Infectious Lecture 4th Year 22-11-2016 Dr.Osamah Muwafk
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Tuberculosis Associated With Mycobacterium Bovis
ETIOLOGY:
1. Mycobacterium bovis
2. Occurrence in all species, including humans, and age groups
are susceptible to M. bovis
3. cattle, goats, and pigs most susceptible
4. sheep and horses showing a high natural resistance
5. Infected cattle are the main source of infection for other
cattle
6. Methods of transmission by inhalation or ingestion
7. The survival of the organism in the environment is influenced
by temperature, moisture, exposure to the desiccating effect
of sunlight, and ultraviolet light
8. Conceder an important zoonotic disease
PATHOGENESIS:
1. The primary complex consists of the lesion at the point of
entry and in the local lymph node
2. Calcification of the lesions commences about 2 weeks later
3. Post-primary dissemination an acute miliary tuberculosis
occure
4. discrete nodular lesions in various organs
CLINICAL FINDINGS:
1) progressive emaciation
2) A capricious appetite
3) Fluctuating temperature
4) The hair coat may be rough or sleek
5) Pulmonary involvement is characterized by a chronic cough
Infectious Lecture 4th Year 22-11-2016 Dr.Osamah Muwafk
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6) Mastitis
7) In horses the commonest syndrome is painful osteomyelitis
causes stiffness of the neck and inability to eat off the ground
caused by involvement of the cervical vertebrae
8) Sheep and goats bronchopneumonia is the commonest form
CLINICAL PATHOLOGY:
1. Tuberculin test (Single intradermal (SID) test, Short thermal
test, Stormont test)
NECROPSY FINDINGS:
1) Tuberculous granulomas may be found in any of the lymph
nodes, but particularly in bronchial, retropharyngeal, and
mediastinal nodes
2) miliary tuberculosis with small, transparent, shot-like lesions
in many organs
deferential diagnosis:
1. Lung abscess due to aspiration pneumonia
2. Pleurisy and pericarditis following traumatic reticulitis
3. Chronic contagious bovine pleuropneumonia
4. Upper respiratory disease
5. Actinobacillosis
6. Bovine leukosis
7. Lymphadenopathy
8. Other causes of mastitis
CONTROL:
1. Test and slaughter policy
Infectious Lecture 4th Year 22-11-2016 Dr.Osamah Muwafk
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PARATUBERCULOSIS (JOHNE'S DISEASE)
Etiology:
Mycobacterium avium subspecies paratuberculosis (Map)
Epidemiology
1. Occurs in cattle, sheep, and goats.
2. High prevalence of infection in cattle population and among
herds.
3. Incidence of clinical disease in herds about 1 % annually.
4. Transmitted by fecal-oral route.
5. Prenatal infection occurs.
6. Infection occurs soon after birth.
7. Long incubation period
8. is of great public health significance
PATHOGENESIS
1. Following oral ingestion
2. the organism localizes in the mucosa of the small intestine,
its associated lymph nodes and, to a lesser extent, in the
tonsils and suprapharyngeal lymph nodes.
3. The primary site of bacterial multiplication is the terminal
part of the small intestine and the large intestine.
4. The organism is phagocytosed by macrophages
5. macrophages proliferate in large numbers and infiltrate the
intestinal submucosa
6. results in decreased absorption, chronic diarrhea, and
resulting malabsorption.
7. There is a reduction in protein absorption and leakage of
protein into the lumen of the jejunum
Infectious Lecture 4th Year 22-11-2016 Dr.Osamah Muwafk
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Clinical signs
A. Cattle
1) Chronic progressive intractable diarrhea
2) emaciation in adult cattle extending over several
weeks and months
B. Sheep
1) Chronic wasting disease of adult sheep
2) diarrhea not a distinct clinical finding.
3) Common cause of emaciation in ewes
Clinical pathology
1) Culture feces
2) Serological tests (ELISA, AGID, C F)
Lesions
1) Chronic granulomatous enteritis
Differential diagnosis
1) Diarrhea in adult cattle
1. Intestinal parasitism (ostertagiasis)
2. Salmonellosis
3. Secondary copper deficiency
2) Emaciation in adult cattle
1. Chronic traumatic reticuloperitonitis
2. Malnutrition
3. Pyelonephritis
4. Lymphosarcoma
5. Amyloidosis
3) Diarrhea and weight loss in sheep and goats
1. Gastrointestinal parasitism
Infectious Lecture 4th Year 22-11-2016 Dr.Osamah Muwafk
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4) Chronic weight loss in sheep and goats
1. Internal abscesses
2. Caseous lymphadenitis
3. Caprine arthritis-encephalitis
4. Ovine progressive pneumonia
5. Dental disease
ACTINOMYCOSIS (LUMPY JAW):
ETIOLOGY:
- Actinomyces bovis
EPIDEMIOLOGY:
1. The disease is sporadic but common in cattle.
2. Actinomyces bovis is a common inhabitant of the bovine
mouth
3. infection is presumed to occur through wounds to the
buccal mucosa caused by sharp pieces of feed or foreign
material
PATHOGENESIS:
1. In the jawbones a rarefying osteomyelitis is produced.
2. The lesion is characteristically granulomatous.
3. The effects on the animal are purely physical
CLINICAL FINDINGS
Cattle
1. Actinomycosis of the jaw commences as a painless, bony
swelling
Infectious Lecture 4th Year 22-11-2016 Dr.Osamah Muwafk
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2. which appears on the mandible or maxilla, usually at the
level of the central molar teeth.
