Pathology and Microbiology of Tetanus

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Questions and Answers

What is the characteristic gross lesion of PM lesions?

A large tumor

A distinct ulcer

No characteristic gross lesion (correct)

A characteristic rash

What makes it very difficult to establish a diagnosis of tetanus?

Lack of symptoms

The presence of multiple symptoms

The presence of a clear rash

History and symptoms are unclear (correct)

What is the portal of entry for tetanus?

Through contaminated food

Through respiratory system

Through skin abrasions

Through puncture wounds (correct)

What is the name of the toxin that reaches the interspinal site and causes muscle spasms?

Tetanospasmin Signup and view all the answers

What is the result of tetanospasmin blocking the secretion of inhibitory neurotransmitters?

Muscle spasms Signup and view all the answers

What is the mode of transmission of Clostridium tetani?

Through wound contamination Signup and view all the answers

What is the ultimate outcome of tetanus if left untreated?

Asphyxiation Signup and view all the answers

Which of the following animals is most susceptible to tetanus?

Horses Signup and view all the answers

What is characteristic of focal necrosis of liver in systemic infection?

Diffuse purulent inflammation Signup and view all the answers

Which of the following is NOT a feature of microscopic lesions in medulla?

Tissue necrosis Signup and view all the answers

In which animals is abortion common due to this infection?

Cattle and sheep Signup and view all the answers

What is the characteristic feature of foetal liver in abortion?

Focal hepatic necrosis with stainable organisms Signup and view all the answers

What is the diagnosis of this infection based on?

All of the above Signup and view all the answers

What is enterotoxic colibacillosis caused due to?

Colonisation of Escherichia coli on the surface of intestinal cells and production of toxins Signup and view all the answers

Which age group is most affected by enterotoxic colibacillosis?

Young piglets, calves, and lambs during the first week of life Signup and view all the answers

What is a feature of enteroinvasive colibacillosis?

Less common in animals Signup and view all the answers

What is the primary function of the polysaccharide capsule in P. haemolytica?

To inhibit complement-mediated serum killing and phagocytosis Signup and view all the answers

Which of the following is a consequence of leukotoxin production by P. haemolytica?

Release of proteolytic enzymes and oxidant products Signup and view all the answers

What is the primary cause of death in animals infected with P. haemolytica?

Hypoxia and toxemia Signup and view all the answers

Which of the following is a characteristic clinical sign of pneumonic pasteurellosis?

Ghar-ghar sound on respiration Signup and view all the answers

What is the primary pathological finding in animals infected with P. haemolytica?

Widespread petechiae and ecchymoses on mucous and serous membranes Signup and view all the answers

Which of the following is a consequence of endotoxin production by P. haemolytica?

Increased production of cAMP and cGMP Signup and view all the answers

What is the primary histopathological finding in the lungs of animals infected with P. haemolytica?

Fibrinous or lobar pneumonia Signup and view all the answers

What is the common name for pneumonic pasteurellosis?

Shipping fever Signup and view all the answers

What is the primary mode of transmission of glanders in animals?

Through ingestion and inhalation of organisms Signup and view all the answers

What is the result of the septicaemic phase in glanders?

High temperature and acute inflammatory reaction Signup and view all the answers

What is the characteristic of glanders in stained smears?

Neutrophils undergo degeneration and karyorrhexis Signup and view all the answers

What is the name of the disease caused by Burkholderia mallei?

Glanders Signup and view all the answers

Which of the following is NOT a mode of transmission of glanders?

Vector transmission Signup and view all the answers

What is the outcome of glanders if left untreated?

Death due to anoxic anoxia Signup and view all the answers

What is the characteristic of cutaneous involvement in glanders?

Formation of nodules and ulcers in the skin Signup and view all the answers

Which of the following animals is highly susceptible to glanders?

Horses Signup and view all the answers

What is the characteristic microscopic feature of Actinobacillosis?

Presence of a colony of organisms surrounded by neutrophils and mononuclear cells Signup and view all the answers

What is the difference between Actinobacillosis and Actinomycosis in terms of microscopic features?

Actinobacillosis has more purulent exudate, whereas Actinomycosis has less purulent exudate Signup and view all the answers

What is the characteristic feature of the 'Sulfur granule' in Actinobacillosis?

It is a blue-stained colony of bacteria surrounded by a red irregular peripheral rim Signup and view all the answers

What is the material that should be collected for the diagnosis of Actinobacillosis?

Smears of pus from the deeper portion of the lesions, heat fixed, and pus in sterile tubes, small pieces of affected tissue in 10% formalin Signup and view all the answers

What is the primary method of diagnosis for Actinobacillosis?

Isolation of bacteria from the affected tissue Signup and view all the answers

What is the differential diagnosis for Actinobacillosis?

Actinomycosis, Nocardiosis, and Staphylococcal infections Signup and view all the answers

What is the characteristic feature of Actinomycosis?

Suppurative osteomyelitis of the mandible and miliary nodules in the lungs Signup and view all the answers

What is the common name for Actinomycosis?

