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Paragominus westermani By Aaron Bettenhausen and Sidney Milliron.

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Presentation on theme: "Paragominus westermani By Aaron Bettenhausen and Sidney Milliron."— Presentation transcript:

1 Paragominus westermani By Aaron Bettenhausen and Sidney Milliron

2 Kingdom:Animalia Phylum:Platyhelminthes Class:Trematoda Order:Plagiorchiida Family:Troglotrematidae Genus:Paragonimus Species:P. westermani

3  Three main foci of Paragonimus spp. Asia and Oceania West and sub-Saharan Africa South and Central America

4  First described from Bengal tigers that died in zoos in Europe in 1878. Later, it was found in humans.  Named after Dutch zookeeper who kept the Bengal Tigers

5  Definitive: Humans, cats, dogs, weasels, rodents, pigs Intermediate Snails, freshwater crayfish, crabs

6 Size, shape, and color resemble coffee bean when alive. Adult Skin is heavily covered with scalelike spines Oral and ventral suckers are about equal in size, with the ventral sucker being placed slightly preequatorially.

7 Eggs Yellow-brown, ovoid, with a long thick shell Often are asymmetrical with one end flattened

8 Cercaria Often are indistinguishable between species Large posterior sucker with spined exterior


10  1 st intermediate host Eggs hatch into Miracidium after approximately 16 days Miracidium must find a snail to survive Once in the snail the mirocidium forms a sporocyst that produces Redia Redia become Cercariae, which is passed into the water

11  2nd intermediate host  Cercariae penetrate into the tissues of crabs (usually the muscles or mucosa)  The definitive host is infected when they eat the undercooked crab

12  Worms form cysts in the duodenum  Upon leaving the cyst the metacercariae leave the intestines and penetrates the diaphragm and pleura  Once in the lungs they encapsulate and become adults  Worms mate in the pleural spaces  Mated pairs form cysts which can hatch in the lungs  However most eggs are coughed up and swallowed by the host.  They leave the host by the feces

13  Causes American paragonimiasis in feline and canine species  Life cycle is essentially the same as P. westermani  Eggs are passed in the feces  Animals become infected after eating infected crayfish  Worms form cysts in the lungs  Animals can tolerate low numbers of cysts  With large numbers of cysts animals can show respiratory signs, including coughing, dyspnea, bronchiectasis, and hemoptysis  Pulmonary cysts can be seen on lung radiographs  A transtracheal wash is used to find cysts  Treated with either Praziquantel or Albendazole

14  Few symptoms in the early stages of the infection  Causes local inflammation which causes the formation of granulation tissue around the cyst.  Eggs form pseudotubercles in the lungs  Juvenile worms can migrate to the heart, brain and spinal fluid.  Cerebral cases are similar to cysticercosis  Worms in the spinal fluid can cause paralysis  Pulmonary cases characterized by chronic cough and blood in the sputum

15  Dry cough  Bloody or rust colored sputum  Chest pain  Possibly paralysis (if it migrates to spinal chord)  Epileptic symptoms (if it migrates to brain)

16  Examination of sputum, aspirated pleural fluid, or feces for eggs (eggs not present till 2-3 months post infection)  Seroimmunological diagnosis is helpful if infection is ectopic  Need to differentiate from tuberculosis

17  Praziquantel  Untreated individuals can have infection for up to 20 years, but clinical symptoms diminish after 5-6 years  Adequate cooking of crustaceans


19  Center For Disease Control: Paragonimus westermani  Gerald D. Schmidt and Larry S. Robert’s Foundations of Parasitology by Larry S. Roberts and John Janovy, Jr.,8 th edition  Metropolitan State College of Denver Department of Medical Technology

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