Abstract
Bats are natural reservoirs of Coronaviruses (CoV), which includes the genera
Alphacoronavirus (alphaCoV) and Betacoronavirus (betaCoV). Bat CoVs are also closely
related to human pathogens such as severe acute respiratory syndrome (SARS) and
the Middle East respiratory syndrome (MERS). Thailand has previously detected viruses
in the same lineage as SARS-CoV, in the Hipposiderous larvatus, and MERS-CoV from
unidentified bat guano. Thailand houses 139 different bat species, including
Tylonycteris spp., Pipistrellus spp. and Taphozous spp. These species have been
reported to carry MERS-CoV in other countries. It is thus important to conduct a study
to monitor these bat species and identify the viruses they harbor. Specimens from 645
bats, 33 species, were collected between 2011 and 2015, from 10 provinces (13
locations). Rectal swabs from these bats were analyzed using PCR, specifically for the
RNA-dependent RNA polymerase gene. Fifty seven (8.8%) of the samples were positive
for CoV; alphaCoV (19/57) and betaCoV (36/57). Two bats were found to be coinfected
with viruses of 2 different genera. Eight samples were positive for MERS-CoV
lineage, which is classified under betaCoV lineage C. Two of these samples were from
Tylonycteris robustula, the same bat species previously reported to harbor the virus in
China. Six samples were found in the Chaerephon plicata, which has never been
known to harbor CoV. Two samples from Rhinolophus malayanus were also positive
for SARS-CoV lineage, also previously reported in China from the same bat genus.
Detection of viruses in the same lineage of MERS-CoV and SARS-CoV in Thai bats
indicates the need for vigilant zoonotic disease surveillance to monitor virus jump
species to new hosts that may cause severe disease in humans or other animals, in
addition to the measures in place to contain disease outbreak. Thailand’s
preparedness and prompt diagnosis of the two imported (from Oman) MERS cases,
whose genetic analyses from whole genome sequencing revealed to be the same
strain as the outbreak in South Korea, prevented an outbreak in Thailand. Early
detection for cause of disease in patient and pre-identification of new pathogens from
natural reservoirs that can potentially case disease in humans can reduce the scale
and severity of next outbreak.
