PARASI ARASITE TE TAXONOMY AXONOMY
PARASITIC WORMS • Phylum-Platyhelminthes (“flatworms”, “flukes” and “tapeworms”) • Phylum-Nemathelminthes (“roundworms”) • Phylum-Acanthocephala (“thorny-headed worms”) • Phylum-Annelida (“segmented worms”, “night crawlers”) • Phylum-Arthropoda (“tongue worms”)
Fasciola spp.
1. F. hepatica 2. F. gigantica
Scientific Classification Kingdom: Animalia Phylum: Platyhelminthes Class: Trematoda Subclass: Digenea Order Echinostomida Family: Fasciolidea Genus: Fasciola Species:hepatica & gigantica
General Information - Commonly known as liver fluke - A parasitic flatworm
Geographical Distribution - Found in Rural areas of temperate and tropical regions - Especially located in regions with cattle and sheep herding - Found on every continent with nearly 180 million people at risk and an estimated 2.4 million people already infected worldwide.
Transmission - Occurs through the ingestion of raw, fresh water vegetation - Plants become exposed to the metacercariae when the body of water that the vegetation is growing in becomes contaminated by eggs in the fecal mater of the infested host - A form of infection known as halzoun (in the Middle East) is contracted by eating the raw liver of an infected animal
Morphology - Adult has a flat leaflike body - About 20-30 mm long by 815 mm wide - Has an anterior elongation where oral and ventral suckers are located - Intestines are very branched
Hosts - Cattle - Sheep - Goats - Sometimes humans
Life Cycle
Life Cycle (Cont’d) - The adult F. hepatica lives in bile ducts of the host’s liver
- Begin to produce eggs 2-4 months after initial infection - Eggs pass down the bile duct through gastrointestinal tract and are released in the hosts feces - Require water of temperature above 10 C to hatch - The egg hatches and releases miracidiae within two weeks - These newly hatched miracidiae must find a Lymanae snail host within 24 of hatching or they will die
Life Cycle (Cont’d) - Inside the Lymanaea miracidium loses its cilia and develops into a sporocyst - Each sporocyst develops into a redia which then burst the sporocyst and migrate to the hepatopancreas of the snail - Redia then develop into cercariae - Cercariae attach to plant matter and encyst, forming metacercariae which is the infective form of the fluke - Mammalian host consumes the vegetation with the metacercariae which then excyst in the small intestine
Life Cycle (Cont’d) - Metacercariae burrow through the intestinal wall, move through the peritoneal cavity and enter the liver parenchyma - Immature flukes migrate through the liver patanchyma for 6-8 weeks giving rise to acute symptoms - Once mature they settle in the bile ducts and begin to produce their own eggs after about a month.
http://www.cdfound.to.it/hTML/fh2a.htm
Four Symptomatic Patterns - Acute Phase - Cronic Phase - Halzoun - Ectopic Infection
Acute Phase - Rarely seen in humans - Fever, tender hepatomegaly, and abdominal pain are frequent symptoms. - Vomiting, diarrhea, and anemia may also be present
Chronic Phase - More common in human population - Symptoms include: bilary cholic, abdominal pain, tender hepatomegaly, and jaundice - In children: severe anemia is common - Inflammation of the bile ducts eventually leads to fibrosis and a condition called “pipestem liver” - Severe infections can lead to death
Halzoun & Ectopic Infection - Occurs when an individual consumes infected raw liver - The adult worms can cause considerable pain, edema, and bleeding that can interfere with respiration - Adults can live in biliary ducts and cause symptoms for up to 10 years.
- In frequent, but can occur in peritoneal cavity, intestinal wall, lungs, subcutaneous tissue, and very rarely in other locations.
