Farm animal abortion Flashcards

Question

Infectious causes in cattle - sporadic causes

Answer 1

▪ Trueperella pyogenes ▪ E. coli (ZOONOTIC POTENTIAL) ▪ Histophilus somni ▪ TB (NOTIFIABLE & ZOONOTIC POTENTIAL)

Answer 2

▪ Border disease ▪ Bluetongue virus (NOTIFIABLE) ▪ Schmallenberg virus

Answer 3

▪ Chlamydophila abortus ▪ Campylobacter fetus fetus, Campylobacter jejuni ▪ Listeria spp. ▪ Salmonellosis ▪ Leptospirosis ▪ Brucellosis (NOTIFIABLE) ▪ Coxiella burnetti (Q Fever) – Rickettsia ▪ Tick Borne Fever - Anaplasma phagocytophilum ^ all bar tick borne fever have zoonotic potential

Answer 4

- Toxoplasma gondii (ZOONOTIC POTENTIAL)

Answer 5

▪ *Placenta – cotyledon and surrounding membrane* -- Detect fungi, C. abortus, C. burnetti, Brucella abortus -- Toxoplasma PCR ▪ Foetal stomach contents -- Bacteriology – aseptic -- Direct culture and selective culture (Salmonella, Campylobacter, Brucella) ▪ Foetal fluid -- ‘Plain’ tube – serology -- BVD Ab/Ag, BDV Ab, Neospora Ab, Leptospirosis Ab, SBV Ab ▪ Lung -- can be used for culture ▪ Spleen -- BVD or BDV PCR ▪ Liver -- BoHV-1 -- Trace mineral analysis ▪ Thyroid -- Iodine ▪ Hindbrain -- SBV PCR

Answer 6

▪ Placenta ▪ Brain ▪ Lung ▪ Trachea ▪ Liver ▪ Spleen ▪ Kidney ▪ Thyroid ▪ Heart

Answer 7

▪ Cattle serology -- BVDV (and PCR) -- Lepto -- Neospora -- IBR -- SBV ▪ Ovine serology -- EAE -- Toxoplasma -- Border disease (and PCR) -- SBV

Answer 8

▪ Protozoal parasite ▪ Canines are the definitive host but vertical transmission much more common

Answer 9

Exogenous transmission - Canine ingestion of tissue cysts e.g. in placenta → oocysts passed in faeces →contaminate feed/water →sporozoites in the intestinal tract →tachyzoites in neural tissue, macrophages, hepatic cells, placenta, and others → bradyzoites primarily in neural tissue ▪ Vertical transmission from tachyzoites, via the placenta → foetus Endogenous transmission - Previously/persistently infected cow has reactivation of tissue cysts

Answer 10

▪ Abortion typically at 4-7 months but can cause resorptions, mummification, stillbirth, or may be born alive and persistently infected +/- congenital CNS disease ▪ Persistently infected calves grow to become persistently infected cows → 40-50% abort in their first year, or results in vertical transmission

Answer 11

▪ Serology in cows -- Negative – rules out Neospora -- Positive – not diagnostic as not definitely the cause -> If positive, statistically they are 6-7 times more likely to abort than those that are not -> Antibody levels tend to be highest 10 to 4 weeks before calving ▪ PCR on foetal brain ▪ Histopathology +/- IHC on fixed brain

Answer 12

▪ Infected dog faeces ▪ Remove access to placental material ▪ Test purchased cattle ▪ Avoid retaining breeding heifers born from seropositive cows ▪ Test and cull cows

Answer 13

▪ Pestivirus – BVDV-1 and BVDV-2 (BVDV-2 only really in the USA) ▪ Cytopathic and non-cytopathic strains

Answer 14

Infected cow → infected foetus ▪ Abortion can occur at any point in gestation (usually 1st/2nd trimester) ▪ 0-30 days – infertility or early embryonic death ▪ 18-125 days – PI calves ▪ 80-150 days – congenital defects e.g. cerebellar hypoplasia, cataracts, hydrocephalus etc. ▪ >150 days – the calf can launch an immune response and often survives

Answer 15

= non-PI cow carrying a PI calf ▪ Cow is antibody negative

Answer 16

- lack of characteristic PM lesions ▪ PCR, antigen and antibody testing available ▪ PI calf – antigen positive, antibody negative ▪ PCR on aborted calf tissue (spleen often used) ▪ Antigen or antibody testing on blood (avoid antibody testing on post-colostral neonatal calves) ▪ Antigen/PCR testing on tissue in live animals e.g. ear tag

Answer 17

- routine herd testing - culling PIs - vaccination

Answer 18

- Leptospira borgpetersenii serovar Hardjo - Leptospira interrogans serovar Hardjo

Answer 19

- infertility - abortion usually >6m - premature calves - milk drop

Answer 20

▪ Vaccination ▪ Antibiotics – streptomycin, dihydrostreptomycin, oxytetracycline, amoxicillin ▪ Avoid grazing with sheep

