The Hookworm is a type of nematode that attaches to the small intestine of its host mammal. There are usually two that feed on humans, although there are many other types that affect such species as dogs, cats, horses etc. There are even some species that can infect fish and other sea creatures such as seals and whales.
The species that commonly feed on humans are called Ancylostoma duodenale and Necator americanus. The latter getting its name because it was originally common in many parts of both North and South America, where the other tends to be more prevalent in North Africa and India. Both species are most common in warmer climates and are fairly rare to encounter in colder climates because their first stage of life is on the ground in warm sandy soil.
The Ancylostoma duodenale is most commonly ingested into the body where the Necator americanus usually penetrates the skin from he ground to enter the body through the soft skin on the foot.From entering the body they travel through the bloodstream towards the intestine. They can find their way because they can detect the nutrients that they need and follow the flow of blood ever towards this until they are in the intestine. Here they attach themselves to the wall and begin to absorb nutrients through the food we eat as well as our blood. Their eggs are laid in our intestines or gut as well, and they pass through our system into our feces, where they leave the body and their life cycle begins again.
They are also a lot more common in poorer or developing countries as a lot of more developed countries have undertaken eradication programs that has very nearly wiped them out in a lot of countries where they were once common. For example Southern Europe and certain warmer states of America used to have a lot of cases but now have extremely few because of mass screening and efforts to destroy the populations of the worms, at all stages of their life cycles.
Places where these eradication programs cant be afforded are still rife with the worms, and travelers frequently catch them as well. because the hook worm is a parasite and tends to spend as little time outside of the body as possible, it is not an important link in the food chain. This is because when it is outside of the body it stays buried and usually dies in a few weeks anyway, or if exposed to the sunlight or hot temperatures.
Because they are passed out through the feces it is important to only defecate in proper toilet facilities. In many poorer countries where toilet facilities aren’t available people are forced to defecate on the ground, which lets the eggs of the hookworm pass into the soil. This is how the infections are passed between people. If you use only proper facilities whilst on hvacation then you have much less chance of catching hook worms or passing them on to someone else if you already have them.
Although they in themselves aren’t usually dangerous, if enough of them can develop unchecked then they can eventually cause Anemia because they suck iron, blood and other nutrients from the foods we eat. Other than this there is usually no other discernible symptoms, particularly in the early stages so diagnosis is often difficult to make. The one more dangerous place they may be prevalent is in expectant mothers, where they can cause the baby to be born malnourished, underweight and even underdeveloped. Hookworms in fact are one of the biggest causes of infant mortality in developing countries.
There are several treatments available however as well as there being easy ways to avoid infection. Firstly always wearing shoes when walking around in sandy warm soil is the best method of avoiding them. Note this is sandy soil and not pure sand as on a beach, where they don’t survive as well because of there being a massive number of other species that will eat them in the sand and on the shoreline. Secondly always digging a pit for use as a latrine if circumstances require it, rather than defecating on the surface of the soil where the worms can easily make their way over the ground to infect more people.
As more and more countries become more developed and scientifically advanced we will probably soon see a global effort to wipe out both species forever all over the world. Meaning they will only be able to exist in isolated communities such as tribal communities etc and in general should never be able to affect most people again.