Infectious and toxic causes of pregnancy loss Flashcards

1
Q

what is a definition of abortion

A

after 42 days of pregnancy
disruption of normal endocrinology of pregnancy
Foetal death or stress

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2
Q

Factors that induce abortion

A

severe maternal illness - high fever, hypoxia, endotoxaemia

Placentitis - release of PGF 2alpha - foetal stress and death

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3
Q

Effects on the foetus depends on

A

organism
maternal immunity
placental pathology
time of infection (organogenesis, foetus mounts its own immune response)

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4
Q

what are the clinical manifestation of placental and foetal infection during the first semester

A

regular or irregular return to oestrous, apparent infertility, abortion

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5
Q

what are the clinical manifestation of placental and foetal infection during the 2nd semester

A

Abortion, mummification, prolonged gestation, retained placenta, prolonged inter-oestrous interval

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6
Q

what are the clinical manifestation of placental and foetal infection during the 3rd semester

A

abortion, mummification, stillbirth, weak neonate, emphysematous/autolyzed, may present as dystocia. retained placenta. foetus will be serologically positive

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7
Q

what are the clinical signs associated with a brucellosis infection in cows vs bulls

A

cows: abortion -2nd half of gestation (>5month). abortion rate may be high
bulls: orchitis, epididymitis, seminal vesiculitis

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8
Q

what is the pathophysiology associated with a brucellosis infection

A

chronic placentitis, intercotyledeonary area affected

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9
Q

How do you diagnose a brucellosis infection

A

Culture (abomasal fluid, foetal lung, placenta, milk, uterine fluid, mammary lymph nodes) & serology

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10
Q

How is Lepto transmitted

A

Contact MM or skin

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11
Q

what are the CS associated with a lepto infection

A

later term abortion or at any stage

systemic signs - innaparent =, pyrexia, haemolytic anaemia

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12
Q

how do you diagnose a lepto infection

A

Dark field microscopy, FAT. PCR (urine), serology, histopath, culture (urine)

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13
Q

what is the aetiology associated with campylobacter infection

A

males are asymptomatic carriers
females: immune following infection but not permanent (<15months)
txm: veneral, contaminated semen, AI equipment
==> cannot get into your herd without the introduction of new animals - usually originated from bringing in new animals

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14
Q

what are the CS associated with a campylobacter infection

A

history of exposure to outside bulls or cows
increased calving to conception intervals
long inter-oestrous intervals, greater variability in calf age
irregular return intervals to oestrous
greater no of cows not preg than expected at herd preg testing
post coital pyometra
C.foetus: infertility from early embryonic death is the most frequent clinical manifestation, occ abortion

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15
Q

How do diagnose C.foetus infection

A

History - to the introduction of new animals
isolate organism: preputial wash (FAT)
PCR - 3 test, 1 weeks apart neede for high sensitivity and specificity
vaginal mucous
aborted foetal smaples
Virgin heifer test mating

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16
Q

what are the control startegies for herds affected with C . foetus

A

immunity; develops within 3 to 6 months
Bulls: test and cull, avoid borrowing bulls , + herd contact with strays bulls and cows, purchase only young virgin bulls
restrictive breeding to bulls

vaccination
C.fetus - effective
Maintain a closed herd
AI: use AI rather than natural breeding

17
Q

Treatment strategies for C.foetus vs T.foetus

A

T.foetus - no approved therapy, cull

C.foetus - oxytetracycline

18
Q

Explain the control used for campylobacter

A

New bulls vaccinate twice, six weeks apart before coming into contact with females. Two vaccination will clear the disease from most infected bulls, all bulls should be given an annual boosters vaccination
Vaccinate all heifers prior to joint
- if <18months old at joining, two doses (5ml) four to sex weeks apart
- over 18 month only require one dose

