In mid-August, the Maryland Department of Health issued a notice stating that the agency had confirmed a rare positive case of locally acquired malaria and urged Marylanders to take precautions to avoid future mosquito bites. But locally acquired malaria is rare in the United States, and this unique case prompted a new paper published by federal health officials, highlighting the efforts that led to the final diagnosis.
State and federal public health officials say the malaria case identified in Maryland can help inform the challenges of diagnosing locally acquired cases and highlight collaboration among health agencies. State and public health professionals to help inform the public of malaria risks.
“The identification of a locally acquired case was quite unusual and triggered a public health response that involved local health departments, state health departments – that’s where I am – as well as “a collaboration with the CDC,” said Monique Duwell of the Maryland Department of Health. Center for Infectious Disease Surveillance and Outbreak Response.
This is particularly important because other states are also detecting locally acquired cases of malaria. Earlier this year, such cases were identified in Texas and Florida, the CDC reports. While all infected people received treatment and were recovering, according to the CDC, malaria can be dangerous, even fatal, if left untreated.
“So with these types of unusual cases, whether it’s locally acquired malaria or some other unusual event, it’s quite common for public health officials to want to share these findings with their colleagues,” said Duwell.
A recent article titled “Notes from the Field: Locally Acquired Mosquito-Transmitted Plasmodium falciparum Malaria — National Capital Region, Maryland, August 2023,” describes the detection and response to a single malaria case identified in Maryland in early August .
Duwell was the lead author of the report, which was featured in last week’s edition of the CDC’s Morbidity and Mortality Weekly Report (MMWR). The MMWR is a comprehensive collection of public health studies and information for physicians, public health practitioners, researchers, epidemiologists, educators, and other medical-related professions.
Typically, about 2,000 cases of malaria are detected each year in the United States, with about 200 reported outside Maryland, according to the CDC. And locally acquired cases are even rarer. Until the August case, Maryland had not seen a case of locally acquired malaria in 40 years.
Duwell explained that almost all malaria cases identified in the United States come from people who have recently traveled to areas where malaria is endemic, such as parts of Africa, Asia and other countries.
According to the CDC report, “imported cases” from outside the United States may “represent a potential source of infection” leading to infections in people who have not traveled outside the country.
Duwell explained: “A person travels to a country where malaria is known…and they contract malaria or become infected with malaria. If they return to the United States and are bitten by the type of mosquito that transmits malaria, and that same mosquito then bites someone else… who has not traveled to that country, then they can infect that person.
Duwell’s report describes some of the challenges of identifying malaria, especially if an infected person has not traveled recently. This was the situation in the Maryland case.
On Aug. 6, a previously healthy Marylander with no recent history of international travel was evaluated for a 7-day history of fever, malaise and body aches, according to the report.
But reaching a possible diagnosis of malaria was a real challenge.
Malaria is a disease caused by a parasite that can be transmitted by certain mosquito bites, but its symptoms can look very similar to a separate disease also caused by a parasite called babesiosis. which is transmitted by tick bites.
To make the initial diagnosis more difficult, the person at the center of the case indicated that they took regular walks and had reported a recent tick attachment. The individual was even asked to undergo a 7-day treatment for babesiosis while laboratory tests were performed and evaluated.
“We see cases of locally acquired babesiosis here in Maryland, between 5 and 13 cases each year,” Duwell said. “It’s not a huge number, but we’re seeing it – certainly more common than locally acquired malaria. So it’s just another piece of the diagnostic puzzle.
Laboratory results from the blood samples ultimately confirmed the diagnosis of malaria.
The case prompted Maryland health officials to alert residents and issue a public reminder about preventing mosquito bites on August 18. Preventative measures include wearing loose, long-sleeved clothing, preventing mosquitoes from entering the home, and draining nearby stagnant water to keep mosquitoes out. to lay eggs.
The Maryland Department of Agriculture also helped by conducting surveillance for malaria-carrying mosquitoes.
The report concludes that the Maryland malaria case “highlights common challenges in diagnosing malaria, including differentiation from babesiosis…and highlights the need for coordinated efforts among public health officials, clinicians, laboratories and the public to prevent, detect and respond to such cases. .”
Duwell also had some advice for Marylanders.
“One way to prevent such cases is for travelers to take malaria prophylactic medications before traveling to other parts of the world where malaria is endemic,” she said.
She added that as winter approaches, the risk of being bitten by a mosquito would be reduced in Maryland, but holiday travel could add additional risks.
“We know that holiday travel is coming and people are often traveling to these countries where malaria is endemic. We just want to encourage anyone traveling to these areas to contact their doctor before leaving to obtain the appropriate medication to prevent malaria. protect them, their family members and others,” she said.
