These Sources of Infection Are Also Important in the Perpetuation of Endemic Infection
Tisdale, W. A.: Spontaneous colon Endemic Infection in Laen-, NEC's cirrhosis. Gastroenterology, 40:141, 1961. Weinstein, L., and Klainer, A.S.: Management of emergencies: IV. Septic shock Pathogenesis and treatment. New Eng. J. Med., 274:950, 1966.
GHeGELLOSS Leighton E. Cluff
Definition. Shigellosis is an enteric infection with one of the species of Shigella bacilli, which may be asymptomatic or may cause dysentery. Bacillary dysentery is usually. Dysentery has been recognized for centuries. Association of the bacillus isolated from feces of patients with the disease was possible by the demonstration of rising titers of specific serum agglutinins in a significant proportion of patients. It has occasionally caused epidemic diseases in hospitals, nurseries, and schools. Currently, Shigella infection is responsible for a significant proportion of diarrheal dis-ease particularly among children and older persons living in crowded urban areas.
Over 40,000 cases were noted in 1960. Etiology. Strains of These are usually identified as serotypes of Shigella Dyson-time (Shiga), Shigella generic, Shigella body, and Shigella sonnei. Another group, formerly referred to as Shigella alkalescent, may also produce enteric infection in man, but biochemically and antigenically it is more closely related to coliform bacilli. The Shigella are gram-negative, slender, nonmotile, nonsporulating bacilli, which on. primary isolation resembles coccobacilli. Species and strains of Shigella can be identified by carbo-hydrate fermentation and antigenic analysis with specific antiserum.
Young children appear to be more susceptible than adults to bacillary dysentery, but the dis-ease is less common in the first six months of life than in older infants and children. Eighty percent of c.61Idren under nine years of age rizthceea' wren Shigella will develop dysentery, whereas only about 50 percent of infected older persons develop the illness. Under the age of 20 years the frequency of shigellosis' is in males is .greater than in females, but over the age of 20 years, the reverse is true. at all ages. be in winter, spring, or autumn.
Shigella may be found in the intestinal tracts of flies having contact with infected human feces, but the carriage of the bacilli on the insect's feet is probably how it may spread infection. In countries with a high standard of sanitation, flies play an inconsequential role in the transfer of infection. Inadequately washed hands or contaminated inanimate articles are the principal means of transmission. The seats of toilets may become contaminated during flushing and serve as a source of infection. or feces of infected persons. These sources of infection are also important in the perpetuation of endemic infection.
Secondary cases may result in the extension of the disease to other schools or institutions such as hospitals, or nurseries. Relapsing disease, reinfection, and chronic infection may enable the perpetuation of infection among patients in nursing homes and inmates of mental hospitals. Endemic and epidemic shigellosis is' commonly characterized by isolation of several different serologic types of Shigella. Major outbreaks caused by a single serotype are rare, but small outbreaks may be attributable to a single serologic type. Shigella dysenteriae (Shiga) is an uncommon cause of infection in Britain, Europe, and North America, but is responsible for a significant proportion of cases in Asia. Shigella sonnei is the prominent cause of bacillary dysentery in countries where personal contact and endemic infection, rather than poor sanitation and unhygienic conditions, are responsible for the spread of the disease.