Researchers at pharmaceutical giant GSK, working underground at a biosafety level 3 insectarium in Madrid’s Tres Cantos, were frustrated.
The mosquitoes they were using to study their experimental malaria drug had a thorny problem. It had developed resistance to the parasite Plasmodium, the cause of an ancient disease.
“We needed to get this test up and running as quickly as possible,” said Dr. Janez Rodriguez, GSK’s scientific leader for global health drug research and development. “So we tried to find out the reason for this loss of sensitivity.”
The mosquito was found to carry a bacterium that secretes chemicals that inhibit the development of the parasite. This meant that the research team had to shut down the colony to study new malaria drugs, but it also found potential new ways to fight malaria.
The discovery published Rodriguez told Science magazine this month that further tests are currently underway in a field trip in Burkina Faso. The hope is that the bacterium, Delftia thulhutensis TC1, will one day become “a tool that could potentially be used in combination with existing strategies to achieve global malaria eradication,” she says. The co-authors wrote in a paper in the journal Science.
This approach is one of several new technologies being developed as humans battle mosquito-borne diseases for centuries. Other recent approaches include genetically modifying bugs so that they cannot produce viable offspring, gene drive It would wipe out their entire population.
I need new tools.Estimated number of deaths from malaria 600,000 In African countries where the disease is endemic, many people, mainly young children, are infected each year. Dr. Carolina Barillas-Murry of the National Institutes of Health says it’s so hard to fight there, and it’s hard for someone who’s never experienced it to imagine the burden of the disease.
“In endemic areas, when the rainy season comes, the infection rate is 300%,” said Bariras-Murry, director of the Malaria and Vector Laboratory at the National Institute of Allergy and Infectious Diseases. It says, “Everybody in that town will get malaria three times a year.” it never ends. ”
That’s why public health officials were so relieved this summer that eight local malaria cases were reported here, the first in 20 years, unless in a country like the United States.
“The risk is very low,” Dr. Peter McElroy, director of the Malaria Division of the Division of Parasitic Diseases and Malaria at the US Centers for Disease Control and Prevention, told CNN. Those cases are flag is up McElroy said the June outbreak did not lead to a widespread outbreak.
This was not always the case in the United States.
According to McElroy, in 1935 there were 100,000 malaria cases in the United States. In an effort to limit the impact of World War II in the southeastern United States, especially around military training bases, the United States created the Battlefield Malaria Service in 1942.
It then became the Center for Infectious Diseases, the predecessor of today’s CDC. The center was based in Atlanta, still home to the CDC, because malaria infections were most common in the south.
The tools used to control it today have improved, but adhere to many of the same principles.
Subsequent research “focused on both prevention and treatment,” McElroy said. “We wanted the program to deal with both mosquitoes and parasites.”
Preventive actions include draining standing water to eliminate mosquito breeding sites and installing screens in people’s homes, according to Dr. Daniel Murkowski, technical adviser to the American Mosquito Control Association. was said to have been included. The United States eradicated malaria in 1951.
“In the late 1940s and 1950s, all they could do was keep the population down to the point where they couldn’t effectively transmit malaria,” Markowski said. “But we have not eradicated all Anopheles mosquitoes.”
More than 200 species of mosquitoes live in the continental United States. according to Submitted to the CDC, about a dozen carry germs that can make people sick. Many have different characteristics, such as where they breed, when they bite, and how far they can travel.
Anopheles mosquitoes, which carry the parasite that causes malaria, tend to be “very prolific and very aggressive biters,” Markowski said. They are found across the United States, feeding at dusk and dawn and sometimes traveling miles a day to find food, he explained.
In Sarasota County, Florida, where seven of eight locally infected cases were confirmed this summer, targeting both adult and juvenile mosquitoes remains a challenge to contain malaria. mosquito control team sprayed Insecticides directed at adult mosquitoes were sprayed over 770 miles by truck at night, and swamps and canals were sprayed with so-called larvae to stop the adult mosquitoes early in their life cycle.
One of the big differences in control efforts today compared to 70 years ago was that work back then also included spraying indoor surfaces of homes with insecticides, especially DDT, Markowski said. said. This chemical is now rarely used. Harmful Health and environmental impact.
“DDT has been the norm for quite some time,” Markowski said. He applied it indoors, as well as outdoors, using trucks and aircraft, and “the mosquito population was sufficiently suppressed to eliminate malaria.”
However, because Anopheles mosquitoes live in the United States, the risk of transmission is also high. And about 2,000 cases of travel-related malaria are diagnosed each year in the United States, according to the CDC.
Until this summer, no local transmission had been detected since 2003. 8 cases It was discovered in Palm Beach County, Florida, a track record that CDC’s McElroy attributes to strong case detection.
“When people return from a country where malaria is endemic and they start showing symptoms, they complain to the health system,” he said. “The case is diagnosed, eventually treated, and then the case is first reported to the county and state health departments and ultimately to the CDC.”
It can be difficult for health care providers in the United States to know about suspected malaria. Its symptoms include fever, chills, headache, and malaise.the causative malaria parasite get infected The disease can be treated with drugs that destroy liver cells and red blood cells.
Malaria can cause serious illness if not treated promptly. Prior to the COVID-19 pandemic, about 300 people in the United States developed severe malaria each year, and five to 10 people died each year, according to the report. CDC data.
The CDC says a few things have to happen before a localized malaria epidemic is considered over: The most recent treated patient could be infected with a mosquito. A parasite disappeared, the mosquito that the patient might have infected died, and the patient was found with no new infections. Overall, it usually takes about 8-10 weeks after treatment is complete.
And although the tools are now better, there are several factors that could make the fight against malaria harder, AMCA’s Markowski said. He said modern mosquito control is usually a very localized effort, and states like Florida and New Jersey are very strong. Others are “something like hodgepodge”. This is a far cry from what the federal government did in the 1940s.
Markowski also suggested that heightened skepticism about public health efforts poses a new hurdle, especially since the COVID-19 pandemic.
“One of our biggest challenges is how to convince people that we are trying to help. It’s in our best interest to be able to enjoy it,” Markowski said.
Still, he and other experts said community transmission of malaria does not pose a significant public health threat in the United States.
“What worries more people in the United States is viral infections,” said Bariras-Murry of the NIH. “Zika, dengue, things like that.”
Approaches to these diseases spread by mosquitoes called Aedes aegypti and Aedes albopictus include newer techniques similar to a Delftia study published this month in the journal Science.
Verily, part of Alphabet, which is owned by Google, has a project called Verily. debug It uses a bacterium called Wolbachia on male mosquitoes to make them unable to produce offspring.
A company called Oxitec breeds male mosquitoes with a “self-limiting gene” that prevents offspring from surviving to adulthood. Both approaches use non-stinging male mosquitoes.Oxytec too To tell Research is underway to apply this approach to Anopheles mosquitoes as a measure against malaria.
Professor Bariras-Murry noted that the Delftia approach still needs further testing, but could contribute to more tools than ever before in reducing the burden of malaria.
“We’ve come a long way,” she said. “I am more optimistic than ever. It seemed absolutely impossible when I started 30 years ago…but now I think there are more options. I think I’m trying to become