Vector, Rodents & Insects

Insects, Ticks, Mites & Rodents of Public Health Concern

Historically, several types of insects, ticks, and rodents have played a significant role in human health.  Insects, like mosquitoes and fleas, have long been carriers of diseases that have seriously impacted the human population.   Certain species of mosquitoes can spread diseases like malaria, West Nile virus, Dengue, and Zika to name a few.  Fleas, along with certain rodents, are the primary sources of plague outbreaks.  Ticks are known to infect humans with diseases like Rocky Mountain Spotted Fever, Tick-borne Relapsing Fever, and Lyme Disease.  In Idaho, Deer Mice are known carriers of the Hantavirus.

Some other insects of public health concern have included lice and bedbugs.  They are not normally associated with spreading disease (though body lice are capable of transmitting certain diseases).

The Human Itch Mite is a microscopic parasite that can burrow into the upper layer of skin and lay it’s eggs.  It causes a condition called scabies where the infected skin becomes very itchy and a pimple-like rash forms.  The mite is only transmitted from human to human.  They do not pass onto pets like cats and dogs.  There are no over the counter medicines available to treat scabies.  They are only available through a prescription.

Vector-Borne diseases are viruses, bacteria, and parasites that can cause illness and are transmitted by an arthropod (insects and arachnids).  The most common vectors are mosquitoes, ticks, and fleas.  Globally the best known vector-borne diseases are malaria, dengue, Lyme disease, West Nile virus, plague, and Zika virus.  In Idaho, the vectored diseases seen most frequently are West Nile virus, Rocky Mountain Spotted Fever, Tick-borne Relapsing Fever, Lyme disease, plague, and tularemia.  Currently, the tick that spreads Lyme disease has not been identified in the State.

If you would like to learn more about these diseases, please visit the Centers of Disease Control website.

If you would like to see the number of cases each year in Idaho, you can visit “Idaho Reportable Disease Summaries” at the Idaho Health & Welfare website.

Bed Bugs

While bed bugs are not known to carry any diseases, they can cause a great deal of stress on the human body.  Bed bugs are well known around the world.  The adults have flat, dark reddish-brown bodies near the size of an eraser on a pencil.  Their eggs are white and can be difficult to spot.  They have five stages of growth between the egg and adult stage.  After they hatch out, the “nymph” will begin as white and will start to darken after they start to feed on blood.  They will steadily get bigger, with the juvenile looking much like a smaller adult.  They need to have a “blood meal” between each of these growth stages.  A “feeding” will take approximately 5 to 10 minutes.  The bed bug saliva has properties that keep a person from feeling the pain of the bite and to keep the blood from clotting.  Some people will have no reaction to the bite, while others will begin to itch around the bite marks.  In some cases, a person will develop an allergic reaction.  Some people can take a couple of weeks before they start to react to the bites.  The most common signs on the skin are red, itchy, slightly raised bumps in the skin.  They can appear to be a rash that has formed on the skin like hives.

Bed bugs will most commonly be found along the mattress seams near a wall.  If they’ve been there for a few months, there will likely be a mix of adults, juveniles, and while eggs/nymphs along the seams.  There will be dark brown or black spots along the mattress where the bed bugs defecate the digested blood.  Bed bugs are not normally seen during the day and try to stay hidden until it is dark and they sense a person or animal they can feed from nearby.  While the bed is the most common spot to find them, they can also be found in other furniture, electrical sockets, loose wallpaper, and carpet.

If found, contacting a licensed exterminator is recommended.  Even with a professional involved, it will take come effort to ensure the problem is resolved.  Do not move the mattress through the house without first enclosing it into a sealed bag to ensure you do not spread them throughout the home.  Getting special mattress and box spring covers meant to trap the bed bugs already in the box springs/mattress and to keep others out, can allow you to keep the bed until you can feel confident that the trapped bugs are dead.  Keep in mind that bed bugs typically live between 6 months to a year.

