Zoo113 Platyhelminthes PDF

Asst. Prof. Arvin Jet B. Marcaida Dept. of Biology, College of Science University of the Philippines Baguio z ZOO 113: Parasitology Platyhelminthes z Class Trematoda ▪ Digenetic trematode or flukes ▪ Most common and abundant parasitic...

Asst. Prof. Arvin Jet B. Marcaida Dept. of Biology, College of Science University of the Philippines Baguio z ZOO 113: Parasitology Platyhelminthes z Class Trematoda ▪ Digenetic trematode or flukes ▪ Most common and abundant parasitic worms, second only to nematodes ▪ All classes of vertebrates ▪ At least two hosts ▪ Cause economic losses to society z Body form ▪ Exhibit a great variety of shapes and sizes as well as variations in internal anatomy ▪ Size from 0.16 mm to 5.7 cm in length and 2.5 cm in width ▪ Dorsoventrally flattened and oval in shape, but some are as thick as they are wide ▪ Some are filiform, round, or even wider than they are long z Body form ▪ Powerful oral sucker surrounds mouth ▪ Acetabulum or ventral sucker ▪ Lappets, tentacles, spines, retractable proboscis z Body form z Development and Life cycle ▪ At least two host serve in life cycle ▪ Vertebrate (w/ a few exceptions) ▪ Mollusk ▪ Sexual and asexual reproduction (i.e., budding, polyembryony, parthenogenesis) z Life cycle ▪ EGG – brought out through sputum, feces, urine, deposited in land and ingested by snail BUT is deposited ▪ MIRACIDIUM – ciliated, swimming larva; penetrates body wall of a snail ▪ SPOPOROCYST – saclike, gutless, with several embryo /germ cells; embryo develops into another sporocyst or: ▪ REDIA – w/ mouth, pharynx, gut plus embryos; travels to gonads/ digestive tract. ▪ CERCARIA – w/ digestive tract, suckers, tail; leaves the snail host searches for 2nd IH or encyst in vegetation ▪ METACERCARIA – encysted larvae; tissues of 2nd IH; excyst and migrate to their characteristic location and mature z Digenean Systematics z Digenean Systematics z Order Echinostomatiformes Family Echinostomatidae Echinostoma spp. ▪ Echinostomes ▪ Circumoral collar of peglike spines ▪ Slender w/ large preequatorial acetabula, pretesticular ovaries, and tandem testes ▪ Vitellaria are voluminous and mainly postacetabular ▪ Parasites of intestines or bile duct of reptiles, birds, and mammals (aquatic environments) ▪ Echinostoma ▪ Cosmopolitan ▪ Non-host specific parasites ▪ At least 15 species in humans ▪ Fairly common in the Orient (Taiwan and Indonesia) ▪ Model species in Experimental Parasitology z Order Echinostomatiformes Family Echinostomatidae Echinostoma spp. z Order Echinostomatiformes Family Echinostomatidae Echinostoma spp. ▪ Pathology ▪ Echinostomiasis ▪ Physical damage to the intestinal epithelium ▪ Epigastric and abdominal pain, malaise, weight loss, anorexia, nausea, vomiting, and diarrhea ▪ Ulceration and erosion, bleeding, and chronic gastritis ▪ Adenocarcinoma z Order Echinostomatiformes Family Echinostomatidae Echinostoma spp. ▪ Diagnosis ▪ Stool analysis (Kato-Katz) ▪ PCR ▪ Endoscopy ▪ Treatment ▪ Praziquantel z Order Echinostomatiformes Family Fasciolidae Fasciola hepatica (liver fluke) z Order Echinostomatiformes Family Fasciolidae Fasciola hepatica (liver fluke) ▪ Pathology ▪ Fascioliasis ▪ Liver rot (migration of flukes through liver parenchyma) ▪ Anemia ▪ Pipestem fibrosis of the bile ducts ▪ Cirrhosis of the liver ▪ Jaundice ▪ Gallbladder damage ▪ Migrating juveniles in ectopic locations such as the eye, brain, skin, and lungs z Order Echinostomatiformes Family Fasciolidae Fasciola hepatica (liver fluke) ▪ Diagnosis ▪ Stool analysis ▪ Enzyme-linked immunosorbent assa (ELISA) ▪ Treatment ▪ Excretory/secretory antigens as potential vaccines ▪ Proteases ▪ Fatty acid binding proteins (FABP) ▪ Saposin-like lytic proteins ▪ Chemotherapy (Rafoxanide) ▪ Oxidative phosphorylation ▪ Triclabendazole  Order Strigeiformes z Family Schistosomatidae Schistosoma mansoni, S. japonicum, S. haematobium, S. intercalatum (Blood flukes)  Order Strigeiformes z Family Schistosomatidae Schistosoma mansoni, S. japonicum, S. haematobium, S. intercalatum (Blood flukes) ▪ Pathology ▪ Schistosomiasis / Bilharziasis / Snail fever ▪ 3 phases (Migratory, Acute, and Chronic) ▪ Migratory – symptomless, dermatitis (Swimmer’s itch) ▪ Acute – egg productions leads to immune response (Katayama fever) ▪ The change in antigen-antibody ratio leads to formation of large immune complexes that must be cleared by cells of the Reticuloendothelial system ▪ Chills and fever, fatigue, headache, malaise, muscle aches, lymphadenopathy, and gastrointestinal discomfort  Order Strigeiformes z Family Schistosomatidae Schistosoma mansoni, S. japonicum, S. haematobium, S. intercalatum (Blood flukes) ▪ Pathology ▪ Schistosomiasis / Bilharziasis / Snail fever ▪ Acute – egg productions leads to immune response (Katayama fever) ▪ High eosinophilia, and granulomas around eggs contain large numbers of eosinophils, as well as neutrophils and macrophages ▪ Pseudotubercles  Order Strigeiformes z Family Schistosomatidae Schistosoma mansoni, S. japonicum, S. haematobium, S. intercalatum (Blood flukes) ▪ Pathology ▪ Schistosomiasis / Bilharziasis / Snail fever ▪ Chronic – commonly asymptomatic or intestinal schistosomiasis ▪ Mild, chronic, bloody diarrhea with mild abdominal pain and lethargy ▪ Schistosomiasis haematobia, pain on urination and blood in urine  Order Strigeiformes z Family Schistosomatidae Schistosoma mansoni, S. japonicum, S. haematobium, S. intercalatum (Blood flukes) ▪ Pathology ▪ Schistosomiasis / Bilharziasis / Snail fever ▪ Chronic – commonly asymptomatic or intestinal schistosomiasis ▪ Eggs become lodged in the intestinal wall ▪ Granulomatous reaction ▪ Obstruction of the colon and blood loss ▪ Eggs become lodged in the liver ▪ High blood pressure, enlarged spleen ▪ Ascites  Order Strigeiformes z Family Schistosomatidae Schistosoma mansoni, S. japonicum, S. haematobium, S. intercalatum (Blood flukes) ▪ Pathology ▪ Schistosomiasis / Bilharziasis / Snail fever ▪ Chronic – urinary tract schistosomiasis ▪ Blood in urine ▪ Pain or difficulty urinating and frequent urination ▪ Blood loss leads to iron deficiency anemia ▪ Blocking the urinary tract and bladder cancer ▪ Genital, urinary, kidney involvement  Order Strigeiformes z Family Schistosomatidae Schistosoma mansoni, S. japonicum, S. haematobium, S. intercalatum (Blood flukes) ▪ Diagnosis ▪ Repeated stool/urine tests ▪ Serological/Blood tests (antigen) ▪ Sophisticated imaging techniques ▪ Treatment ▪ Praziquantel ▪ Oxamniquine ▪ Metrifonate ▪ Control ▪ Hygienic waste disposal ▪ Community commitment, education, healthcare facilities z Order Opisthorciformes Family Opisthorchiidae Clonorchis sinensis (Chinese liver flukes) z Order Opisthorciformes Family Opisthorchiidae Clonorchis sinensis (Chinese liver flukes) ▪ Pathology ▪ Clonorchiasis ▪ Second-order bile – erosion of epithelium lining, excess mucus production, and epithelial cell proliferation ▪ Heavy eosinophil and mononuclear infiltration ▪ Periductal fibrosis, and necrosis and atrophy of surrounding liver cells z Order Opisthorciformes Family Opisthorchiidae Clonorchis sinensis (Chinese liver flukes) ▪ Diagnosis ▪ Stool analysis ▪ Liver test ▪ Treatment ▪ Praziquantel z Order Opisthorciformes Family Opisthorchiidae Opisthorchis spp. z Order Plagiorchiformes Family Dicrocoeliidae Dicrocoelium dendriticum z Order Plagiorchiformes Family Dicrocoeliidae Dicrocoelium dendriticum ▪ Pathology ▪ Dicrocoeliasis ▪ Same as those for fascioliasis ▪ Except that there is no trauma to the gut wall or liver parenchyma resulting from migrating juveniles ▪ General biliary dysfunction, with several symptoms, such as bile duct inflammation and fibrosis and hepatocyte degeneration, is typical z Order Plagiorchiformes Family Dicrocoeliidae Dicrocoelium dendriticum ▪ Diagnosis ▪ Stool analysis ▪ Treatment ▪ Benzimidazoles ▪ Praziquantel z Order Plagiorchiformes Family Troglotrematidae Paragonimus spp. z Order Plagiorchiformes Family Troglotrematidae Paragonimus spp. ▪ Pathology ▪ Paragonimiasis ▪ Few or no symptomatic pathological conditions ▪ Lung or an ectopic site – it stimulates an inflammatory