African Horse Sickness Flashcards
Describe the virus causing AHS
Double stranded, non-enveloped, RNA virus
Trtansmission of AHS
Midges
Culicoides imicola
Culicoides bolitinos
ID this vector
Midge
Cullicoides imicola
Transfers AHS virus
Most likely diagnosis
African Horse Sickness
Number of serotypes of AHS
9 destinct serotypes
Major forms of AHS
There are 4 major forms:
- Peracute / pulmonary (dunkop): mortality 95%
- Subacute / Cardiac (Dikkop): 50% mortality
- Mixed: 70% mortality
- Fever: (recovery)
Vaccine protocol for AHS
Every 6 months up to 2 years
Then anually: last one given before end of Octber
(required by law)
What does the AHS vaccine consist of
Polyvalent, attennuated live vaccine:
- Trivalent coantining: 1,3,4
- Quadrivalent: 2,6,7,8
Cross-protection: 8-5, 6-9
When is peak vector activity /
Most likely time to see AHS
After heavy rains followd by dry periods:
Wet months of Feb, March, April
Most likely reservoir animals for AHS virus
Zebras
Donkeys
Gros pathological changes with AHS
- Heavy, non-collapsable lungs
- Yellow, gelatinous odoema of subcut and intramuscular tissue
- Oedema of nuchal ligament
- Hydrothorax
- Hydropericardium
- Diffuse haemorrhage & petechaition
- Lymphadenomegaly
CBC changes
Leukopaenia
Thrombocytopenia
Increased PCV / Increased Ht
Clotting test changes
- Increased fibrin degradation products
- Prolonged prothrombin
- Prolonge prothrombin
- Prolonged activated partial thromboplastin
- Prolonged thrombin
Confirmatory tests for AHS
Antigen testing:
- RT-PCR
- ELISA
Serotyping of virus
- ELISA
- RT-PCR
Therapeutic goals
Supportive care:
Furosamide
NSAID’s
Corticosteroids
Plasma from a horse that’s been vaccinated
