Community health

Health services

Major services in hospital1) Accident and emergency service - for the initial       assessment and treatment of people who develop       a sudden illness or who sustain an accident

2) In-patient service - service for patients who have        to be hospitalised 3) Specialist out-patient service - for treatment of        mild cases, and for particular types of diseases,        such as those of eyes, teeth, ears and noses,        chests and lungs, of old people and mental        illnesses.

Health services for children 1) Family health services

    The Family Health Services operates Maternal and Child Health Centres, providing a comprehensive health programme for children up to five years old. Under this scheme, the followings are provided

a) Immunisation programmes for infants and children.b) Assessment of children at different ages to detect         early developmental abnormalities, and referring any         child to specialist care when necessary.c) Health talks and counselling on child care offered to         parents and expectant mothers.d) Telephone service available to answer enquiries from the         public.

2) Child Assessment Services    There are two Child Assessment Centres for children from birth to 12 years old. They provide comprehensive physical, psychological and social assessment as well as therapy, parental counselling and referral for appropriate placement of the child in the various institutions and centres run by the government and voluntary agencies.

3) Dental Services    The School Dental Care Service provides regular dental examinations, simple dental treatment and oral health education to primary school children.

4) School Medical Services

    The School Medical Service Scheme offers an economic form of medical treatment service to all school children in Primary 1 to Secondary 3 with the main objective of allowing school children to have early detection, diagnosis of defects and continued medical supervision.

Health services for the Physically and Mentally Handicapped1) Prevention and early identification

    Prevention of diseases, disabilities and accidents has an important effect on reducing the rehabilitation services required. The main aim is to prevent disability bya) improving health education within the community,b) establishing neonatal screening programmes for common        treatable congenital disorders,c) introducing immunisation programmes for controlling        common communicable diseases,d) controlling usage of medicines hazardous to health,e) improving environmental living conditions by prohibiting        usage of chemicals,f) holding annual campaigns on road, industrial, home and        recreational safety.

    The comprehensive observation scheme by the Family Health Centres for all infants between birth and the age of five identifies children with risk of developing disabilities and referred them for special attention. Observation of children above the age of five is conducted in primary schools by the Education Department. A combined screening programme provides all Primary 1 population with audiometric, vision and speech screening and identification of children with learning difficulties.

2) Medical services    Medical services for the handicapped are available in most hospitals, day centres, out-patient clinics and infirmaries. As for mental health services, the Castle Peak Hospital and Kwai Chung Hospital provides facilities for sophisticated treatment.

    Psychiatric units are also available at the regional and district hospitals. In parallel to these, psychiatric centres provide a wide range of out-patient treatment, assessment, counselling and after-care services on a regional basis.

3) Rehabilitation services    To enable the disabled to recover to the fullest extent which their disabilities permit, special treatments are provided, e.g.

a) Physiotherapy.b) Occupational therapy.c) Prosthetic-orthotic Services (this allows patients with physical        disability to be fitted and supplied with various prosthetic and        orthotic appliances designed to restore wholly or partly their       bodily functions and /or appearance). Other social,         rehabilitative services provide counselling, housing, training,       day and residential care, transport, access, sport         and recreation, and welfare grants for the disabled.

Health services for the old

Most hospitals include a Geriatrics Department providing special treatment for the aged. There are also special geriatrics department in some out-patient clinics and day hospitals. Besides, Community Nursing Services provide continuing care to patients discharged from hospitals and provides domiciliary medical care and support for the elderly in their own homes.

Food & water hygiene

Effect of various factors on bacterial growth

1) Temperature - With a rise in temperature, there is a       steady increase in the growth rate of bacteria,       reaching a maximum at the optimum temperature.       Further increase in temperature, however, leads to a       rapid drop in the growth rate due to the denaturation       of enzymes. Low temperature also slows down the       rate of bacterial growth.

2) Nutrient - Bacteria need food for growth. Food       provides the energy for cellular activities and the       material for forming cellular structures. Food       availability is usually one of the most important       factors affecting the growth of bacteria.

3) pH - Bacterial growth is also affected by the pH       of the surrounding medium. Bacteria grow best       at a particular pH, the optimum pH. The rate of       growth drops rapidly as the pH deviates from the       optimum value.

