Canadian researchers have shown that a species of Ebola virus from Zaire, which is extremely virulent in humans, can replicate in pigs, trigger the disease, and be transmitted to animals that had not previously been exposed to the virus. The results of this work have been published in The Journal of Infectious Diseases.
To prevent human outbreaks of Ebola hemorrhagic fever, it is important to identify the species of animals that replicate and transmit the virus to other animals and, potentially, to people.
The Ebola virus of Zaire, one of the multiple species of this virus, has a 90% mortality rate in humans Antibodies have been found for other species not associated with the human disease, known as Ebola Reston virus, in pig farms in the Philippines, suggesting that pigs may be able to transmit virulent Ebola virus to people as well.
This study, led by Gary P. Kobinger, of the Public Health Agency of Canada, and Hana Weingartl, of the National Center for Foreign Animal Disease of the Canadian Food Inspection Agency, investigated whether Zabo's Ebola virus, such as the Ebola Reston virus, could replicate and cause disease in pigs and be transmitted to other animals. Thus, using farm pigs, the researchers evaluated the replication of the virus and its pathogenicity and elimination.
By eliminating the virus from the nasal mucosa, the infected pigs transmit the infection to the animals with which they live
The researchers found that after the mucosa was exposed to the Ebola virus of Zaire, the pigs replicated the virus in large quantities, especially in the respiratory tract. The elimination of the virus from the nasal mucosa was detected for up to 14 days after infection, and a severe lung disease. The study also showed that the virus was transmitted to all pigs that were previously not exposed and that lived with the infected animals.
The authors of the study suggest that farm pigs are susceptible to the Èbola virus of Zaire through mucosal infection, and that the severe respiratory disease that accompanies it is associated with the elimination of high viral loads in the environment, exposing pigs without infect this infection.
In contrast to the systemic syndrome that affects various organs, which often leads to shock and death in primates, these researchers emphasize, the respiratory syndrome that pigs develop can be confused with other porcine respiratory diseases.