Veterinary Preventive Medicine-II

CLINICAL MANIFESTATIONS

• The clinical signs have been grouped as
  • Respiratory form
  • Vulvo-vaginal form
  • Ocular form
  • Encephalomyelitic form
  • Abortive form

Respiratory form

• This form is characterized by mild to severe rise of temperature, depression of appetite, acceleration of respiration and dyspnoea.
• The nasal discharges are initially serous which later turn to mucopurulent. Whole of the upper respiratory tract show hyperemia, edema along with mucopurulent exudation causing dyspnoea.
• Affected cattle may exhibit open mouth breathing in severe cases. Animal may show signs of bronchitis and pneumonitis.
• The nasal mucosa is severely congested hence the disease is named as "Red nose”.
• The recovered cattle may remain as carrier and thus shed the virus for a considerable period.

Vulvo-vaginal form

• This form is characterized by sharp fall in milk yield and appearance of erythematous and pustular lesions on the vulvar and vaginal mucosa.
• There is swelling of vulva and frequent urination. There may be mucopurulent discharge from vulva and vagina.
• Animal is unable to put its tail in normal position after urination due to pain. The virus produces pustular balanoposthitis in bull.
• The semen of the affected bull become contaminated and thus pose problem in natural or artificial breeding

Ocular form

• This form may appear along with respiratory form. There is inflammation of the conjunctiva in addition to respiratory changes.
• But in some occasions severe conjunctivitis and ocular discharges may be noted without respiratory involvement.
• The ocular discharges vary from serous to purulent.
• Petechial hemorrhages may be noted on the conjunctiva and sometime corneal opacity may appear as main attribute of the disease.

 

Encephalomyelitic form

• The virus may produce severe encephalomyelitis syndrome in calf terminating to death.
• The signs of encephalomyelitis comprise of high rise of temperature, incoordination, tremor, circling, falling, coma and death.
• Death ensures within 4 days following appearance of neurological signs.

Abortive form

• The pregnant cattle may abort following infection. The abortion may supervene as “abortion storm”.
• Foetus died at 4 months of gestation and expelled. Foetus is autolysed in most cases.