4) concentrated solution - When the bacteria are       surrounded by hypertonic solutions, water will be       drawn out of the cells by osmosis. As a result, the       growth of bacteria may be slowed down. If too       much water is lost, the bacteria may die and       growth stops completely.

Principles of proper food handling

If food is handled by an infective person, the contaminated food may cause infections. Persons who handle food should always wash their hands first, especially after visiting the toilet. In order to prevent food from being contaminated by vectors of diseases, such as flies and cockroaches, food should be covered or wrapped, and stored under suitable conditons.

If fresh foods such as meat, fish, fruits and vegetables are not preserved immediately after they are harvested, they may become spoiled very quickly. Food spoilage is due to the action of micro-organisms which feed and multiply on food. Spoiled food usually has an unpleasant smell and taste that makes it unsuitable to eat. Furthermore, the pathogens it contains are hazardous to health.

Food PreservationFood Preservation

Heating

– kill most microorganisms & their spores by high temperature

Canning & Bottling

– sealing in cans to avoid bacterial   entry

– should work together with    sterilization

Food PreservationFood Preservation(storing food under conditions that inhibit the

growth of microorganisms or killing them)

Refrigeration (4°C)

– to decrease or stop the activities & growth of microorganisms (NOT killing them)

Food PreservationFood Preservation

♣Freezing (-20¢XC for deep freezer)

– stop the activities of micro-organisms

– NOT killing them

– they can resume activity when ice melts

Pasteurization

– kill most microorganisms without changing the flavour of milk

– 72°C for 15s and then quickly cooled (or 63°C for 30 minutes) & bottled

UHT (Ultra High Temperature) treatment

– common in killing bacteria in milk

– superheated to ~150°C for a few

        seconds and then sealed

Food PreservationFood Preservation

To show the effect of pasteurization on To show the effect of pasteurization on milkmilk

1) Expose some fresh milk to air for one hour. Then pour 20 cm3 of the milk into each of three conical flasks

2) Flask 1 - Boil a flask of milk.Flask 2 - Put milk in a water bath at 63°C for 30 minutes. Flask 3 - Leave the flask of milk at room temperature.

3) Plug all three flasks with sterile cotton wool.

4) Transfer 1 cm3 of milk from each flask to an agar plate with nutrient agar. Swirl the plate to spread the milk over the agar surface.

5) Seal the agar plates with adhesive tape

6) Incubate the plates at 25°C for at least 48 hours.

7) Count the number of bacterial colonies in each plate.

Results:

Plate 1 - least bacterial coloniesPlate 2 - slightly more bacterial coloniesPlate 3 - most bacterial colonies

Explanation

Plate 1 - sterilization kills nearly all the bacteriaPlate 2 - pasteurization kills quite a number of    bacteria, but not as effective as sterilizationPlate 3 - it shows the number of bacteria present in the   untreated milk.

Drying (Dehydration)– micro-organism in the food become inactive and

cannot multiply if water is removed from food. Thus the food can be stored for a long time without spoilage. This method can be used to preserve meat, fish, fruits and vegetables.

Food PreservationFood Preservation

Food can be dried in air, under the sun or by vacuum (in which water evaporates from food under low pressure and at temperature well below boiling point of water, e.g. in  making milk powder that does not change its flavour or destroy vitamins)

Food PreservationFood PreservationOsmotic preservation

by adding salt (e.g. for fish and meat such as ham) or concentrated sugar solution (e.g. for jam preparations)to remove water from micro-organisms by osmosis  to kill them

Preservatives – add some chemical to food to stop bacterial

growth or kill them, e.g. sodium nitrite

Food PreservationFood Preservation

Antioxidants - chemicals which stop oxidation and thus prevent organisms from respiring. For instance, sulphur dioxide is often used to preserve fruit juices and soft drinks. It forms a reducing agent which kills micro-organisms by removing oxygen.

Irradiation     The food processing industry is using ionizing radiation as an alternative to chemical preservatives for certain foods. Radiation kills microorganisms, parasitic worms and insect pests, inhibits the growth of sprouts on potatoes and onions, extends refrigerated shelf life, and delays ripening in some fruits. For many foods, treatment with radiation does not affect the flavour, texture, or colour of the food. The nutrient quality of irradiated foods is equal to foods processed by other commercial processing methods.     Irradiation never makes foods radioactive. It does, however, create small chemical changes on certain food molecules, producing unique radiolytic products. The long-term safety of the consumption of such compounds is under investigation.

