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

CAPNOCYTOPHAGA CANIMORSUS AND C. CYNODEGMI 147described in Australia of a 66-year-old woman with septicemia who was hospitalized48 hours after having been bitten by her dog. The patient presented with symptomsof septicemic shock, hemorrhagic eruption, and altered consciousness. She hadno prior illness that could have predisposed her to this syndrome. She died 16 hoursafter being admitted, despite having received intravenous antibiotic treatment(Clarke et al., 1992).A similar case occurred in Belgium in a 47-year-old woman without any historyof prior illness. She was admitted to the emergency room with septic shock five daysafter receiving a small lesion on the hand from her dog. C. canimorsus was isolatedfrom her blood. Despite intensive treatment, she developed multiple organic deficienciesand died 27 days after being admitted (Hantson et al., 1991).The clinical picture includes meningitis, endocarditis, septic arthritis, gangrene,disseminated intravascular coagulation, and keratitis. The literature records a total offive cases of ophthalmic infections due to cat scratches or close exposure to thisanimal. There was also one case attributed to a dog (Paton et al., 1988).Capnocytophaga cynodegmi causes infection in wounds inflicted by dogs. It doesnot produce systemic infection.C. canimorsus and C. cynodegmi are sensitive to various antibiotics, includingpenicillin, erythromycin, minocycline, and doxycycline. Penicillin G is usually preferredby doctors for wounds caused by dogs (Hicklin et al., 1987). It should be keptin mind that 3% to 23% of the gram-negative bacteria isolated from the oropharynxof dogs may be resistant to penicillin (Hsu and Finberg, 1989).The Disease in Animals: C. canimorsus and C. cynodegmi are normal componentsof the bacterial flora in the oropharynx of dogs, cats, sheep, and cattle. Theyare not pathogenic for these animal species.Source of Infection and Mode of Transmission: The reservoir of the infectionis dogs and cats. The source is the saliva of these animals and transmission iseffected by a bite.C. canimorsus was isolated from the nose and mouth of 4 out of 50 clinically normaldogs (8%). The agent was also isolated from dogs and cats whose bites causedinfection in man (Bailie et al., 1978; Chen and Fonseca, 1986; Martone et al., 1980;Carpenter et al., 1987). A broader study indicated that in a sample of 180 dogs, 24%were carriers of C. canimorsus and 11% were carriers of C. cynodegmi; in a sampleof 249 cats, 17% carried C. canimorsus and 8% carried C. cynodegmi in theirmouths. The agent was also isolated in a significant percentage of sheep and cattle(25% and 33%, respectively). In contrast, these agents could not be isolated from thenormal flora of man (Westwell et al., 1989).C. canimorsus is primarily an opportunistic pathogen that infects individualsweakened by concurrent diseases. Those who have had a splenectomy comprise ahigh-risk group. Asplenic individuals suffer deficient IgM and IgG production anddelayed macrophage mobilization. They also produce less tuftsin, a protein derivedfrom IgG that stimulates phagocytosis (August, 1988). Liver disease caused by alcoholismis another predisposing factor for the infection. Predisposition is associatedwith susceptibility to bacteremia (Kanagasundaram and Levy, 1979).Role of Animals in the Epidemiology of the Disease: This is a zoonosis inwhich dogs and, to a lesser extent, cats, play an essential role.