Conditions Ripe for a Zika Outbreak in Pasadena, Say Experts

[Editor’s Note: This original story indicated Pasadena is the only city in Los Angeles County which maintains its own health department. In fact, a Long Beach also maintains its own health department.]

According to reports from state and local health authorities, conditions are ripe for a Zika outbreak in the San Gabriel Valley this summer.

The Zika virus causes microcephaly, a condition in which babies are born with an abnormally small head and brain.

“The breeds of mosquito known to be a transmitter of Zika (aedis albopictus aka Asian Tiger Mosquito and aedis aegypti) have both been identified in the San Gabriel Valley,” said Michael Johnson of the Pasadena Public Health Department (PPHD) last week.

“The potential is in place, and all of the elements are there, so it could happen one way or another,” said Jason Farned of the San Gabriel Valley Vector Control District.

While no locally-acquired cases of the Zika virus have been reported in the U.S. yet, 755 travel-associated cases have been reported, with 48 of those cases in California. Eleven of those cases was sexually transmitted.

A recent announcement from the Pasadena Health Department listed several precautions in the wake of the potential of a Zika outbreak:

• Pregnant women who have returned from an affected area should be tested for Zika virus infection if they have had symptoms suggestive of Zika virus infection during or within 2 weeks of travel, or if their fetus/infant has evidence of microcephaly or intracranial calcifications.
• Zika virus testing for Pasadena residents must be requested by calling Pasadena Public Health Department Communicable Disease at (626) 744-6043. All other requests for Los Angeles County (LAC) residents must be made by calling the Acute Communicable Disease Control Program (ACDC) at 213-240-7941.

A map provided by the California Department of Public Health shows that nearly three dozen cities in Los Angeles County have already identified the presence of the Zika-transmitting mosquitoes.  (To view, click here: http://www.cdph.ca.gov/HealthInfo/discond/Documents/AedesDistributionMap.pdf )

Pasadena is one of two cities in Los Angeles County with its own health department (Long Beach being the other), and according to Johnson, shares its findings with other local and state vector districts and public health agencies.  The Pasadena Public Health Dept. does operate a Vector Control Program through their Environmental Health Division, however they are not a member of the San Gabriel Valley Mosquito Abatement District.

“Aedes aegypti or Aedes albopictus mosquitoes have not been detected in Pasadena so far,” said Matt Conens, of the office of Public Affairs, California Department of Public Health, “but it is possible that there is an infestation that has yet to be detected. It is important for Pasadena residents to report day-biting mosquitoes to the Environmental Health Department so a follow-up inspection can be conducted. Those reports can assist Aedes detection efforts.”

Currently, mosquito and vector control districts are reporting new Aedes infestations to the California Department of Public Health daily. This information is added to the Aedes map, which is updated every Friday, according to Conens.

Meanwhile, the San Gabriel Valley Vector Control District (SGVCD) constantly monitors potential infestation, as well as “green,” unattended swimming pools. According to Farned of the SGVCD, an unattended pool can breed up to 3 million mosquitoes a month.

As no infestations have as yet been detected, said Johnson, “It is important that the best practices of mosquito prevention take place to prevent transmission of Zika, adding that, “the PPHD conducts visual surveillance of identified standing water and will apply larvicides to prevent mosquito breeding throughout the spring-fall mosquito breeding season.   The more common breed of mosquito in this area which is a known breeder of West Nile Virus and St Louis Encephalitis is the culex mosquito.”

Johnson also added that if an individual becomes infected with Zika while traveling abroad, they may never transmit it locally.

“Zika is not transmissible from person to person in casual contact,” continued Johnson, who said, “It could transmit to the mosquito population, however there are several actions in the mosquito life-cycle necessary for this to occur, so it is generally a low risk unless a larger percentage of the population is infected by Zika.”