Diagnostic Tests - Most widely used form of diagnosis is the directly observed presence of F. hepatica eggs either in a stool sample, duodenal aspirate or biliary aspirate - Flukes do not begin to produce eggs until about 4 months after infection, so you cannot test the stool - Prior to 4 months: serological tests can be used - FAST-ELISA (most popular)
- Ultrasound can be used to visualize adult flukes in the bile ducts - CT scan can reveal burrow tracts made by the worms
Treatment - Many countries use a 5-10 day course of oral bithionol at 30mg/kg body weight - Triclabendazole is a preferred antihelmintic agent, but is unavailable in most countries. - The resistance is rising to this drug
- Along with pharmaceutical therapy, surgery may be necessary in very extreme cases to clear the biliary tract
Control Methods - Education - Molluscicides: application of malluscicides to decrease the population of Lymnaea snails - Chemotherapy
Review Questions -
1. What is the average size of an adult F. hepatica? a.
20 mm x 5mm
b.
30 mm x 13 mm
c.
10 mm x 5 mm
2. What continent can F. Hepatica be found? a.
Africa
b.
Asia
c.
America
d.
All of the above
Review (Cont’d) - 3. What is the most effective way to treat fascioliasis? a. bithionol b. flagyl c. triclabendazole
References • Sarah Richards and Max Karpyak - “Fascioliasis” Retrieved: 2/19/2007 by Richards and Karpyak http://www.stanford.edu/class/humbio103/fascioli asis/Fasciola.htm - “Fasciola hepatica.” Wikipedia, free encyclopedia. Retrieved: 2/19/2007 http://en.wikipedia.org/wiki/Fasciola_hepatica - “Fasciola hepatica.” Retrieved: 2/19/2007 http://www.cdfound.to.it/html/fas1.htm
Trichostrongylus spp. • Morphology:
Zoonoses spp. • T. axei • T. orientalis • T. probolorus • T. skirjabini • T. colubriformis • ………………
Definitive host
Trichostrongylus colubriformis third-stage larva obtained after culture of faeces
Life cycle
Prepatent period: 2-3 weeks
Trich. spicules
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Moniezia spp.
Introduction
：
Monieziosis is a cestodiasis caused by Moniezia sp. including Moniezia expansa and M.benedni
They are found in the small intestine of ruminants, like cattle,sheep,and camel, especially in lamb and calf. M.expansa :The more common in sheep and goat than in cattle M.benedni: The more common in cattle than in sheep and goat
Morphology Moniezia spp. have unarmed scolices with four large sucker sucker and very wide segments with bilateral genitalia. genitalia.
scolices
M expansa
Difference Differe nce of M. M . expansa and M. benedeni Interproglottidal Interproglottidal glands at the t he posterior margin of each segment extend the full width of M. expansa but occupy only the midzone of the M. benedeni segment.
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Characteristic of eggs The egg of Moniezia spp. found in cattle feces is one of the few eggs that appears square, and internally the pear-shaped (pyriform apparatus) characterristic of anoplocephalid eggs can be seen.
Pyriform apparatus
Life cycle of Definitive host: ruminants. Site of infection: small intestine Intermediate host: Forage mites Infective stage: cysticercoid Prepatent preiod : month 3
Moniezia
spp
Moniezia is living in small intestine of ruminant. The definitive host leaves the gravid proglottids and eggs in the feces . The oncosphere migrate into the body cavity of the mite where they develop into cysticercoids for at least 40 d and infection of the definitive host is by ingestion of infected mites during grazing. The prepatent preiod is approximately 45~60 d, but the adult worms appear to be short-lived, persist for only three months.
Epidemiology The Monieziosis distribbution is world-wide. Moniezia spp. are the commonest in young animals, and are of low pathogenicity
Their incidence shows a seasonal fluctuation, coinciding with the active period of the vectors .
Symptoms When there are lots of Moniezia, the intestines will become enteremphraxia even have been ruptured The toxin of parasite cause young animals being neurosis, including walking in circles spasm, non-food mastication.
clinical symptoms
：
Decreased appetite, emaciation, anaemia, listless, diarrhea, gravid proglottid in feces
Lesions
The disease can make corpse become thin , the colour of muscle turn light and make exudates in abdomen increase.
