Up to 400 million people are infected each year in tropical or sub-tropical countries around the world. In New Zealand, 161 cases of dengue fever were reported in 2017, all of which were contracted overseas.
Dengue fever has never been acquired in New Zealand, as New Zealand does not have the variety of mosquito that carries the virus. However, it is one of a number of nasty travel diseases that New Zealanders should take precautions to avoid.
Transmission of the virus
The incubation period (the time between infection with the virus and appearance of symptoms) is, on average, five to eight days.
The onset of symptoms is usually sudden and initial symptoms commonly include:
- High fever (up to 40°C)
- Rash (red with dots and blotches)
- Pain in the muscles and joints - particularly in the legs
- Pain behind the eyes - particularly when moving them
- Nausea and vomiting
- Red eyes
- Enlarged lymph nodes
- A red flush to the face
- Lower back pain
- Severe weakness and fatigue.
After infection with one of the four strains of dengue fever, the body is immune to that strain of the virus, and temporarily immune to the other strains for about a year. Subsequent infection with one of the other dengue fever strains tends to produce more severe symptoms than initial infections.
People who have previously been infected with dengue fever are at an increased risk of developing severe dengue if they contract the virus again.
Because dengue fever can be confused with other conditions such as influenza, measles, malaria, or typhoid fever, the doctor is likely to take blood tests in order to definitively diagnose the condition.
Treatment will aim to reduce the severity of symptoms:
- Adequate fluid intake to prevent dehydration due to vomiting and fever
- Pain-relieving medications such as paracetamol, which can help to relieve discomfort and to reduce the fever. Non-steroidal anti-inflammatory medications (NSAIDs) such as aspirin and ibuprofen should be avoided as they can increase bleeding.
Prevention involves avoiding being bitten by mosquitoes while in regions where dengue fever occurs.
The following measures can protect against acquiring dengue fever:
- Wear clothing/hats that cover the arms, legs, and head
- Wear shoes rather than sandals or jandals
- Apply insect repellent to exposed skin. The most effective repellents contain DEET (diethyl toluamide) at a concentration of 30–50%
- Apply permethrin insecticide to clothes and shoes
- Sleep under mosquito nets treated with permethrin
- Use electric insect-repellent devices or mosquito coils
- Try to stay in accommodation that has insect screens on doors and windows or is air-conditioned.
Further information and support
The New Zealand Ministry of Foreign Affairs and Trade operates an official website – www.safetravel.govt.nz – that provides advice and travel alerts for New Zealanders living or travelling abroad. The website's health alerts include advice of outbreaks of diseases such as dengue fever.
Mayo Clinic (2018). Dengue fever (Web Page). Rochester, MN: Mayo Foundation for Medical Education and Research. https://www.mayoclinic.org/diseases-conditions/dengue-fever/symptoms-causes/syc-20353078 [Accessed: 15/01/20]O’Toole, M.T. (Ed.) (2017). Dengue fever. Mosby’s Dictionary of Medicine, Nursing & Health Professions (10th ed.). St Louis, MI: Elsevier.
DermNet New Zealand (2017). Dengue fever (Web Page). Hamilton: DermNet New Zealand Trust. https://www.dermnetnz.org/topics/dengue/ [Accessed: 15/01/20]
Health Intelligence Team (2017). Notifiable diseases in New Zealand: Annual Report 2017 (PDF). Porirua: Institute of Environmental Science and Research Ltd. https://surv.esr.cri.nz/PDF_surveillance/AnnualRpt/AnnualSurv/2017/2017AnnualNDReport_FINAL.pdf Ministry of Health (2018). Dengue (Web Page). Wellington: New Zealand Government Ministry of Health. http://www.health.govt.nz/your-health/conditions-and-treatments/diseases-and-illnesses/sore-throat [Accessed: 15/01/20]
World Health Organisation (2020). Dengue and severe dengue. https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue [Accessed: 30/03/20].
Last Reviewed – March 2020