Wash your hands!
THEY'RE lurking in huge armies, plotting to take you down at the first opportunity, and all you have to do to give them that opportunity is to pick your teeth.
They're microscopic beasties that live on your hands and can cause serious illnesses.
But while they can easily be annihilated by proper handwashing, many people don't bother to, and that's got Sean Gibney of North Coast Public Health Unit worried.
So much so that following reports of people going to hospitals with infections caused by enteroviruses, he wants to remind the community to practice good personal hygiene in the home and workplace.
"These viruses are quite common yet they can result in a range of illnesses, some of them quite severe," Mr Gibney said.
"Enteroviruses may cause at least 10 distinct illnesses, most of which are mild and of short duration but some can be very serious."
Mr Gibney added the viruses are commonly spread by the faecal-oral route (contamination of hands or objects by human waste) and are capable of attacking many different organs of the body.
"They can produce a range of symptoms, including flu-like illness with fever, headache, nausea and vomiting," he said.
"A fairly common and occasionally serious illness is viral meningitis (inflammation of the covering of the brain) with symptoms of headache, fever, photophobia (avoidance of bright lights), drowsiness, muscle pain and sometimes a rash.
"While most people with viral meningitis will recover completely within a week or two, it may progress to very severe illness that requires specialised medical treatment. So anyone experiencing these symptoms should seek medical attention immediately."
Mr Gibney said the best means of avoiding transmission of these viruses is good personal hygiene, particularly good hand-washing.
"People should wash their hands before they eat or handle food, after working or playing, after blowing their nose, after going to the toilet, and after touching their pets," he said.