Swine erysipelas - Pedigogy

Master Preventive Medicine – Notes, Case Studies and Practical Insights – with Lomash

Swine erysipelas:

Syn: Diamond skin disease

It is an infectious disease of pig characterized by the appearance of diamond shaped skin in acute form and suppurative and vegetative endocarditis in chronic form.
Word ‘erysipelas’ denotes ‘red skin’.

Etiology:

Erysipelothrix rhusiopathiae (insidiosa)
Gram +ve bacillus
Bacilli are slender, straight or slightly curved rods measuring 0.2-0.4 µm x 0.8-0.25 µm
Organism are non-motile, non-capsulated and non-acid fast.
Organism is relatively resistant to drying and may remain alive for several months in animal tissues, decaying carcasses, dried blood or fish meal.
22 serotypes are present, out of which serotypes 1 and 2 are commonly isolated from clinical erysipelas, 69 strains from tonsil of healthy pigs.

Epidemiology:

Disease is worldwide in distribution.
It is disease of economic importance throughout Europe, Asia, Australia, and America.
The domestic pig is the primary reservoir of E. rhusiopathiae, and probably 30–50% of conventional swine are carriers
Swine older than 3 months and younger than 3 years of age are most likely to develop clinical disease.
Erysipelas occurs in swine, lambs and turkeys.
Many healthy carrier pigs disseminate the organism in their feces and oronasal secretions.
Contaminated soil probably does not remain infective for more than 35 days.
Swine erysipelas can have highly variable morbidity and mortality rates, with morbidity often high (40-100%) and mortality ranging from 0-100%, depending on herd susceptibility, the causative bacterial strain, and the age of the animals.
Unvaccinated herds or those with poor hygiene and sanitation may experience higher morbidity and mortality rates.

Transmission:

Infection occurs mainly through ingestion of infected food and water.
Natural infection takes place from infected skin wounds.
Experimental infection is possible by inoculation of organism through scarified skin
Biting flies may introduce the disease.
Man is also susceptible and got public health importance. Veterinarians are exposed to infection when vaccinating with virulent culture.

Pathogenesis:

Clinical Findings:

Incubation period ranges from 3 to 5 days. Disease can be divided as acute, sub-acute and chronic.

Sudden death of animal without any prior signs.
High rise of temperature (104-108°F) and signs of chilling.
Animals isolate themselves from rest of animals and remain in lateral recumbency.
Stiffy gait and animals get up with difficulty.
Partial or complete loss of appetite, suspended bowel movement and hard feces.

Abortion may take place followed by infertility problem.
Conjunctivitis and vomiting
Cutaneous lesion develops as a characteristic sign. It is known as diamond skin lesion which appears 24 hours following the onset of signs.
Skin lesion appear as small slightly pink to dark purple areas which are raised and firm to touch.
In acute fatal cases, extensive dark purplish discoloration occurs over the belly, ears, tail, throat, neck and posterior aspect of thighs.

PM Findings:

Characteristic rhomboid urticarial lesion (diamond skin lesion) appears on affected pig.
Hyperemia, intravascular fibrin coagulation or thrombosis in smaller vessel of dermis and hypodermis.
Bacterial emboli are present within the vessels of the skin, spleen, liver, kidney, loose alveolar tissue of the dermis and hypodermis.
Cauliflower-like growth on the valves of heart known as vegetative endocarditis seen in chronic cases. Infarction of kidney and spleen

Venous congestion of lungs with edema.
Joints shows clear, amber to straw colored fluid. Capsular ligaments are thickened.
Ankylosis of joints may be evident.

Diagnosis:

Based on history: sudden death of pigs with no premonitory signs.
Based on clinical findings; skin lesion in different parts of body, dry feces followed by diarrhea.
Based on PM findings
Isolation of organism through bacterial culture. Organism can be cultured from heart, spleen, liver, kidney, lungs and joints.
Animal inoculation test: Pigeons may be inoculated with visceral organs suspension. Infected pigeons will die in 3-5 days.
Serological test: ELISA, Gel diffusion precipitation test, agglutination test

Differential Diagnosis:

Treatment:

Penicillin is the drug of choice. Massive dose of penicillin @ 50,000 IU per kg b.wt. may be required for effective response.
Tetracycline @500 mg/gallon may be added in drinking water on herd basis.
Drugs like lincomycin and tylosin can also be used.
Corticosteroid (betamethasone) may be tried to relieve arthritis lesion.
Anti-serum may be used @5-10 ml, SC for pig weighing less than 50 lbs.; 20-40 ml SC for pig weighing more than 100 lbs.

Control Measures:

Pigs should be raised with adhering husbandry practices. Care should be given in housing, feeding, watering, etc.
Recently purchased stock should be kept in isolation from rest for at least a month with adequate monitoring.
House and premises should be strictly disinfected following an outbreak. Disinfectants like phenol, alkali, hypochlorite and quaternary ammonium compounds are effective.
Chronically affected carrier pigs should be excluded from the farm.
Pasture should be kept vacated following outbreak for a month or so.
Dead carcass should be burnt properly.
Pigs are vaccinated with attenuated vaccine @6-10 weeks. Second booster dose is given 2-4 weeks later after first vaccination.