No abstract

Background There is limited understanding of SARS-CoV-2 pathogenesis in African populations with a high burden of infectious disease comorbidities such as HIV. The kinetics, magnitude and duration of virus-specific antibodies and the underlying B cell responses in people living with HIV (PLWH) in sub-Saharan Africa have not been fully characterized. Methods We longitudinally followed SARS-CoV-2 infected individuals in Durban, KwaZulu-Natal, South Africa and characterized SARS-CoV-2 receptor binding domain-specific IgM, IgG and IgA antibodies weekly for a month, and then at 3 months post diagnosis. 7/30 (41.7%) were PLWH, 83% (25/30) of which were on ART and with full HIV suppression. Potency of convalescent plasma neutralization was determined using a live virus neutralization assay and antibody secreting cell population frequencies were determined by flow cytometry. Results Similar seroconversion rates, time to peak antibody titer, peak magnitude and durability of anti-SARS-CoV-2 IgM, IgG, IgA, were observed in HIV uninfected and PLWH with complete HIV suppression on ART. In addition, similar neutralization potency against an isolate of SARS-CoV-2, circulating at the time of sampling in the first wave of SARS-CoV-2 infections in South Africa was observed in both groups. Loss of IgA was significantly associated with age (p=0.023) and a previous diagnosis of TB (p=0.018). Conclusions Similar antibody response kinetics and neutralization potency in HIV negative and PLWH on stable ART in an African setting suggests that COVID-19 natural infections may confer comparable antibody immunity in these groups. This provides hope that COVID-19 vaccines will be effective in PLWH on stable ART.

Equine encephalosis virus (EEV) is a neglected virus endemic to South Africa and is considered to generally result in mild disease in equines. Specimens were analyzed from live horses that presented with undefined neurological, febrile, or respiratory signs, or sudden and unexpected death. Between 2010 and 2017, 111 of 1523 (7.3%) horse samples tested positive for EEV using a nested real-time reverse transcriptase polymerase chain reaction (rRT-PCR). Clinical signs were reported in 106 (7.2%) EEV positive and 1360 negative horses and included pyrexia (77/106, 72.6%), icterus (20/106, 18.9%) and dyspnea (12/106, 11.3%). Neurological signs were inversely associated with EEV infection (OR < 1, p < 0.05) relative to EEV negative cases despite a high percentage of animals presenting with neurological abnormalities (51/106, 48.1%). Seventeen of the EEV positive horses also had coinfections with either West Nile (5/106, 4.7%), Middelburg (4/106, 3.8%) or African Horse sickness virus (8/106, 7.6%). To investigate a possible genetic link between EEV strains causing the observed clinical signs in horses, the full genomes of six isolates were compared to the reference strains. Based on the outer capsid protein (VP2), serotype 1 and 4 were identified as the predominant serotypes with widespread reassortment between the seven different serotypes.