Introduction to Diagnostic Medical Parasitology
Adult worms of A. costaricensis inhabit the mesenteric arteries of the rodent definitive host, specifically the ileocecal area. Within these arteries, mature female worms lay eggs that travel through the bloodstream to intestinal wall capillaries. Here, larvae emerge and enter the lumen of the ileum. The initial-stage larvae are then expelled in feces and consumed by suitable gastropod intermediate hosts. After two developmental stages, they mature into third-stage (L3) larvae, which are infectious to mammals. When these gastropods are ingested by the definitive host, the L3 larvae move into the lymphatic vessels within the abdominal cavity, developing into adult worms. Some L3 larvae may also be released into the environment by snails through slime trails, although the significance of ingesting these larvae as a transmission route remains uncertain.
Upon ingestion of raw or undercooked gastropods containing L3 larvae or food items contaminated with gastropod tissue or larvae potentially present in slime trails, humans can become infected. In humans, the larvae follow their typical migration, potentially reaching sexual maturity and producing eggs, unlike A. cantonensis. The presence of larvae, adult worms, and eggs triggers a local inflammatory reaction in the intestinal wall. This immune response often leads to the degeneration of parasites and eggs, and eggs are not typically detected in human stool.
- Parts of Latin America and the Caribbean
- Has been found in various animals in the southern United States
- Sporadic human cases identified in the United States are thought to have been travel associated
Arise from the parasite’s invasion of the gastrointestinal wall
Can mimic those other conditions:
- Crohn’s disease
- Meckel’s diverticulum
- Eosinophilia is commonly noted
Ectopic infection (e.g., in the liver)
- Intestinal obstruction
- Other complications may occur
Detecting abdominal angiostrongyliasis (A. costaricensis infection) involves identifying eggs, larvae, or adult worms in histologic sections. Considering the patient’s travel or exposure history may lead to the consideration of this diagnosis.
There are currently no specific molecular tests available for A. costaricensis. However, conventional PCR followed by DNA sequencing analysis can be utilized to identify A. costaricensis in tissue samples.
Method: Western Blot
Prevention and control
Thorough Cooking: Ensure that gastropods (snails, slugs) are cooked thoroughly before consumption to kill any potential larvae. Avoid consuming raw or undercooked gastropods.
Proper Food Handling: Be cautious when handling food items that may have come into contact with gastropods. Avoid cross-contamination by using separate cutting boards and utensils for raw and cooked foods.
Washing Produce: Carefully wash fruits and vegetables, especially those that may have been in contact with gastropods, to eliminate any possible larvae or slime residue.
Personal Hygiene: Practice good hand hygiene, especially after handling gastropods or working in areas where they are present. Wash hands thoroughly with soap and water.
Educational Awareness: Increase awareness among communities or individuals regarding the risks associated with consuming raw or undercooked gastropods.