Nematode Zoonoses - OESOPHAGOSTOMIASIS

(Nodular Intestinal Worm Infection)

AGENT:

The causative agents are Oesophagostomum stephanostomum, bifurcum, and aculeatum.

RESERVOIR AND INCIDENCE

The parasite lives in the intestines of various primates and sometimes humans. These definitive hosts can sometimes serve as intermediate hosts. It occurs mainly in Africa, but occasionally in South America and Asia.

TRANSMISSION:

Eggs passed in feces release larvae which infect the definitive host on ingestion. The parasite invades the intestinal wall to form nodules. The fourth stage larvae which develop in these nodules migrate to the lumen of the large intestine to form the adult worm and complete the life cycle.

DISEASE IN ANIMALS:

Mild infection is subclinical. Abdominal pain follows more severe infection with diarrhea or even dysentery. Death in the NHP may ensue from perforation of the intestine and peritonitis.

DISEASE IN HUMANS:

Mild infection goes unnoticed but sometimes abdominal pain, and GI bleeding and even peritonitis occur. Granulomatous nodules in the intestinal wall contain larvae and parasites. These may be secondarily infected and lead to abscesses.

DIAGNOSIS:

Fecal flotation. Culture to obtain larvae for species ID.

TREATMENT:

Anthelmintic therapy.

PREVENTION/CONTROL:

Fecal screening of NHP's.  Wearing of protective clothing and gloves. Ensure good personal hygiene. Sanitary disposal of feces is important.