Publication
Porcine Deltacoronaviruses: Origin, Evolution, Cross-Species Transmission and Zoonotic Potential
Authors
Fanzhi Kong, Associate Professor, College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University
Qiuhong Wang, Professor, Center for Food Animal Health (CFAH), Department of Animal Sciences (ANSCI), and College of Veterinary Medicine
Scott P. Kenney, Associate Professor, CFAH, ANSCI, and College of Veterinary Medicine
Kwonil Jung, Research Scientist, CFAH, ANSCI, and College of Veterinary Medicine
Anastasia N. Vlasova, Associate Professor, CFAH, ANSCI, and College of Veterinary Medicine
Linda J. Saif, Distinguished University Professor, CFAH, ANSCI, and College of Veterinary Medicine
Quick Take
From swine flu to SARS, many devastating diseases have originated in animals and spread to infect humans. Scientists know that this process of interspecies transmission threatens public health whenever it occurs, so they carefully monitor how animal diseases evolve.
Swine, or pigs, are a particularly concerning pathway because they carry a wide variety of coronaviruses and frequently come in contact with humans. In fact, researchers have discovered an emerging pathogen called porcine deltacoronavirus (PDCoV) that they think could pose a risk of spreading to humans and poultry. In newborn piglets infected with PDCoV, the disease causes diarrhea, vomiting, and dehydration.
Understanding PDCoV could prevent a major threat to the swine industry and reveal mechanisms for how human coronaviruses emerge from animal sources. CFAES researchers reviewed the origin, evolution, cross-species transmission, and zoonotic potential of the disease and emphasize a need for further research.
Review Findings
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PDCoV was first detected in Hong Kong in 2012, but studies confirm it infected pigs in 2004 in China. Currently, PDCoV has been confirmed in most of East Asia, North America, and Southeast Asia. Further research can uncover whether PDCoV has spread to Europe, South America, Africa, or Australia.
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Deltacoronaviruses that infect pigs likely evolved from deltacoronaviruses infecting terrestrial birds. The nucleotides in all strains of PDCoV are very similar, which suggests that the differing strains are new.
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Coronaviruses have a high potential to change host species. The virus has infected a limited number of animals that aren’t pigs, and the virus genetics are all similar. This suggests the virus has not mutated and diversified much yet and is still adapting to new hosts.
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One study experimentally infected calves with PDCoV, although researchers do not know if they can be infected without human influence. Another study showed that young chickens and turkeys could contract the virus and pass it on to chicks. Wild, small carnivores in China have also contracted a nearly identical coronavirus.
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PDCoV was reported in the plasma of three Haitian children. The data shows at least two independent cases of PDCoV transmitting from pigs to humans. The virus has only caused asymptomatic or mild disease in humans, and researchers do not know if PDCoV can transmit from human to human.
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Although PDCoV causes milder illness than the similar porcine epidemic diarrhea virus (PEDV) and transmissible gastroenteritis virus (TGEV), PDCoV frequently infects pigs at the same time as other intestinal viruses. Co-infection may create more severe symptoms.
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Pig owners will need to monitor the health of their livestock and the handlers to ensure they can quickly detect future outbreaks. Researchers can conduct further studies to discover how far the disease has spread, how contagious it is between species, how it changes with co-infection, and how dangerous it is to humans.
Citation
Kong, F., Wang, Q., Kenney, S. P., Jung, K., Vlasova, A. N., & Saif, L. J. “Porcine Deltacoronaviruses: Origin, Evolution, Cross-Species Transmission and Zoonotic Potential.” Pathogens, January 2022, 11(1), 79. MDPI AG. http://dx.doi.org/10.3390/pathogens11010079