Up to 19% of the human population would have been exposed to the Toxocara parasite according to a new analysis that led to a study published in PLOS Neglected Tropical Diseases. The Toxocara parasite can also cause toxocariasis in humans.
This small gastrointestinal nematode worm is one of the most present and widespread in domestic dogs and cats and can also spread in the human body in the form of larvae when people come into contact with Toxocara canis or Toxocara cati larvae.
The faeces of these animals are in fact found everywhere, sometimes even in the street or in public parks, and coming into contact with the eggs of these nematodes is unfortunately more than easy. To favour even more the diffusion are the insects, in particular the flies, which nourish of the faeces of these animals and which then lean on other surfaces or even the food.
Once infected, the disease can see several symptoms including migraine, fever, cough and abdominal pain. In more severe cases it can lead to other symptoms including allergic skin disorders and asthma. The parasite can get to infect, is believed to migrate through the optic nerve, even the eye and create damage to the eye system. Children, especially those living in poverty, are among the most affected.
In most cases, toxocariasis resolves itself and often the people affected, apart from some headaches or stomach pain, do not even know that they have been exposed or infected. This is because Toxocara larvae cannot mature inside the human body.
In this new study, researcher Ali Rostami, with the help of colleagues, has analyzed 250 previously published studies on the prevalence of these infections or on the exposure of humans to Toxocara. In total all the studies concerned data from 265,000 people from 71 countries.
The results show, according to the researchers, that 1.4 billion people worldwide, or 19% of the entire world population, were exposed to Toxocara. Of course, the rates vary from region to region and the highest rates are those for Africa and East Asia while the lowest are those for Europe and the Eastern Mediterranean.