Viral infections of the genital tract Flashcards
Where do viruses often spread to the genital tract haematogenously or ascendingly from?
upper respiratory tract
Broadly, how may viruses cause reproductive failure? 4
Viral replication in foetal tissues leading to malformation or death.
Damage to placental BVs —> interrupted blood supply to foetus
Stress and pyrexia due to viral infection
Combination of above
What does EHV-1 cause? 4
Abortions (last 3rd pregnancy), accompanies or shortly follows foetal death
respiratory disease - lung oedema
paralysis
Multifocal necrosis - liver, lungs, spleen
What does EHV-3 cause? 2
genital pustules (exanthema, more externally visible) but not abortion, hyperplastic lymphoid nodules, usually a transient virus
What does EHV-4 cause?
respiratory disease, very rarely isolated abortions
What are the 2 main viruses affecting horse genital tracts?
EHV
EAV = Equine Arteritis Virus - NOTIFIABLE - last case 2012
How to diagnose EHV-1 abortion.
PME - foetus and placenta
PCR or virus isolation
Microscopic examination of tissue sections - EHV-1 immunostaining
What is a sign of interpartum death?
meconium around the anus
How can EHV be prevented?
Isolate pregnant mares in last trimester
Vaccinate all horses on premises - combination vaccines (EHV-1 and 4)
How can EHV be controlled?
Isolate mare in case of abortion
Collect foetus and placenta - Ag test
Paired serum samples (mare) - test for rising Ab titre but difficult in cases of vaccination and/or recrudescence due to stress of abortion)
How does EAV enter the horse? 2
respiratory tract or semen
What does EAV infect? 2
macrophages and endothelial cells and causes arteritis
How do you diagnose EAV? 4
CLINICAL SIGNS - variable, fever, depression, conjunctivitis/pink eye, abortion, BUT may be subclinical
PME - foetus and placenta for PCR
PAIRED SERUM - mare, virus neutralising Ab titres
TRAVEL HISTORY?
How are stallions affected by EAV?
persistently infected, shed virus in semen without clinical signs.
The virus persists in the accessory glands. Does not persisit in the mare.
When is EAV notifiable?
If clinical signs are observed in a stallion or evidence for EAV infection is present by semen or blood testing.
Clinical signs or laboratory results indicate EVA in a mare mated or AI’d within past 14 days.
How can EAV be controlled? 3
PME - foetus or semen - virus isolation or PCR
Movement restrictions
Stallion vaccination (confirm Ab negative prior to doing this)
What is the equivalent of BVDV in sheep?
Border disease virus/ Hairy shaker lambs
How is BVDV shed? 3
respiratory secretions, (faeces, semen)
Where does BVDV replicate?
respiratory and enteric tract
haematogenous spread to foeuts via placenta
Outline the different phases of BVDV infection
FIRST TRIMESTER (0-110): no foetal immunocompetenece, embryonic/foetal death –> resportion, abortion, mummification, PI calf/Hairy shaker lamb
SECOND TRIMESTER (111-190): abortions mummification, PIs usually only until day 140, congenital deformities (especially days 125-175) - e.g. cerebellar hypoplasia
THIRD TRIMESTER (after day 191): occsasional abortions/stillbirths/ weak calves, predominantly ‘normal’ calves
How can BVD be diagnosed? 4
PME - foetus, PCR of lymphoid tissue
Histopathology + immunohistochemistry (esp brain tissue)
Foetal serology - free foetal fluids, indicates exposure
Maternal serology - difficult to interpret sometimes.
How can BVDV be prevented/controlled?
Vaccinate dams before pregnancy
Identify and removed PI animals (Ag test + second Ag test or Ab test)
Various EU coutries have eradication programs
What can BHV-1 cause? 2
IBR
IPV or IBP
How can BHV be spread? 3
venereal, contact or aerosol
Outline the features of IPV/IBP infections
similar appearance to equine coital exanthema (ECE) painful genital lesions swelling frequent urination tend to be self-limiting
What happens in BHV-1 abortions?
Follows respiratory infections mostly May occur weeks after infection of dam Usually 4-8 months gestation Necrosis in foetal liver and lung Frequently extensive autolysis (calf) As a cause of abortion, this is uncommon in the UK but more common in the US.
How can BHV-1 be diagnosed? 2
Immunofluorescence/immuno-peroxidase on foetal tissues (e.g. FAT liver tissue)
Serology - difficult to intrepret (recrudescence - cause or consequence of abortion?)
How can BHV-1 be prevented/controlled
Isolate and test new stock
Vaccination - reduces duration and severity of clinical disease but doesn’t prevent infection.
Eradication programs - various EU countries
What type of virus is SBV?
orthobunyavirus
Arbovirus (Culicoides spp)
Clinical signs - SBV - 3
arthrogryposis Hydrancephaly cerebellar/cerebral hypoplasia Scoliosis Brachygnathis
How can SBV be diagnosed?
