New research has found a natural vaccine for malaria

When was the last time you had a sleepless night because of a mosquito flying around the room? A bloodthirsty mosquito bite in the middle of the night, and at any other time, is an unpleasant experience. As the Dalai Lama once said in his wisdom – if you think you are too small to change something, try sleeping with a mosquito next to you.

In Israel, apart from disturbing the peace of the night and some scratching, there is also a danger from the bite of female mosquitoes: in the past year, about 1,000 people were infected with West Nile fever, which is transmitted to humans through mosquito bites, and about 70 people died. In other countries of the world – mainly in tropical areas in Africa – the malaria parasite, which is spread by Anopheles mosquitoes, causes the death of 600 thousand people a year. Malaria was also common in Israel in the past, but efforts to eradicate it during the British mandate bore fruit. research Recently published offers a way to vaccinate against malaria – through mosquito bites.

which is fatal in malaria

“On average, a mosquito feeds on blood every three days,” explains Prof. Neta Regev-Rotsky, head of the laboratory that studies the biology of the malaria parasite, the Department of Biomolecular Sciences at the Weizmann Institute of Science. “There are countries in Africa where 50 percent of mosquitoes are infected with malaria, and in one night a child can be stung 40 times.” This, she says, is where the large numbers of malaria patients and mortality figures come from. According to her, every day in Africa 1,000 children die from malaria. half of the deaths occur in four countries that are considered the global epicenter of the disease: Nigeria, the Democratic Republic of the Congo, Niger and Tanzania.

One of the reasons for malaria being a deadly disease is the parasite’s ability to adapt to many living environments and many “storage” bodies such as various organs in the body of humans and mosquitoes. According to Regev-Rotsky, malaria is a severe fever caused by a parasite that lives inside our liver cells and from there passes into our blood cells. From the blood cells the parasite can return to the mosquito, and survive in its intestines or salivary glands – until it moves to the next human reservoir. In addition, the temperature changes between the human body (37 degrees Celsius) and the mosquito’s body (20 degrees Celsius) do not disturb the parasite. “he [הטפיל] knows how to live, survive, develop and flourish” in different incarnations and situations, claims Regev-Rotsky.

So far, two vaccines have been developed against malaria, which cause the human body to produce antibodies against the parasite. In the countries of Ghana, Kenya and Malawi it was registered Decrease in child mortality After one of the vaccines has been put into use. But these reach at best an efficiency of 75 percent, and require “booster” shots to strengthen their effect. Therefore, scientists continue to look for alternatives to reduce the damage of malaria.

think upside down

A group of researchers from the universities of Leiden and Nijmegen in the Netherlands engineered the genetic characteristics of the parasite that causes malaria so that it stops developing and multiplying after it has been transmitted to humans. According to Regev-Rotsky, the development of the parasite in the human liver depends on a certain type of protein. The researchers were able to engineer the parasite so that it neutralizes the activity of the protein in such a way that the parasite will not be able to develop in the liver, and will die.

The researchers examined the effect of the length of time the parasite was in the body before it died on the quality of vaccination against the disease. At first, the cessation of parasite development was planned to occur one day after human infection. Later, a longer duration of six days was also tested. During the experiment, three groups of experimenters who were bitten by mosquitoes participated. A first group was infected with transgenic parasites that stop developing within a day, a second group was infected with parasites that stop developing within six days, and a third group was bitten by mosquitoes that are not infected with the disease – this for control and comparison purposes.

Three weeks later, their condition was checked: at this stage, the groups that were bitten by infected mosquitoes had a higher level of antibodies compared to the situation before the bite. After that, all the experimenters were bitten by mosquitoes carrying non-transgenic parasites. The results are interesting: the first group – the parasite stayed in their bodies for one day – had only 13 percent protection. That is, the disease was not effectively prevented. The second group – in which the parasite stayed in their bodies for six days – had 89 percent protection – a more successful treatment than the existing vaccines. The third group had no protection at all.

Storage sting

The results of the study reveal an encouraging innovation: the improvement of the immune system’s ability to deal with the parasite is not only in the creation of antibodies, but during the long exposure to the presence of the parasite. One of the challenges that science has not yet understood regarding malaria, according to Regev-Rotsky, is how the parasite “works” on the immune system so that it does not develop Immune memory – The ability to recognize and respond to past infections. “In Corona, when you got infected – you had antibodies and memory in your body. Then the next time you get infected, it will be more weakened,” she explains. As for malaria, she notes, this was not the case. However, the experimental vaccine through a mosquito bite was able to strengthen memory retention. “That’s why the system [החיסונית] She started working properly – the parasite did not manipulate her.”

With the good news, Regev-Rotsky clarifies that the success of the experiment on a small sample of participants does not predict the success of the method among those who will need it the most: children in Africa. According to her, also from a technical and economic point of view there is a gap here that the researchers will have to solve. As part of the proposed solution, she notes, “we need a whole array of mosquitoes that feed on infected blood.” That is to say, the question remains as to how it will be possible to transfer the engineered parasite to the human body.

Regev-Rotsky warns that global warming is leading to the spread of the malaria-carrying mosquito population northward from the current malaria distribution areas. Therefore, even in our region and other western countries will have to use a creative solution to deal with the disease. “If there was such a disease in Israel, the United States or Europe – there would have been an effective vaccine a long time ago,” she says. Maybe malaria in Israel will stop being just an old story from the time of the establishment of the state, but at least there is a chance that there will be a vaccine against it; Thanks to scientists, and mosquitoes.