It's safe to say that mosquitos are one of the least-loved insects on the planet. They bite, ruin outdoor activities, and in rare cases, can spread viruses that can cause serious illness.
This summer, Australian residents in NSW, VIC and SA in particular are encouraged to try to protect themselves against mosquito bites following the detection of viruses in people and mosquitos including Murray Valley encephalitis (MVE) virus, Japanese encephalitis virus (JEV), Ross River virus and Barmah Forest virus.
The uptick in virus cases is due to a wet spring followed by a warm summer, providing perfect conditions for the flying pests. Health authorities are particularly concerned about MVE, JEV and Kujin Virus which can be fatal because they may cause brain swelling. Read on to find out more about the various diseases you may catch from mosquito bites and how to diagnose and treat them.
It is important to note that while serious, many of the diseases here are very rare in Australia and New Zealand. If you or a family member is experiencing painful mosquito bites without other symptoms, get first aid advice here.
Types of mosquito-borne diseases
MURRAY VALLEY ENCEPHALITIS
What is it? A rare but serious virus that is spread through the bite of MVE-positive mosquitoes.
Where? Northern Australia and Papa New Guinea.
Mild symptoms: fever, headache, nausea and vomiting.
Severe symptoms: drowsiness, confusion, shaking, neck stiffness and seizures.
Symptoms onset: typically symptoms begin 7-12 days post-initial bite from an infected mosquito. However, it can also be as little as 5 days or as long as 28 days after the initial bite.
Diagnosis: MVE can be determined through a number of medical investigations including; blood tests, MRI/CT of the brain, lumbar puncture and microbiology testing (eg: nose/throat swabs, urine or faeces collection). You should see your doctor urgently to determine a diagnosis.
Treatment: once diagnosed with MVE your treating clinician will determine the next step to take. The treatment plan will be dependent on the progression and severity of the virus. Mild symptoms usually are closely monitored and given medications to treat the side effects of the virus and pain management for comfort. Whereas, more severe symptoms will have more intensive treatment depending on how the virus is taking effect on the individual.
Prevention: avoid being bitten by mosquitoes by covering up your skin as much as possible; use insect repellent and use fly screens or mosquito nets where possible.
ROSS RIVER VIRUS
What is it? An infection spread to humans through infected mosquitoes.
Where? Anywhere in Australia but mostly in Qld, WA and the NT.
Common symptoms: Fevers, joint pain, rash to the arms/legs, headaches, fatigue, and swollen lymph nodes.
Symptom onset: If symptoms are to occur it can range from 3 days to 3 weeks post initial bite from an infected mosquito.
Diagnosis: Should you be experiencing symptoms a GP may do a blood test to rule out other causes for these symptoms. However, a diagnosis of Ross River Virus would not change the management of your symptoms.
Treatment: There is no medical intervention to treat this and although it is not life-threatening it can be uncomfortable therefore, paracetamol and anti-inflammatory medicines can relieve discomfort.
Prevention: Stay indoors at dusk and dawn; use insect repellent; wear long-sleeved clothing; use mosquito coils/lanterns as well as fly screens and mosquito nets.
BARMAH FOREST VIRUS
What is it? An illness transmitted by mosquitoes from animals to humans.
Where? It is only found in Australia, throughout most regions, particularly around inland waterways and coastal regions.
Symptoms: Fevers, chills, headaches, tiredness, joint pain and swelling, muscle tenderness, rashes on the torso or limbs, and swollen lymph nodes.
Symptom onset: Usually occurs 7-10 days after being bitten by an infected mosquito, however, most people present with no symptoms.
Diagnosis: If you have symptoms your GP may do a blood test to confirm if you have the virus.
Treatment: There is no medical intervention required to treat the virus however, other medication may be prescribed to help relieve the cause of the symptoms.
Prevention: Stay indoors at dusk and dawn; use insect repellent; wear long-sleeved clothing; use mosquito coils/lanterns as well as fly screens and mosquito nets.
DENGUE FEVER
What is it? a fever that may present very similarly to the flu, caused by being bitten by an infected mosquito. In more serious presentations individuals can go on to develop bleeding that can be life-threatening.
Where? tropical and sub-tropical places like Africa, Asia and South America.
Mild Symptoms: fever, headache, pain behind the eyes, muscle/joint pain, nausea, vomiting, swollen glands, rash, sensitive gums, and fatigue.
Severe symptoms: Unexplained bruising, bleeding from the nose/gums, stomach pain, breathing difficulties, bloody or black poo, cold and clammy skin.
Symptom onset: Usually occurs 3-14 days after post being bitten by an infected mosquito.
Diagnosis: Usually occurs 3-14 days after post being bitten by an infected mosquito.
Treatment: If you have severe symptoms you should seek medical assistance without delay. There is no treatment for dengue fever however, you may be prescribed medications to help relieve your symptoms. You should avoid non-steroidal anti-inflammatories such as ibuprofen until dengue fever is ruled out.
Prevention: People who have had dengue fever in the past are more at risk of becoming unwell if infected again therefore its recommended that you stay indoors at dusk and dawn; use insect repellent; wear long-sleeved clothing; use mosquito coils/lanterns as well as fly screens and mosquito nets.
CHIKUNGUNYA VIRUS
What is it? A virus spread to humans through infected mosquitoes.
Where? Australia, Southeast Asia, Africa and also the Western Pacific.
Symptoms: muscle pain, headaches, a rash on your torso and/or limbs, nausea, fatigue.
Symptom onset: Usually appear 3-7 days after being bitten but they can take up to 12 days to develop.
Risk factors: Over 65-year-olds, newborn babies people with high blood pressure, diabetes, or heart disease can be more at risk of becoming unwell.
Diagnosis: If you have symptoms your doctor can perform a medical assessment alongside a blood test.
