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

PASTEURELLOSIS 199PASTEURELLOSISICD-10 A28.0Synonyms: Shipping fever, bovine respiratory disease complex, fibrinous pneumonia(cattle); pasteurella pneumonia (lambs); hemorrhagic septicemia (cattle,lambs); fowl cholera; snuffles (rabbits).Etiology: The genus Pasteurella was reclassified on the basis of DNA:DNAhybridization in order to determine the genetic relationship of the different acceptedor proposed species (Mutters et al., 1985). Based on the results of that study, thegenus has been subdivided into 11 species. The species of interest here are:Pasteurella multocida, P. dagmatis sp. nov., P. canis sp. nov., and P. stomatis sp.nov. P. caballi, described more recently, should be added as well (Schater et al.,1989). P. haemolytica, an important pathogen for animals and, occasionally, forman, is more related to the genus Actinobacillus and might receive its own genericname in the future (Mutters et al., 1986). In addition, the DNA:DNA hybridizationbetween strains of biotype A and biotype T ranges only from 3% to 13%, dependingon the biotype used as the reference strain, and thus the two biotypes should beclassified as separate species (Bingham et al., 1990). The advantages of reclassificationare not yet evident in epidemiological research, diagnosis, and treatment.Pasteurellae are small, pleomorphic, nonmotile, gram-negative, bipolar staining,nonsporulating bacilli, with little resistance to physical and chemical agents.Subdivision of P. multocida and P. haemolytica into serotypes is important in theareas of epidemiology and control (vaccines). Subclassification of P. multocida intoserotypes is based on its capsular (A, B1, D, and E) and somatic (1–16) antigens;the latter can occur in different combinations. P. haemolytica has been subdividedinto two biotypes (A and T) and 15 serotypes.Geographic Distribution: P. multocida and P. haemolytica are distributedworldwide. The distribution of the other species is less well-known, but based ontheir reservoirs they can be assumed to exist on all continents.Occurrence in Man: Rare. It is not a reportable disease and its incidence is littleknown. According to laboratory records, 822 cases occurred in Great Britain from1956 to 1965. A special survey in the US revealed 316 cases caused by P. multocidafrom 1965 to 1968. Data on the occurrence of human pasteurellosis in other countriesare scarce. The disease caused by P. haemolytica is rare.Occurrence in Animals: Common in domestic and wild species of mammalsand birds.The Disease in Man: The principal etiologic agent of human pasteurellosis is P.multocida. The other species make a lesser contribution to human disease. Fifty-sixcultures from Göteborg University (Sweden), obtained from human cases of pasteurellosis,were reexamined. As a result, 26 strains were reclassified as P. multocidasubspecies multocida; 11 as P. multocida ssp. septica; 12 as P. canis; 4 as P.dagmatis, and 1 as P. stomatis. Two strains were provisionally classified, one as P.haemolytica biogroup 2 (T) and another as belonging to the group that cannot betyped (Bisgaard and Falsen, 1986). The main clinical symptoms of the disease con-