Mosquito Diseases

Mosquito Diseases

Mosquito Diseases

Malaria

• Malaria is the most well-known mosquito-transmitted illness. 
• Malaria is spread by a particular type of mosquito (the infected Anopheles mosquito) found only in certain parts of the world. 
• People living in, or visiting, those places can reduce the risk of malaria by taking antimalarial tablets, and taking measures to avoid being bitten.

Dengue fever

• The mosquitoes that transmit dengue fever breed in containers that hold water, and bite during the day, not mainly at dusk or evening like other types of mosquito. 
• People infected with the virus may have no symptoms, but others may experience high fever, severe headache, muscle and joint pain, rash and extreme fatigue. 
• In rare cases, dengue fever can be severe and even fatal (dengue haemorrhagic fever). 
• It is important to seek immediate medical advice if you suspect you have dengue fever.
• There is no vaccine against dengue fever, so mosquito prevention measures are essential. The mosquito responsible (the infected Aedes mosquito) is found in many tropical and subtropical areas. 

Japanese encephalitis

• Japanese encephalitis is an infection of the brain caused by a virus that is spread by infected mosquitoes. 
• The mosquitoes become infected after biting pigs infected with the virus. Japanese encephalitis occurs in parts of Asia and Papua New Guinea. 
• There have also been cases in north Queensland in Australia. 
• Most infected people have no symptoms, but a small proportion may have severe symptoms, including headaches, high fever, convulsions and coma. 
• There is no treatment, but a vaccine is available to protect against the infection in people travelling to, or resident in, areas where the virus is found.

Ross River virus infection

• Occurring widely in Australia, the Ross River virus is spread from animals to humans by several different types of mosquitoes.
• Although many people infected with this virus have no symptoms or only slight symptoms, other people may have a fever, joint pain and swelling and a rash. 
• There is no specific treatment but medicines may be taken to help relieve the symptoms.

Barmah Forest virus infection

• The Barmah Forest virus is also widespread in Australia and causes a similar illness to Ross River virus infection but the symptoms usually last for a shorter length of time.
• The virus is spread from animals to humans by mosquitoes. 
• Again, there is no specific treatment for this infection, but medicines may be taken to help manage the symptoms.

Murray Valley encephalitis

• Murray Valley encephalitis is a very rare disease involving swelling of the brain tissue. 
• The disease is caused by infection with a virus that is spread by the bite of infected mosquitoes. 
• The mosquito responsible is found throughout Australia and breeds in surface pools of water. Water birds, such as herons, are a natural reservoir of the virus. 
• Most people infected with the Murray Valley encephalitis virus do not develop symptoms, but others may have high fever, severe headache, neck stiffness, irritability, seizures (or fits), and drowsiness. 
• Immediate medical advice should be sought for these symptoms.

Yellow fever

• Yellow fever occurs in areas such as Africa and South America, and is spread by infectedAedes and Haemogogus mosquitoes. 
• It can be spread by mosquitoes in jungle/rural areas as well as urban areas. 
• Yellow fever causes a flu-like illness, but some people develop a more severe form which can be life threatening. 
• The ‘yellow’ relates to jaundice which occurs as part of the severe illness. No specific treatment is available other than supportive measures.
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• For prevention, however, yellow fever vaccination is available and involves a single injection. The vaccine becomes effective after 10 days, and should last for 10 years.
• Yellow fever vaccine can only be given in approved vaccination centres, and some countries will require a certificate of vaccination below allowing you to enter. 
• Ask your travel medicine clinic to advise on whether this vaccine is recommended for your trip.

Reducing the risk of mosquito bites

Because there is no specific treatment for many of the mosquito-borne diseases, and few vaccines or medicines available to prevent them, the best protection is to avoid mosquito bites. 

Measures to avoid being bitten by mosquitoes include:

• Trying to stay indoors at dusk (when most mosquitoes do their biting)
• wearing light-coloured, long-sleeved shirts, long trousers and covered shoes at this time of the day (but note, dengue-carrying mosquitoes also bite during the day)
• using effective insect repellents (eg, DEET) when outdoors
• choosing accommodation that has air-conditioning or insect screens on rooms (otherwise, sleeping under a mosquito bed net, preferably pre-soaked in permethrin)
• using insect sprays inside
• if applicable, removing outside containers that hold water where mosquitoes might breed.