bovine neosporosis benjamin (bj) newcomer, dvm [email protected] february 6, 2009

Bovine Bovine NeosporosisNeosporosis

Benjamin (BJ) Newcomer, Benjamin (BJ) Newcomer, DVMDVM

[email protected]@auburn.edu

February 6, 2009February 6, 2009

OutlineOutline

BackgroundBackground Life cycleLife cycle TransmissionTransmission Clinical presentationClinical presentation DiagnosticsDiagnostics Prevention/controlPrevention/control

HistoryHistory

First recognized in dogs in 1984First recognized in dogs in 1984– encephalomyelitis and myositis in 6 encephalomyelitis and myositis in 6

boxer puppiesboxer puppies Onset: 2-6 mo oldOnset: 2-6 mo old Extensive inflamm.Extensive inflamm.lesions in CNS andlesions in CNS andskeletal muscleskeletal muscle Neg. toxo titersNeg. toxo titers

HistoryHistory

First associated with cattle in First associated with cattle in 1987 abortion storm1987 abortion storm– 29 abortions over 5 months29 abortions over 5 months

1987 - weak calf born 1987 - weak calf born assoc with protozoan dis.assoc with protozoan dis.

– negative for negative for T. gondiiT. gondii– negative for Snegative for Sarcocystis sparcocystis sp..

HistoryHistory

In 1988, determined to be a new In 1988, determined to be a new genus and species genus and species – Neospora caninumNeospora caninum

Often misdiagnosed as Often misdiagnosed as Toxoplasma gondiiToxoplasma gondii

Stillborn calf in 1974Stillborn calf in 1974 Toxoplasma

Affected Affected speciesspecies

DefinitivDefinitive hoste host

Multiple Multiple abortionabortion

ss

N. N. caninucaninu

mm

T. T. gondiigondii

DistributionDistribution

Found in 6 continents Found in 6 continents Endemic in CA since 1984Endemic in CA since 1984 Primary abortifacientPrimary abortifacient

– CaliforniaCalifornia– New ZealandNew Zealand– The NetherlandsThe Netherlands

Life cycleLife cycle

Typified by 3 infectious stagesTypified by 3 infectious stages– oocystsoocysts– tachyzoitestachyzoites– tissue cysts (bradyzoites)tissue cysts (bradyzoites)

Definitive hosts:Definitive hosts:– dogsdogs– coyotescoyotes– other canids also?other canids also?


Definitive hosts shed Definitive hosts shed unsporulated oocysts >4 days unsporulated oocysts >4 days after ingestionafter ingestion

Variable sheddingVariable shedding– Up to 4.5x10Up to 4.5x106 6 oocysts/gram of fecesoocysts/gram of feces– 1 day to 4 months1 day to 4 months

Life CycleLife Cycle

Puppies shed higher # oocystsPuppies shed higher # oocysts Shedding: bovine cysts > murine Shedding: bovine cysts > murine

cystscysts Corticosteroids increase sheddingCorticosteroids increase shedding

– immunocompromised dogs? immunocompromised dogs?

Life CycleLife Cycle

After 1-3 days, oocysts After 1-3 days, oocysts sporulatesporulate– form two sporocystsform two sporocysts– each contain 4 sporozoiteseach contain 4 sporozoites


Sporulated oocysts ingested by Sporulated oocysts ingested by intermediate hosts (cattle)intermediate hosts (cattle)

Sporozoites released in GIT and Sporozoites released in GIT and penetrate GIT liningpenetrate GIT lining


Tachyzoites spread throughout Tachyzoites spread throughout bodybody– neural tissueneural tissue– muscle tissue, myocardiummuscle tissue, myocardium– placenta, fetusplacenta, fetus

Once infected, always infectedOnce infected, always infected


When faced with a strong immune When faced with a strong immune response, tachyzoites encyst as response, tachyzoites encyst as bradyzoites bradyzoites

Cysts are minimally inflammatoryCysts are minimally inflammatory Remain latent until host is Remain latent until host is

immunosuppressedimmunosuppressed Cysts reinfect definitive host if Cysts reinfect definitive host if

consumedconsumed

Encysted bradyzoitesEncysted bradyzoites

Thick-walled cysts differentiate N. caninum from T. gondii

www.cmgm.stanford.edu

www.k-state.edu

www.liv.ac.uk

Dubey JP, Lindsay DS.Vet Parasitol. 2;67(1-2):1-59.

