Masters Degrees (Medical Virology)

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Browsing Masters Degrees (Medical Virology) by Author "Kotze, Andrea"

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    Investigating the host range of Neoromicia capensis coronavirus in vitro
    (2019-04) Kotze, Andrea; Preiser, Wolfgang; Suliman, Tasnim; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Pathology. Medical Virology.
    ENGLISH ABSTRACT: Coronaviruses are known to cause disease in humans and animals. Two important human coronaviruses that have caused epidemics are severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV). These coronaviruses originated in animals and were introduced into the human population through zoonotic transmission. Neoromicia capensis coronavirus (NeoCoV), a bat coronavirus that was discovered in the South African bat species Neoromicia capensis, is 85.5% genetically identical to MERS-CoV. It is believed that NeoCoV is an ancestor of MERS-CoV; however, the potential for NeoCoV to emerge as a potential zoonotic agent has not yet been investigated. This study investigated the host range of NeoCoV in order to assess its potential to cross the species barrier from bats to other mammals. This study attempted to isolate NeoCoV in cell culture to investigate its behaviour in vitro. The host range of NeoCoV was further explored by developing viral pseudoparticles that expressed the spike proteins of NeoCoV, MERS-CoV or SARS-CoV. These pseudoparticles were used to infect various cell lines of mammalian origin to determine which animal species NeoCoV may be able to infect and if its host range has any similarities to that of MERS- and/or SARS-CoV. Attempts were made to isolate NeoCoV in cell culture by inoculating host-derived cells with NeoCoV-positive bat faecal homogenate. Attempts were proven unsuccessful by a highly sensitive quantitative reverse transcription polymerase chain reaction assay. Infecting cell lines with pseudoparticles bearing either the NeoCoV, MERS- or SARS-CoV spike protein revealed that NeoCoV could possibly utilise N. capensis kidney cells for replication, and not the lungs or trachea. Infection of Pipistrellus pipistrellus kidney cells with the three different pseudotypes yielded low levels of infection, suggesting that this cell line is less susceptible to infection by the three viruses. None of the pseudotypes generated were able to infect a kidney cell line derived from Camelus dromedarius, a known host of MERS-CoV, indicating that camel kidney cells are likely not the site of MERS-CoV replication. Results from pseudoparticle infection experiments suggest that NeoCoV would have the ability to infect Vero cells, which originate from African green monkey kidneys, with the same efficiency as MERS- and SARS-CoV. Since pseudoparticles bearing the spike protein of NeoCoV have the ability to infect Vero cells, NeoCoV might have the ability to cross the species barrier from its natural host to non-human primates such as Cercopithecus aethiops. As the human population encroaches on wildlife habitats, the transmission of viruses capable of crossing the species barrier becomes an increasing risk to public health.