Skip to main content

Spring 2017 Newsletter

Quarterly Newsletter and Updates Spring 2017 

Mosquitoes vs Midges 

Midges are small, harmless flying insects that resemble mosquitoes. The Alameda County Mosquito Abatement District is aware that midges are emerging in large numbers in areas of the county that are near channels, creeks, and large bodies of water. These insects pose no threat to pets or people and since they do not transmit any diseases, we do not control them. Midges are an important part of the food chain for local and migratory waterfowl. These insects are highly attracted to lights and "bug zappers." Minimizing the use of outside lights will help to reduce their presence near your home. Should you choose to use a "bug zapper," keep it far from your residence to maximize its effectiveness. 

Male midges form large swarms when temperature, humidity, and light conditions are right for their species. Adult midges are short lived, living usually less than 1 week. The adult life stage is merely to swarm, mate, and lay eggs. Adult midges can be easily identified by their habit of resting on surfaces with their bodies held very close to the substrate. Other midge-like insects (and mosquitoes) stand on the ends of their legs, with their bodies clearly not touching the substrate they are resting on.

Although midges do not bite, they often occur in large numbers and can be annoying. The following suggestions may help minimize their annoying presence: 
1) Outside lights can be changed to yellow, which are less attractive to these insects. 
2) Doors should be kept closed and windows tightly screened to prevent midges from entering your home. 

May contain: insect, animal, and invertebrate
                         Mosquito                                                                                    Midge



Wetland Restoration and Mosquitoes

On June 7th, 2016 residents of the nine-county San Francisco Bay Area voted to pass Measure AA, the San Francisco Bay Clean Water, Pollution Prevention, and Habitat Restoration Measure. This measure is a $12 parcel tax, which will raise approximately $25 million annually, or $500 million over twenty years, to fund projects that will protect and restore the Bay. With wetland restoration projects on the horizon, care must be taken to not create habitat for the many species of mosquitoes which thrive in our coastal wetlands. 

To make certain public health and mosquito related concerns are not over looked, Regulatory and Public Affairs Director, Erika Castillo has joined the 33 member advisory committee of the San Francisco Bay Restoration Authority. The goal for Alameda County Mosquito Abatement District's participation in this committee is to contribute to the success of marsh restoration projects in the Bay Area by ensuring that public health and the perception of wetlands are not negatively impacted by an increase in mosquito populations. 

Zika Virus 

Local transmission of Zika virus occurred in both Florida and Texas (the small striped areas on the map below) in 2016. Although there are many communities in California where the mosquitoes capable of transmitting Zika have been found, the disease has not been spread locally. Hundreds of California residents have acquired Zika virus while travelling abroad so it is important to always protect yourself from mosquito bites wherever you may be. The California Department of Public Health recently issued a press release reminding travelers to protect themselves from mosquito bites and Zika virus.

May contain: map, diagram, plot, and atlas
Zika virus cases in the U.S. ( as of 4/5/17

What you can do to help keep invasive Aedes mosquitoes out of Alameda County:

  • Inspect your yard regularly and remove any clutter or containers that may hold water.
  • If you store water, make sure all containers are tightly covered to keep mosquitoes out.
  • Scrub outdoor containers that have held water with hot, soapy water to kill any potential mosquito eggs.
  • Wear mosquito repellent when spending time outdoors.
  • Do not bring home items that have held standing water (tires, containers, plants, e.g. bromeliads, bamboo, etc.) from areas with invasive Aedes mosquitoes.  Click here to see areas in California with invasive Aedes.  To see the potential range of invasive Aedes mosquitoes in the United States click here.

If you will be traveling to an area with Zika virus:

  • Use insect repellent. Look for these ingredients: DEET, picaridin, IR3535, Oil of Lemon Eucalyptus, or para-Menthane-3,8-diol (PMD). Reapply often, as directed on the product label. Remember to apply sunscreen first and then insect repellent.
  • Cover exposed skin when possible.
  • Stay and sleep in screened-in or air-conditioned rooms. Use a bed net if you're sleeping outside.   
  • Watch for symptoms after you get home.
  • Call your doctor immediately if you suspect Zika.
  • Use insect repellent for 3 weeks after travel.
  • Use condoms when you have sex for at least 6 months.

Pregnant? Trying to conceive?

Zika is linked to birth defects. Pregnant women should consider postponing travel to any area with Zika. If your male partner travels to these areas, either use condoms or don't have sex for the rest of your pregnancy.

Additional Resource from the CDC 

West Nile Virus* 

May contain: plot, diagram, map, and atlas

West Nile virus (WNV) has already been detected in three dead birds in 2017, the closest to us being just across the bay in San Mateo County. Dead bird reports are crucial to our WNV surveillance program in Alameda County as they are typically our first indication of WNV activity. The state West Nile virus hotline for reporting dead birds (877-WNV-BIRD) is reopening on Monday, April 17th.  Until then, internet reporting for dead birds is available at Statewide totals for WNV activity in 2016 are 1,352 dead birds, 3,528 mosquito samples, 343 sentinel chickens, and 442 humans cases with 19 fatalities.  The totals for California's WNV activity are updated weekly and can be found at

*Data as of April  7, 2017

Alameda County WNV Activity

Quarterly Numbers


Upcoming Events

  • California Mosquito Awareness Week - April 16th - April 22nd
  • Peralta Colleges EcoFest Sustainnability Festival (Laney College, Oakland) - Thursday, April 20th, 11am-2pm
  • Alameda Earth Day Festival (Washington Park, 740 Central Ave., Alameda) - Saturday, April 22nd, 10am-3pm
  • Hayward Cinco de Mayo Festival (City Hall Plaza, Downtown Hayward) - Saturday, May 6th, 10am-5pm
  • Alden Lane Nursery Mosquitofish Giveaway (981 Alden Ln., Livermore) - Saturday, May 13th, 10am-2pm
  • San Leandro Cherry Festival (Downtown San Leandro) - Saturday, June 3rd, 11am-6pm
  • Alameda County Fair Display Booth (Alameda County Fairgrounds) - Friday, June 16th to Sunday, July 9th

All Events