Transmission in cattleTransmission in cattle

Horizontal infection Horizontal infection – 1-2% of infections in cattle1-2% of infections in cattle

Cow-to-cow transmission not Cow-to-cow transmission not observedobserved– no excretion of live organismsno excretion of live organisms

Prevalence doesn’tPrevalence doesn’t

increase with ageincrease with age

TransmissionTransmission

High efficacy of transplacental High efficacy of transplacental infectioninfection– lower efficacy in low prevalence herdslower efficacy in low prevalence herds

““Silent infections”Silent infections” Monitor by precolostral samplingMonitor by precolostral sampling

– false negatives (?)false negatives (?)


Experimental transmission in Experimental transmission in colostrumcolostrum– N. caninum N. caninum tachyzoites or DNA tachyzoites or DNA – not successful in dogsnot successful in dogs

Not believed to be a natural route Not believed to be a natural route of transmissionof transmission


N. caninumN. caninum DNA has been DNA has been identified intermittently in semenidentified intermittently in semen

Sexual transmission produced Sexual transmission produced experimentally with 10experimentally with 1044 tachyzoitestachyzoites– dose-dependant responsedose-dependant response

Not believed to be Not believed to be transmitted naturallytransmitted naturally

www.neosporosis.com

WildlifeWildlife

www.vetmed.illinois.edu

Potential definitive Potential definitive hostshosts

Potential intermediate Potential intermediate hostshosts

So what?So what?

PrevalencePrevalence

Neosporosis historically a dairy Neosporosis historically a dairy diseasedisease– sampling bias (?)sampling bias (?)

Evidence of infection common in Evidence of infection common in both beef and dairy herdsboth beef and dairy herds

Prevalence - DairyPrevalence - Dairy

15-40% of dairy cattle tested (+) 15-40% of dairy cattle tested (+) – in multi-herd studiesin multi-herd studies

Up to 100% (+) within herdsUp to 100% (+) within herds Up to 100% of herd in endemic Up to 100% of herd in endemic

areasareas

Prevalence - DairyPrevalence - Dairy

Prevalence study on 3 GA dairiesPrevalence study on 3 GA dairies Milk samples assayed by Western Milk samples assayed by Western

blotblot Results:Results:

Farm Positive/Total %

A 28/115 24.4

B 30/139 21.6

C 47/73 64.4

TOTAL 105/327 31.1

Ortega, Y.R. et al., Vet Parasitol. 2007(144):353-355.

Prevalence - BeefPrevalence - Beef

5-23% of beef cattle tested (+)5-23% of beef cattle tested (+) Up to 67% (+) within herdsUp to 67% (+) within herds

– avg 19%avg 19% 36-100% herds positive36-100% herds positive

Dairy vs. BeefDairy vs. Beef

Serology data difficult to compareSerology data difficult to compare– different methods and cut-off pointsdifferent methods and cut-off points

Multi-national studyMulti-national study– Bartels, et. al, Bartels, et. al, Vet ParasitolVet Parasitol. 2006 137:17-. 2006 137:17-

2727 – >1000 herds, ~25,000 head>1000 herds, ~25,000 head

Random herds: all cattle Random herds: all cattle >>2 yrs 2 yrs testedtested– standardized ELISAstandardized ELISA

Herd type

# tested # positive Prevalence (%)

Sweden Dairy 112 34 30

Germany Beef 106 43 41

Dairy 100 50 50

The Netherlands

Beef 82 58 71

Dairy 108 86 80

Spain Beef 372 171 46

Dairy 291 184 63

Prevalence - DogsPrevalence - Dogs

Cheadle MA, Lindsay DS, Blagburn BL.Cheadle MA, Lindsay DS, Blagburn BL.

