Black Leg, Leptospirosis, Brucellosis Flashcards by Danica Polbos

The causative agent of Blackleg is:

Clostridium chauvoei

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Blackleg primarily affects:

Young calves and lambs

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The primary route of infection in cattle with Blackleg is:

Ingestion of spores

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In sheep, Blackleg infection is most often associated with:

Wound infections

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The pathogenesis of Blackleg involves:
a) Toxin production and muscle necrosis
b) Septicemia and organ failure
c) Immune-mediated destruction of muscle tissue
d) Viral replication in muscle cells

Toxin production and muscle necrosis

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A characteristic clinical sign of Blackleg is:

a) Severe diarrhea
b) Coughing and respiratory distress
c) Crepitant swelling in muscles
d) Anorexia and weight loss

Crepitant swelling in muscles

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The lesions associated with Blackleg are characterized by:

a) Abscess formation in the liver
b) Hemorrhagic and emphysematous myositis
c) Ulceration of the intestinal lining
d) Inflammation of the joints

Hemorrhagic and emphysematous myositis

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What contributes to the anaerobic environment conducive to C. chauvoei growth in muscle tissue?

Recent injury or bruising

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The main virulence factor of C. chauvoei is:

Toxin A (CctA)

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The definitive diagnosis of Blackleg is made by:

a) Clinical signs and history
b) Culture and identification of C. chauvoei
c) Serological testing
d) PCR assay

Culture and identification of C. chauvoei

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Which of the following is NOT a typical finding on post-mortem examination of a Blackleg case?

a) Dark red to black, dry and spongy muscles
b) Sweetish odor in affected muscles
c) Significant edema in affected muscles
d) Gas bubbles in affected muscles

Significant edema in affected muscles

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The most effective method for controlling Blackleg is:
a) Antibiotic treatment of affected animals
b) Vaccination
c) Proper disposal of carcasses
d) All of the above

All of the above

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The recommended vaccination protocol for calves against Blackleg involves:

Two doses, 4 weeks apart, followed by annual boosters

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In an outbreak of Blackleg, in addition to vaccination, what other measure can be taken to prevent new cases?

Prophylactic administration of penicillin

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Which animals are most susceptible to Blackleg?
a) Older, debilitated animals
b) Young, well-nourished animals
c) Pregnant animals
d) Lactating animals

Young, well-nourished animals

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Leptospirosis is caused by:
a) A virus
b) A bacterium (Leptospira)
c) A protozoan
d) A fungus

A bacterium (Leptospira)

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Leptospira organisms are characterized by their:
a) Rod shape
b) Corkscrew-like motility
c) Spore formation
d) Capsule production

Corkscrew-like motility

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Leptospirosis is a:
a) Non-zoonotic disease
b) Zoonotic disease
c) Vector-borne disease
d) Food-borne illness

Zoonotic disease

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Maintenance hosts for Leptospira are characterized by:

High prevalence of infection, mild clinical signs, and persistent shedding

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Incidental hosts for Leptospira are characterized by:

Severe clinical signs and short renal phase

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Transmission of Leptospirosis can occur through:

a) Contact with infected urine
b) Ingestion of contaminated water
c) Venereal transmission

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Leptospires typically enter the body through:

Mucous membranes or damaged skin

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The pathogenesis of Leptospirosis involves:
a) Bacterial replication in various tissues
b) Toxin production and organ damage
c) Immune complex formation
d) Both a and b

Both a and b

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Clinical signs of Leptospirosis can include:
a) Fever
b) Renal or hepatic damage
c) Uveitis
d) All of the above

All of the above

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A MAT titer of ≥ 800 in a suspected acute infection of Leptospirosis suggests:

Current or recent infection

Treatment for Leptospirosis in cattle often involves: a) Antiviral medications b) Antibiotics (e.g., streptomycin) c) Corticosteroids d) Supportive care only

Antibiotics (e.g., streptomycin)

The primary course of Leptospirosis vaccination in cattle typically consists of:

Two injections, 4 weeks apart, followed by annual boosters

Which of the following is NOT a recommended control measure for Leptospirosis? a) Vaccination of all susceptible animals b) Elimination of maintenance hosts c) Proper hygiene and sanitation d) Prompt treatment of infected animals

Elimination of maintenance hosts

This is a highly fatal disease of cattle characterized by emphysematous swelling of muscles without a history of wounds.

Blackleg

C.chauvoei is found naturally in _________ of animals.

intestinal tract

Cattle on a farm with recent excavations and flooding are dying suddenly with lameness and limb swelling. What disease is most likely?

Blackleg

In the proposed pathogenesis of blackleg, which tissue is the primary target for Clostridium chauvoei spores where they become dormant?

skeletal muscle

What is the primary virulence factor of Clostridium chauvoei?