Irradiation     Many consumers react negatively to the use of radiation on foods, associating radiation with cancer. Some may confuse it with food contamination by radioactive particles, such as that occurs in the aftermath of a nuclear accident. For this reason, some suggest using the term pico wave, believing consumers will accept that term as readily as they did microwaves.      Irradiation reduces food wastage and can replace some costly pesticides. Unfortunately, poor countries that have many hungry people and little food for them lack irradiation technology, and much of their food rots or is eaten by insects.

Water purificationWater purification

Why needed?Why needed?

Water for domestic use is mainly supplied Water for domestic use is mainly supplied from rivers, lakes or reservoirs which collect from rivers, lakes or reservoirs which collect rain water from large areas called catchment rain water from large areas called catchment areas. Waters from these sources contains areas. Waters from these sources contains particles of different sizes, microbes and particles of different sizes, microbes and chemical substances. The water has to be chemical substances. The water has to be purified and treated before it is supplied to purified and treated before it is supplied to homes for domestic use. homes for domestic use.

StepsSteps1) Screening - using metal grids at the place where 1) Screening - using metal grids at the place where           water is  taken from the reservoir to keep out           water is  taken from the reservoir to keep out weeds           and large  particlesweeds           and large  particles

2) Sedimentation - Water is pumped to the 2) Sedimentation - Water is pumped to the sedimentation           tank where large particles will sedimentation           tank where large particles will settle to the bottomsettle to the bottom

3) Filtration - water is passed through filter beds of 3) Filtration - water is passed through filter beds of sand           and gravel to remove suspended particlessand           and gravel to remove suspended particles

4) Chlorination - chlorine is added to kill harmful 4) Chlorination - chlorine is added to kill harmful bacteria. bacteria.

5) Fluoridization - fluorine is added to water 5) Fluoridization - fluorine is added to water to  strengthen          the  enamel of teeth to prevent to  strengthen          the  enamel of teeth to prevent tooth decaytooth decay

6) Storage - water is pumped up to water towers for 6) Storage - water is pumped up to water towers for           storage from where water is delivered to our           storage from where water is delivered to our homes homes

pump

metal grids (screening)

sedimentation tank

water tower

pump

chlorine addedfilter bed

sand

gravelconsumer

water from

reservoir

Disease patternsDisease patterns

Endemic (Endemic (地方病地方病 ))

An endemic disease is one that occurs regularly in a certain region but clinically recognizable in only a few.            

Epidemic (Epidemic (疫症疫症 ))

Epidemic diseases are infectious diseases which occur in outbreaks when a large number of people are affected at the same time, but later the disease is brought under control.

Recent trend in modern societiesRecent trend in modern societies Shift from infectious diseases to chronic diseases Shift from infectious diseases to chronic diseases (which are more persistent, e.g. diabetes, tuberculosis and (which are more persistent, e.g. diabetes, tuberculosis and allergies, degenerative conditions (such as heart and allergies, degenerative conditions (such as heart and circulatory diseases, strokes, arthritis), kidney failure, circulatory diseases, strokes, arthritis), kidney failure, haemophilia and cancers) + mental ill health.haemophilia and cancers) + mental ill health.

Cause: Many infectious diseases (e.g. bubonic plaque, malaria, small pox and measles) now under control due to

Understanding of the nature of infectionUse of antibiotics and other drugsImprovement in nutrition and personal health/ sanitation

Device of more effective preventive measures such as vaccines

Higher awareness of personal and community hygiene due to health education

On the other hand, people live longer and a great proportion reach old age. It is in the elderly that many chronic diseases show up.

Under long periods of continuous or intermittent discomfort, sufferers of chronic diseases may become much weakened and disabled. Medical and nursing care has to be maintained for a long time.

Relation of major health problems of a modern Relation of major health problems of a modern industrialized society to its physical and social industrialized society to its physical and social

environmentenvironment1) High concentrations of air pollutants in industrialised city cause more acute cardiac and respiratory disorders2) More common contact with chemical agents, some of which are disease-causing. For instance, a person‘s occupation may expose him or her to special chemicals hazardous to health.3) Living habits like overeating, particularly of fatty foods, and habits like cigarette smoking and drinking alcohol, all contribute to many chronic diseases associated with the heart and respiratory tract. 4) Manual work has been largely replaced by machines. This together with public and private transport has given many people a life-style in which exercises has very little part. Lack of exercises has now been recognised as a health risk and possibly lead to certain chronic diseases.