Vet ParasitolVet Parasitol. 1999; 85(4):325-30.. 1999; 85(4):325-30. 1077 serum samples from 1077 serum samples from

US/CanadaUS/Canada IFAT testing at single labIFAT testing at single lab

9/158 (6%)14/190 (7%)

30/313 (10%)

3/145 (2%)

Financial lossesFinancial losses

$35 million in CA annually$35 million in CA annually $25 million in TX beef industry$25 million in TX beef industry 30,000-60,000 pregs/year in Canada30,000-60,000 pregs/year in Canada

$25-35 per head in $25-35 per head in

herds with 20% herds with 20%

prevalenceprevalence

Clinical PictureClinical Picture

Reproductive lossesReproductive losses Decreased milk productionDecreased milk production Decreased weight gainDecreased weight gain Premature cullingPremature culling

Reproductive lossesReproductive losses

4 manifestations of disease4 manifestations of disease1.1. Early embryonic deathEarly embryonic death

2.2. AbortionAbortion

3.3. Stillbirths or weak calves born aliveStillbirths or weak calves born alive

4.4. Apparently healthy calfApparently healthy calf

Depends on pregnancy status Depends on pregnancy status and stage of gestationand stage of gestation


When a naïve, open cow is When a naïve, open cow is infected, development of CMI infected, development of CMI leads to CNS cystsleads to CNS cysts– seroconversionseroconversion

This cow poses a low risk of This cow poses a low risk of infection to her herdmatesinfection to her herdmates


If a cow is <3 months pregnant, If a cow is <3 months pregnant, early embryonic death may occurearly embryonic death may occur– through pro-inflammatory cytokines through pro-inflammatory cytokines

active at the placental connectionactive at the placental connection

www.drostproject.vetmed.ufl.edu


Cows in mid-gestation most Cows in mid-gestation most susceptiblesusceptible

Cow’s immune system down Cow’s immune system down regulatedregulated– placental type 2 cytokine on T-cellsplacental type 2 cytokine on T-cells

Calves’ immune system incompetentCalves’ immune system incompetent Tachyzoites infect CNS Tachyzoites infect CNS

– abortionabortion– stillbirth, CNS deficitsstillbirth, CNS deficits

AbortionAbortion

Risk of abortion is 4-7x higher in Risk of abortion is 4-7x higher in seropositive cowsseropositive cows

Cows that abort onceCows that abort once– 6 times more likely to abort again 6 times more likely to abort again

than seropositive cows w/out than seropositive cows w/out abortionabortion


Cows that abort are not clinically illCows that abort are not clinically ill 4-6 months of gestation4-6 months of gestation Aborted fetus usually autolyzedAborted fetus usually autolyzed Placentas not retainedPlacentas not retained Two patternsTwo patterns

– endemicendemic– epidemicepidemic

Endemic abortionEndemic abortion

Persistent elevation greater than Persistent elevation greater than 5% in annual abortion rate5% in annual abortion rate

Abortions occur throughout the Abortions occur throughout the yearyear

Abortions in both cows and heifersAbortions in both cows and heifers Abortion rate due to Abortion rate due to N. caninumN. caninum

– 10-17% on two CA dairies10-17% on two CA dairies

Epidemic abortionEpidemic abortion

Abortion outbreaksAbortion outbreaks 30% of pregnant cattle over 30% of pregnant cattle over

several monthsseveral months Likely due to a horizontal Likely due to a horizontal

transmission eventtransmission event

AbortionAbortion

Some farms may have bothSome farms may have both– prolonged history of sporadic prolonged history of sporadic

abortionsabortions– occasional abortion outbreaksoccasional abortion outbreaks


Cows in late gestationCows in late gestation Clinically affected live calves Clinically affected live calves

uncommonuncommon Variable deficitsVariable deficits

– limb dysfunctionlimb dysfunction mild proprioceptive deficitsmild proprioceptive deficits complete paralysiscomplete paralysis

Multifocal encephalomyelitisMultifocal encephalomyelitis– grey matter of spinal cordgrey matter of spinal cord


Cows in late gestationCows in late gestation Calves’ immune’s system Calves’ immune’s system

fully developed fully developed– calf able to fight off calf able to fight off

infectioninfection– most common result of most common result of

transplacental infectiontransplacental infection


Majority of calves infected in Majority of calves infected in utero are clinically normalutero are clinically normal

High precolostral antibody titerHigh precolostral antibody titer– 80-100% calves born to seropositive 80-100% calves born to seropositive

dams are seropositivedams are seropositive Important for maintenance of Important for maintenance of

disease within herdsdisease within herds

Reduced milk Reduced milk productionproduction

Thurmond MC, Hietala SK. Thurmond MC, Hietala SK. JAVMAJAVMA. . 1997; 210(5):672-4.1997; 210(5):672-4.

