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| − | {{unfinished}} | + | {{frontpage |
| − | | + | |pagetitle =Rickettsiales |
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| | + | |contenttitle =Content |
| | + | |contentbody =<big><b> |
| | + | <categorytree mode=pages>Rickettsiales</categorytree> |
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| | ===Overview=== | | ===Overview=== |
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| | *Host and cell type specificity | | *Host and cell type specificity |
| | *Q fever and Rocky Mountain spotted fever are zoonoses | | *Q fever and Rocky Mountain spotted fever are zoonoses |
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| | ===Characteristics=== | | ===Characteristics=== |
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| | *''Rickettsiaceae'' have cell walls that contain peptidoglycan; they target endothelial cells and leukocytes | | *''Rickettsiaceae'' have cell walls that contain peptidoglycan; they target endothelial cells and leukocytes |
| | *''Anaplasmataceae'' lack cell walls; they target erythrocytes | | *''Anaplasmataceae'' lack cell walls; they target erythrocytes |
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| | ===Epidemiology=== | | ===Epidemiology=== |
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| | *Transovarial or trans-stadial transmission occurs in the arthropod vectors | | *Transovarial or trans-stadial transmission occurs in the arthropod vectors |
| | *Most ricketsiae have limited survival in the environment, apart from ''Coxiella burnetii'', which undergoes aerosol transmission | | *Most ricketsiae have limited survival in the environment, apart from ''Coxiella burnetii'', which undergoes aerosol transmission |
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| | ===Pathogenesis and pathogenicity=== | | ===Pathogenesis and pathogenicity=== |
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| | *''Ehrlichia'' target leukocytes or platelets, and inhibit phagosome/lysosome fusion | | *''Ehrlichia'' target leukocytes or platelets, and inhibit phagosome/lysosome fusion |
| | *''Anaplasmataceae'' localise within vacuoles or on the surface of red blood cells; they may alter red cell antigens causing immune-mediated damage. Anaemia may result from haemolysis or removal of red blood cells | | *''Anaplasmataceae'' localise within vacuoles or on the surface of red blood cells; they may alter red cell antigens causing immune-mediated damage. Anaemia may result from haemolysis or removal of red blood cells |
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| | ===Identification=== | | ===Identification=== |
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| | *Inoculation of susceptible animals | | *Inoculation of susceptible animals |
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| − | [[Rickettsia rickettsii]] | + | [[Category:Bacterial Organisms]] |
| − | | + | [[Category:To_Do_-_Bacteria]] |
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| − | ===Canine monocytic ehrlichiosis===
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| − | *Generalised disease of dogs in tropical and subtropical regions
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| − | *Caused by ''Ehrlichia canis''
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| − | *The brown tick, ''Rhipicephalus sanguineus'', is the main vector
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| − | *Dogs may carry the organism for 2 years after resolution of clinical signs
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| − | *Clinical signs
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| − | **Incubation period of 3 weeks
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| − | **Acute, subclinical or chronic phases
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| − | **Acute phase: fever, thrombocytopenia, leukopenia and anaemia
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| − | **Subclinical phase: low blood cell numbers but minimal clinical signs; can progress to a severe disease, tropical canine pancytopenia
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| − | **Chronic phase: bone marrow depression, haemorrhages, neurological disease, peripheral oedema, emaciation and hypotensive shock
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| − | *Diagnosis
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| − | **''E. canis'' morulae present in mononuclear cells in Giemsa-stained blood smears
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| − | **Rising antibody titre detected by indirect immunofluorescence
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| − | **Culture in canine macrophages
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| − | *Treatment and control
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| − | **Doxycycline for 10 days
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| − | **Fluid therapy or blood transfusion
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| − | **Prophylactic tetracyclines
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| − | ===Canine cyclic thrombocytopenia===
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| − | *Caused by ''Ehrlichia platys''
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| − | *Affects platelets
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| − | *Recurrent thrombocytopenia, but dogs usually asymptomatic
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| − | *Seroconversion detected by indirect immunofluorescence
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| − | ===Potomac horse fever===
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| − | *Caused by ''Ehrlichia risticii''
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| − | *Occurs during the summer
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| − | *Fluke vector
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| − | *Infects epithelial cells of colon and [[Monocytes - WikiBlood]], macrophages and mast cells
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| − | *Clinical signs
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| − | **Fever, anorexia, depression, diarrhoea, colic, leukopenia, laminitis
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| − | *30% mortality
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| − | *Can cause abortion
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| − | *Hyperaemia of large intestine at post mortem
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| − | *Diagnosis
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| − | **Seroconversion detected by indirect immunofluorescence or ELISA
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| − | *Treatment and control
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| − | **Oxytetracycline for 1 week
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| − | **Inactivated vaccines
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| − | ===Equine granulocytic ehrlichiosis===
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| − | *Caused by ''E. equi''
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| − | *Clinical signs: fever, depression, ataxia, limb oedema, icterus and petechial haemorrhages
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| − | *Low mortality
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| − | *Diagnosis: presence of morulae in [[Neutrophils - WikiBlood|neutrophils]] during early disease; seroconversion; leukopenia
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| − | *Treatment: tetracyclines
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| − | ===Bovine petechial fever===
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| − | *Caused by ''E. ondiri''
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| − | *Disease of cattle in Kenya and other countries of East Africa
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| − | *Tick vector
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| − | *Clinical signs: intermittent fever, depressed milk yield, petechiation of mucous membranes and conjunctiva
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| − | *Death from pulmonary oedema
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| − | *Diagnosis: presence of organisms in Giemsa-stained blood smears
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| − | *Treatment: tetracyclines
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| − | ===Tick-borne fever===
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| − | *Caused by ''E. phagocytophila''
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| − | *Affects ruminants in Europe
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| − | *The tick ''Ixodes ricinis'' is the main vector
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| − | *Animals remain carriers for up to 2 years, but are immune to reinfection
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| − | *Clinical signs
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| − | **Incubation period of 2 weeks; recovery in 2 weeks
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| − | **Fever, anorexia, reduced growth rates in young animals
