Trapping for mosquitoes usually occurs once every two weeks throughout the summer months.  The frequency of trapping is largely dependant on the weather conditions.  When setting mosquito traps random locations are selected around town. These are usually in peoples yards were there are cool dark places that are protected from the wind or street lights.

When traps are collected the mosquitoes are counted and identified because not all mosquitoes are responsible for transmitting disease.  Generally a threshold of around 50 mosquitoes per trap has been established and depending on what sort of species are identified a control method can be established.  The method of control chosen is entirely dependent on the situation, and in large rainfall events more than one type of control method may be warranted.

QUEENSLAND HEALTH 
Guidelines for Controlling Public Health Risks relating to Mosquitoes, Flies and Black Flies in a Flood Event - 28 January 2011. Click here for more information.

CONTROL MEASURES CURRENTLY BEING USED

Bifenthrin 

Bifenthrin is used by applying the chemical to areas where mosquitoes rest and also by providing a barrier between areas of human habitation and mosquito breeding areas.  It is most commonly applied to parks and gardens, and is also used to control mosquitoes around the home if mosquito numbers are very high.  It has up to a six week residual effect.

Fogging/misting with Reslin or Twilight

When there has been widespread rainfall and the source of mosquito breeding cannot be found, or there are large areas of low level mosquito breeding then it may be necessary to fog or mist with Reslin.  This is applied using a registered pest control operator and is done at times of the day when mosquitoes are most active, this is most commonly dawn and dusk.  Applying this chemical controls the adult mosquitoes that are flying around at the time and has no residual effect on the mosquitoes.  If mosquitoes are really bad, this control method is often used in conjunction with other mosquito control methods.

Prolink Briquettes

The active ingredient of Prolink is methoprene.  It is a growth hormone that is used to control mosquito larvae in smaller pools of water. It is specific to mosquito larvae and has little effect on other life in the water.  Prolink also comes in pellet form that is available for controlling mosquito larvae around the home eg in birdbaths or roof guttering. 

Liquid vectolex

Liquid Vectolex is a biological control method that is effective at killing mosquito larvae.  After there has been widespread rain, pools of water are sampled for mosquito breeding.  If there are large numbers of larvae depending on the species, liquid Vectolex will be used to control the larvae.  It has the advantage of being specific to mosquito larvae and is inert to animals or other living things in the water. 

Even though Council does its best to control mosquitoes there is plenty that you can do at home to reduce the spread of disease and to reduce mosquitoes breeding.

• make sure that your fly screens are in good order and tight fitting
• have your dog checked for heartworm and use preventative medication
• give your dog a protected place to sleep
• Stay indoors at dawn and dusk
• Use a reliable repellent- make sure that it contains DEET
• Clean up tins, containers, empty buckets, bins and old tyres left lying around your yard as they often contain water.
• Drain low lying areas that allow water to collect for longer than a week
• Report any mosquito breeding to council
• If mosquitoes are a problem contact your local pest controller, as an application of Bifenthrin may be an option.

MOSQUITO CONTROL FOLLOWING THE 2010 FLOOD
In December 2010, Emerald experienced a large amount of rainfall followed by widespread flooding.  This resulted in conditions that were ideal for prolific mosquito breeding.  The fogging program continued for three weeks after the event to control the adult mosquito and sandfly numbers.  Trapping and monitoring of mosquitoes is continuing.

DISEASES
There are two main viruses that are transmitted by mosquitoes in Emerald.  Both are transmitted by the mosquitoes Aedes notoscriptus and Culex annulirostris.

Ross River Virus (Epidemic Polyarthritis)

This is the most common arbovirus disease in Australia.  As many as 60% of people who become infected with the virus do not show any symptoms of the disease.  Once a person has had the disease they have long term immunity to it. The disease is most commonly observed in adults.  The symptoms include:

• Joint pain, primarily the wrist, knee, ankle, and small joints of the extremities.  Severe pain lasts 2-6 weeks with residual pain commonly lasting 30-40 weeks.  Relapses of severe pain are common during this 30-40 week interval.
• In many cases, the onset of arthritis is followed in 1-10 days by a rash, affecting mainly the trunk and limbs.  The rash disappears within 5-10 days.
• About 30-50% of people experience mild fever or chills.

The arthritis, rash and fever may occur in any sequence, and recovery from the disease may be associated with fatigue and depression.

Barmah Forest Virus

Barmah Forest virus is similar to Ross River Virus in that mosquitoes are responsible for its transmission.  It also usually causes an infection that is asymptomatic.  Clinical infection resembles Ross River virus, however it is less common with about 0.23% of the Queensland population being infected annually.

Mosquitoes are also responsible for a number of other diseases that are thankfully not a concern in Emerald.  More information can be found at www.health.qld.gov.au.  Just do a search on the word mosquito.

Ross River and Barmah Forest Statistics 09/10