ch.37SmithContinued Flashcards
What near-terminal event has been reported in horses with the acute or chronic liver failure?
fulminant intravascula rhemolytic syndrome
In hemoytic syndrome in horses with liver failure what is the pathogenesis?
+/- rbc fragility
** copper does not play a role
What is seen at necropsy in horses with hemolytic syndrome?
Widespread hemorrhagic lesions that resemble those described for DIC
Congenital erythropoietic porphyria has been reported in what spp?
Holstein cattle
Congenital erythropoietic porphyria is commonly referred to as?
pink tooth
Clinical signs of congenital erythropoietic porphyria
slow growth rates in calves
photosensitization
exfoliation of nonpigmented skin when exposed to sunlight
reddish-brown teeth
modest anemia
congenital erythropoietic porphyria: how is the disorder inherited in cattle?
autosomal recessive
congenital erythropoietic porphyria: disease pathogenesis?
metabolic defect is a herediatry deficiency fo the enzyme uroporphyrinogen III syntehase (UROS) which catalyzes an esential setp in syntehsis of the porphyrin structure of hemoglobin
–> resluts in accumulation of urorophoryn and coproporphyrin which deposit in teh teeth, where they are concentrated in the dentin, bones and other tissues
The reduced IV red cell lie span seen in congenital erythropoietic porphyria is due to
high concentration of uroporphyrin and coproporphyrin with in the cells
congenital erythropoietic porphyria consequence of porphyrs
may induce hemolysis and ldeay red cell series maturation in the bone marrow
Is there treatment for congenital erythropoietic porphyria?
No, however these cattle do reasonable well if housed indoors out of direct sunlight
What is the principle differential for congenital erythropoietic porphyria?
chronic flourosis– also produces brown discoloration of the theeth
Porphyria has been reported in what other spp, that has no health effects but causes a reddish brown discoloration?
Swine
Animals may develop acquired toxic porphyrias, with what substances?
heavy metal poisonings– principally lead
Pathogenesis of lead in the development of porphyria?
- inhibit several key enzymes of heme synthesis
-inhibition of aminolevulinate dehydrase leads to accumulation of aminolevulinic acid & decreased aminolevulinate dehdyrase activity
Depression anemia can be caused by:
- deficiencies of vitamins and minerals essential for RBC production
- systemic disease processes that interfere with normal erythropoiesis
- processes that damage or displace normal bone marrow elements
List nutritional deficiency’s as causes of depression anemia
Iron deficiency
Copper deficiency
cobalt deficiency
vitamin B12 deficiency
Folic acid deficiency
List anemias of inflammatory disease (depression anemia)
chronic infection
chronic inflammation
fractures and severe trauma
neoplasia
List anemia seondary to organ dysfunction
chornic liver disease
chronic kidney disease
chronic GI disease
parasitism (trichostrongylosis)
List causes of bone marrow damage/dysplasia that cause depression anemia
myeloid and megakaryocytic bone marrow hypoplasia in Standardbred horses
Bracken fern poisoning
Congenital dyserythropoiesis and keratosis in polled Hereford calves
Trichloerthlene-extracted soybean meal toxicity
Myelophthisic disorders (myeloproliferative disease, lymphoma)
aplastic anemia
In neonates what is the major source of iron?
colostrum
**as well as soil, dam’s feces, and milk
A modest anemia is anticipated in what cattle?
veal calves
Iron deficiency anemia has been documented in which spp?
calves and piglest housed exclusively indoors or in hatches with no access to soil
What in the body, account sfor 2/3rds of the total iron reserves found in teh body?
circulating erythrocytes
Where is 1/3 of the iron stored in the body?
liver
spleen
bone marrow
With chornic blood loss anemia, iron depletion is first indcated by what source?
decreased marrow iron
– seen with Prussian blue stain for iron
When is the typical microcytic, hypochromic erythrocytes seen in what stage of iron deficiency anemia?
In the late stages
**dec PCV, hgb concen, MCV, MCHC
The observed red cell abnormalities (echinocytosis, keratocytosis, schistocytosis, acanthocytosis, ovalcotosis) seen with Fe deficiency anemia are thought to be associated with:
oxidative damage
What is the treatment of Fe def anemia?
