No Difference in the Prevalence of HIV-1 gag Cytotoxic T-Lymphocyte-Associated Escape Mutations in Viral Sequences from Early and Late Parts of the HIV-1 Subtype C Pandemic in Botswana.

HIV is known to accumulate escape mutations in the gag gene in response to the immune response from cytotoxic T lymphocytes (CTLs). These mutations can occur within an individual as well as at a population level. The population of Botswana exhibits a high prevalence of HLA*B57 and HLA*B58, which are associated with effective immune control of HIV. In this retrospective cross-sectional investigation, HIV-1 gag gene sequences were analyzed from recently infected participants across two time periods which were 10 years apart: the early time point (ETP) and late time point (LTP). The prevalence of CTL escape mutations was relatively similar between the two time points-ETP (10.6%) and LTP (9.7%). The P17 protein had the most mutations (9.4%) out of the 36 mutations that were identified. Three mutations (A83T, K18R, Y79H) in P17 and T190A in P24 were unique to the ETP sequences at a prevalence of 2.4%, 4.9%, 7.3%, and 5%, respectively. Mutations unique to the LTP sequences were all in the P24 protein, including T190V (3%), E177D (6%), R264K (3%), G248D (1%), and M228L (11%). Mutation K331R was statistically higher in the ETP (10%) compared to the LTP (1%) sequences (p < 0.01), while H219Q was higher in the LTP (21%) compared to the ETP (5%) (p < 0.01). Phylogenetically, the gag sequences clustered dependently on the time points. We observed a slower adaptation of HIV-1C to CTL immune pressure at a population level in Botswana. These insights into the genetic diversity and sequence clustering of HIV-1C can aid in the design of future vaccine strategies.

Near-complete genome of SARS-CoV-2 Delta variant of concern identified in a symptomatic dog (Canis lupus familiaris) in Botswana.

We sought to investigate whether SARS-CoV-2 was present, and to perform full-length genomic sequencing, in a 5-year-old male crossbreed dog from Gaborone, Botswana that presented overt clinical signs (flu-like symptoms, dry hacking cough and mild dyspnoea). It was only sampled a posteriori, because three adult owners were diagnosed with SARS-CoV-2 infection. Next-generation sequencing based on Oxford Nanopore Technology (ONT) was performed on amplicons that were generated using a reverse transcriptase real-time polymerase chain reaction (RT-qPCR) of confirmed positive SARS-CoV-2 nasopharyngeal and buccal swabs, as well as a bronchoalveolar lavage with mean real cycle threshold (qCt) value of 36 based on the Nucleocapsid (N) gene. Descriptive comparisons to known sequences in Botswana and internationally were made using mutation profiling analysis and phylogenetic inferences. Human samples were not available. A near-full length SARS-CoV-2 genome (∼90% coverage) was successfully genotyped and classified under clade 20 O and Pango-Lineage AY.43 (Pango v.4.0.6 PLEARN-v1.3; 2022-04-21), which is a sublineage of the Delta variant of concern (VOC) (formerly called B.1.617.2, first detected in India). We did not identify novel mutations that may be used to distinguish SARS-CoV-2 isolates from the dog and humans. In addition to Spike (S) region mutation profiling, we performed phylogenetic analysis including 30 Delta sequences publicly available reference also isolated from dogs. In addition, we performed another exploratory analysis to investigate the phylogenetic relatedness of sequence isolated from dog with those from humans in Botswana (n = 1303) as of 31 March 2022 and of same sublineage. Expectedly, the sequence formed a cluster with Delta sublineages - AY.43, AY.116 and B.1.617.2 - circulating in same time frame. This is the first documented report of human-associated SARS-CoV-2 infection in a dog in Botswana. Although the direction of transmission remains unknown, this study further affirms the need for monitoring pets during different COVID-19 waves for possible clinically relevant SARS-CoV-2 transmissions between species.