Arthropod-Vector Borne Infectious Disease in Large Animals Flashcards
What diseases do ticks transmit?
Babesia spp Anaplasma phagocytophila Louping ill virus Staph pyogenes Borrelia burgdorferi (Lyme Disease)
What babesia spp infect cattle?
B. divergens, B. bigemina, B/ bovis
What is the habitat that ticks inhabit?
Rough pasture, moorland and heathland, high humidity, presence other vertebrate hosts
What is the tick feeding season?
Mainly March to June with peak activity in April/May
What are the clinical signs of bovine babesiosis?
Pyrexia, anaemia, jaundice, haemoglobinuria, death (24 hours acute illness), intravascular haemolysis
How is endemic stability achieved with bovine babesiosis?
Calves <6 months resistant to disease and develop immunity and asymptomatic state
How is bovine babesiosis diagnosed?
Blood smear
PCR
Serology
How is bovine babesiosis controlled?
Acaricides, tick habitat removal, avoid certain pastures/deliberately graze youngstock on known tick pastures, live attenuated vaccines available
How is bovine babesiosis treated?
Anti-parasitic drug = imidocarb
Supportive
What is Anaplasma phagocytophila?
Tick borne fever
Rickettsial parasite of leukocytes affecting cattle, sheep, goats, horses and dogs
What disease does Anaplasma phagocytophilia cause in people?
Human granulocytic anaplasmosis
What is the pathogenesis of tick borne fever?
Intracytoplasmic inclusions in neutrophils, eosinophils and monophils resulting in immune suppression and leukopenia, neutropenia and decreased phagocytosis
What are the three outcomes of tick borne fever?
Asymptomatic
Increased susceptibility to other diseases
Fever and abortions in sheep and goats and fever, milk drop and respiratory signs in cattle
What is Louping ill virus?
Only Flavivirus endemic to UK in upland areas of Scotland, Wales, NW and SW England
What are the signs of louping ill virus?
Pyrexia and paresis in sheep
How is equine infectious anaemia transmitted?
Horse and stable flies
Saliva, nasal secretions, faeces, semen, ova and embryos
Fomites
In utero
What are the clinical signs of acute EIA?
Fever, thrombocytopenia, lethargy, inappetence, can be fatal, susequent inapparent infection or recurrent disease episodes
What are the clinical signs of chronis EIA?
Anaemia, thrombocytopenia, weight loss, dependent oedema, occasionally neuro signs
How is EIA diagnosed?
Positive serology confirms as it is a persistent virus
What are the characteristics of bluetongue virus?
Non-enveloped segmented RNA virus with 25 serotypes
Transmitted by Culicoides spp
What is the pathogenesis of BTV?
Haemorrhagic disease and replicated in endothelial cells and mononuclear phagocytes
What are the clinical signs of BTV?
Pyrexia, salivation, oedema face and lips, cyanosis of tongue, coronary band haemorrhages in sheep
Cattle less severely affected but get oronasal crusts and erosions
How is BTV diagnosed?
Spleen, red bone marrow, liver, heart blood, LN biopsy
Blood in heparin for virus isolation/RT-PCR
Serum for ELISA
What is the life-cycle of West Nile Virus?
Normally maintained in mosquito-bird cycle with horses and humans being incidental hosts
What range of symptoms are seen in West Nile Virus in horses and people?
Asymptomatic to fatal encephalitis
What are the clinical signs of Schmallenberg Virus?
Mild disease in adults with pyrexia, milk drop and diarrhoea
Congenital defects in lambs, calves and kids - hydraencephaly, arthrogryposis, dummy calf
What causes Crimean-Congo Haemorrhagic fever?
Bunyavirus CCHFV
Where is CCHF endemic?
Africa, parts of Europe, Asia and the Middle East