PCR (brain tissue)
Histopathology
Foetal serology
Maternal serology
Define PRRS
Porcine reproductive and respiratory syndrome
What viruses can affect pig reproductive tracts? Which is the most important? 5
PRRS (most important) Porcine parvovirus Influenza Porcine circovirus Swine Herpesvirus - 1
How is a pig infected with PRRS?
Respiratory tract: aerosol
Genital tract: infected semen
What clinical signs can PRRS cause?
Respiratory disease, oedema, subclinical
‘Blue ear diesease’
Immunosuppression (like BVDV)
Late abortions/mummifications/premature piglets (arteritis of umbilical vessels in foetus)
How can PRRS abortions be diagnosed?
PCR - lymphoid tissue
How can PRRS be prevented/controlled?
SPR, all in all out, quarantine new stock
Separate pregnant sows from rest of herd
Avoid transfer of fomites
Screen semen for AI (PCR)
Vaccination - reduces clinical signs, inactivated
DIFFICULT: because PRRS rapidly mutates.
What syndrome does porcine parvovirus cause?
SMEDI = stillbirths, mummification, embryonic death and infertility
Early embryonic death ( resorption, infertility
Later stage infection –> foetal death and mummification
Late stage infection –> stillbirths
If infected >70 days, foetal death less frequent due to immune response.
Abortion uncommon
How does porcine parvovirus spread?
faecal oral
transplacental - foetus has rapidly dividing cells
How can porcine parvovirus be diagnosed? 3
PCR - liver, (heart), if CRL is t always work, viable virus and fresh tissue needed.
How can porcine parvovirus be prevented/controlled?
vaccination
What is swine influenza?
typa A influenza virus (H1N1, H3N2) Predominately respiratory signs Pyrexia >41 degrees Abortions in sows Transplacental infections rare
How is swine influenza diagnosed?
PCR/(virus isolation) - acutely infected animals
Paired serology
What have porcine circovirus 2 (pCV2) been associated with? 8
abortions, mummifications, stillbirths but not confirmed in UK
Weak piglets, congenital tremor - not confirmed in UK
PMWS
PDNS
PCV-2 associated disease
What does PMWS stand for?
post-weaning multisystemic wasting syndrome
What does PDNS stand for?
porcine dermatitis and nephropathy syndrome
How can pCV-2 be diagnosed?
Histopathology (heart), IHC - not PCR
How can pCV2 be managed?
SPF
all-in-all-out
optimised management conditions
vaccination
What is another word for Aujeszky’s disease?
pseudorabies
Outline the features of Aukesky’s disease /pseudorabies in pigs.
Herpesviridae (family) NOTIFIABLE Enters via respiratory tract CNS signs and high mortality in piglets In pregnant sows: haematogenous spread to foetus --> abortions/stillbirth Eradicated from UK Mass mortality Dogs are really susceptible to this disease
What are the features of Classical Swine Fever?
Pestivirus in family Flaviviridae
NOTIFIABLE (last outbreak 2000)
High mortality
Diarrhoea
Haemorrhages - skin and other organs (kidney)
Abortion, mummification, stillbirths, congenital tremors
What are the features of AFRICAN swine fever?
Family = Asfarviridae
NOTIFIABLE
So far never occurred in UK
Clinical signs very similar to classical swine fever including reproductive failure
What viruses can affect the reproductive tract of DOGS?
Canine herpesvirus (CHV)
What viruses can cause reproductive failure in cats? 2
Feline leukaemia virus Feline parvovirus (feline panleukopaenia virus)
What is th e’fading puppy syndrome’?
Describes puppies with CHV. They are infected during birth or shortly after and develop systemic herpesvirus infection. Puppies seem healthy, then squeal, then die. Immature immune system but particularly poor regulation of body temperature allows infection to establish.
Organ necrosis + death. Haemorrhages (kidney).
Dx = gross and histopathological findings (intranuclear inclusion bodies)
Vaccine now available for pregnant bitches
Outline FLV
Can cross placenta and lead to reproductive failure (resorption of foetuses or abortion).
Dx = Ag test (queen) or immunofluorescence/PCR on aborted foetuses
Prevention = vaccination
How does feline parvovirus/ feline panleukopaenia virus affect the reprodutive tract?
Can lead to reproductive failure (esp early) or cerebellar hypoplasia (esp later)
Prevention = vaccination
How can viruses be detected (generally)? 2
Samples - foetal organs, whole foetus, placenta
Virus isolation, PCR or Ag detection
What are the problems associated with virus diagnosis?
If samples aren’t fresh:
viruses lose infectivity
nucleic acids and proteins degrade
How can antibodies against viruses be detected?
In foetal fluids (only useful once foetus is immunocompetent)
Serology - dam, shows rising Ab titres
What are the problems associated with detecting antibodies against virus infections?
Possible delay between:
infection of dam and foetus
infection of foetus and reproductive failure being apparent (seroconversion