Dep on the cause and corection or resolution fo hte process responsibel for chornic blood loss
Iron dextran intended for use in baby pigs can cause anaphylaxis in what spp?
horses and cattle
Copper deficiency can occur as a primary problem in what animals?
milk fed animals or
pastured animals in copper deficient areas
More commonly than primary copper deficiency, it occurs secondary to
-imbalances in other trace minerals (dietary molybdenum excess, sulfur content or zinc)
Copper is an essential cofactor for:
a wide variety of enzymatic reactions
Clinical signs of copper deficiency are most prominent in what age group?
young, growing animals
Clinical signs of copper deficiency
reduced growth rate
rough and depigmented hair
diarrhea
osteoporosis with spontaneous fractures and anemia
In lambs copper deficiency can cause what syndrome?
swayback or enzootic ataxia
What role does copper play in iron metabolism
-important in iron transport from gut to marrow
-incorporation of iron into the heme moiety
What mineral deficiency anemia closely resembles iron deficiency anemia?
microcytic , hypochromic anemia?
Copper deficiency anemia
If sideroblasts are seen on bone marrow biopsy, what do they mean?
Problem in the incorporation of iron into the erythrocyte hemoglobin rather than actual deficiency of iron
ie: copper deficiency
How is copper deficiency detected?
measuring serum copper as ceruloplasmin, erythrocyte superoxide dismutase or copper content of hair, liver or kidney
In ruminants and horses only deficiency of what vitamin can lead to the development of anemia?
Vitamin B12 and folate
Which vitamins play an essential role in DNA synthesis?
vitamin B12 and folate
In ruminants, what has vitamin B12 deficiency been associated with?
grazing cobalt deficient pastures
Anemia resulting from chronic inflammatory occurs because of what mechanisms
-chronic release of inflammatory mediators (Interleukins) and release of acute phase proteins from the liver
–>sequestering iron from the circulation into storage forms (primarily liver and bone)
Myeloid and megakaryocytic bone marrow hypoplasia has been reported in what spp?
8 standardbred horses– all sired from the same stallion
aplastic anemia is a stem cell disorder characterized by:
reduced bone marrow production of all blood components in the absence of ta primary disease process infiltrating the bone marrow or suppressing hematopoiesis
What is usually the first indicator of aplastic anemia?
hemorrhagic diathesis caused by thrombocytopenia
– manifested as epistaxis, mucosal petechiae, or prolonged hemorrhage after trauma or injections
The diagnosis of aplastic anemia is based upon?
peripheral pancytopenia
bone marrow hypoplasia with fatty replacement
What toxicosis in ruminants resembles clinical signs of aplastic anemia?
bracken fern toxicosis
Clinical signs of bracken fern toxicosis
fever
melena
epistaxis
hematuria
mucosal petechiae
hyphema
bleeding from eyes and vagina
What is the major toxic factor in bracken fern?
ptaquiloside
Paradoxical erythroid hypoplasia is caused by
use of recombinant human erythropoietin (rhEPO) in race horses
**treated with steroids and returned to racing
Absolute erythrocytosis (polycythemia) definition
caused by an increase derythropoiesis that creates a circulating erythrocyte mass above nromal for the species
What must be ruled out with suspicion of Absolute erythrocytosis ?
relative erythrocytosis– caused by hemoconcentration, endotoxemia or splenic contraction (horses)
Absolute erythrocytosis diagnosis is based on
persistently elevated PCV
hemoglobin
erythrocyte count w/o clinical evidence of shock or dehydration
** and without response to IV fluid therapy
all disorders characterized by Absolute erythrocytosis share clinical manifestations caused by:
expanded blood volume &
increased viscosity
Besides humans familial erythrocytosis is described in what spp?
cattle
Familial erythrocytosis is caused by
autonomous erythropoietin produciton without demonstrable lesion
What should be ruled out when considering congenital erythrocytosis as a diagnosis?
-chronic hypoxia (r/o by measuring arterial O2 concentration)
Define polycythemia vera
idiopathic myeloproliferative disorder characterized by excessive proliferation of erythroid, myeloid and megakaryocytic elements, without an increasein plasma erythropoietin
**rare in animals
In domestic animals, absolute erythrocytosis is usually secondary to
chronic disease that produce tissue hypoxia
-ie: residence at high altitude, congenital heart defects that produce right to left shunting, chronic pulmonary disease
The partial pressure of oxygen (Po2) in capillaries must be maintained close to what level to ensure adequate off-loading of oxygen to tissues?
40 mmHg
In regards to the effects of high altitude, which spp are most susceptible and resistant?
