Screening of Filovirus Ribonucleic Acid in Humans, Wild Caught Non-Human Primates, Bats and Rodents in Laikipia North Sub-County, Kenya.
Auma, Ambala Peris
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In the recent decade, highly pathogenic human viruses have constantly emerged or re-emerged in different geographical locations worldwide approximately annually with the majority jumping from animals to humans. The major factors that have led to emergence of these viral diseases include urbanization, changes to local ecosystem and changes in human behaviours. Many of the emerging and re-emerging viruses are Ribonucleic acid (RNA) viruses with a high potential for re-assortment, recombination and mutation leading to new/different pathogenic viral strains. Despite the fact that non-human primates, bats and rodents have increasingly been implicated as potential sources of emerging zoonotic viral diseases, there is paucity of scientific data on Filoviruses circulating at the animal human interface in Laikipia North Sub-county, Kenya. The aim of this study was to detect and characterize filoviruses circulating in Laikipia, County Kenya. A cross sectional study design was adopted. Sampling technique employed in this study for human population was convenience sampling while for animal samples, capture release method using PREDICT 2 protocols was used. A total of 1092 samples of whole blood/blood swabs/blood clots (n=377), oral swabs (n=405) and rectal swabs/fecal (n=310) material were obtained from consenting individuals and the aforementioned animals. The samples were stored in TRizol® reagent (Thermo Fisher Scientific). The viral ribonucleic acid (RNA) was extracted. From the RNA, complimentary deoxyribonucleic acid (cDNA) was synthesized using Invitrogen superscript III first strand synthesis kit. The cDNA was amplified using PREDICT 2 filovirus universal primers in a consensus reverse transcriptase polymerase chain reaction (RT-PCR) targeting the Large (L) gene. In addition, immunoglobulin gamma enzyme linked immunosorbent assay (IgG ELISA) was conducted only on human and non-human primate serum samples. The IgG ELISA targeted IgG antibodies against Ebolaviruses and Marburg virus. Risk factors associated with zoonotic infections were assessed using surveys. All the samples tested negative for filoviruses using consensus RT-PCR and IgG ELISA. On risk factors analysis, bush meat was reported to be in circulation while less than 10% of the participants reported having interaction with wild animals in the last 6 months of the study. Despite the negative results in laboratory assays (consensus RT-PCR and IgG ELISA),cultural beliefs and practices, the circulation of bush meat and interaction of the community with wild life pre-disposes these population to the risk of contracting zoonotic viruses other than filoviruses. This study has identified potential risk factors associated with zoonotic disease transmission at the study area which are getting into contact with animals, sharing of water points with animals and use of untreated water for domestic use. These results suggest that circulation of filovirus was absent in humans, non-human primates, rodents and bats from Laikipia North Sub-county. Considering our findings, the study recommends continuous surveillance, systematic collection of samples from human population and animals for laboratory analysis for planning, implementation and evaluation of potential emerging filoviruses within the region and the use of both serological and molecular assays for detection of filoviruses.