LA Arthropod Borne Infectious Dz Flashcards
What is Redwater fever?
- Bovine Babesiosis = tick fever
- Babesia spp. B divergens, bigemia, bovis
- Ixodes ricinis common vetor
Tick habitat
- rough pasture
- moorland and heathland
- high humidity
- presence of other vertebrate hosts
When is the tick feeding season?
- March - June, peak April-May
- also some sutumn feeding ticks but all activity ceases in winter
What type of haemolysis is associated with? Other clinical signs? What is severity dependant on?
- anaemia
- pyrexia
- jaundice
- death 24hr acute illness
- hemogolobinuria
> severity varies w/ previous exposure and ENDEMICITY (endemic stability) - calves
Dx of bovine babesiosis?
> Blood smear
- sample from peripheral (ear/tail) capillaires
- thin smear (airdried and ifxed)
- thick smear (not fixed, allows concentration of parasites)
- morphological variability (annular stages, pear-haped (pyriform) trophozoites singly or in pairs and filamentous/amorphous shapes)
PCR
- gold standard
Serology
- surveilance and export certification
- uually indirect fluorescent Ab (IFAT) or ELISA
- Control of bovine babesiosis?
- acaricides can v incidence (but only need 1 infected tick for transmission!)
- tick habitat removal
- avoid pastures
- deliberately graze young stock on known Babesia/tick pastures
- live attenuated available
Tx bovine babesia
- Anti-parasite eg. Imidocarb
- - Supportive tx
Is BAbesia zoonotic?
- YEEESSSS - B. Divergens causes rare, serious, acute dz in splenectomised people
What does A. phagocytophila (used to be ehrlichia phagocyt) cause in cattle?
> Tickborne fever
- RIckettsial parasite of leukocytes
- main vector IXodes Ricinis
- affects sheep(goats), cattle, horses, dogs
- maintained in sylvatic lifecycle (tick and wildlife)
cause of ‘human granulocytic anaplasmosis’
pathogensis of Tick-borne fever?
> Intracytoplasmic inclusions: Neutrophils, eosinophils, monocytes
Immune suppression (leukopenia, neutropenia, v phagocytosis) ->
- Asymptomatic (mostly)
- ^ Susceptibility to dz eg. tick pyaemia [s. pyogenes], louping ill, pasteurella pneumonia
- Tick Borne fever (fever and abortion in sheep and goats, fever milk drop, respiraotry signs in cattle
Clinical signs of Tick-borne fever (anaplasma phagocytophila)
- aymptomatic
- ^ susceptibility of other dz
- tick borne fever (fever and abortion sheep and goats/fever, milk drop and respiratory signs in cattle)
What is the only endemic flavivirus of the UK?
Louping ill virus
- upland areas Scotland, Wales, NW/SW england
Which animaals are affected by louping ill?
- sheep
- young unvaccinated
Clinical signs of Louping ill?
- neuro signs
- pyrexia and paresis
Is louping ill zoonotic?
Yes but
- Which disease is related to Louping ill and how does it differ?
- TBEV (endemic Europe and Asia)
> tick borne encephalitis virus - does not cause disease in livestock
- same vector (Ixodes Ricinis)
Is EIA zoonotic?
NO
What transmits EIA?
- big fat flies (stablefly, horseflies) limited range
- saliva, nasal secretions, feacces, semen, ova, embreyos
- fomites
- in utero
What type of virus is EIA?
Lentivirus (=FIV, HIV etc.)
- RNA virus
- infects macrophages
Is EIA notifiable?
YEs [defra], and usually euthanased to prevent spread
- imported animals be aware
Incubation period of EIA?
-
Clinical signs of acute and chronic EIA?
> acute - can go un-noticed - fever, thrombocytonpenia, lethagy, inappetence - cann be fatal - subsequent inapparent nfection or recurrent dz episodes > chronic - lifelong carrier state - anaemia - thrombocytopenia - weight loss - dependant oedema \+- neuro signs - episodes subside and become inapparent carriers
Dx of EIA?
> serology (since persistent virus, if it has ever been affected hence sero+ then stilli nfected)
- NB: Ab respnse may not develop for 10-14d most seroconvert after 45d
AGID Coggins test to check
Tx EIA?
- NO vax
- cull
What type of virus is bluetogue?
- non enveloped segmented RNA virus
- 25 serotypes
What is bluetongue transmitted by?
Culicoides midges
- C. imicola main vector S. Europe
- C. obseletus/pulicares N Europe
Which strain of bluetongue casued the UK outbreak in 2007?
BTV 8
Pathogenesis of BTV?
- Haemorrhagic dz (direct and indirect effects of virus)
- replicates in endothelial cells and mononuclear phagocytes
- prolonged cell asociated viraemia
Which species are affected by BTV?
- Ruminants
- sheep more prone to developing clinical signs , cow can be asymptomatic carriers of virus.
- NOT zoonotic
Clinical signs of BTV?
> sheep - pyrexia - salivation - oedema face and lips - cyanosis of tongue - coronary band haemorrhage > cows - less severely affected - may be asymptomatic - role in transmission - BTV 8 in N europe unusual since clinical signs in large no. infected cattle - oronasal crusts and erosion
Samples and dxx for BTV esting?
- tissues: spleen, red bone marrow, liver, heart blood, LNs
- blood in heparin (virus isolation/RT-PCR)
- serum (for serology using BTV specific competitive ELISA)
Is Bluetongue notifiable?
- yes
Control of bluetonuge virus?
- movement restrictions
- voluntary vaccination programme
> successful control
Are BTV vax available?
- yes inactivated for use in a BTV free area
What is the normal West Nile Virus cycle ? Incidental hosts?
- bird mosquito cycle
- morbidity and mortality seen in birds
> horses and people incidental infection
CLinical signs of WEst Nile Virus?
asymptomatic -> fatal encephalitis
- CNS signs
Where has a WNV outbreak occourred previously?
- america spread E- W coast within ~10y
Where are cases of WNV sill seen?
USA
What type of virus is Shmallenburg?
- Orthobunyavirus
Vector of Shmallenburg?
- ???
Cliniical signs of Shmallenburg?
> adults - mild dz adults ( cattle>sheep/goats) - cattle > sheep and goats - pyrexia, milk drop, D+ > neonates - congenital defects (CNS and musculoskeletal) abortions, stillbirths (lamb>calves/kids)
What tropism does shmallenburg show?
Neuro
- lack of white matter
- hydrancephaly
- arthrogryposis, torticolosis, brachygnathia inferior
- dummy calf
Are bunyaviridae zoonotic?
Several are > CCHF > RVFV > Sin Nombre - SHmallenburg studies found no evidence for zoonotic risk but monitor and precautionary biosecurity
Is there a vax for Shmallenburg?
yes but not massive usage atm.
Where has shmallenburg RNA been found?
semen
What is Crimean-Congo Hameorrrhagic Fever?
- Bunyavirus CCHFV
- endemic in many countries (AFrica, EUrope, Midle East and Asia)
- Wild and domestic animals (cattle, goats, sheep, hares) are amplifying hosts for the virus
- Tick-transmitted (31 tick spp)
- No dz in animals but may be source of infection to people
> infected ticks could come in on migrtory birds or livestock
Which pathogens can ticks vector? Ixodes ricnis
- Babesia
- Anaplasma phagocytophila
- louping ill virus
- staph pyogenes
- Borrelia Burgdorferi (Lyme dz)