- Cattle- most susceptible (1800 m above sea level) & sheep
- Horses (>2200 m above sea level)
- Goats
Is RAO/equine asthma able to cause hypoxemia sufficient to induce erythrocytosis?
No
When erythrocytosis not a in response to an appropriate phsyiologic stimulus, what is the recommended treatment?
phlebotomy to keep PCV below 50%
**controls hypervolemia and blood hyperviscosity
At what level of PCV is oxygen carrying capacity impaired?
> 60%
What are the forms of bovine lymphoma:
- sporadic bovine lymphoma:
- calf or juvenile form
-thymic or adolescent form
-cutaneous form
Lymphoid tumor’s of cattle with sporadic bovine lymphoma are typically of what cell lineage?
B and T cell
The msot common form of lmypom ain cattle occurs when and is associate dwith?
-adult cattle >2 yrs of age
- assoc with bovine leukemia virus
What cell lineage are BLV associated lymphomas of adult cattle?
B-cell lineage
BLV is an oncogenic type C retrovirus classified in what genus, subfamily and family?
genus: Deltaretrovirus
subfamily: Orthoretrovirinae
family: Retroviridae
What is the prevalence of juvenile lymphoma?
unknown
**but its rare
Common clinical signs of juvenile lymphoma
enlarged nodes (smooth, not hot or painful)
bloat
dyspnea
–pale mm (anemia), tachycardia, tachypnea, hyperpnea, cough, harsh lung sounds, fever, ruminal tympany enlarged liver, ataxia diarrhea
Prognosis for calf or juvenile lymphoma?
rapidly progressive– usually fatal w/in 2 to 8 wks of onset
Is the juvenile form of lymphoma associated with BLV?
Does not appear to be associated
The thymic form of bovine lymphoma is rare and seen in what age group?
typically 6 to 24 months fo age
C/S of thymic lymphoma
**signs of space occyping lesions in the neck
brisket enlargement
pitting edema
loss in bbody condition
rumen tympany
dysphagia
+/- bloat
With thymic lymphoma, what lymph nodes tend to be enlarged?
enalrge dsuperficial cervical and prescapular nodes
Why is fever a common clinical finding in bovids with thymic lymphoma?
unknown
– tumor necrosis, inflammatory medaitors, and/or secondary resp infections
Thymic lymphoma is often fatal because of:
bloat
Is thymic lymphoma associated with BLV?
No
Bovine immunodeficiency virus has been associated with what condition?
a lymphoproliferative condition associated with hemonode enlargement and some generalized lymphadenopathy
BIV belonges to what genus,subfamily, family?
genus: Lentivurs
subfamiliy: Orthoretrovirinae
family: Retroviridae
BIV infected calves develop what C/S
enlarged superficial nodes (hemonodes)– cervical region anterior and dorsal to the prescapular lymph node , over the spine of the scapula, in the paralumbar fossa and dorsal to the sub iliac (prefemoral) lymph node
What is the most common neoplastic disease of cattle?
adult (enzootic) form of lymphoma caused by BLV infection
A 2007 USDA national Animal Health Monitoring System study estimated that what percentage of dairy herds are infected with BLV?
84%
BLV forms of transmission
Horizontal: transfer of blood form an infected cattle to susceptible
Iatrogenic (needles, ear tatto pliers, etc.)
Tabanids (horse flies)
+/-nasal secretions
vertical transmission (dam to fetus)
Colostrum contains BLV
Can BLV be spread through nasal secretions?
Thought to be considered possible
What are factors that are considered to be associated with high rates of BLV infection in herds?
-Herd size positively correlated
-Close contact and heavy stocking/comingling
-presecne of persistent lymphocytosis
In regards to BLV, what is persistent lymphocytosis?
PL is an absolute lymphocyte count at least three standard deviations above the normally mean count that persists for at least 3 consecutive months
**increased the chances of horizontal transmission
BLV typical age of presentation
older than 4 years of age
** as young as 2 years
Common presenting clinical signs/history with cattle infected wiht BLV
-history of loss in condition
-abrupt drop in milk production (over a few days)-enlarged peripheral nodes
-exophthalmos
-partial to complete anorexia
-other signs: diarrhea, ataxia, paresis, ketosis, infertility
Whwat are common sites of lymphoid tumor predilection in adult lymphoma?
heart (r-atrium)
abomasum
uterus
kdiney
spinal cord (epidural sapce)
Other sites: retrobulbar space, rumen/reticulum
When is pitting edema seen with lymphoma?
