What are coronaviruses?

Reposted from original blog, published on July 16, 2018

By Julie T. Shapiro, UFBI Fellow

You might not have heard of coronaviruses, but maybe you have heard of SARS (Severe Acute Respiratory Syndrome) and MERS (Middle East Respiratory Syndrome). These two diseases were both caused by coronaviruses that originated in animals and “spilled over” to people. SARS first broke out in China in 2002 – 2003^1–3, while MERS first broke out in Saudi Arabia in 2013^4,5. Although both diseases were contained, during both outbreaks there were fears of an even more serious global epidemic^6,7. Both had high rates of reported mortality: 9.6% for SARS⁸ and 35% for MERS⁹. In addition to SARS and MERS other coronaviruses can cause milder, cold-like infections in people ^10,11. The name “coronavirus” comes from the shape of the virus. Corona means crown in Latin and the shape of the virus makes it look like it has a crown or halo around it. You can see a picture in one of the early scientific articles on coronaviruses here.

Free-tailed bat (Chaerephon pumilus)

Coronaviruses are currently classified in four groups. The Alpha- and betacoronaviruses originate in bats, while the gamma- and deltacoronaviruses originate in birds¹². In bats, these viruses are found in the gastrointestinal tract, but they can also infect the respiratory tract of other organisms, including people¹². They do not appear to make the bats sick. Coronaviruses appear to switch hosts very easily¹⁶ and in addition to infecting people, have “jumped” over to many other species, including cats¹³, whales¹⁴, and pigs¹⁵.

As a UFBI Fellow, I am analyzing data on coronaviruses in the little free-tailed bat (Chaerephon pumilus) from Swaziland and the way anthropogenic disturbance might affect the prevalence and diversity of these viruses. The SARS epidemic, and the discovery of SARS-like coronaviruses in bats in China, spurred a lot of further research to discover new coronaviruses¹⁶ and many bats around the world appear to host them¹⁷. With every study, new coronaviruses are discovered. However, there are over 1100 species of bat¹⁸ and we have not yet studied coronaviruses in all of them. If we do not even know all the coronaviruses that are out there, we cannot understand why or how some of them spillover to people (or other animals). It is important to document as many coronaviruses as possible and then study how factors, such as anthropogenic disturbance, might affect both the diversity of different coronaviruses that bats host and the prevalence of these viruses. This information might help us predict and prevent future outbreaks of coronavirus disease.

References

1. Guan, Y. et al. Isolation and characterization of viruses related to the SARS coronavirus from animals in southern China. Science 302, 276–8 (2003).
2. Lee, N. et al. A major outbreak of Severe Acute Respiratory Syndrome in Hong Kong. N. Engl. J. Med. 348, 1986–1994 (2003).
3. Tsang, K. W. et al. A cluster of cases of Severe Acute Respiratory Syndrome in Hong Kong. N. Engl. J. Med. 348, 1977–1985 (2003).
4. Memish, Z. A. et al. Human infection with MERS coronavirus after exposure to infected camels, Saudi Arabia, 2013. Emerg. Infect. Dis. 20, 1012–1015 (2014).
5. Azhar, E. I. et al. Evidence for camel-to-human transmission of MERS coronavirus. N. Engl. J. Med. 370, 2499–2505 (2014).
6. Smith, R. D. Responding to global infectious disease outbreaks: Lessons from SARS on the role of risk perception, communication and management. Soc. Sci. Med. 63, 3113–3123 (2006).
7. Zumla, A. I. et al. Middle East respiratory syndrome coronavirus: epidemic potential or a storm in a teacup? Eur. Respir. J. 43, 1243–8 (2014).
8. Centers for Disease Control. SARS. (2017).
9. World Health Organization. Middle East respiratory syndrome coronavirus (MERS-CoV). (2018).
10. Vijgen, L. et al. Complete Genomic Sequence of Human Coronavirus OC43: Molecular Clock Analysis Suggests a Relatively Recent Zoonotic Coronavirus Transmission Event. J. Virol. 79, 1595–1604 (2005).
11. Vabret, A. et al. Detection of the new human coronavirus HKU1: A report of 6 cases. Clin. Infect. Dis. 42, 634–639 (2006).
12. Graham, R. L., Donaldson, E. F. & Baric, R. S. A decade after SARS : Strategies for controlling emerging coronaviruses. Nat. Rev. Microbiol. 11, 836–848 (2013).
13. Black, J. W. Recovery and in vitro cultivation of a coronavirus from laboratory-induced cases of feline infectious peritonitis (FIP). Vet. Med. Small Anim. Clin. 75, 811–4 (1980).
14. Mihindukulasuriya, K. A., Wu, G., St Leger, J., Nordhausen, R. W. & Wang, D. Identification of a novel coronavirus from a beluga whale by using a panviral microarray. J. Virol. 82, 5084–8 (2008).
15. Kocherhans, R., Bridgen, A., Ackermann, M. & Tobler, K. Completion of the porcine epidemic diarrhoea coronavirus (PEDV) genome sequence. Virus Genes 23, 137–144 (2001).
16. Woo, P. C. Y., Lau, S. K. P., Huang, Y. & Yuen, K.-Y. Coronavirus diversity, phylogeny and interspecies jumping. Exp. Biol. Med. 234, 1117–27 (2009).
17. Anthony, S. J. et al. Global patterns in coronavirus diversity. Virus Evol. 3, 1814–20 (2017).
18. Schipper, J. et al. The status of the world’s land and marine mammals: Diversity, threat and knowledge. Science (80-. ). 322, 225–230 (2008).