Tag Archives: gross
Ascaris Lumbricoides is the prototypical large round worm of humans. This is the human worm of folk lore, having a propensity to wander at times and is known to occasionally exit the body through any orifice that has connection with the small intestine. In addition it can reach impressive sizes, with females reaching a length of 19 inches. Ascaris lumbricoides is estimated to live in the gut of up to ¼ of the people in the world. It can live in this incredible number of people because it is a relatively passive parasite. It lives freely in the small intestine for most of its lifecycle, feeding on nutrients within the small bowel, and not invading human tissues in its adult form, nor attaching to the gut wall.
Ascaris also has one of the more complex life cycles for a parasite with a single host. The infection is contacted when the egg of the organism is ingested. The egg hatches in the human duodenum, where the larval worm penetrates the wall of the duodenum and enters the blood stream. It passes through the liver and enters the venous circulation. The larval worm passes through the heart and into the pulmonary circulation where the wedge in the pulmonary capillaries. They then penetrate the alveoli, the tiny lung air sacs, and are expectorated and swallowed. They return to the small intestine where they mature until the male and female worms can mate. The female then continues to grow and can produce up to 200,000 eggs per day for about a year. The eggs are passed in the stool, and in areas where hygienic disposition of human excrements is not routine, the eggs can be deposited into the soil. They have a tough covering, can survive many years and if ingested the cycle is started over again.
Understanding the life cycle of Ascaris Lumbricoides makes it clear why round worm infestation is especially prevalent when human feces is used as fertilizer. The resilient egg can be ingested on the very foods that the fertilizer is used to grow. Public health measures try to focus on education about the danger of this practice.
Treatment of Ascaris Lumbricoides is fairly simple. The same medication that is used to treat Enterobius vermicularis the common pinworm is very effective at killing these worms. After treatment vast quantities of worms can be passed in the stool, and impressive photos of the results of treatment are noteworthy.
When the worms are stressed, either from toxic foods ingested, or from lack of nutrients they may wander from the small intestine, and photos of the worms exiting their human hosts are among the most startling parasitic photos we see. These are big worms, not a microscopic diagnosis in these situations.