By Shannon Knutsen and Charles C. Johnson
Two separate scientific studies have found that the deadliest form of Ebola virus, known as Zaire Ebola or ZEBOV, has the potential for foodborne transmission.
The first study was conducted in 2010 and jointly funded by Public Health Agency of Canada and the Canadian Food Inspection Agency. It was initiated after a reports that several pig farmers in the Philippines had become infected with the less virulent strain of Reston Ebola while tending to their livestock. To determine whether pigs could transmit the more lethal ZEBOV strain, Canadian researchers conducted a series of experiments. [Link: http://jid.oxfordjournals.org/content/204/2/200.long]
After injecting domestic pigs with the ZEBOV virus, scientists then introduced healthy pigs into the infected group. The study determined that infected pigs were able to transmit Zaire Ebola (ZEBOV) to healthy specimens via respiratory exposure. It also expressed concerns that a ZEBOV infection could be mistaken for other respiratory infections that are more commonly seen among domestic pigs and that infected pigs were capable of releasing large amounts of the lethal virus into the environment.
The findings were discussed in an editorial published by the Oxford University Journal of Infectious Diseases in 2011. While the article stressed that the study was cause for “consideration” and not panic, it acknowledged that scientists could not dismiss the possibility that Ebola could be a food-borne pathogen.
The editorial also expressed concerns about the effects of diseased pigs on food, medical and cosmetic products, as well as the potential for use of Ebola-infected pigs as a form of Bioterrorism.[Link: http://jid.oxfordjournals.org/content/early/2011/05/12/infdis.jir201.full.pdf]
In other data published in 2010, French researchers conducted a three year study of inhabitants of 220 villages in Gabon. Gabon has experienced several Ebola outbreaks since the mid 1990s. Although the origins of some of the outbreaks had been identified, others had not.
Scientists in the 2010 study looked at samples from 4300+ villagers. They found that a large number of inhabitants had ZEBOV antibodies despite the fact that there was no history of outbreak in their villages. The study attributed this immunity to the villagers exposure to fruit contaminated by the saliva of infected bats. [Link: http://www.ncbi.nlm.nih.gov/pubmed/21987749]
“The high frequency of ‘immune’ individuals with no disease or outbreak history raises questions as to the real pathogenicity of ZEBOV for humans in ‘natural’ conditions. Added to the lack of identifiable risk factors,
this points to bats as the main source of human exposure, through handling and ingestion of contaminated fruits.”
While neither scenario appears to pose an immediate threat to the United States, it’s important to remember that, despite assurances from officials in Washington, there is still quite a bit about the nature of Ebola that has yet to be disclosed.