serological studies in man and animals together with environmental investigations on potential B. pseudomallei habitats are needed to identify risk areas for melioidosis. This information can subsequently be used to target raising clinical awareness and the implementation of simple laboratory algorithms for the isolation of B. pseudomallei from clinical specimens. B. pseudomallei was most likely transferred from Asia to the Americas via Africa, which is shown by phylogenetic analyses. More data on the virulence and genomic characteristics of African B. pseudomallei isolates will contribute to a better understanding of the global evolution of the pathogen and will also help to assess potential differences in disease prevalence and outcome.

Potential of cell-free supernatants from cultures of selected lactic acid bacteria and yeast obtained from local fermented foods as inhibitors of Listeria monocytogenes, Salmonella spp. and Staphylococcus aureus.

BACKGROUND: Food-borne infections cause huge economic and human life losses worldwide. The most common contaminants of foods include Listeria monocytogenes Salmonellae and Staphylococcus aureus. L. monocytogenes is most notorious due to its tolerance to common food preservation methods and the risks it poses, including higher fatality rates. Safer, more efficacious control methods are thus needed. Along with food-borne pathogens, lactic acid bacteria (LAB) can also be found in foods. Some LAB isolates inhibit pathogenic bacteria by various mechanisms, including by production of antimicrobial metabolites. METHODS: The potential of cell-free culture supernatants (CFS) derived from broth cultures of selected local LAB and yeast isolates, some of which were subjected to various treatments, were tested for inhibition of L. monocytogenes, Salmonella spp. and S. aureus in in vitro culture by incorporating various proportions of the CFSs into the growth medium concurrently with inoculation (co-cultures) or following limited proliferation after inoculation of the pathogens (delayed cultures). The effects of the CFSs on various growth parameters were assessed. RESULTS: CFS from the LAB isolates were strongly inhibitory when co-cultured. The inhibitory activities were stable following heat or protease treatment of the CFSs. Inhibitory activity was dependent primarily on active substance(s) secreted into the supernatant. In all co-cultures, CFS proportion-dependent progressive decrease in the number of colonies was observed and both growth rates and number of generations were reduced with significantly fewer numbers of colony forming units, whereas generation times were significantly increased compared to those of controls. Transfer from co-cultures to fresh broth showed inhibited cultures contained bacteria that can re-grow, indicating the presence of viable bacteria that are undetectable by culture. Growth rates in CFS-treated delayed cultures were also reduced to varying degrees with the number of colonies in some cultures being significantly less than the corresponding control values. CFSs were active against both Gram-positive and -negative bacteria. CONCLUSIONS: Active metabolites produced and secreted by LAB into the growth medium were effective in inhibiting the tested pathogens. Early addition of the CFSs was necessary for significant inhibition to occur. Further studies will help make these findings applicable to food safety.