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| − | {{review}}
| + | <big> |
| − | {{toplink
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| − | |backcolour =
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| − | |linkpage =Parasites
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| − | |linktext =PARASITES
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| − | |pagetype=Bugs
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| − | |sublink1=Protozoa
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| − | |subtext1=PROTOZOA
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| − | }}
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| − | <br> | |
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| − | ==''Babesia''==
| + | '''[[Babesia|''Babesia'']] |
| − | [[Image:Babesia Life Cycle.jpg|thumb|right|150px|''Babesia'' Life Cycle Diagram - Dennis Jacobs & Mark Fox RVC]] | |
| − | [[Image:Alternative Babesia life cycle diagram.jpg|thumb|right|150px|''Babesia'' Life Cycle - Mariana Ruiz Villarreal]]
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| − | *Infects a wide range of host species in different areas of the world
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| − | *Babesiosis has severe effects on cattle production in parts of the world
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| − | **Prevents European breeds from being successful in tropical regions where [[Ticks|ticks]] are endemic.
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| − | **Occurs sporadically in the UK and Ireland causing losses of around £8 million per year
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| − | '''Life Cycle'''
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| − | *Both [[Ticks#Disease Transmission|trans-stadial]] and [[Ticks#Disease Transmission|trans-ovarian]] transmission occurs
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| − | *Each female [[Ticks|tick]] produces 3000 eggs
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| − | *The [[Ticks|tick]] is the definitive host
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| − | *''Babesia'' multiplies in the red blood cells by '''budding'''
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| − | **Forms 2-4 daughter cells (species dependent)
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| − | **Giemsa blood smears can differentiate between species using 'Difquik' stain
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| − |
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| − | *''Babesia'' species are either small or large depending on the size of the daughter cells
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| − | *Small ''Babesia''
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| − | **E.g. ''B. divergens''
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| − | **E.g. ''B. gibsoni''
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| − | **Peripheral nucleus
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| − | **Obtuse angle
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| − | *Large ''Babesia''
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| − | **E.g. ''B. major''
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| − | **E.g. ''B. canis-complex''
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| − | **Central nucleus
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| − | **Acute angle
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| − | *Daughter cells disrupt the red blood cell and are released
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| − | **Spread and infect other red blood cells
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| − |
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| − | *Antigen is released which adsorbs onto other red blood cells
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| − | **Causes haemolysis and [[Pigmentation and Calcification - Pathology#Haemoglobin|haemoglobin pigmentation]]
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| − | **Causes haemolytic anaemia, haemoglobinuria and fever
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| − |
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| − | *Cattle
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| − | **Sudden onset
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| − | **Often fatal if untreated
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| − | **Causes 'pipestem' faeces
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| − | **Clumping of red blood cells in brain capillaries can occur causing neurological signs
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| − |
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| − | '''Epidemiology'''
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| − | *Determined by:
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| − | **Number of infected [[Ticks|ticks]] seeking a blood meal ('''tick pressure''')
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| − | **Calves under 9 months are refractory to disease
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| − | ***Can develop immunity if exposed without showing clinical signs
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| − | **'Premunity' (a good protective immunity) develops quickly in infected cattle causing a 'carrier state'
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| − | **Immunity can wane in the absence of re-infection
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| − | **Uninfected cattle remain susceptible
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| − | *Predisposing factors:
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| − | **Susceptible animals introduced into an infected area
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| − | **Infected [[Ticks|ticks]] introduced into a clean area
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| − | **Infected cattle introduced into an area with clean [[Ticks|ticks]]
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| − | **Temporary reduction in the [[Ticks|tick]] population decreasing the transmission rate (causing enzootic instability)
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| − | **Infected are transported or stressed in other ways, e.g. parturition
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| − | *In the UK
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| − | **Sporadic disease
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| − | **Enzootic instability
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| − | **Occurs mostly during the spring and autumn during periods of greatest [[Ticks|tick]] activity
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| − | **Occurs mostly in stressed cattle under 2 years old on rough grazing
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| − | **''B. divergens'' the most common species
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| − | **[[Hard Ticks - UK#Ixodes spp.|''Ixodes ricinus'']] is the vector
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| − | **[[Ticks#Disease Transmission|Trans-ovarial]] transmission to the next generation occurs
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| − | **''B. major'' occurs in South East England but is not pathogenic
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| − | ***Vector is [[Hard Ticks - UK#Important Hard Ticks|''Haemaphysalis'']]
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| − | *Overseas
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| − | **''B. bovis'' causes considerable losses in cattle in many tropical and sub-tropical areas
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| − | ***In Australia an attenuated vaccine is used
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| − | ***Vector is [[Hard Ticks - Overseas|''Boophilus'']]
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| − | **''B. bigemina'' causes problems in Africa and South America
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| − | ***Vector is [[Hard Ticks - Overseas|''Boophilus'']]
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| − |
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| − | *Dogs
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| − | **Complex epidemiology
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| − | **Recognised species are extending their endemic ranges due to the discovery of the small ''Babesia'' species, pet passport scheme and increased overseas travel
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| − | **Large species comprises 3 subspecies
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| − | ***''B. canis canis'' is the most important
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| − | ****[[Hard Ticks - Overseas|''Dermacentor'']] vector
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| − | ****Largely confined to southern Europe but is spreading
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| − | ***''B. canis'' uses [[Hard Ticks - Overseas|''Rhipicephalus'']] as a vector and is spreading northwards through Europe
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| − | ***''B. gibsoni'' is now established in the USA and South-East Asia
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| − | **British dogs have no immunity as no species are endemic to the UK so are highly susceptible if taken abroad
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| − | **Prevention of [[Ticks|tick]] bites by use of an 'Amitraz' collar is currently the best method of protection
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| − | *Horses
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| − | **2 species occur
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| − | **''B. equi'' is the most pathogenic
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| − | **Not endemic to the UK
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| − | **Serology using ELISA or IFAT to diagnose
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| − | *Sheep and goats
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| − | **Several species
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| − | **Little clinical significance
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| − | ===Enzootic Instability===
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| − | *Low rate of transmission
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| − |
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| − | *Few infected [[Ticks|ticks]]
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| − | *Infrequent exposure
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| − | *Immunity wanes or is completely absent in many individuals
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| − | *Low levels of herd immunity
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| − | *'''Higher''' incidence of disease
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| − | ===Enzootic Stability===
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| − | *High rate of transmission
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| − |
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| − | *Many infected ticks
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| − |
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| − | *Frequent exposure boosts immunity
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| − | *High level of herd immunity
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| − |
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| − | *'''Lower''' incidence of disease
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| | ==''Cytauxzoon felis''== | | ==''Cytauxzoon felis''== |