Infectious and toxic causes of pregnancy loss Flashcards
what is a definition of abortion
after 42 days of pregnancy
disruption of normal endocrinology of pregnancy
Foetal death or stress
Factors that induce abortion
severe maternal illness - high fever, hypoxia, endotoxaemia
Placentitis - release of PGF 2alpha - foetal stress and death
Effects on the foetus depends on
organism
maternal immunity
placental pathology
time of infection (organogenesis, foetus mounts its own immune response)
what are the clinical manifestation of placental and foetal infection during the first semester
regular or irregular return to oestrous, apparent infertility, abortion
what are the clinical manifestation of placental and foetal infection during the 2nd semester
Abortion, mummification, prolonged gestation, retained placenta, prolonged inter-oestrous interval
what are the clinical manifestation of placental and foetal infection during the 3rd semester
abortion, mummification, stillbirth, weak neonate, emphysematous/autolyzed, may present as dystocia. retained placenta. foetus will be serologically positive
what are the clinical signs associated with a brucellosis infection in cows vs bulls
cows: abortion -2nd half of gestation (>5month). abortion rate may be high
bulls: orchitis, epididymitis, seminal vesiculitis
what is the pathophysiology associated with a brucellosis infection
chronic placentitis, intercotyledeonary area affected
How do you diagnose a brucellosis infection
Culture (abomasal fluid, foetal lung, placenta, milk, uterine fluid, mammary lymph nodes) & serology
How is Lepto transmitted
Contact MM or skin
what are the CS associated with a lepto infection
later term abortion or at any stage
systemic signs - innaparent =, pyrexia, haemolytic anaemia
how do you diagnose a lepto infection
Dark field microscopy, FAT. PCR (urine), serology, histopath, culture (urine)
what is the aetiology associated with campylobacter infection
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
what are the CS associated with a campylobacter infection
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
How do diagnose C.foetus infection
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
what are the control startegies for herds affected with C . foetus
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
Treatment strategies for C.foetus vs T.foetus
T.foetus - no approved therapy, cull
C.foetus - oxytetracycline
Explain the control used for campylobacter
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
What is the history and clinical signs associated with listeriosis
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
How do you diagnose a listeriosis infection
pinpoint white to yellow foci may be present in the liver
culture, gram stain
immunohistochemistry
what are the causes of an infection with Bovine herpes -1
abortion, temporary infertility, respiratory disease, genital disease (infectious pustular vulvovaginaitis) entritis, encephalitis and systemic infection in calves
how is bovine herpesvirus 1 transmitted
Direct contact with upper respiratory, conjunctival or genital mucous membranes
How is bovine viral diarrhoea transmitted
inhalation, ingestion, transplacental, venreal
The reproduction effects of an infection with BVDV depend on
- stage of gestation infected
2. viral strain
what are the reproductive outcomes of an infection with BVDV
Reduced conception and pregnancy rates
abortion
developmental defects
Immunotolerance with establishment of persistent infection
what are some of the signs that can be indicative that BVDV is contributing to reduced productivity
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
what test can be performed on a foetus for BVDV
Detection of viral antigen
Detection of AB
presence of the virus may not necessarily mean that BVDV was the cause of the abortion
How do you test for a PI in a herd
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
How many samples should you take when testing for a PI in a herd
8 to 12 animals from various age groups or about 5% of the larger groups
How do you control and manage BVDV outbreaks
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
How is bluetongue virus spread
via bites from culicoides spp which obtain virus from infected sheep or cattle or contaminated semen
How does a disease of akabane virus occur
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
What are the main clinical signs associated with akabane virus infection
Abroyion, stillbirths, or neonates with skeletal deformities
76 -104 days hydroencephaly
105-174 - arthogryposis
mid term abortion
How does the infection with neospora canium occur in cattle
Ingestion of oocyst in dog faeces, contaminated feed or water
Vertica; (congenital txm) major route in cattle
What are the clinical findings in a dam that has been infected with n.canium
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
what are the clinical signs seen in neonatal calves that are infected with n.canium
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
How do you diagnose an infection with neospora canium
histopathology
serology
indirect FAT, ELISA, on foetalfluid
PCR - ag
what control measures can be put in place to manage N. canium infection
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
