Controlling Mosquitoes

What you can do to control mosquitoes around the home

1. Remove their habitat (where they live and breed)
* Eliminate standing water in rain gutters, old tires, buckets, plastic covers, toys, or any other container where mosquitoes can breed.
* Empty and change the water in bird baths, fountains, wading pools, rain barrels, and potted plant trays at least once a week to destroy potential mosquito habitats.
* Drain or fill temporary pools of water with dirt.
* Keep swimming pool water treated and circulating.

2. Prevent your exposure to mosquitoes
* Use EPA-registered mosquito repellents when necessary and follow label directions and precautions closely.
* Use head nets, long sleeves and long pants if you venture into areas with high mosquito populations, such as salt marshes.
* If there is a mosquito-borne disease warning in effect, stay inside during the evening when mosquitoes are active.
* Make sure window and door screens are "bug tight."
* Replace your outdoor lights with yellow "bug" lights which tend to attract less mosquitoes than ordinary lights. The yellow lights are NOT repellents, however.

Neighborhoods are occasionally sprayed to prevent disease and nuisance caused by large mosquito numbers. If you have any questions about mosquitoes and their control, contact your local mosquito control district or health department.


Methods used by federal, state and local agencies in mosquito control.

Surveillance as First Step in Mosquito Control

The first step in mosquito control is surveillance. State or local mosquito specialists conduct surveillance for diseases harbored by domestic and nonnative birds, including sentinel chickens (used as virus transmission indicators), and mosquitoes. State and local mosquito control authorities also conduct surveillance for larval habitats by using maps and aerial photographs, and by evaluating larval populations. Other techniques include various light traps, biting counts, and analysis of reports from the public.

Mosquito control programs also put high priority on trying to prevent a large population of adult mosquitoes from developing so that additional controls may not be necessary. Since mosquitoes must have water to breed, methods of prevention may include:

* controlling water levels in lakes, marshes, ditches, or other mosquito breeding sites;
* eliminating small breeding sites if possible;
* stocking bodies of water with fish species that feed on larvae.

Both chemical and biological measures may be employed to kill immature mosquitoes during larval stages.

Chemical or Biological Measures to Control Mosquitoes

Controlling mosquitoes at the larval stage

Larvicides target larvae in the breeding habitat before they can mature into adult mosquitoes and disperse. Larvicides include:

Bacterial Insecticides

* Bacillus thuringiensis israelensis
* Bacillus sphaericus

Insect Growth Inhibitor

* Methoprene

Organophosphate Insecticide

* Temephos

Other Materials

* Mineral oils
* Monomolecular films

Oils and films disperse as a thin layer on the surface of the water which cause larvae and pupae to drown. Liquid larvicide products are applied directly to water using backpack sprayers and truck or aircraft-mounted sprayers. Tablet, pellet, granular, and briquet formulations of larvicides are also applied by mosquito controllers to breeding areas.

Controlling Adult Mosquitoes

Adult mosquito control may be undertaken to combat an outbreak of mosquito-borne disease or a very heavy nuisance infestation of mosquitoes in a community. Pesticides registered for this use are known as adulticides and are applied either by aircraft or on the ground employing truck-mounted sprayers. State and local agencies commonly use the organophosphate insecticides malathion and naled and the synthetic pyrethroid insecticides permethrin, resmethrin, and sumithrin for adult mosquito control.

Mosquito adulticides are applied as ultra-low volume (ULV) sprays. ULV sprayers dispense very fine aerosol droplets that stay aloft and kill flying mosquitoes on contact. ULV applications involve small quantities of pesticide active ingredient in relation to the size of the area treated, typically less than 3 ounces per acre, which minimizes exposure and risks to people and the environment.