When supramammary lymph nodes or cervical lymph nodes are involved
What peripheral lymph nodes are typically enlarged with lymphoma?
prescapular
subiliac
supramammary nodes
Which lymph nodes in cattle with lymphoma adominal tumors are involved?
internal iliac nodes
What percentage of cattle with BLV develop persistent lifelong lymphocytosis? and of which cell line?
approximately 30%
**mostly B cell lines
Melena in cases of BLV can be seen when?
When abomasal wall lymphoma ulceration with bleeding– melena, +/- anemia with GI hemorrhage
In a retrospective study on antemortem diagnosis for BLV, what were the findings?
lymph node needle biopsy to be 100% sensitivty while fine needle aspirate was only 41% senstive
What serologic tests are available for diagnosis of BLV?
agar gel immodiffusion (AGID)
enzyne linked immunosorbent assay (ELISA)
What is considered a cost effective tool in BLV control programs?
p24 antigen and whole BLV antibodies by ELISA compared to realtime PCR methods
Novel quantitative real-time PCR methods to measure proviral loads of known and novel BLV variants using what primers, are found to be more sensitive than some of the more traditionally real-time PCR methods and antibody based methods to detect BLV?
Coordination of Common Motifs (CoCoMo) primers
Are there vaccines for BLV that offer effective protection from BLV infection and control?
No
Is there evidence of BLV in semen?
no– transmission via insemination artificially has not been shown
What is the most common occurring hematopoietic neoplasia in horses?
lymphoma
What is one of the most common malignant neoplasms in the horse?
lymphoma
Clinical signs of lymphoma
nonspecific lethargy
weight loss
pyrexia
lymphadenopathy
–dep on location of tumor: diarrhea, colic, neuro signs, lameness, soteolysis, pathologic fractures
What are paraneoplastic conditions seen with lymphoma in horses?
pruritus and alopecia
hypercalcemia
IMHA
IMTP
In a retrospective study of classifying 203 cases of equine lymphoma, characterized lymphoma as:
multicentric (involving at least 2 organs excluding regional LN)
GI
cutaneous
bone marrow
nodal
splenic
hepatic
mediastinal
heart
ocular/orbital
CNS
oral cavity
nasal
In a retrospective study of classifying 203 cases of equine lymphoma, what were the most common anatomic locations identified?
Multicentric (83%)
cutaneous (19%)
Gastrointestinal (11%)
What is the diagnostic sample of choice for lymphoma?
biopsy of affected lymph node or organ
Morphologically lymphocytes are classified as small cell type if?
their nuclear diameters are 1.5 times the diameter of erythrocytes or less
Morphologically lymphocytes are classified as large if?
their nuclei average 2 times or more the diameter of erythrocytes
Small cell lymphoma is classified under what conditions?
if 60% or more small cells
Large cell lymphoma is classified under what conditions?
if 60% or more large cells
What has been identified as the most common subtype of lymphoma in the horse?
T cell rich B cell lymphoma
Immunohistochemical classification to determine the cell lineage is performed using monoclonal antibodies such as, which for B cell lymphomas and which for T cell lymphomas?
B cell lymphomas: CD79a, CD20
T cell lymphomas: CD3, CD8
Define multicentric lymphoma
lymphoma that involves two organ systems, excluding the regional lymph nodes, or involves multiple lymph nodes at distant anatomic locations
In which location of the gastrointestinal tract, where does lymphoma most commonly occur?
within the small intestine
What neoplasia is the most common in the intestinal tract in horses?
lymphoma
What breed is intestinal neoplasia most common?
Arabians with intestinal lymphoma
Lymphoma of the gastrointestinal tract, arised from where?
lymphocytes of the lamina propria of the intestinal tract–> results in diffuse or segmental thickening, focal masses or scattered crater-like ulcers with raised margins on the intestinal wall
Clinical signs associated with intestinal lymphoma
hypoalbuminemia– PLE
weight loss
edema
abdominal effusion
mild recurrent colic
diarrhea
Alimentary or intesitnal lymphoma glucose or xylose absorption tests?
frequently abnormal, indicating small intestine malabsorption
Results of abdominocentesis in alimentary lymphoma?
abdominal fluid was diagnostic in 38% of cases
What is the prevalence of mediastinal lymphoma?
varies from 4.5 to 29 % of all forms of lymphoma
What is the predominant subtyp eof cutaneous lymphoma?
