The U.S. has recorded its first cases of malaria in the home country in a long time, but there’s no reason to be concerned.
In the past for only the second time in the past 20 years for the first time in 20 years, this year, the U.S. has recorded homegrown malaria cases.
The country experiences between 2,000 and 2,500 malaria cases every year, due to travel to malaria-endemic regions like sub-Saharan African countries and regions of South America and Southeast Asia–but the nine cases that have been locally transmitted observed so far in the year were contracted by individuals who had not recently visited these regions. Seven cases were reported in Florida, as well as one each within Texas and Maryland.
Malaria experts believe this tiny number of cases aren’t a reason for concern. The possibility of contracting malaria outside of the U.S. is extremely unlikely. However, they stress that if malaria or other illnesses are returning or appearing in areas that they’ve never before the case, this should be a cause for concern.
Malaria’s History in North America
In the 20th century’s early years “malaria was common even as far north as Cleveland,” states Prakash Srinivasan, PhD MS. an assistant professor at the Department of Molecular Microbiology as well as Immunology in the Johns Hopkins Malaria Research Institute.
The disease was prevalent in the U.S. until the 1950s. In 1951, malaria was considered as eliminated from the nation.
Numerous factors played a role in achieving this position. Industrialization, clearing areas of wetlands where mosquitoes breed and pesticides as well as windows screens, on top of public health measures such as malaria-prevention medicines and improved diagnostics — were “game changers” in the U.S. and most other Western countries when it came to eliminating malaria as Srinivasan explains.
Anopheles mosquitoes, the genus responsible for malaria is still throughout the U.S. “But because malaria transmission in the United States has not been a big issue, there is no surveillance of Anopheles populations,” explained Photini Sinnis MD who is a Professor at MMI and the Johns Hopkins Malaria Research Institute.
The Vectors and the Parasites
The transmission of malaria “is a relationship between a mosquito, a parasite, and a person,” declares Sinnis. Female anopheles mosquito needs to be infected by the malaria parasite to spread the infection. However, there are many factors to consider.
The life span of an Anopheles mosquito is usually one or two weeks to one month. In this period, female mosquitoes eat in blood. Blood is the only thing is needed to provide energy for their mature eggs. A mosquito typically consumes two blood meals throughout its life. The malaria parasite can remain on the body of the mosquito over a period of weeks, which means it is possible to be transmitted to multiple people. However, “the chances are pretty low,” Srinivasan explains.
That’s the reason we’re seeing isolated cases rather than groups or large-scale outbreaks.
Another issue Another factor is that not every Anopheles species transmit malaria in the identically.
“It’s related to how anthrophilic mosquitoes are and how it is attracted to bite human beings. Malaria parasites are extremely specific to species,” Sinnis explains. The different kinds of Anopheles in the U.S. will bite humans “maybe 30% to 50% of the time.” If a person is not in the vicinity, they could be bitten by a dog, or a different mammal, breaking this cycle infections.
It is believed that Anopheles mosquitoes that live in sub-Saharan Africa, however are able to bite humans 98% of the time, making it simpler to allow the vicious cycle of human infection to go on.
Another reason why there are many different malaria-related illnesses that are the same is that there many malaria-causing parasites. The most lethal parasite is Plasmodium falciparum. According to Sinnis it is most prevalent in sub-Saharan Africa, in which malaria kills more than 600,000 people annually – 95 percent of whom are children younger than 5 years old.
“It is estimated that one child dies of malaria every minute,” declares Srinivasan.
A different malaria-causing parasite called Plasmodium viax is more common throughout South America and Southeast Asia and is generally associated with less severe illness, and is consequently less harmful.
How Malaria Likely (re)Appeared in the U.S.
Anopheles mosquitoes with the capacity to carry malaria are still present throughout the U.S.–they’ve been given very few occasions to transmit the parasite because there aren’t many affected people to take in.
Experts believe that this latest outbreak of locally transmitted cases is likely to have occurred due to a specific sequence of events aligned the following: A person suffering from malaria was traveling across the U.S. from a malaria-endemic region and was bit by the nearby Anopheles mosquito. It carried the parasite to the next location and then bit another and transmitted the parasite.
Although the situation in Maryland is proven to be connected to P. falciparum, the cases located in Florida as well as Texas are thought to be connected to P. Vivax, and more likely originate in travelers who came from South America.
Symptoms and Treatments
Malaria can cause flu-like symptoms such as the body aches, fevers as well as vomiting and chills. It can be treated with effective antimalarials as well as IV fluids, but it’s important to recognize it in the early stages.
The most obvious indication of infection is the appearance of fever each couple of days. These are a part of the development of the parasite within the blood.
The residents of America U.S. needn’t panic, or even stay away from going out in hot and humid regions where mosquitoes flourish. It’s still important to be aware of the warning signs and potential risks. Srinivasan suggests: “If you have a fever, and they can’t figure out why you have a fever, [and] if you spend a lot of time outside where there’s a lot of heat and humidity, [malaria] should be considered, particularly because when you catch it early, you can treat it.”
If not treated, the illness could progress to extremely serious and even cerebral malaria. “Once you reach the cerebral malaria stage, even after anti-malarial treatment, [the] mortality rate can be as high as 20% to 25%,” Srinivasan states.
