The effect of various interventions during a typhoid epidemic. Results of a simulation study.

This paper presents an epidemiological model for typhoid fever epidemics or paratyphoid diseases with an enteric course, as well as a deterministic approach for the quantitative representation of this model. The model has been tested against one typhoid and two paratyphoid epidemics which occurred in the Federal Republic of Germany. It was possible to simulate the course of these epidemics with sufficient precision, and to obtain information on the effects of various interventions (e.

[Para-immunity after oral antigen administration].

The term "Paramunity" summarizes all non-pathogen specific mechanisms of the defence against infections in man and animal, such as phagocytosis, interference, antibiosis, activation of the lymphopoietic cell system and of lysosomal enzymes, stimulation of humoral factors etc. Examples for the induction of a paramunity are described. After an oral or inhalatory administration of polyvalent vaccines prepared from inactivated bacteria to mice, the rate of phagocytosis of the peritoneal or alveolar macrophages increased significantly.

Paramunity after oral immunization.

Previously, we have proposed the term of paramunity which represented the whole nonspecific defence reactions. Now, we experimentally have demonstrated the importance of an oral polybacterial vaccine in the local defence of the intestine against Salmonella or an enterovirus. The role of interferon was also discussed.

[An oral enteritis-vaccine composed of twelve heat-inactivated Enterobacteriaceae 3. Communication: studies on efficacy tests in mice protection tests (author's transl)].

The polyvalent vaccine consists of twelve heat-inactivated species of Enterobacteriaceae (six strains of Salmonellae, two strains of Shigellae, four strains of Dyspepsia coli). The above vaccine is administered orally (6) to man for prophylactic purposes against local infections. The present communication describes the efficacy results of the vaccine obtained for different parameters by the mouse protection test.

[An oral enteritis-vaccine composed of twelve heat inactivated Enterobacteriaceae. 2. Communication: the immunogenicity after treatment with simulated gastric and intestinal juice proved in an active mouse protection test (author's transl)].

In the first communication (3), we reported on the conception, the composition, and the efficacy of the polyvalent oral vaccine from 6 strains of salmonellae, 2 strains of shigellae, and 4 strains of dyspepsia coli. The inactivation took place at 100 degrees C/3 min. The question going to be answered in this communication was as follows: Does the immunogenicity of the vaccine decreased during the gastrointestinal passage under influence of acid and enzymes? We allowed the vaccine to react with simulated gastric juice and/or pepsin at pH = 3 and 37 C/60 min on the one hand and with simulated intestinal juice and/or pancreatin at pH = 7 and 37 degrees C/180 min on the other hand either individually or in combination.

[Animal experiments on combined local immunization against influenza (author's transl)].

Mice in ether narcosis were immunized 10 times by means of an inhalation spray with Begrivacs S (Behring-Werke) and then infected nasally with the virulent A/PR8 virus 7 to 12 days after the last immunization. A significant protection was achieved as gauged from the mortality rate. Furthermore, mice were nasally immunized with the polyvalent bacterial lysate vaccine IRS 19 (Sarbach, Chatillon) and subsequently infected nasally with the virulent influenza virus.

[An oral enteritis-vaccine composed of twelve heat inactivated Enterobacteriaceae. 1. Communication: Theoretical and epidemiological considerations (author's transl)].

The infectious diseases of the human intestinal tract which are caused by bacteria must be distinguished into two groups on account of their different pathogenesis: the cyclic infections (typhoid fever, parathyphoid fever) and the local infections (cholera, dysentery, Salmonella enteritis, dyspepsia coli infections). The local infections of the intestine do not cause a systemic but only a local immunity of the intestinal mucosa. It is necessary therefore to induce local immunity as active immunoprophylaxis by orally administering inactivated antigens.

Non-specific immunity after local immunization.

The most important advantage of local immunization is the non-specific effect. The active protection test in mice shows an immunity against oral infection with virulent Salmonella typhimurium bacteria after oral immunization with heterologous inactivated enterobacteria. We observed the same non-specific protection in a viral model.