Endoparasites – Ruminants

Endoparasites – Endoparasites – Ruminants Ruminants

Goals and Objectives• Understand the influence of parasitism on

production• Become familiar with the types of parasites

afflicting agricultural animals• Understand the public health implications of

selected parasites• Understand the basic principles of parasite

control and treatment

Parasitology - Ruminants

• Economic Losses– Poor ADG– Abortion– Decreased conception rates– Death

• Public Health– Zoonoses

Reasons For Economic LossesReasons For Economic Losses

-Producer Unaware of parasite -Producer Unaware of parasite damagedamage

• estimate annual parasite-related estimate annual parasite-related losses to the livestock industry at losses to the livestock industry at more than $100 millionmore than $100 million

- Timing & Frequency of treatments- Timing & Frequency of treatments-Choice of dewormer-Choice of dewormer-Parasites have greatest impact on -Parasites have greatest impact on

high producing animals.high producing animals.

What is ruminants Parasitism?What is ruminants Parasitism?

• It is a herd diseaseIt is a herd disease

• It is a production diseaseIt is a production disease

• It develops during grazingIt develops during grazing

• 99% of all pastures contaminated99% of all pastures contaminated

Level of Parasitism Related ToLevel of Parasitism Related To• Age of animalsAge of animals

• Pasture contamination levelPasture contamination level

• Stocking rate of animalsStocking rate of animals

• Grazing environment & WeatherGrazing environment & Weather

• Immune status of animalsImmune status of animals

Deworming strategyDeworming strategy

-Producers understand importance of-Producers understand importance ofinternal parasite control for productioninternal parasite control for productionefficiency.efficiency.-Deworming is now standard practice on beef-Deworming is now standard practice on beefand dairy farms.and dairy farms.-Must have correct product at the correct-Must have correct product at the correcttime.time.

Definition• Types of relationships between organism and

host– Commensal ‐ one benefits without harming theother– Mutualism ‐ both participants benefit– Parasitism ‐ one benefits at the expense of theother

Definition

• Endoparasite ‐ internal infection

• Ectoparasite ‐ external infestation

• Zoonotic infection ‐ transmission of an infection from animals to humans

Definition

• Life cycle ‐ from the start of one generation to the start of the next– Direct ‐ completion of life cycle requires a single host– Indirect ‐ completion of life cycle requires greater than one host

Direct Lifecycle

Indirect Lifecycle

Definition• Definitive Host ‐ where sexual reproduction of

parasite occurs• Intermediate Host ‐ required to complete a

developmental phase in the parasites life‐cycle,excluding sexual reproduction

• Pre‐patent Period ‐ time from infection of definitive host to the production of parasite offspring

Designing a Program in aDesigning a Program in aDairy/Meat OperationDairy/Meat Operation

• First determine the approximate level of First determine the approximate level of parasitic contaminationparasitic contamination

1.- High Parasite1.- High ParasiteContamination LevelContamination Level

• Cows grazing pasture during lactationCows grazing pasture during lactation• When rotational grazing is practicedWhen rotational grazing is practiced

2. Moderate Parasite2. Moderate ParasiteContamination LevelContamination Level

• Cows grazing pasture only during dry periodCows grazing pasture only during dry period• Cows with access to an exercise lot only (with Cows with access to an exercise lot only (with

some grass)some grass)

Low ParasiteLow ParasiteContamination LevelContamination Level

• Cows with access to dirt dry lotCows with access to dirt dry lot

4. Extremely Low Parasite4. Extremely Low ParasiteContamination LevelContamination Level

• Cows in total confinementCows in total confinement• Cows on a concrete dry lotCows on a concrete dry lot

Summary Strategy For LactatingSummary Strategy For LactatingCowsCows

• Parasites have been shown to decrease milk Parasites have been shown to decrease milk production in early lactationproduction in early lactation

• Identify parasite contamination levels in each Identify parasite contamination levels in each dairy operationdairy operation

• Design deworming program based on Design deworming program based on individuals or herd treatment relative to individuals or herd treatment relative to contamination levelscontamination levels

Parasite – IndicationsParasite – IndicationsPurpose of the testsPurpose of the tests1.1. Direct-aids in the detection of certain protozoan Direct-aids in the detection of certain protozoan

trophozoites. trophozoites. 2.2. Flotation method-eggs in feces are mixed with flotation Flotation method-eggs in feces are mixed with flotation

solution that will cause them to float to the top.solution that will cause them to float to the top.3.3. Baerman Funnel Technique-larva migrate to the bottom. Baerman Funnel Technique-larva migrate to the bottom.

