CROSS-SPECIES TRANSMISSION OF COVID-19 AT ANIMAL-HUMAN INTERFACE: A ONE
HEALTH APPROACH FOR IMPROVED DISEASE SURVEILLANCE AND CONTROL IN UGANDA
Abstract
Background: Reports of SARS-CoV-2 in animals have implicated
human sources. Similarities in SARS-CoV-2 cell receptors between humans
and animals suggest possible cross-transmission of COVID-19. Using a
One-Health approach, we assessed exposure to SARS-CoV-2 in humans with
no history of confirmed infection, selected domestic animals in their
homesteads, and in wild animals in Uganda. Methods: A
cross-sectional study was done in two districts where community COVID
cases were first reported: and at Uganda Wildlife Education Centre
(UWEC). Thirty-six humans and 48 domestic animals per district; and 14
animals at UWEC were sampled. Blood and nasopharyngeal or oropharyngeal
samples were analysed for SARS-CoV-2 antibodies, viral antigens, and
genome. Interviewer-administered questionnaire on socio-demographics,
travel history, disease symptoms and knowledge on COVID-19 was
conducted, data was analysed with STATA 16.0. Results: One
hundred forty participants were interviewed, 77% were below 49 years
old, 56% had only primary education, 50% were catholics; and 70%
subsistence farmers. COVID-19-related information was majorly from
radios (89%), families and or friends (55%). Over 60% were aware of
at least two COVID-19 symptoms. In humans, sero-prevalence was 31.9%,
4.2% and 13.9% for IgG, IgM, and COVID-19 antigen, respectively. IgG
sero-prevalence was significantly higher in females (47.2%) than males
(16.7%) with p=0.005, and similar trends were noted for IgM and
antigens. In domestic animals, caprine had the highest IgG
seropositivity, followed by bovine, avian and lastly canine at 70.6%,
50.0%, 42.9% and 38.5%, respectively. IgM was detected in one dog. At
UWEC, five animals had both IgG and IgM whereas two had only IgG. All
human and animal samples were RT-PCR negative. Conclusion: A
high sero-prevalence of IgG, indicates previous exposure. Ascertaining
cross-species transmission at human-animal interface was unproven due to
negative RT-PCR results, hence isolation and characterisation of virus
were not done.