Adulticides can be used for public health mosquito control programs without posing unreasonable risks to the general population or to the environment when applied according to the pesticide label. For more information on pesticides commonly-used in public health mosquito control programs, see the specific fact sheets mentioned below.

http://www.epa.gov/

Protection From Mosquitoes

Always remember the 3 D’s of protection from mosquitoes

Drain

Many mosquito problems in your neighborhood are likely to come from water-filled containers
that you, the resident, can help to eliminate. All mosquitoes require water in which to breed. Be
sure to drain any standing water around your house.
- Dispose of any tires. Tires can breed thousands of mosquitoes.
- Drill holes in the bottom of recycling containers.
- Clear roof gutters of debris.
- Clean pet water dishes regularly.
- Check and empty children’s toys.
- Repair leaky outdoor faucets.
- Change the water in bird baths at least once a week.
- Canoes and other boats should be turned over.
- Avoid water collecting on pool covers.
- Empty water collected in tarps around the yard or on woodpiles.
- Plug tree holes.
- Even the smallest of containers that can collect water can breed hundreds to thousands of mosquitoes.

They don't need much water to lay their eggs. (bottles, barrels, buckets, overturned garbage can
lids, etc.)


Dress

Wear light colored, loose fitting clothing. Some of the 176 mosquito species are attracted to dark
clothing and some can bite through tight-fitting clothes. When practical, wear long sleeves and
pants.


Defend

Choose a mosquito repellent that has been registered by the Environmental Protection Agency. Registered products have been reviewed, approved, and pose minimal risk for human safety when used according to label directions. Three repellents that are approved and recommended are:
- DEET (N,N-diethyl-m-toluamide)
- Picaridin (KBR 3023)
- Oil of lemon eucalyptus (p-methane 3,8-diol, or PMD)
Here are some rules to follow when using repellents:
- Read the directions on the label carefully before applying.
- Apply repellent sparingly, only to exposed skin (not on clothing).
- Keep repellents away from eyes, nostrils and lips: do not inhale or ingest repellents or get them into the eyes.
- The American Academy of Pediatrics suggests that DEET-based repellents can be used on children as young as two months of age. Generally, the AAP recommends concentrations of 30% or less.
- Avoid applying repellents to portions of children's hands that are likely to have contact with eyes or mouth.
- Pregnant and nursing women should minimize use of repellents.
- Never use repellents on wounds or irritated skin.
- Use repellent sparingly and reapply as needed. Saturation does not increase efficacy.
- Wash repellent-treated skin after coming indoors.
- If a suspected reaction to insect repellents occurs, wash treated skin, and call a physician. Take the repellent container to the physician.

http://www.mosquito.org/pdfs/Mosquito-Prevention-Facts.pdf

MOSQUITO !!!

Mosquitoes are insects belonging to the order Diptera, the True Flies. Like all True Flies, they have two wings, but unlike other flies, mosquito wings have scales. Female mosquitoes' mouthparts form a long piercing-sucking proboscis. Males differ from females by having feathery antennae and mouthparts not suitable for piercing skin. A mosquito's principal food is nectar or similar sugar source.

There are over 2500 different species of mosquitoes throughout the world; about 200 species occur in the United States with 77 species occurring in Florida. A new species, Anopheles grabhamii, was reported from the Florida Keys in 2001 (Darsie et al. 2002). Each mosquito species has a Latin scientific name, such as Anopheles quadrimaculatus. Anopheles is the "generic" name of a group of closely related mosquitoes and quadrimaculatus is the "species" name that represents a group of individuals that are similar in structure and physiology and capable of interbreeding. These names are used in a descriptive manner so that the name tells something about each particular mosquito, for example, Anopheles - Greek meaning hurtful or prejudicial and quadrimaculatus - Latin meaning four spots (4 dark spots on the wings). Some species have what are called "common names" as well as scientific names, such as Ochlerotatus taeniorhynchus, the "black salt marsh mosquito."