Some vaccination Some vaccination programsprograms When antigens of pathogenic microorganisms are artificially When antigens of pathogenic microorganisms are artificially

introduced into the human body, the immune system is introduced into the human body, the immune system is stimulated so that the body becomes immune to subsequent stimulated so that the body becomes immune to subsequent infections by the living pathogens. Such technique is called infections by the living pathogens. Such technique is called immunization or vaccination. One vaccination schedule for immunization or vaccination. One vaccination schedule for children in Hong Kong is as shown below:children in Hong Kong is as shown below:

Age Immunisation recommended

NewbornB.C.G. 卡介苗Polio 小兒痳痺 Type IHepatitis & B Vaccine - First dose

1 month Hepatitis Vaccine - Second dose

2-4 monthsTriple vaccine (diphtheria, tetanus & whooping   cough) - first dosePolio trivalent - first dose

Age Immunisation recommended

3-5 months

Triple vaccine (diphtheria, tetanus & whooping cough) - second doseHepatitis B vaccine - third dose

4-6 months

Triple vaccine (diphtheria, tetanus & whooping cough) - third dosePolio trivalent - second dose

1 year MMR vaccine (measles, mumps & rubella)

1O year Triple vaccine (diphtheria, tetanus & whooping cough) - booster dosePolio trivalent - booster dose

Age Immunisation Recommended

Primary 1Combined vaccine (diphtheria & tetanus) - booster dosePolio trivalent - booster dose

Primary school children

B.C. G. (after tuberculosis testing)

Primary 6 Combined vaccine (Diphtheria & tetanus) - booster dosePolio trivalent - booster dose

Primary 6 (girls)

Rubella vaccine

These vaccinations effectively wiped out or controlled a These vaccinations effectively wiped out or controlled a large no. of diseases in children (e.g. small pox, measles, polio large no. of diseases in children (e.g. small pox, measles, polio & tuberculosis)& tuberculosis)

Role of immunization in controlling infectious diseases Immunization, applied artificially, induces resistance to specif

ic infection. It is valuable not only in the protection of the individual but also to prevent the spread of certain infections, mainly those that spread directly from one person to another, e.g. poliomyelitis, measles or smallpox. When a significant proportion (usually more than 60%) of the population is immunized, protection of unimmunized is also achieved through a decrease in exposure to the infectious agent. This is because successful transmission from an infected person to a susceptible person is much more difficult. The small numbers of vulnerable individuals are, as it were, protected by being scattered among people who are incapable of catching the infection and passing it on. This is how immunization controls infection.

Sexually Transmitted Diseases (STD) STDs refer to infections which can be spread from one person to another through sexual contact. They can also be transmitted from an infected mother to her child when it is still in the uterus or when it passes out through the vagina at birth. Examples of common serious STDs are:1) Syphilis 梅毒 - caused by bacteria

skin rashes caused by syphilis

2) gonorrhoea 淋病 - caused by bacteria and3) AIDS (Acquired Immune Deficiency Syndrome) 愛滋病 - caused by the HIV virus

Means of transmission

Since HIV cannot survive outside the human body, AIDS can be contracted only through

a) blood (e.g. sharing of contaminated syringes for injecting drugs) and

b) other body fluids (e.g. semen, vaginal secretion), e.g. due to casual sex (both homosexual and heterosexual)

c) Breast milk. Saliva, tear, urine, sweat and sputum may contain a very sm

all amount of HIV, but this amount is not known to cause infection.

Preventive measures against the spread of STDs1) Avoid sex outside marriage, although the use of con

doms may reduce the chance of infection2) Avoid contact with contaminated blood, e.g. wounds

should be covered up, contaminated syringe should not be used and contaminated materials should be handled properly.

3) Early check-up and treatment of diseases in a social hygiene clinic

4) Sex education for adults and school children to help them understand the risks of casual sex, the early symptoms of diseases, and where they can obtain information, advice and treatment.