Anaphylactoid reactions to Mellavax [Salmonella dublin vaccine] in calves

Mellavax (avirulent S. dublin vaccine) appears to cause an anaphylactoid reaction in a ratio of 1:28 000 doses sold. A clinical picture of respiratory embarrassment and pulmonary oedema occurs. Histamine, 5-HT and dopamine are implicated mediators released during the reaction but to a minor extent compared with prostaglandins, which appear to play a major role in calves. Sodium meclofenamate, aspirin and indomethacin protect calves during acute systemic anaphylaxis and should be used in addition to adrenalin..