1. Liver& lung trematodes Mrs. Dalia Kamal Eldien MSc in Microbiology Mrs. Dalia Kamal Eldien MSc in Microbiology Lecture NO-18-

2. Objectives  Review of classification of Trematodes  Common species of Liver flukes  Fasciola hepatica (Clinical features, infective stage, life cycle& diagnosis)  Clonorchis sinensis (Clinical features, infective stage, life cycle& diagnosis)  Lung flukes, Paragonimus westermani (Clinical features, infective stage, life cycle& diagnosis)

3. Phylum : Platyhelminthes Class : Trematoda  Intestinal trematode  Fasciolopsis buski  Heterophyes heterophyes  Metagonimus yokogawai  Liver trematode  Fasciola hepatica  Fasciola gigantic  Clonorchis sinensis  Lung trematode  Paragonimus westermani  Blood trematode  Schistosomahaematobium  Schistosoma mansoni  Shsistosoma japonicum

4. Fascioliasis  Fascioliasis is a parasitic infection typically caused by Fasciola hepatica, which is also known as " common liver fluke" or "sheep liver fluke"  A related parasite, Fasciola gigantica, or "cattle liver fluke" also can infect people.  Human fascioliasis occurs worldwide in temperate regions.  This fluke primarily causes zoonotic disease in sheep and other domestic animals.  Humans are infected by eating aquatic plants contaminated by the metacercariae.

5. Fasciola hepaticais a large liver fluke, leaf like with an anterior conical projection

6. Life cycle of liver flukes in animal  Liver flukes mature and live in the bile ducts of the host where they lay large numbers of eggs.  The eggs are then passed down the bile ducts and enter the intestine to eventually be excreted with the faeces.  With favorable circumstances – water and moist conditions – the eggs hatch into larvae (miracidia) which invade the intermediate host (snail). To survive they should reach the host snail within 24 to 30hours as they have a short life span.  After five to eight weeks and several larval stages later, depending on the temperature, minute tadpole-like larvae emerge from the snail.

7.  These larvae form cysts on herbage and are eaten by cattle and sheep.  The larvae then migrate to the animal’s liver before entering the bile ducts.  Occasionally a fluke may migrate through other organs or may infect the unborn fetus.  The liver is damaged during this migration.  This damage alone may kill the animal (usually called acute fascioliasis) or may make it susceptible to black disease, a form of hepatitis

8. – Acute manifestations Fascioliasis is mostly subclinical. Acute manifestations are due to migration of larva through liver. The early symptoms of acute infection include: Malaise, intermittent fever, night sweats, and pain in the right costal area – Chronic manifestations (after the parasite settles in the bile ducts) Chronic fascioliasis is frequently asymptomatic. In symptomatic patients, irregular fever, anemia, hepatobiliary manifestations (colicky pain, jaundice), and secondary bacterial infections are present. Clinical features

9. Diagnosis  Diagnosis: characteristic eggs in stool of chronic infections, in duodenum aspirate & in bile  The eggs of F. buski can be difficult to distinguish from Fasciola hepatica.

10. Fasciola hepatica egg

11. Fasciolopsis buski (left) and Fasciola hepatica (right)

12. Clonorchis sinensis  Conorchis sinensis is a widespread parasite found in Southeast Asia that infects the biliary passage in humans.  The fluke is oblong, flat, transparent, and relatively small (10-25 mm long by 3-5 mm wide).  It has a pointed anterior and rounded posterior end.

13.  Humans are infected by eating raw or partially cooked freshwater fish or dried salted fish infected with the metacercariae.  In the duodenum, the cyst is digested and an immature larva released.  The larva enters the biliary duct, where it develops and matures into an adult worm.  The adult worm feeds on the mucosal secretions and begins to lay fully embryonated operculated eggs, which are excreted in the feces.  Upon reaching fresh water and upon ingestion by a suitable species of operculate snails (first intermediate host), the eggs hatch to produce a miracidium. Life cycle

14.  Inside the snail, the miracidia multiply asexually through a single generation of sporocysts and 2 generations of rediae to fork-tailed cercariae.  The cercariae escape from the snail to the water and penetrate under scales of freshwater fish (second intermediate host).  In the fish, the cercariae lose their tails and encyst in the scale or muscle of the fish to the metacercariae, which are infectious to humans.

15.  Symptoms: Clonorchiasis is frequently asymptomatic, symptoms of high fever, eosinophilia, and rash occurs in individuals with acute infection. Patients with chronic clonorchiasis may have tender hepatomegaly, progressive ascites, and jaundice.  In chronic stage clonorchiasis may be complicated by recurrent pyogenic cholangitis and jaundice associated with cholangiocarcinoma.

16. Diagnosis  Diagnosis: Diagnosis is based on symptoms and presence of endemic infection in the area.  Definitive diagnosis is dependent on finding the characteristic eggs in the feces or biliary drainage.

17. Eggs: 30-35 by 12-20 µm, are operculated at one end and have a small knob on the other end. The color is yellow

18. Adults is 10-25 mm by 3-5 mm

19. Lung flukes  Human lung fluke infection, most commonly with Paragonimus westermani, is most common in China, Korea, Thailand and Philippines.  Humans are infected by eating raw or partially cooked crab or crayfish.  Reservoirs are dogs & cats  Adult worm lives in lung, inhabits parenchyma of the lung close to bronchioles, are very small 10 x 5 mm  Paragonimus westermani is a thick, fleshy, reddish brown, egg-shaped (7.5 x4.5 mm).

20. Life cycle  The infection is typically transmitted via ingestion of metacercariae contained in raw freshwater crabs or crayfish.  In the duodenum, the cyst wall is dissolved, and metacercariae are released.  The metacercariae migrate by penetrating through the intestinal wall, peritoneal cavity, and, finally, through the abdominal wall and diaphragm into the lungs.  There, the immature worms finally settle close to the bronchi, grow, and develop to become mature worms.

21.  Adult worms begin to lay the eggs, which are unembryonated and are passed out in the sputum, however if they are swallowed, they are excreted in the feces.  The eggs develop further in the water.  In each egg, aciliated miracidium develops during a period of 2-3 weeks.  The miracidium escapes from the egg and penetrates a suitable species of snail (first intermediate host), in which it goes through a generation of sporocysts and 2 generations of rediae to form the cercariae. The cercariae come out of the snail, invade a freshwater crustacean (crayfish or crab), and encyst to form metacercariae. When ingested, these cause the infection, and the cycle is repeated.

22. Paragonimiasis – Acute manifestations: Acute pulmonary infection is characterized by low-grade fever, cough, night sweats, chest pain, and blood-stained rusty-brown sputum. – Chronic manifestations: Lung abscess or pleural effusion develops in individuals with chronic infections. Fever, hemoptysis, pleurisy pain, dyspnea, and recurrent attacks of bacterial pneumonia are the common symptoms. The condition mimics pulmonary tuberculosis. – Fever, headache, nausea, vomiting, visual disturbances, motor weakness, and localized or generalized paralysis are the symptoms of cerebral paragonimiasis.

23.  Diagnosis: Diagnosis is based on history and symptoms. Eggs are found in rust colored sputum, often being examined for tuberculosis. Or eggs in stool

24. Eggs measure 80-100 by 40-60 µm, are golden-brown with a thick shell and a prominent operculum. Eggs are recovered from sputum and faeces.

25. This is the last lecture in clinical parasitology, I wish all of you luck and success