Printer-friendly versionPrinter-friendly version Share this


By Miriam Raftery

December 14, 2015 (San Diego)--A rare but serious birth defect in Brazil has been linked to a mosquito—the Aedes aegypti species, which has recently been found in San Diego County.

This type of mosquito was already known to carry diseases such as Yellow Fever, dengue fever, chikungunya and the Zika virus.  But now the Zika virus is suspected of causing microencephaly, a rare neurological disorder that results in infants having small heads and underdeveloped brains, resulting in severe developmental issues. The mosquito bites an expectant mother, transmitting the disease to her unborn child.  Babies born with this illness are likely to die young and require constant care.

In Brazil, the situation is so serious that the Ministry of Health has urged women in the northeast part of the country not to get pregnant. Doctors in the region, where the mosquitoes are prevalent, are seeing a growing number of infants born with microencephaly, NPR reports.

Doctors there discovered that most of the mothers of babies born with microencephaly had the Zika virus early in their pregnancies. While Zika virus in most people causes only mild illness, its impact on an unborn baby may be far more severe.

Brazil’s health officials are working with the World Health Organizations and the U.S. Centers for Disease Control and Prevention to research the health crisis, while the government is also working to eradicate the mosquito that spreads the disease.  Meanwhile, six states in Brazil have declared a state of emergency.

The Aedes aegypti mosquito first reached Brazil in the mid-1900s aboard slave ships from Africa, but a yellow fever outbreak let to a major effort that nearly eradicated the dreaded pest.  But now it has rebounded.  The mosquito is now so prevalent that over a million and a half cases of dengue fever have also occurred in Brazil this year, likely linked to the same mosquito.

Climate change is a key reason for the mosquito’s spread.  Due to drought in Brazil, people have been storing water on their rooftops – water that attracts the mosquitoes, which breed in standing water. 

Climate change may also be responsible for the tropical mosquito expanding north.  For the first time, several of the Aedes aegypti mosquito were found in San Diego, Chua Vista and Escondido earlier this year. The best way to prevent them from spreading locally is to not provide any standing water in which they can breed. 

Here are tips for identifying this invasive mosquito:

  • It usually feeds during the day and is an aggressive biter. Most native mosquitoes prefer to feed between dusk and dawn.
  • It likes to live in urban areas — feeding and laying eggs not only outside, but inside people’s homes in almost anything that can contain water, including plant saucers, cups and flowerpots.
  • It is small and black with white stripes.

The county has tips on how to control these pests, report green pools and eliminate standing water, or report sightings of the mosquito to the County Vector Control Department here:

The consequences of not controlling the Aedes aegypti mosquito’s spread are potentially very severe.

Infectious disease expert Dr. Angela Rocha in Brazil warns, “If we don't get a handle on this, we are going to have a generation of damaged babies."


Error message

Local news in the public interest is more important now than ever, during the COVID-19 crisis. Our reporters, as essential workers, are dedicated to keeping you informed, even though we’ve had to cancel fundraising events. Please give the gift of community journalism by donating at