Outbreaks of fowl cholera in Muscovy ducks (Cairina moschata) on a farm in Aomori Prefecture.

Abstract

Outbreaks of a subacute disease characterized by lameness, corneal turbidity, dysstasia and depression occurred in Muscovy ducks (Cairina moschata) on a farm in Aomori Prefecture in February and May 1991. Nine strains of Pasteurella multocida were isolated from 5 to 6 dead ducks, and 4 of 8 ducks with clinical signs. Serotypes of the isolates were identified as Heddleston's serotype 1, 10 or 12 and Namioka's serotypes 5:A, 8:A, 9:A or 9:UT. These isolates were highly susceptible to 12 antibiotics, although, some of them were considerably resistant to chloramphenicol. Mouse LD50 values of the 9 isolates ranged from 10(1.0) to 10(5.3). The most virulent strain for the mouse killed 2 to 4 ducks when inoculated intramuscularly at a concentration of 10(3.3). This is the first report of outbreaks of fowl cholera in Muscovy ducks infected with various serotypes strains of P. multocida in Japan.