Trichuris trichiura Eva Dali & Quinn Quaderer The Human Whipworm

Taxonomy Kingdom: Animalia Phylum: Nematoda Superphylum: Aschelminthes Class: Enoplea Order: Trichinellida Family: Trichuridae Genus: Trichuris Species: Trichiura

Some interesting facts T. vulpis is an important whipworm for canids including dogs, foxes and coyotes; Common in the U.S. except in drier areas T. suis is important for swine and is indistinguishable from T. trichiura Whipworm is a Soil-Transmitted Helminthe Eggs of T. trichiura were found in a glacier mummy more than 5000 years old In 2010, the estimated number of persons infected was 604-795 million

GEOGRAPHIC DISTRIBUTION Worldwide Two conditions are necessary Poor standards of sanitation-Human feces on the soil Physical conditions that allows eggs development and survival; Warm climate, high rainfall and humidity, Moisture-retaining soil, dense shade

MORPHOLOGY The eggs are lemon shaped with an opercular plug at each end. Contains single celled zygote. 2-cell stage before advanced cleavage stage Adults look like a whip; anterior 2/3 thread-like, posterior 1/3 club-like.  Females are longer than males, males  have a corkscrew tail, and both sexes have a stichosome esophagus

Trichuriasis Life Cycle

LIFE CYCLE This is a direct life cycle. Adult whipworms are found in the large intestine, usually the ileocecal area.  They mate and the eggs leave the body in the feces.  They must embryonate before they are infective, which takes about three weeks.  Infective eggs are ingested from eating contaminated soil. Upon ingestion, the larvae hatch and penetrate the small intestine to mature.  They eventually migrate to the large intestine and complete maturation in three months. Adults can live for years and deposit thousands of eggs per  day.

Pathology Light infections (<100 worms): Usually asymptomatic Moderate to heavy infections: affect cognitive function in children and finger and toe clubbing Intense trichuriasis: dysentery, anemia, growth retardation, finger clubbing and rectal prolapse

Microscopically detecting worms or eggs in stool Diagnosis Microscopically detecting worms or eggs in stool

TREATMENT AND CONTROL Sanitation: use of toilet facilities and safe disposal of feces Health education Mass treatment in communities with high prevalence DRUG OF CHOICE Mebendazole Albendazole

PUBLIC CONCERNS Whipworm is the third most common nematode infection in humans behind Ascarids and human pinworm (E. vermicularis).

References Janovy, John. Roberts, Larry. Gerald D. Schmidt & Larry S. Roberts’ Foundations of Parasitology, 8th edition. New York: McGraw Hill. 2009. CDC: http://www.cdc.gov/parasites/whipworm/gen_info/index.html http://www.parasite-diagnosis.ch/web/11113/trichuriasisclinic

Questions Humans get infected from ingesting contaminated plants. T/F Poor standards of sanitation and cold climate are conditions necessary for the development and survival of eggs T/F Adult Trichuris trichiura is found in the small intestine. T/F The egg is pear shaped T/F There are less than 100 worms in an infected human. What symptoms would be seen?