Musculoskeletal Intro and Dogs

Mycotoxins can cause ___________ signs, in addition to musculoskeletal.

neurological/respiratory

If you suspect mycotoxin toxicity in an animal - what could you test to confirm diagnosis?

test the feed! for toxin using HPLC and/or mass spectroscopy

Concerning nervous system involvement, what are clinical signs associated with subacute toxicosis with alflatoxins?

ataxia, weakness, tremors, coma

T or F: Mycotoxins can cause coagulopathy and hepatotoxicity in a wide variety of animal species

true

How can aflatoxicosis be prevented?

avoid indigestion by removing the feed

(buy good quality feed)

What's the first step to treating aflatoxicosis?

remove affected feeds!

______________ is the infectious agent of Equine leukoencephalomalacia & Porcine pulmonary edema syndrome

Fumonisin

Is Fumonisin toxicosis of public health concern? if so, how do humans get it?

yes!

humans get it from ingestion of contaminated corn -- NOT from animal products

Dallisgrass seedheads can develop a fungal infection (Claviceps) that causes __________ in people/animals.

erogtism

What type of environment does ergot thrive in?

high humidity and high soil moisture

What are clinical signs of ergotism in cattle and horses?

- Hyperexcitability

- Uncontrollable muscular tremors

- Incoordination

- Falling when forced to exercise

- Inability to regain feet.

- Lameness: • Can be the first sign in cattle. May appear 2-6 weeks after initial ingestion

What are clinical signs of ergotism in pigs?

- reduced feed intake and reduced weight gain

- Necrosis of tips of ears or tails

- Sows may have lack of udder development with agalactia at parturition

__________ get nervous ergotism prone to injury due to hyperexcitability

horses

____________ usually recover from disease (ergotism) when they are removed from ergotized pastures unless there [was] trauma or they become recumbent and die of exposure or lack of water.

Cattle

Dallisgrass with fungus can cause ergotism (neurological signs) in what three species?

horses

cattle

pigs

How might ergotism be prevented?

remove affected feed

What are three mechanisms of infection of muscle?

• Penetrating wounds

• Extension from a contiguous site

• Hematogenous infection

What are four responses that muscle may have to injury/infection?

Suppurative

Granulomatous

Gangrenous/Necrosis

Necrotizing fasciitis

Corynebacterium pseudotuberculosis and Pasteurella multocida infections of muscle result in ______________ inflammation.

suppurative

Tuberculosis and Actinobacillus ligniersii infections of muscle result in ______________ inflammation.

granulomatous

Clostridium infections of muscle typically have what kind of response to injury?

gangrenous/necrotic

Streptococcus release a toxin that will damage muscle and the bacteria grows along the fascial planes - this response to injury is called what?

necrotizing fasciitis

Concerning bone remodeling: (fill in with cell type)

- ____________ arrange the proteins and initiate mineralization. they can become osteocytes

- _____________ originate from same myeloid progenitors as macrophages

Osteoblasts

Osteoclasts

Concerning the response of bone to injury, Staphylococcus and E. coli cause a ______________ inflammation

suppurative

Concerning the response of bone to injury, Tuberculosis causes a ______________ inflammation

granulomatous

Necrosis of bone may result in a ____________, a piece of dead bone tissue occurring within a diseased or injured bone

sequestrum

Within the joint capsule, the bone is covered by ___________ cartilage

hyaline

How do the chrondrocytes within the articular cartilage receive nutrition?

by diffusion through the collagen matrix from the synovial fluid

What is arthritis?

Inflammation of the joint capsule and articular cartilage

What is osteoarthritis?

inflammation of the bone, joint capsule,

and articular cartilage

What is osteomyelitis?

inflammation of bone or bone marrow, usually due to infection.

What is diskospondylitis?

