zoonoses and communicable diseases common to ... - PAHO/WHO

202 BACTERIOSESP. multocida is also responsible for cases of mastitis.SHEEP: P. haemolytica is the etiologic agent of two different clinical forms, pneumoniaand septicemia. Biotype A serotype 2 is the most prevalent agent of pasteurellapneumonia among lambs in Great Britain (Fraser et al., 1982). Pulmonarydisease in sheep follows a viral infection (P13). Although Pasteurella is a secondaryinvader, it is the predominant pathogen. Occurrence of the disease is sporadic orenzootic. The main symptoms are a purulent nasal discharge, cough, diarrhea, andgeneral malaise. Lesions consist of hemorrhagic areas in the lungs and petechiae inthe pericardium. Pasteurella septicemia is caused by biotype T of P. haemolyticaand appears in temperate climates in the fall, when the sheep’s diet is changed(Gillespie and Timoney, 1981). In Mexico, 860 pneumonic lungs were examined,and 120 isolates of P. haemolytica type A were obtained from them. The most commonserotypes were 1 (22%), 2 (16%), 5 (11%), and 9 (7%). Twenty-seven percentof the isolates could not be typed (Colin et al., 1987). P. haemolytica is the only etiologicagent of sporadic sheep mastitis in the western US, Australia, and Europe(Blood et al., 1979).SWINE: Pasteurellosis also appears in the form of pneumonia and, more rarely, assepticemia. Pasteurella may be a primary or secondary agent of pneumonia, particularlyas a complication of the mild form of classic swine plague (hog cholera) ormycoplasmal pneumonia. The anterior pulmonary lobes are the most affected, withhepatization and a sero-fibrinous exudate on the surface. Serotype 3:A of P. multocidais the most prevalent in chronic swine pneumonia (Pijoan et al., 1983). Studieshave revealed evidence of the etiologic role of toxigenic strains of P. multocidaserotype D in atrophic rhinitis. Bordetella bronchiseptica acting synergistically withtoxigenic strains of P. multocida probably causes this disease, the etiology of whichhas been the subject of much debate (Rutter, 1983).Atrophic rhinitis is characterized by atrophy of the nasal turbinate bones, sometimeswith distortion of the septum. Experiments have shown that the agents—B. bronchiseptica and toxigenic P. multocida—can cause the disease separately in1-week-old gnotobiotic suckling pigs. However, turbinate atrophy is more severeand may become complete when the animals are inoculated with both agents(Rhodes et al., 1987). Atrophic rhinitis could not be seen in some herds from whichonly B. bronchiseptica was isolated. The purified toxin of type D strains of P. multocida,inoculated intranasally, caused severe turbinate atrophy (Dominick andRimler, 1986).Various outbreaks of hemorrhagic septicemia caused by P. multocida 2:Bhave been reported in India. In one of these outbreaks, 40% of the herd died(Verma, 1988).RABBITS: Pasteurellosis is common in rabbit hutches. The most frequent clinicalmanifestation is coryza. As in other animal species, the disease appears under stressfulconditions. The principal symptoms are a serous or purulent exudate from thenose and sometimes from the eyes, sneezing, and coughing. The pathologicalprocess may spread to the lungs. Septicemia and death are not uncommon. Malesthat are kept together may show pasteurella-infected abscesses produced by bites.An atrophic rhinitis syndrome also occurs in rabbits. Autopsy of 52 adult rabbitsrevealed that 26 of them (50%) had turbinate atrophy. P. multocida and B. bron-