T cell rich, large B cell (TCRBCL)
Is it alright to leave cutaneous lymphoma untreated?
risk of cutaneous lymphoma metastasizing ot internal organs or result in paraneoplsatic syndromes
Define angiotrophic lymphoma
lymphoma of the small blood vessels that spares the surroundign tissues
Define angiotrophic lymphoma
lymphoma of the small blood vessels that spares the surrounding tissues
Define leukemia
rare neoplasia co the hematopoietic sys that originates form the bone marrow (primary leukemia)
Characeristics of Luekoemic leukemia
increase in cell numbers in peripheral blood
define subluekemia leukemia
an increase in abnormal blast cells in blood, with a total whit ecell count w/in reference range or low
aleukemic leukemia characteristics
presence of abnormal cells in the bone marrow but not in peripheral blood
What is a consistent finign on bloodwork with leukemia in horses?
hyperproteinemia– due to hyperlgobulinemia
Define myeloma
neoplastic proliferation of plasma cells that primarily originates in the bone marrow but may have an extramedullary source
Define extramedullary plasmacytoma
accumulation of neoplastic plasma cells outside the marrow
Plasmacytomas can form in several organs and tissues, including the skin. what are the most commone extraosseous sites in horses?
lymph nodes
kidneys
spleen
liver
In secretory myelomas, neoplastic plasma cells are responsible for overproduction of what?
monoclonal Ig called M protein or paraprotein
Why are multiple bone marrow aspirates required for diagnosis of plasmacytosis?
because plasma cells are sparse in normal bone marrow
Define lymphangioma
tumor that originates from lymphatic vessels
**rare in hroses
What is the etiologic agent of anthrax?
Bacillus anthracis
Bacillus anthracis characteristics
large, rectangular shaped gram pos rod
In the vegetative form, Bacillus anthracis is most commonly found in
tissues of ifnected animals
When does Bacillus anthracis produces spores?
Under nutritionally limiting circumstances–> facilitating survial in harsh enviornmental conditions, cinldugin ehat, dryign and chemical tratments
**oxygen depdent process
Bacillus anthracis: entry into mammalian hosts can occur through which routes:
inhalation
ingestion
cutaneous routes
Bacillus anthracis: what is the most common route of entry in animal species?
ingestion
Can omnivores and carnivores become infected with Bacillus anthracis after eating meat form infected animals?
Yes
**less susceptible
Bacillus anthracis: what are the key plasmid encoded virulence factors that enables its survival in the host?
polyD-glutamic acid capsule necoded by pXO1
3 component toxicin encoded by pXO2
Besides the plasmid encoded virulence factors, what helps Bacillus anthracis evade the host’s immune system?
capsule
Bacillus anthracis: pathogenesis at the cellular level:
-lethal factor and edema toxin bind to protective antigen component on host cells
PA oligomerized ot induce endocytosis
-PA creates a stable pore LF and EF enter cytoplasma
–> both toxins interfere with cell signal transduction pathways–> dsuprte innate immuen cell functions, block inflamm cyotkine responses
Bacillus anthracis lethal factor and edema factor bind what to form lethal toxin and edema toxin?
protective antigen (PA)
**on host cells
In the United States Bacillus anthracis occurs frequently ine stbalished “zones” of which states?
Texas
Montana
Minnesota
North and South Dakota
What are environmental factors that are favorable to maintaining anthrax spores?
-soils with elevated pH
-hihg concentrations of selceted cations (Ca, MN)
_rich in organic material
What weather changes typically precede an outbreak of anthrax?
droughts followed by heavy rainfall or flooding
or earth disturbing activities like excavations
Bacillus anthracis outbreaks usually occur during what times of year?
During the warmer months of the year
Bacillus anthracis Transmission can occur via
access to blood or tissues form ifnected animals
bites from blood sucking insects (contirbutes in an outbreak)
wildlife carcasses
Bacillus anthracis animal susbceptibility to infection is dependent on
individual animal spp and route of infection
Which spp are most susceptible to peracute infections of Bacillus anthracis?
Ruminants: cattle, sheep, goats
Bacillus anthracis forms seen in horses?
- acute intestinal form: colic, diarrhea, cyanosis, fever and depression followed by fatal septicemia
- localized form: massive edema in neck region, progress to dependent edema involving thorax, abdomen, prepuce or mammary gland
Which spp is less susceptible to anthrax?
