Every year, about 1,300 people in the United States learn they have malaria. Most are travelers, and many are blasM-i about malaria.
If they had taken antimalarial pills as directed - before, during and after the trip - and followed simple precautions, they would have greatly reduced the risk of getting the mosquito-transmitted disease.
Worldwide, malaria affects up to 500 million people a year; 1 million die of the disease annually. It is endemic in more than 100 countries and territories, according to the federal Centers for Disease Control and Prevention in Atlanta.
Although efforts are continuing, experts say development of a commercial vaccine is not imminent - nor will it be ideal when it arrives. The life cycle of the malaria parasite is complicated, and the antigens (the proteins found on the organism that trigger the body's response) are constantly changing, making development of a vaccine difficult.
Dr. Bradley Connor, a New York physician specializing in travel medicine, and other doctors advise people to take antimalarial pills if they are visiting areas prone to the disease.
But fewer than a third of travelers take the antimalarial drugs as prescribed, according to a study of 81 people published in the January issue of the Journal of Travel Medicine.
"You travel to get your mind off daily life," says Dr. Vincent Lo Re, an infectious disease physician at the University of Pennsylvania School of Medicine in Philadelphia.
He also notes the importance of preventive measures such as using bed netting and insect repellent, preferably with 30 percent DEET. Wearing long sleeves and pants is also recommended.
Symptoms of malaria include headache, fatigue, chills, fever, plus nausea and vomiting. Typically, symptoms surface 10 days to a month after infection, but they can occur earlier than that or later - even a year or longer, according to the CDC.
Kathleen Doheny is a freelance writer for the Los Angeles Times.