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| − | **Reduced milk production, abortion, still birth
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| − | **Leukopenia and thrombocytopenia
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| − | **Causes immunosuppression in young lambs causing susceptibility to tick pyaemia and louping ill
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| − | *Diagnosis
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| − | **Intracytoplasmic morulae in [[Neutrophils - WikiBlood|neutrophils]] of Giemsa-stained blood smears during acute phase
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| − | **Seroconversion detected by immunofluorescence
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| − | *Treatment and control
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| − | **Oxtetracycline
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| − | **Tick control
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| − | **Prophylactic tetracyclines for lambs during first few weeks of life
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| − | ===Heartwater===
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| − | *Severe disease of ruminants in sub-Saharan Africa caused by ''Cowdria ruminantium''
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| − | *Vectors include ''Amblyomma'' ticks
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| − | *Carrier status can occur for up to 8 months in adult cattle and wildebeest
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| − | *Clinical disease in calves and lambs
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| − | *Clinical signs
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| − | **Incubation period 4 weeks
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| − | **Acute fever
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| − | **Neurological signs including chewing, twitching of eyelids, circling, high-stepping gait, convulsions and recumbency; can be fatal
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| − | **Subacute cases suffer from hydropericardium, hydrothorax and pulmonary oedema and congestion; splenomegaly and haemorrhages may occur
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| − | *Diagnosis
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| − | **Clinical and post mortem findings in endemic areas suggestive
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| − | **Orgnisms present in nuclei of endothelial cells in Giemsa-stained brain tissue
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| − | **PCR, indirect immunofluorescence, ELISA and western blot
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| − | *Treatment and control
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| − | **Tetracyclines during early disease
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| − | **Immunisation using infected blood
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| − | ===Bovine anaplasmosis===
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| − | *Disease of cattle in tropical and sub-tropical regions caused by ''Anaplasma marginale''
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| − | *Carrier status in endemic regions with clinical disease occuring in times of stress
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| − | *High mortality rate in naive adult cattle
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| − | *Morulae localise inside red blood cells close to the cell membrane
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| − | *Transmitted via the ''Boophilus'' tick as well as flies and contaminated instruments
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| − | *Clinical signs
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| − | **Inculbation period 2-12 weeks
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| − | **Anorexia, fever, depression, reduced milk yield, weight loss
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| − | **Anaemia and icterus
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| − | **Sudden death from hypoxia can occur
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| − | *Diagnosis
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| − | **Clinical signs and haematology suggestive
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| − | **Organisms present in erythrocytes of Giemsa-stained blood smears
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| − | **Immunofluorescence of blood smears, PCR, serology
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| − | *Treatment and control
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| − | **Long-acting oxytetracycline or imidocarb early in the disease
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| − | **Supportive therapy
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| − | **Vaccination of animals being introduced into an endemic region
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| − | ===Feline infectious anaemia===
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| − | *Caused by ''Mycoplasma haemofelis ( ''until recently, known as'' Haemobartonella felis)
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| − | *Organism found on surface of erythrocytes
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| − | *Common in roaming tom-cats of 1-3 years old
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| − | *Possibly transmitted via bite wounds or arthropods
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| − | *Recoverd cats become carriers
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| − | *Clinical signs
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| − | **Peracute disease is associated with severe anaemia and immunosuppression, and can be rapidly fatal
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| − | **Fever, anaemia, depression, weakness and jaundice occur in the acute form
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| − | **Anaemia, lethargy and weight loss occur in the chronic form
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| − | **Recovery can occur with a regenerative bone marrow response
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| − | **Severe feline infectious anaemia may occur in the presence of feline leukaemia virus
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| − | *Diagnosis
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| − | **Organism intermittently seen on the surface of red blood cells in Giemsa-stained blood smears
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| − | **Immunofluorescence of blood smears
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| − | **Reduced packed cell volume; regenerative anaemia
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| − | *Treatment
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| − | **Doxycycline for 3 weeks early in the course of the disease
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| − | **Blood transfusion
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| − | **Flea control
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| − | ===Canine haemobartonellosis===
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| − | *Dogs infected with ''Haemobartonella canis'' usually asymptomatic
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| − | *Acute haemolytic anaemia may occur in dogs after splenectomy, immunosuppressive drug therapy or immunosuppressive infections
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| − | ===Q fever===
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| − | *Caused by ''Coxiella burnetti''
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| − | *Influenza-like disease of humans in contact with farm animals
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| − | *Transmitted to humans by inhalation from parturient sheep, goats and cattle
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| − | *Organisms replicate in female genital tract and mammary glands of ruminants
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| − | *Shedding occurs in uterine discharges, foetal fluid and milk
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| − | *Infections in animals usually subclinical
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| − | *Sporadic abortions occur in sheep, goats, cattle, cats
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| − | *Infertility may result in ruminants, as well as placentitis or endometritis
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| − | *Hepatitis, myocarditis and interstitial pneumonia may occur in affected foetuses
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| − | *Diagnosis: MZN-stained smears of placental tissue and uterine discharges; immunofluorescence; PCR; culture; serology
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| − | *Control: disposal of infected placenta and separation of pregnant ruminants; inactivated vaccines
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| − | [[Category:Infectious_Agents]]
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