Answer 21

▪ usually no gross PM lesions ▪ PCR on foetal kidney, lung, or placenta ▪ Histopathology – foetal interstitial nephritis is pathognomonic ▪ Maternal serology – can be difficult to interpret -- Titres are often in decline by the time of abortion as abortion often occurs weeks to months after maternal infection -- Better used as a screening tool for the presence of lepto in the herd

Answer 22

▪ PrimarilyS.Dublin- ~80%

Answer 23

▪ Sporadic cause of abortion +/- dysentery and pyrexia in cows

Answer 24

- introduction of carrier animals or contamination of feed/water

Answer 25

- culture from foetal stomach contents ▪ Serology may be useful, but titres fall rapidly after abortions ▪ Faecal culture from the dam has low sensitivity ▪ Cows that abort shed for a very short period of time compared to enteric cases where there is intermittent or continuous shedding

Answer 26

- vaccination - destroy contaminated bedding - isolate cows until vaginal discharge stops

Answer 27

▪ Multiple strains - all, except S. abortusovis, are zoonotic

Answer 28

▪ Ewes may be ill e.g. scour, metritis ▪ S. abortusovis -- few clinical signs other than abortion in the last 6 weeks of gestation -- Lambs may be born alive but die within the first week of life ▪ S. montevideo -- few clinical signs other than abortion -- no diarrhoea in lambs ▪ S. typhimurium -- pyrexia, anorexia -- profuse scour in ewes with foul smelling vaginal discharge -- May be fatal -- Lambs not aborted may be born stillbirth, or born alive and die soon after with evidence of scour -- Outbreaks often follow times of stress ▪ S. Dublin -- clinical signs similar to S. typhimurium but usually not as severe

Answer 29

- culture of foetal stomach contents

Answer 30

- treat ewes with a sensitive antibiotic if necessary

Answer 31

- vaccination - isolate aborted ewes - avoid stress

Answer 32

- Campylobacter fetus subsp. venerealis - Campylobacter fetus subsp. fetus Both ^ cause abortions in cattle around 4-8m of gestation

Answer 33

▪ Cause of infertility and embryonic death primarily, associated with a mucopurulent endometritis ▪ Occasionally abortion at 4-8 months ▪ Venereal transmission ▪ Cows – fertility returns after 4-8 months once the uterus recovers ▪ Bulls – may recover or be infected for life. The older the bull, the more likely to be persistently infected

Answer 34

▪ Culture from vaginal washes or preputial scrapings/washes – difficult to culture successfully ▪ Vaginal Mucous Agglutination Test – picks up ~50% of positive cows ▪ Serology – very poor humoral response to venereal infection so of little value

Answer 35

▪ Found in the intestinal tract → faeco-oral transmission ▪ Placental lesions – necrosis, intercotyledonary thickening and oedema, yellow-brown cotyledons ▪ Placental culture is difficult due to other contaminants overgrowing -- Foetal stomach contents – Campylobacter enrichment cultures

Answer 36

▪ Campylobacter fetus fetus – from carrier sheep ▪ C. jejuni from wildlife vectors ▪ Faeco-oral transmission → ewe to ewe transmission

Answer 37

▪ infection→abortion 7-25 days later, followed by strong immunity ▪ Abortion in the last 6 weeks of gestation and weak lambs born alive. ▪ May see diarrhoea as well as abortions. ▪ Up to 25% of ewes may abort in naïve flocks. ▪ Very few clinical signs in ewes other than abortion initially, though metritis may develop ▪ Aborted material is infectious ▪ Venereal spread not a feature (as in cattle – Campylobacter fetus venerealis) ▪ Can see waves of disease every 4-5 years as immunity wanes in individuals and through addition of naïve animals to the flock.

Answer 38

▪ Placenta may have intercotyledonary oedema and cotyledonary necrosis ▪ Foetal livers may have multifocal areas of grey necrotic foci – pathognomonic ▪ Culture – foetal stomach contents (or placenta, or liver) ▪ Serology – not useful

Answer 39

▪ Antibiotics generally not effective ▪ Vaccines not licensed in the UK; serotype distributions in NZ are different to UK ▪ Some people will mix aborted ewes with lambed ewes to generate immunity

Answer 40

▪ Protozoal parasite – infection is through ingestion of oocysts shed in cat faeces ▪ Zoonotic ▪ Cats are definitive host – sheep (and other mammals) are intermediate hosts -- Oocysts may survive for up to 2 years on pasture, feed, or bedding -- Up to 1 million oocysts per gram of cat faeces; as few as 200 needed to infect a ewe

Answer 41

▪ Infection in non-pregnant sheep is usually asymptomatic but results in immunity. ▪ Ewes remain persistently infected for life but are immune so unlikely to abort again. ▪ Causes infertility, mummification, stillbirth and abortion depending on stage of gestation and infective dose. ▪ <60 days → foetal resorption → high barren rate if ram has been removed ▪ Mid-gestation → abortion or mummification ▪ >120 days → stillbirth, weak lambs, or normal lambs

Answer 42

– ‘frosted strawberry’ cotyledons ▪ Intercotyledonary areas unaffected (c.f. C. abortus) ▪ PCR – placenta ▪ Foetal serology – foetal fluid ▪ Maternal serology – antibodies can remain elevated for years (paired?)

