By Dr.Hirani Jamatia
INTRODUCTION:
Swine Erysipelas also commonly known as Diamond skin disease is an infectious disease of pigs of all ages. It occurs worldwide and commensals in a wide variety of vertebrate and invertebrate species.
ETIOLOGY:
The disease is caused by gram positive bacillus Erysipelothrix rhusiopathiae. Pig is the principal host of such infection. The organism can survive for 6 months in swine faeces at 12°C temperature. But can be readily killed in moist heat at a temperature of 60°C for 15 minutes.
SOURCE OF INFECTION:
Tonsil and lymphoid tissues of nearly 30-50% healthy pigs may harbour the infection.
Organisms may be excreted by carrier animals through faeces.
Infected rodents may spread the infection.
Clinically acute cases may shed the organism through faeces, urine, saliva, nasal discharges and contaminate the nearby surroundings. The organism is known to multiply in alkaline soils.
PATHOGENESIS:
Contaminated environment, carrier animals
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Organism ingested
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Enters through small intestine or tonsil
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Adhere to epithelium
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Into the blood stream
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Localization of infection in chronic form Septicaemia
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Immune complex
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Thrombosis
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Vascular damage Vascular damage
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Arthritis
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Endocarditis
CLINICAL FINDINGS:
The clinical forms are of acute, subacute and chronic form. These may occur alone or in combination.
1. Acute form:
Sudden death within 2-3 days in untreated cases
High temperature (104-108℉)
Pregnant sows may abort
Exhibit stiff gait and reluctant to move
Urticarial skin lesions may develop
‘Diamond shaped’ raised skin lesion appears 24 hours following the onset of signs (pathognomonic lesion)
2. Subacute form
Less severe than acute form and occasionally skin lesions may appear.
3. Chronic form
Arthritis is most common sign
Hock, stifle, knee and elbow joints become stiff and enlarged with locomotor disturbances
Endocarditis may occur.
POST MORTEM FINDINGS:
In acute cases, skin lesions, enlarged and congested lymph nodes, splenomegaly and hepatomegaly, oedematous and congested lungs, petechial haemorrhage on kidney and heart may be seen.
In chronic cases, proliferative and granular cauliflower like growths on the heart valves, embolism and infarction may develop. Arthritis and ankylosis of joints may also be evident.
DIAGNOSIS:
• Based on clinical signs and symptoms
Characteristic diamond skin lesion in acute cases and endocarditis in chronic cases are pathognomonic lesions.
• Post mortem lesions
• Isolation of organism from blood culture of infected pigs.
• Serological diagnosis is of limited application. Tests cannot be reliable for diagnosis but can be used to determine success of vaccination protocols.
• Differential diagnosis includes
a) Swine fever: Cauliflower lesion (vegetative form) on heart valves microscopically and diamond skin lesions do not occur. Highly fatal disease.
b) Salmonellosis: Gross skin discoloration and enteritis, isolation from faecal culture.
c) Glasser’s disease: severe painful dyspnoea, serositis, meningitis
PREVENTION :
Vaccination at the age of 6 to 10 weeks is advisable to control disease outbreaks. Booster vaccine must be given 2-4 weeks after the first vaccine. It must be taken into consideration that vaccine is not administered in pigs undergoing antibiotic therapy because antibiotics can interfere with the immune response.
TREATMENT:
Penicillin is the drug of choice for Erysipelas. Penicillin dose @ 50,000IU per kg body weight is effective. Tetracycline @500mg/ gallon of drinking water can be given on herd basis.
CONTROL MEASURES IN CASE OF OUTBREAK:
• Good management practices must be followed.
• The farm premises must be regularly cleaned and disinfected with common disinfectants like phenol, hypochlorite etc. The infected dead carcasses must be disposed off properly.
• Carrier pigs must be eliminated from the farm.
• The farm must be vacated for a month before bringing in new stock.
• Routine vaccination of healthy pigs must be carried out for next stock.
CONCLUSION:
There are several reports of seasonal outbreaks of swine erysipelas in organised as well as unorganised farms in the north-eastern and southern regions of the country. Swine erysipelas is of zoonotic importance as occupational disease in man. Most commonly presents three forms of infection – localised cutaneous form known as erysipeloid, generalised cutaneous form and a systemic septicaemic form. Herd immunization and preventive control measures are the most effective way to contain the spread of infection.
REFERENCES:
A textbook of Preventive Medicine by Amalendu Chakrabarti