Lumpy jaw Signup and view all the answers

Study Notes

PM Lesions

No characteristic gross lesion
No characteristic microscopic lesion

Tetanus

A bacterial disease of animals caused by the toxins of Clostridium tetani
Characterized by prolonged spasmodic contractions of muscles, stiffness, and immobilization
Also known as lock jaw
Horses are most susceptible, and cattle are the least susceptible
Etiology: Clostridium tetani, a gram-positive, anaerobe, rod-shaped bacterium that produces toxins
Spread:
- The portal of entry is usually through puncture wounds
- Wounds can be caused by nail-pricks, castration, docking, or shearing, or received during parturition
Pathogenesis:
- Sequel to a wound
- Growth of anaerobic Clostridium tetani
- Releases neurotoxins
- The toxin known as tetanospasmin reaches the interspinal site by entering the bloodstream and traveling along nerves to the central nervous system
- Blocks the secretion of inhibitory neurotransmitters, leading to tetanic spasm of voluntary muscles and ultimately, nerve block and paralysis
Death occurs from asphyxiation due to fixation of the muscles of respiration

Pathogenesis of Pneumonic Pasteurellosis

Complex and not clearly understood
Four virulence factors of P. haemolytica:
- Fimbriae
- A polysaccharide capsule
- Endotoxin (lipopolysaccharide)
- Leukotoxin
Capsule inhibits complement-mediated serum killing and phagocytosis and intracellular killing of the organism
Endotoxin can alter bovine leukocyte functions and is directly toxic to bovine endothelium
Leukotoxin is produced by all known serotypes and is highly toxic to bovine neutrophils and macrophages
When destroyed by leukotoxin, release of proteolytic enzymes, oxidant products, and basic proteins which degrade cellular membranes, increasing capillary permeability
Fluid accumulation in the interstitium of the alveolar wall, alveolar wall necrosis, and pulmonary edema
Death occurs as a result of hypoxia and toxemia

Clinical Signs of Pasteurellosis

High fever (105-107°F)
Oedema in the throat and brisket region
Dyspnoea
Ghar-ghar sound on respiration

Pathological Findings of Pasteurellosis

Widespread petechiae and ecchymoses on mucous and serous membranes
Oedema of the lungs and lymph nodes
Oedema of the subcutaneous tissue with gelatinous fluid
In a few animals, there are lesions of early pneumonia and haemorrhagic gastroenteritis

Microscopic Features of Actinobacillosis

Presence of colony of organisms
Palisade of Indian club-like structures surrounded by neutrophils, mononuclear cells, and lymphocytes
Such lesions are surrounded by fibrous tissue
Muscle tissue of the tongue is replaced by fibrous tissue

Diagnosis of Actinobacillosis

Symptoms and lesions
Isolation of bacteria
Demonstration of organisms/colony in tissue sections
Demonstration of rosettes and the absence of Gram-positive organisms
Differential diagnosis: actinomycosis, nocardiosis, and staphylococcal infections ("botryomycosis")

Actinomycosis

A disease of cattle, buffaloes, and camels caused by Actinomyces sp.
Characterized by suppurative osteomyelitis of the mandible and miliary nodules in the lungs
Also known as lumpy jaw

Microscopic Lesions of Actinomycosis

Medulla:
- Circumscribed mononuclear cells in perivascular areas
- No tissue necrosis
- Organisms are Gram-positive and demonstrated in tissue sections
- Micro abscess in the brain
Systemic infection:
- More common in monogastric animals
- Focal necrosis of the liver (characteristic) - Micro abscess in the liver
Abortion:
- Common in cattle and sheep
- Focal hepatic necrosis with stainable organisms seen in foetal liver

Colibacillosis

Three distinct pathogenetic mechanisms are identified in enteropathogenic Escherichia coli (E. coli)
Enterotoxic colibacillosis:
- Caused by colonization of E. coli on the surface of intestinal cells and production of toxins
- Most common in young piglets, calves, and lambs during the first week of life

Glanders

Synonym: Farcy, malleus
A contagious disease of horses, mules, and donkeys (solipeds), usually chronic in nature
Characterized by formation of nodules and ulcers of the upper air passages, lungs, and cutaneous tissue
Aetiology: Burkholderia (Pseudomonas) mallei (Actinobacillus mallei)
Incidence:
- Horses, mules, and donkeys are highly susceptible
- Man is moderately susceptible
- Sheep and goats may be infected
Transmission:
- Ingestion
- Inhalation
- Through skin invasion
Pathogenesis:
- Infection is by ingestion and inhalation of organisms
- Penetrating the pharyngeal and intestinal mucosa
- Entering the general circulation and reaching pulmonary capillaries
- Septicaemic phase with high temperature
- Forming emboli in the pulmonary capillaries
- Acute inflammatory reaction in the perialveolar and peribronchiolar area
- Serous exudate in the connective tissue

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Description

This quiz covers the diagnosis and characteristics of tetanus, a bacterial disease affecting animals, including its macroscopic and microscopic features.