Scientific investigators (taxonomists) are constantly looking for new mosquitoes, as well as reviewing previously identified specimens for new information or identifying characteristics. Better microscopic equipment developed in the last 20 years has improved the taxonomist's ability to determine differences between species. Recently such a review by Dr. John Reinert (2000) led to a change in the name of many mosquitoes belonging to the genus Aedes. Using improved methods and over 30 years' experience he elevated a subgenus of Aedes ( Ochlerotatus ) to the status of genus. This will necessitate the renaming of many mosquitoes previously named Aedes to the genus Ochlerotatus and the rewriting of many taxonomic keys important to public health entomologists working in mosquito control.
The Name "Mosquito"

The Spanish called the mosquitoes "musketas," and the native Hispanic Americans called them "zancudos." "Mosquito" is a Spanish or Portuguese word meaning "little fly" while "zancudos," a Spanish word, means "long-legged." The use of the word "mosquito" is apparently of North American origin and dates back to about 1583 (http://www.mda.state.md.us/mosquito/mosquito.htm). In Europe, mosquitoes were called "gnats" by the English, "Les moucherons" or "Les cousins" by French writers, while the Germans used the name "Stechmucken" or "Schnacke." In Scandinavian countries mosquitoes were called by a variety of names including "myg" and "myyga" and the Greeks called them "konopus." In 300 B.C., Aristotle referred to mosquitoes as "empis" in his "Historia Animalium" where he documented their life cycle and metamorphic abilities. Modern writers used the name Culex and it is retained today as the name of a mosquito genus. What is the correct plural form of the word mosquito? In Spanish it would be "mosquitos," but in English "mosquitoes" (with the "e") is correct.

Mosquitoes can be an annoying, serious problem in man's domain. They interfere with work and spoil hours of leisure time. Their attacks on farm animals can cause loss of weight and decreased milk production. Some mosquitoes are capable of transmitting diseases such as malaria, yellow fever, dengue, filariasis and encephalitis [St. Louis encephalitis (SLE), Western Equine encephalitis (WEE), LaCrosse encephalitis (LAC), Japanese encephalitis (JE), Eastern Equine encephalitis (EEE) and West Nile virus (WNV)] to humans and animals.

By Tom Floore
Public Health Entomology Research & Education Center
Florida Agricultural & Mechanical University

Dengue

Dengue is transmitted by the bite of an Aedes mosquito infected with any one of the four dengue viruses. It occurs in tropical and sub-tropical areas of the world. Symptoms appear 3—14 days after the infective bite. Dengue fever is a febrile illness that affects infants, young children and adults.

Symptoms range from a mild fever, to incapacitating high fever, with severe headache, pain behind the eyes, muscle and joint pain, and rash. There are no specific antiviral medicines for dengue. It is important to maintain hydration. Use of acetylsalicylic acid (e.g. aspirin) and non steroidal anti-inflammatory drugs (e.g. Ibuprofen) is not recommended.

Dengue haemorrhagic fever (fever, abdominal pain, vomiting, bleeding) is a potentially lethal complication, affecting mainly children. Early clinical diagnosis and careful clinical management by experienced physicians and nurses increase survival of patients.

Dengue/dengue haemorrhagic fever

Dengue is the most common mosquito-borne viral disease of humans that in recent years has become a major international public health concern. Globally, 2.5 billion people live in areas where dengue viruses can be transmitted. The geographical spread of both the mosquito vectors and the viruses has led to the global resurgence of epidemic dengue fever and emergence of dengue hemorrhagic fever (dengue/DHF) in the past 25 years with the development of hyperendemicity in many urban centers of the tropics.

Transmitted by the main vector, the Aedes aegytpi mosquito, there are four distinct, but closely related, viruses that cause dengue. Recovery from infection by one provides lifelong immunity against that serotype but confers only partial and transient protection against subsequent infection by the other three. There is good evidence that sequential infection increases the risk of more serious disease resulting in DHF.

DHF was first recognized in the 1950s during the dengue epidemics in the Philippines and Thailand. By 1970 nine countries had experienced epidemic DHF and now, the number has increased more than fourfold and continues to rise. Today emerging DHF cases are causing increased dengue epidemics in the Americas, and in Asia, where all four dengue viruses are endemic, DHF has become a leading cause of hospitalization and death among children in several countries.

