A baby born recently in San Diego County is the first in the region to suffer birth defects after the infant's mother contracted the Zika virus while traveling abroad.
Public health officials said the case, announced Tuesday by the county government, is a reminder that the risk of Zika infection continues in warmer climates even though mosquitoes are dormant in San Diego.
"[While] there is currently no local spread of Zika, we still want to remember that we all have to be vigilant in protecting ourselves and our community from diseases like this," said Dr. Sayone Thihalolipavan, a deputy public health officer with the county Health and Human Services Agency.
Pregnant women are urged to avoid going to countries where mosquitoes are actively transmitting the virus. Those who absolutely must travel to such locations are recommended to follow strict guidelines designed to prevent mosquito bites, including the use of an effective repellent and wearing long-sleeved shirts and pants.
Little information was released Tuesday about the local family. Citing privacy concerns, the county health department declined to disclose the child's birthdate or gender, or the country the mother had visited. The Zika medical crisis stretches from Mexico and South America to Asia.
A total of 87 people in San Diego County have tested positive for Zika, and all of the infections occurred while the patients were in other countries. Seven of those individuals, including the mother in the recent birth defect case, are or were pregnant during their infection period, Thihalolipavan said.
Travel-related Zika concerns have created such a steady stream of requests for information from the county health department that an extra expert was hired, he said.
"Some days we'll have just one or two calls, but often we'll have 10 to 20 per day where we're working with [medical] providers who need more information," Thihalolipavan said.
Two of the region's 87 infections were spread through sexual contact, he said. One was transmitted from mother to baby before birth but did not cause microcephaly, the most common birth defect associated with the virus.
Microcephaly is the medical condition in which a baby is born with a head that is smaller than normal. The birth defect may cause no significant symptoms at birth, but many children with the condition later develop epilepsy, cerebral palsy, learning disabilities, hearing loss and vision problems, according to the World Health Organization.
Some children with microcephaly experience normal development, and science has not figured out what spares certain kids but afflicts others.
In fact, scientists are trying to determine why most children born to Zika-infected women do not have birth defects. According to the U.S. Centers for Disease Control and Prevention, 1,228 pregnant women in the United States have been infected with Zika as of March 14. Fifty-four babies have had birth defects, and seven pregnancies have been lost because.
Nationwide, there have been 4,861 travel-related cases of Zika, with an additional 222 presumed to be "locally transmitted" by mosquitoes in the United States. According to the CDC, 216 of the locally transmitted cases occurred in Florida, and the remaining six took place in Texas.
California has recorded 434 cases of Zika.
The Aedes aegypti mosquito transmits Zika and recently has become active in San Diego County. Chris Conlan, the county's supervising vector ecologist, said while the region usually starts seeing some mosquito activity as early as May, the aegypti variant gets a later start.
"The mosquitoes that can transmit Zika tend to get more common later in summer, from August to October," Conlan said.
To prevent mosquito bites, San Diego County health and insect-control officials recommend using insect repellents that contain DEET, picaridin, IR3535, lemon oil, eucalyptus oil or para-menthane-diol. Sunscreen should be applied before any repellent, and pregnant or breast-feeding women should use an EPA-registered product and follow instructions on the product's labeling. Repellent should not be used on infants 2 months or younger.
Before booking a trip, people are advised to check the CDC's travel warning page at cdc.gov/travel/notices for nation-specific information.
According to the WHO's latest Zika report, countries with active transmissions include:
- American Samoa
- British Virgin Islands
- Cayman Islands
- Puerto Rico
- The Bahamas
- The Maldives
- Trinidad and Tobago
Sisson writes for the San Diego Union-Tribune.