Viruses of the Genital Tract Flashcards
How are viruses transferred? Give examples of each
Horizontal - venereal (lesions in genital tract) or spread from other sites (haematogenous/ascending)
Vertical - from mother to offspring (placenta, genital tract or milk)
What may cause reproductive failure if infected with a virus?
Viral replication in foetus leading to malformation or death - Damage to placental blood vessels - Stress and pyrexia due to viral infection
What is a carrier animal?
An animal which sheds the virus but shows no obvious clinical signs
What ways can a carrier animal pass viral infection?
Semen - Respiratory secretions - Faeces
What viruses affect the reproductive system of a horse?
Equine herpesvirus (EHV) - Equine arteritis virus (EAV)
What types of EHV are there? Which will cause abortion?
EHV-1 (causes abortion) - EHV-3 - EHV-4 (sometimes causes abortion)
When a mare is infected with EHV-1 when would you expect the abortion to occur? What other signs are there of it being EHV-1?
Last third of pregnancy - Lung oedema and multifocal necrosis in liver, lungs and spleen
In the case of an abortion with a mare what procedures should be carried out?
Isolate affected mare - Collect foetus and placenta for antigen testing - Serum samples in mare for antibody titre
How would you prevent EHV in mares?
Isolate pregnant mares in last trimester - Vaccination of all animals on premises (EHV-1 and EHV-4)
What does EAV stand for?
Equine Arteritis Virus
How does EAV enter the mare?
Via respiratory tract or semen of infected stallion
Where does EAV infect and what does it cause?
Macrophages and endothelial cells - Arteritis
Why might it be difficult to diagnose EAV?
Can be subclinical - Stallions shed persistently/intermittently - Virus persists in accessory glands - Doesn’t persist in mare
What makes EAV a notifiable disease?
Clinical signs observed in stallion or found by investigation - Clinical signs in mated mare or laboratory tests indicate EAV
When vaccinating stallions what do you have to confirm?
Confirm that the stallion is antibody negative before vaccination
What viruses infect the reproductive tract of cattle?
Bovine Viral Diarrhoea Virus (BVDV) - Bovine herpesviruses - Schmallenberg virus - Bluetongue virus
What causes BVDV? How is it transmitted and where does it replicate and shed?
Pestivirus - Transmitted via semen - Replicates in respiratory and enteric tract - Sheds in respiratory and faeces
What is the equivalent of BVDV in sheep?
Border disease virus
What happens if BVDV infects during the first trimester?
(0-110 days) - embryonic death, resorption/abortion - possible persistent infection (PI calf)
What happens if BVDV infects during the second trimester?
(111-190 days) - Abortion/mummification - Possible PI - congenital deformities (esp 125-175 days)
What happens if BVDV infects during the third trimester?
(after 191 days) - occasional abortions/stillbirths/weak calves - predominately normal calves
How can BVDV be controlled and prevented?
Vaccination before pregnancy - Identify and remove persistently infected animals (antigen tests) - Eradication programs
What causes Bovine Herpesvirus-1 (BHV-1)?
Respiratory disease -> Infectious bovine rhinotracheitis (IBR)
Reproductive tract disease -> Infectious pustular vulvovaginitis (IPV) or Infectious balanoposthitis (IBP)
A cow has had an abortion at 4-8 months of gestation - It has a history of a respiratory infection a few weeks ago - On post mortem the foetus has necrosis of the liver and lung
What is a like diagnosis?
BHV-1