Currently vector control is the available method for the dengue and DHF prevention and control but research on dengue vaccines for public health use is in process. The global strategy for dengue /DHF prevention and control developed by WHO and the regional strategy formulation in the Americas, South-East Asia and the Western Pacific during the 1990s have facilitated identification of the main priorities: strengthening epidemiological surveillance through the implementation of DengueNet; accelerated training and the adoption of WHO standard clinical management guidelines for DHF; promoting behavioral change at individual, household and community levels to improve prevention and control; and accelerating research on vaccine development, host-pathogen interactions, and development of tools/interventions by including dengue in the disease portfolio of TDR (UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases) and IVR (WHO Initiative for Vaccine Research).

Malaria

Malaria is caused by a parasite called Plasmodium, which is transmitted via the bites of infected mosquitoes. In the human body, the parasites multiply in the liver, and then infect red blood cells.

Symptoms of malaria include fever, headache, and vomiting, and usually appear between 10 and 15 days after the mosquito bite. If not treated, malaria can quickly become life-threatening by disrupting the blood supply to vital organs. In many parts of the world, the parasites have developed resistance to a number of malaria medicines.

Key interventions to control malaria include: prompt and effective treatment with artemisinin-based combination therapies; use of insecticidal nets by people at risk; and indoor residual spraying with insecticide to control the vector mosquitoes.

Infection and transmission

Malaria is a disease which can be transmitted to people of all ages. It is caused by parasites of the species Plasmodium that are spread from person to person through the bites of infected mosquitoes. The common first symptoms – fever, headache, chills, and vomiting – appear 10 to 15 days after a person is infected. If not treated promptly with effective medicines, malaria can cause severe illness that is often fatal.

There are four types of human malaria – Plasmodium falciparum, P.vivax, P.malariae, and P.ovale. P.falciparum and P.vivax are the most common. P.falciparum is by far the most deadly type of malaria infection.

Malaria transmission differs in intensity and regularity depending on local factors such as rainfall patterns, proximity of mosquito breeding sites and mosquito species. Some regions have a fairly constant number of cases throughout the year – these are malaria endemic – whereas in other areas there are “malaria” seasons, usually coinciding with the rainy season.

Large and devastating epidemics can occur in areas where people have had little contact with the malaria parasite, and therefore have little or no immunity. These epidemics can be triggered by weather conditions and further aggravated by complex emergencies or natural disasters.

Global and regional risk

Approximately, 40% of the world’s population, mostly those living in the world’s poorest countries, are at risk of malaria. Every year, more than 500 million people become severely ill with malaria. Most cases and deaths are in sub-Saharan Africa. However, Asia, Latin America, the Middle East and parts of Europe are also affected. Travellers from malaria-free regions going to areas where there is malaria transmission are highly vulnerable – they have little or no immunity and are often exposed to delayed or wrong malaria diagnosis when returning to their home country.

Treatment

Early diagnosis and prompt treatment are the basic elements of malaria control. Early and effective treatment of malaria disease will shorten its duration and prevent the development of complications and the great majority of deaths from malaria. Access to disease management should be seen not only as a component of malaria control but a fundamental right of all populations at risk. Malaria control must be an essential part of health care development. In contemporary control, treatment is provided to cure patients rather than to reduce parasite reservoirs.

Antimalarial treatment policies will vary between countries depending on the epidemiology of the disease, transmission, patterns of drug resistance and political and economic contexts.

Drug resistance

The rapid spread of antimalarial drug resistance over the past few decades has required more intensive monitoring of drug resistance to ensure proper management of clinical cases and early detection of changing patterns of resistance so that national malaria treatment policies can be revised where necessary. Surveillance of therapeutic efficacy over time is an essential component of malaria control. Recent efforts to scale-up malaria control in endemic countries throughout the world including increased support for commodities and health systems, as well as the proposed price subsidy on artemisinin-based combination therapies (ACTs) is resulting in greater access to and a vastly increased use of antimalarial medicines, in particular ACTs. This is leading to a much higher degree of drug pressure on the parasite which will almost certainly increase the likelihood of selecting for resistant parasite genotypes. There are currently no effective alternatives to artemisinins for the treatment of P. falciparum malaria either on the market or towards the end of the development pipeline.

