Bloodsuckers in the Backyard: Mosquitoes

Enjoying a summer’s day is something most people look forward to, but if that day turns into a slap festival, it can drive everyone indoors. Nothing can ruin a day faster than being attacked by mosquitoes and it can be especially distressing if you plan to extend that day into the evening, a time when mosquitoes are very active. Mosquitoes are not only an issue because they make you itch and scratch, but they can carry terrible diseases as well. While many of those diseases were common only to places like Africa, today West Nile Disease has reached every state in America and who knows if other diseases couldn’t one day transfer over as well.

For some unknown reason, some people don’t seem to be bothered by mosquitoes. However, there are estimates that one out of every ten people is highly attractive to them. These people find that they cannot leave their homes without spraying or slathering on mosquito repellent, which can easily be forgotten or disregarded when an outing is unexpected. As long as mosquitoes are a part of our lives, we must do what we can to protect ourselves from them and there are plenty of helpful ways to do so.

About the Insect

Female mosquitoes (who live for 2-weeks to a month) will lay eggs in any standing water, even the smallest amount can become a nesting area, as long as the water is present for around 5-days, the larva will survive. Mosquitoes will go through 4-stages in their life; from egg, to larva, to pupa, and then adult. The male of the species do not bite. The females only do because they require the proteins in blood to sustain their young and they love to feed at dusk and dawn, when temperatures are coolest. The heat of the day drives them into cooler hiding places, which is why people are usually most annoyed by them when sitting in the shade of a tree, on cloudy days or when near waterways. In warmer climates, mosquitoes are year round, but in cold climates, they will hibernate through the winter months.

Mosquito’s mouths are like a syringe needle that can draw blood up into their bodies much like a straw in a drink does. There are around 3,500 species of mosquito in the world, but only some feed on humans. Since a new mosquito can mate within 3-days of emerging and eggs can hatch in 3-days or less as well, the percentages of young can grow quickly. A female will also lay her eggs and move on to find a new mate immediately, this is why one quite often is surrounded by a swarm rather than just one or two mosquitoes.

• Species Description Characteristics of the mosquito, its natural history, and human connections.

• Invasive Species The U.S. Department of Agriculture’s profile on the Asian tiger mosquito.

• Featured Creatures article and images focusing on the life cycle of the common Asian tiger mosquito

Malaria

Malaria is a fatal blood disease carried by Anopheles mosquitoes and according to the World Health Organization, is blamed for more than 2.7 million deaths each year. The disease changes the adhesive cells it inhabits and it also digests the hemoglobin of red blood cells. If these infected blood cells stick to the capillaries within the brain, it will obstruct the flow of blood. This is called cerebral malaria and it is the most dangerous possible effect of the disease.

Malaria occurs in large areas of Central and South America, Africa, the Indian subcontinent, the Middle East, Southeast Asia, and Australia. From first infection it only takes two-weeks for the spores to multiply in the liver to thousands, which eventually causes the blood cells to rupture out into the bloodstream. The process continues as they multiply, infecting more red blood cells as they go. When a clean mosquito bites an infected person, they then pass the infection onto the next person they bite and thus the cycle continues. Patients suffer chills, fever and sometimes anemia and jaundice. There is no vaccine for Malaria, so indigenous people and those who travel to infected areas are always at risk.

• Health Protection Agency a resource for travel - Provides an overview of the disease, areas, prevention measures, and links to other malaria and tropical medicine sites.

• Malaria This CDC site offers a description, health links, maps and other helpful tools regarding Malaria

• Med Line Plus Description of the disease, as well as FAQ’s, research, helps and other tools. 

Breakbone/Dengue Fever

Also known as breakbone or dandy fever, Dengue (Deng-gay) Fever is caused by a group of viruses that are carried by the striped Aedes aegypti mosquito and usually strikes those with low immunity. The onset of the illness is sudden and the sufferer will have symptoms such as a headache, exhaustion, fever, joint pain that is severe and can contort, a rash, muscle pain and swollen glands. The virus can be caught more than once, because four different types of the virus cause it. However, once you have contracted one specific strain, you become immune to that one.

The most severe and possibly fatal form of the illness is called Dengue hemorrhagic fever and includes the headache, fever and rash, but adds other symptoms to the mix. Red or purple blisters form under the skin, the gums and nosebleed; people may easily bruise and have black stools, which may be due to hemorrhaging. Dengue is found in the tropics and subtropics, parts of Asia and Malaysia, but can also be seen in the Caribbean, Virgin Islands, Puerto Rico as well as other areas of the world.

• Aedes aegypti and Dengue fever article about these diseases, by Roland Mortimer of Rio de Janeiro.

• Campaign Against Dengue what is Dengue fever, hotspots, breeding sites and how to prevent infection.

• World Health Organization Dengue/dengue hemorrhagic fever – Its impact, activities, and more information.

Impact of Climate Change on Mosquitoes

Although there is some debate on the subject of global warming, scientists fear that a rise in global temperatures could be a potential health issue when it comes to mosquito transmitted disease. Higher temperatures would give way to shorter winters and enhance the conditions most favored by the insect. Was that to happen there is fear that there could be an increase in the four diseases, malaria, yellow fever, dengue fever, and West Nile disease. Study models have shown however that the mosquito’s range usually doesn’t vary much and therefore there may not be any significant change.

• Mosquito-Borne Disease Abstract of the affects of climate change and disease; includes sections on the future outlook, commentary and links to related articles.

• Impacts of climate change Article discusses the climate changing in Australia and how mosquitoes may play a role.

• Warmer = buggier? Site considers the repercussions of climate change and disease.

Efforts to Control Mosquitoes and Diseases

Over the years, there have been many methods used in order to control the mosquito population, all worked to one degree or another, but diligence at homes and businesses really makes the difference. Insecticides can kill larvae in their habitats, but insecticides can also be dangerous to both humans and other wildlife. Instead, organic pesticides can be used or natural predators can be introduced to the area. Those would include certain fish and dragonflies. Often the best thing to do and the most simple, is that of removing standing or stagnant water from areas surrounding your home or business, this simple act can eliminate their breeding ground. This could include clogged gutters, drains, puddles or other standing water. Look for items such as buckets or wheelbarrows that could collect water after a rain and remember to wash out and refill your birdbath every two days.

• Mosquito Control Controlling mosquitoes, and exposure to diseases they may carry, can be done by chemical and non-chemical methods.

• Illinois State Information on mosquitoes in the mid-west, as well as on West Nile disease and preventative measures.

• Mosquito fish  The introduction of the Western or Eastern species of the Gambusia – a mosquito eating fish.

Advice for Personal Protection

Over seven hundred million people annually are estimated to contract a mosquito transmitted disease and out of that number, around two million will die from them. The ideal situation would be the creation of a vaccine to prevent the disease, but until that happens, people must be vigilant. Prevent mosquito bites by using repellents and if living or traveling to areas prevalent to such disease, make sure to use nets and carry insecticides.

If you know you will be in an area where you might be susceptible to bites, wear light loose clothing that won’t allow a mosquito to come in contact with the skin and wear repellent. It is usually best to use a spray repellent that can be sprayed on your head as well, but be sure to protect your eyes when doing so. Without protection, avoid areas that are prone to mosquitoes, such as marshes, damp shaded areas and places like the woods. Follow these simple acts and help protect yourself from these disease-carrying bloodsuckers.

• Mosquito Bites A health page that offers links to information on mosquito bites and how to treat them.

• West Nile Virus Preventative measures to reduce your risk for WNV infections.

• Prevent Mosquito and Tick Bites  A print out page on steps to avoid bites.