Abstract/Summary
The severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2),
etiological agent of the novel coronavirus disease 2019 (COVID-19), has
spread since December 2019, resulting in massive health and economic
crisis worldwide. While efforts to stop the pandemic are crucial,
collecting epidemiological data to help manage current and future
pandemics will be important.
In addition to humans, serological and molecular based studies have
demonstrated SARS CoV-2 exposure in several wild, domestic and farmed
animals. For examples Shriner and the team showed serologically an
exposure of 40% to the white deer living in close proximity to urban
centers. Additional reports have also emerged of susceptibility of
animal’s species like cats, ferrets, raccoon dogs, cynomolgus macaques,
rhesus macaques, white-tailed deer, rabbits, Egyptian fruit bats, and
Syrian hamsters to SARS-CoV-2 infection.. It’s worth emphasizing that
these reports are based on experimental data mostly derived from Europe,
USA, South America and parts of Asia. In limited instances natural
infections of SARS-CoV-2 have been reported in pet dogs, cats, tigers,
lions, snow leopards, pumas, gorillas at zoos and farmed mink and
ferrets. The presence of the virus in animal species and an
understanding of whether these are natural or recent human to animal
transmissions is important. It’s possible that such transmission could
passage the virus or subject the virus to a different immunological
pressure thereby helping with the development of viral variants in
addition to being a host for future reservoirs of the virus.
In Kenya SARS-CoV-2 was first detected on March 12th2020 from imported human cases of persons who had travelled from the
United States. This was followed by detection of imported cases majorly
from China, Sweden and United Kingdom. Later infections were confirmed
in Nairobi and Mombasa suggesting further cases of disease importations
through the major ports of entry. However, no comparable data on animal
exposure have hitherto been generated in Kenya. To address this key
concern, we focused on three objectives; 1) development of a robust
antibody ELISA based on crude SARS-CoV-2 lysate. 2) SARS-CoV-2 serology
of domestic animals in Kenya. 3) Corroboration of the crude lysate based
seroprevalence data and a commercial ELISA kit based on the Spike
receptor binding domain (RBD) antigen.
Our sample set included camel sera (both pre- & post outbreak sera), as
well as sera from cats and dogs collected at the peak of the pandemic.
Our results using the ELISA based on crude SARS-CoV-2 lysate indicated
SARS-CoV-2 antibodies in camels (71%, N=145), cats 11% (N=16) and dogs
(81%, N=36) with varying titer levels. These findings were comparable
to those obtained using the commercial ELISA kit based on the spike RBD
antigens.
In summary, the data warrants two key conclusions: (i) we have
demonstrated that the crude lysate ELISA allows for SARS-CoV-2 antibody
detection, and given its potential to offer robust detection could be
applied for initial mass screening (ii) although the current study
cannot disentangle the relative contributions of antigenic
cross-reactivity, pre-pandemic exposure to SARS-CoV-2 or human-animal
transmission, it nonetheless demonstrates for the first time the
prevalence of SARS-CoV-2 like antibodies in domestic and wild animals in
Kenya. Our findings set the scene for further research into the
prevalence of SARS-CoV-2 in domestic and wild animals to understand
their potential epidemiological implications.