response. ▪ Spinal cord – paralysis ▪ Heart – fatal cases ▪ Cerebral – cerebral cysiticercosis ▪ Pulmonary – chest symptoms, breathing difficulties, chronic cough, sputum containing blood or brownish streaks (eggs). Rare cases. z Order Plagiorchiformes Family Troglotrematidae Paragonimus spp. ▪ Diagnosis ▪ Sputum, aspirated pleural fluid, feces, ulcer ▪ X-ray examination ▪ Seroimmunological diagnosis ▪ Intradermal test ▪ Assay test ▪ Treatment ▪ Praziquantel z Class Monogenea ▪ 8000 parasitic species (25,000 are thought to exist) ▪ Hermaphroditic ectoparasites ▪ Vertebrates, particularly fish (gills, external surfaces, ureters), turtles, frogs, salamanders, and caecilians (bladders) ▪ Invertebrates (crustaceans and squid) ▪ Causes fish deaths (hatcheries or farming operations) z Body form ▪ Bilaterally symmetrical, but with partial asymmetry ▪ Haptor (formerly known as opisthaptor) ▪ Cephalic region (anterior to pharynx) ▪ Trunk (Body proper) ▪ Peduncle (portion of body tapered posteriorly) ▪ Small (0.003 mm to 20.00 mm) ▪ Dorsal surface usually convex ▪ Colorless or gray z Development and Life cycle ▪ Single-host life cycle ▪ Egg ▪ Oncomiracidium ▪ Resembles a ciliate protozoan in shape and size ▪ 3 zones of cilia ▪ Cephalic glands, 1 or 2 pairs of eyes, digestive tract, excretory pores, hook sclerites ▪ Adult z Class Cestoda ▪ Tapeworms ▪ Intestines or its diverticula (rarely in coelom) of vertebrates ▪ Wild animals, domestic animals, and humans z Body form ▪ Strobila ▪ Linear series of sets of reproductive organs of both sexes ▪ Genitalium ▪ Proglottid or proglottis (monozoic / polyzoic) ▪ Strobilation ▪ Gravid z Body form ▪ Strobila ▪ Linear series of sets of reproductive organs of both sexes ▪ Apolysis (pseudoapolysis / anapolysis / hyperapolysis) ▪ Craspedote / Acraspedote z Body form ▪ Scolex (plu: Scolices) ▪ Head that may be equipped with a variety of holdfast organs ▪ Suckers, grooves, hooks, spines, glands, tentacles, or combinations of these ▪ Simple or absent ▪ Pseudoscolex ▪ Acetabula, bothria, and bothridia z Body form ▪ Scolex (plu: Scolices) ▪ Head that may be equipped with a variety of holdfast organs ▪ Rostellum ▪ Apical organ or anterior canal ▪ Neck z Body form z Development and Life Cycle z Order Diphyllobothriidea Family Diphyllobothriidae Diphyllobothrium spp. z Order Diphyllobothriidea Family Diphyllobothriidae Diphyllobothrium spp. ▪ Pathology ▪ Diphyllobotriasis ▪ Asymptomatic or have poorly defined symptoms ▪ Vague abdominal discomfort, diarrhea, nausea, and weakness ▪ Megaloblastic anemia (Vitamin B12) ▪ Pernicious anemia z Order Diphyllobothriidea Family Diphyllobothriidae Diphyllobothrium spp. ▪ Diagnosis ▪ Stool analysis ▪ Treatment ▪ Niclosamide (Yomesan) ▪ Praziquantel z Order Cyclophyllidea Family Taeniidae Taenia saginata / T. asiatica / T. solium z Order Cyclophyllidea Family Taeniidae Taenia saginata / T. asiatica / T. solium ▪ Pathology ▪ Taeniasis ▪ Similar to those of infection by any large tapeworm ▪ Avitaminosis B12 is unknown ▪ Asymptomatic or have mild to moderate symptoms ▪ Dizziness, abdominal pain, diarrhea, headache, localized sensitivity to touch, and nausea ▪ Delirium is rare ▪ Intestinal obstructions, hunger pains, loss of appetite, allergic reactions z Order Diphyllobothriidea Family Diphyllobothriidae Diphyllobothrium spp. ▪ Diagnosis ▪ Stool analysis (but impossible for identification) ▪ Scolex or gravid segment ▪ ELISA and PCR ▪ Treatment ▪ Niclosamide (Yomesan) ▪ Praziquantel  Order Cyclophyllidea z Family Hymenolepididae Hymenolepis nana / H. diminuta (dwarf tapeworm)  Order Cyclophyllidea z Family Hymenolepididae Hymenolepis nana / H. diminuta (dwarf tapeworm) ▪ Pathology ▪ Hymenolepiasis ▪ Rare and usually occur in massive infections ▪ Autoinfection ▪ Same symptoms with Taenia saginata  Order Cyclophyllidea z Family Hymenolepididae Hymenolepis nana / H. diminuta (dwarf tapeworm) ▪ Diagnosis ▪ Stool analysis (but impossible for identification) ▪ Scolex or gravid segment ▪ ELISA and PCR ▪ Treatment ▪ Niclosamide (Yomesan) ▪ Praziquantel