There are still no signs that the West Nile virus (WNV) has established a foothold in Bulgaria, although concerns are growing.

A patient from the south-western Bulgarian town of Blagoevgrad near the Greek border was hospitalised late on August 11 at the Military Medical Academy in Sofia, suspected of being infected with the WNV.

According to media reports, the patient, a woman, is in a coma. She underwent a thorough medical examinations but so far there is no evidence to suggest that she has WNV.

Meanwhile, the virus has led to two deaths and 21 people confirmed to have been affected south of the border in Greece, Bulgarian news agency BTA said on August 12 2010.

Most cases have hit the central part of Greek Macedonia and other northern regions of the country

According to Greek daily Kathimerini, a total of 23 people have been admitted to hospitals since June 2010, all of them with brain inflammation and a form of meningitis. Of those, 21 have been confirmed as carriers of the West Nile virus. To date, two patients have died, one is in critical condition and another is serious but stable, the report said.

The West Nile virus (WNV) is a virus of the family Flaviviridae, found in both tropical and temperate regions. It mainly infects birds, but is known to infect humans, horses, dogs, cats, bats, chipmunks, skunks, squirrels, and domestic rabbits. The main route of human infection is through the bite of an infected mosquito. About 90 per cent of West Nile Virus infections in humans show no symptoms.

Authorities in northern Greece said they would step up mass spraying programmes in an attempt to ward off the mosquitoes.