Fever-stricken patients who come to hospitals should be checked for malaria, health officials say, even if they have not recently left the United States.
Alarms have been raised about five cases of the disease — four in Florida and one in Texas — appearing to have originated from local mosquitoes. They point to the possibility that malaria has returned to the United States.
The Centers for Disease Control and Prevention (CDC) issued a health alert on Wednesday urging doctors to watch for more cases.
Experts say the cases were likely isolated, but warned another mosquito-borne disease could reach the US within a decade. They said global warming allowed the mosquito population to expand and reach new areas.
Experts warn mosquitoes are on the rise in the US and there is a risk another mosquito-borne disease could reach the country within a decade (stock image)
The CDC issued the warning yesterday, saying doctors should still “routinely consider malaria as a cause of febrile illness in patients with a history of international travel to areas where malaria is transmitted.”
But they added: ‘clinicians should’ [also] consider a malaria diagnosis in any person with a fever of unknown origin, regardless of their travel history’.
The five cases of malaria diagnosed in the US have all been reported in the past two months and are the first cases since 2003.
Health officials fear there may be others in the community, but are being misdiagnosed as other illnesses.
Malaria was eradicated in the United States in 1951 following a massive public health program that sprayed pesticides from airplanes onto mosquito breeding grounds and removed potential breeding grounds for the insects.
But since then, sporadic cases have repeatedly surfaced – although these have not led to wider community transmission.
These were probably sparked after a human infected with malaria but showing no symptoms came to the US and was bitten by a local mosquito, which became infected. When this insect bit another human, it passed on the disease. It may also have arrived in malaria-infected mosquitoes stashed on an airplane.
Early warning signs of the disease include fever, chills, headache, muscle aches, fatigue, and nausea.
Without treatment, these can develop into complications such as anemia – a low red blood cell count – and organ failure, which can be fatal.
Dr. Thomas Moore, an infectious disease expert at the University of Kansas, warned DailyMail.com that he expected malaria to become more prevalent in the US in the coming years.
He said, “I think it’s fair to say that given global warming, we’re probably going to hear about these cases a little more often.”
He said malaria would likely follow other diseases, such as dengue fever.
“With malaria comes dengue,” he said, “which almost goes hand in hand with malaria because they cover the same areas.”
Dr. Jason Rasgon, a mosquito expert at Penn State University, said there are occasional cases of malaria in the United States and this was no different.
“This happens every now and then,” he said.
Dr. Thomas Moore (left), an infectious disease expert at the University of Kansas, warned that the mosquito population was on the rise. Dr. Jason Rasgon, a mosquito expert at Penn State University, said more mosquito-borne diseases could reach the US
He explained how the latest cases probably originated, adding: ‘Someone came in somewhere with malaria – probably an asymptomatic carrier.
“Some local mosquitoes picked up on this and bit other people, causing disease.
“This has been recognized for some time. But I don’t think it’s anything to worry about.’
Both experts warned that global warming could allow mosquitoes to spread to new areas and increase the risk of bringing more disease.
The warmer weather led to heavier rainfall, and as a result, more stagnant pools of water were available for mosquitoes to breed in.
It also sped up their life cycle and meant their eggs could survive the winter further and further north, allowing them to disperse.
Dr. Rasgon said it was likely that another mosquito-borne disease would emerge in the US within the next decade.
He said this was caused by a “perfect storm” of an interconnected world, which made it easier for disease to spread from one area to another.
He said it can be brought in by infected mosquitoes stashed on an airplane or by an asymptomatic human who then passes it on to the local mosquito species.
The US already has several mosquito species that can transmit malaria, increasing the risk of the disease establishing itself here.
In the past two decades, three new mosquito-borne diseases have been identified in the US. West Nile virus reached the country in 1999 and was followed by Chikungunya virus, in late 2013, and Zika virus, which emerged in 2016.
Malaria is a potentially life-threatening disease contracted when a mosquito introduces a parasite into someone’s bloodstream.
It can be treated with antimalarial drugs that target the parasite, such as hydroxychloroquine, previously touted by Donald Trump as a cure for Covid.