Endoparasites – Ruminants. Goals and Objectives Understand the influence of parasitism on...
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Transcript of Endoparasites – Ruminants. Goals and Objectives Understand the influence of parasitism on...
Endoparasites – Endoparasites – Ruminants Ruminants
Goals and Objectives
• Understand the influence of parasitism onproduction
• Become familiar with the types of parasitesafflicting agricultural animals
• Understand the public health implications ofselected parasites
• Understand the basic principles of parasitecontrol and treatment
Parasitology - Ruminants
• Economic Losses– Poor ADG
– Abortion
– Decreased conception
rates
– Death
• Public Health– Zoonosis
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 of
internal parasite control for productioninternal parasite control for production
efficiency.efficiency.
-Deworming is now standard practice on beef-Deworming is now standard practice on beef
and dairy farms.and dairy farms.
-Must have correct product at the correct-Must have correct product at the correct
time.time.
Definition
• Types of relationships between organism and
host
– Commensal ‐ one benefits without harming the
other
– Mutualism ‐ both participants benefit
– Parasitism ‐ one benefits at the expense of the
other
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 – Indications
Purpose 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
Modified Wisconsin Sugar FlotationModified Wisconsin Sugar FlotationMethodMethod
Add 15 - 17 cc sugarAdd 15 - 17 cc sugar
solution to samplesolution to sample
Modified Wisconsin Sugar FlotationModified Wisconsin Sugar FlotationMethodMethod
Place 3 - 5 grams ofPlace 3 - 5 grams of
fecal material into a 3fecal material into a 3
oz paper cupoz paper cup
(About a thimble full)(About a thimble full)
Modified Wisconsin Sugar FlotationModified Wisconsin Sugar FlotationMethodMethod
Stir solution & fecalStir solution & fecal
sample to an evensample to an even
consistency.consistency.
Modified Wisconsin Sugar FlotationModified Wisconsin Sugar FlotationMethodMethod
Stir solution & fecalStir solution & fecal
sample to an evensample to an even
consistency.consistency.
Modified Wisconsin Sugar FlotationModified Wisconsin Sugar FlotationMethodMethod
Use a tongue depressor,Use a tongue depressor,
press as much materialpress as much material
through strainer asthrough strainer as
possible.possible.
Modified Wisconsin Sugar FlotationModified Wisconsin Sugar FlotationMethodMethod
1. Pour into 15cc taper1. Pour into 15cc taper
bottom centrifuge tube.bottom centrifuge tube.
2. Centrifuge in swinging 2. Centrifuge in swinging arm centrifuge at 900arm centrifuge at 900
rpm for 5 – 7 minutes.rpm for 5 – 7 minutes.
Modified Wisconsin Sugar FlotationModified Wisconsin Sugar FlotationMethodMethod
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 mm
cover slip on tubecover slip on tube
and leave in placeand leave in place
for 2 - 4 minutes.for 2 - 4 minutes.
Modified Wisconsin Sugar FlotationModified Wisconsin Sugar FlotationMethodMethod
Lift cover slip upwardLift cover slip upward
& place on slide& place on slide
Modified Wisconsin Sugar FlotationModified Wisconsin Sugar FlotationMethodMethod
Use microscope toUse microscope to
scan entire cover slipscan entire cover slip
for 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 large
intestine
• 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 (brown stomach worm)– 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 and
humans
• Ruminants eat eggs passed in feces of canids
or 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
• Eggs: are heavy sedimentation is recommended
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=6196
• 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/index.html#fecal• http://www.sheepandgoat.com/HairSheepWorkshop/
parasitism.html