In late May, health officials in Sarasota County, Florida, confirmed they had confirmed a locally transmitted case of malaria.of Mid-June, they confirmed the second. On June 23, the state of Texas joined in, the Texas Department of Health announced a confirmed case of localized malaria in Cameron County.
All this is very unusual. The United States has not recorded a domestically acquired case of malaria. 20 years.
About 2,000 Malaria infections appear in the U.S. healthcare system each year, but all of those cases are associated with travel outside the United States. None of the people involved in the Florida and Texas cases had any travel history. This means that both states were infected within the borders of the United States.
Experts say the three cases need not cause panic about the malaria epidemic in the United States. However, it is natural to have some questions and be wary of the threat of further local infections. More cases are likely, as mosquitoes can infect multiple people before a full-blown epidemic is identified.
Even if this doesn’t turn out to be prevalent, this will be a good reminder. Malaria could strike again in the United States, and we, and the public health infrastructure, need to be prepared. This is especially true as climate change and weather pattern changes become more and more acute. movement of mosquitoes It invades new places around the world, allowing malaria to colonize places it has never colonized before.
These cases are not the worst form of the disease, but they are not benign
There are many types of malaria, all of which belong to the Plasmodium genus., Any parasite that infects and kills red blood cells. The resulting anemia accounts for most of the body’s subsequent havoc.
The species identified in both Florida and Texas is P. vivax.. Not the Worst Species of Malaria: Plasmodium falciparum, The most severe form of malaria is 10 times more deadly than Sanman diseaseTreatment of vivax is not straightforward, according to a study of Americans diagnosed between 1985 and 2011. Having this infection can lead to life-threatening brain swelling, lung congestion, and kidney failure.
Infectious disease causes recurrent fever. wide range of symptoms It can be mistaken for flu, gastroenteritis, or liver disease.
vivax malaria is more vile than other malaria. The parasite remains dormant in the liver for years after the initial infection and remains awake long after exposure. (World wide, most of the vivax malaria infections occur in East Africa, South Asia and northern South America. )
Malaria used to be a big problem in America. eradicated in the 1950s, primarily by spraying homes and environmental areas with the insecticide DDT to kill the mosquitoes that spread it. (Although all forms of malaria are spread by Anopheles mosquitoes, they continue to infect the United States. a lot one of them. )
Also prevents malaria: The mosquitoes that carry this disease prefer to bite at night. Also, American households are increasingly installing window screens and air conditioners, and people in the home are better protected from being preyed on by this genus of mosquitoes.
So malaria is no longer expected to hit the United States. But if things go well, we have all the ingredients for malaria transmission in the United States.
What does it take for malaria transmission to occur in the United States?
One of the great unanswered questions at this time is why are two geographically separated regions of the United States now experiencing localized transmission of malaria, especially after many years of malaria-free history? The question is whether there are
Both states experience high numbers of travel-related malaria cases each year, but these cases typically do not lead to local epidemics. Will anything be different this year? Or is this just a coincidence?
To consider the possibilities, it helps to understand how malaria spreads.
Malaria infects female Anopheles mosquitoes bite an infected personAnd after a week it bites an uninfected person. Between bites, mosquitoes do their job in warm, stagnant water, but they are picky about water they prefer. Sarasota County Mosquito Manager Wade Brennan wrote in an email that these malaria-spreading mosquitoes generally prefer to breed in vegetated bodies of water along banks. In other words, they prefer forests to puddles near human settlements, such as those found in empty buckets and trash cans outside their homes.
To initiate local transmission, a person infected with vivax malaria abroad needs to be close enough to the Anopheles mosquito habitat where they can be bitten.. For the next few days, vivax virus infection multiplies in the mosquito’s gut. After about a week, it will be ready to infect others. When the mosquito bites its next victim, the particles in its saliva mix with the person’s blood, and some of the particles are injected into the person’s body before the mosquito releases it.
A few weeks later, the second person becomes ill. Meanwhile, the mosquito still has weeks to live. In the meantime, you can smoke other people and become infected. But even if they die, their companions can still bite the newly infected person and spread the infection.
Thus, the basic components of malaria transmission are the source of infection (infected returning travelers), the vector (mosquitoes), the uninfected target (newly confirmed cases), and the contact they are able to make. It is an environment that makes An increase in any of these factors may make localized infections more likely.
A robust public health system can help us understand the causes of such cases and is essential in responding.
It is not yet clear whether changes in mosquito populations or changes in human behavior are responsible for the current spike in cases in the region. However, public health studies in both states have already identified risk factors for infected individuals and sources of infection in the environment.
Epidemiologist Michael Drennon of the Sarasota County Health Department could not share demographics or location information about the two locally infected people. However, he noted that both are adults who spend a significant amount of time outdoors at night and have not traveled outside the United States. A representative of the Texas Department of Health said the confirmed case in the state was an adult who worked outdoors.
Brennan said the Sarasota County mosquito control team found malaria-infected mosquitoes in wetlands and focused on prevention by spraying the area with insecticides that kill both adult and juvenile mosquitoes. rice field. “We were able to confirm that the mosquito population in the area was extremely low,” he wrote.
It is unclear whether more Anopheles mosquitoes are circulating than normal in either state. As mosquitoes proliferate, the parasites of infected people are more likely to spread to uninfected people, making the disease more difficult to eradicate.
Overall, the U.S. environment is predisposing to increased mosquito populations, which may increase the risk of malaria transmission. climate change Estelle Martin, an entomologist at the University of Florida Gainesville who studies mosquito-borne diseases, said mosquito-borne diseases were widespread across the United States and “clearly involved in vector-borne diseases.” . Over the past two decades, warmer temperatures and extreme weather events have increased mosquito breeding, which in turn has increased the breeding of malaria parasites. However, it is not clear exactly what role the dynamics play in these three cases.
A spokeswoman for the US Centers for Disease Control and Prevention wrote in an email to Box on Friday: So. “More likely is the power of immigration,” officials said. Being able to be transmitted by local mosquitoes and ticks was ‘common’ in some places. ”
It’s not the time to panic, but it’s time to protect yourself
Even if a few people are infected and there are a few mosquitoes with worms in their stomachs, that doesn’t mean the United States is headed for an explosive malaria epidemic. “It’s always worrying when there’s an outbreak in the community,” Martin said, adding there’s no need to panic. And there are many things people can do to protect themselves.
Drennon said it’s important to do your best to avoid mosquito bites. He advises people to wear long sleeves and cover their legs (which he admits is difficult in the Florida heat) and to use mosquito repellent.
Eliminating mosquito harbors is also very important. Anopheles mosquitoes don’t typically congregate near homes, but other mosquitoes are infested, so people are advised to drain standing water and eliminate areas where water is prone to pooling. Other infections You can breed there. “It’s not uncommon to have dengue fever here,” he said. During the 2016-2017 Zika epidemic, the state was also one of two locations in the United States where the virus was infected. sent locally.
It is also important that local health care providers are aware of local malaria risks. Mosquitoes can infect multiple people before an outbreak is identified. So, once an infected person is found in one of hers, public health officials must act immediately, alert health workers, educate the public on prevention, and coordinate missions to find and kill mosquitoes. .
The first case in Sarasota County was first diagnosed when the patient was being tested for fever. Drennon said an abnormal blood test necessitated further testing. Local health care providers were alerted to this case, and her second case was reported shortly thereafter.
Even if these epidemics prove to be temporary, the threat of stronger malaria persistence in the United States remains. “We know there are people who have traveled all over the world and could get malaria here,” Drennon said. “And we know there are vectors here to transmit it.” ‘ is important to the people.
