Gastrointestinal Infection Control Strategies

• Saran Shantikumar, Associate Clinical Professor of Public Health, and Dr. Roger Gajraj, UKHSA West Midlands wrote these notes for gastrointestinal infections.
• Warwick University created the notes in 2024.

Learning Outcomes

• The principles of public health management of gastrointestinal infections should be outlined.
• Key GI pathogens should be identified.

Key GI Pathogens

• Amoebiasis
• Bacillus
• Botulism
• Campylobacteriosis
• Cholera
• Clostridium difficile
• Clostridium perfringens
• Cryptosporidiosis
• Cyclosporiasis
• Non-STEC Escherichia coli
• Enteric Fever
• Giardiasis
• Hepatitis A
• Hepatitis E
• Histamine Poisoning (scombrotoxin)
• Listeriosis
• Marine biotoxins
• Norovirus
• Rotavirus
• Salmonellosis
• Sapovirus
• Shiga toxin producing Escherichia Coli
• Shigellosis
• Worm Infestation
• Vibriosis
• Yersiniosis

General Principles

• Identify the source of the infection.
• Identify the mode of transmission to define control measures.
• Diarrhea indicates a greater risk of contamination and spread.
• Take enteric precautions.
• Be aware of risk groups.
• Stool sampling is important.
• Exclusion is necessary.
• It is important to wait 48 hours or until microbiological clearance via negative stool samples.

Primary Prevention

• Food safety involves following the "Farm to fork" principle and milk pasteurization.
• Water quality is maintained through filtering and disinfection.
• Public awareness is important in places like open farms, summer BBQs, and during lambing season.
• When traveling abroad, get advice on food/water use and vaccines.

Food Safety and Hygiene

• At home: cook food properly, chill it correctly, clean surfaces, and avoid cross-contamination.
• When buying and eating food, check food hygiene ratings and "best before" or "use-by" dates.
• Visiting open farms carries risks.
• Lambing season can be dangerous for pregnant women.

Food Hygiene Law

• Businesses must comply with food hygiene laws.
• Hazard Analysis and Critical Control Point (HACCP) is a systematic approach.
• Review the business to identify potential risks to food safety.
• Identify critical control points to remove or reduce risks to safe levels.
• Decide on necessary actions if something goes wrong.
• Ensure procedures are followed and working.
• Keep records demonstrating procedures are being followed.

Food Hygiene Rating Scheme

• Inspections check how safely food is handled, e.g., food storage, handling, and preparation.
• Inspections ensure the premises are clean, have proper facilities and layout.
• Hygiene standards are measured through internal systems and policies.
• Frequency of inspections depends on the potential risk to public health.
• Factors determining inspection frequency: type of food, number and type of customers (e.g., vulnerable groups), processes before the food is sold or served, and hygiene standards at the previous inspection.

Enteric Precautions Advice

• Practice personal hygiene.
• Perform Environmental cleaning.
• Properly dispose of soiled materials.

Personal Hygiene: Hand Washing

• Washing hands is the most important method for preventing and controlling the spread of infection.
• Wash hands thoroughly with warm running water and soap.
• Wash before eating, handling, preparing, or serving food.
• Wash after using the toilet, changing a baby's nappy, or assisting someone with diarrhea & vomiting (D&V).
• Wash after handling or washing soiled linen, cleaning the toilet or a child's potty, and after contact with animals.
• Dry hands thoroughly using disposable paper towels or a dedicated towel.
• Supervise young children or others with learning disabilities.

Environmental Cleaning

• Clean toilet and bathroom areas regularly.
• Clean spillages immediately.
• Handle soiled linen or clothing with care.
• Use gloves and gowns.
• Properly dispose of soiled materials.

Risk Groups

• People with doubtful personal hygiene or unsatisfactory facilities are at higher risk.
• Children aged five years old or under are at higher risk.
• Food handlers are a risk group.
• Clinical, social care or nursery staff need to be careful.
• Consult specific guidelines to deal with risk groups appropriately.

GI Data Sources

• HPZone (Health Protection Team case and incident management system) is used.
• Second Generation Surveillance System (SGSS) provides local and national laboratory data.
• Gastrointestinal bacteria reference unit (GBRU) provides Reference laboratory data.
• Food, Water and Environmental Laboratory (FW&E) provides laboratory data.
• Whole genome sequencing (WGS) gathers Reference laboratory data)
• Enhanced Surveillance E.coli provides Local surveillance system data.

Stool Sample Collection

• Collect a stool sample using a clean, sterile container to avoid urine or water contamination.
• Hermetically seal the container, label it with your information, and deliver it to the lab within 24 hours.

MC&S: Culture

• For an MC&S (Microscopy, Culture, and Sensitivity) test, collect a sample using sterile techniques
• The sample is placed in an appropriate transport medium and sent promptly to the lab to ensure accurate microbial analysis.

PCR vs Culture

• Culture involves the growth of viable organisms, indicating an active infection.
• PCR involves genetic material to identify active or recovering/recovered infections
• PCR can identify the presence of certain toxins and reveal a more virulent infection.