Answer 43

- retain aborted ewes - keep old neutered cats on farm - vaccinate

Answer 44

* Gram negative intracellular bacteria * >80% of outbreaks are from the purchase of infected ewes * Bacteria are present in aborted material and venereal fluids, and can survive for weeks

Answer 45

* Ewes infected early in pregnancy may abort this year. If non-pregnant or in late gestation (~>100d), they lie dormant until the next pregnancy. * Results in late-term placentitis and abortion typically in the last 3 weeks of gestation. * Some ewes become carriers and may excrete organism in their faeces.

Answer 46

▪ Ewes are not ill ▪ Intercotyledonary areas are thickened, leathery, and oedematous ▪ Necrosis of foetal cotyledons ▪ May get birth of weak lambs ▪ Smears from intercotyledonary areas are stained with a modified ZN stain → intracellular cocci seen ▪ Serology – maternal or foetal fluids

Answer 47

- retain ewes - biosecurity - vaccinate - antibiosis?

Answer 48

* Oxytetracycline can help maintain the placenta in infected ewes to allow lambs to be born alive * Must be given after 90 days (when the placenta starts to deteriorate) and before day 126 (3 weeks before lambing) * If there are ewes 6-8 weeks off lambing (day 91-105) a dead vaccine (Inmeva) could be used. (Inmeva not recommended during last month of gestation) * If <3 weeks from lambing, they may pick up C. abortus this year and abort next year. * Can give live vaccine pre-tupping next year (will reduce abortions by ~50% in ‘pre-programmed’ ewes, but not prevent), or use antibiotics at day 91-126 in next gestation. * Once a fully implemented vaccination protocol is in place antibiotics shouldn’t be required

Answer 49

▪ Isolate ewe (not required for toxo but a sensible precaution) ▪ Dispose of (if not being sampled) aborted material ▪ Treat systemic disease e.g. Salmonellosis ▪ Don’t foster on lambs (esp. ewe lambs that may be kept as replacements) to affected ewes (EAE risk) ▪ Mark ewes so that they can be identified for serology at a later date if required. ▪ Maintain good hygiene and biosecurity. ▪ Take disease specific actions e.g. prevent feed access for wild birds with C. jejuni ▪ Highlight zoonotic risk to farmer

Answer 50

▪ EAE – purchase accredited disease-free stock and keep separate until after first lambing ▪ Toxo – prevent transmission via the definitive host, i.e. keep cats out of feed stores. ▪ Vaccinate – EAE, Toxoplasmosis, Campylobacter (import), Salmonella abortusovis 29

Answer 51

Enzovax (MSD) - live attenuated - indications -- replacements >5m/o -- recommended to vaccinate between 4m and 1m before tupping -- many be administered with Toxovax at different sites - duration: at least 3y Cevac Chlamydia (Ceva): - live attuenated - indications -- replacements >5m/o -- recommended to vaccinate between 4m and 1m before tupping -- many be administered with Toxovax at different sites - duration: not stated Inmeva (Hip): - inactivated - indications: -- 2 doses, 3w apart, the 1st at least 5w before tupping -- can be used during pregnancy -- not recommended in the last month of pregnancy - duration: annual booster 2w before mating required Toxovax (MSD) - live tachyzoites - indications: -- replacements >5m/o -- should be vaccinated in the period from 4m to 3w prior to tupping -- may be given with live attenuated EAE vaccine at different sites - duration: at least 2y Live EAE or Toxo vaccine should not be used by women of childbearing age or immunocompromised individuals.

Answer 52

* An orthobunyavirus – spread mainly by culicoides midges affecting cattle and sheep

Answer 53

▪ May see pyrexia, diarrhoea, anorexia, milk drop ▪ Abortion and stillbirth, with congenital defects -- Arthrogryposis most common defect -- Neurological defects – hydrancephaly, hydrocephalus, cerebellar hypoplasia, porencephaly -> Think BTV.

Answer 54

- limb defects are indicative ▪ Confirmation by PCR on brain ▪ Serology – maternal or foetal

Answer 55

▪ Difficult – fly repellents or altering breeding season to avoid vectors ▪ Dams develop long-lasting immunity

Answer 56

- due to stress and PG release

Answer 57

- Neospora caninum

Answer 58

- through discharge, placental material

Answer 59

- remove brain for sampling and big hydrocephalus or fluid filled cavity - have statutory requirement to notify APHA for potential testing for bluetongue as also causes these

Farm animal abortion Flashcards

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