EAB Meeting Minutes
April 13, 2004
Ramon Ajero None
Jim Skarbek Speakers
Marcia Van Eden Chet Moore, CSU Dept. of Environ-
Dave Swartz mental and Radiological Health
William Zawacki Sciences
Ray Herrmann Jerry Blehm, Larimer County Health
Brett Bruyere Dept.
Dale Lockwood Guests
Marc Engemoen, Larimer County
Staff Public Works Dept.
Cheryl Kolus, staff liaison Rich Grossman, Larimer County Health Dept.
Jennifer Shanahan, League of Women Voters
Several citizen guests
I. Citizen Comments
II. Chair's Comments
III. Commissioner's Comments
IV. Approval of March Minutes
The minutes were approved with no changes.
V. Amendments to the Agenda
Board review of the draft Serenade Park issue report was added.
VI. Discussion Items
West Nile Virus – Chet Moore (CSU) and Jerry Blehm (Larimer County)
Chet Moore spoke about prevention and control strategies for West Nile Virus (WNV). Dr. Moore reviewed the virus’s transmission cycle, noting that usually the host is a bird, the vector is a mosquito and the dead-end hosts are horses and humans. How prevalent the virus is depends on factors such as weather and climate, as well as food, space and breeding sites for the hosts and vectors. By the time we see WNV in humans or even birds, Moore said, it’s already all over the environment. Most overwintering Culex spp. (the mosquito vector) are found in storm drains.
In 2003, adulticide was applied in Larimer County at the end of the mosquito season. There’s no real way to know if the number of WNV cases would have continued to rise if we had not adulticided.
Larviciding early in the season is effective and economical compared with adulticiding, and has the advantage of a more stationary target, since larvae are confined to particular habitats and are not flying around. When the virus is already circulating through the environment, however, larviciding is not as effective, and adulticiding is the best choice.
Regardless of which control strategy, if any, is used, educating the public and reducing mosquito habitats (such as standing water) is important to do throughout the season.
To larvicide effectively, we need to identify and map mosquito habitat (such as cattail marshes, irrigated pasture, etc.).
John Bartholow asked what triggers a switch in strategies from larviciding to adulticiding. Dr. Moore said it depends; all states are different, and several factors contribute to the decision-making process. The Centers for Disease Control’s Web site has a decision matrix to help government officials and others decide on the best control measures for the situation. Early control has a greater impact, but usually decision-makers want to wait to see if WNV cases rise or fall.
Someone asked if the CDC was checking immunity in sparrows or other birds. Dr. Moore said that in some species, such as crows, WNV is always fatal. Others, like sparrows, may recover and may become immune.
Ramon Ajero wondered if it was a change in the weather or the control measures put in place that helped last year. He asked if there’s a way to overlay weather and other factors to determine what causes what. Dr. Moore said they’ve been trying, but there’s not much initial data to use. Funding is coming in now and in another year or two, it’s hoped that there will be more information along those lines. California has been working on this for a little while though.
Trish Spain, a guest at the meeting, noted that we can’t always transfer data among different areas, due to differences in mosquitoes’ life cycles and weather patterns.
Another question asked was if it’s necessary to douse water bodies with larvicide within a certain time after rainfall. Some chemicals have a slow-release action, so multiple applications are not usually necessary. Jim Skarbek noted that this will only work in standing water. Mosquitoes are not found in running water, Dr. Moore said.
A guest asked how amphibians and other wildlife are affected by chemical controls. Other methods of control are suggested if the animal in question is used as a food source. Brett Bruyere asked if anyone is testing animals currently. Jerry Blehm said that WNV testing is done year round on birds, horses and humans.
Dr. Moore noted that it would be ideal to have random samples of treated and untreated communities to better test the effectiveness of controls. But of course, such an experiment would never be approved. It may be possible in cases where communities choose on their own not to use controls. In Michigan, communities that had long-standing mosquito control measures in place had fewer cases of WNV than those that used last-minute controls.
Someone brought up the question of how much media coverage affected the virus rate in humans by causing more people to stay inside, etc. This has not been measured, though.
When asked what the forecast for WNV is for this year, Dr. Moore stated that it is really unpredictable.
Dave Swartz asked if the county has a clearinghouse of suspected mosquito breeding sites, and if there’s a way to tap into the public to find those sites. Mr. Blehm said there is no such clearinghouse, but there will soon be a way for the public to input information. Satellite photos are helpful for finding big breeding sites, but there are thousands of small sites in hoof prints, empty cans, etc. One cup of water can hold 1000 mosquito larvae.
Jerry Blehm stated that Ohio reported its first (unconfirmed) case of WNV yesterday. Boulder, Larimer and Weld counties had a large amount of WNV cases in 2003. Loveland has been practicing mosquito control for years, even before WNV was a concern. Still, however, Loveland had more serious human cases than did Fort Collins.
Loveland will continue its control measures, and has already begun this year. Areas are mapped, a contractor does inspections, and when vector larvae are found, larviciding is done using three chemicals. Fort Collins will do some of the same things; it has hired the same contractor, and will map, monitor, and implement control measures out to the Timnath area. Fort Collins has no provision for adulticiding, though. Berthoud and Wellington also hired a contractor to map, monitor and control mosquitoes within their towns.
