Infectious and toxic causes of pregnancy loss

Question 1

what is a definition of abortion

Answer 1

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

Question 2

Factors that induce abortion

Answer 2

severe maternal illness - high fever, hypoxia, endotoxaemia

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

Question 3

Effects on the foetus depends on

Answer 3

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

Question 4

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

Answer 4

regular or irregular return to oestrous, apparent infertility, abortion

Question 5

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

Answer 5

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

Question 6

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

Answer 6

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

Question 7

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

Answer 7

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

Question 8

what is the pathophysiology associated with a brucellosis infection

Answer 8

chronic placentitis, intercotyledeonary area affected

Question 9

How do you diagnose a brucellosis infection

Answer 9

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

Question 10

How is Lepto transmitted

Answer 10

Contact MM or skin

Question 11

what are the CS associated with a lepto infection

Answer 11

later term abortion or at any stage

systemic signs - innaparent =, pyrexia, haemolytic anaemia

Question 12

how do you diagnose a lepto infection

Answer 12

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

Question 13

what is the aetiology associated with campylobacter infection

Answer 13

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

Question 14

what are the CS associated with a campylobacter infection

Answer 14

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

Question 15

How do diagnose C.foetus infection

Answer 15

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

Question 16

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

Answer 16

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

Question 17

Treatment strategies for C.foetus vs T.foetus

Answer 17

T.foetus - no approved therapy, cull

C.foetus - oxytetracycline

Question 18

Explain the control used for campylobacter

Answer 18

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

Question 19

What is the history and clinical signs associated with listeriosis

Answer 19

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

Question 20

How do you diagnose a listeriosis infection

Answer 20

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

Question 21

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

Answer 21

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

Question 22

how is bovine herpesvirus 1 transmitted

Answer 22

Direct contact with upper respiratory, conjunctival or genital mucous membranes

Question 23

How is bovine viral diarrhoea transmitted

Answer 23

inhalation, ingestion, transplacental, venreal

Question 24

The reproduction effects of an infection with BVDV depend on

Answer 24

1. stage of gestation infected

2. viral strain

Question 25

what are the reproductive outcomes of an infection with BVDV

Answer 25

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

Question 26

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

Answer 26

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

Question 27

what test can be performed on a foetus for BVDV

Answer 27

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

Question 28

How do you test for a PI in a herd

Answer 28

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

Question 29

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

Answer 29

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

Question 30

How do you control and manage BVDV outbreaks

Answer 30

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

Question 31

How is bluetongue virus spread

Answer 31

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

Question 32

How does a disease of akabane virus occur

Answer 32

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

Question 33

What are the main clinical signs associated with akabane virus infection

Answer 33

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

Question 34

How does the infection with neospora canium occur in cattle

Answer 34

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

Question 35

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

Answer 35

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

Question 36

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

Answer 36

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

Question 37

How do you diagnose an infection with neospora canium

Answer 37

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

Question 38

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

Answer 38

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