Campylobacter

• It's the most common bacterial cause of human gastroenteritis.
• It's the most common bacterial cause of GI infection in the UK.
• It is one of the most common causes of traveller's diarrhea in the UK.
• It comes from undercooked meats, contaminated water, and animal contact.
• There is a low risk of person-to-person spread.
• Campylobacter infections are generally mild.
• It can be fatal in the very young, elderly, and immunosuppressed.
• Symptoms: diarrhea, abdominal pain, and fever.
• Less common symptoms include bloody diarrhea and vomiting.
• It typically lasts 2-3 days.
• There is no active public health management of sporadic cases due to low person-to-person transmission.
• Animal PH authorities are involved if there are clusters.

Cryptosporidiosis

• Caused by the Cryptosporidium parasite.
• Transmitted through contact with animals, person to person, and contaminated water.
• Outbreaks occur in public water supplies and swimming pools.
• Causes profuse watery diarrhea, abdominal cramps, vomiting, and fever.
• Lasts 10-14 days if healthy and causes chronic, life-threatening diarrhea in immunocompromised populations.

Enteric Fever (Typhoid, Paratyphoid)

• Salmonella typhi and paratyphi cause the same symptoms and require similar management.
• It is a serious, life-threatening disease.
• Causes high fever, abdominal pain, headache, constipation/diarrhea.
• Antibiotics are needed.
• Lasts several weeks.
• Predominantly acquired abroad via contaminated food/water.
• It is highly contagious.
• A travel vaccine is available (not perfect for typhi, ineffective for paratyphi).
• Microbiological clearance is required if you are in a risk group.
• Clearance requires three negative samples, 48 hours apart, testing a week after antibiotics.

Giardiasis

• Caused by Giardia lamblia.
• Spread through person-to-person contact, waterborne transmission, and animal contact.
• Outbreaks occur when an infected food handlers and from swimming pools.
• Causes diarrhea, greasy stools, abdominal pain, and flatulence.
• Can last 6 weeks.
• Treated with antibiotics.
• Cysts excreted in stool are resistant to chlorination.
• Avoid swimming for 2 weeks after recovery.

Hepatitis

• It's spread person-to-person, or from contaminated food/water through foreign travel.
• Sexually transmitted (e.g., MSM) and through injecting drug abuse.
• Symptom severity increases with age; 90% are asymptomatic if under 5 years old.
• Causes jaundice, fever, anorexia, weight loss, dark urine, and pale stools.
• A vaccine is available for travel and for MSM.
• The public health response involves administering vaccine and immunoglobulin (if at higher risk) and mass vaccination in school outbreaks.

Listeriosis

• Pregnant women should avoid animals that are giving birth.
• Pregnant women should not help ewes lamb or assist with calving cows or kidding nanny goats.
• Pregnant women should avoid contact with aborted or newborn lambs, calves, or kids and should not touch the afterbirth, birthing fluids, or contaminated materials.
• Pregnant women should avoid handling clothing, boots, or materials contaminated by animals that gave birth, their young, or afterbirths.

Norovirus

• It's a virus.
• It's highly infectious, spreading through person-to-person contact, inhalation, ingestion, and environment-to-person transmission.
• Causes a sudden onset of nausea, projectile vomiting, and watery diarrhea.
• Has a brief incubation period.
• Outbreak management requires guidelines around PPE and cleaning.
• It contributes to winter pressures.

Salmonella

• It comes from undercooked meats, raw eggs, contaminated milk, dairy products, and salads.)
• It spreads through person-to-person contact.
• Can be identified by watery diarrhea, abdominal pain, headache, vomiting, and fever.
• Last for 4-7 days.
• There are >2500 serotypes of Salmonella.
• Can be used to trace where infections have come from (WGS).

Shigella (bacterial dysentery)

• Causes diarrhea (watery, slimy, or bloody), fever, and abdominal cramps.
• Includes Shigella sonnei, boydii, dysenteriae, and flexneri.
• Shigella sonnei presents as a mild illness.
• Illness lasts one day to 1-2 weeks.
• Spreads through person-to-person contact, environmental sources, sexual contact (MSM), and contaminated food/water from foreign travel.

Shiga toxin producing Escherichia coli (STEC)

• Can cause mild gastroenteritis, severe bloody diarrhea, haemolytic uraemic syndrome (HUS), and death.
• HUS results in kidney failure and thrombotic thrombocytopaenic purpura.
• Main reservoir: cattle, other ruminants (goat, sheep, deer, giraffes).
• Has a low infectious dose.
• Can be consumed from contaminated food or water and through direct or indirect contact with animals or their feces.
• Can spread person-to-person (usually among young children).

Escherichia coli Classification

• Good E. coli is a Gut flora and can cause UTI
• Naughty E. coli doesn't produce Shiga toxin and causes a usually mild and self-limiting symptom of Diarrhoea
• Evil E. coli: STEC
• Includes serotype 0157
• Includes serotypes 026, 0123, 0113, 088, 055, 09, 037, 038, 078, 0114, 0146, 0156, 0174, 0183
• Can cause Diarrhoea OR severe GI infection OR HUS/death

This quiz assesses effective strategies for controlling gastrointestinal infections, including identifying causative agents and minimizing transmission risks. Questions cover public health measures, risk factors, and pathogen clearance in vulnerable populations. It also covers important strategies for implementing HACCP in food processing industries.