Joan Burke, Ph.D. Small Ruminant Integrated Parasite Control FAMACHA & Smart Drenching

8/8/2019 Joan Burke, Ph.D. Small Ruminant Integrated Parasite Control FAMACHA & Smart Drenching

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Small Ruminant IntegratedSmall Ruminant Integrated

Parasite ControlParasite ControlFAMACHAFAMACHA

and Smart Drenchingand Smart Drenching

Southern Consortium for Small Ruminant

Parasite Control


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TopicsTopics

The problem

The parasites; where we are and why

Biology of important GI Parasites Dewormers a quick review

What can we do?

Smart Drenching

FAMACHA


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The Big Problem facingThe Big Problem facing

producersproducers

Anthelmintic (dewormer) resistance is

considered a major threat to the

current and future control of parasites

of ruminants and horses

Worldwide phenomena

The prevalence ofmulti-drug resistantworms is extremely high in many areas

of the world


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What is Resistance?What is Resistance?

The ability of certain worms in a population to

survive drug treatments that are generally

effective against the same worm species and

stage of infection

Caused by changes in levels of resistance

genes carried by worms in a population

Result of drug treatment that produces genetic

selection of resistant worms in a population of

worms


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Dewormer ResistanceDewormer ResistanceHistory of the ProblemHistory of the Problem Age of modern dewormers

Effective, broad-spectrum, cheap, safe

Over-reliance on dewormers

Addiction to drugs, improper use of dewormers Loss of common sense approaches

Belief there will always be a new drug

No new drug classes introduced since 1981

We have what we have !!!!

New anthelmintic announced by Novartis in 2007, but

will not be available for many years to come


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Where Do ResistantWhere Do Resistant

Worms Come From ??Worms Come From ?? Resistance is an inevitable consequence of using any particular drug

to kill worms

Resistant worms worms that can survive drug treatment,

actually exist prior to the first use of a drug

Treatment eliminates worms whose genes render themsusceptible to the drug

Parasites that are resistant survive and pass on their resistant

genes to their offspring

Over time with continued treatment, more and more resistant

worms build up in the population

High level of animal movement spreads resistant worms (Animals

shipped from state to state or country to country carry their worm

infections with them)


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Parents

R

es

ista

nt

Susce

ptib

leNext Generation

Drug Treatment

Res

ista

nt

Selection forDrugResistance


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Perc

ent o

f

Worm

sthat

Are

Resi s

tan t

Changes in Resistance GenesChanges in Resistance Genes

in Response to Drug Selectionin Response to Drug Selection

Worm Generations(exposed to repeated treatments)

Detection level with tests

Apparent as a clinical problem


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Southern Consortium for SmallSouthern Consortium for Small

Ruminant Parasite ControlRuminant Parasite ControlDr. Ray Kaplan, UGA, GAMr. Bob Storey, UGA, GA

Ms. Sue Howell, UGA, GA

Dr. Lisa Williamson, UGA, GA

Dr. Tom Terrill, FVSU, GA

Dr. Will Getz, FVSU, GA

Dr. Seyedmehdi Mobini, FVSU, GA

Dr. Jim Miller, LSU, LA

Dr. Joan Burke, USDA-ARS, AR

Dr. Jorge Mosjidis, AU, AL

Dr. Elide Valencia, UPR, PR

Dr. Anne Zajac, VT, VA

Dr. Stephan Wildeus, VSU, VA

Dr. Steve Hart, LU, OK

Dr. Jean-Marie Luginbuhl, NC St, NC

Dr. Jim Muir, TAMU, TX

Dr. Dahlia Jackson, DSU, DE

Dr. Niki Whitley, UMES, MDMs. Susan Schoenian, WMREC, MD

Mr. Stuart Weiss, UVI, St. Croix

Ms. Linda Coffey, NCAT, ATTRA

Ms. Margo Hale, NCAT, ATTRA

Dr. Adriano Vatta, OVI, South Africa

Dr. Jan van Wyk, U Pretoria South Africa

Dr. Gareth Bath, U Pretoria South Africa

A Fresh Approach Is Needed!A Fresh Approach Is Needed!

www.scsrpc.orgwww.scsrpc.org

www.wormx.orgwww.wormx.org
http://www.scsrpc.org/http://www.scsrpc.org/http://www.wormx.org/http://www.wormx.org/http://www.wormx.org/http://www.scsrpc.org/


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SCSRPC ProjectsSCSRPC Projectswww.scsrpc.org www.wormx.orgwww.scsrpc.org www.wormx.org

