BUCHAREST, Romania (AP) — Health authorities say mosquito-borne viruses have killed four people in Romania this week, bringing the total deaths from West Nile virus to 21.

The National Public Health Institute Friday reported 30 new cases of people getting sick after being bitten by mosquitoes carrying the virus. It said all the deaths involved people with other health complications.

The first deaths were recorded in August and the virus has made 200 people ill all over Romania.

The health ministry called on local authorities to take measures to prevent the spread of West Nile, adding the threat will decline as the weather gets cooler.

It also advised the public to take preventive measures such us using repellents, wearing long sleeves and covering windows with nets.

The virus is passed through bites from infected mosquitoes.