The mayor of Hawaii County on Monday declared a state of emergency in response to Hawaii’s worst outbreak of dengue fever since the 1940s. Dengue fever, a virus transmitted through mosquitoes, comes as the state confronts concerns about the Zika virus, another mosquito-borne illness, after a baby was born infected with it last month.

Since September, there have been 250 reported cases of dengue fever in Hawaii, according to the Department of Health. The virus can cause high fever, intense headaches, joint pain and rashes on arms, but it is usually not fatal.

Hawaii County Mayor Billy Kenoi called the state of emergency for the Big Island, where two more cases of dengue fever were confirmed last week. He said the county will continue efforts to spray for mosquitoes. 



State representatives have urged Gov. David Ige to allocate more resources to preventing the disease, according to Honolulu news site Civil Beat. U.S. Rep. Tulsi Gabbard called for the governor last month to increase mosquito control and deploy the National Guard.

There have been only three other dengue fever outbreaks in the United States since 2001, according to the Centers for Disease Control and Prevention. One of those outbreaks was in Hawaii.