Prevention of Communicable Diseases

byDr. TK Au of UHS

MBChB, MRCP(UK), DPD(Cardiff), DCH(Syd)

Communicable diseases

Definition: diseases that can be transmitted and make people ill

Statutory notifiable diseases According to the law, a doctor has to notify

the Department of Health when he/she has the reasons to suspect his patient is suffering from the disease

Eg. Chickenpox, tuberculosis, avian flu, SARS

Communicable diseases

Diseases that can cause outbreak in institutions Influenza-like illness Acute gastroenteritis Hand, foot and mouth disease (HFMD) Acute conjunctivitis

Chain of Propagation of Communicable diseases

Contact transmission

Through direct body contact with the infected persons

Indirect through contact with objects contaminated by infective agents, eg sharing towels, combs and clothes

Example Hand, foot, mouth disease Acute conjunctivitis Head lice Scabies Chickenpox

Droplet transmission

Inhale or contact of droplets expelled from the sick during sneezing, coughing, spitting and speaking

Subsequent touching of mucous membranes of the mouth, nose and the eyes with hands contaminated with infective agents

Eg. Influenza, common cold, pneumonia

Air-borne transmission

The infective agents float in the air for some time

Enter the body through the respiratory tract

E.g. Chickenpox, measles, pulmonary tuberculosis

Food/water-borne transmission Through ingestion of contaminated food

or water, or use of contaminated utensils E.g. Viral gastroenteritis, cholera,

hepatitis A

Break the Chain

XX

Disinfection

Build up Personal Immunity by Immunization and Healthy Lifestyle

Good Personal and

Environment & Food Hygiene

Early Detection, Isolation, and Treatment of patients

Personal Hygiene

The most important part of infection control as many diseases are transmitted through contact or droplet

1. Hand hygiene2. Cough etiquette

Hand Hygiene – When?

1. Before touching the eyes, nose and mouth2. Before eating or handling food3. After using the toilet4. When hands are contaminated by respiratory

secretions, e.g. after coughing or sneezing5. After touching public installations or

equipment e.g. escalator handrails, elevator control panels

or door knobs6. Before and after visiting hospitals7. After making contact with animals or poultry8. After handling garbage

Hand Hygiene – How?

Handwashing with soup and water When hands are visibly soiled When hands are likely contaminated with

body fluid e.g. after using the toilet, after coughing or

sneezing Use of 70-80% alcohol-based hand rub

Use of 70-80% alcohol-based handrub

Apply a palmful of handrub

Use at least 20s to rub all surfaces of hands and fingers

Until the hands are dry

Personal Hygiene

The most important part of infection control as many diseases are transmitted through contact or droplet

1. Hand hygiene

2. Cough etiquette3. Other

Cough Etiquette

Cover both the nose and mouth with tissue paper when coughing or sneezing

Do not spit Wrap up sputum with tissue paper and

discard it into garbage bin with lid or flush it away in the toilet

Wash hand immediately Put on a surgical mask if you have

respiratory infection symptom

Environment hygiene

Regular cleansing and disinfection Maintain good indoor ventilation – open

windows widely Keep worktops n the kitchen clean Cover garbage bins Wrap up rubbish properly before

discarding it into garbage bins Empty garbage bins at least once a day Do not keep pets like dogs, cats, or birds

in hall

To stop perpetuation of communicable diseases

XX

Disinfection

Build up Personal Immunity by Immunization and Healthy Lifestyle

Good Personal, Environment & Food Hygiene

Early Detection, Isolation, and Treatment of patients

Build up Immunity

Vaccination Tuberculosis (BCG vaccine) Hepatitis A & B Diphtheria, Pertusis, Tetanus Measles, Mumps, Rubella Chickenpox Pneumococcal HPV Others – before travel

Healthy lifestyle

Build up Immunity

Healthy lifestyle Enough rest/sleep Regular exercise Balanced diet Maintain a normal body weight, i.e. BMI

18.5-23 Do not smoke

To stop perpetuation of communicable diseases

XX

Disinfection

Build up Personal Immunity by Immunization and Healthy Lifestyle

Good Personal, Environmental, Food Hygiene

Early Detection, Isolation, and Treatment of patients

Bleach

Active ingredient: sodium hypochlorite (次氯酸鈉 )

Action: denatures protein in virus, bacteria and fungus

Pros: Works quickly, widely available, low cost

Cons: Irritates mucous membranes, skin and airway Decomposed under heat or light Reacts readily with other chemicals

Use of Bleach – Tools and Equipment Cleansing tools: brush, mop, towel, spray

can and bucket Cleansers/disinfectants: bleach and

water Measuring tools: tablespoon and

measuring cup Protective gear: mask, rubber gloves,

plastic apron and googles (recommended)

Use of Bleach - Procedures

Keep windows open, ensure good ventilation Wear protective gear Use COLD WATER for dilution

hot water decomposes the active ingredient of bleach

Bleach with 5.25% sodium hypochlorite 1 in 99: mixing 10ml of bleach with 990ml of

water, for general household cleaning 1 in 49: 10ml of bleach with 490ml of water,

disinfect surfaces or articles contaminated with vomitus, excreta and secretion

Use of Bleach - Procedures

Rinse disinfected articles with water and wipe dry

Cleansing tools soak in diluted bleach for 30mins rinse thoroughly before reuse

Wash hands with liquid soap, dry hands with a clean towel or disposable towel

Use of Bleach - Precautions

If bleach gets into the eyes, immediately rinse with water for at least 15 minutes and consult a doctor

Bleach should not be used together or mixed with other household detergents Reduce effectiveness If mixed with acidic detergents -> toxic gas

Bleached should be stored in a cool and shaded place Undiluted bleach liberates a toxic gas when

exposed to sunlight

Disinfection

Regular cleansing and disinfection of Rooms, kitchen, toilets, bathrooms Door knobs and lift buttons Frequently touched surfaces – furniture,

computer keyboards For obvious contaminants e.g.

respiratory secretions, vomitus or excreta Wipe away with disposable towels Disinfect the surface and neighboring areas

with appropriate disinfection Non-metalic surface – 1:49 bleach Metalic surfaces – 70% alcholol

To stop perpetuation of communicable diseases

XX

Disinfection

Build up Personal Immunity by Immunization and Healthy Lifestyle

Good Personal, Environmental, Food Hygiene

Early Detection, Isolation, and Treatment of patients

Early Treatment

Seek and follow medical advice immediately if you feel unwell

Early Isolation

Stay at home and do not attend school if your doctor tell you to do so. This is usually when one is Febrile (Ear temperature ≥ 38˚C) Suffering from chickenpox, hand-foot-mouth

diseases, measles, certain form of tuberculosis Minimize contact with other people as far as

possible. Avoid group activities. Maintain good personal hygiene People with respiratory infection symptoms

and their close contacts should wear surgical mask

Early Detection

Inform the Hall Management if you suspect that there is clustering of diseases, e.g. Gastroenteritis Influenza-like illness Hand-foot-mouth disease Acute conjunctivitis

Summary

Chain of Propagation of Communicable Diseases

Break the Chain Good personal, environment and food hygiene

Hand washing and alcohol handrub Build up immunity by vaccination and healthy

lifestyle Disinfection Early detection, isolation and treatment of

patients

References

Infection Control Corner, Centre for Health Protection http://www.chp.gov.hk/en/guideline_infectio

n/346.html Hand washing video, from the

University of Leicester http://www.youtube.com/watch?v=sjpWwjz

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