Inflammation or infection of the intervertebral disk and the adjacent vertebral endplates

Arthritis results in _________ blood flow and capillary permeability, and recruitment of ____________ cells.

increased

inflammatory

Describe the appearance of an arthritic joint

• Hot, swollen, painful joint

• Edema of the synovial membrane

• Increased volume of joint fluid

T or F: The joint fluid in infected joints may be fibrinous, purulent, and/or seropurulent.

True!

What is the difference between non-erosive and erosive arthritis?

non-erosive: fibrinous arthritis

erosive: purulent or septic

erosive occurs when cartilage within the joint capsule is not replaced as quickly as it is being destroyed - the cartilage is "eroded" away

- Hematogenous spread - Typically acute - Typically affects multiple joints are characteristics of joint infections in _________ animals.

young

Chronic and single joint infections are characteristics of joint infections in __________ animals.

mature

T or F: the introduction of an implant (foreign body) for fracture repair can predispose bone to infection

True!

Concerning fracture repair with the use of implants - what bacteria is the most likely agent to cause a biofilm and subsequent osteomyelitis?

Staphylococcus aureus (from skin)

Coccidioides immitis produces a lesion at the end of long bones that mimics _______________

osteosarcoma

What kind of agent is Coccidioides immitis?

a dimorphic fungus

How can Coccidioides immitis infection of bone be diagnosed?

cytology or culture (but with caution - dimorphic fungi - inhalation)

What are possible clinical signs associated with diskospondylitis?

lower back pain

lameness

possible neurological signs

Diskospondylitis is typically caused by _____________ spread.

hematogenous

What are the most common infectious agents of diskospondylitis?

- staph & E. coli

Borrelia burgdorferi is a gram negative, ____________

spirochete (know dis)

How is Borrelia burgdorferi transmitted?

Ixodes ticks

attached for 24-48 hours

What kind of organism is Borrelia burgdorferi?

gram negative SPIROCHETE

What are the virulence factors of Borrelia burgdorferi?

Ability to vary surface antigens

bind complement

block generation of reactive oxygen species chemotaxis of neutrophils

Is Borrelia burgdorferi zoonotic?

oh yes

The following are disease features of what infection?

- Tickborne disease

- Spirochete

- Causes chronic infection if untreated

Borrelia burgdorferi (Lyme Disease)

What is the source/reservoir of Borrelia burgdorferi?

white-footed mouse

chipmunks

squirrels

What is a major risk factor for Borrelia burgdorferi infection?

exposure to ticks in an endemic area

What are some clinical signs of Borrelia burgdorferi infection?

- Estimated that only 10% of affected dogs show overt signs of illness.

- Clinical signs in dogs occur 2 to 5 months after a tick bite

- Lethargy

- Fever

- Anorexia

- Thrombocytopenia

- Lameness due to neutrophilic polyarthritis.

• swollen, warm, painful joints.

• Non-erosive arthritis

- Mild generalized peripheral lymphadenopathy

Borrelia burgdorferi infection of joints causes ____________ arthritis (erosive/non-erosive)

non-erosive

How do dogs whose kidneys have been infected with Borrelia burgdorferi appear clinically?

Dogs with Lyme nephritis may have a thin body condition, dehydration, and show evidence of peripheral edema, pleural effusion, or ascites.

Describe the pathogenesis of Borrelia burgdorferi infection in dogs

- Change outer surface proteins

- Bind complement (evades complement system for clearance)

- Block generation of reactive oxygen species and chemotaxis of neutrophils

What are four things that may help in diagnosing Borrelia burgdorferi infection?

- History

- Clinical signs

- Serology

- PCR

What should you keep in mind when interpreting serology results for suspected Borrelia burgdorferi infection?

• Positive serology does not equate with current Lyme disease - Test results must be interpreted in light of clinical findings.

T or F: In serology testing for Borrelia burgdorferi cross-reactivity with vaccine antibodies does not occur.

True!

T or F: PCR is insensitive to Borrelia burgdorferi infection due to presence of bacteria in low numbers

True!

What are the two main components of Borrelia burgdorferi infection treatment?

antimicrobial therapy

supportive care

What is the prognosis for Borrelia burgdorferi infection?

