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Paragonimus westermani
- 1. Paragonimus westermani Gopiram (Shulav)Syangtan M.Sc. Medical Microbiology Institute of Science & Technology(IOST) TRIBHUVAN UNIVERSITY E-Mail:[email protected]
- 2. Paragonimiasis • Paragonimiasis isa food-borne parasitic infection • Paragonimiasis, or lung fluke disease, is caused by infection with a number of species of trematodes belonging to the genus Paragonimus. • The most common are: P. westermani, P. heterotremus and P. philippinensis in Asia (China, the Democratic People’s Republic of Korea, the Republic of Korea, the Lao People’s Democratic Republic, the Philippines, Thailand, Viet Nam and other east Asian countries); P. africanus and P. uterobilateralis in western and central Africa; P. caliensis, P. kellicotti and P. mexicanus in north, central and south America 2/6/2019 2G.R.(Shulav)
- 3. History • Most discoveriesmade between 1874-1918 • Discovered in Brazil in 1850 by Diesing • First described in Bengal tigers housed in zoos in Hamburg and Amsterdam in 1877 • Coenraad Kerbert named the parasite after the manager of the zoo G.F Westerman • Sidney Ringer discovered the parasite in a human in a Portuguese man during an autopsy in 1879 • Rudolf Luekart found that the parasite found in the tiger is the same as the parasite that caused hemoptysis in Formosa and Japan • 1916-1922 Japanese workers discovered the life cycle in the snail 2/6/2019 G.R.(Shulav) 3
- 4. Paragonimus spp • Alsoknown as the Oriental lung fluke ( the lung distome) pinkish-brown colour and bean shaped tremadotes. • More than 30 species of trematodes (flukes) of the genus Paragonimus have been reported to infect animals and humans. Among them, more than 10 species are reported to infect humans, the most common is P. westermani. • The parasite is endemic in the Far East—Japan, Korea, Taiwan, China, and South East Asia—Sri Lanka and India. Cases have been reported from Assam, Bengal, Tamil Nadu and Kerala. • P. mexicanus is an important human pathogen in Central and South America. 2/6/2019 4G.R.(Shulav)
- 5. Geographical Distribution Source:- WHO2015 ‘a’ 2/6/2019 5G.R.(Shulav)
- 6. Epidemiology • It isestimated that 20 million are infected with Paragonimus westermani • It is endemic in China, Korea, Japan, the Philippines, and Taiwan • Japan, Korea, Formosa, China, Manchuria, the Philippine Islands and India • Infection is also found in parts of tropical West Africa, from the Congo and Nigeria, especially from Southern Cameron • Rare in the US but it is found in Missouri 2/6/2019 G.R.(Shulav) 6
- 7. • Habitat:- adultworm live in respiratory tract (lung) of man. • Definitive Hosts:- Man and Domestic animals (usually host in Asia are the tiger & leopard) • Intermediate Host:- First Host:- A fresh-water snail of the genus Melania Second Host:- A fresh-water crayfish or a crab 2/6/2019 7G.R.(Shulav)
- 8. Morphology Fig:- Morphology ofP. westermani Adult •The adult worm is hen egg-shaped •Size:- 10 mm long, 5 mm broad and 4 mm thick. •Adults worms live in the lungs, usually in pairs in cystic spaces that communicate with bronchi. •Its anterior end is slightly broader than the posterior end. •The ventral sucker in situated near about the middle of the body. •Life span of the adult worm is about 6 to 7 years •The excretory vesicle is large and extends from the posterior extremity to the anterior region, dividing the body into two equal halves:- unbranch intestinal caeca and Caudal region. 2/6/2019 8G.R.(Shulav)
- 9. Morphology Egg •Golden brown incolour • oval in shape •flatened opercula •80-120 μm by 50-60μm in size •Contain an un-segmented ovum surrounded by yolk cell 2/6/2019 9G.R.(Shulav)
- 10. Life cycle ofP. westermani 2/6/2019 10G.R.(Shulav)
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- 12. Life cycle ofP. westermani • 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.2/6/2019 12G.R.(Shulav)
- 13. Pathogenesis • Mode ofInfections:- Eating raw, undercooked or pickled crustaceans such as crab or crayfish • Spitting, a habit in asian countries • Cultures that eat raw crustaceans • Drunken Crab in China • Raw Crab or Crayfish and alcohol in The Philippines • Gye Muchim in Korea • Sushi crab, ama ebi and odori in Japan • Infecting Agent :- Metacercaria or adolescaria in side a cyst • Portal of Entry:- Digestive tract/mouth • Site of localization:- lungs 2/6/2019 13G.R.(Shulav)