Others: enteremphraxia, contortion,hemorrhage
Diagnosis Diagnosis is based on a history of residence in an endemic area and symptoms. Fecal examination: When there is no proglottids in feces ,using the flotation method
Treatment 1.Bithionol: 50mg per kilogram of body weight for cattle, or 75mg to 100mg for sheep, P.O. 2.Niclosamide:50mg per kilogram of body weight for cattle, or 60mg to 75mg for sheep, P.O. 3.Mebendazole 10mg per kilogram of body weight for cattle, or 15mg for sheep, P.O. ：
4.Albendazole:5mg per kilogram of body weight for cattle, or 20mg for sheep, P.O. 5.Praziquantel 5mg to 10mg per kilogram of body weight for cattle, or 10mg to 15mg for sheep, P.O ：
Prevention • 1. Deworm before adult stage • 2.Harmless disposal of feces • 3.Improvement of breeding and management ploughing and reseeding to avoid pasturing in the early morning or at dust, when the peak of forage mite activities regularly testing forage mite within the pasture
PARASITES OF SWINE (PIGS)
Introductory Recaps • Parasitism occurs in varying degrees: 1. parasitiasis- here the parasite is present in or on the animal host, and is potentially pathogenic but the animal does not show any outward clinical signs of disease
Introductory Recaps cont. • Parasitism occurs in varying degrees: 1. parasitosis- here the parasite is present in or on the body of the animal and does produce obvious injury or harm to the host manifesting in clinical signs of parasitism.
Introductory Recaps cont. LINNAEAN CLASSIFICATION SCHEME: 1. Kingdom 2. Phylum 3. Class 4. Order 5. Family 6. Genus 7. Species Mnemonic: “King Philip came over for good spagheti” spagheti”
Local pigs
Internal Parasites • The large roundworm (ascarid) is the most common internal parasite of swine • Other roundworms include: stomach worms, intestinal treadworms, kidney worms, lungworms and nodular worms • Symptoms of worm infestation include: poor growth, thin rough hair coat, diarrhea and coughing
Internal parasites continued • Ascarid migration increases susceptibility to pneumonia • Ascarid migration results in white spots in the liver • Worms can be controlled by the use of anthelmintics and good sanitation
Common vs Technical Terms for Internal Parasites • Large roundworms = Ascarid • Stomach worms = Hydrostrongylus • Intestinal threadworms = Strongyloides • Kidney worms = Stephanurus • Lungworms = Metastrongylus • Nodular worms = Oesophagostomum • Whipworms = Trichuris
Internal parasites continued • Some common dewormers include: • Atgard = Dichlorvos (feed) • Banminth = Pyrantel Tartrate (feed) • Tramisol = Levamisole (feed or water) • Ivermectin = Ivomec (injectable
Endoparasites
Ascaris suum - roundworm • • •
• •
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Ascariasis PPP: 8 weeks CS: unthriftiness, failure to gain weight, rough hair coat, pendulous abdomen, chronic paroxysmal coughing and occasionally, abdominal expiratory dyspnea (“thumping”). Dx: fecal flotation, worms – intestines, milk spots - liver Tx: Ivermectin, fenbendazole, dichlorvos, doramectin, hygromycin, levamisole, Picture Credit: piperazine http://caltest.vet.upenn.edu/merial/swine/s ZOONOTIC: ingestion of eggs wine_6.htm (original image no longer available)
Trichuris suis - whipworm • PPP: 6 weeks • CS: diarrhea, unthriftiness • Dx: fecal flotation, adults - LI • Tx: Ivermectin, dichlorvos, hygromycin, levamisole, fenbendazole
Strongyloides ransomi - threadworm • PPP: 7 days • CS: severe diarrhea: 10 – 14 days with high mortality • Dx: fecal flotation • Tx: Ivermectin, dichlorvos, hygromycin, fenbendazole
Eimeria spp. - coccidia • PPP: 14 days • CS: piglets: enterocolitis • Dx: fecal flotation • Tx: piglets – sulfamethazine; sows decoquinate
Isospora suis - coccidia • PPP: 14 days • CS: piglets: 6 – 21 days, stunted, mortality • Dx: fecal flotation • Tx: piglets – sulfamethazine; sows decoquinate
