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Updated 23 April 2021

Malaria remains one of the world’s leading killers and seafarers must not lower their guard when visiting an area where there is a risk of exposure to this mosquito-borne disease. Remember also that malaria could easily be misdiagnosed as COVID-19.

According to the WHO’s latest World malaria report, the last two decades can be described as “a period of unprecedented success in malaria control that saw 1.5 billion cases and 7.6 million deaths averted.” Despite this remarkable progress, the global gains in combatting malaria have levelled off in recent years. The estimated number of malaria deaths in 2019, at 409 000, remained virtually unchanged over the previous year. The WHO also reports that antimalarial drug resistance has emerged as a threat to global malaria control efforts and that, in 2020, the COVID-19 pandemic became a serious additional challenge to malaria response worldwide. When the world’s attention was switched to COVID-19, many countries experienced disruptions in access to lifesaving health care and in the delivery of key malaria commodities.

Early symptoms of malaria and COVID-19, such as fever, headache, and fatigue, are very similar and with the global presence of COVID-19, malaria can easily be misdiagnosed as COVID-19. Therefore, now more than ever, it is important that ship operators focus on the risk of malaria transmission. It must be ensured that seafarers are familiar with the signs and symptoms of malaria, understand that malaria is serious and potentially fatal, and implement prevention measures when their vessel is destined for areas where there is a potential risk of malaria.

Key facts about malaria

  • Malaria is a life-threatening disease caused by parasites transmitted to people through the bites of infected female Anopheles mosquitoes.
  • The Anopheles mosquito is active mainly at night, between dusk and dawn.
  • Malaria is an acute febrile illness and symptoms usually appear 10–15 days after the infective mosquito bite. The first symptoms - fever, headache, and chills - may be mild and difficult to recognise as malaria. If not treated within 24 hours, the disease can progress to severe illness, often leading to death. Immediate medical attention should therefore be sought to ensure early diagnosis.
  • In 2019, there were an estimated 229 million cases of malaria in 87 countries. The estimated number of malaria deaths stood at 409 000.
  • Most malaria cases and deaths, more than 90%, occur in the WHO African Region. However, the WHO regions of South-East Asia, Eastern Mediterranean, Western Pacific, and the Americas are also at risk.
  • In 2019, six countries accounted for more than 50% of all malaria deaths worldwide: Nigeria (23%), the Democratic Republic of the Congo (11%), the United Republic of Tanzania (5%), Mozambique (4%), Niger (4%) and Burkina Faso (4%).
  • And most importantly, malaria is preventable and curable.

(source: WHO)

Recommended precautions

Shipowners and operators with vessels trading to countries and areas with ongoing malaria transmission should ensure that these vessels are able to deal with the various challenges that this disease can bring. Depending on the area of trade, risks related to other mosquito-borne diseases, such as dengue, yellow fever, chikungunya and zika, should also be taken into account when planning for the next voyages. The following precautions should be considered:

Prior to visiting affected areas

  • Monitor the WHO website and similar sources for official advice regarding any ongoing outbreaks. Contact a medical practitioner if in doubt.
  • Review all the ports to be visited and evaluate the risk. Consider the length of stay in an affected area, time spent at sea, in port, on rivers, etc., as well as planned shore leaves by the crew.
  • Inform the crew about the risks and the precautions to be taken as well as actions to be taken if illness occurs at sea. Stress that a headache, fever and flu-like symptoms are always grounds for contacting the medical officer.
  • Ensure sufficient supplies of effective insect repellents, light coloured boiler suits, porthole/door mesh screens and bed-nets.
  • Consider, in close co-operation with a medical doctor and based on the vessel’s expected exposure time in an affected area, if the crew should take an antimalarial drug and the type of medication to be use. Considerations should include efficacy, local resistance patterns, simplicity of dosage schedule, and possible adverse effects of the medication.

During a visit to affected areas

  • Implement measures to avoid mosquito bites, e.g. wear protective clothing, stay in air-conditioned screened accommodation areas, use undamaged insecticide-treated bed-nets in sleeping areas. Use effective insect repellents on exposed skin and/or clothing as directed on the product label and when using a sunscreen, the recommendation is to apply sunscreen first, followed by repellent.
  • If crew members are taking anti-malarial drugs, implement a method of control to ensure they take the medication at the prescribed times, e.g. via a log book.
  • Remove pools of stagnant water, dew or rain in order for the vessel not to create its own mosquito breeding grounds. Pay particular attention to areas such as lifeboats, coiled mooring ropes, bilges, scuppers, awnings and gutters.

After a visit to affected areas

  • Seek medical advice over the radio if malaria is suspected on board. Normally the vessel is in port only for a short time and will most probably be back at sea when symptoms are noticed due to an incubation period of several days.
  • Place the patient under close observation and undertake the required onboard treatment, preferably in close co-operation with a medical doctor. Evacuation may be the only solution if the patient’s condition does not improve.

Sources of information

Prevention requires vigilance so stay up to date! Here are some recommended sources of information:

  • Detailed information about malaria and other mosquito-borne diseases – their characteristics, treatment, prevention, geographical distribution and recent outbreaks – are available via WHO’s “Health topics”.
  • The United States Centers for Disease Control and Prevention (CDC) provides similar information via its “Disease & Conditions A-Z Index”.
  • The CDC’s general “Destination List” is a good starting point for a voyage specific risk assessment related to mosquito-borne diseases.

National governments may also publish safety alerts concerning seasonal outbreaks of the diseases on their “safe travel” websites. Relevant information can also be obtained from medical doctors and local vaccination offices.