- 14. Pathology • When humansingest raw infected crustaceans, larval flukes develop in the small intestine, penetrate the intestinal wall into the peritoneal cavity 30 minutes to 48 hours after excysting. They then migrate into the abdominal wall or liver, where they undergo further development. Approximately 1 week later, adult flukes reenter from the abdominal cavity and penetrate the diaphragm to reach the pleural space and lungs. Flukes mature, a fibrous cyst wall develops around them, and then egg deposition starts 5-6 weeks after infection. • The symptoms of the early stages of this disease appear to be few with some people being 2/6/2019 14G.R.(Shulav)
- 15. pathology • The wormsfinally get into the lung parenchyma and induce acute exudative pneumonitis and haemorrhage. • They gradually mature and are encysted, thereby producing zones of active inflammation with exudate and of collagenous fibrous tissue. The worms are found usually in pairs. • When grown up, these worms are often found inside the bronchial lumen lined with bronchial epithelia of squamous metaplastic character. The cysts consist of the parasite and of dense collagenous connective tissue including various inflammatory cells and eosinophils. 2/6/2019 G.R.(Shulav) 15
- 16. Pathology • Once theparasite is in the lung or another organ, the worm stimulates an inflammatory response that eventually coats tissue. • If worms enter the CSF of the spinal cord, it can result in partial or total paralysis. • There have also been fatal cases of Paragonimiasis by infection of the heart. • Cerebral cases result in cerebral cysticercosis (condition in which fluid-filled cysts surrounding the worm are present). • The adult worm , as it move around , cause lesions (worm cyst and burrows) by mechanical damage. • The eggs excites a foreign body granulomatous reaction which may soften to form cavities, the wall of which is compose of fibrous granuloma tissue (epitheloid cell, lymphocyte,plasma cell, eosinophils, gaints cell and fibroblast.) 2/6/2019 G.R.(Shulav) 16
- 17. Clinical Manifestation 1. Pulmonaryparagonimiasis Chronic cough, Haemoptysis, pulmonary tuberculosis (stimulating a case of bronchiectasis), chest pain with dyspnoea and fever; pleural effusion and pneumothorax are possible complications. 2. Extrapulmonary paragonimiasis most frequent locations include the diarrhoea, abdominal cavity and subcutaneous tissues and, most frequently, the brain: cerebral paragonimiasis is a severe condition that may be associated with headache, visual impairment and epileptic seizures. 2/6/2019 17G.R.(Shulav)
- 18. LABORATORY DIAGNOSIS Sample specimen:-sputum, stool, gastric, aspired pleural fluid washing or Tissue material Diagnosis Technique 1. Parasitological Technique 2. Immunological Technique 3. Molecular Technique 4. Imaging Technology 2/6/2019 18G.R.(Shulav)
- 19. Parasitological Technique • MicroscopicExaminations 1. Sputum examination: (1) Alkali digestive method (10%NaOH) (2) Direct sputum smear 2. Stool examination: (1) Alkali digestion (2) Water sedimentation method (3) Direct fecal smear 3. Biopsy Materials by Staining:- Gimsa stains 2/6/2019 19G.R.(Shulav)
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- 22. Immunological Test • Non-specificTest:- 1. Intradermal skin test 2. complement fixation test • Specific Test 1. IHA 2. ELISA 2/6/2019 G.R.(Shulav) 22
- 23. Molecular Technique • PCRtechnique Conventional PCR Real Time PCR DNA Hybridization 2/6/2019 G.R.(Shulav) 23
- 24. Imaging Technology 1. ChestX-Ray :- nodular,cystic and infiltrative in the middle and lower lungs similar to TB, Bronchiectasis 2. CT-scan of Chest:- pulmonary lesions 2/6/2019 G.R.(Shulav) 24
- 25. Treatment • Praziquantel-Oral, 1. causessevere spasms and paralysis of the worms' muscles 2. Not for pregnant women Stomach pains, dizziness, fever, nausea, vomiting, headache 3. Better tolerated than Bithionel • Bithionol Diarrhea, use is limited due to side effects • Triclabendazole Can cure cases other drugs failed 2/6/2019 G.R.(Shulav) 25
- 26. CONTROL & PREVENTION •Fully cook shellfish • Heat water to 55o C for 5 minutes • Freeze Fish • -20 C for 7 days • -35 C for 15 hours • Make spitting illegal • Use Moluskicide to control snail population • Maintain the hygiene and sanitation 2/6/2019 G.R.(Shulav) 26
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