PlatyhelminthsTrematoda (Flatworms)

Flukes

Flatworm unsegmented body No body cavity; nutrients diffuse across body surface

=acoelomate >11,000 species Affect >300 million people each year (mostly in Africa and Asia) Most are obligate parasites

Live in intestines, tissue, or blood Distinctive mouth part (sucker)

Intermediate stages are asexual whereas adults are either male or female

Complex life cycle

Facts about Flukes

1. Intestinal Fluke2. Liver Fluke- this species actually eats your

liver and blood causing problems with fat metabolism and systemic inflammation.

3. Blood Fluke- causes infection in the blood that can cause fever and also can spread throughout the bloodstream to affect other organs and glands of the body.

4. Lung Fluke

Different kinds of flukes

Responsible for Schistosomiasis

considered by WHO as the 2nd most socioeconomically devastating parasitic disease (after malaria)

the worms are not found in US >200 million people are

infected worldwide. one of the NTD Parasitic larvae live in certain

types of freshwater snails.

Shistosoma: Blood Flukes

Life Cycle Male and female adult

worms Eggs released in bladder

or intestines excreted w/ urine or

feces to fresh water Larvae pass through

intermediate host = snail Larvae can survive

outside snail for ~48 hrs 2nd larval stage

completed and parasite can directly penetrate skin of human host

Parasite mates in host Eggs are passed out

through urine or fecal matter

Where is it found?

Common Symptoms Symptoms are caused by the body’s reaction to the

eggs. Can cause inflammation and scarring of bladder or

intestines Within days of infection host may develop a rash or

itchy skin. Within 1-2 months of infection, symptoms may

develop including fever, chills, cough, and muscle aches.

Symptoms

Chronic schistosomiasis Without treatment, schistosomiasis can

persist for years. Signs and symptoms of chronic schistosomiasis include:

abdominal painenlarged liverblood in the stool or blood in the urineproblems passing urine.

Chronic infection can also lead to increased risk of bladder cancer.

Rarely, eggs are found in the brain or spinal cord and can cause seizures, paralysis, or spinal cord inflammation.

Symptoms

No vaccine available Drink and bathe in fresh water that is not

contaminated Minimize intermediate host population

Difficult b/c harmful to other fresh water organisms Certain species of blood flukes can also infect cattle

Runoff into freshwater source can lead to further contamination

Prevention

Anti-parasitic medication Anti-inflammatory medication

Eradication efforts

Treatment