Salmonella Infections Other Than Typhoid Fever
These areas and for persons working with Tryphosa. A course of immunization consists of three subcutaneous injections of 0.5 ml. of vaccine at weekly intervals. Local discomfort and Typhoid Fever frequently follow the administration of the vaccine. The vaccine can also be inoculated intracutaneously in doses of 0.1 ml.; the frequency of systemic reactions is less after this method of immunization than after administration of vaccine subcutaneously, but the local pain and tenderness may be severe and as uncomfortable as with the subcutaneous injection. To maintain optimal immunity it is necessary, to repeat immunization with a booster injection of vaccine at intervals of one year.
The degree of immunity conferred by the typhoid vaccine is not strong and can be overcome by exposure to massive numbers of organisms. Patients with typhoid fever should remain in isolation during hospitalization. Persons known to be carriers should not be permitted to work as food handlers, and members of their househOlds should be immunized against the disease. Second attacks of typhoid fever have been observed, but, as a general' rule, one attack confers lifelong immunity.
Infection cannot always be sharply differentiated and sometimes overlap. Incidence and Prevalence. Salmonellae, with the exception of a few serotypes, is widespread among members of the animal kingdom in all parts of the world. Virtually all domestic and wild animal species have been shown to harbor these organisms, and infection rates range from 1 percent to more than 40 percent. For example, in certain studies, salmonellae have been isolated. from 41 percent of turkeys, 7 to 50 percent of swine, and 24 percent of apparently healthy cattle.
The true incidence of human salmonellosis is unknown, but it is probably much higher than the number of reported cases. Since 1963 the incidence of reported isolations of salmonellae from a man in the United States has remained relatively constant at about 20,000 per year. The incidence of asymptomatic human carriers of salmonellae in the general population has been estimated to be about 0.2 percent. The carrier state in the vast majority of these people is transient and probably represents the persistence of organisms in. the stools after an asymptomatic or mild intestinal infection.
The transient carrier state is more frequent in persons whose occupations pro-vide opportunity for contact with salmonellae in foods, such as professional food processors or abattoir workers, than in the general population. Epidemiology. Man almost always acquires Salmonella infection by the oral route. Any item of food or drink can be contaminated directly or indirectly with viable bacilli from infected animals or men and can serve as a source of infection.: Although the role Of human carriers in the spread of— salmonellosis must not be Minimized, the majority of infections of man in the United States are related to the enormous reservoirs of salmonellae in lower animals.
The greatest single source of human disease is poultry products, including chickens, turkeys, ducks, and eggs. Other animal meats, especially pork, beef, and lamb, also serve as sources of infection. Salmonellae on meats or other foods contaminated utensils, tables, and other items in the processing plant, market, or kitchen, and may be transferred from these items to previously uninfected foods. A significant proportion (1 to 58 percent) of raw meats purchased in retail markets is contaminated with salmonellae. Eggs or egg products are very common sources of Salmonella infection, The Bali ID47, PeNil on the external surface of the eggshell, between the shell and the shell membranes, or in yolks of eggs from hens with ovarian infection.
The incidence of infection of eggs is low, but pooling of large numbers for freezing or drying increases the possibility. contamination of large quantities of materials. Prepared food mixtures containing dried eggs have been implicated many times in outbreaks of Salmonella infection. Sterilization of contaminated foods is not always, achieved by cooking.
Salmonella Infections Other Than Typhoid Fever Definition
Salmonella infection may be asymptomatic or manifested as acute gastroenteritis, bacteremia, or paratyphoid fever. The clinical syndromes resulting from Salmonella