Treatment: There is no treatment for Chikungunya virus however, you may be prescribed medications to help relieve your symptoms. You should avoid non-steroidal anti-inflammatories such as ibuprofen as Chikungunya and dengue fever present similarly.
Prevention: stay indoors at dusk and dawn; use insect repellent; wear long-sleeved clothing; use mosquito coils/lanterns as well as fly screens and mosquito nets.
YELLOW FEVER:
What is it? A virus that is spread to humans through infected mosquitoes.
Where? Not found in Australia, but it is in Africa, and Central and South America - be alert if you have travelled to any of these areas.
Initial symptoms: Fever, chills, body aches, back pain, nausea, vomiting, severe headache, fatigue, or weakness.
Severe symptoms: High fever (above 39.4 degrees), jaundice, bleeding, shock, and organ failure (once presenting with organ failure, chances of mortality within 10-14 days increase by 50%).
Symptom onset: Usually occurs 3-6 days after being bitten by an infected mosquito.
Diagnosis: Can be determined from a medical assessment alongside a blood test.
Treatment: If you have severe symptoms you should seek medical attention straight away. There is no treatment for yellow however, you may take paracetamol to help with the pain and fevers. It is important to stay hydrated throughout. You should avoid non-steroidal anti-inflammatories such as ibuprofen until dengue fever is ruled out.
Prevention: There is a vaccination if you are travelling to higher-risk countries. You should stay indoors at dusk and dawn; use insect repellent; wear long-sleeved clothing; use mosquito coils/lanterns as well as fly screens and mosquito nets.
KUNJIN VIRUS:
What is it? A virus spread when a mosquito bites an infected animal and then the mosquito goes on to bite a person.
Where? Parts of Australia, Africa, Europe, the Middle East and the USA.
Symptoms: Fever, enlarged lymph nodes, rash, swollen and aching joints, headaches, fatigue, and muscle weakness.
Symptom onset: Can occur 7-28 days after being bitten by an infected mosquito. Most people, however, never display symptoms.
Diagnosis: Can be determined from a medical assessment alongside a blood test.
Treatment: If you have severe symptoms and have been exposed to areas known to have Kunjin Virus you should seek medical attention straight away. There is no treatment for the virus however, your medical professional can advise you on treatment to manage your symptoms.
Prevention: Stay indoors at dusk and dawn; use insect repellent; wear long-sleeved clothing; use mosquito coils/lanterns as well as fly screens and mosquito nets.
ZIKA VIRUS:
What is it? A virus mainly transmitted through mosquito bites. It can also be transmitted sexually or passed from an infected pregnant woman to her foetus.
Where? Central/South America, Africa, Asia, the Caribbean, Mexico and Pacific Islands.
Symptoms: Fever, rash, severe headache, joint pain, conjunctivitis or muscle pain. Symptoms are normally not severe and only last a few days, however, infection during pregnancy can cause a birth defect called microcephaly and other severe foetal brain defects. Rarely, Zika may cause Guillain-Barré syndrome, an uncommon sickness of the nervous system in which a person’s own immune system damages the nerve cells, causing muscle weakness, and sometimes, paralysis.
Risk factors: People who are pregnant or are planning to become pregnant should take extra precautions if travelling to an area with ongoing outbreaks.
Symptom onset: Usually occurs 3-12 days after post being bitten by an infected mosquito. Symptoms are only present in 1 out of 5 people.
Diagnosis: Can be determined from a medical assessment alongside a blood and urine test.
Treatment: If you are pregnant and are presenting with symptoms you should seek medical attention. There is no treatment for the virus however, your medical professional can advise you on treatment to manage your symptoms. Panadol can be taken for pain/fevers and it is important to stay hydrated.
Prevention: Avoid high-risk areas whilst pregnant. Taking safe sex precautions. Stay indoors at dusk and dawn; use insect repellent; wear long-sleeved clothing; use mosquito coils/lanterns as well as fly screens and mosquito nets.
MALARIA:
What is it? A serious and sometimes fatal disease caused by a parasite that commonly infects a certain type of mosquito that feeds on humans.
Where? Malaria can be found in large areas of Africa and Asia, Central and South America, the Dominican Republic and Haiti, parts of the Middle East and some Pacific islands.
Symptoms: Fever and flu-like symptoms, including shaking chills, headache, muscle aches and tiredness. Nausea, vomiting, and diarrhoea may also occur.
Severe symptoms: Seizures, confusion, Anemia, jaundice (yellow colouring of the skin and eyes) this is due to the loss of red blood cells. Malaria can be fatal, particularly when caused by the "plasmodium species" common in Africa. Malaria deaths are usually related to malaria progressing causing cerebral malaria - causing your brain to swell, or organ failure.
Risk factors: young children and infants, older adults, areas known to have malaria, pregnant women and their unborn child/s are more at risk of developing malaria if exposed.
Symptom onset: Usually occurs 6-30 days after being bitten by an infected mosquito. In rare cases, symptoms can take up to a year to present.
Diagnosis: Can be determined from a medical assessment alongside a blood test however, in some cases you may be referred to a doctor that specialises in infectious diseases.
Treatment: Malaria is treated with prescription drugs to kill the parasite. The type of the drug and the length of treatment will vary depending on your treating clinician.
Prevention: You can take antimalarial medicines prior to, during, and post travelling to areas where malaria is present. Stay indoors at dusk and dawn; use insect repellent; wear long-sleeved clothing; use mosquito coils/lanterns as well as fly screens and mosquito nets.
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Information sourced from: Healthdirect, CDC, and Better Health Channel.
Image credit: Picture Syed Ali, Unsplash.
All content is created and published for informational purposes only. It is not intended to be a substitute for professional advice. Always seek the guidance of a qualified health professional.