Clostridium

Clostridium spp.

Large Gram-positive obligate anaerobic spore-forming rods

Habitat of Clostridium spp.

Soil intestines feces water and decaying organic matter

Major virulence factor of pathogenic Clostridia

Exotoxins

Neurotoxic Clostridia cause disease by what mechanism?

Toxin production with minimal tissue invasion

Histotoxic Clostridia primarily affect which tissues? (3)

Muscle liver and intestines

Most toxic exotoxin known

Botulinum toxin

Unique appearance of C. tetani

Terminal endospore giving a drumstick appearance

Habitat of C. tetani and of which animals?

Soil and intestines of horses and ruminants

Most susceptible species to tetanus

Horses and humans

Species relatively resistant to tetanus

Dogs cats and chickens

Two toxins produced by C. tetani

Tetanospasmin and tetanolysin

Transmission of tetanus

Puncture wounds umbilical infections uterine infections

Condition required for tetanus spore germination

Anaerobic environment

How does tetanospasmin reach the CNS?

Intra-axonal transport

Tetanus causes what type of paralysis?

Spastic paralysis

Mechanism of tetanus paralysis

Blocks inhibitory neurotransmitter release

Classic equine tetanus signs

Prolapsed third eyelid erect ears stiff gait elevated tail head

Typical stance in tetanus

Sawhorse stance

Characteristic severe extension of head and neck in tetanus

Opisthotonus

Main cause of death in tetanus

Respiratory failure

Method of tetanus prevention

Toxoid vaccination

Botulism is usually caused by what?

Preformed toxin

Species highly susceptible to botulism

Humans , poultry, waterfowl, ruminants horses

Species relatively resistant to botulism

Pigs dogs cats

Botulism causes what type of paralysis?

Flaccid paralysis

Mechanism of botulinum toxin

Blocks acetylcholine release at the neuromuscular junction

Major source of botulism in animals

Contaminated feed containing preformed toxin

Main cause of death in botulism

Respiratory failure

Floppy baby syndrome

Infant botulism

Shaker foal syndrome

Toxicoinfectious botulism in foals

Limberneck

Type C botulism in poultry

Lamziekte (associated with what)

Botulism in cattle associated with phosphorus deficiency and pica

Characteristic sign of equine botulism

Inability to withdraw the tongue

Causative agent of blackleg

Clostridium chauvoei

Species affected by blackleg

Cattle sheep goats

Age group most affected by blackleg

Young cattle 6 months to 2 years

Where do blackleg spores germinate?

Damaged muscle

Major lesion of blackleg

Emphysematous necrotizing myositis

Characteristic feature of blackleg lesions

Gas bubbles with rancid odor

Blackleg in cattle is usually what type of infection?

Endogenous infection

Disease caused by C. septicum

Malignant edema

Typical source of malignant edema

Wound contamination

Major lesion of malignant edema

Necrotic cellulitis with edema

Key difference between malignant edema and blackleg

Little or no gas in malignant edema

Disease caused by C. novyi type B

Black disease

Predisposing factor for black disease

Liver fluke migration

Where do C. novyi spores remain dormant?

Liver

Trigger for black disease

Hepatic injury causing spore germination

Characteristic feature of black disease

Sudden death with hepatic necrosis

Disease caused by C. haemolyticum

Bacillary hemoglobinuria (red water disease)

Predisposing factor for bacillary hemoglobinuria

Liver fluke infection

Characteristic urine finding in bacillary hemoglobinuria

Hemoglobinuria producing port-wine colored urine

Major lesion of bacillary hemoglobinuria

Hepatic infarcts

Habitat of C. perfringens

Soil and intestinal tract

Major predisposing factor for enterotoxemia

High concentrate diet

Most important toxin produced by all C. perfringens types

Alpha toxin

Alpha toxin is what enzyme?

Phospholipase C

Alpha toxin damages which cells?

RBCs, leukocytes, endothelial cells, and platelets

Type A major toxins

Alpha toxin and enterotoxin

Yellow lamb disease is associated with which type?

Type A

Human diseases caused by Type A

Food poisoning and gas gangrene

Type B disease

Lamb dysentery (destroys the lining of the gut)

Type C major toxin

Beta toxin

Type C primarily affects which animals?

Neonatal lambs calves foals piglets and kids

Major lesion of Type C enterotoxemia

Necrohemorrhagic enteritis

Type C in poultry causes what disease?

Necrotic enteritis

Type D major toxin

Epsilon toxin

Type D nickname

Overeating disease

Type D nickname

Pulpy kidney disease

Animals commonly affected by Type D

Rapidly growing lambs

Organs targeted in Type D disease (3)

Intestines CNS and kidneys

Classic lesion in Type D disease

Pulpy kidney

Causative agent of Tyzzer's disease

Clostridium piliforme

Unique feature of C. piliforme

Intracellular bacterium that cannot be grown on artificial media

Age group affected by Tyzzer's disease in horses

Foals younger than 6 weeks

Major lesion in Tyzzer's disease

Extensive hepatic necrosis