Alphacoronavirus
Alphacoronavirus is one of the four genera within the Coronaviridae family, which are enveloped viruses characterized by their rounded shape and prominent surface projections. This genus, along with betacoronaviruses, primarily infects mammals, including humans, while gammacoronaviruses and deltacoronaviruses are more commonly associated with birds. Alphacoronaviruses have been present since ancient times, with their origins traced back to around 2400 BCE.
Notable species within this genus include HCoV-229E and HCoV-NL63, both of which can cause the common cold in humans, typically resulting in mild illness but potentially leading to more severe respiratory infections in certain cases. In addition to humans, alphacoronaviruses also affect domestic animals; for example, they can cause significant diseases in swine such as porcine epidemic diarrhea virus (PEDV) and transmissible gastroenteritis (TGE), which can be particularly deadly to young piglets. Furthermore, dogs and cats can be infected by alphacoronaviruses, leading to conditions like canine coronavirus disease and feline infectious peritonitis. Researchers continue to study these viruses, especially in the context of zoonotic potential, as animal coronaviruses could pose risks to human health.
On this Page
Alphacoronavirus
Alphacoronavirus is one of four genera of coronaviruses, which belong to the family Coronaviridae. Alphacoronavirus species are enveloped viruses, which means they are wrapped in an outer coating. Coronaviruses are round and have large projections that come out of their surfaces. The other genera are betacoronavirus, gammacoronavirus, and deltacoronavirus. Coronaviruses often cause respiratory and enteric illnesses, though some cause disease in other organ systems. Scientists believe the first coronaviruses developed in roughly 8000 BCE, and the first alphacoronaviruses developed in roughly 2400 BCE.
Overview
Scientists differentiate alphacoronavirus, betacoronavirus, gammacoronavirus, and deltacoronavirus species based on serology exams and phylogenetic clustering. The different genera infect different types of animals. Alphacoronavirus and betacoronavirus species infect only mammals, including humans. Gammacoronavirus and deltacoronavirus species are more likely to infect birds. Alphacoronavirus and betacoronavirus species have some similarities, and scientists have studied these genera in animals in the hopes of identifying potential zoonotic diseases before they can cause outbreaks among human populations.
Alphacoronavirus and betacoronavirus species are common in bats. Rh-BatCoV-HKU2, Mi-BatCoV 1A, Mi-BatCoV 1B, Mi-BatCoV-HKU8, and Sc-BatCoV-512 are all alphacoronavirus species that scientists have identified in bat populations. Scientists study these diseases because they want to learn more about diseases and because scientists realize that coronaviruses that live in animals could eventually infect humans.
Scientists have identified numerous alphacoronavirus species. Two species of the alphacoronavirus, HCoV-229E and HCoV-NL63, can cause the common cold in humans. (Other types of viruses can also cause the common cold.) Scientists first identified these alphacoronavirus species in the 1960s. These viruses do not generally cause serious illness in humans, but they can sometimes cause serious illness if they result in a lower-respiratory infection.
Several alphacoronavirus species also infect swine. Porcine epidemic diarrhea virus (PEDV) and transmissible gastroenteritis (TGE) are both acute illnesses that occur in swine. Both are enteric illnesses that spread easily. PEDV and TGE can be deadly to swine, but younger piglets are most susceptible to the disease. Sometimes TGE can be endemic in populations, and sometimes the disease can be introduced and cause a one-time outbreak. These diseases can be costly for farmers raising swine. Porcine respiratory coronavirus (PRCV) is another disease in swine caused by an alphacoronavirus species.
Particular alphacoronavirus species can also infect dogs and cats. Canine coronavirus disease (CCoV) is an intestinal disease caused by an alphacoronavirus. The disease can be more severe in young dogs, and an infected dog may remain contagious for up to six months. Feline infectious peritonitis (FIP) is a disease caused by the feline coronavirus, which is also an alphacoronavirus. The disease usually affects the gastrointestinal tract, and in those cases, it is called feline enteric coronavirus (FeCV). The disease is generally not life-threatening. However, sometimes the virus can change its behavior and infect a cat’s white blood cells. When this happens, it is called feline infectious peritonitis virus (FIPV), and it is often fatal for cats.
Bibliography
August, Tom A., Fiona Mathews, and Miles A. Nunn. “Alphacoronavirus Detected in Bats in the United Kingdom.” Vector-Borne and Zoonotic Diseases, vol. 12, no. 6, 2012.
“Coronavirus: Detailed Taxonomy.” AVMA, 2020, www.avma.org/sites/default/files/2020-02/AVMA-Detailed-Coronoavirus-Taxonomy-2020-02-03.pdf. Accessed 15 Oct. 2021.
Cui, Jie, Fang Li, and Zheng-Li Shi. “Origin and Evolution of Pathogenic Coronaviruses.” Nature Reviews Microbiology, vol. 17, 2019, pp. 181–92
“Human Coronavirus Types.” CDC, 15 Feb. 2020, www.cdc.gov/coronavirus/types.html. Accessed 27 Mar. 2023.
Laguipo, Angela Betsaida B. “What Are Coronaviruses?” Medical Life Science News, 24 Mar. 2021, www.news-medical.net/health/What-are-Coronaviruses.aspx. Accessed 27 Mar. 2023.
Shors, Teri. “Coronavirus.” Access Science, January 2021, www.accessscience.com/content/coronavirus/163220. Accessed 15 Oct. 2021.
Tyrrell, D. A. J. and M. L. Bynoe. “Cultivation of a Novel Type of Common-cold Virus in Organ Cultures.” British Medical Journal, vol. 1, no. 5448, 1965, pp. 1467–70.
Zhu, Zhixing, et al. “From SARS and MERS to COVID-19: A Brief Summary and Comparison of Severe Acute Respiratory Infections Caused by Three Highly Pathogenic Human Coronaviruses.” Respiratory Research, vol. 21, no. 224, 2020.