COW POX

Etiology

  • Caused by a large virus of Vaccina subgroup (Hanson, 1970)

Mode of Transmission

  • Incidence is more due to obvious contact with milkman’s hand while milking.
  • Transmission is by direct contact with the affected cows.
  • Insect may also act as an agent of transmission of virus.
  • Milking machine may transfer the infection from cow to cow in a herd.
  • The virus enters through the small abrasions of the udder or teat.
  • The virus is prevalent in winter rather than summer months as the virus get inactivated in hot.

Pathogenesis

  • Incubation period: 3-7 days.
  • The typical pox lesions appear on the teat and udder.
  • The lesions comprise of erythema, followed by papules, vesicles, blister and pustules.
  • Pustules are taken over by scab.
  • The scab may detach during milking and ulcerative areas may develop.
  • The secondary bacterial infection or trauma may aggravate the lesions terminating to mastitis.

Clinical Findings

  • Temperature is mild.
  • Animal shows anorexia, suspended rumination and depression.
  • Udder is swollen, hot and sensitive.
  • Typical pock lesions appear on the teat and udder.
  • The lesions may be noted on the face of the calf.
  • In bulls, lesion appears on the scrotum and inside the thighs.
  • Lesions usually heal up within fortnight but in some cases, may persist for some months.
  • Due to recurrent attack, secondary mastitis may set up.

Lesions

  • On histo-pathological studies,the lesions show cellular proliferation and infiltrations.
  • The epithelial cells will contain eosinophilic inclusion bodies.

Diagnosis

  • It is based on characteristic skin lesions, spread of the disease in cattle.

Differential diagnosis

  • Foot and Mouth disease
  • In addition to teat and udder, lesions are also found in mouth and feet.
  • This causes high morbidity in adults and high mortality in new born calf.
  • Pseudo cow pox
  • Lesions are more numerous and less painful.
  • Scab formation is in an annular pattern.
  • This causes “milker’s modules” on the hands of the milker.
  • Udder impetigo
  • This is a bacterial disease, caused by Staphylococcus aureous.
  • Lesions are discrete and never become confluent.
  • Lesions are superficial, thin walled and the vesicles are surrounded by zone of erythrema.

Treatment

  • Symptomatic treatment is done.
  • Emollient ointments containing antiseptics or antibiotics can be used.
  • White field ointments containing salicylic and benzoic acid and “povidone iodine” ointment may be applied on the lesions.

Control

  • Isolation of the affected cattle from healthy one is to be made.
  • Hands of the milkers should be properly cleaned with the help of antiseptics.
  • Teats may be dipped into quarternary ammonium compound or potassium permanganate prior to milking.
  • Affected animals must be milked at last.