w/c 30-June-14 Flashcards
Where are leukocytes produced?
Bone marrow- all cell lines
Spleen and liver = potential to produce all leukocyte lines
Thymus, spleen, LN = most differentiation of lymphoid
Bursa of Fabricus function
Secondary lymphoid tissue in birds
Along with thymus, spleen and LN = differentiation of lymphoid cells.
When PCV tube is spun down, the layer where the leukocytes are is known as the…
Buffy coat. Is between the bottom layer (erythrocytes) and top layer which is the plasma
Why can’t leukocyte counts be done on a machine for reptile/avian blood?
Machine counts nucleated cells. Avian/Reptile blood=nucleated cells therefore falsely high.
Why do you get a neutrophillia from stress?
Neutrophils are ‘washed’ off their attached position on the blood vessel wall.
CNP to MNP Normal RATIO =
How does this differ between cats/dogs?
Circualting to Marginated neutrophil pool
Normally 1
i.e. same amount marginated as circulating but in CATS can be 3!!
therefore stress related neutrophillia
Neutrophil half life
5-10 HOURS
What is a left shift
If demand hgi, more immature neutrophils released i.e. MORE BANDS or earlier, known as a left shift.
When would you see toxic changes of neutrophils?
When they are being produced too quickly e.g. poorly developed nucleus or basophillia.
Cells can appear more blue or Dohle bodies might be present (all toxic change)
Difference between degenerate and toxic neutrophils
Degenerative neutrophils: In tissue, fighting with bacteria, bacterial toxins.
Toxic: in peripheral blood due to accelerated production. NO NEED FOR TOXINS!
Classification of regenerative left shift
Left shift: more immature neutrophil in circulation
Regenerative left shift = neutrophilia. Segemented > Bands
Classification of degenerative left shift
Left shift: more immature neutrophil in circulation.
Degenerative left shift: Neutropenia
Bands > Segemented
Significance of degenerative left shift
Severe condition. Start antibiotics!
Bands in circulation but still neutropenia.
Means dogs/cat have used up their storage pool
Horses/Cow significance of degenerative left shift
Horses and Cows don’t have the storage pool that dogs/cats have therefore tend to start off with a deg left shift (still need antib to help in first few days) then will tend to become regen after few days
Why is a degenerative left shift more severe in dogs/cats than large animals
Dogs/Cats have storage pool.
Horses/Cows don’t therefore start off with degen left shift while bone marrow inc production.
In dogs/ cats means it has used up storage and bone marrow is not keeping on top.
Both need antibs to start off.
Right shift is indicated by
Hypersegementation of the nucleus
Pet Travel Scheme (PETS) =
Required to protect individual pets but also UK disease status
Requires rabies and tape worm treatment but NO LONGER REQUIRES TICK TREATMENT (from Jan 2012)
Which tick born pathogens are endemic to UK (2) and how do they differ?
- Borrelia burgdorferi = Spirochete = Ixodes ricinus. Lyme disease
- Anaplasma phagocytiohillium = Rickettsial = Ixodes ricinus= Similar to E.canis but less severe
Which tick vector transmits Babesia canis/ Babesia gibsoni and Ehrlichia canis (all NON endemic to UK)
Rhipicephalus sanguineus
Ehrlichia canis: Rickettsial (causes Thrombocytopenia)
B. canis is more severe than B.gibsoni = PROTOZOAL
Large babesia / small babesia example
Protzoal.
Large babesia: B. canis
Small babesia: B. gibsoni (S. eruope)
V. uncommon in cats
Babesia pathogenesis
Within ticks, Babesia is transmitted trans-stadially and trans-ovarially.
Sporozoites injected from tick salivary glands
Enter circulation, endocytotosed by RBC
Immune-mediated
Cattle Babesia species =
Cattle and rodent reservoir are more important causes of human Babesiosis.
B. divergens = cattle.
Clinical signs of Babesiosis
Those of haemolytic anaemia:
Lethargy, Depression, Inappetence, Icterus, Splenomegaly, Tachycardia/Tachypnoea
Treatment of Babesiosis - does it differ between type of pathogen
Diagnosis: Microscopic identification (low sensitivity)
PCR or Serology (Ab test/ ELISA)
TREATMENT: Imidocarb diproprionate. Large forms (B. canis): Rapid clinical response Small forms (B. gibsoni) : Cure uncommon; relapses occur
Incubation period for Ehrilichia canis
Acute and Chronic signs
1-3 WEEKS
Acute phase: Vasculitis and immune destruction –> thrombocytopenia. Speen and LN enlargement. CNS / Occular signs.
