Travel Guard® Malaria Health Advisory: What Travelers Should Know

Malaria, or “Paludismo,” is a mosquito-borne disease caused by a parasite. People with malaria often experience fever, chills and flu-like illness. Left untreated, they may develop severe complications and die. In 2020, an estimated 241 million cases of malaria occurred worldwide and 627,000 people died, mostly children, in sub-Saharan Africa.
Those at highest risk for severe disease include children under the age of five and pregnant women, who are at risk for anemia and delivering low birthweight newborns.

General information

There are approximately 3,500 species of mosquitoes grouped into 41 genera. Human malaria is transmitted only by females of the genus Anopheles. Of the approximately 430 Anopheles species, only 30-40 transmit malaria (i.e., are “vectors”) in nature. The rest either bite humans infrequently or cannot sustain development of malaria parasites.

Geographic distribution

Anophelines are found worldwide except in Antarctica. Malaria is transmitted by different Anopheles species in different geographic regions. Within geographic regions, different environments support a different species.

Anophelines can transmit malaria are found not only in malaria-endemic areas, but also in areas where malaria has been eliminated. These areas are thus at risk of re-introduction of the disease.

Over 95% of the world’s malaria burden occurs in Africa.  Twenty-nine countries account for the majority in that continent - including Nigeria, DRC, Uganda, Mozambique, Angola and Burkina Faso. 

Malaria hotspots

https://www.cdc.gov/malaria/malaria_worldwide/impact.html

Mode of transmission

Usually, people get malaria by being bitten by an infected female Anopheles mosquito. Only Anopheles mosquitoes can transmit malaria and they must have been infected through a previous blood meal taken from an infected person. Following the bite of the mosquito, individuals are generally symptomatic in one to three weeks.

Risk assessment for travelers

It is important to consider factors such as types of accommodations and activities as well as the reason and duration of travel as a part of any risk assessment. For example, short-term business travelers staying in air-conditioned hotels may be at lower risk than backpackers or adventure travelers.

Because malaria-transmitting mosquitoes are most active at night, include an assessment of the likelihood that the travelers might be spending time outdoors in the evenings for dining or entertainment. Longer durations of stay in a malaria-endemic area may also increase the chance that an individual might become infected.

Mosquito avoidance measures

Contact with mosquitoes can be reduced by remaining in well-screened areas, sleeping under mosquito nets (preferably insecticide-treated nets), using an effective insecticide spray in living and sleeping areas during evening and night-time hours, and wearing clothes that cover most of the body.

All travelers should use an effective mosquito repellent, such as those that contain DEET. Repellents should be applied to exposed parts of the skin when mosquitoes are likely to be present. If travelers are also wearing sunscreen, sunscreen should be applied first and insect repellent second. In addition to using a topical insect repellent, a permethrin-containing product may be applied to bed nets and clothing for additional protection against mosquitoes.

Preventive measures by medication

No antimalarial drug is 100% protective and must be combined with the use of personal protective measures, (i.e., insect repellent, long sleeves, long pants, sleeping in a mosquito-free setting or using an insecticide-treated bed net).

Recommendations for drugs to prevent malaria differ by country of travel and can be found in Malaria Information by Country. Suggested drugs for each country are listed in alphabetical order and have comparable efficacy in that country.
https://www.cdc.gov/malaria/travelers/country_table/a.html

All of the commonly used medications for malaria prophylaxis may have side effects and may interact with other medications.  It is highly recommended that travelers consult with a travel medicine specialist prior to travel to any location where malaria is endemic. 

The most frequently used antimalarials are:

Atovaquone/Proguanil (Malarone), Adults: one adult tablet daily.

• Good choice for shorter trips because you only have to take the medicine for seven days after traveling rather than four weeks.
• Very well tolerated medicine – side effects uncommon.
• Cannot be used by women who are pregnant or breastfeeding a child who weighs less than 5 kilograms (11 pounds).
• Cannot be taken by people with severe renal impairment.

Chloroquine, Adults: 300 mg base (500 mg salt), once/week.

• Some people would rather take medicine weekly.
• Good choice for long trips because it is taken only weekly.
• Cannot be used in areas with chloroquine or mefloquine resistance.
  

Doxycycline, Adults: 100 mg daily.

• Some people prefer to take a daily medicine.
• Good for last-minute travelers because the drug is started one to two days before traveling to an area where malaria transmission occurs.
• Tends to be the least expensive antimalarial.
• Cannot be used by pregnant women and children under eight years old.

Bibliography:

• https://www.cdc.gov/malaria/about/