Malaria was eliminated from the United States in the early 1950s. Yet, the Centers for Disease Control (CDC) receive over a thousand reports of the illness annually, and in 2011 set a 40 year record high. The state of Maryland sees one hundred or more of those cases every year. On Nov. 12, David Blythe, MD, MPH, an epidemiologist with the Maryland Department of Health and Mental Hygiene, spoke with the Examiner about some of the reasons why.
Virtually all of Maryland's malaria patients, Dr. Blythe told me, caught their illnesses overseas. When a case of malaria is diagnosed, the treating physician reports it to one of 24 local health jurisdictions in the state. Those local agencies perform a case investigation and forward the information on to the state.
Analysis of published data finds that the majority of malaria cases in Maryland from 2005 through 2012 were from two counties in the Maryland National Capital Region. Prince George's County reported 296 cases in those seven years, and Montgomery County reported 189. The entire state, for the same period, reported 753 malaria cases.
Blythe echoed the findings of the CDC for 2011. Most of Maryland's malaria cases were acquired in Africa, by patients visiting family and friends. Many of the patients are immigrants. He said that as many as 80 percent of those individuals did not take preventive medications. He could not speculate on the reasons for that behavior.
He stressed that travelers should follow the recommendations of the CDC for the nations that they plan to visit and obtain the correct medications to prevent catching malaria. These prophylactic medications are not the same for every country and the dose to take may vary by patient. The medications, Blythe said, should be readily available with a physician's prescription.
Dr. Blythe talked about the potential for a return to locally acquired malaria, since the mosquito species that carries the illness is native to Maryland. Another mosquito borne illness, West Nile, has established itself because it has a reservoir of infections in birds. He speculated that the lack of such a reservoir for malaria would make it much more difficult for the disease to reestablish itself in the state, since only humans and mosquitoes can become infected by the malaria parasite.
Through Nov. 2, 2013, the CDC has found 1,069 malaria cases in the United States this year. Maryland has reported 123 cases to the CDC. New York leads the nation, with 210 cases reported.