Metastrongylus spp. – Lung worm • PPP: 1 month • CS: coughing, poor growth • Dx: fecal flotation; Adults - LI • Tx: Ivermectin, doramectin, fenbendazole, levamisole
Oesophagostomum dentatum – nodular worm • PPP: 40 days • CS: asymptomatic, nodules – gut: enteritis • Dx: fecal flotation; Adults – LI • Condemnation intestine • Tx: Ivermectin, doramectin, fenbendazole, levamisole, pyrantel tartrate, hygromycin, dichlorvos
Ascarops strongylina – stomach worm • PPP: 6 weeks – Dung beetle: intermediate host
• CS: nonpathogenic • Dx: fecal sedimentation; Adults – stomach • Tx: Ivermectin, doramectin, dichlorvos Ascarops strongylina, egg. Courtesy of Dr. Dietrich Barth, Merial
Stephanurus dentatus – kidney worm • PPP: 8 – 16 months • CS: loss of weight, condemnation organs – migrating larvae • Dx: eggs – urine sedimentation; adults – cysts perirenal fat and pelvis of kidney; larvae liver • Tx: Ivermectin, doramectin
Trichinella spiralis – Trichina worm •
LC: 4 days; 20 days for larvae to be infective
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Dx: necopsy
•
Tx: none, don’t feed uncooked garbage to pigs, cook all meat to recommended temperature and time
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ZOONOTIC: ingestion of raw meat
Taenia solium – Pork tapeworm • Taeniasis, cysticercosis • LC: 2 months, swine intermediate host • Dx: necopsy – cysterci; serologic test – humans/ pigs; eggs feces - humans • Tx: none, don’t feed human feces, cook all meat to recommended temperature and time • ZOONOTIC: ingestion of raw meat
Taenia solium cysticerci in the masseter muscle of an adult pig.
(Photo courtesy of Dr. A. Lee Willingham III,
Balantidium coli • Protozoa • LC: 6 – 14 days • CS: mild – severe enteritis • Dx: necopsy - LI ; fecal flotation • Tx: Tetracycline, metronidazole • ZOONOTIC
Figure 6-50 Trophozoite stage of Balantidium coli, the “ciliated protozoan” found in the large intestine of swine. The trophozoites
Treatments
External Parasites • Lice (hog louse) • Are blood suckers. Approximately ¼” long • Result in economic loss due to reduced performance • Control by use of insecticides • Insecticides available as a spray, pour-on, dust, granule or injectible
Mange • Caused by microscopic mites that burrow beneath the skin. • Causes severe itching • Will reduce swine performance • Control by the use of insecticides. • Ivermectin is the insecticide of choice
ECTOPARASITES
Sarcoptes scabiei – Mange mite • LC: 3 weeks • CS: pruritis and papules. • Dx: Skin scrapings • Tx: Ivermectin • ZOONOTIC
Haematopinus suis – Hog Louse • Pediculosis, host specific, contagious • LC: 3 weeks • CS: pruritis • Dx: check skin • Tx: Amitraz, Ivermectin • Prevention: Hygiene
References • K Holtgrew-Bohling , Large Animal Clinical Procedures for Veterinary Technicians, 2nd Edition, Mosby, 2012, ISBN: 97803223077323 • Laboratory procedures for Veterinary Technicians, 5 th edition, 2007, Hendrix C.M; Sirois M. • http://vetmed.iastate.edu/vdpam/new-vdpam-employees/foodsupply-veterinary-medicine/swine/swine-diseases • http://www.flockandherd.net.au/other/reader/sarcoptes%20pigs. html • http://www.ent.iastate.edu/imagegallery/ • http://nematode.net/NN3_frontpage.cgi?navbar_selection=specie stable&subnav_selection=Ascaris_suum
References • http://www.ecvpath.org/october-2008/ • http://cal.vet.upenn.edu/projects/dxendopar/parasitepages/hookl ungstrongyloides/s_ransomi.html • http://parasitology.cvm.ncsu.edu/quiz/swine/exam2/swinequizEA. php • http://uk.merial.com/producers/swine/woe/woe_04.asp • http://vetpda.ucdavis.edu/parasitolog/Parasite.cfm?ID=94 • http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/2 2605.htm • http://www.wormbook.org/chapters/www_genomesTrichinella/g enomesTrichinella.html • http://www.cesa.life.ku.dk/Cysticercosis.aspx