FAMACHA validation and evaluation

Copper-oxide wire particle bolus

Condensed tannin containing forage

Integrated approaches

Host resistance studies

Nematophagous fungi

Vaccines


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Gastrointestinal NematodesGastrointestinal Nematodes

(Worms) of Sheep and Goats(Worms) of Sheep and Goats

Most Important Species:

1. Haemonchus contortus ***

Barberpole worm1. Teladorsagia (Ostertagia) circumcincta

Brown stomach worm

1. Trichostrongylus colubriformis Bankrupt worm

1. +/- Nematodirus


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Life Cycle of GI Worms

L2L3

L1L3

L3
http://mirror-us-ga1.gallery.hd.org/_exhibits/natural-science/_more2007/_more04/ram-sheep-on-farm-in-grass-field-at-Neals-Farm-Checkendon-Oxfordshire-England-4-DHD.jpg


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Haemonchus contortusHaemonchus contortus(Barber Pole Worm)(Barber Pole Worm)

PUBLIC ENEMY NUMBER ONEfor small ruminant farmers

Literally a blood sucking worm

Very prolific one adult female can produce 5000 eggs per day

Short life cycle about 3 weeks from time of infection until eggs are

produced

Preys on the weak, young, pregnant, or lactating animal

Developing resistance to all classes of dewormers


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Haemonchus contortusHaemonchus contortus


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Bottle Jaw

Anemia


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Why isWhy is H. contortusH. contortusSuchSuch

a Problem ???a Problem ???

Evolved in tropics

thrives in warm/wet climates

Long transmission season in southern states Short life cycle

Goats acquire only partial immunity

Immunity is slow to develop in sheep Kids and Lambs are highly susceptible

Immunity wanes around time of kidding/lambing


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Why isWhy is H. contortusH. contortusSuchSuch

a Problem ???a Problem ???

Very prolific each female worms

produces ~ 5,000 eggs per day

500 worms 2.5 million epd per animal 50 goats 1 billion eggs per week


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Goats Were Never Intended toGoats Were Never Intended to

Live (and Graze) in a WarmLive (and Graze) in a Warm

Humid ClimateHumid Climate


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TeladorsagiaTeladorsagia((OstertagiaOstertagia)) circumcinctacircumcincta

(Brown stomach worm)(Brown stomach worm)

Most important parasite of sheep/goats in cool

climates (e.g., Scotland, NZ)

Tiny worms develop in gastric glands of

stomach (abomasum)

as worms grow they destroy the glands

affects appetite, digestion and nutrient

utilization Clinical symptoms

diarrhea, reduced appetite, weight loss


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TeladorsagiaTeladorsagiainin

gastric glandsgastric glands

Damage toDamage to

stomach wallstomach wall


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Resistance RevisitedResistance Revisited


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So far.So far.

Weve briefly discussed resistance

Weve talked about parasite life cycles

Weve talked about drugs in general

and farms not having any dewormers

that still work


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So, How did we get here?So, How did we get here?


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By doing what we thoughtBy doing what we thought

was right, based on whatwas right, based on what

we knewwe knew

(what was recommended by(what was recommended bythe experts)the experts)


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The Traditional ApproachThe Traditional Approach

to Parasite Managementto Parasite Management

Treated entire herd

Dewormed by the calendar

Rotated dewormers regularly

One Pasture may be only option

Over crowding/grazing

If multiple pastures, dewormed at move to new

pasture

Unknowingly purchased resistant worms

Wh t C R i t


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What Causes ResistanceWhat Causes Resistance

To Dewormers ???To Dewormers ???

Lack of Refugia Refugia = the proportion of the worm population that

is not selected by drug treatment

Worms in untreated animals

Eggs and larvae on pasture

Provides pool of sensitive genes

Dilutes resistant genes Considered the most important factor in the

development of drug resistance

Wh t C R i t


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What Causes ResistanceWhat Causes Resistance

To Dewormers ???To Dewormers ???

1. Treatment strategies that refugia Examples:

Treating and moving to clean pasture

Treating when few larvae are on the pasture (drought) Treating all animals at same time

1. Frequent Treatments > 3 treatments per year

1. Under dosing


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Resistance is InevitableResistance is InevitableWhat Can We Do ???What Can We Do ???

