All Haemorrhagic septicaemia (HS) strains of Pasteurella multocida, fell into Roberts type I, P. multocida Roberts I: Carter B, the serotype is responsible for Asian HS. This study conducted to evaluate the validity of the mouse as model for HS in cattle, buffaloes, goats. A total of thirty six Swiss mice of both sexes divided into two main groups (infective and control) and each group subdivided into three groups (1st, 2nd, 3rd), each group subdivided into 2 subgroups (A, B). Each infective subgroups infected with different route (I.P and S.C) and different dose of the (Robert I :carter group B) strain as 104 cfu, 102 cfu and 50 cfu respectively for both routes. Many criteria (clinical sings, mortality, bacterial isolation from different organs, and gross pathological changes ) were used to describe infection in mice as a tool for further investigation in some large animals. The study showed that mice displayed fever, depression, anorexia, and other clinical signs 24hrs. before death which occurred between 24-72 hrs.
P. multocida: Robert I: carter : B was isolated from most organs of 1st and 2nd group infected with (104 and 102 cfu) but not isolated from the brain of third group infected with 50 cfu (I.P and S.C ) also from kidney and lung of S.C B3 of the infected mice, and from all organs of the third mouse of this subgroup.
Mice showed different gross pathological changes of internal organs and brain , these characterized by splenomegaly, hepatomegaly, petechial haemorrhage similar to that observed in cattle, buffaloes.
These results suggest that the mouse would seem to provide an ideal tool to study HS in cattle, buffalo.