Humans evolved in the presence of the parasitic worms, and immune response was educated in these parasitic worms. Ecologist Kevin Lafferty said there are more than 100 human-specific parasites. Lafferty says parasites are the most common way to live on planet Earth. Science usually focuses its efforts on searching for what he calls free-living species. In the bird, the parasites grow new until it goes number two again, and then the cycle repeats. Most of the parasites are worms.
Parasite probably blood-sucking worms and disease-carrying microorganisms. They have very definition survive by living off a host at the host’s expense. In many cases, they can weaken and ultimately kill the host. The parasites might not always be bad news. In certain circumstances, they can be harnessed to serve more honorable purposes altogether.
Are some parasites good for you?
The idea of using parasites isn’t a new one like the humble leech. It’s a real bloodsucker attaching itself to anything fleshy that comes its way. It is good for the leech but not so good for the unwitting animal as they risk the effects of blood loss and infection of open wounds. But bring the leeches into a more sterile setting. These suckers can do much more good than their replication suggest.
Though it might sound pretty gross, leeches are now being used in the operating theatre to keep blood flowing during plastic and reconstructive surgery. When body parts are attached, surgeons find it easy to get the blood flowing through the arteries but not so easy to hook up the veins to get it flowing out again. When it bites down, it injects a powerful chemical that stops blood clotting. The wound can bleed for hours and hours, preventing blood from pooling and damaging tissue and giving the veins time to heal.
In Western countries, at least improved hygiene and sanitation seriously reduced the amount of inspection by the parasitic worms. A rise in bowel disorders has accompanied the rise of domestic hygiene. And some think it’s the loss of helminths at the root of the problem. The theory goes that as the worms wriggle through the body, they damage the tissues, which triggers a particular kind of immune response.
The immune system continually fix the damage the worms cause and reduces inflammation, protecting against these unpleasant and painful bowel diseases. So-called Hellmann’s therapy is being researched and developed at the moment.
They have promised, but there’s a long way to go before scientists fully understand the impact and benefits of parasitic worms. And hopefully, find a way of using them without having to eat the worms or let them crawl through the skin. The parasites are useful more than human health. Insects are not immune to parasitic infection.
Parasitic wasps can target fellow insects and lay their eggs inside them. When the larvae hatch inside the insects’ body, they have already prepared a Goulet meal of insect innards to eat before facing the world. The more of these murderous larvae, the fewer insects. So the parasites can and have been used to control insect populations.
A Phidias curve eye attacks a Fedeli eat crops which keeps farmers from having to use pesticides. The researcher thinks infecting humans with hookworms might cure them. Helmets are small worms. Some research suggests that once inside the body, these tiny worms cause anti-inflammatory responses in humans and even flick a switch in the immune system. They’ve used worms to anecdotally cure chronic diarrhea, all sorts of colitis, and other stranger things. Even leeches are used to draw blood and help skin grafts.
There are even symbiotic relationships between two organisms. The red-billed oxpecker sits on the backs of larger animals in sub-Saharan Africa and eats the ticks biting through the larger fellow skin, which is pretty nice.
Benefits of parasites
In Thailand in 2010 when an outbreak of mealy bugs threatened the local cassava crop. Instead of using pesticides, nearly a quarter of a million parasitic wasps were unleashed to target the unwanted bugs with great success specifically. And killing off insect pests isn’t all these parasitic wasps are useful for. With a high-tech twist, they can even be used to detect drugs.
The small stingless micro plight is Crockett’s wasp usually use their antennae to track down their favored caterpillar hosts. By sniffing out a chemical in their poo. But scientists have managed to train them to track down an entirely different chemical that doesn’t lead to a host but illicit drugs.
By harnessing these insect instincts and containing the wasps in a portable device, the wasp hound was born to sniff out drugs, explosives, and even bedbugs. So while there’s no doubt that parasites can still live up to their gruesome reputation with a bit of control and plenty of imaginative thinking, they might just be able to redeem themselves.
Parasites don’t cut most of our favorite creature lists. That’s because we don’t know about the crucial and surprising roles they play in the ecosystems. Tiny parasitic worms need to make their way from land to water to mate. To get there, the worm infects crickets and prompts them to fling themselves into streams.
The sacrifice delivers the worm to water, and the unlucky crickets provide up to sixty percent of the endangered fish’s food supply. Parasites like this one may be critical to the functioning of many ecosystems. But they have historically been left out of the maps scientists create to help understand the flow of energy through a habitat.
Ecologists have built hundreds of food webs. In the salt marshes of Southern California, a trematode worm moves from one host to another as it develops, living in snails as larvae and reproducing only in the gut of shorebirds. It makes the transition through an unusual route: The brain of a fish. Fish with parasites on the brain are more likely to flash their silvery bellies toward the sky, a beacon to hungry birds overhead. The result: Infected fish are up to 30 times more likely to get caught, delivering the parasite to its final avian home.
Parasites may regulate population numbers by feeding on their host species and competing with others for food. In the few cases where parasites have been added to food webs, the enhanced complexity is obvious. Some parasites even benefit humans directly.
Source: Borgsteede FH. The effect of parasites on wildlife. Vet Q. 1996;18 Suppl 3:S138-40. PMID: 8933697.