Resistance is a natural biological

consequence of drug treatment

Rate of development of resistance is within

our control and can be greatly reduced

Goal = Preserve drug

efficacy for as long as possible

Increase refugia

Selective treatment

Cl f A th l i ti


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Classes of AnthelminticsClasses of Anthelmintics

(Dewormers)(Dewormers)

1. Benzimidazoles (BZ) fenbendazole (FBZ; Panacur, Safegard)

albendazole (ABZ; Valbazen)

1. Avermectin / Milbemycins ivermectin (IVM; Ivomec)

moxidectin (MOX; Cydectin)

1. Imidazothiazoles / Tetrahydropyrimidines levamisole (LEV; Tramisole, Levasole), morantel

(MOR; Rumatel, Golden Blend, others)


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Resistance Occurs WithinResistance Occurs Within

Classes of AnthelminticsClasses of Anthelmintics

Resistance to one drug in a class

confers resistance to all others

same mechanism of action

Exceptions to this are due to

differences in potency and are onlytemporary

f G


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Prevalence of Resistance on Goarevalence of Resistance on Goa

Farms in Georgia (2001)Farms in Georgia (2001)

Albendazole (Valbazen) & Ivermectin (Ivomec) > 90%

Levamisole (Tramisole)

~ 30%

Moxidectin (Cydectin)

none detected in 2001

40% of farms in 2003 (where MOX was usedas predominant dewormer

Evaluation of prevalence and clinical implications ofEvaluation of prevalence and clinical implications of

anthelmintic resistance in gastrointestinal nematodes ofanthelmintic resistance in gastrointestinal nematodes of

goats. Mortensen, et al.,goats. Mortensen, et al.,JAVMA,JAVMA, 223(4):495-500 (2003)223(4):495-500 (2003)

P l f R i tP l f R i t


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Prevalence of Resistance onPrevalence of Resistance on

Sheep & Goat Farms (SE USA)Sheep & Goat Farms (SE USA)

(Accumulated Data from 2002-2006)(Accumulated Data from 2002-2006)

Dewormer Prevalence of

ResistanceBenzimidazole 98

Levamisole 54

Ivermectin 76Moxidectin 24

MDR all 3 classes 48

MDR to all 3 classes + Moxidectin 17


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Prevalence of AnthelminticPrevalence of Anthelmintic

Resistance in Sheep:Resistance in Sheep:

New Zealand and AustraliaNew Zealand and Australia Australia (WA)

IVM 60%

ABZ 99%

LEV 99%

New Zealand

IVM 25%

ABZ 41%

LEV 24%

Triple resistant 7%Moxidectin (Cydectin) resistance still is relatively

uncommon (but it is being increasingly reported)


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TotalTotal Anthelmintic FailureAnthelmintic Failure

A near-term possibility on many sheep andgoat farms in many areas Many farms are down to their last drug

Malaysia and South America Some farms reporting TOTAL drench failure

20% death losses per year

First case in USA diagnosed by Dr. Kaplanslaboratory in 2005 now seeing more cases Recent study -- TAF on 17% of farms in SE

Future viability of SR industries is threatened


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Total Anthelmintic Failureon a Meat Goat Farm in Arkansas, USA

Drench Control Levamisole Albendazole Ivermectin Moxidectin

Number 15 14 14 11 15

Arith. Mean 2490 557 979 2018 563

% Reduction 78 61 19 77

Upper 95% CL 88 79 57 88

Lower 95% CL 57 26 0 57

Drench effectiveness Resistant Resistant Resistant Resistant

Wh D t it S AWh D t it S A


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Why Doesnt it Seem AsWhy Doesnt it Seem As

Bad As it Sounds ???Bad As it Sounds ??? Your neighbor may be worse off than you US Data is from the southern states

may be less resistance in the north and west

Resistance as defined is a population measure Not all worms on farm are resistant

Killing some worms will relieve disease symptoms Removing 50% of worms gives clinical improvement

This gives the appearance that treatment was effective Animals will require treatment again very soon

Obvious treatment failure only recognized onceresistance is severe

Wh t D Thi M F ThWh t D Thi M F Th


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What Does This Mean For TheWhat Does This Mean For The

Small Ruminant Industry ???Small Ruminant Industry ???

Dewormers can no longer be thought of as a cheap input to

maximize productivity

Extremely valuable and limited resources

Requires a medically-based approach to treatment Control ofHaemonchus must be practiced with an eye to the

future

Reality = long-term control ofHaemonchus will only be

possible if dewormers are used intelligently withprevention of resistance as a goal

Reduced-chemical and non-chemical approaches are

needed

Sl i dSl i d


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Slowing downSlowing down

ResistanceResistance

Given that resistance is inevitable and

resistance is forever, how do we slow it

down?

Reduce genetic selection pressure

Maintaining a pool of sensitive genes

REFUGIA Treat individuals, not herds

Concept known as..