Swine
Necropsy of animals who died of anthrax
-bloody exudates from body orifices (that does not clot)
-incomplete rigor mortis
-rapid autolysis
-spleen: back berry jam consistency
Definitive diagnosis of Bacillus anthracis is base don:
microscopic exam of blood or tissue smears (collected w/in 24 hours of death)
bact cultures
what are samples that can be collected in cases where anthrax is suspected, without contaminated the environment (minimally)?
-unclotted blood collected form superficial veins
-ocular fluid collected in a sterile syringe using a large guage needle
-removal of an intact eye
Gram stains of Bacillus anthracis
large, gram positive, sqaured ended rods found singly or in chains of two to four cells
What stain confirms Bacillus anthracis capsule
polychrome methylene blue (m”faydean) stain
Appearance of typical Bacillus anthracis colonies in culture media
large, gray-white in color, have a rough, dry texture and usu non hemolytic
What is the appearance of gram stains of young Bacillus anthracis colonies?
long chains (10 or more cells) of large, square ended, gram-positive rods
**appearance of a row of “railway boxcars”
Verification of Bacillus anthracis isolates is done by
lack of motility
capsule production on specialized media
lysis of specific bacteriophage (gammaphage)
confirmatory PCR for toxin and capsule genes
Field isolates of Bacillus anthracis are usually susceptible to which antibiotics?
penicillin
tetracycline
What is critical in controlling anthrax outbreaks?
carcass management
-not opened
-burn or deep burial
prophylactic vaccination for prevention of Bacillus anthracis is usualy performed when?
annually 4 weeks before turning animals onto pastures where outbreaks have occurred
Preventative measures for Bacillus anthracis
-ensuring pastures of good quality– grazing close to soil is avoided to minimize exposure to spores
- avoid rough feed– reduce traumatic mucosal surfaces
-**do not recommend use of lime or other calcium containing products that alkalinize the soil
- avoid grazing animals on pastures altogether
What form of anthrax is common in humans?
cutaneous form
*inhalational is rare d/t high LD50 req for infection
Lyme’s disease causative agent
Borrelia burgdorferi
Borrelia burgdorferi ntramission
ticks belonging to Ixodes ricinus complex
based on geographic location within the US, what ticks transmit Borrelia burgdorferi
east coast: ixodes scapularis most common vector
West coast: ixodes pacificu (western black legged tick)
Ixodes scapularis larval ticks princpally acquire Borrelia burgdorferi spirochete from what animL?
Peromycus leucopus, the white footed mouse
What life stage of the Ixodes tick are the major transmitters of Borrelia burgdorferi to humans and animals?
nymphal stages
What are likely the enzootic reservoirs of Borrelia burgdorferi for Ixodes pacfiicus?
California kangarooo rate, Dipodomys californicus
Duskey footed wood rate, Neotoma fusicipes
What are the most common clinical signs of Borrelia burgdorferi in horses?
lameness and hyperestehsia
Diagnosis of recent or active Borrelia infection has been based on
high ELISA titers
psoitve Western blot
PCR
Because of similar vectors, what other organism can cause infection in horses with Borrelia burgdorferi?
Anaplasma phagocytophyllum
**Ixodes ticks
what are proposed antimicrobial agents for Borrelia burgdorferi
tetracycline
doxycyline
ceftiofur
**for 3 to 4 weeks
Francisella (Pasteurella) tularensis describe the organism
factulatative, intracellular, nonspore forming , gram netative coccobacillus
Francisella (Pasteurella) tularensis can survive longer than a year under what conditions?
frozen or in mud and water
What species are most commonly infected with Francisella (Pasteurella) tularensis
sheep, along with dogs, cats and humans
Humans experience what symptoms and how are they infected with Francisella (Pasteurella) tularensis?
plague like illness
bitten by infected ticks, fleas or insects when handling infected rabbits or hares
Francisella (Pasteurella) tularensis clinical signs
acute septicemia with localization and lymphadenopathy and granulomatous lesions in the organs (particularly liver and spleen)
otherwise nonsp signs: fever, anorexia, lethargy etc. etc.
Francisella (Pasteurella) tularensis Diagnosis
culture of organism from blood or organs
– BSL-3 level lab
–IFA testing, PCR or ELISA
fetal lesions from abortions caused by Francisella (Pasteurella) tularensis
multiofcal pinpoint necrosis of liver, spleen and lung
Differentials for Francisella (Pasteurella) tularensis include other bacteremias such as
Mannheimia (Pasteurella) haemolytica– sheep
Histophilus somni– cattle
mycoplasma mycoides subsp mycoides– goats
anthrax– all livestock
What lesions does Corynebacterium pseudotuberculosis cause and in what spp?
