PARAGONIMUS WESTERMANI DR JAGADEESH Class for 2013 MBBS

PARAGONIMUS WESTERMANI DR. JAGADEESH Class for 2013 MBBS 23 -06 -15

Paragonimus westermani • Major species of lung fluke to infects humans, causing paragonimiasis. • Sometimes is called the Japanese Lung fluke or Oriental Lung fluke. • Commonest in eastern Asia and in South America. • First detected by Naterer in 1828 • Kerbert detected flukes when two Bengal tigers died of paragonimiasis in zoos in Europe in 1878.

Kingdom: Animalia Phylum: Platyhelminthes Class: Trematoda Order: Plagiorchiida Family: Troglotrematidae Genus: Paragonimus Species: P. westermani Binomial name. Paragonimus westerman Subspecies. P. westermani filipinus P. westermani ichunencis P. westermani japonicus P. westermani

Epidemiology • More than 40 species but only 10 species infect human. • Endemic in many parts of world except North America and Europe. Mainly in Korea , Japan , Taiwan , China. • Other members—P , miyazaki , P. Skrjabini , P. heterotrema • India--- endemic in North East states. • HABITAT----parenchyma of lungs

MORPHOLOGY Morphology of typical Paragonimus: AC: acetabulum (ventral sucker) CE: cecum, EB: excretory bladder OS: oral sucker, OV: ovary TE: testes, UT: uterus

Morphology • Resembles a coffee bean when alive. • Adult worms are 8 mm to 16 mm long and 4 mm to 6 mm wide thick fleshy , oval. • The thickness ranges from 3. 5 mm to 5 mm. • The skin of the worm (tegument) is thickly covered with scale like spines. • The oral and ventral suckers are similar in size, with the latter placed slightly pre-equatorially.

Morphology • The excretory bladder extends from the posterior end to the pharynx. • The lobed testes are adjacent from each other located at the posterior end, and the lobed ovaries are off-centered near the center of the worm (slightly postacetabular).

Morphology • The uterus is located in a tight coil to the right of the acetabulum, which is connected, to the vas deferens. • The vitelline glands, which produce the yolk for the eggs, are widespread in the lateral field from the pharynx to the posterior end. Inspection of the tegumental spines and shape of the metacercariae may distinguish between the 30 -odd species of Paragonimus spp. but the distinction is sufficiently difficult to justify suspicion that many of the described species are synonyms.

Morphology • Eggs: • SIZE: Range from 80 to 120 µm long by 45 to 70 µm wide. • COLOUR: yellow-brown • SHAPE: Ovoid or elongate, • SHELL: Thick shell, and often asymmetrical with one end slightly flattened.

Morphology • At the large end, the operculum is clearly visible. The opposite (abopercular) end is thickened. • The eggs are unembryonated when passed in sputum or feces. • Cercaria (not shown): Cercariae are often indistinguishable between species. There is a large posterior sucker, and the exterior is spined. • Metacercaria: Metacercariae are usually encysted in tissue. The exterior is spined and has two suckers.

Paragonimus westermani egg

HOSTS DEFINITIVE HOST: • Man, Dog, Cat etc ( carnivorous animals). FIRST INTERMEDIATE HOST: Fresh water snail SECOND INTERMEDIATE HOST Crab or cray fish Metacercaria are infective form

Life cycle • Unembryonated eggs are passed in the sputum of a human or feline. • Two weeks later, miracidia develop in the egg and hatches. • The miracidia penetrate its first intermediate host (snail). Within the snail mother sporocyst form and produce many mother rediae, which subsequently produce many daughter rediae which shed crawling cercariae into fresh water.

Life cycle • The crawling cercariae penetrate fresh water crabs 2 nd intermediate hosts and encyst in its muscles becoming metacercaria. • Humans or felines then eat the infected crabs raw. Once eaten, the metacercaria excysts and penetrates the gut, diaphragm and lung where it becomes an adult worm in pairs.

Life cycle • 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.

Life cycle

Transmission • Primarily occurs through the consumption of raw or undercooked seafood. • Metacercariae may contaminate the fingers/utensils of the person preparing the meal. Accidental transfer of infective cysts can occur via food preparers who handle raw seafood and subsequently contaminate cooking utensils and other foods.

Transmission • Consumption of animals which feed on crustaceans can also transmit the parasite, for cases have been cited in Japan where raw boar meat was the source of human infection. Food preparation techniques such as pickling and salting do not exterminate the causative agent.

Pathogenesis • Metacecaria penetrate intestinal wall—migrate to abdominal cavity (abdominal tenderness nausea vomiting). ---migrate to lungs and develop into adult worm causing pulmonary paragonimiasis

Pulmonary paragonimiasis • Adult worm---initilly eosinophilic granulomatous inflammation in the lungs leading to formation of encapsulating fibrotic capsule or cyst surrounding the worm. (Rt lung) • Cysts 1 cm in size contains blood mixed thick purulent fluid containing i or more flukes and golden colour eggs—when cyst break up into bronchioles blood mixed sputum is expectorated.

• Symptoms appear with moderate to heavy infection. Features—productive cough with blood tinged rusty sputum with offensive fishy odour. • Some times frank haemoptysis with peripheral blood eosinophilia. • In chronic cases—bronchitis , bronchiectasis or pneumonia lead to lung abscess.

Extra pulmonary Paragonimiasis Worm may migrate from ruptured cyst to other parts-liver , spleen , abdominal wall , brain. (P. heterotremus). Cerebral paragonimiasis-most sever, encapsulated cyst in brain parenchyma as spece occupying lesions---fever, headache, vomiting, motor weakness or epilepsy. Cutaneous paragonimiasis---migratory subcutaneous nodules, tender may be few mm to 10 cm

Lab diagnosis • Sputum microscopy---early morning coughed sputum , saline mount for charecteristic operculated eggs. • If egg burden less--- multiple sputum examination , or formalin ether concentration technique. Mucoid sputum must be liquified • Stool microscopy—in children.

• SEROLOGY • To detect in early stages • Antibody detection---CFT (positive in active infection), IHAT, LA. • ELISA---using purified adult excretorysecretory antigen to detect parasite specific— Ig. G or Ig. E • Antigen detection---Dot ELISAA • Other tests---peripheral blood eosinophilia , CXR , MRI , CT

Treatment • Praziquantel has been used to effectively treat paragonimiasis by separating the tegument. • An effectively complete rate of cure may be expected after three days of treatment if there has not been too much permanent damage, such as from intracranial effects. • Other medications can also be used such as bithionol, niclofan, and triclabendazole with high cure rates.

Prevention • Thorough cooking of an infected crustacean kills all stages of the parasite. • Crab meat should not be eaten raw, even if pickled, because the pickling solution often fails to kill all the parasites. • Utensils and cutlery boards should be cleaned thoroughly before and after food preparation