Travelling Outside of Hong Kong: How to Prevent Malaria

As cross-border travel in Hong Kong is slowly starting to resume¹, it remains important to get medical advice before departing to learn about the likelihood of disease in the countries you plan to visit. One travel-related disease is malaria, which is found in destinations such as Sub-Saharan Africa. The disease spreads by bites from infected mosquitoes. Fortunately, there are methods to both prevent and treat malaria².

Travel Destinations with a High Risk for Malaria

Only a few countries are considered malaria-free, and the World Health Organization has recently declared China as one of them³. In Hong Kong, malaria has been well controlled over the past decades and it is very rare to contract malaria from mosquito bites. Between the years 1996 to 2005, 521 cases were reported, of which 98.7% were imported⁴.

The risk of malaria infection in Hong Kong remains low. However, it’s important to take note of necessary prevention methods if you are travelling to the following tropical and subtropical areas of the world⁵:

• Asia (Thailand, Malaysia, Vietnam, etc)
• Central and South America (Colombia, Brazil, Peru, etc)
• Some Pacific Islands (Papua New Guinea and the Solomon Islands)
• Haiti and the Dominican Republic
• Parts of the Middle East (Yemen and Saudi Arabia)
• Sub-Saharan Africa (Nigeria, The Democratic Republic of Congo, Mozambique, etc)

Source: Travel Health Service⁵

For a detailed breakdown of all regions, visit the Centers for Disease Control and Prevention’s malaria information by country, table here.

What is Malaria?

Malaria is a serious disease that is spread by infected female Anopheline mosquitoes. People who have malaria exhibit high fevers, shivering chills and flu-like symptoms⁶. A full recovery is possible when malaria is diagnosed and treated quickly. As soon as a blood test shows the presence of a malaria parasite, treatment should begin⁶.

Malaria Symptoms

Symptoms of Malaria can develop as quickly as 7 days after an infected bite. Initial symptoms include⁷:

• A high temperature of 38℃ or above
• Feeling hot and shivery
• Headaches
• Vomiting
• Muscle pains
• Diarrhoea

Malaria is tested by a diagnostic test, where a drop of blood is examined under a microscope for the presence of malaria parasites⁷.

Malaria Treatments

Antimalarial medications that prevent malaria can also treat it. However, if you took an antimalarial to prevent malaria, you shouldn’t receive the same one to treat it. So make sure to inform your doctor about the antimalarials you've taken⁸.

The type of antimalarial medicine you'll need and how long you will need to take it will be determined by the following factors⁸:

• The type of malaria you have
• Where you caught malaria
• The severity of your symptoms
• Whether you took preventative antimalarial tablets
• Your age
• Whether you're pregnant

Our General Practice clinic offers the following antimalarial drugs on-site:

• Hydrochloroquine Sulfate

Hydroxychloroquine, a derivative of Chloroquine, along with Atovaquone/Proguanil, is often the first drug to be used, depending on the strain of malaria. It is also the best tested, least expensive and most available medication for malaria.

• Atovaquone/Proguanil (Malarone)

The recommended treatment if the strain has Chloroquine resistance and is not severe. It comes in a tablet form under the name Malarone and is taken orally. An intravenous treatment of Atovaquone/Proguanil might also be used as an interim treatment in more severe cases of malaria.

• Doxycycline

An antibiotic drug that can be used as a preventive measure prior to travelling. It might be used to complement another drug or used as a post-malaria recovery drug intravenously.

The course of medication depends on the type of malaria you have. Please speak to your general practitioner for more information.

Is there a Vaccine for Malaria?

Although there is progress in developing malaria vaccines over the last ten years, there is presently no licensed malaria vaccine on the market⁵.

Preventing Malaria

Avoiding mosquito bites is the first and best line of defence against contracting malaria. Travellers can also protect themselves by taking antimalarial medication⁹.

Avoid Mosquito Bites

• Stay somewhere with good air conditioning and doors and windows with screens. If this isn't possible, ensure that all doors and windows are properly closed.
• If you don't have access to air conditioning, sleep under a mosquito net that has been treated with insecticide.
• Apply insect repellent to your skin and in your sleeping areas. Diethyltoluamide (DEET) is the most effective repellent and is available in sprays, roll-ons, sticks, and lotions. Remember to reapply it regularly.
• Instead of shorts, opt for light, loose-fitting trousers and long-sleeved shirts. Especially during the evening, as this is when mosquitoes are most active.

Antimalarial Medication

If you are travelling to a region with a risk of malaria, speak to your general practitioner about which medications you should take. You might need to take certain medicines during your travels and several days before and after you travel⁸.

Antimalarials reduce your risk of infection by 90%⁸. However, it remains essential that you take the necessary precautions to avoid mosquito bites.

Conclusion

Although there is no vaccine for malaria, it can be prevented by avoiding mosquito bites and treating it with anti-malarial medication. Speak to your general practitioner if you plan to visit a country with reported malaria transmission and always ensure you're complying with international vaccine regulations. 

References

1. South China Morning Post. (2021). ‘Coronavirus: resuming cross-border travel high on Hong Kong agenda as city eases quarantine rules for fully jabbed residents, travellers.’ The Coronavirus Pandemic. 21 June 2021. Available at: <https://www.scmp.com/news/hong-kong/health-environment/article/3138131/coronavirus-hong-kong-reduce-covid-19-quarantine> [Accessed 09 July 2021].
2. Centre for Health Protection. (2019). ‘Malaria’. Department of Health. 15 October 2019. Available at: <https://www.chp.gov.hk/en/healthtopics/content/24/30.html> [Accessed 29 June 2021].
3. The World Health Organization. (2021). ‘From 30 million cases to zero: China is certified malaria-free by WHO.’ WHO. 30 June 2021. Available at: <https://www.who.int/news/item/30-06-2021-from-30-million-cases-to-zero-china-is-certified-malaria-free-by-who> [Accessed 09 July 2021].
4. Centre for Health Protection. (2006). ‘Epidemiology of Malaria in Hong Kong.’ Department of Health. March 2006. Available at: <https://www.chp.gov.hk/files/pdf/epidemiology_of_malaria_in_hong_kong_r.pdf> [Accessed 29 June 2021].
5. Travel Health Service. (2020). ‘Travel Related Diseases.’ Department of Health. 28 December 2020. Available at: <https://www.travelhealth.gov.hk/english/travel_related_diseases/malaria.html> [Accessed 29 June 2021].
6. Centers for Disease Control and Prevention. (2021). ‘The Disease.’ CDC. 26 January 2021. Available at: <https://www.cdc.gov/malaria/about/faqs.html> [Accessed 29 June 2021].
7. National Health Service. (2018). ‘Malaria.’ NHS. 22 August 2018. Available at: <https://www.nhs.uk/conditions/malaria/> [Accessed 29 June 2021].
8. National Health Service. (2018). ‘Antimalarials.’ NHS. 22 August 2018. Available at: <https://www.nhs.uk/conditions/malaria/treatment/> [Accessed 29 June 2021].
9. National Health Service. (2018). ‘Malaria Prevention.’ NHS. 22 August 2018. Available at: <https://www.nhs.uk/conditions/malaria/prevention/> [Accessed 29 June 2021].