A microbe discovered by researchers in Kenya may provide a safe, biological way of fighting malaria. The mosquito-borne disease kills about 400,00 people every year.
Image: picture-alliance/dpa/P. Pleul
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Our headlines may be dominated by the spread of coronavirus, but malaria remains one of the main causes of death in developing countries.
The World Health Organization reports there were 228 million cases of malaria in 2018, and most of those infections were in Sub-Saharan Africa.
More than 400,000 people died during that period, most (67%) were children under the age of five. It's been said that due to supply chain problems caused by the coronavirus the number of deaths could double this year.
Malaria is transmitted to humans and other animals by female Anopheles mosquitoes when they "bite" and feed on the blood.
But a new discovery of a microbe in Kenya may have the potential to limit this spread of malaria, without causing much other chaos in the wider ecosystem. The microbe, or bug, which is found in mosquitoes, is thought to stop the transmission of malaria.
Researchers studied mosquitoes infected with the microbe, Microsporidia MB, and found that none of them carried the parasite responsible for malaria, Plasmodium falciparum. The researchers have published their findings in the science journal, Nature Communications.
More than 400,000 people die of malaria every year, mainly children under five. Image: picture-alliance/dpa/M. Mohammed
Scientists have been looking for naturally occurring microbes in mosquito populations in the hope of using them to eradicate malaria and other mosquito-borne diseases, such as dengue fever.
Microsporidia MB is a single-cell bug that lives in a mosquito's gut and genitals, where it produces spores. It is found in 5% of mosquitoes in a high-risk region around Kenya's Lake Victoria, where the researchers focused their work.
The researchers, who are biologists at the International Centre of Insect Physiology and Ecology (icipe) in the Kenyan capital, Nairobi, have suggested using mosquitoes infected with the microbe, or simply the spores it produces, as a natural agent against malaria.
Distribution of mosquito-borne diseases
Distribution of the Anopheles mosquito - carrier of malaria
Distribution of dengue fever - caused by the Aedes mosquito
Distribution of Culex mosquito - carrier of the West Nile Virus
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One way to do that would be to infect male mosquitoes with the bug in laboratories and release them into the wild, where they, the males, would pass the bug to female mosquitoes when they breed.
The researchers say at least 40% of a mosquito population has to be infected with the microbe in a given region for the method to be effective or significantly reduce malaria transmission to humans.
While other methods to control the spread of malaria, such as pesticides, aim to kill as many mosquitoes as possible, a biological method may have fewer knock-on, damaging effects for the surrounding ecosystem. The mosquitoes would live on as a vital part of the region's natural food chain.
Sharks and scorpions? The world's deadliest animals aren't what you thought
People are terrified of sharks but when you look at the number of people actually killed by them, you realize that the truly dangerous killers are others.
Image: AP
11. Sharks / wolves
People killed each year: around ten. Sharks and wolves scare many people. And there is no doubt that wolves and some shark species can kill you. But very few of them actually do. Each year there are only around ten deaths caused by either species throughout the world. You have a bigger chance of being killed by your toaster.
Image: AP
10. Lions / elephants
People killed each year: around 100. That you could be killed by a lion doesn't seem far-fetched and it does happen. Perhaps more surprising is that your chances of falling victim to an elephant are just as high. The world's largest land animal can be quite aggressive and once it becomes enraged, it certainly has the mass and strength to be dangerous.
Image: picture alliance / blickwinkel/D. u. M. Sheldon
9. Hippopotamus
People killed each year: around 500. There are countless children's toys in the shape of hippos and why wouldn't there be? They look cute with their puffy snouts and stocky builds. And they are herbivores. But don't let that fool you. They are territorial and quite aggressive and don't need provocation to come after you, so steer clear if you can.
Image: picture-alliance/dpa-Zentralbild
8. Crocodiles
People killed each year: around 1,000. Many people are probably just as scared of crocodiles as they are of sharks or lions and rightfully so. Crocodiles are carnivores and kill prey sometimes much larger than themselves including small hippos, water buffalo and, in the case of saltwater crocodiles, even sharks.
Image: Fotolia/amnachphoto
7. Tapeworms
People killed each year: around 2000. Tapeworms are parasitic flatworms that live in the digestive tracts of all sorts of vertebrates ranging from whales to mice, and humans as well. They usually find their way into our bodies as eggs or larvae via contaminated food. The infection can be treated with medication but the parasites still kill 200 times as many people as sharks do.
Image: picture-alliance/dpa/R. Loznak
6. Ascaris roundworms
People killed each year: around 2,500. Ascaris worms are another parasite contracted in a way similar to tapeworms. But they don't stay in the intestinal tract. Once the eggs hatch, they burrow through the gut wall, travel to the lungs, up the windpipe, are coughed up and swallowed again to return to the intestine where they grow into adults. Ascariasis affects around 1 billion people worldwide.
People killed each year: around 10,000. Tied in fifth place are three killers with a death toll of 10,000 each. Although to be fair, it's not the animals that are the killers here, but the parasites they carry. Schistosomiasis can be contracted from contaminated water, Chagas disease and sleeping sickness through insect bites. So make sure to bring bug repellant when you visit affected areas.
Image: picture-alliance/dpa
4. Dog (rabies)
People killed each year: around 25,000. Rabies is a viral infection that can be contracted from many different animals but in countries where rabies is common among dogs, humans get it from them in 99 percent of cases. And rabies is sneaky. It can take months for symptoms to show and when they do, the disease is almost always fatal. The good news is that both dogs and humans can be vaccinated.
Image: picture-alliance/ZB/B. Wüstneck
3. Snakes
People killed each year: around 50,000. Yes: In case of doubt, steer clear of snakes. Many species aren't deadly, some aren't venomous at all but there are enough deadly snakes to make these reptiles the world's third biggest killer.
Image: picture-alliance/dpa/blickwinkel/B. Trapp
2. Humans
People killed each year: around 475,000. Yes, we made the list, too. After all, we are incredibly creative when it comes to finding ways to kill each other. This earns us the sad honor of second place amongst the killers of man.
Image: picture-alliance/dpa
1. Mosquitoes
People killed each year: around 725,000. In places like Germany, they are just a nuisance, elsewhere they can be harbingers of death. And again it is the diseases they carry, not the animals themselves that kill. Malaria alone kills about 600,000 people a year. Dengue fever, yellow fever and encephalitis are transmitted by mosquitoes too, making the tiny insects the world's biggest killers.
