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Also Known As: '''''Gall sickness''''' – '''''Gallsickness''''' – '''''Tick fever''''' (Australia) – '''''Tristeza''''' (Portugal)
Caused by: '''''[[Anaplasma marginale]] – Anaplasma ovis – A. ovis – Ehrlichia bovis
=Introduction=
==Introduction==
Anaplasmosis is a ruminant disease caused by the '''rickettsial''' pathogens ''[[Anaplasma marginale]]'', ''A. ovis'', ''A. mesaeterum'' and ''Ehrlichia bovis''.
[[File:Anasmosis.jpg|thumb|200px|right|''Rickettsia'' sp. inside tick haemolymph cells (sourced from Wikimedia Commons)]]
Anaplasmosis is a ruminant disease caused by the [[:Category:Rickettsiales|'''rickettsial''']] pathogens ''[[Anaplasma marginale]]'', ''A. ovis'', ''A. mesaeterum'' and ''Ehrlichia bovis''.
These rickettsial parasites reside exclusively within the '''[[erythrocytes| red blood cells]]''' of their hosts.
These rickettsial parasites reside exclusively within the '''[[erythrocytes| red blood cells]]''' of their hosts.
This disease is notifiable to the World Organisation of Animal Health ([http://www.oie.int/ OIE])
This disease is notifiable to the World Organisation of Animal Health ([http://www.oie.int/ OIE])
=Signalment=
==Signalment==
The resistance of Bos indicus cattle to ticks may reduce the rate of transmission in this breed.
The resistance of ''Bos indicus'' cattle to [[:Category:Ticks|ticks]] may reduce the rate of transmission in this breed.
No other breed predilection is evident.
No other breed predilection is evident.
Exposure before this age often results in lifelong, protective immunity providing endemic stability even in the presence of disease and vectors.
Exposure before this age often results in lifelong, protective immunity providing endemic stability even in the presence of disease and vectors.
No marked age vulnerability appears to exist in sheep and all ages appear to acquire disease equally although it is usually mild and is exacerbated by stress.
No marked age vulnerability appears to exist in sheep and all ages appear to acquire disease equally although it is usually mild but is exacerbated by stress.
=Distribution=
==Distribution==
Anaplasmosis occurs in '''tropical''' and subtropical regions, particularly South and Central America, USA, Africa, Australia and Southern Europe. This climate supports the insect and mechanical vectors required for transmission of the parasite.
Anaplasmosis occurs in '''tropical''' and subtropical regions, particularly South and Central America, USA, Africa, Australia and Southern Europe. This climate supports the insect and mechanical vectors required for transmission of the parasite.
=Transmission and Lifecycle=
==Transmission and Lifecycle==
Anaplasmosis is '''not directly contagious''' and most transmission occurs via [[ticks]].
Anaplasmosis is '''not directly contagious''' and most transmission occurs via ticks.
Any stage of the tick’s lifecycle can become infected with Anaplasma organisms.
Any stage of the tick’s lifecycle can become infected with Anaplasma organisms.
After development within the tick, the final infective stage is within the '''salivary glands''' and is injected into the bloodstream of the host when the parasite bloodfeeds. Male ticks are more mobile and longer lived therefore may play a bigger role.
After development within the tick, the final infective stage is within the '''salivary glands''' and is injected into the bloodstream of the host when the parasite bloodfeeds. Male ticks are more mobile and longer lived therefore may play a bigger role.
Anaplasmosis is not considered zoonotic.
Anaplasmosis is not considered zoonotic.
=Clinical Signs=
==Clinical Signs==
'''Cardiovascular'''
'''Cardiovascular'''
Profound anaemia resulting in tachycardia and dyspnoea. Congestion of mucous membranes.
:Profound anaemia resulting in tachycardia and dyspnoea. Congestion of mucous membranes.
'''Gastrointestinal'''
'''Gastrointestinal'''
Anorexia and mucoid diarrhoea, Rumenal atony, Excess salivation.
:Anorexia and mucoid diarrhoea, rumenal atony, excess salivation.
'''Urinary'''
'''Urinary'''
Red, brown or pink urine
:Red, brown or pink urine
'''Neurological signs'''
'''Neurological signs'''
Shivering, fasciculations, ataxia, seizures, syncope
:Shivering, fasciculations, ataxia, seizures, syncope
'''Reproductive'''
'''Reproductive'''
Abortion, infertility, agalactia
:Abortion, infertility, agalactia
'''Other'''
'''Other'''
Swelling of the head, face and ears, General paresis/paralysis, Rough hair coat
:Swelling of the head, face and ears, general paresis/paralysis, rough hair coat
Signs are often severely exacerbated by '''exercise'''.
Signs are often severely exacerbated by '''exercise'''.
=Diagnosis=
==Diagnosis==
Identification of the organism within the erythrocytes on a thin '''blood smear''' with Giemsa staining is both uncomplicated and definitive.
Identification of the organism within the erythrocytes on a thin '''blood smear''' with Giemsa staining is both uncomplicated and definitive.
A positive result is deemed as '''>5% red blood cells infected''' or accompanying anaemic signs. The number of infected cells doubles every 24-48h and may reach 90%.
A positive result is deemed as '''>5% red blood cells infected''' or accompanying anaemic signs. The number of infected cells doubles every 24 - 48h and may reach 90%.
The degree of parasitaemia is much lower in sheep and goats.
The degree of parasitaemia is much lower in sheep and goats.
Urine is dark yellow/brown due to the presence of [[Bilirubin | bilirubin]].
Urine is dark yellow/brown due to the presence of [[Bilirubin | bilirubin]].
=Treatment=
==Treatment==
'''Oxytetracycline''' and '''Imidocarb''' are both highly effective and prompt treatment usually ensures survival for all but the most severely affected. Note that imidocarb is not approved for use in some countries.
'''Oxytetracycline''' and '''Imidocarb''' are both highly effective and prompt treatment usually ensures survival for all but the most severely affected individuals. Note that imidocarb is not approved for use in some countries.
Supportive treatment such as '''blood transfusions''' and appetite stimulants in severe cases may be required.
Supportive treatment such as '''blood transfusions''' and appetite stimulants in severe cases may be required.
A long combined course of imidocarb and oxytetracycline can also be used to eliminate the carrier state.
A long combined course of imidocarb and oxytetracycline can also be used to eliminate the carrier state.
=Control=
==Control==
'''Vaccines''' against anaplasmosis are available, all are derived from the blood of infected cattle. Both live and killed forms are available.
'''[[Vaccines]]''' against anaplasmosis are available, all are derived from the blood of infected cattle. Both live and killed forms are available.
'''Detection''' and '''culling''' or '''treatment''' of '''carrier animals''' is essential.
'''Detection''' and '''culling''' or '''treatment''' of '''carrier animals''' is essential.
Take care when performing veterinary and husbandry procedures to prevent iatrogenic transmission with contaminated instruments.
Control of the '''[[Ticks | tick]] vector is viable but expensive.
[[Tick Control|Control of the tick vector]] is viable but expensive.
=References=
==References==
<references/>
<references/>
Animal Health & Production Compendium, Anaplasmosis datasheet, accessed online 02/06/2011 @ http://www.ahpc.org/
Animal Health & Production Compendium, Anaplasmosis datasheet, accessed online 02/06/2011 @ http://www.ahpc.org/
[[Category:Lymphoreticular and Haemoatopoietic Diseases - Cattle]]
[[Category:CABI Expert Review]]