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Paragonimus westermani

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Presentation on theme: "Paragonimus westermani"— Presentation transcript:

1 Paragonimus westermani

2 Paragonimu westermani
AKA lung Fluke Paragonimus is a trematode 40 different species Hermaphroditic (testes and ovaries) Estimated 293 million at risk Discovered after 2 bengal tigers died in zoos in Europe in 1878. Quickly found in lungs, brain, and viscera of humans in Japan, Korea, and Phillipines

3 Geographic 22 million people in Africa, Asia, and South and Central America. Southeast Asia Particularly is affected because raw seafood is popular there. Humans get infected with this disease by eating raw crabs, fish that are carrying parasite. In Asia about 80% of freshwater crabs are infected with lung fluke.

4 Hosts Definitive: Intermediate: Reservoir-
Mammals, (Humans)- anything eat crustaceans. Intermediate: 1st- Snail 2nd- Crustaceans Reservoir- Carnivores, pigs, some rodents, pigs, feline species.

5 Morphology Adult worms are 7.5 mm to 12 mm long.
4mm to 6mm at greatest width. Very thick measuring 3.5mm to 5.0 mm In life appearance they are reddish brown, “coffee beans”

6 Pathogenesis Invasive stages cause few or no pathological conditions.
Once in lung, worm stimulates an inflammatory response. Makes a capsule out of granulation tissue. These capsules often ulcerate and heal slowly.

7 Life Cycle The eggs are excreted unembryonated in the sputum, or alternately they are swallowed and passed with stool .  In the external environment, the eggs become embryonated , and miracidia hatch and seek the first intermediate host, a snail, and penetrate its soft tissues .  Miracidia go through several developmental stages inside the snail : sporocysts , rediae , with the latter giving rise to many cercariae , which emerge from the snail.  The cercariae invade the second intermediate host, a crustacean such as a crab or crayfish, where they encyst and become metacercariae.  This is the infective stage for the mammalian host .  Human infection with P. westermani occurs by eating inadequately cooked or pickled crab or crayfish that harbor metacercariae of the parasite .  The metacercariae excyst in the duodenum , penetrate through the intestinal wall into the peritoneal cavity, then through the abdominal wall and diaphragm into the lungs, where they become encapsulated and develop into adults (7.5 to 12 mm by 4 to 6 mm).  The worms can also reach other organs and tissues, such as the brain and striated muscles, respectively.  However, when this takes place completion of the life cycles is not achieved, because the eggs laid cannot exit these sites.  Time from infection to oviposition is 65 to 90 days.  Infections may persist for 20 years in humans. Animals such as pigs, dogs, and a variety of feline species can also harbor P. westermani.

8 Metaceraria Cercariae

9 Whats wrong with me?

10 Disease Symptoms Diagnosis:
Pain and severe coughing (some blood= hemoptysis). fever, chest pain, sweats, asymptomatic, abdominal pain, wheezing. Diagnosis: Is done by looking at sputum (slime from the lungs), to see if any lung fluke eggs are present, or matter from paragonimus-caused ulcer. Cerebral Spinal Fluid Test Feces can be examined too. Also X-rays and biopsies can be taken.

11 Treatment Paragonimiasis is usually treated with a drug called praziquantel. (95% efficiency) Praziquantel is an anthelmintic used in most schistosome and many cestode infestations. Salting does not kill parasite, cooking and freezing does. After ingestion, takes about 3 months for lung fluke to start laying. Host might stay infected up to 20 years.

12 Paragonimus kellicotti

13 Geography This species is an endemic (Native) to North America. Found East of the Rockies. Well known pathogen in wild/domestic animals such as cat, dog, possum, skunk, mink, etc..

14 Hosts Passes through 3 hosts total. Definitive Host- Intermediate-
Larval form pass through aquatic snail, then to a crustacean, before eaten by mammal. Definitive Host- mammals Intermediate- In North America, the first intermediate host for P. kellicotti is Pomatiopsis lapidaria, an amphibious snail that ranges from the southeastern and midwestern United States into Ontario, Canada. Second is the crayfish.

15 Treatment Serological tests- antibody detections, lung biopsy.
Sputum and fecal examinations to look for eggs in sample. Can infect humans, more prevalent for wild/domestic mammals. Can be treated with praziquantel. (71-75% cure rate) More severe infections must be surgically removed by removing larvae, but it problematic. triclabendazole – used for treatments in animals.

16 Prevention/Control Control of Paragonimus in animals (mammals) is impractical. The control of the snail and crustacean intermediate hosts is also impractical But the control in humans is possible in education on preparation of food. Always thoroughly cook your food!!!!!

17 Control Keep dogs and cats on a leash or have them indoors.
But cats and dogs do not pose a threat for humans since we do not eat cats or dogs.

18 True/ False Paragonimus kellicotti is endemic in North America?
There are only 20 species of Paragonimus? The definitive host in Paragonimus westermanii is crustaceans? Treatment is most effective with the drug Praziquantel?

19 References

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