Ascaris is a genus of parasitic roundworms that belong to the phylum Nematoda. These worms are commonly known as intestinal roundworms and are known to infect humans and a variety of other animals. The most prevalent species within this genus that infects humans is Ascaris lumbricoides.
Ascaris lumbricoides is the largest intestinal roundworm that infects humans, with females growing up to 35 centimeters in length, while males are slightly smaller at around 25 centimeters. These worms have a cylindrical shape and are pink or white in color. Female Ascaris worms are capable of producing a large number of eggs, which are excreted through the feces of infected individuals.
Humans can contract Ascaris infections ingesting eggs present in contaminated soil, water, or food. Consuming food grown in soil fertilized with human feces is a common way of contracting the infection, especially in regions with poor sanitation practices. Once the eggs are ingested, they hatch in the small intestine, and the larvae penetrate the intestinal wall, entering the bloodstream. From there, they travel to the liver and then to the lungs.
In the lungs, the larvae penetrate the air sacs and undergo further development. They eventually migrate to the throat, where they are swallowed and return to the small intestine, reaching maturity. Once in the intestinal lumen, the adult worms mate and produce eggs, which are then excreted in the feces, completing the lifecycle.
The symptoms of Ascaris infection can vary depending on the number of worms present and the immune response of the infected individual. Many infected individuals may be asymptomatic, especially in light infections. However, in heavier infections, symptoms may manifest, including abdominal pain, diarrhea, nausea, vomiting, weight loss, and malnutrition. In some cases, the worms can obstruct the intestinal tract, leading to intestinal blockage and other complications.
The diagnosis of Ascaris infections is often made through the examination of stool samples, where the presence of characteristic eggs can be observed under a microscope. In some cases, imaging techniques such as X-rays or ultrasound may be used to detect the presence of adult worms or complications associated with the infection.
Treatment of Ascaris infections typically involves the use of anthelmintic medications, which are drugs specifically designed to eliminate parasitic worms. Commonly prescribed medications include albendazole, mebendazole, and ivermectin. These medications effectively kill the adult worms, preventing further egg production and interrupting the lifecycle of the parasite. In severe cases, surgery may be required to remove blockages or other complications caused the worms.
Preventing Ascaris infections primarily involves improving sanitation practices and personal hygiene. This includes practicing proper handwashing techniques, ensuring the consumption of properly cooked food, and avoiding the ingestion of soil or water that may be contaminated with Ascaris eggs. In regions where the prevalence of Ascaris infections is high, community-wide deworming programs may be implemented to control the spread of the parasite.