"Approved"
on a methodical conference
department of infectious diseases and epidemiology
"
" __________ 2008
Protocol №
Сhief of dept, professor
V.D. Moskaliuk
METHODOLOGICAL INSTRUCTIONS
To a fifth year student of the Faculty of Medicine
On independent preparation for practical training
TOPIC: PREVENTION AND ANTI-EPIDEMIC MEASURES AGAINST
INTESTINAL INFECTIONS (TYPHOID FEVER, SHIGELLOSIS,
SALMONELLOSIS).
Subject:
Major:
Educational degree and qualification
degree:
Year of study:
Hours:
Epidemiology
Medicine
Specialist
5
2
Prepared by assistant professor
Sydorchuk A.S., MD.
1. Topic: Prevention and Anti-epidemic Measures against Intestinal
Infections.
2. Lesson duration: 2 hours
3. Aims of study:
3.1. Students must know:
- aetiology of typhoid fever, shigellosis, salmonellosis;
- social conditions that promote occurence and spreading of intestinal
infections;
- mechanisms and transmission ways of infection stimulus in case typhoid
fever, shigellosis, salmonellosis;
- sequence of epidemiologic inspection of the nidus;
- actions to eliminate epidemic nidus of typhoid fever, shigellosis,
salmonellosis according to the scheme: isolation forms (hospitalization)
of a patient, subsequent care of people who already had the illnesses,
disinfection methods and disinfectants, preventive measures for healthy
people (observation).
- rules of discharge of reconvalescents.
3.2. Students must be able to:
- draw up an epidemiological analysis;
- develop indications to conduct epidemiological inspection of the nidus;
- make a plan of anti-epidemic measures to destroy nidi of intestinal
infections;
- fill in medical documents of an epidemic inspection of nidus (emergency
information report, epidemiologic inspection card, control card of patient
under clinic observation);
3.3.Students must master the following practical skills:
- how to draw up an epidemiological anamnesis and analysis of the
information received;
- how to fill in document forms;
- how to do an inspection of the epidemiological nidus of intestinal
infections;
- how to make a plan of counteractions on the base of epidemiological
inspections of the nidus.
4. Students are advised to:
- pay special attention to specific features of epidemiological inspection of
nidi of infectious illnesses of infections.
- pay attention to functional duties of epidemiologist who received
informationon occurrence of intestinal infection nidus;
- when drawing up an epidemiological anamnesis, take into consideration
duration of incubation period (minimum and maximum).
- pay attention to factors of transmission of typhoid fever, shigellosis,
salmonellosis.
Advances in the prevention and treatment of typhoid fever.
Control of Salmonella, typhi infection transmitted from person to person
depends on high standards of personal hygiene, maintenance of a supply of
uncontaminated water, proper sewage dispose and identification, treatment, and
follow-up of chronic carriers. Hand washing is of paramount importance in
controlling person – to person spread although hands of convalescent carriers are
often contaminated after defecation detectable Salmonella are easily removed by
washing the hands with soap and water.
Typhoid fever vaccine, a saline suspension of aceton or heat/phenol killed
S.typhi enhances the resistance of human beings to infection with S.typhi under
experimental and natural conditions. Vaccine efficacy ranges from 51 to 67 %.
There is also renewed interest in testing the capsular polysaccharide of
S.typhi (Vi antigen) as a parenteral typhoid fever vaccine.
Typhoid fever vaccine should be considered for persons with intimate
continuing exposure to a documented typhoid fever carrier and for persons
traveling to areas where there is a recognized appreciable risk to exposure to
typhoid fever.
In spite of the achieved success in the pseudotuberculosis study, the
problems of the specific prophylaxis have not been worked out so far. A complex
of nonspecific measures directed at the source and transmission factors is widely
used in the medicine to prevent the pseudotuberculosis spreading.
MEASURES AGAINST SHIGELLOSIS
Prophylaxis of shigellosis includes complex of measures, directed to revelate
the source of the infection, interrupt the ways of the transmission, increase of the
organism resistance. Keeping the rules of personal hygiene and rules of food’s
cooking plays the principal role in prophylaxis of the disease. Sanitary education of
population has an important meaning in shigellosis prophylaxis too.
Prophylaxis of the toxical food infection is concluded in prevention of
infection of the food-stuff, of the reproduction of the microorganisms in the
food. It is necessary to keep the food-stuffs and prepared food at the
temperature from 2 till 4 ºC.
The mechanization and automatization of the food objects, the
elaboration of the new methods of the preserving and storage of the foodstuff, the freezing at low temperature are conductive to the successful
prophylaxis of the toxical food infection.
MEASURES AGAINST SALMONELLOSIS
The measures of prophylaxis are veterinary-surveillance upon
animals and production of meat and dairy industry, laboratory control of
food stuffs.
It is necessary to reveal carriers on milk farms, in foods, children’s and
medical establishments. The maintenance of the rules of personal hygiene and
rules of food’s cooking plays an important role in prophylaxis of
Salmonellosis.
The observance of the sanitary
and hygienic rules at processing,
transportion, keeping and preparing of the food-stuffs experts possibility of
accumulation of botulotoxin. It is necessary to perform the strict control
under sterilization and keeping preserved food-stuffs.
The explanation to the people of the rules of the procurement and
preservation of food-stuffs in home conditions has important meaning
especially such food-stuffs as meat, mushrooms, vegetables.
The measures of prophylaxis of Cholera depend on epidemic situation
in the country. The information of world health organisation about cases of
cholera in different countries has an important meaning.
The incidence of disease can be diminished by sanitary-hygienic
measures, sanitary disposal of human feces, purification and protection of
water supplies, pasteurization of milk and milk products, strict sanitary
supervision of preparation and serring of flood exclusion of persons with
diarrhea from handling food, organization of the work about diseases of
gastrointestinal tract and their examination on cholera.
Specific prophylaxis of cholera is performed by corpuscular vaccine
and cholerogen-anatoxin.
Parenterally inoculated killed complete cell vaccine has been available
for years, this vaccine stimulates high titers of serum vibriocidal
antibodies, but it does not induce antibodies to toxin. Protection by vaccine
has been induced for approximately 1 years, with vaccine efficacy
approximately 70%. Local gastrointestinal tract immunity against the
organism and against the toxin should provide a better, less reactogenic
immunogen using recombinant DNA technology an ”attenuated” V. Cholerae
organism that lacks the genes for production of the A and B subunits of
toxin was created. A plasmid containing the subunit gene was then
constructed and inserted. Thus a candidate live V.cholera vaccine
containing all the cell-was antigens necessary for adherence and the
capacity to produce only the subunit of toxin has been engineered.
5. Test questions
1. What is an epidemic nidus?
2. What does extent of the nidus depend on?
3. What are the sites a specialist must visit when carrying out epidemiological
inspections?
4. How long does it take?
5. List of documents required registering results of epidemiological inspection,
and their significance.
6. List measures necessary to be taken to eliminate epidemic nidi, and their
sequence.
7. When a nidus of a respiratory tract infection can be regarded eliminated?
8. Name the mechanism and ways of transmission of typhoid fever, shigellosis,
salmonellosis.
9. What is the epidemiological theory of correspondence? Its significance for
applied epidemiology.
6. References.
A. Basic:
Epidemiology and Fundamentals of Infectious Diseases. M.L. Volovskaya. Mir
Publisher. Moscow.
B. Adding:
A Lange Medical book. Medical Epidemiology. Second Edition. Raymond
S.Greenberg, Stephen R.Daniels. – Aplleton, Stamford, Connecticut. – 1996. –
P.195.