Malaria risk by country

How to read the table

Each row is a country where CDC advises malaria medicine. The areas column is CDC's wording, shortened where it runs long; the full text, with altitudes and province names, is on the country's CDC page and on this site's country pages. The drugs column lists those CDC names for the country. A country can appear even if the risk is limited to a small region; the decision for a given itinerary depends on where you stay, when, and how.

Resistance, the line that picks the drug

Chloroquine was once the standard malaria drug; Plasmodium falciparum now resists it across Africa, Asia and South America. Where CDC writes "Chloroquine" in the resistance line, chloroquine is not used for prevention. Where it writes "None", in Mexico, Central America, Haiti, the Dominican Republic and the Koreas, chloroquine still works and is listed with the others, sometimes with primaquine where Plasmodium vivax dominates. In the Mekong countries, Burma, Cambodia, Laos, Thailand and Vietnam, resistance to mefloquine as well narrows the list in the border areas where malaria persists. These lines matter more than the country name: two countries on the same continent can need different drugs.

Where the risk is limited

Many travelers on the list never enter a risk area. In Thailand, CDC places malaria primarily in the provinces bordering Burma, Cambodia and Malaysia, reports rare to few cases in Bangkok, Chiang Mai, Phuket and Koh Samui, and none on the islands of Krabi Province or in Pattaya City. In Mexico, CDC names Campeche, Chiapas and the southern part of Chihuahua, with rare cases in four other states, and none along the border with the United States. In Peru, risk covers all areas below 2,500 meters east of the Andes, Iquitos and Puerto Maldonado included, while Lima Province, the city of Cusco, Machu Picchu and Lake Titicaca have none. In India, by contrast, CDC lists all areas below 2,000 meters, cities included, and much of sub-Saharan Africa has risk throughout, including the cities and game parks. A prescriber looks at the exact itinerary, the season and the lodging before writing a prescription, and may advise bite prevention alone for low risk areas.

Season, lodging and length of stay

Several CDC pages add a season to the area: Afghanistan lists April to December, and other countries name the rainy months. Outside them, risk drops but rarely to zero, which is why prescribers often follow the area rule all year. Lodging counts as well. A night in a screened, air-conditioned hotel in a risk district exposes a traveler far less than camping or a village homestay in the same place, and long stays add up the nights. Travelers visiting friends and relatives in their country of origin are among the groups most often diagnosed with malaria after a trip in the United States, in part because they stay longer, in homes rather than hotels, and sometimes skip tablets in the belief that they are immune. Immunity acquired in childhood fades within a few years of living elsewhere.

Species

CDC also names the species. Plasmodium falciparum causes most severe malaria and most deaths and dominates in Africa. Plasmodium vivax, common in Asia and the Americas, can hide in the liver and relapse months later, which is why primaquine or tafenoquine is sometimes added after the trip for people heavily exposed. The species line on each CDC page tells a prescriber which of these concerns applies.

Countries off the list

For the other 158 destinations, CDC's pages give no prescription advice: there is no malaria transmission, or the risk is so low that bite prevention is enough. Some of them mention rare cases or a recent history of transmission; the country page says so when it does. A traveler going on from one of them to a country in the table needs the tablets for that part only, starting before the border.

The malaria pills page counts tablets for any stay, and each country page of this site shows CDC's full malaria text.