First detection of Pasteurella multocida type B:2 in Hungary associated with systemic pasteurellosis in backyard pigs

This is the first report of Pasteurella multocida type B in Hungarian pigs. This disease was observed in backyard-raised pigs in three households within a small area. Neither the source of the infection nor the epidemiological connection between any of the premises could be determined. The most consistent lesion was dark red discolouration of the skin of the ventral neck and brisket, with accompanying oedema and haemorrhages. The morbidity was low and lethality relatively high, with three dead (50%) and two euthanised (33%) out of six affected animals. A total of three isolates of P. multocida (P55, P56 and P57) were cultured from these cases and examined in detail. These were identified as P. multocida ssp. multocida biovar 3. All were toxA negative and belonged to serotype B:2. Multilocus sequence typing was used to assign these to a new sequence type (ST61) that is closely related to other haemorrhagic septicaemia causing strains of P. multocida regardless of the host. M13 polymerase chain reaction and virulence-associated gene typing also show that type B strains form a highly homogeneous, distinct phylogenic group within P. multocida.