Used to detect lungworms in ruminants.Used to detect lungworms in ruminants.4.4. Centrifugation technique-will detect parasitic eggs when Centrifugation technique-will detect parasitic eggs when

other techniques do not, specially heavier eggs that will not other techniques do not, specially heavier eggs that will not float. float.

5.5. MIF (merthiolate iodine formalin) –satins and preserves MIF (merthiolate iodine formalin) –satins and preserves protozoans & larvae protozoans & larvae

Modified Wisconsin Sugar FlotationModified Wisconsin Sugar FlotationMethodMethod

TechniqueTechnique• Samples can be stored if Samples can be stored if

refrigeratedrefrigerated• Sugar solutionSugar solution– – One pound of sugar.One pound of sugar.– – Add to 12 oz(355cc) of hot Add to 12 oz(355cc) of hot

water.water.• Slides can be refrigerated Slides can be refrigerated

for reading laterfor reading later

MaterialsMaterials• Sugar solution & dispensing Sugar solution & dispensing

syringesyringe• Tea strainerTea strainer• 3/5 oz dixie cups3/5 oz dixie cups• Tongue depressorsTongue depressors• Taper bottom 15cc tubesTaper bottom 15cc tubes• Test tube rackTest tube rack• Microscope slides & 22x22 Microscope slides & 22x22

mm cover slipsmm cover slips


Add 15 - 17 cc sugarAdd 15 - 17 cc sugarsolution to samplesolution to sample


Place 3 - 5 grams ofPlace 3 - 5 grams offecal material into a 3fecal material into a 3oz paper cupoz paper cup(About a thimble full)(About a thimble full)


Stir solution & fecalStir solution & fecalsample to an evensample to an evenconsistency.consistency.


Stir solution & fecalStir solution & fecalsample to an evensample to an evenconsistency.consistency.


Use a tongue depressor,Use a tongue depressor,press as much materialpress as much materialthrough strainer asthrough strainer aspossible.possible.


1. Pour into 15cc taper1. Pour into 15cc taperbottom centrifuge tube.bottom centrifuge tube.

2. Centrifuge in swinging 2. Centrifuge in swinging arm centrifuge at 900arm centrifuge at 900rpm for 5 – 7 minutes.rpm for 5 – 7 minutes.


1. Place tube in rack and top 1. Place tube in rack and top off with sugar solution to off with sugar solution to form a meniscus.form a meniscus.

2. Place 22x22 mm2. Place 22x22 mmcover slip on tubecover slip on tubeand leave in placeand leave in placefor 2 - 4 minutes.for 2 - 4 minutes.


Lift cover slip upwardLift cover slip upward& place on slide& place on slide


Use microscope toUse microscope toscan entire cover slipscan entire cover slipfor egg countfor egg count

Definition• Types of parasites

– Nematodes (phylum nemathelminthes)‐ round worms– Cestodes (phylum platyhelminthes) ‐ flat worms– Trematodes (phylum platyhelminthes) ‐ flukes– Protozoa (phylum protozoa) ‐ single‐celled eukaryotes

Nematodes• Adult worms

– male and female– range in size from large to microscopic

• Eggs →Larvae (stage 1‐4) →Adult– Most have direct life cycles– Most transmitted as infective larvae on pasture

• GI tract and lungs as adults

GI Nematodes

• ~ 11 Genera, Many Species• Sites

– abomasum, small intestine, cecum, and largeintestine

• Most ruminants = chronic infections• Production losses and clinical disease are

proportional to severity of infection

GI Nematodes – Hot complex

• Haemonchus contortus– 1” (25 mm)– Abomasum of small ruminants– feeds on blood– Clinical signs• anemia• death

Clinical signs Haemonchus

• Calf is in poor condition with ‘bottle jaw’ due to hypoproteinemia and anemia.

• It is massive direct damage, usually late winter.

