Lung Trematodes

Lung Flukes –Chapter 18, p. 281-285Paragonimus westermani

Oriental Lung Fluke is an important human parasite in the Orient (Japan, Korea, China, SE Asia), Pacific islands (Philippines), and India. It is occasionally found in western Africa and South America.

______________________ human cases

It is occasionally found in western Africa and South America.

Parasite is not endemic in North America.

Paragonimus westermani

Recent cases have been identified in _________________________________ in Minnesota and Wisconsin.

Originally misdiagnosed as _________________________________, as the lung pathology mimics this disease.

Morphology of Adult Paragonimus westermani

Adults are 8-12 mm long x 4-6 mm wide; 3-5 mm thick.

_______________________ is lobed and located on one side of the _______________________

Egg-filled _____________________ is on opposite side of acetabulum.

Characteristic structure is the extensive _____________________ - extend from anterior end to posterior end.

________________________ are lobed and are located opposite each other in mid-posterior of body.

Morphology of Adult Paragonimus westermani

Life Cycle of Paragonimus westermani

DEFINITIVE HOSTS: Parasite shows low host specificity in that ____________________________ (primarily __________________________________) can serve as a definitive host.

- these hosts also serve as ________________________ for transmission to a human.

- thus, this parasite is a __________________________

Life Cycle of Paragonimus westermani

HABITAT: Adults live in ________________________

_____________________________________________

Life Cycle of Paragonimus westermani

1. Adults occur in pairs in the __________________________

2. __________________ are released into the bronchioles and move along the respiratory tree by ciliary action. They move into the bronchi trachea pharynx where they are:

1.

2.

Life Cycle of Paragonimus westermani

3. Eggs must be released into an aquatic habitat. _________________________ hatch and swim until they penetrate _______________________ first intermediate host.

4.Within the snail, sporocyst and redial generations occur.

Life Cycle of Paragonimus westermani

5. _______________________ _________________________ leave the snail and crawl along the pond bottom until they come in contact with a _________________________ (second intermediate host).

Life Cycle of Paragonimus westermani6. Cercariae penetrate crab or

crayfish and encyst in the muscles as _______________________

7. When crab or crayfish is eaten raw or poorly cooked, metacercariae excyst in the duodenum.

- The immature adults bore through the wall of the duodenum.

- They then ________________________ ________________________ and invade the lung bronchioles and are mature in 2-3 months.

Pathology of Paragonimus westermaniNormal bronchiole

ADULTS:

(1) bronchiolar epithelium thickens

(2) connective tissue capsules are formed around worms.

(3) these capsules often ulcerate causing hemorrhaging.

(4) fibrous connective (scar) tissue deposition occurs throughout the lungs.

Symptoms are difficulty in breathing, coughing, and bloody sputum.

• Infection often __________________________________and can be misdiagnosed

Pathology of Paragonimus westermani

IMMATURE ADULTS:

Migration of the immatures can be dangerous if the worms ________________________________and end up in ectopic sites such as the ________________________________ Fatalities may occur.

Paragonimus westermani

DIAGNOSIS - Identify eggs in the sputum or feces.

-distinct characteristic: _____________ ________________________________

- Size: 80-118 µm long and 48-60 µm wide

TREATMENT - _______________________________ is somewhat effective if lung damage is not too severe.

PREVENTION -

SPREAD DISEASE

Paragonimus kellicoti

Closely related species – identical to P. westermani

DEFINITIVE HOSTS– adults occur in wide variety of _____________________________ including ________________________________________________________________________________________________

  - distributed in North America east of the Rocky Mountains

- parasite is enzootic in Wisconsin - commonly found in ________________________

Paragonimus kellicoti

 LIFE CYCLE involves snails as first intermediate hosts and pond crayfish as second intermediate hosts.

________________________________

_____________________________ _____________________________

It is possible that humans could serve as hosts but why don’t we?

Haematoloechus medioplexus (p. 279-280)

Frog lung fluke is a common parasite of ___________________________ throughout the world. In Wisconsin? Adults are up to 8 mm long

Suckers are small

Vitellaria are grape-like

Ovary midanterior

Oblique testes

Extensive uterus covers most of the internal organs

LIFE CYCLE involves _____________________ first intermediate hosts and _____________________ second intermediate hosts.

A frog becomes infected by ingesting dragonflies containing ____________________. Why important?

Reproductive System TrematodeProsthogonimus macrorchis (p. 280)

Oviduct fluke occurs in _______________________________

ADULTS are commonly studied as a representative digenetic trematode due to its easy morphology.

Reproductive System Trematode

Prosthogonimus macrorchisAdults occur in the ________________________________________________________________________________________________________

oviduct

Prosthogonimus macrorchis

Life cycle:

Prosthogonimus macrorchis

PATHOLOGY: Parasites can damage the oviduct of the female chicken or duck and ____________________________________________

In the male host - _____________________________