Potential For Zoonotic Emergence Of Coronavirus In Latin America

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Until SARS emerged in 2002 and began to burn its way through Chinese hospitals prior to spreading internationally (see SARS and Remembrance), only four coronaviruses (Alpha coronaviruses 229E and NL63, and Beta coronaviruses OC43 & HKU1) were known to infect humans, and they generally only produced mild illness.

Research has since shown that the SARS virus likely originated in bats and entered the human population - probably through contact with an intermediate host - before spreading widely in humans. 

Ten years later, a similar story began to emerge on the Arabian Peninsula, when another novel Coronavirus - MERS-CoV - began jumping from camels to humans.  This too, appears to be of bat-origin, making camels intermediate hosts.

While bats have long been known to be carriers of Rabies - and more recently linked to Nipah, Hendra, Ebola, Marburg viruses - over the past couple of decades it has become apparent that bats are also hosts for a wide variety of novel viruses with zoonotic potential.

In 2017 researchers from EcoHealth Alliance published a letter in Nature (Host and viral traits predict zoonotic spillover from mammals) providing the first comprehensive analysis of viruses known to infect mammals.

From their website summary: 

The study shows that bats carry a significantly higher proportion of viruses able to infect people than any other group of mammals; and it identifies the species and geographic regions on the planet with the highest number of yet-to-be discovered, or ‘missing’, viruses likely to infect people. This work provides a new way to predict where and how we should work to identify and pre-empt the next potential viral pandemic before it emerges.

When Steven Soderbergh made his pandemic thriller `Contagion’ a few years ago, technical adviser Professor Ian Lipkin created the fictional MEV-1 virus based on a mutated Nipah virus (see The Scientific Plausibility of `Contagion’) simply because of the very real possibility of someday seeing a bat-borne pandemic virus.

Some recent studies of coronaviruses in bats include:

EID Journal: A New Bat-HKU2–like Coronavirus in Swine, China, 2017

Emerg. Microbes & Infect.: Novel Coronaviruses In Least Horseshoe Bats In Southwestern China

PNAS: SARS-like WIV1-CoV Poised For Human Emergence

In 2016, Hotspots For Bat To Human Disease Transmission, we looked at a study that attempted to quantify the risks of zoonotic transmission of a wide variety of bat viruses.  While sub-Saharan Africa and Asia ranked highest, portions of South America showed considerable potential as well.

Credit University College London GB)

All of which brings us to an open-access editorial published SciELO - the Scientific Electronic Library Online - that examines the history of zoonotic jumps of coronaviruses - primarily from bats - and the potential for seeing that happen in South America.

Due to its length I've only included a few excerpts.  Follow the link to read it in its entirety.

Zoonotic emergence of coronavirus: a potential public risk for Latin America

Emergencia zoonótica de coronavirus: un potencial riesgo público para América Latina

Salim Mattar V 1 , Marco González T 1 *

1 Universidad de Córdoba, Facultad de Medicina Veterinaria y Zootecnia, Montería, Colombia

Coronaviruses (CoV) are a group of enveloped RNA viruses, single-stranded (positive sense) belonging to the order Nidovirales, family Coronaviridae. They are divided into four main groups: alpha, beta, gamma and delta; it seems, alpha and beta infect humans. The first known human coronaviruses (HCoV), HCoV-229E and HCoV-OC43, cause mild respiratory infections 1.

(SNIP)

The inter-species spread of coronaviruses in new hosts frequently occurs, SARS-CoV and MERS-CoV are the most notable examples of intra-species infection towards humans. The bovine, canine respiratory, dromedary and human OC43 coronaviruses potentially come from the same common ancestor, demonstrating the viral flexibility to adapt to new hosts. SARS-CoV probably originated in bats, whereas it is likely that PDCoV originated in birds. Therefore, the search for reservoirs in wild animals for CoV is of great interest 2.

The identification of SARS-CoV in Rhinolophid bats led to more intensive investigations of coronaviruses in humans and in bats. After the discovery of MERS-CoV as a zoonotic agent, coronavirus NL63 and HKU1 were recently detected as endemic in humans. Recent studies have shown that bat coronaviruses were the source of many human coronaviruses, including SARS-CoV, HCoV-229E and NL63 1.

(SNIP)

To demonstrate that bats harbor more CoV diversity than other host mammals, phylogenetic analyzes of the alpha and beta-coronavirus genera have been carried out, which were widely found in Chiroptera. The zoonotic origin of four of the six known human CoVs (HCV) has been demonstrated, three of which probably involved bats: SARS-CoV, MERS-CoV and HCoV-229E.

There are no studies on CoV of bats, nor in humans in Colombia and in Latin America are very insufficient. This critical lack of information in a country that holds the greatest diversity of Chiroptera in the region, reveals an ecoepidemiological gap that we have to overcome with the implementation of more studies aimed at better understanding the role of CoV in human health and animal in the region and in the world.

(Continue . . . )

In recent years we've seen a growing number of reports on bat viruses that pose confirmed or suspected zoonotic threats - including novel influenza viruses - making this an exciting time to be a Chiropterist.