Sheep and goats: external/internal caseous lymphadenitis
Cattle: cutaneous excoriated granulomas and mastitic, visceral or mixed infections
Horses: external and internal abscesses
Corynebacterium pseudotuberculosis bacteria
gram positive, intracellular, nonmotile, pleomorphic, rod-shaped facultative anaerobe
What component of Corynebacterium pseudotuberculosis may account for its survival within macrophages?
high lipid content within the bacterial cell wall
**particularly corynomycolic acid
Strains of Corynebacterium pseudotuberculosis have been identified based on nitrate reduction and DNA fingerprinting techniques, which spp have which strains?
Small ruminants: nitrate negative
Horses: Nitrate positive
Cattle: Both
Is there natural cross spp transmission of Corynebacterium pseudotuberculosis between small ruminants and horses?
has not been reported
Corynebacterium pseudotuberculosis produces what exotoxins:
phospholipase D (PLD)
sphingomyelinase
inhibitory factor of staphylococcal Beta-hemolysin
hemolysis factor
dermanecrtoxins
mouse lethality toxins
Which exotoxins are important the pathogenesis of Corynebacterium pseudotuberculosis?
phospholipase D–> hydrolyzes lysophosphatidylcholine
sphingomyelinase–> hydrolyzes sphingomyelin
-enable degradation of the endothelial cell wall and INC vascular permeability
The SHI (synergistic hemolysis inhibition test) measures what?
IgG to phospholipase D exotoxin
–> synergism with R equi in lysing RBCs in agar forms the basis of the test
Corynebacterium pseudotuberculosis small ruminant C/S:
supuration and necrosis of lg superficial lymph nodes
Corynebacterium pseudotuberculosis where are external abscesses most commonly seen in sheep and goats?
mandibular
parotid
preformoral
prescapular
Differential diagnosis for Corynebacterium pseudotuberculosis in sheep and goats
abscesses caused by other organisms
trauma
seroma
hematoma
foreing body
injection reactoin
tumors
What is the most common presenting complaint for Corynebacterium pseudotuberculosis in sheep and goats?
chronic weight loss
What is the estimated prevalence of Corynebacterium pseudotuberculosis in large breeding operations in sheep and goats in endemic areas?
5% to 10%
What is the most common clinical form Corynebacterium pseudotuberculosis in cattle?
cutaneous excoriated granulomas
other forms: mastitis, visceral, mixed infections
Corynebacterium pseudotuberculosis lesions in cattle
ulcerative, exuding granulomatous lesions as large as 20 cm in diameter with necrotic areas that are easily surgically removed, leaving granulation tissue underneath
Do lesions caused by Corynebacterium pseudotuberculosis in cattle typically require treatment?
usually spontaneously heal in 2 to 4 weeks
Corynebacterium pseudotuberculosis ulcerative lymphangitis in horses differentials:
blutn trauma
fracture
foreign body
uncture wounds
nonseptic cellutis
staph cellulitis
other septic cellulitis
describe Corynebacterium pseudotuberculosis ulcerative lymphangitis lesions
severe cellulitis, lymphatics affected in one more more limbs , with multiple draining ulcerative lesions
Ulcer lymphangitis lesions often become chronic with what clinical signs?
limb edema
lameness
weakness
weight loss
What are the dfiferential diagnosis for Corynebacterium pseudotuberculosis in horses?
blunt trauma
fracture
foreign body
puncture wounds
nonseptic cellulitis
staphylococcal cellulites
other septic cellulitis
Corynebacterium pseudotuberculosis external abscessation is referred to as
pigeon fever
IN a large study of Corynebacterium pseudotuberculosis infection in horses, what percentage of horses developed internal abscesses (538 horses)
63% of horses
Corynebacterium pseudotuberculosis most common clinical signs of internal abscessation in horses
anorexia
fever
letarhgy
tachycardia
modest weight loss
Corynebacterium pseudotuberculosis most commonly affected anatomic location in horses caused internal abscessation?
liver
mesentary
mediastinum
lungs
kidneys
diaphragm
spleen
pericardium
blood
uterus
Corynebacterium pseudotuberculosis internal abscessation differential diagnosis
streptococcus
Actinomycoses
Staphylococcus
R equ in in foals
Coccidoides immitis
anaerobes
neoplasia
other causes of weight loss
Corynebacterium pseudotuberculosis presentation in humans?
occurs as a subacute to chornic lymphadenitis and pneumonia
Corynebacterium pseudotuberculosis human infections occur as a result from
consumption of unpasteurized infected milk or milk products
continued close contact with infected animals
handling contaminated equipment
exposure to wounds with exudates
Corynebacterium pseudotuberculosis spread from horses to humans?