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Smart DrenchingSmart Drenching

Using what we have learned to

develop deworming strategies that

maximize the effectivenessoftreatments while at the same time

decreasing the rate at which we

create drug resistance

C t f S tComponents of a Smart


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Components of a SmartComponents of a Smart

Drenching ProgramDrenching Program

Know the resistance status of theherd/flock

Sound pasture management Keep resistant worms off the farm

Administer the proper dose

Utilize host physiology Selective treatment -- FAMACHA

K th R i tKnow the Resistance


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Know the ResistanceKnow the Resistance

Status of the FlockStatus of the Flock

Perform FECRT or DrenchRite

Repeat every 2 years

When resistance is recognized in earlystages

Drug can still be used

Must be managedappropriately

Use ProperUse Proper


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Use ProperUse Proper

TechniqueTechnique

Ensure proper dose is delivered

Proper technique when drenching

sheep and goats is very important

drench should be delivered over the back of

the tongue

critical that full dose lodges in the rumen

drench delivered to the mouth maystimulate esophageal groove to close

significant drench bypasses the rumen

efficacy is reduced

Images courtesy ofpremier1supplies.com

D SD S


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Dewormer SavvyDewormer SavvyGive theGive the RightRightDoseDose

Goats: 2X sheep dose

exceptions

Levamisole (1.5X)

Moxidectin

injectable (1X)


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Dose According to WeightDose According to Weight

Weigh scales

Weight tapes Only accurate

for dairy goats

inaccurate inmeat breeds

Utili H t Ph i l tUtilize Host Physiology to


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Utilize Host Physiology toUtilize Host Physiology to

Maximize Drug EfficacyMaximize Drug Efficacy

Restrict feed intake for 24 hours prior totreatment (BZ and ivermectin)

Withholding feed decreases digesta flow rate

leading to an increase in drug efficacy Never in late pregnancy

Repeat dose in 12 hours (BZ)

These simple measures can substantiallyimprove efficacy when resistance is present and

can help to delay resistance if not yet present

R t ti f DR t ti f D


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Rotation of DewormersRotation of Dewormers

Is This a Good Idea ???Is This a Good Idea ???

Has been promoted for many years

Although recommended for many years

there are new arguments against usingrotation

Rotation is NOT a replacement for properresistance prevention measures

On many farms, rotation is not possiblebecause of resistance

Rotation of De ormers IsRotation of Dewormers Is


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Rotation of Dewormers IsRotation of Dewormers Is

A Bad IdeaA Bad Idea

Creates a false presumption among vetsand livestock owners that they have a

bona-fide resistance prevention program

Rotation will mask resistance Resistance develops slowly to all drugs

simultaneously

1 effective drug will cover for another Few livestock owners realize they have

resistance problems until it is too late


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Drug CombinationsDrug Combinations

Use of combinations of drugs simultaneously have been

shown to

Decrease rate with which resistance develops

Increase the effectiveness of treatment

Drugs not useful on their own can achieve reasonable

therapeutic results if combined

BUT very dangerous if:

Do not build refugia into system

Do not do efficacy testing to monitor resistance situation


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Selective TreatmentSelective Treatment

FAMACHA

ForH. contortus only

For other GI worms

FEC Age

Body condition

Production level Symptoms

Short term weight gain

Concept BehindConcept Behind


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Concept BehindConcept Behind

Selective TreatmentSelective Treatment

Parasites are not equally distributed ingroups of animals

Overdispered / aggregated distributions

20-30 % of animals harbor most of worms Few animals are responsible for most of egg

output

Number of Worms

Freq

Di t ib ti f FEC i G t H d


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Distribution of FEC in Goat Herds

0

4000

8000

12000

16000

20000

FEC

0

1000

2000

3000

4000

Individual Goats

FEC

33% of Goats

80% of Eggs

Treating high 33%

Greatly ReducesDaily Pasture

Contamination With

Eggs

Treating 1/3 ofgoats gives just

as good control

as treating the

entire herd

230 M

33%

46 Million

66%

Wh t H If W T t O l th Hi h 33% ???


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33% of Goats

< 5% of Eggs

0

400

800

1200

1600

2000

FEC

0

100

200

300

400

Individual Goats

FE

C

Treating high 33% with a

drug that causes a 99%FECR reduces daily

pasture contamination

with eggs by 80%

Following treatment

> 95% of eggs are being

shed by untreated goats

= REFUGIA

Less Resistance

What Happens If We Treat Only the High 33% ???


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So, how do we easilydetermine who to treat?


