This virus is becoming increasingly common as a cause of food-poisoning outbreaks. The tend over recent years is graphed below. In part of course, the rise will be due to increasing awareness of the organism over the period. A classical pointer to an outbreak mediated by SRSV or a similar virus is the proportion of people reporting vomiting alone. There is now little doubt that aerosolised vomit is a highly efficient means of transmission of virus, explaining why the disease spreads like wildfire in closed communities, even where hygiene standards are maintained.
Diagnosis is by demonstrating the virus by electron microscopy.
In principle liquid stool and vomit can both be submitted but the EM staff are not keen on vomit. A number of West African countries have reported an upsurge in cholera in 1996. Nigeria is worst affected with nearly 3000 cases in the first two months of 1996 while Niger and Senegal reported some hundreds over the same period. The outbreaks are not reason enough to cancel a planned trip. There are no special measures required because simple good sense dictates the following approach under all conditions - outbreak or not.