Adults in the abomasum.Barberpole worm

GI Nematodes• Ostertagia ostertagi

– 1/2” (10 mm) adult worm; abomasum– most serious impact on calves– disrupt gastric acid secretion– Clinical signs

• diarrhea• ill‐thrift• poor feed conversion

Ostertagia ostertagi

GI Nematodes• Trichostrongylus axei

– “Bankrupt worm”– Adults ~1/4” (4‐8 mm); abomasum– Clinical signs– Diarrhea– dehydration– bottle jaw– emaciation

Platyhelminthes (flatworms)

• Hermaphroditic• Intermediate host (indirect life cycle)• Flattened appearance• Tapeworms (Cestodes)• Flukes (Trematodes)

Tapeworms (cestodes)

• Adult worms few inches to 15 yards long• Segmented worms with attached head(scolex)• Ruminants = intermediate host for canids andhumans• Ruminants eat eggs passed in feces of canidsor people

Tapeworms (cestodes)• Cysts in carcass, pea‐size to grape‐size (beef

measles)• People/canids infected by eating encysted

beef• Carcass condemnation• ID, WA feedlots ‐ cattle infected with beef

tapeworm of man (Taenia saginata); 10% losses in some feedlots

Taenia saginata

Liver Flukes (Trematodes)• Fasciola hepatica (most

common); Fascioloidesmagna– Live in bile ducts as adults– Aquatic snails = intermediate host– Clinical signs

• photosensitization• reduced ADG• hepatitis; clostridial dz →death

– Condemned liver at slaughter• $millions in losses

Protozoa

• Single‐celled eukaryotes• Amoeba; Ciliates (not discussed)• Apicomplexa

– Eimeria, Cryptosporium, Toxoplasma, Neospora

• Flagellates– Tritrichomonas, Giardia

Apicomplexa• Intracellular protozoa• Coccidia

– Sexual reproduction in intestine → oocysts in feces → definitive (direct) host or intermediate (indirect) host

Eimeria• Direct life‐cycle (all ruminants)• Invade intestinal epithelium

– destruction of epithelial cells– disruption of intestinal function

• Clinical signs– acute and chronic disease– watery and/or bloody diarrhea– decreased ADG → clinical disease → death– young >> adult

Cryptosporidium parvum• Apicomplexa• Similar to Eimeria• Clinical signs

– diarrhea 1‐2 week old calves– disease severity varies

• Zoonotic: – particularly with immunocompromised host

Toxoplasma gondii• Indirect life‐cycle• Cat = definitive host

– oocysts shed in cat feces• Ruminants = intermediate

host– tissue cysts

• Transmission to developing foetus– abortion

• Zoonotic

Neospora caninum• Indirect life‐cycle• Dog = intermediate host• Clinical signs

– abortion– neurologic disease in calves born alive

Flagellates

• Mastigophora (flagellates that move with a whip)

• Extracellular parasites• One or more flagella ‐ assist with movement• Divide by binary fission• Example

– Tritrichomonas foetus

Tritrichomonas foetus• Simple reproduction

– binary fission– trophozoite is only stage

• Venereal disease of cattle (bull = carrier)

• Clinical signs– early abortion– pyometra– significant $losses due to

decreased preg. rate

References• Large animal clinical procedures for veterinary technicians,

Elizabeth A. Hanie, 2006• http://www.caes.uga.edu/publications/pubDetail.cfm?pk_ID=6

196• http://courses.cals.uidaho.edu/avs/avs471/Lectures/Lectures%

202010/Lecture%20Parasites%20notes.pdf• http://cal.vet.upenn.edu/projects/dxendopar/parasitepages/trem

atodes/Fhepatica.htm• http://cal.vet.upenn.edu/projects/dxendopar/index.html#fecal• http://www.sheepandgoat.com/HairSheepWorkshop/

parasitism.html

http://www.caes.uga.edu/publications/pubDetail.cfm?pk_ID=6196

http://www.caes.uga.edu/publications/pubDetail.cfm?pk_ID=6196

http://courses.cals.uidaho.edu/avs/avs471/Lectures/Lectures%202010/Lecture%20Parasites%20notes.pdf

http://courses.cals.uidaho.edu/avs/avs471/Lectures/Lectures%202010/Lecture%20Parasites%20notes.pdf

http://cal.vet.upenn.edu/projects/dxendopar/parasitepages/trematodes/Fhepatica.htm

http://cal.vet.upenn.edu/projects/dxendopar/parasitepages/trematodes/Fhepatica.htm

http://cal.vet.upenn.edu/projects/dxendopar/index.html#fecal

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Endoparasites – Ruminants