All things considered, the past couple of decades have turned out to be busy ones for Chiroptologists (scientists who study bats). Increasingly these winged mammals are being viewed as naturals hosts for, and potential vectors of, a number of newly recognized emerging infectious diseases.
Long known for carrying rabies, over the past 20 years scientists have discovered that bats can also harbor such viral nasties as Marburg, Ebola, Nipah, Hendra, and a variety of coronaviruses (including SARS).
Quite surprisingly, in March of 2012, we also learned of a new H17 flu subtype – the first ever known to infect bats (see A New Flu Comes Up To Bat).
Last week’s discovery a of match to a segment of the MERS-CoV in a bat sample (see EID Journal: Detection Of MERS-CoV In Saudi Arabian Bat, once again points towards bats as being the likely animal host for an important emerging virus.
Yesterday the CDC’s EID Journal published a letter from researchers who sampled bats in Mexico and Brazil, and like similar studies in Europe, Africa, and Asia (see EID Journal: EMC/2012–related Coronaviruses in Bats, Coronavirus `Closely Related’ To HK Bat Strains), they found a number novel coronaviruses among them.
While none were matches for either SARS or MER-CoV, notably one was a Betacoronavirus – as are MERS and SARS. I’ve provided some excerpts below, but follow the link to read it in its entirety.
Luiz Gustavo Bentim Góes1, Sicilene Gonzalez Ruvalcaba1, Angélica Almeida Campos, Luzia Helena Queiroz, Cristiano de Carvalho, José Antonio Jerez, Edison Luiz Durigon, Luis Ignacio Iñiguez Dávalos, and Samuel R. Dominguez
To the Editor: Bats are now recognized as natural reservoirs for many families of viruses that can cross species barriers and cause emerging diseases of humans and animals. Protecting humans against emerging diseases relies on identifying natural reservoirs for such viruses and surveillance for host-jumping events.
The emergence of the Middle East respiratory syndrome coronavirus (MERS-CoV) on the Arabian Peninsula (1) further justifies increased surveillance for coronaviruses (CoVs) in bats. MERS-CoV most likely is a zoonotic virus from a bat reservoir and is associated with high case-fatality rates among humans.
The existence of a diverse array of alphacoronaviruses in bats in the United States, Canada, and Trinidad has been reported (2–6). Recently, a possible new alphacoronavirus was detected in an urban roost of bats in southern Brazil (7), and a survey of bats in southern Mexico reported 8 novel alphacoronaviruses and 4 novel betacoronaviruses, 1 with 96% similarity to MERS-CoV (8). These findings expand the diversity and range of known bat coronaviruses and increase the known reservoir for potential emerging zoonotic CoVs.
In summary, we found a novel alphacoronavirus in bats from Brazil and a novel betacoronavirus in a bat from Mexico. Both viruses were detected in bats with known or potential contact with humans. Because the bats we sampled were mostly adult males, the prevalence of CoVs that we identified is probably an underestimation of the true incidence of CoVs in these bat populations.
For bats of other species, incidence of CoVs among juvenile and female bats is higher (2,9). Furthermore, we used a non-nested, broadly conserved CoV PCR, which might have limited the sensitivity of CoV RNA detection.
The finding of a novel betacoronavirus in insectivorous bats in the New World is noteworthy. Three human CoVs (229E, SARS-CoV, and MERS-CoV) all have animal reservoirs of closely related viruses in Old World insectivorous bats (10) from which they most likely emerged, either directly or indirectly, into the human population.
Ongoing surveillance for CoVs in wildlife and increased research efforts to better understand the factors associated with CoV host-switching events are warranted.
None of this is meant to demonize bats, as they play an important role in our ecosystem. However, bats are increasingly being associated with diseases deadly to humans.
To learn how you can stay safe when bats are near, the CDC offers the following advice.