The parasite's resistance to medicines continues to undermine malaria control efforts. WHO has therefore called for continuous monitoring of the efficacy of recently implemented ACTs, and countries are being assisted in strengthening their drug resistance surveillance systems. In order to preserve the efficacy of artemisinins as an essential component of life-saving ACTs, WHO has called for a ban on the use of oral artemisinin monotherapies, at various levels, including manufacturers, international drug suppliers, national health authorities and international aid and funding agencies involved in the funding of essential antimalarial medicines.

Prevention: vector control and intermittent preventive therapy in pregnant women

The main objective of malaria vector control is to significantly reduce both the number and rate of parasite infection and clinical malaria by controlling the malaria-bearing mosquito and thereby reducing and/or interrupting transmission. There are two main operational interventions for malaria vector control currently available: Indoor Residual Spraying of long-acting insecticide (IRS) and Long-Lasting Insecticidal Nets (LLINs). These core interventions can be locally complemented by other methods (e.g. larval control or environmental management) in the context of Integrated Vector Management (IVM). Effective and sustained implementation of malaria vector control interventions (IRS or LLINs) requires clear political commitment and engagement from national authorities as well as long-term support from funding partners.

Pregnant women are at high risk of malaria. Non-immune pregnant women risk both acute and severe clinical disease, resulting in up to 60% fetal loss and over 10% maternal deaths, including 50% mortality for severe disease. Semi-immune pregnant women with malaria infection risk severe anaemia and impaired fetal growth, even if they show no signs of acute clinical disease. An estimated 10 000 of these women and 200 000 of their infants die annually as a result of malaria infection during pregnancy. HIV-infected pregnant women are at increased risk. WHO recommends that all endemic countries provide a package of interventions for prevention and management of malaria in pregnancy, consisting of (1) diagnosis and treatment for all episodes of clinical disease and anaemia and (2) insecticide-treated nets for night-time prevention of mosquito bites and infection. In highly endemic falciparum malaria areas, this should be complemented by (3) intermittent preventive treatment with sulfadoxine–pyrimethamine (IPT/SP) to clear the placenta periodically of parasites.

Insecticide resistance

In spite of increased national and international efforts to scale up cost-effective malaria vector control interventions and maximize the protection of populations at risk, significant challenges continue to threaten these objectives and the sustainability of achievements. Challenges include increasing resistance of vector mosquitoes to insecticides, the behaviour and ecology of local malaria vectors – which often change as a result of vector control interventions -- and the diminishing number of available insecticides that can be used against malaria vectors (adulticides).

There are currently no alternatives to DDT and pyrethroids and the development of new insecticides will be an expensive long-term endeavour. Therefore, immediate sound vector resistance management practices are required to assure the continued utility of the currently available insecticides. At present there is only limited evidence of the impact of various resistance mechanisms on the efficacy of vector control interventions, whether they are implemented singly or in combination.

Recent evidence from Africa indicates that pyrethroid and DDT resistance is more widespread than anticipated. It is believed that the same level of resistance will have a more detrimental impact on the efficacy of IRS than on that of LLINs, but evidence for this is very limited. Networks for vector resistance monitoring still need greater strengthening in order to make resistance detection a routine operational feature of national programmes, particularly in countries in Africa and the Eastern Mediterranean region. Regional level databases feeding into a global database accessible by governments, scientists and policy-makers would greatly assist in the rational use and deployment of vector control interventions.

Socioeconomic impact

Malaria causes an average loss of 1.3% annual economic growth in countries with intense transmission. When compounded over the years, this loss has lead to substantial differences in GDP between countries with and without malaria. Malaria traps families and communities in a downward spiral of poverty, disproportionately affecting marginalized populations and poor people who cannot afford treatment or who have limited access to health care. Malaria’s direct costs include a combination of personal and public expenditures on both prevention and treatment of disease. In some countries with a very heavy malaria burden, the disease may account for as much as 40% of public health expenditure, 30-50% of inpatient admissions and up to 60% of outpatient visits. Malaria has lifelong effects through increased poverty, impaired learning and decreases attendance in schools and the workplace.