It is that time of year. With all the rain and standing water in the valley one would expect high numbers of mosquitoes.
Ben Prather, the vector control specialist for Cass County, said modern techniques are used to find and treat the areas where mosquitoes are known to hang out. The Cass County crew has been using GPS devices to track and monitor locations which are treated with larvae pellets. “Currently we have about 30 seasonal field aides licensed in mosquito control and 2.5 full time staff: myself, a field ops manager, and a technician that works for us in the summer repairing equipment who spends the rest of the year working for the highway dept.”
“We spray for mosquitoes as early as March and continue treating standing water through the first hard freeze. We basically find and kill mosquitoes any time temperatures are warm enough to sustain them. I have sampled mosquitoes from underneath ice as thick as one inch in late February and early March,” says Prather.
“Typically we ‘fog’ in the evenings and mornings. We apply other materials to public spaces, parks, and areas of mosquito harborage (anywhere with long grass or weeds really) – much like home owners do on their own properties but at a more industrial scale. That type of application or “spraying” occurs in late May and ends in September,” Prather advised.
“We often spray “under threshold” when we start to see an abundance of cx tarsalis mosquitoes – WNV (West Nile Virus) transmitting mosquitoes. These applications usually occur in July through August but can occur at any time. WNV transmission correlates directly to ambient temperatures. High temperatures speed WNV along more quickly.”
The WNV causes infection in humans, birds and horses when they are bitten by an infected mosquito. There is no evidence that West Nile Virus can spread from one person to another or from an animal to a person. According to: http://www.metrofightthebite.com/WestNile.htm: “WNV is transmitted by infected mosquitoes, primarily Culex, Aedes, and Ochlerotatus species. Mosquitoes become infected after biting infected birds that serve as the primary host of the virus. The virus undergoes a reproductive cycle inside the mosquito, in which it must pass through the midgut wall, multiply in many tissues, and accumulate in the salivary glands of the mosquito. Mosquitoes salivate every time they bite, and they are capable of transmitting the virus 10 to 14 days after feeding on an infected bird, so bites after that time are infectious.”
Avoid harboring mosquito nesting sites by removing old tires, buckets, toys, or anything that can hold water, clean clogged gutters, properly care for birdbaths, wading pools, fountains, etc. Make sure your sump dump drains adequately. Keep grass and weeds trimmed well. Treat places that harbor mosquitoes with larvicides like “BTI,” “mosquito dunks,” and “Altosid” found at home improvement stores. When treating your property, be sure to cover decorative ponds as the chemicals are toxic to fish. Keep children and pets away from application areas until they are dry or for a minimum 30 minutes. The Minnesota Department of Health provides information on using mosquito repellents safely at: http://www.health.state.mn.us/divs/idepc/dtopics/mosquitoborne/prevention.html
Prather said, “The incidence for West Nile virus in North Dakota has been some of the highest historically in the country. The last two years, however, have seen a waning trend in WNV infections – in 2010 our incidence of WNV was about 1 case per 400,000 residents, whereas in 2007 we were more like 50 cases per 100,000 residents.
“2009 was very similar to 2010 in terms of WNV cases. From a broad perspective it looks as though the virus has backed down throughout the North American continent. This is a good thing. However, there is already one known mutation isolated early on in about 2000, and it is not impossible for another round of infection to occur. Cass County Vector is still monitoring and actively engaging WNV vectors.”
Prather said the mosquito operations are funded primarily by individual municipalities, with Fargo and West Fargo comprising about 85 percent of the local operations, and are about 85 percent of the department revenue. “They supply funds to better maintain their comfort levels. Expenditures vary from year to year depending on conditions. Last year we spent about 1.3 million dollars, roughly double the expenditures in 2009,” said Prather. Many smaller, rural communities contract with Cass County for vector control.
“There is no real way to control tick populations,” Prather advised. “They travel on hosts — deer, mice, etc. — and are notoriously resistant to pesticides. Currently I know of no government efforts to control tick populations through the use of pesticides.”
Ticks
“A lot of people still think they drop off trees – most of the deer ticks’ lives are spent in leaf litter on the ground. Most get on down low and walk up.” says Dave Neitzel, a Minnesota Department of Health (MDH) epidemiologist specializing in disease carried by ticks and mosquitoes.
Mid-May through mid-July is the primary time for Lyme disease. Eighty percent of the cases occur during this time. “This corresponds to the immature lymph stage of the black-legged (deer) tick when they are so small and hard to see. The adult stage is active in fall and females can transmit the disease. They are bigger and easily seen,” in the fall, says Neitzel. “Carbon dioxide attracts ticks and they crawl up to the mouth to find it. Wear a good repellent, like a mosquito spray with DEET, to repel them.”
Lyme disease, human anaplasmosis, asbestosis, Rocky Mountain spotted fever, southern tick-associated rash illness and human monocytic ehrlichiosis are the commonly recognized tick-born diseases. The numbers of people infected in Minnesota diminish as the list wanes. The last three infections are rare in Minnesota, found mostly on people that travel to the south-central United States.
That being said, Lyme disease and human anaplasmosis numbers in Minnesota are on the rise.
According to the Department of Health:
Signs and Symptoms of Lyme Disease
The signs and symptoms of Lyme disease vary among individuals. A person may not have all of these symptoms. People often feel like they have the flu.
Three to 30 days after a deer tick bite, look for:
–A distinctive rash
–Fever
–Chills
–Muscle and joint pain
–Fatigue
Days to weeks after onset of illness, one of more of these signs and symptoms may occur:
–Multiple rashes
–Facial paralysis on one side of the face
–Fever
–Stiff neck
–Headache
–Weakness, numbness or pain in arms or legs
–Irregular heart beat
–Persistent weakness and fatigue
Weeks to months after onset of illness, some of these signs or symptoms may appear:
–Arthritis in one or more joints, usually the knees
–Problems with nervous system
–Persistent weakness and fatigue
The Minnesota Department of Health Fact Sheet provides these suggestions for prevention and treatment of Lyme disease:
–Use a good tick repellent which contains Permethrin and DEET (products should not contain more than 30 percent DEET and should not be used on children under the age of two months), typically sold where camping and hunting supplies are found. These products should not be put on the skin, but on clothing.
–Wear clothing to protect you from ticks such as long-sleeved shirts, pants tucked into the top of your socks, and light-colored clothing to make it easier to see ticks if they are crawling on you.
–Check often for ticks and remove them promptly. If possible, use a tweezers and grab the tick as close to the skin as possible, pulling firmly upward.
–Ticks actually need to bite and remain on the skin for 24-48 hours to transmit the bacteria.
Treatment following a tick bite can prevent long-term ramifications. In some cases, a 1-day antibiotic treatment might prevent development of Lyme disease but only under certain conditions:
-the tick must be verified as a black-legged deer tick;
-the tick must have been attached for about 36 hours, and if it is full of blood the tick has been on the site for long enough to pass the bacteria;
-the local infection rate in the blacklegged ticks must be at least 20 percent;
-the treatment is only for people over 8-years old.
Many other organizations have information about Lyme disease. Check out the web for the Centers for Disease Control, the Mayo Clinic, and the American Lyme Disease Foundation.
We wait a long time in the valley to enjoy the summer temperatures and sunshine. Don’t miss out on summer fun. Don’t let mosquitoes or deer ticks cause illness to you or your family. Take the precautionary measures you need to prevent these nasty bites. Check loved ones for deer ticks after you have enjoyed the outdoors. Don’t let these suckers wreck your summer fun!