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FAMACHAFAMACHA

FaFafafaMaMalanslansChaChartrt


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The FAMACHAThe FAMACHA SystemSystem

Eye color chart with five

color categories

Compare chart with color of

mucous membranes ofsheep or goat

Classification into one of five

color categories: 1 not anemic

5 -- severely anemic


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How Does FAMACHA Work ??How Does FAMACHA Work ??

Since the primary impact ofH.

contortus is anemia, one can indirectly

measure parasite burden (and need fortreatment) by measuring anemia

Only useful where H. contortus is theprimary parasite species


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AnemiaAnemia

Definition a reduction below normal in thenumber or volume of red blood cells in theblood

Symptoms depend on degree/severity

Sub-mandibular Edema (Bottle Jaw)

Unthrifty Condition

Poor BCS

Broken coatExercise/Heat intolerance

Pale mucus membranes


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Severe AnemiaSevere Anemia


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Haemonchus contortusHaemonchus contortus

Heavy burden can result in the loss of cup

or more of blood per day

The total blood volume of a goat makes up

approximately 1/12th its total body weight. A 120 pound goat => 10 pounds of blood => 4.5

kg of blood => 4.5 liters or 4,500 ml of blood

volume. 120 ml in cup => 50% blood loss in 37

days

Conjunctiva colorConjunctiva color


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Conjunctiva colorConjunctiva color

relationship to Anemiarelationship to Anemia

28Red1

Hematocrit

Range (%)

Color

Classification

Clinical

Category

1)


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2) Pull down lower eyelid with other thumb

1) Place gentle downwardpressure on eye with upper

thumb

3) Read color ofeye on mucousmembranes of

lower eyelid


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FAMACHAFAMACHA System rulesSystem rules

Score using the chart

Evaluate in bright light

(sunlight)

Be quick

Score both eyes

Use higher score if eyes

differ

What Do I Do With TheWhat Do I Do With The


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What Do I Do With TheWhat Do I Do With The

Results?Results?

Always treat goats

and sheep in

categories4 and 5

Dont treat 1s and

2s

When should youtreat the 3s?


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Animals in Category 3Animals in Category 3

Treat when

>10% of herd scores in categories 4 or 5

Young animals

Ewes/does (pregnant or lactating) Animals in poor body condition

If any concern about animals general health

and well being

Consider using less effective drugs

H Oft D I M it


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How Often Do I MonitorHow Often Do I Monitor

If


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How oftenHow often

If>10% of flock/herd scores in

categories 4 and 5:

Recheck weekly

Treat the 3s

Change pastures (if possible)

P ti


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PrecautionsPrecautions

FAMACHA only applicable where

Haemonchus is the main worm

causing clinical disease Conjunctival redness can be

caused by eye disease,

environmental irritants, andsystemic disease

P ti


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Precautions.Precautions.

Dont use it as a sole criteria for

whether or not to drench

If you see other symptoms such as bottle

jaw, you know you need to drench

Look at all available signs

Body condition score

Coat condition Consistency of feces

Heat/exertion intolerance

Th F h C dTh F h C d


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The Famacha CardThe Famacha Card

Store in dark placewhen not in use

Replace card after 12months use

Keep a spare card in

a light protectedplace

Wh FAMACHAWh FAMACHA


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Why use FAMACHAWhy use FAMACHA

Decreased Worm burdens

Creates Refugia

Decreased development of

resistance Saves money

Identifies animals that need less frequent

deworming -- keep for breeding

Identifies animals that need more frequent

deworming -- cull

R b R f i (I R f )R b R f i (I R f )


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Remember Refugia (In Refuge)Remember Refugia (In Refuge)

Untreated animals

harbor susceptible

worms

Dilutional effect

Resistance

develops more

slowly

Keep Herd and IndividualKeep Herd and Individual


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Keep Herd and IndividualKeep Herd and Individual

Records!!!!Records!!!!

Example Herd AnemiaExample Herd Anemia


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Example Herd AnemiaExample Herd Anemia

RecordRecord


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Control Parasites by Determining

Which parasites are present

When they are being transmitted

How they survive

Which anthelminthics are effective

What dose is required for host species

When is the most appropriate time to

administer anthelminthics or use otheralternative control methods


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Thanks to The 2004 World Sheep and Wool

Congress For Use of the Slide Design

Produced by

Ray Kaplan, DVM, PhD, Dip EVPC,

Bob Storey, MS, RVTLisa Williamson, DVM, MS, Dip ACVIM

University of Georgia

Jim Miller, DVM, MPVM, PhD

Louisiana State University

With contributions from other members of the SCSRPC

Questions ???


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Questions ???

Joan Burke, Ph.D. Small Ruminant Integrated Parasite Control FAMACHA & Smart Drenching

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