23 January 2021
Souleymane Traoré, Veterinary Doctor from Mali and Afrique One-ASPIRE fellow, conducted a study on the seroprevalence of brucellosis in small ruminants and associated risk behaviors leading to infections in humans in different livestock systems in Mali.
The study was carried out in three regions of Mali (Sikasso in the south, Ségou in the center and in the district of Bamako in the southwest). The objectives were to determine the role of small ruminant husbandry systems in maintaining and transmitting brucellosis in the country. Specifically, the study aimed to assess the seroprevalence of brucellosis and to show how the husbandry system and the associated human behaviour expose animals and humans to the disease.
His results are published in the scientific journal Plos One, freely accessible to all. Here the PhD candidate Souleymane Traoré from the École Inter-États des Sciences et Médecine Vétérinaires de Dakar, Sénégal, reveals that brucellosis, a disease causing abortion in animals and fever and malaise in humans, which is transmissible between animals and humans (zoonosis), can be an obstacle to the development of livestock farming in Mali.
Unfortunately, brucellosis control is neglected in Mali and has been the subject of only a few studies.
The existing studies on brucellosis in Mali have demonstrated relatively high infection rates (seroprevalence), but so far did not take into account the breeding system aspect or the identification of risk behaviour for transmission. The mechanisms underlying the transmission of this zoonosis are rather complex. In order to update the epidemiological situation on brucellosis in Mali and to understand the elements that promote its spread and maintenance in farming systems, studies like this are essential.
Traore’s recent study found a high seroprevalence of brucellosis in small ruminants at the individual level (4.1%), which is an indicator that a high number of animals are infected. Overall 25.2% of small ruminant herds in this study were infected.
When looking at the husbandry system, the peri-urban farming system was most affected with a seroprevalence of 38.1%, followed by the pastoral farming system (24.3%). Practices risking infection of animals through cross transmission between the two populations were identified.
The exchange of reproductive males between farmers was observed in 30.2% of farms. Improper disposal of placentas on the farm was observed in 31.1% of farms. Also, keeping females in the herd that have aborted was reported by 69.7% of breeders. These practices could promote contamination of animals and thus maintain brucellosis in the herd.
Behaviours that could expose humans to brucellosis have been observed, such as close and prolonged contact with animals in 51.2% of cases, the consumption of unpasteurized dairy products (26.9%); and assisting female animals during delivery without any protective equipment in 40.3% of farms.
This study was limited by the fact that no blood was collected from humans to elucidate possible links between animal and human seropositivity. Also, the exact strains of Brucella circulating in small ruminants have not been identified.
It would be important to carry out similar studies including the determination of the prevalence of brucellosis in humans and seek to isolate and identify strains of Brucella spp. circulating on small ruminant farms in Mali.
About Afrique One-ASPIRE:
The Afrique One Consortium is a group of African scientists working in universities and research institutions in both East and West Africa. They collaborate with universities in the UK and Switzerland and their research work is funded by the Kenyan-based African Academy of Sciences under the DELTAS Africa research and training program.
Publication available here:https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0245283