Generally good except when there is interstitial nephritis

How can Borrelia burgdorferi infection be prevented?

- Tick prevention

- Vaccination may be helpful

Briefly describe the lifecycle of Borrelia burgdorferi

Tick eggs hatch into spirochete-free larvae --> larvae feeds on first host --> infected host carries spirochete --> larva attain spirochete from infected host --> tick larva drops to ground and molts to nymph (with spirochete) --> nymph may then feed on incidental or dead end host (hooman or doggo)

Brucella spp. are gram ____________ coccobacilli and are _____________ aerobes.

negative

obligate

What is the habitat of Brucella spp.?

persists in the environment

Brucella spp. are ______________ intracellular bacteria

facultative

How is Brucella spp. transmitted?

direct contact

ingestion

inhalation

What allows Brucella spp. to survive in macrophages?

it inhibits phagolysosome fusion

Brucella spp. has smooth or rough LPS - which is more virulent?

smooth!

Which Brucella spp. infects goats and sheep?

Brucella melitensis (not in the US)

Which Brucella spp. infects cattle, bison, elk?

Brucella abortus

Which Brucella spp. primarily infects pigs?

Brucella suis

Which Brucella spp. primarily infects dogs?

Brucella canis

Which Brucella spp. infects sheep?

Brucella ovis

Which Brucellae have rough LPS?

B. canis

B. ovis

Which Brucellae have smooth LPS and are therefore more virulent?

B. melitensis

B. suis

What is the major virulence factor of Brucella spp?

LPS! smooth or rough (smooth is more virulent)

Once in its host, Brucella spp. survive in ___________ (cell type)

macrophages

Brucella spp. infection is primarily a _______ infection and primarily affects the _________________ system.

chronic

reticuloendothelial

Specifically, what are three aspects of the reticuloendothelial system that Brucella infects?

- Lymphatics

- Bone marrow

- Endothelial cells that line tissues (bone marrow, liver, spleen)

Brucelae is shed intermittently in _______,

milk

T or F: Brucella infection typically only causes abortion in a heifer's first pregnancy and subsequent pregnancies typically do not abort.

True!

T or F: Brucella is only shed in a heifer's first aborted pregnancy, it no longer sheds in subsequent calving.

False!

there is shedding of brucellae at parturition of subsequent pregnancies

Where can brucellae be found in bulls?

reproductive organs!

testes

epididymis

Transmission of Brucella spp. is largely through exposure of __________ surfaces.

mucosal

T or F: Brucella spp. can penetrate intact mucosal surfaces

True!

What protective measures should you take when handling a patient suspected of having brucellosis?

face shield

gloves

What are major sources of transmission of Brucella spp?

- Aborted fetus

- Placenta

- Post abortion uterine fluids

- Sexually transmitted

- Milk—calves, kids, lambs, humans

- Urine—B. canis

• Primates have a _________ placenta

• Carnivores have a _________ placenta

• Ruminants have a _________ placenta

discoid

zonary

cotyledonary

With porcine brucellosis, what sorta things do we see?

• Prolonged bacteremia

• Chronic inflammatory lesions in the reproductive organs

• Lesions in bones and joints

What musculoskeletal issue does porcine brucellosis involve?

• Lesions in bones and joints - Lameness

What form of LPS is involved in canine brucellosis? smooth or rough?

ruff! - jk, rough

With canine brucellosis, what sorta things do we see?

• Typically causes mild to asymptomatic infections

• Reproductive

• Diskospondylitis

• Uveitis

What sort of reproductive pathologies are seen in canine brucellosis?

- Abortion, decreased fertility, reduced litter size

- Orchitis

What musculoskeletal issue does canine brucellosis involve?

• Diskospondylitis

- May cause neurologic signs or lameness

What even is diskospondylitis?

Inflammation or infection of the intervertebral disk and the adjacent vertebral endplates

What is the gold standard diagnostic test for Brucellosis?

bacterial culture