Members of the genus Borrelia are arthropod-borne spirochetes that are human and animal pathogens. Vertebrate hosts, including wild animals, are pivotal to the circulation and maintenance of Borrelia spirochetes. However, information on Borrelia spirochetes in vertebrate hosts in Zambia is limited. Thus, we aimed to investigate the presence of Borrelia spirochetes in wild animals and cattle in Zambia. A total of 140 wild animals of four species and 488 cattle DNA samples from /near the Kafue National Park were collected for real-time PCR screening, followed by characterization using three different genes with positive samples. Five impalas and 20 cattle tested positive using real-time PCR, and sequence analysis revealed that the detected Borrelia were identified to be Borrelia theileri, a causative agent of bovine borreliosis. This is the first evidence of Borrelia theileri in African wildlife and cattle in Zambia. Our results suggest that clinical differentiation between bovine borreliosis and other bovine diseases endemic in Zambia is required for better treatment and control measures. As this study only included wild and domestic animals in the Kafue ecosystem, further investigations in other areas and with more wildlife and livestock species are needed to clarify a comprehensive epidemiological status of Borrelia theileri in Zambia.

Highly pathogenic avian influenza viruses (HPAIVs) with H5 and H7 hemagglutinin (HA) subtypes are derived from their low pathogenic counterparts following the acquisition of multiple basic amino acids in their HA cleavage site. It has been suggested that consecutive adenine residues and a stem-loop structure in the viral RNA region that encodes the cleavage site are essential for the acquisition of the polybasic cleavage site. By using a reporter assay to detect non-templated nucleotide insertions, we found that insertions more frequently occurred in the RNA region (29 nucleotide-length) encoding the cleavage site of an H5 HA gene that was predicted to have a stem-loop structure containing consecutive adenines than in a mutated corresponding RNA region that had a disrupted loop structure with fewer adenines. In virus particles generated by using reverse genetics, nucleotide insertions that created additional codons for basic amino acids were found in the RNA region encoding the cleavage site of an H5 HA gene but not in the mutated RNA region. We confirmed the presence of virus clones with the ability to replicate without trypsin in a plaque assay and to cause lethal infection in chicks. These results demonstrate that the stem-loop structure containing consecutive adenines in HA genes is a key molecular determinant for the emergence of H5 HPAIVs.

Background: We revised the taxonomy and identification of the species of the genus Bothriocroton in light of entire mitochondrial genomes and nuclear rRNA genes, scanning electron microscopy, and light microscopy. Methods: (i) phylogenetic trees inferred from entire mitochondrial genomes and nuclear rRNA genes, (ii) species delimitation analyses (ABGD and bPTP), and (iii) the study of morphology by scanning electron microscopy (SEM) and light microscopy. Results: The most complete picture of the Bothriocroton ticks so far. Thirty-five new mitochondrial genomes and 27 partial 18S–28S rDNA sequences were generated. Phylogenetic analyses recovered seven well-supported clades corresponding to species-level lineages. Intraspecific genetic divergence ranged from 0.14 to 1.16%, whereas interspecific divergence ranged from 4.94 to 21.75%. Three new species were described, and the morphological diagnosis of other species was improved by redescribing two other species. In addition, we updated and improved the morphological dichotomous keys to male and female ticks. Conclusions and prospects: The routine genotyping of Bothriocroton ticks to identify species and to confirm provisional identifications of species from their morphology is an alternative to the morphological identification of closely related Bothriocroton ticks.