3. The enlargement may be diffuse or discrete
4. The swellings are very hard, immovable
5. They usually break through the skin and discharge through
one or more openings.
6. The discharge of pus is small in amount and consists of
sticky, honey-like fluid containing minute, hard, yellow
white granules
TREATMENT AND CONTROL
1. Treatment is with surgical debridement and antibacterial
therapy,
particularly
iodides
as
detailed
under
actinobacillosis.
2. Additional treatment recorded as being effective includes
isoniazid given orally at the rate of 10-20 mg/kg body
weight daily for about 30 days
Infectious Lecture 4th Year 22-11-2016 Dr.Osamah Muwafk
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ACTINOBACILLOSIS (WOODEN TONGUE):
ETIOLOGY:
Actinobacillus ligllieresii
Occurrence:
1. The disease in cattle is worldwide in distribution
2. usually of sporadic occurrence on individual farms
3. it is a normal inhabitant of the oral cavity and rumen of
ruminants
4. infection occurs through ulcerating or penetrating lesions to
the sulcus of the tongue,
PATHOGENESIS:
1. Local infection by the organism causes an acute
inflammatory reaction
2. subsequent development of granulomatous lesions
3. necrosis and suppuration occur, often with the discharge of
pus to the exterior.
4. Spread to regional lymph nodes is usual
Clinical findings:
1. animal being unable to eat for a period of about 48 hours.
2. There is excessive salivation and gentle chewing of the
tongue
3. On palpation the tongue is swollen and hard, particularly at
the base
4. Enlargement of the retropharyngeal nodes causes interference
with swallowing, and loud snoring respiration.
5. Cutaneous actinobacillosis is also recorded
Infectious Lecture 4th Year 22-11-2016 Dr.Osamah Muwafk
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6. In sheep the tongue is not usually affected. Lesions up to 8
cm in diameter occur on the lower jaw, face, and nose, or in
the skin folds from the lower jaw to the sternum
CLINICAL PATHOLOGY
1. Purulent discharges commonly contain 'sulfur' bodies which
are granular in nature and, on microscopic examination,
consist of club-like rosettes with a central mass of bacteria.
DIFFERENTIAL DIAGNOSIS
1) Foreign bodies in the mouth
2) Rabies
3) Esophageal obstruction
4) Tuberculosis
5) Cutaneous lymphosarcoma
TREATMENT
1) Potassium iodide, 6-10 g/day for 7-10 days, given orally as a
drench to cattle
2) Sodium iodide (1 g/12 kg body weight) can be given
intravenously as a 10% solution in one dose to both cattle and
sheep
3) two further treatments at 10- to 14-day intervals are required
for bony lesions
Infectious Lecture 4th Year 22-11-2016 Dr.Osamah Muwafk
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ORAL AND LARYNGEAL NECROBACILLOSIS
Oral necrobacillosis: infections of the mouth and larynx with
Fusobacterium necrophorum. It includes calf diphtheria, in which
the lesions are largely confined to the larynx and pharynx, and
necrotic stomatitis, in which the lesions are restricted to the oral
cavity
ETIOLOGY:
1) F. necrophorum
2) The causative bacterium is a common inhabitant of the
environment of cattle
3) under unsanitary conditions the infection may be spread on
dirty milk pails and feeding troughs
4) It is a common disease in feedlots in yearling cattle
5) necrotic stomatitis occurring mainly in calves 2 weeks to 3
months of age
6) laryngeal infections commonly affect older calves and
yearlings
7) Risk factors : intercurrent disease, nutritional deficiency and
unsanitary conditions
PATHOGENESIS:
1) F. necrophorum is a normal in habitant of the oral cavity
2) inflammation and necrosis occurre following injury of the
mucosa of the oral cavity, pharynx, and larynx
3) Edema and inflammation of the mucosa of the larynx results
in varying degrees of closure of the rima glottides , and
inspiratory dyspnea and stridor.
4) The presence of the lesion causes discomfort, painful
swallowing and toxemia.
Infectious Lecture 4th Year 22-11-2016 Dr.Osamah Muwafk
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5) Extension of the lesion to the arytenoid carti1ages will result
in laryngeal chondritis
6) Involvement of the cartilage will usually result in delayed
healing or failure to recover completely
CLINICAL FINDINGS:
1. painful cough
2. severe inspiratory dyspnea
3. salivation
4. painful swallowing movements
5. complete anorexia
6. severe depression
7. high temperature (41°C; 106°F)
8. The breath has a most foul rancid smell
9. pharyngeal region may be swollen and painful on external
palpation
CLINICAL PATHOLOGY:
- Bacteriological examination of swabs from lesions may assist
in confirming the diagnosis.
Necropsy findings:
1. Severe swelling, due to edema and inflammation of the
tissues surrounding
2. the ulcer, is accompanied by the presence of large masses of
caseous material
DIFFERENTIAL DIAGNOSIS:
1. Neoplasms of the larynx
2. Traumatic pharyngitis
Infectious Lecture 4th Year 22-11-2016 Dr.Osamah Muwafk
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3. Foreign bodies
TREATMENT:
1) application of a solution of tincture of iodine
2) oral administration of sulfamethazine at a dose of 150 mg/kg
BW daily for 3-S days.
3) parenteral penicillin or broad-spectrum antimicrobials
4) Corticosteroids may be a beneficial adjunctive therapy,
especially to reduce the edema