Gastro- intestinal diseases المرحلة الرابعة اعداد د. وفاء محمود جاسم

Main Subjects 1- Main lines of infectious agent , diagnosis and prevention 2- Gastrointestinal infections 3-Food born infection 4- Outbreaks 5- Epidemiological investigation

Infectious Agents: There are many enteric pathogens implicated in outbreaks of gastrointestinal disease, including 1- Bacteria such as E. coli, Salmonella and Shigella 2- Parasites such as Cryptosporidium, Cyclospora, and Giardia; 3-VIruses such as noroovirus.

Usual incubation (range) Organism Usual incubation (range) Campylobacter 2-5 days (1-10 days) Giardia 7-10 days (3-25 days) Salmonella 12-36 hours (6-72 hours) Cryptosporidium 7 days (1-12 days) Shigella 1-3 days (12-96 hours) Cyclospora 7 days (1-2 weeks) E. coli 3-4 days (1-10 days) Norovirus 1-2 days (10-72 hours)

Diagnosis and treatment Diagnosis: Stool specimens can be tested for the presence of any of the enteric pathogens. In outbreak situations arrangements can be made on a case-by-case basis to test stool specimens Treatment: Treatment of gastrointestinal illness, including the use of antibiotics.

PREVENTION AND CONTROL 1-Cohorting of symptomatic patients is essential. Individual staff should be restricted to caring for only one cohort of patients. 2-Staff floating should be minimized. 3- If norovirus is suspected or confirmed as the cause of an outbreak, symptomatic staff should be excluded from all food handling duties for 72 hours past symptom resolution or 72 hours past the date a specimen positive for norovirus was provided, 4- If a bacterial or parasitic agent is suspected or confirmed, symptomatic staff should be tested and allowed to return to food handling duties when diarrhea is resolved

PREVENTION AND CONTROL 5-Patients with gastrointestinal symptoms should be placed on standard plus contact precautions for the duration of their illness. Patients who test positive for a bacterial or parasitic agent should remain on precautions until a negative stool specimen is produced. 6- For patients treated with antibiotics the stool specimens should not be collected until 48 hours after cessation of antibiotic therapy.

PREVENTION AND CONTROL 7- Proper hand hygiene should be emphasized to all staff and residents Noroviruses are highly infectious,. They are easily spread from one person to another and are found in large quantities in the stool or vomitus of an infected person. Staff should wash their hands with soap and water after patient care. Hands should be dried with a dry, disposable paper towel.

PREVENTION AND CONTROL 8-Articles contaminated with infective material, such as soiled linens and clothing, should be discarded or bagged and labeled before being sent for washing. 9-Special attention should be paid to environmental cleaning and disinfection.

Gastrointestinal infections The term of the Gastrointestinal infections extends to the following areas: 1- zoonotic disease 2- general gastro-intestinal illness 3- water related issues both microbiological and chemical 4- food related issues related to human infective diseases

Foodborne illness Foodborne illness (also foodborne disease and also referred to asfood poisoning)  is any illness resulting from thecontaminatedfood, pathogenic  bacteria, viruses, or parasites that contaminate food  as well as chemical or natural toxins such as poisonous mushrooms.

Foodborne illness Terms applied to illness acquired by consumption of contaminated food (food born intoxication, food born infection ) 1- Illness caused by toxicants elaborated by bacterial growth before consumption (Staphylococcus aureus ) 2- Toxines elaborated in intestine (Clostridium ) 3- Illness caused by bacterial infection with short incubation period (Salmonelosis

Symptoms of food born illness 1- Common symptoms of food born illness are diarrhea and/or vomiting, typically lasting 1 to 7 days. Other symptoms might include abdominal cramps, nausea, fever, joint/back aches, and fatigue. 2- What some people call the “stomach flu” may actually be a food born illness caused by a pathogen (i.e., virus, bacteria, or parasite) in contaminated food or drink.  3-The incubation period (the time between exposure to the pathogen and onset of symptoms) can range from several hours to 1 week.

Causes of food born disease 1-Cryptosporidiosis (Cryptosporidium) 2- Escherichia coli 3- Giardiasis (Giardia) 4-Listeriosis (Listeria monocytogenes) 5-Norovirus Infection 6-Salmonellosis (Salmonella)   7-Shigellosis (Shigella) 8-Toxoplasmosis (Toxoplasma gondii) 9-Vibrio Infection (Vibrio parahaemolyticus) 10 Yersiniosis (Yersinia species)

foods Associated with Food born Illness Raw foods of animal origin, that is, raw meat and poultry, raw eggs, unpasteurized milk Fruits and vegetables can also be contaminated with animal waste Unpasteurized fruit juices can also be. contaminated if there are pathogens on the fruit that is used to make it Any food item that is touched by a person who is ill with vomiting or diarrhea, or who has recently had such an illness, can become contaminated. When these food items are not subsequently cooked (e.g., salads, cut fruit)

Prevention of good born infection (1)  identify and remove contaminated products from sale (2)  identify and correct faulty food-handling and food-production practices (3) understand how food born diseases are caused and spread (4) detect new food born disease-causing agents (5) develop food safety programs and policies. 

Out breaks The occurrence in a community or region of cases of an illness with a frequency clearly in excess of normal expectancy

Types of out break 1- Common source – All victims acquire the infection from the same source (e.g. a contaminated water supply 2-Continuous source – Common source outbreak where the exposure occurs over multiple incubation periods 3- Point source – Common source outbreak where the exposure occurs in less than one incubation period 4-Propagated – Transmission occurs from person to person

Epidemiological Investigation 1-. Establish the existence of an outbreak 2. Confirm the diagnosis 3. Establish the case definition and count cases 4. Relate the outbreak to time, place and person 5. Determine who is at risk of becoming ill

6. Formulate a tentative hypothesis 7. Compare the hypothesis with the established facts 8. Plan a detailed epidemiologic investigation 9. Prepare a written report 10. Implement control and prevention measures