118 (+) and 254 (-) heifers118 (+) and 254 (-) heifers Seropositive heifers:Seropositive heifers:

– 2.5 lb/hd/day less milk2.5 lb/hd/day less milk– 0.14 lb/hd/day less fat0.14 lb/hd/day less fat

Other studies showOther studies show variable resultsvariable results

Decreased weight gainDecreased weight gain

>1000 weaned steers from 92 TX >1000 weaned steers from 92 TX herdsherds

Seropositive steers:Seropositive steers:– Lower postweaning ADG (0.05 kg/d)Lower postweaning ADG (0.05 kg/d)– Lower slaughter weight (7.5 kg)Lower slaughter weight (7.5 kg)– No difference in feed conversionNo difference in feed conversion

Premature cullingPremature culling

Study of 8 Canadian beef herds:Study of 8 Canadian beef herds:– Waldner CL, Janzen ED, Ribble CS. Waldner CL, Janzen ED, Ribble CS. JAVMAJAVMA

1998; 213(5):685-90.1998; 213(5):685-90.– 20-50% herd prevalence20-50% herd prevalence

Seropositive cows 1.9x risk of cullingSeropositive cows 1.9x risk of culling 2.5x risk of reproductive failure2.5x risk of reproductive failure

– abortion and stillbirthabortion and stillbirth Seropositive cows Seropositive cows

younger at culling younger at culling

Clinical presentationClinical presentation

Any system can be affectedAny system can be affected– neuro and muscular deficits predominateneuro and muscular deficits predominate

No reports of abortionNo reports of abortion– mummies, resorption, weak pups exp.mummies, resorption, weak pups exp.

Purebreds overrepresentedPurebreds overrepresented– BoxersBoxers– GreyhoundsGreyhounds– LabradorsLabradors– Golden RetrieversGolden Retrievers– Basset HoundsBasset Hounds

PuppiesPuppies

Puppies affected most frequentlyPuppies affected most frequently– onset: 3-9 weeks of ageonset: 3-9 weeks of age

Ascending paralysisAscending paralysis– pelvic limbs more affectedpelvic limbs more affected

ArthrogryposisArthrogryposis– scar formation/myositisscar formation/myositis

Intracranial manifestations Intracranial manifestations absentabsent

Older dogsOlder dogs

LMN flaccid paralysisLMN flaccid paralysis Multifocal CNS involvementMultifocal CNS involvement

– +/- polymyositis+/- polymyositis Likely reactivation of prior infectionLikely reactivation of prior infection Cutaneous neosporosis Cutaneous neosporosis

seen with seen with

immunosuppressionimmunosuppression

Clinical PresentationClinical Presentation

Sporadic disease has been seen Sporadic disease has been seen in:in:– goats and sheepgoats and sheep– horseshorses

Cats susceptible experimentallyCats susceptible experimentally Never isolated from humansNever isolated from humans

– low antibody titers low antibody titers – 2 rhesus monkeys infected2 rhesus monkeys infected

DiagnosticsDiagnostics

AbortionsAbortions– one or more aborted fetusesone or more aborted fetuses– placentaplacenta– sera from aborting damsera from aborting dam

DiagnosticsDiagnostics

Pescador, et al. Pescador, et al. Vet ParasitVet Parasit 2007; 2007; 150:159-163150:159-163

258 aborted fetuses submitted to d-258 aborted fetuses submitted to d-lablab– 21% due to 21% due to N. caninumN. caninum

Aborted fetus usually autolyzedAborted fetus usually autolyzed Serosanguinous fluid in body cavitiesSerosanguinous fluid in body cavities 2 cases – pale, white foci in lungs2 cases – pale, white foci in lungs

