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Spring 2016 Newsletter

Stay up to date Spring 2016 
May contain: human and person

West Nile Virus

Alameda County has not had any West Nile virus (WNV) activity yet in 2016.  Statewide, 8 birds from 3 counties (Los Angeles, Orange, and San Diego) have tested positive for WNV.  California WNV activity can be found at

Events & Presentations

  • Dublin St. Patrick's Day Celebration - 3/12 & 3/13
  • Oakland Earth Expo - 4/6
  • San Leandro Earth Day/Watershed Festival - 4/9
  • Berkeley Bay Festival - 4/16
  • CSU East Bay Hack Day - 4/16
  • Chabot College Return of the Swallows Festival - 4/19
  • Camp Parks Earth Day Festival - 4/22
  • City of Alameda Earth Day Festival - 4/23
  • Tropics Mobile Home Park Senior Resource Fair - 4/30

See All Upcoming Events 

Mosquito Avoidance Tips

  • DUMP/DRAIN any standing water.  
  • DAWN/DUSK is when mosquito activity peaks, so limit outdoor activities during this time.
  • DEFEND yourself by wearing long pants and long-sleeved shirts and apply insect repellent containing DEET, Picaridin, IR3535, or Oil of lemon eucalyptus.
  • DOOR/window screens should be in good repair with no tears or holes.

See our checklist of common mosquito breeding sources.


Mosquito Life Cycle

Mosquito lifecycle
Mosquito Life Cycle

The winter months are passing by and adult mosquito activity will soon begin to increase.  In Alameda County mosquitoes breed year-round.  However, the majority of our native mosquito species are still in their larval form during the winter months.  In an effort to reduce springtime mosquito populations, our staff continue to treat for larval mosquitoes throughout the winter months.  Targeting mosquito larvae is the most effective way to control mosquitoes.  So remember, dump and drain any standing water on your property to keep mosquitoes from breeding in your yard!  

Read more about our mosquito control program. 

District News

Operational Report

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Argos are used to treat mosquito larvae in several marsh areas

District employees have been busy during the last few months treating larvae of our main winter mosquito species, Aedes squamigerAedes washinoi, and Culiseta inornata. Increased rain levels this winter created sources of standing water where mosquitoes could breed that did not exist in previous years.  Each rain event can also trigger a new hatch of Aedes mosquito larvae.  Our native Aedes mosquitoes can be found breeding in a variety of habitats, such as saltwater marshes, freshwater marshes, flooded woodlands (especially those that contain willow trees), and even tree holes (rotted out cavities in the trunk of a tree). Treatments of larval  Aedes sierrensis, the treehole mosquito, will continue over the coming month. Treehole mosquito adults typically begin to emerge around the Spring equinox. 

More information on Alameda County mosquito species. 

Laboratory Report

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Surveillance of adult mosquito populations also continued throughout the winter months.  New Jersey light traps (pictured to the right) are distributed among the county and checked on a weekly basis.  Overall, the number of adult mosquitoes in Alameda County right now is low.  As the season begins to change, more mosquito surveillance traps will be placed in areas with known mosquito breeding sources to monitor mosquito activity.  In addition, surveillance for invasive mosquitoes such as Aedes aegypti and Aedes albopictus (the mosquitoes capable of transmitting dengue, chickungunya, and Zika) will expand as well. 

More about District surveillance efforts. 

Zika Virus
Zika virus is making headlines worldwide.  With so much information about Zika in the media it can often be difficult to keep up.  Here are a few things about Zika you should know:

  • Zika virus is most commonly spread through the bite of an infected mosquito.  However, evidence also points to sexual transmission.
  • Aedes aegypti (the yellow fever mosquito) and Aedes albopictus (the Asian tiger mosquito) are the primary vectors.
  • Aedes aegypti and Aedes albopictus are not native to California but they have been introduced in several California counties. (see map)
  • Aedes aegypti was detected in Alameda County in May of 2015 (2 adult mosquitoes were found) but has not been found since.  Surveillance is ongoing throughout Alameda County for invasive Aedes mosquitoes.
  • If traveling to an area with active Zika virus, avoid mosquito bites by wearing mosquito repellent containing either DEET, Picaridin, IR3535, or Oil of Lemon Eucalyptus.

For more information on Zika virus visit the California Department of Public Health or the Center for Disease Control and Prevention websites.

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Current Research and Presentations 

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Entomologist, Eric Haas-Stapleton, PhD (left) and Biological Specialist, Dereje Alemayehu (right) next to their posters at the MVCAC annual conference in Sacramento

 The California Mosquito and Vector Control Association of California (MVCAC) held it's annual conference February 28 - March 2, 2016 in Sacramento, CA.  Several members of the office and field staff were in attendance.  Two posters were presented by laboratory staff, "Mosquito trap modifications for improved utility in abundance monitoring" and "Comparison of RNA extraction methods for detecting viruses in mosquitoes: MagMAX wins!"



Quarterly Numbers  (December - February)

Total calls received = 194 (10 yr. avg.= 110)  

  • Mosquito biting reports = 35
  • Mosquitofish requests = 88
  • Preventative calls  = 67
  • Miscellaneous insect identifications = 4

Mosquito sources inspected = 406

  • Mosquito sources treated = 190

Dead birds tested = 8

  • WNV positives = 0

Mosquito pools (a group of <50 mosquitoes) tested = 4

  • WNV positives = 0