Bed bugs are very resistant to most insecticides.  Most treatment methods are more physical.  Special heat treatments are very effective, but can be costly.  If an item (clothing, bed cloths, stuffed animals) can safely go into a dryer, then running the dryer on high for thirty (30) minutes can kill the bugs.  If an item cannot be placed in a dryer or discarded, then sealing it in an air tight bag or container for a year should work.  Regular vacuum cleaning can help pick up both eggs, nymphs, and adults, but make sure to empty the contents in a sealed bag and placed in an outside trash can.  Steam cleaning the carpet is also recommended.

To avoid getting bed bugs, avoid used furniture unless it has been inspected and determined to be safe.  Inspect recently purchased clothes around the seams for signs of bed bugs.  When traveling, check the mattress around the headboard for signs of bed bugs.  Don’t leave your luggage on the bed or furniture.  Use the luggage rack.  When you return home, put your luggage into a bathtub and inspect it carefully.  Try to keep contained until the clothes can be washed and dried.

For more information, call 208-455-5400.

Mosquitoes

Mosquitoes are well known for transmitting diseases to people and other animals.  Mosquitoes main diet is actually nectar from flowers.  However, the female mosquito requires a blood meal to acquire a protein source for her eggs.  Mosquitoes lay their eggs in static water or in damp areas that will later be flooded.  Once conditions are good, the egg will hatch out and go through several larval stages.  The larva feeds on organic matter and microorganisms in the water.  They must remain near the surface of the water for the majority of time in order to breath oxygen.  They can dive for short periods of time.  If the water is moving sufficiently, then the larva could drown.  Once they have fed and molted several times, the adult mosquito will emerge.  Mosquitoes will feed on mammals, birds, crocodiles, and amphibians.

One way to control mosquitoes is to deprive them of a place to lay their eggs.  This could be draining plant saucers, bird baths, basically anything that would hold water for at least a week.  Keep house gutters cleaned out and make sure covers over boats or other items are not holding water.  If they don’t have static water to lay their eggs, they will move on.  Just remember it doesn’t take much water.  A small pop can with water in it can still allow for hundreds of mosquitoes to grow into adulthood.

If eliminating the water source is not possible, then look for ways to make it unusable.  A pond with a fountain that keeps the water from being static will drown the mosquitoes.  Fish will also eat the mosquito larva.  Keep pools in good condition with the filters continually cycling the water.

Another possibility is adding a larvacide to the water.  Bacillus thuringiensis israelensis or Bti, is a naturally occurring bacterium that was found to kill mosquito larva when it was eaten.  It is widely used and has not been found to be dangerous to other forms of life.  Mosquito Abatement Districts regularly use this to help control mosquitoes.  It can come in several different forms, including granules, liquid, and donut-shaped “dunks”.  There is also a larvacide called methoprene.  It is an insect growth regulator that will keep the mosquito from becoming a fully functional adult.  Both are found regularly in retail stores that carry pest control and garden products.

Once the mosquitoes become adults, they are much harder to control.  If you live inside a mosquito abatement district, contact them and ask for their assistance.  If you don’t want them to spray a pesticide to control the mosquitoes, you can still discuss any alternative options.  If you do not live inside a mosquito abatement district, then you can contact a pest control company.  You cannot allow the pesticide to drift off your property onto another’s property unless they agree to it.  Because of this, wind speed and direction is very important.  There are also “barrier” sprays that can be applied to the undersides of leaves where mosquitoes typically rest during the day.

Personal Protection

Use a repellent when you are spending time outdoors, especially in the evening, early morning, and overcast days.  Only spray exposed skin and clothes and wash the repellent off once you are back indoors.  Do not use on a child’s hands to keep them from ingesting the chemical.  Do not spray the repellent onto the face.  Spray it on your hands and then pat it on the face.  Permethrin can be sprayed on tents or clothes (allow to dry prior to wearing), but do not spray it on yourself or others directly.

Try and keep mosquitoes out of your home by keeping window and door screens in place and in good condition.  If you are unable to keep mosquitoes from entering the home, consider mosquito netting about beds and cribs.

Most mosquitoes are active on overcast days, in shady areas, and at dusk/dawn.  There are some species that can be active during the day.

If you have questions, please contact 208-455-5400. If you live inside a mosquito abatement district, please contact them.

Mosquito Abatement Districts located within SWDH boundaries (PDF).