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Infectious Lecture 4th Year 22-11-2016 Dr.Osamah Muwafk

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

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

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

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

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

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

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

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

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

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

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

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