The first human infections of a novel coronavirus were identified in late of
2012. The coronavirus was later named hCoV-EMC based on genetic analysis at the
Erasmus Medical Center [1].
More
recently, the World Health Organization (WHO) has adopted the label MERS-CoV
for hCoV-EMC [2].
As noted in a previous post, at least 50+ MERS cases have been reported
from eight countries; France, Jordan, Italy,
Kingdom of Saudi Arabia, Qatar, Tunisia, United Arab Emirates, and the United
Kingdom.
The nature of the transmission is uncertain, but some of these infections are
occurring in hospital settings; several health care workers have been infected.
Four of these clusters, one from France,
one from Italy, one from Tunisia, and one from the United Kingdom, occurred
outside of the Middle East region. The index cases in all four of these
clusters had previously visited countries within the Arabian Peninsula. The
index cases of other clusters, as well as other individual isolated cases, were
all apparently infected in the geographic area of the Arabian Peninsula. These data suggest that the animal host for MERS-CoV
is endemic on the Arabian Peninsula.
MERS-CoV is one of
six known coronaviruses that infect humans [3]. The most well-known of these six
is SARS-CoV. SARS-CoV infected more than 8000 people from
2002-2003. Although SARS-CoV was initial identified in palm civets, later
research indicated that the Chinese horseshoe bat (Rhinolophus sinicus)
was the most likely host organism with the civets acting as an intermediate
amplification host [4]. The Chinese
horseshoe bat (Rhinolophus sinicus) is one of approximately 77 bat
species included in a single genus of Rhinolophus in the family RHINOLOPHIDAE.
The Erasmus Medical Center researchers that initially
identified hCoV-EMC (MERS-CoV) in 2012 noted that this novel coronavirus was
most closely related to two coronaviruses found in vesper and pipistrelle bats
(family VESPERTILIONIDAE). The researchers indicate that the closest match of
hCoV-EMC is the coronavirus BtCoV-HKU5 from Japanese house bats (Pipistrellus
abramus) [5].
The authors comment that “it is tempting to speculate that
HCoV-EMC/2012 emerged from bats—either directly or via an intermediate animal
host, possibly Pipistrellus bats. This bat species is known to be
present in the Kingdom of Saudi Arabia and neighboring countries.” [6]
The
identification of the Chinese horseshoe bat (Rhinolophus sinicus) as a
host reservoir for SARS-CoV and the discovery by the Erasmus Medical Center
Team that MERS-CoV is related to coronaviruses found in the VESPERTILIONIDAE bat
family provides a basis for considering bats as the host organism for MERS-CoV in the Arabian Peninsula.
Because Saudi Arabia has reported the most MERS cases, and because it
occupies a great percentage of the Arabian Peninsula, bat species in Saudi
Arabia should be evaluated as potential hosts for this novel coronavirus. More
than 30 species of bats have been identified in a 2003 report on the bats of
Saudi Arabia by Abdulaziz Al-Agaili and Wikipedia [7]. A
review of the geographic distribution of these species on the Arabian
Peninsula, in comparison with bat species from Qatar, United Arab Emirates [8],
and Jordan [9] where other MERS cases
have been reported, suggests that four species from three families,
HIPPOSIDERIDAE, RHINOLOPHIDAE, and VESPERTILIONIDAE, should be considered as
possible MES-CoV reservoirs in the region.
Four bat species, Asellia tridens, Otonycteris
hemprichii, Pipistrellus kuhlii, and Rhinolophus clivosus have
a sufficiently large geographic distribution on the Arabian Peninsula to
be reservoir species of MERS-CoV. All of these species are from the sub order of
Microchiroptera. These small bats are generally insectivorous but some
leaf-nose bats in this suborder are known to eat fruit [10]. Pipistrellus
arabicus and Pipistrellus ariel are not included in the potential
list of hosts because of their limited geographic distribution on the Arabian Peninsula.
Fruit eating bats, members of the sub order Megachiroptera, are known to be
reservoir for diseases such as Ebola and Marburg hemorrhagic fever. The only
fruit bats that are sporadically reported from the region are
Rousettus aegyptiacus and
Eidolon helvu, but they are not found in the eastern portion of the
peninsula where many of the MERS cases have been reported. While fruit eating
bats could be a reservoir, the other four Microchiroptera species are more
likely candidates.
While a microbat
species in the region may be the host reservoir, the possibility of
intermediate hosts associated with date farming and consumption should not be
discounted in the transmission of MERS-CoV.
Species Distribution Information
Asellia tridens
http://www.iucnredlist.org/details/2154/0
Otonycteris hemprichii
http://www.iucnredlist.org/details/15663/0
Pipistrellus kuhlii
http://www.iucnredlist.org/details/17314/0
Rhinolophus clivosus
http://www.iucnredlist.org/details/19531/0
References
[10] http://en.wikipedia.org/wiki/Microbat
