Stronglyes

This post contains two pretty different Strongyles, one of which can have severe repercussions, the other of which is often asymptomatic. However, what connects them is that they both typically infect animals, they're pretty rare in humans, and human infections are typically found in Africa/the Middle East.

The first is a true strongyle (as opposed to our fake strongyle, Strongyloides), Oesophagostomum bifurcum. These can be found in pigs and ruminants all over the world, but the focus of their human infections seems to be in West Africa. They are called nodular worms because they produce nodule-like abscesses in the host's bowel wall.

They are quite robust little worms, up to 3cm, with eggs very similar to hookworms. They have a short, muscular, club shaped esophagus.

Photo Credit: wikipedia.com

Eggs will pass with the feces of the infected animal, then molt in the ground to become infectious. When the larva are ingested, they burrow into the large intestine, forming an abscess or nodule. The larva then spends approximately 2 weeks in the nodule. After it become an adult, it re-enters the lumen of the bowel and attaches to the mucosa.

This will present as appendicitis like pain. Notably there may be abdominal masses, which are caused by the nodule progressing out of the intestine and attaching itself to things around it, including the interior of the skin. In rare cases the nodule may even burst out of the skin.

Diagnosis can be made from eggs in the feces, which must be allowed to hatch so that they can be differentiated from hookworm eggs. The nodules are also a pretty big give away. Treatment is done with albendazole.

Photo Credit: stanford.edu

Trichostrongyles rarely infect humans, but when they do it tends to be in the Middle East. They're a common parasite of livestock. They are soil transmitted and adults live in the intestinal mucosa. They lack a buccal cavity, but they do have a well developed bursa, which makes them true stongyles.

They have a similar infection cycle to hookworms, though there is no pulmonary aspect. It's typically asymptomatic. Any sort of anti-helminthic drug will take care of it.