Past Year Eh

8/3/2019 Past Year Eh

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SHORT NOTE (10 MARKS)

1. 1. Health hazards from improper waste disposal (EH4)The accumulation of solid wastes in man's environment constitutes a health hazard because of

the following reasons:

1. There are many harmful agents in the wastes. The most important biological agentswhich pollute water and food and cause intestinal infections are cholera, typhoid,

dysentery, infectious hepatitis (Hepatitis A), polio and some parasitic infestations.2. The organic portion of solid waste ferments and favours the breeding offlies and other

insects which transmit infections.

3. Refuse is the main source of food forrats and in rubbish dumps they quickly proliferate.Diseases for which rats may be a reservoir include plague, murine typhus, leptospirosis,rat bite fever and salmonelosis.

4. Thepathogens may be conveyed to man through flies (which transmit infectionsmechanically) and dust (may harbor tubercle bacilli).5. Carelessly dumped refuse canpollute both surface and ground water, and soil.

6. There is risk ofatmospheric pollution if there is accidental or spontaneous combustion ofrefuse.

7. Constitute a nuisance ofsight and smellfrom an aesthetic point of view.8. Heavily dumped refuse can causeroad block, flooding and even accidents.9. Some of the refuse and waste from construction sites can become non-essential water

receptacles and favour thebreeding of vectors like1. Aedes mosquito which transmits Dengue and Dengue Haemorrhagic fever,

Yellow fever, and other arboviral infections,

2. Culex mosquito which transmit Filariasis, Japanese Encephalitis etc.3.

Can cause smoulderingfire.

1. 2. Drop latrine and health hazards (EH3)a) A latrine built over the sea, river, or other body of water into which excreta drop directly is

known as an overhung latrine.

b) If there is a strong current in the water, the excreta are carried away.

c) It may be the only feasible type for communities living over water, but it will give serioushealth risks of faecal water-borne diseases.

1. 3. Jitra bowl pour flush latrine (EH3)


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a) It is a simplified version oflow-cost, pour-flush, water-seal, pit latrine which is now

recommended for use in rural areas of Malaysia.

b) The water-seal prevents the escape of gases from the digestion of organic wastes in the pit

into the latrine superstructure.

c) It is similar to the conventional water-closet bowl except thepit is situated behind the

latrine and provided with a short length of pipe or channel from the pan to the pit, and a small

vent pipe is provided to allow the escape of gases into the atmosphere.

d) It is easy to dislodge if the pit has concrete lining with proper cover so that it can be used

for a longer period of time.

e) It is being introduced via the health services and by means of sanitation campaigns

throughout the country.

1. 4. Water seal or pour flush latrine (EH3)a) This is a variation of the pit latrine.

b) Instead of the 'keyhole' orifice in the concrete slab over the pit, a receptacle or bowl with a

shallow water-seal is provided to receive the excreta.

c) After defaecation, the person using the latrine flushed away the excreta in the water-seal

bowl with a small bucket of water.

d) As water is poured to flush the water-seal bowl, this type of latrine is sometimes called the

pour-flush latrine.

e) A water-seal prevents flies, mosquitoes and odor reaching the latrine from the pit.

f) It has accordingly gained wide acceptance by rural communities in many countries in

South-East Asia -e.g. Siamese bowl pour-flush latrine.

g) The disadvantages are, it need reliable water supply, and cannot be dislodge when the pit

is full.

1. 5. Stabilization pond (Oxidation Pond) (EH3)a) A more recent method employed for small communities is the Stabilization Pond (also

known as Oxidation Pond or Sewage lagoons).


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b) In this system, raw or partially treated sewage is dischargedinto a pond and is "purified"

by natural processes under sunlight.

c) The organic matter is broken down by micro-organisms into carbon dioxide and other

substances, some of which act as nutrients of green algae whose chlorophyll apparatus activated

by sunlight liberates oxygen.

d) This oxygen converts the unstable material in sewage into stable harmless compounds and

deodorises the process at the same time.

e) This system is used for most of the new housing projects in Peninsular Malaysia.

f) New housing schemes with 100 or more units be required central stabilization pond.

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6. Dumping methods in final waste disposal (EH2)

Can be either open dumping or dumping at sea.

a) Open dumping:Refuse is dumped into low-lying areas. Hauling is the only cost, andtherefore a cheap method of refuse disposal. It is widely practiced, but is a very insanitary

method.

The drawbacks of open dumping are:

i. the refuse is exposedto flies and rodents

ii. it is a source of nuisance from the smell andunsightly appearance

iii. air pollution caused by loose refuse dispersed by thewind

iv. pollution of surface and ground water

b) Dumping at sea:

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Practiced in coastal areas and islands, and may be used as a method of land reclamation.2. Disadvantage - the rubbish may float back to the beaches and shores and may also causetoxicity to fish and flora.