Can be cleared or become sub-clinical carrier = chronic = bone marrow destruction, pancytopenia
Rikettsia =
Small obligate intracellular gram negative bacteria.
Monocytic: Ehrilichia Canis
Thrombocytic: Anaplasma platays
Granulocytic: Anaplasma phagocytophilium
Diagnosis and Treatment of Ehrlichia canis
Morulae in monocytes in blood smears or macrophages. Thrombocytopenia. IFA/ELISA
Treatment: Tetracycline/Chloramphenicol for 28 days. Tick-control
A. phagocytophilium
Signs in dogs (very rare in cats)
Mild/moderate thrombocytopenia, lymphopenia, mild anaemia, natural chronic infection not been seen. Secondary infections?
Zoonosis.
Borreliosis in dogs
Co-infections common *e.g. A.phagocytophilia Lethargy, Anorexia and Pyrexia. Inflamm polyarthritis. Lymphadenopathy Treatment: Doxycycline/Amoxicillin
Canine Leishmaniosis pathogenesis
Target tissue: Macrophages/
Systemic infection in hemolymphatic organs
Parasite persistence = chronic infection
Signs may develop MONTHS-years are infection
-weight loss/wasting, skin disease, lymphadenopathy, splenomegaly
ZOONOSIS
Diagnosis of Leishmania
Amastigotes in FNA of reactive LN.
Serology- high Ab
PCR- Bone marrow, LN, skin, spleen.
PROTEINURIA
Treatment for Leishmania
Often clinical remission but persistant parasitemia.
Meglumine antimoniate + allopurinol
Prolonged treatment
Consider euth due to zoonotic risk.
PREVENTION: Sandfly avoidance: Imidacloprid/Permethrin
PPP for Diroflaria immitis
Endemic in Europe. PPP is 6 months
Mosquito
Occupy R side of heart and pulmonary artery
ZOONOTIC
Prophalyaxis for animals travelling abroad
Selemectin (strong hold)
Milbemycin (program plus/ Milbemax)
Moxidectin (advocate)
Tx if already infected:
Symptomatic (treat CHF), Adulticide , Microfilarial
Don’t want to kill all at same time as will clog heart
Example of an adulticide used to treat Dirofilaria
Treatment of Diroflaria immitis (ZOONOTIC)
- Symptomatic (steroids, treatment of CHF)
- Adulticide therapy - melarsomine
- Microfilarial therapy - levamisole, ivermectin, milbemycin
Peak activity for ticks
Feeding season is March t June, peak activity is April, May
Bovine Babesiosis
B. divergens.
Pyreixa, Anaemia, Jaundice, HEMOGLOBINURIA, dEATH (24 hours if acute illness)
Diagnosis: Sample from ear/tail capillaries. = Ixodes ricinus
How does the tick vector differ between cow babesiosis and dog babesiosis
Bovine Babesiosis: B. divergins = Ixodes ricinus
Canine Babesiosis; B. gibsoni = Rhipicephalus sanguineus
ZOONOSIS; RARE; SPLENECTOMISED PEOPLE
Endemic stability
Calves <6 months are resistant to Babesiosis and develop immunity and asymptomatic carrier state = endemic stability.
DELIBERATELY GRAZE YOUNGSTOCK ON KNOWN BABESIA/ TICK PASTURE
Anaplasma phagocytophilia in large animals
Rickettsial parasite of leukocytes.
Tick borune fever.
Ixodes ricinus tickets.
Immune suppression - leukopenia, neutropenia, decreased phagocytosis.
Mostly asymptomatic but increased suspectibility to other dioseases. e.g. tick pyaemia, pneumonia.
Tick borne fever: fever and abortions in sheep and goats, milk drop and respiratory signs in cattle.
Louping ill virus
Only Flavivirus endemic to UK.
Upland areas Scotland, Wales, NW and SW England.
Sheep: Pyrexia and Paresis = Neuro signs.
Equine Infectious Anaemia
Horse flies and Satable flies.
In utero or saliva, nasal secretions, faeces, semen
LENTIVIRUS = Persistant infection, normally important to UK
NOTIFIABLE
Acute EIA
Can go un noticed 1-3 weeks Can also be fatal, Subsequent infection Chronic EIA: Signs include anaemia, thrombocytopenia, weight loss, dependent oedema
EIA diagnosis and control
EIA AB +VE culled (statutory)
No vaccine.
NB Ab may take 10-14 days to develop and serocovert after 45 days
Crimean-Congo Haemorrhagic Fever
Caused by Bunyacirus Wild and domestic animals Tick transmitted, Sub clinical in animals Zoonotic transmission.