19
Q

What is the history and clinical signs associated with listeriosis

A

sporadic with occasional abortion storms
aborting cows may be asymptomatic or show no signs of illness, fever, due to metritis
can be associated with teh consumption of poor quality silage
Abortion usually in the 3rd semester

20
Q

How do you diagnose a listeriosis infection

A

pinpoint white to yellow foci may be present in the liver
culture, gram stain
immunohistochemistry

21
Q

what are the causes of an infection with Bovine herpes -1

A

abortion, temporary infertility, respiratory disease, genital disease (infectious pustular vulvovaginaitis) entritis, encephalitis and systemic infection in calves

22
Q

how is bovine herpesvirus 1 transmitted

A

Direct contact with upper respiratory, conjunctival or genital mucous membranes

23
Q

How is bovine viral diarrhoea transmitted

A

inhalation, ingestion, transplacental, venreal

24
Q

The reproduction effects of an infection with BVDV depend on

A
  1. stage of gestation infected

2. viral strain

25
Q

what are the reproductive outcomes of an infection with BVDV

A

Reduced conception and pregnancy rates
abortion
developmental defects
Immunotolerance with establishment of persistent infection

26
Q

what are some of the signs that can be indicative that BVDV is contributing to reduced productivity

A

Reduced reproductive performance
Increased calf morbidity and mortality
Reduced weaner/yearling growth rates and health
Mucosal disease - animal has no cytopathic form gets infected w/ cytopathic form
increased incidence of respiratory disease

27
Q

what test can be performed on a foetus for BVDV

A

Detection of viral antigen
Detection of AB
presence of the virus may not necessarily mean that BVDV was the cause of the abortion

28
Q

How do you test for a PI in a herd

A

ear notch testing; Antigen capture ELISA
PCR test
Virus isolation immunochemistry on tissue smaoles
Not that if a test if positive you may need to test again in a couple of weeks to rule out the presence of a transient infection in a non-PI animal

29
Q

How many samples should you take when testing for a PI in a herd

A

8 to 12 animals from various age groups or about 5% of the larger groups

30
Q

How do you control and manage BVDV outbreaks

A

Biosecurity - minimise the risk of introduction, minimise virus transmison within a herd, Minimise BVDV transfer through fomites, minimise risk of introducing virus via artificial breeding technology

31
Q

How is bluetongue virus spread

A

via bites from culicoides spp which obtain virus from infected sheep or cattle or contaminated semen

32
Q

How does a disease of akabane virus occur

A

movement of naive cattle at a susceptible stage of pregnancy to an endemic area
Movement of vectors to areas where cattle are naive
prolonged drought then by suitable wet condtion - leaves a proportion of pop suddenly exposed to vector

33
Q

What are the main clinical signs associated with akabane virus infection

A

Abroyion, stillbirths, or neonates with skeletal deformities
76 -104 days hydroencephaly
105-174 - arthogryposis
mid term abortion

34
Q

How does the infection with neospora canium occur in cattle

A

Ingestion of oocyst in dog faeces, contaminated feed or water
Vertica; (congenital txm) major route in cattle

35
Q

What are the clinical findings in a dam that has been infected with n.canium

A

abortion throught gestation but most often during 2nd trimester
aborted, mummified, still born foetuses, low birth weight or weak calves
abort again in subsequent pregnancy

36
Q

what are the clinical signs seen in neonatal calves that are infected with n.canium

A

up to 95% clinically normal
clinical signs are not apparent in calves older than 2 months - difficult rising, undernourishd, early neonatal loss, general signs associated with the neurological system

37
Q

How do you diagnose an infection with neospora canium

A

histopathology
serology
indirect FAT, ELISA, on foetalfluid
PCR - ag

38
Q

what control measures can be put in place to manage N. canium infection

A

Serological testing of calves at 6months to eliminate those congenitally or postnatally infected
control of dogs - prevent contamintion of stock
disposal of carcases
test and culling infected cows
breeding replacemnt only from seronegative cows