Times of India
15 April 2010
London, India

French Experts Find Evidence Of Pepper Virus Infecting People
It has always been assumed that plant viruses cannot infect animals, and vice versa. But French scientists have now found what they claim is the first evidence of a plant virus infecting humans — they say pepper virus is making people sick.

A team at the University of the Mediterranean in Marseilles, France, led by Didier Raoult, have found RNA from the pepper mild mottle virus in the faeces of 7% of the 304 adults they tested; those with the virus were more likely to report fever, itching and abdominal pain, the ‘New Scientist’ reported on Wednesday.

Not everyone is convinced, however. Because Raoult looked at many possible symptoms, he would be expected to find a few that randomly appear more common in viruspositive people, according to Robert Garry, a virologist at Tulane University in New Orleans, Louisiana.

Moreover, in order to enter a cell and replicate, a virus must bind to a receptor on its surface, and a plant virus would be highly unlikely to recognise a receptor on a human cell, Garry said.

One possibility, Raoult said, is that the virus does not infect human cells directly. Instead, the naked viral RNA may alter the function of the cells via a mechanism similar to RNA interference, in which presence of certain RNA sequences can turn genes on and off.

The study identified a local source of Pepper mild mottle virus (PMMoV), a plant virus, and linked the presence of PMMoV RNA in stool with a specific immune response and clinical symptoms. Although clinical symptoms may be imputable to another cofactor, including spicy food, their data suggest the possibility of a direct or indirect pathogenic role of plant viruses in humans.

PMMoV RNA sequences were recovered from twelve (57%) of the twenty-one pepper or spice-containing food products picked for the research. Of all Tabasco sauce contained the highest viral load.

The French team is now working to gather more direct evidence that the virus does infect humans. The findings have been published in the PLoS One journal.

Unpalatable?

• RNA from the pepper mild mottle virus found in faeces of 7% of the 304 adults tested by a team of experts
• Those with the virus are more likely to report fever, itching and abdominal pain
• The virus does not infect human cells directly. Instead, the naked viral RNA may alter cell function via a mechanism similar to RNA interference, in which presence of certain RNA sequences can turn genes on and off
• Pepper virus RNA sequences found from 12 (57%) of the 21 pepper or spice-containing food products picked for the study. Of all Tabasco sauce had the highest viral load