Differences in genetic structure assessed using Y-chromosome and mitochondrial DNA markers do not shape the contributions to diversity in African sires.

Up to 173 African sires belonging to 11 different subpopulations representative of four cattle groups were analysed for six Y-specific microsatellite loci and a mitochondrial DNA fragment. Differences in Y-chromosome and mtDNA haplotype structuring were assessed. In addition, the effect of such structuring on contributions to total genetic diversity was assessed. Thirty-five Y-chromosome and 71 mtDNA haplotypes were identified. Most Y-chromosomes analysed (73.4%) were of zebu origin (11 haplotypes). Twenty-two Y-haplotypes (44 samples) belonged to the African taurine subfamily Y2a. All mtDNA haplotypes belonged to the "African" taurine T1 haplogroup with 16 samples and nine haplotypes belonging to a recently identified subhaplogroup (T1e). Median-joining networks showed that Y-chromosome phylogenies were highly reticulated with clear separation between zebu and taurine clusters. Mitochondrial haplotypes showed a clear star-like shape with small number of mutations separating haplotypes. Mitochondrial-based FST -statistics computed between cattle groups tended to be statistically non-significant (p > .05). Most FST values computed among groups and subpopulations using Y-chromosome markers were statistically significant. AMOVA confirmed that divergence between cattle groups was only significant for Y-chromosome markers (ΦCT  = 0.209). At the mitochondrial level, African sires resembled an undifferentiated population with individuals explaining 94.3% of the total variance. Whatever the markers considered, the highest contributions to total Nei's gene diversity and allelic richness were found in West African cattle. Genetic structuring had no effect on patterns of contributions to diversity.

Prevalence of Rift Valley fever in domestic ruminants in the central and northern regions of Burkina Faso.

The seroprevalence of Rift Valley fever was determined in cattle, sheep and goats in selected areas of northern and central Burkina Faso. A total of 520 serum samples were screened for anti-Rift Valley fever virus immunoglobulin G (IgG) antibodies using an inhibition enzyme-linked immunosorbent assay (ELISA). An average seroprevalence of 7.67% (range 5% to 20%) was found in ruminants in Seno and Soum provinces, and prevalences of 20% and 22.5% in cattle in Yatenga and Oubritenga provinces, respectively. The location, species and age of the animals were found to influence the seroprevalence. All the ELISA IgG-positive samples were tested for IgM in a competitive ELISA and were found negative, thus ruling out recent infections. The IgG-positive samples, including weak positives, were further tested in a serum neutralisation test for neutralising antibodies and 54.5% of these samples tested positive. The results show that the virus is in circulation in central and northern regions of Burkina Faso, suggesting the need for improved surveillance and control systems to prevent future outbreaks and the consequent economic impact of the disease in Burkina Faso livestock.

[Prevalence of tuberculosis and brucellosis in intra-urban and peri-urban dairy cattle farms in Ouagadougou, Burkina Faso]. / Prévalence de la tuberculose et de la brucellose dans les élevages bovins laitiers intra-urbains et périurbains de la ville d'Ouagadougou au Burkina Faso.

A study of the prevalence of bovine tuberculosis and brucellosis was conducted in dairy cattle farms in and around the city of Ouagadougou, Burkina Faso. It reveals the potential economic and health impact of these two major zoonoses in the study area. Three farming systems were included in the study. A total of 1,420 cattle were tested for tuberculosis and 1,689 cattle were tested for brucellosis. The intradermal tuberculin test was used for tuberculosis, and the buffered antigen test and indirect enzyme-linked immunosorbent assay were used for brucellosis. The overall prevalence rate is estimated to be 6.05% for tuberculosis and 3.61% for brucellosis. The prevalence rates of tuberculosis and brucellosis in urban and peri-urban dairy cattle farms in Ouagadougou were found to be high. As these two production-linked diseases are zoonotic, they could pose a major risk to human health and contribute significantly to reducing animal production and productivity in the areas covered by the study. Animals should be checked systematically prior to introducing them into dairy herds, with the ultimate goal of eradicating these two zoonoses.