CDC Warns of Imported Malaria – U.S. Cases Reach 40 Year High

Increase underscores importance of taking recommended medicines to prevent malaria when traveling

In 2011, 1,925 malaria cases were reported in the United States, according to data published in a supplement of the Morbidity and Mortality Weekly Report (MMWR) released today by the Centers for Disease Control and Prevention (CDC). This number is the highest since 1971, more than 40 years ago, and represents a 14% increase since 2010. Five people in the U.S. died from malaria or associated complications.

Almost all of the malaria cases reported in the U.S. were acquired overseas. More than two-thirds (69%) of the cases were imported from Africa, and nearly two-thirds (63%) of those were acquired in West Africa. For the first time, India was the country from which the most cases were imported. Cases showed seasonal peaks in January and August.

“Malaria isn’t something many doctors see frequently in the United States thanks to successful malaria elimination efforts in the 1940s,” said CDC Director Tom Frieden, M.D, M.P.H. “The increase in malaria cases reminds us that Americans remain vulnerable and must be vigilant against diseases like malaria because our world is so interconnected by travel.”

Malaria is caused by a parasite transmitted by the bite of an infective female Anopheles mosquito. In 2010, it caused an estimated 660,000 deaths and 219 million cases globally. The signs and symptoms of malaria illness are varied, but the majority of patients have fever. Other common symptoms include headache, back pain, chills, increased sweating, muscle pain, nausea, vomiting, diarrhea, and cough. Untreated infections can rapidly progress to coma, kidney failure, respiratory distress, and death.

“Malaria is preventable. In most cases, these illnesses and deaths could have been avoided by taking recommended precautions,” said Laurence Slutsker, M.D., M.P.H., director of CDC’s Division of Parasitic Diseases and Malaria. “We have made great strides in preventing and controlling malaria around the world. However, malaria persists in many areas and the use of appropriate prevention measures by travelers is still very important.”

Travelers to areas with malaria transmission can prevent the disease by taking steps such as use of antimalarial drugs, insect repellent, insecticide-treated bed nets, and protective clothing.

Travelers in the United States should consult a health-care provider prior to international travel to receive needed information, medications, and vaccines. CDC provides advice on malaria prevention recommendations on-line. If a traveler has symptoms of malaria, such as fever, headaches, and other flu-like symptoms, while abroad or on returning home, he or she should immediately seek diagnosis and treatment from a health-care provider.

Clinicians should consult the CDC Guidelines for Treatment of Malaria and contact CDC’s Malaria Hotline for case management advice, as needed. Malaria treatment recommendations can be obtained online or by calling the Malaria Hotline (770-488-7788 or toll-free at 855-856-4713).

Source: Centers for Disease Control (CDC)

Areas Where Malaria Occurs

QUESTION

Can you please tell me the high, low and no risk areas for malaria.

ANSWER

Malaria requires certain climatic conditions, both for its own development as well as for the survival of its vector mosquitoes. As such, malaria transmission is concentrated in lowland areas of the tropics, where there is sufficient freshwater for mosquito breeding. However, malaria can also seasonably be transmitted in areas away from the tropics. Similarly, some tropical and sub-tropical areas have implemented successful control programs which has significantly reduced or even eliminated transmission.

Currently, high risk areas for malaria transmission include most of sub-Saharan Africa (except for the highlands of Ethiopia, Tanzania, Kenya and Eritrea – areas over 1800 meters of altitude tend to have less malaria), most of northern South America (except areas over 2000m, and many urban cities are also free of malaria), parts of Central America, some Caribbean islands, India, south-east Asia (again, apart from highland areas) and Oceania. Low risk areas include parts of southern Africa (i.e. northern South Africa), parts of Central America (including most of Mexico, though some parts of the south may be considered higher risk), parts of the Middle East and parts of China. There is no known malaria in North America, Europe, most of North Africa, Australia, New Zealand, Japan, the eastern coastal regions of Brazil, most of southern South America and northern Asia. For a detailed and up to date map of malaria risk around the world, please see the Malaria Map

Malaria in the United States, Years Later

QUESTION

For years, I have questioned what sickness I got years ago after a series of bug bites in a bayou in New Orleans. I’ve just read the symptoms described here and they fit everything I was suffering with. I even had problems with my liver, but I was never tested for Malaria because I had immediately left New Orleans for Italy. I never thought of mentioning it. This mysterious illness cropped up in different forms over the years and really I was never the same after it. It has been almost 12 years, and I still suffer from recurring illness which antibiotics help for a while, but it always comes back. Could it be that I have had Malaria in my system all this time?

ANSWER

While malaria was officially eradicated from the US in the 1950s, certainly the swamps and bayous of Louisiana and the rest of the Gulf were a key habitat and a major source of transmission prior to eradication. I just found a news report in the New York Times from October 1883 which reported 16 deaths due to “malarial fever” in the previous week alone!

While these days, virtually all of the 1,500 or so cases of malaria observed in the US every year are attributed to overseas travel, in 2002 a handful of cases of malaria in northern Virginia were believed to be due to local transmission. Prompt treatment, personal protective measures (such as screening houses) and vector control quickly quelled that mini-outbreak.

Given this history along with your symptoms, and particularly your recurrent episodes of fever, I would not rule out malaria, obtained in Louisiana, as a possibility! You should talk to your doctor about the possibility of a serological test for the antibodies against malaria—if positive, you should try to have a blood test done next time you have the recurrence of symptoms. If malaria is confirmed, you should report your case to the Centers for Disease Control (CDC) Domestic Malaria Unit, which monitors all malaria cases in the US.