Mosquito borne infections

Mosquito borne infections - What it is

Besides causing red and itchy bites, mosquitoes can spread many human diseases including:

* Dengue virus: Occur in Asia (including Singapore), Central and South America, the Caribbean, Western Pacific Islands, Australia, and Africa. It can also cause serious outbreaks (https://wwwnc.cdc.gov/travel/diseases/dengue).

* Chikungunya virus: occurs in Asia (including Singapore), Central and South America, the Caribbean, Western and South Pacific, and Africa (https://wwwnc.cdc.gov/travel/diseases/chikungunya#).

* Zika virus: occurs in Asia (including Singapore), North, South and Central America, the Caribbean, Pacific Islands, and Africa (https://wwwnc.cdc.gov/travel/page/zika-information).

* Yellow fever virus: Occurs in South America, Central America and Africa (https://wwwnc.cdc.gov/travel/diseases/yellow-fever).

* West Nile virus: Occurs in Africa, Europe, the Middle East, west and central Asia or North America (https://wwwnc.cdc.gov/travel/diseases/west-nile-virus).

* Malaria: Occurs in Asia, Africa, Central and South America, parts of the Caribbean, Eastern Europe, and the South Pacific. Malaria can be particularly severe in people without prior exposure to the disease (https://wwwnc.cdc.gov/travel/diseases/malaria).

* Japanese encephalitis: Occurs in Asia and parts of the western Pacific (https://www.cdc.gov/japaneseencephalitis/index.html).

Mosquito borne infections - Symptoms

Most people do not become sick after a mosquito bite; the most common reaction is local reaction with rash and itch. However, as mentioned above, infections can be transmitted from mosquitoes. Some people may develop mild and short-term illnesses. Rarely, some infections can result in severe illness and death. Mosquito bite marks are not always evident.

Common symptoms of mosquito bite infections include:

Fever
Skin rash
Bone, joint, or eye pain
Headache
Loss of appetite
Vomiting
Red eyes

Other more severe symptoms, depending on the type of infection include:

Bleeding from nose, gum, skin, vomit and urine
Persistent vomiting
Diarrhoea
Severe abdominal pain
Shortness of breath
Fatigue or restlessness
Reduced consciousness or confusion
Cold or clammy extremities
Dehydration – decreased urination, dry mouth or lips, light-headedness

For pregnant women, Zika infection during pregnancy has been associated with birth defects.

If you develop severe symptoms and suspect a mosquito borne infection, you should visit your doctor right away.

Mosquito borne infections - How to prevent?

People at risk

People are at risk when they are travelling to places where mosquitoes are breeding. Different species of mosquitoes are active during different times of the day and are found in different geographic locations. The type of mosquito borne infections acquired is also dependent on travel and exposure history.

Prevention

In tropical countries including Singapore, mosquitoes are active year-round. Mosquitoes may bite during the day or evening, both indoors and outdoors depending on the species. The best way to prevent the illnesses they spread is to:

Prevent mosquito bites

Apply mosquito repellent to exposed skin. Always follow the product label instructions and reapply as directed.
Do not apply repellent on cuts, wounds on irritated skin.
If you are also using sunscreen, apply sunscreen before insect repellent.
Do not apply repellent near the eyes or mouth, and apply sparingly around ears.
When using spray repellent, do not spray directly on the face. Spray it on the hands first and then apply it to the face.
Wear light-coloured, long-sleeved clothing to reduce exposed skin.
Stay in accommodations that are air conditioned or use window screens.
Sleep under mosquito nets.

Prevent mosquito breeding inside and outside your home

Change water in vases and bowls on alternate days.
Remove water from flower pot plates on alternate days. Clean and scrub the plate thoroughly to remove mosquito eggs.
Turn over water storage containers. This prevents water from collecting inside.
Loosen soil from potted plants to prevent the accumulation of stagnant water on the surface of the hardened soil.
Clear blockages to prevent build-up of stagnant water, and put Bacillus thuringiensis (BTI) insecticide in roof gutters monthly.

Protect yourself from mosquito-borne infections while traveling

If you are traveling, consult a healthcare provider familiar with travel medicine, even if you are well. You should visit early, ideally 4 – 6 weeks before your trip (link to travel clinic). Your doctor can advise you on measures which can be taken to avoid infectious diseases to which you may be exposed while overseas. These measure may include vaccinations, medications to reduce the risk of acquiring infections, or measures to reduce exposure.
Check about country-specific risks and recommendations by visiting CDC traveller’s health website (http://wwwnc.cdc.gov/travel)

Vaccination

Vaccines against Yellow Fever, Japanese encephalitis, and dengue are currently licensed and available in Singapore. You should consult your doctor for advice on vaccination.

Mosquito borne infections - Diagnosis

Diagnosis of mosquito-borne infections can sometimes be difficult, because symptoms can be easily confused with those of other diseases.

Your doctor will likely ask about your medical symptoms and travel history in detail, including the countries you visited and the dates, as well as any contact you may have with mosquitoes.

Certain laboratory tests can be performed on blood, urine and other body fluid specimens (depending on the type of infection) to detect evidence of mosquito-borne infections.

Mosquito borne infections - Treatments

With the exception of malaria, no specific treatment exists for most mosquito-borne infections, symptomatic treatment and supportive care is mainstay of therapy.

Your doctor may recommend that you drink plenty of fluids to avoid dehydration from fever, poor appetite, vomiting and diarrhoea. You may be advised to rest

Paracetamol may reduce fever and alleviate pain. In general, pain relievers that can cause increased bleeding – such as aspirin, ibuprofen, and diclofenac should be avoided.

If you have malaria or severe infection, you may require care in a hospital for closer monitoring. In addition, intravenous medications and fluids may be required.