Larimer County will continue to monitor birds, horses and humans (through clinical data and blood donors). The county may do more testing in some areas and less in others, depending on findings (i.e. they won’t keep testing the same site if it’s tested positive). Public education is still the best method of controlling WNV. Individuals must protect themselves; if everyone does, we can potentially be free of WNV in humans. The county health department is hiring two temporary health educators to promote personal protection and mosquito habitat reduction.
Findings indicate that a large amount of vector mosquitoes breed in residential areas. In the right conditions, adult mosquitoes will appear just five to six days after eggs are laid. But getting rid of all mosquito breeding habitat is next to impossible, Mr. Blehm said.
The county and the Cities of Fort Collins and Loveland will set up a hotline that the public can use to report possible mosquito habitat. The county will be paying the state health department to do a retrospective study of last year’s situation, in which Loveland reported more WNV cases than Fort Collins, yet had implement more control measures. Could the difference in number of cases correlate with media coverage and/or personal behaviors?
Trish Spain, a guest, stated her concern that medical records are not accurate or consistent among different hospitals and clinics. Jerry stated that health officials are more concerned with the neurological cases, and that many other humans who just presented with fever were probably never tested.
Dave Swartz suggested using public schools as educational targets, but to do so would require acting quickly, as schools are only in session for another six weeks. Jerry said they would get into the schools with information as quickly as possible, and that they will also target summer recreational clubs, etc.
Jim Skarbek asked if any education was being targeted to the medical community. Jerry answered yes.
Marcia Van Eden asked if there were a possibility of having an open blood draw to test for WNV for those who want to. Jerry said the health department is emphasizing blood donations, since in Colorado, all donors must be tested for the virus. It would be too expensive and logistically difficult to offer free testing for everyone.
Ramon asked what else the county will be doing regarding WNV. Jerry said the county and cities’ Information Management Services employees will be helping develop a better data system. The Fort Collins, Loveland, Berthoud and Wellington areas have been mapped and Colorado Mosquito Control (CMC; the contractor) has looked at areas outside those city/town limits. Sixty to 100 square miles in the county have been identified for the county to map, monitor and control. The county won’t preclude adulticiding if necessary; it is a last choice, though. The cost of the amended mosquito control program in the county is about $100,000.
At least 30 mosquito traps have been set in Loveland, 35 in Fort Collins and 10 to 14 in additional areas (Wellington, Berthoud, Estes Park and Red Feather Lakes). This is three times the number of traps that were placed last year. Dr. Moore also has traps set.
Jack Coleman asked what natural predators prey on mosquitoes. Jerry noted that birds and bats do, but that they don’t seem to make that much difference in numbers of mosquitoes. Health officials do encourage use of bat boxes, though.
In response to another question, Jerry said that health officials are not positive that one can prove that larviciding reduces mosquito numbers or disease transmission.
The county does have reserves that could be used for mosquito control if the current amount budgeted is not enough.
Ramon asked about a new application method for larviciding that is aerosolized. Jerry was not familiar with it, but will check with Colorado Mosquito Control.
John Bartholow mentioned that part of the county’s master plan monitoring includes methods for scientifically following wetlands though time. John wondered if the satellite imaging being used to identify mosquito breeding sites could also help in wetlands monitoring. Jerry said he will talk to Jill Bennett in the Planning Department.
Ramon asked if any building or land use codes address housing near potential mosquito breeding sites or other health issues. Jerry said the codes do somewhat address health issues, as with prairie dogs (tularemia) and wetlands.
Bill Zawacki asked if cities need to look at their land use codes, too, regarding issues like cattails and drainages near public parks, etc. Jerry believes that storm drainage basins are designed to not hold water long enough for them to become mosquito breeding habitat.
We have only a little more than one year of data on Culex spp. as a WNV vector, which is not enough data to draw any real conclusions yet. More years of data exist on other mosquito species in other parts of the country.
Jack Coleman asked what preys on mosquito larvae. Dale Lockwood noted that mosquito fish do. Jerry said that lots of fish species prey on mosquito larvae in big water bodies. He doesn’t think there are enough natural predators, however, and that humans need to help control mosquito populations.
The board reviewed John Bartholow’s draft recommendation letter to the Board of County Commissioners regarding the draft Environmental Impact Statement (DEIS) on the Canada Lynx. Bill Zawacki asked what flexibilities are defined between Options C and D in the DEIS. John said that is difficult to determine. Ramon asked if the options would be universally applied to all forests listed. John believes that there would be forest-specific interpretations of the rules. Ray Herrmann noted that the standard for an EIS is that it applies to the forests listed, but it may vary by zone. Ramon asked for clarification on the difference between Options B and C. John explained that Option B is good if the goal is to put the lynx above everything else, but that Option C is more realistic and probably wouldn’t get as much backlash. Ray further summarized that Option D is simply “keep doing what we’re doing and the lynx will have to adapt,” Option C is a little better for the lynx, and Option B probably just wouldn’t be accepted in this area.
A motion passed that John’s letter of recommendation would be sent to the BCC with a few edits and the addition of a cover letter.
The board reviewed and discussed the Serenade Park issue report drawn up by Marcia Van Eden and Bill Zawacki. The issue report, with a few minor changes, will be posted on the EAB Web site.
Marcia Van Eden and John Bartholow noted that the field trip to Bacon Elementary, an Environmental Stewardship Award winner, was very interesting and that the school is doing really great things.
The meeting adjourned at 9:15 p.m.