Aedes aegypti mosquitoes known to transmit diseases such as dengue fever and yellow fever have been detected in California. The mosquito that prefers to bite humans over animals were first spotted in the Central Valley in June, in San Mateo in August, and this week in Fresno. Authorities are exerting all efforts to control the spread of the mosquitoes and continue to monitor possible cases.
According to health officials, Aedes aegypti bites humans any time of the day, not just at night as earlier thought. They also spread quickly as they just need a very small amount of water where they can lay their eggs. Any stagnant water can be the breeding ground of these aggressive mosquitoes. The Aedes aegypti appears to be dark with white bands and markings on its legs.
"If it gets away it will change the way we live in California. You may not be able to sit on your patio and enjoy a cup of coffee during the day without getting bit. The nightmare scenarios is it gets established in California and then a mosquito bites someone with an imported case of dengue," said Tim Phillips of the Mosquito and Vector Control in Fresno in an interview with San Francisco Gate.
There are different theories how the dengue and yellow fever-carrying mosquitoes reached California. One possibility is that they may have entered the state as eggs coming with shipment containers from other countries.
Authorities are reaching out to medical experts to be aware of the presence of Aedes aegypti in the state and be prepared if yellow fever or dengue fever become prevalent. According to the CDC, there have only been nine yellow fever cases in the U.S. between 1970 and 2011. California, meanwhile, has had 200 cases of dengue fever since 2010 but were contracted by the patients while traveling in other countries.
Yellow fever is generally asymptomatic but for people who develop symptoms, headache, nausea, body pain, backache, and vomiting are common. Only about 15 percent of patients tend to develop a more serious case of YFV infection.
Dengue basically has the same symptoms as yellow fever, with high temperature, muscle pains, joint pains, and headaches. Severe cases may become hemorrhagic dengue fever where bleeding due to circulatory failure is common.
The arrival of the Aedes aegypti in California adds to the headaches of health officials who are already battling West Nile, a virus also spreading via mosquito carriers. This year alone, California reported 275 cases of the West Nile virus.
Authorities have started spraying insecticides in affected areas and are advising residents to get rid of any stagnant water in their yards.