Asacaris lumbricoides
![](https://parasiteguide.libbymitchell.dcreate.domains/wp-content/uploads/2021/05/Ascaris.gif)
Morphological Characteristics
This worm is round and tapered at either end. Females are larger than males. Males can grow to around 31 cm and females can grow to 49 cm. There is one dorsal and ventral lips.
Identification Methods
Stool samples are taken and studied with microscopy for eggs. Often times the hosts do not show any symptoms, but with larger parasitic loads they can have respiratory issues, anorexia, nausea, diarrhea, abdominal masses, or pancreatic issues.
LIFE CYCLE
- Adults live in lumen of human small intestine
- Female produdes eggs which are passed to the environment through feces
- Larvae become infective after around 18 days
- A human ingests the eggs which are now infective. This is typically happens as a result of poor hygienics and hand to mouth contact
- The larvae hatch within the new human host
- They circulate to the lungs
- The larvae mature for about 10 days in the lungs and are then coughed up and re-swallowed, which allows them to enter the gastrointestinal tract
- They reach the small intestine and the cycle begins again
*life span= 1 to 2 years
HOST INFORMATION
- Very similar to Acaris suum, which infects pigs, so pigs may be the reservoir host
- Transmitted human-human via oral-fecal route
- Eggs survive best in warm humid areas because they must grow in the soil before they infect humans
- People who live in close proximity to pigs are at a higher risk
- Most cases occur in tropical and sub-tropical areas of Asia, sub-saharan Africa, and the Americas
- The infection is treated with antihelminthic drugs, which remove the parasites within a few days
GEOGRAPHICAL DISTRIBUTION
Transmission can happen anywhere in the world, but majority of cases occur in tropical and sub-tropical areas of Asia, Sub-Saharan Africa, and the Americas.
SOURCES
https://www.cdc.gov/parasites/ascariasis/biology.html
https://my.clevelandclinic.org/health/diseases/15240-roundworms
https://biologyeducare.com/ascaris-lumbricoides/
http://web.stanford.edu/class/humbio103/ParaSites2005/Ascaris/JLora_ParaSite.htm