Parasites of Dogs and Cats Arthropods and Protozoa
Insects • Trichodectes canis (Biting louse) • Linognathus setosus (Sucking louse) • Ctenocephalides (Flea) • Cuterebra (Rodent Bot Fly)
Trichodectes canis (Biting louse) • Found as felicola sustratus in the cat • Cause roughened hair coat, itching and dermatitis • May act as intermediate host to Dipylidium caninum
Linognathus setosus (Sucking louse of dogs) • Causes skin irritation, itching, dermatitis, alopecia, anemia, roughened hair coat • Usually transmitted by direct contact, but all life stages may be transmitted by fomites • Are species specific
Ctenocephalides (Flea) • Infest dogs and cats • Vector for Dipylidium caninum, tularemia, plague, etc. • Die at temperatures below 20 F for 48 hours or at temperatures above 120 for several days • Over 200 species of fleas worldwide • Severe infestations can cause anemia
Cuterebra (Rodent Bot Fly) • Infests rodents, companion animals and occasionally humans • Larval stage that infests skin • Acts as an irritant • Migration may be fatal • Have a cutaneous lump with a breathing hole • Use care when extracting as crushing larva may result in anaphylaxis
Arachnids • Sarcoptes scabiei (Scabies) • Demodex canis (Demodectic mange) • Otodectes cynotis (Ear mites) • Cheyletiella (Walking dander mite) • Rhipicephalus sanguineus (Brown dog tick) • Dermacentor variabilis (American Dog tick) • Amblyomma americanum (Lone Star tick)
Sarcoptes Scabiei (Scabies) • Found as Notoedres cati in cats • Causes intense itching, dry and thickened skin. • Is contagious to humans and other pets • Mites burrow under the skin so may be difficult to diagnose • Diagnose through a skin scraping • Usually have “ventral blowout”
Demodex canis (Demodectic Mange) • Rare in cats • Causes areas of alopecia on head, neck, forelimbs. • Can be localized or generalized. • Diagnosed with skin scraping. • Is not contagious • Small numbers considered normal on skin flora • Genetic predisposition
Otodectes cynotis (Ear mites) • Intense pruritis of the ear canal. • Can be found on any area of the body • Feed on epidermal debris and are easily transmitted
Cheyletiella (Walking Dander mite) • Causes mild alopecia and pruritis • May cause dermatitis in humans • Ingest keratin debris and tissue fluids • Have enormous hook like accessory mouthparts • Are visible to the naked eye
Rhipicephalus sanuineus (Brown dog tick) • Vector for canine babesiosis and canine ehrlichiosis • May cause anemia or tick paralysis when found in large numbers
Dermacentor Variabilis (American Dog Tick) • Feeds on small mammals but can also feed on dogs and humans • Vector for Rocky Mountain Spotted Fever, tularemia, and can cause tick paralysis in animals and humans
Anblyomma americanum (Lone Star tick) • Gets name from white spot on apex of scutum • Feeds on animals and humans • May be vector for Rocky Mountain Spotted Fever and tularemia. • Vector of Ehrlichia
Protozoa • Neospora caninum (Neospora) • Isopora (Coccidia) • Giardia canis (Giardia) • Toxoplasma gondii (Toxo) • Sarcocystis (Sarcocystis)
Neospora caninum (Neospora) • Transmitted transplacentally or orally • May cause ascending paralysis • A type of coccidia
Isopora (Coccidia) • Diarrhea in kittens and puppies. • May be fatal • One of most commonly diagnosed protozan disorders in puppies and kittens. • Rarely a problem in mature animals • Very small in comparison to other parasites
Toxoplasma gondii (Toxo) • May cause transient diarrhea in cats • Highly pathogenic to humans, especially fetus in utero
Sarcocystis • Not very pathogenic in cats • Very pathogenic in sheep
Giardia canis (Giardia) • Causes diarrhea • Occur as cysts or trophozoites in fecal flotation. • May also be tested for through a snap test now available.
