Lymphoid Disease in Ruminants Flashcards Preview

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Flashcards in Lymphoid Disease in Ruminants Deck (24):
1

Caseous Lymphadenitis

Sheep & goats
Gram +ve facultative anaerobe & facultative intracellular bacillus
Corynebacterium pseudoteburculosis
(nitrate -/+ biotypes)
Nitrate +ve one is associated with ulcerative lymphangitis in horses & cattle

2

Caseous Lymphadenitis - pathogenesis

outer cell wall = lipid layer
Resists phagocytic killing
Phospholipase D - exotoxin, cytotoxin, partial hemolysin, causes local inflammation & necrosis
Causes lymphatic thrombosis
Penetrates the skin
Leukocytes phagocytose the bacteria (survive)
Go to lymph node & multiply
cells die, release, lymphogenous & hematogenous spread

3

Caseous Lymphadenitis - transmission

Need to have a contaminated environment (e.g. wounds after fighting or shearing, traumatized oral/mucous membranes)
can be aerosol - pulmonary abscessation

4

Caseous Lymphadenitis - in environment

Doesn't multiply in the environment but survives for weeks to months
e.g. shaded areas, wooded bedding

5

Caseous Lymphadenitis - prevalence

Prevalence increase with age
Clnical cases are sporadic
Subclinical common
goats >> sheep

6

Caseous Lymphadenitis - clinical signs

SUperficial lymph node abscesses in head & neck
Visceral lymph nodes - weight loss anorexia, depression
Sheep lamelated - goats pasty & green-y

7

Caseous Lymphadenitis - diagnosis

clinical signs, cytology & culture of abscesses
elisa, serology
(CBC unreliable)

8

Caseous Lymphadenitis - PM

Abcessed lymph nodes
Peripheral or visearl lymph nodes OR abscesses in lung parenchyma

9

Caseous Lymphadenitis - treatment

no a/b
drain abscesses, but may cause transmission
no yet reliable vaccine
irradicate infected animals

10

Leukosis

A. enzootic bovine leukosis or B. sporadic

11

Enzootic Leukosis bovine leukosis

bovine leukaemia virus
any tissue affected
once clinical, fatal

12

Enzootic Leukosis bovine leukosis

macrophages & lymphocytes in a pro-viral form
antibodies produced but not effective to the virus

13

Enzootic Leukosis bovine leukosis - Factors affecting prevalence

age
level of infection in the herd
status of the dam
genetics
concurrent disease or stress

14

Enzootic Leukosis bovine leukosis - transmission

mostly horizontal, blood

15

Enzootic Leukosis bovine leukosis - clin path

lymphocytosis in 30% of seropositives
Lymphoma is <5% of seropositives
Latent period

16

A. Enzootic Leukosis bovine leukosis 1. persistant lymphocytosis

Persistant lymphocytosis - sublicinical lymphoproliferative state (pre-lymphosarcoma) tumour associated antigen in the circulating cells

17

Enzootic Leukosis bovine leukosis 2. multi-centric lymphoma

greater than 2 years old, sporadically
depends on cli
Lymph node, retrobulbar, abomasal, heart, meninges, etc.

18

A. Enzootic Leukosis bovine leukosis 1. persistant lymphocytosis

CBC for cell count etc

19

Enzootic Leukosis bovine leukosis 2. multi-centric lymphoma

lymph nodes are unreliable (don't test those
Do a post mortem & serology)
Aged serology - high sensitivity/specificity, but you may get false negatives & false positives
Can use RAA/Virus isolation/PCR

20

Enzootic Leukosis bovine leukosis - control

Can attempt eradication for control

21

sporadic bovine leukosis (name 3)

Juvenile multi-centril lymphoma
Cutaneous lymphoma
Thymic lymphoma

22

Juvenile multi-centril lymphoma

Cavles under 6 months
sudden onset, rapid course of disease
weight loss, depression, lymphadenopathy or variable signs depending on organs
If bone marrow infiltrates - anemia leukaemia

23

Cutaneous lymphoma

Dermal lesions, back hind limbs & perineum
May become multi centric lymphoma
Occurs in animals 1-3 years old
lesions are 1-3 cm with a necrotic centre
May regress & reoccur

24

Thymic lymphoma

6 months to 2 years old
Clinical signs associated with a mediastinal mass
Venous obstruction edema, jugular distension, thoracic fluid --> interfere with ventilation