Not reported
Corynebacterium pseudotuberculosis common clinical pathological abnormalities
anemia of chronic disease
inflammatory leukogram
What percentage of hosres with abdominal abscesses had abnormal peritoneal fluid?
93%
Of the percentage of horses with abdominal abscess caused by Corynebacterium pseudotuberculosis, with normal peritoneal fluid, where was the abscess located?
retroperitoneally (involving the kidneys)
Reasons for lack of culture results in Corynebacterium pseudotuberculosis peritoneal fluid
retroperitoneal locations
sequestered w/in a thick capsule
suppressed by local factors or nucleated cells
Bacterial culture is the preferred method of diagnosis for external infection, but horses without external abscesses what diagnostic test imay be useful?
SHI: synergistic hemolysis inhibition (SHI) test increased titers greater than 1280 are significantly assoc with internal infections
Corynebacterium pseudotuberculosis defintiive diagnosis
isolating the organism from abscesses or draining wounds
**grows well in blood agar 24 to 48 hours
When are Corynebacterium pseudotuberculosis infections most commonly seen in hroses
during fall and ealry winter months
**high incedence in September, October and November
What are insect vectors involved in transmission of Corynebacterium pseudotuberculosis in horses?
H. irritans (horn fly)
Stomoxys calcitrans
Musca domestica
**biting insects
Corynebacterium pseudotuberculosis disease transmission
biting insects (vector brone routes)
direct contac twith exduates or contaminated soil
Corynebacterium pseudotuberculosis incubation period in hroses
3 to 4 weeks
Risk factors for Corynebacterium pseudotuberculosis in hroses
young adult horses (<5 years of age)
horses housed otuside or with access to an outside paddock
Or in contact iwht other horses on pasture compared to stable dhroses
Corynebacterium pseudotuberculosis disease in sheep and goats, transmission
contact with exudate from draining abscess from animal to animal
or contaminated equipment
Corynebacterium pseudotuberculosis sheep that acquire the organism orally or from shearing wounds tend to have lesions lcoated whre?
parotid
submandibular
preformal
thoracic abscesses
IN sheep and goats Corynebacterium pseudotuberculosis incubation period?
variable, long
experimentally 2 weeks to sveral months
Corynebacterium pseudotuberculosis pathogenesis in horses
**speculative
-enters through skin or mucous membrane abrasion or wounds
-spread through lymphatics
-macrophages phagocytose and migrate to invasion site to engulf them
corynebacterium replicates in phagolysosome
Why does Corynebacterium pseudotuberculosis survive intracellularly?
-its high lipid ocntent (corynomycolic acid, resisting the action of lysosomal enzymes
What virulence factor of Corynebacterium pseudotuberculosis increased vascular permeability, causing spread of organism regionally and systemically
PLD toxins
phospholipase D
Important features to consider when treating external abscesses caused by Corynebacterium pseudotuberculosis
- allow the abscess to mature
- establish drainage
- collect and properly dispose of the infective exudate
- lavage the wound with an antiseptic solution
- apply insect repellant oinemtns and othe rmeasure of gly control
Corynebacterium pseudotuberculosis if antimicrobials are indicated (internal abscesses or ulcerative lymphangitis) what is necessary in their use?
long term (min 4 to 6 weeks)
Corynebacterium pseudotuberculosis antimocrbial susceptibliity
-TMS
-PPG
0mino
docy
0kpen
rfampin
Prognosis for horses with Corynebacterium pseudotuberculosis ulcerative lymphangitis and internal abscesses
guarded– improves if detected early an dlong-term therapy administered
Corynebacterium pseudotuberculosis treatment of choice in small ruminants
copmlete surgical removal of affected lymph nodes
Corynebacterium pseudotuberculosis small ruminants farms morbidity
can reach 100%
– depopulation mbeing the most ecnomic option
Corynebacterium pseudotuberculosis problem with enviornmental contamination
can survie in soila dn on formites
Corynebacterium pseudotuberculosis problem with enviornmental contamination
can survive in soil and on fomites
