Endoparasites – 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 Losses -Producer Unaware of parasite damage estimate annual parasite-related losses to the livestock industry at more than $100 million - Timing & Frequency of treatments -Choice of dewormer -Parasites have greatest impact on high producing animals.

What is ruminants Parasitism? It is a herd disease It is a production disease It develops during grazing 99% of all pastures contaminated

Level of Parasitism Related To Age of animals Pasture contamination level Stocking rate of animals Grazing environment & Weather Immune status of animals

Deworming strategy -Producers understand importance of internal parasite control for production efficiency. -Deworming is now standard practice on beef and dairy farms. -Must have correct product at the correct 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

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 a Dairy/Meat Operation First determine the approximate level of parasitic contamination

1.- High Parasite Contamination Level Cows grazing pasture during lactation When rotational grazing is practiced

2. Moderate Parasite Contamination Level Cows grazing pasture only during dry period Cows with access to an exercise lot only (with some grass)

Low Parasite Contamination Level Cows with access to dirt dry lot

4. Extremely Low Parasite Contamination Level Cows in total confinement Cows on a concrete dry lot

Summary Strategy For Lactating Cows Parasites have been shown to decrease milk production in early lactation Identify parasite contamination levels in each dairy operation Design deworming program based on individuals or herd treatment relative to contamination levels

Parasite – Indications Purpose of the tests Direct-aids in the detection of certain protozoan trophozoites. Flotation method-eggs in feces are mixed with flotation solution that will cause them to float to the top. Baerman Funnel Technique-larva migrate to the bottom. Used to detect lungworms in ruminants. Centrifugation technique-will detect parasitic eggs when other techniques do not, specially heavier eggs that will not float. MIF (merthiolate iodine formalin) –satins and preserves protozoans & larvae

Modified Wisconsin Sugar Flotation Method Technique Samples can be stored if refrigerated Sugar solution – One pound of sugar. – Add to 12 oz(355cc) of hot water. Slides can be refrigerated for reading later Materials Sugar solution & dispensing syringe Tea strainer 3/5 oz dixie cups Tongue depressors Taper bottom 15cc tubes Test tube rack Microscope slides & 22x22 mm cover slips 22

Modified Wisconsin Sugar Flotation Method Add 15 - 17 cc sugar solution to sample 23

Modified Wisconsin Sugar Flotation Method Place 3 - 5 grams of fecal material into a 3 oz paper cup (About a thimble full) 24

Modified Wisconsin Sugar Flotation Method Stir solution & fecal sample to an even consistency. 25

Modified Wisconsin Sugar Flotation Method Stir solution & fecal sample to an even consistency. 26

Modified Wisconsin Sugar Flotation Method Use a tongue depressor, press as much material through strainer as possible. 27

Modified Wisconsin Sugar Flotation Method 1. Pour into 15cc taper bottom centrifuge tube. 2. Centrifuge in swinging arm centrifuge at 900 rpm for 5 – 7 minutes. 28

Modified Wisconsin Sugar Flotation Method 1. Place tube in rack and top off with sugar solution to form a meniscus. 2. Place 22x22 mm cover slip on tube and leave in place for 2 - 4 minutes. 29

Modified Wisconsin Sugar Flotation Method Lift cover slip upward & place on slide 30

Modified Wisconsin Sugar Flotation Method Use microscope to scan entire cover slip for egg count 31

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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 – 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); Fascioloides magna – 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=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