NeosporaNeospora abortus abortus

HistologyHistology

FOCAL ENCEPHALITISFOCAL ENCEPHALITIS– necrosis & nonsuppurative inflammationnecrosis & nonsuppurative inflammation

Scattered foci of nonsuppurative Scattered foci of nonsuppurative cellular infiltrates in brain sectionscellular infiltrates in brain sections

nonsuppurative inflammation also in:nonsuppurative inflammation also in:– heartheart– skeletal muscleskeletal muscle– liverliver– lungslungs

ImmunohistochemistryImmunohistochemistry

Effective at identifying parasitesEffective at identifying parasites– tissue cysts (bradyzoites)tissue cysts (bradyzoites)– tachyzoitestachyzoites

Most commonly in brainMost commonly in brain Can also be used in Can also be used in

mummified fetusesmummified fetuses– diminished accuracydiminished accuracy

SerologySerology

Indirect Fluorescent Antibody Test Indirect Fluorescent Antibody Test (IFAT)(IFAT)– Can be used in fetuses > 5-6 mo oldCan be used in fetuses > 5-6 mo old

Enzyme-linked Immunosorbent Enzyme-linked Immunosorbent Assay (ELISA)Assay (ELISA)

Each lab will establish cut-off Each lab will establish cut-off pointspoints– often >1:50often >1:50– CSF titers of lesser magnitudeCSF titers of lesser magnitude

SerologySerology

Used as a herd screening testUsed as a herd screening test Titers fluctuate throughout Titers fluctuate throughout

gestationgestation– do not revert to seronegative statusdo not revert to seronegative status

Most cows seropositive at time of Most cows seropositive at time of abortionabortion– individual cows may be NEGATIVEindividual cows may be NEGATIVE

DiagnosisDiagnosis

Compatible gestational ageCompatible gestational age Autolyzed fetusAutolyzed fetus Disseminated inflammatory Disseminated inflammatory

lesionslesions Presence of Presence of N. caninumN. caninum parasites parasites

(IHC)(IHC)– or serological evidenceor serological evidence

Absence of other abortifacientsAbsence of other abortifacients

Prevention – negative Prevention – negative herdsherds

Close herdClose herd Open herd - only buy Open herd - only buy

seronegative imports from herds seronegative imports from herds with excellent repro or negative with excellent repro or negative herd testsherd tests

Keep dogs away from feed areasKeep dogs away from feed areas– feral canidsferal canids

Prevention – positive Prevention – positive herdsherds

Serological testing of young stockSerological testing of young stock– pre-colostral samplespre-colostral samples– after 6 mo of ageafter 6 mo of age

Dispose of aborted fetuses and Dispose of aborted fetuses and dead animalsdead animals

Embryo transferEmbryo transfer Minimize contact with canidsMinimize contact with canids

Control strategiesControl strategies

Cull females with mid-term Cull females with mid-term abortion or stillborn calvesabortion or stillborn calves

Whole-herd test, cull seropositives, Whole-herd test, cull seropositives, replace with seronegativesreplace with seronegatives

Whole-herd test, exclude heifer Whole-herd test, exclude heifer replacements from seropositive replacements from seropositive damsdams– best cost-benefit ratiobest cost-benefit ratio

VaccinationVaccination

One licensed vaccine in U.S.One licensed vaccine in U.S.– BovilisBovilis®® NeoGuard NeoGuard

Inactivated tachyzoitesInactivated tachyzoites– $3-4/dose$3-4/dose

2 doses initially2 doses initially– 5 ml subQ in 15 ml subQ in 1stst trimester trimester– 22ndnd dose 3-4 weeks later dose 3-4 weeks later

Questionable efficacyQuestionable efficacy– herd variabilityherd variability

Vaccinates are seropositiveVaccinates are seropositive

Questions?Questions?

bovine neosporosis benjamin (bj) newcomer, dvm [email protected] february 6, 2009

Documents

bradyzoites cysts

dairy cattle

cow transmission

semensexual transmission

caninum tachyzoites

caninum dna

unsporulated oocysts

life cycledefinitive