No abstract

No abstract

To trace the evolution of highly pathogenic influenza A(H5N1) virus in West Africa, we sequenced genomes of 43 viruses collected during 2015 from poultry and wild birds in 5 countries. We found 2 co-circulating genetic groups within clade 2.3.2.1c. Mutations that may increase adaptation to mammals raise concern over possible risk for humans.

No abstract

Two serological tests for detection of antibodies to Ehrlichia (previously Cowdria) ruminantium, the causative agent of heartwater, were compared by using field sera collected from sheep and cattle as part of serosurveys in Ghana. Sera selected as either negative or positive by a new polyclonal competitive enzyme-linked immunosorbent assay (PC-ELISA) were tested by the indirect MAP1-B ELISA. Cutoff values of 14 percent positivity (14 PP) for both ruminant species were obtained for the MAP1-B ELISA by using preseroconversion Ghanaian sera and were compared with previously recommended cutoff values of 29 PP for sheep and 38 PP for cattle. With the 14-PP cutoff, of 151 sheep sera which tested negative by PC-ELISA, 89% were also negative by MAP1-B ELISA, while of 419 sheep sera positive by PC-ELISA, 98% were also positive by MAP1-B ELISA. Of 261 bovine sera negative by PC-ELISA, 82% were also negative by MAP1-B ELISA. Of 511 bovine sera positive by PC-ELISA, only 47% were positive by MAP1-B ELISA; these included 168 sera collected from cattle following first seroconversion as detected by both tests, with 125 of these sera positive by PC-ELISA but only 59 and 5 positive by MAP1-B ELISA with the 14-and 38-PP cutoff levels, respectively. These results indicate that both assays are highly sensitive and specific for detection of E. ruminantium exposure in sheep but that the MAP1-B ELISA lacks sensitivity for postseroconversion bovine sera in comparison to the PC-ELISA. Both tests confirm E. ruminantium seroprevalence of at least 70% in Ghanaian sheep; levels of exposure among Amblyomma variegatum-infested Ghanaian cattle are likely to be higher than the seroprevalence value of 66% obtained with the PC-ELISA.Heartwater, or cowdriosis, caused by the rickettsia Ehrlichia (previously Cowdria) ruminantium (10) and transmitted by ticks of the genus Amblyomma, is an often fatal disease of susceptible domestic ruminants in sub-Saharan Africa and some Caribbean islands (7). Epidemiological surveys of E. ruminantium prevalence in areas of endemicity have been limited by the lack of suitably sensitive and specific serodiagnostic tests (15). Fluorescent antibody tests based on E. ruminantiuminfected mouse macrophages (11), neutrophils and bovine endothelial cell cultures (27), and immunoblotting assays (20, 25) lacked specificity (12,16,25) and were too labor-intensive for mass screening. Several enzyme-linked immunosorbent assay (ELISA) systems have been developed over the last decade, with progressive improvement in performance. Indirect ELISA protocols using crude elementary body-derived antigen (26, 34) and a monoclonal antibody-based competitive ELISA (17) resulted in cross-reactions with other ovine and bovine Ehrlichia species (12,16