Hemolysin - C. chauvoei is toxin A (CctA)

Cellular effects of CctA

Hemolysis, cytolysis

Cellular effects of DNase

DNA degradation

Cellular effects of Hyaluronidase

degradation of extracellular matrix

Major toxin produced by C. chauvoei resulting to decreased membrane rigidity and loss of cellular attachments

Neuraminidase

Where on the body do the characteristic edematous and crepitant swellings typically develop in cases of blackleg?

hip, shoulder, chest, back, neck, or elsewhere in the body

What are the key pathological findings in the skeletal muscles of animals with blackleg, particularly in the hindlimbs?

Classical necrohemorrhagic and emphysematous myositis

How does the swelling in blackleg appear at initial stage of the disease?

focal, hot, and painful

How does the swelling in blackleg appear at later stages of the disease?

enlarge, crepitation on palpation, skin becomes cold and insensitive

A rapidly fatal, febrile disease in well-nourished young cattle, particularly in beef breeds, with crepitant swellings of the large muscles suggests?

Blackleg

What is the appearance and odor of the affected muscles in blackleg, and what other characteristic findings are present?

Color: dark red to black Texture: dry and spongy Odor: Sweetish odor

What are the components of the multivalent vaccine used to protect cattle and sheep against blackleg and other related clostridial infections?

Clostridium chauvoei, Clostridium septicum, Clostridium novyi

How and when should calves be vaccinated for blackleg?

2 months old (Twice vaccine) - 4 weeks apart, followed by annual boosters

During a blackleg outbreak, what measures should be taken with susceptible cattle to control the spread of the disease?

1. Vaccination 2. Penicillin for 14 days

What is the recommended vaccination schedule for naive ewes against blackleg, including the timing of the initial doses and annual boosters?

Twice vaccination - 2nd dose before lambing, followed by annual boosters

The common source of Leptospira infection in humans:

dogs, rats

What are the typical characteristics of leptospirosis infection in maintenance hosts?

1. High prevalence of infection 2. Low antibody responses 3. Few organisms in tissues 4. Mild acute clinical signs 5. Persistent infection in the kidneys and sometimes the genital tract

What are the typical characteristics of leptospirosis infection in incidental hosts?

1. Low prevalence of infection 2. Severe clinical signs 3. Short renal phase of infection 4. Marked antibody response 5. Larger numbers of organisms in tissues

Leptospira serovar with a maintenance host of dogs:

Canicola

Leptospira serovar with a maintenance host of pigs, cattle, opossums:

Pomona

Leptospira serovar with a maintenance host of cattle:

Hardjo

Leptospira serovar with a maintenance host of Rats

Icterohaemorrhagiae

Leptospira serovar with a maintenance host of raccoons, muskrats, skunks

Grippotyphosa

How is leptospirosis typically transmitted among maintenance hosts?

1. Direct contact with infected urine, placental fluids, milk 2. Venereal 2. Transplacental

What environmental conditions favor the survival of leptospires?

moisture and moderately warm temperatures

How many days will it take for leptospires to replicate in many tissues such as in liver, kidneys, lungs?

7-10 days

Which hosts do leptospires often remain in the renal tubules, genital tract, eyes even after recovery?

Maintenance hosts

In these hosts, leptospires remain in the tubules of the kidneys in short period of time and shed in the urine for a few days to several weeks:

Incidental hosts

Subclinical infections of Leptospirosis are common in?

Maintenance hosts

Describe the clinical findings of leptospirosis in incidental hosts:

Acute, systemic, often febrile illness characterized by renal or hepatic damage.

What MAT titer is considered indicative of leptospirosis in cattle?

≥800

Treatment for leptospirosis infection in cattle

Streptomycin/dihydrostreptomycin 25 mg/kg, IM

The cornerstone of leptospirosis prevention:

Vaccination with polyvalent inactivated vaccines.

T/F. Immunity to leptospirosis is assumed to be serovar specific.

True.

What is the recommended protocol for introducing replacement animals, including bulls, into a closed herd with no history of leptospirosis infection?

3 weeks isolation Streptomycin 25 mg/kg (Twice, 10-14 days apart)

Other names for Bovine brucellosis:

Contagious Abortion or Bang’s disease

How many Brucella abortus biotypes are present?

What are the principal symptoms of Brucella infection in female and male cattle?

Female - abortion Male - orchitis and bursitis

T/F. Brucella infection is rarely spread through sexual contact in cattle.

True.

Which group of cattle are more prone to being infected with bang's disease?

Sexually mature and pregnant cattle

Why does Brucella preferentially target the reproductive tract, particularly in cattle?

Due to erythritol sugar, generated within the fetal tissues of cattle, which stimulates the growth of Brucella organisms.

During which month of gestation are elevated erythritol levels in the placenta and fetal fluids considered a significant factor in Brucella-related abortions?

5th month

Give at least 4 consequences of Brucella infection:

1. abortion 2. stillbirths 3. retention of the placenta 4. weak calves

Abortion is a typical finding of bang's disease. Name 2 clinical outcomes of abortion:

1. Retention of the fetal membrane 2. endometritis

In cows infected with Brucella, after uterine involution is complete and shedding from the uterus ceases, where do foci of infection typically persist?

supramammary lymph nodes and in the udder

Standard diagnostic method for Brucella abortus

Agglutination tests