3. WHO Expert Committee (1967) condemned dumping as "a most insanitary method thatcreates public health hazards, a nuisance, and severe pollution of the environment."

1. 7. Sanitary land fill (EH2)


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a) Ideally, a sanitary landfill site should be on inexpensive land within economical hauling

distance, have year-round access, and be at least 1,500 m downwind from residential andcommercial neighbors.

b) Preparation of the site involves fencing (pagar), grading, stockpiling of cover material,

construction of beams, landscaping, and the installation of leachate collection and monitoringsystems.

c) Wells for gas collection may also be provided. Landfill liners are natural or synthetic

materials used to line landfills so that leachate cannot leach into the groundwater.

d) Advantages - similar to controlled tipping, butmore sanitary and proper gas and leachate

collection to prevent pollution to ground water sources.

e) Disadvantages -more expansive, technical expertise is necessary and leachate need to be

collected and properly treated at the same site.

1. 8. Incineration (EH 2)a) A method of choice where suitable land is not available. It is a process by which solid,

liquid and gaseous combustible wastes are converted through controlled combustion to a residue

which contains virtually no combustible matter and to gases which are released into theatmosphere after passing through the filters.

b) Advantages - No nuisance if properly planned, no air pollution if temperature is high (at

least 1000 degrees C). It is a very efficient method and it can run 24 hours a day in large citieswhere not enough land for landfills.

c) Disadvantages - it is an expensive method with high technicality, and materials like bottles

and cans remain.

1. 9. Sources of water pollution (EH7)a) Definition: The presence of impurities in water in such nature as to impair the use of water

for a stated purpose. Any physical, chemical or biological changes in surface water or groundwater that can harm living organisms or make water unfit for certain uses.

1. Direct Dischargei. Heavy metals

ii. Sewage


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iii. Industrial toxic waste

1. Diffuse Sourcesi. Acid

ii. Nitrates

iii. Pesticides

1. 10. Water related infections (EH4)A water related disease which is infectious and may be transmitted from one person to another.

Classification of Transmission Routes/Mechanisms:

1. Water borne Mechanism

Truly water borne transmission occurs when the pathogen is in water which is drunk by a

person or animal which may then become infected.

Water borne diseases include the classical infections, notably cholera and typhoid, and

also infectious hepatitis (Hepatitis A), diarrhoeas, and dysenteries.

All water borne diseases can also be transmitted by any route which permits faecal

material to pass into the mouth ie faecal oral route.

2. Water washed Mechanism

Many infections of the intestinal tract and skin may be significantly reduced following

improvements in domestic and personal hygiene, and related to increased availability and use of

increasing volumes of water for domestic and hygienic purposes.

They are known as water washed diseases, and are of three main types.

a) Firstly, there are infections of the intestinal tract, such as diarrhoeal diseases, which are

all faecal-oral in their transmission route and are therefore potentially either water-borne orwater-washed. eg bacillary dysentery (Shigellosis).

b) The second type of water-washed infection is that of the skin and eye. eg. Bacterial skin

sepsis, scabies, fungal infections of the skin and eye infections such as trachoma

c) The third type of water-washed infection is those infections carried by lice or miteswhich may be reduced by improving personal hygiene and therefore reducing the probability of


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infestation of the body and clothes with these arthropods. Examples are louse-borne typhus and

louse-borne relapsing fever.

3. Water-based Mechanism

A water-based disease is one in which the pathogen spends a part of its life cycle in a watersnail or other aquatic animal.

All these diseases are due to infection by parasitic worms (helminthes) which

depend on aquatic intermediate hosts to complete their life cycles.

An important example is Schistosomiasis, and especially common in parts ofWest Africa is Guinea worm (Dracunculus medinensis).

4. Inset Vector Route/Mechanism

The fourth and final mechanism is for water-related diseases to be spread byinsects which either breed in water or bite near water.

Examples are Malaria, Yellow fever, Dengue, Japanese Encephalitis,

Onchocerciasis (River blindness) and West African Trypanosomiasis (Gambian sleepingsickness).

1. 11. Drinking water quality (EH4)Define as carrying out physical, chemical, biological and bacteriological examinations, by takingwater samples to assess the quality of water and its suitability for particular purposes.

a) Physical quality: Depends on a number of factors. These include the amount oftotal solids

in the water, the turbidity of the water, its colour and whether there are objectionable tastes and

odours.

b) Chemical Quality: Is affected by substances which alter the potability (drinkability) of thewater supply (iron, zinc, etc.). Some chemical substances present in a water supply may affect

health (flourides and nitrates) and others are toxic and dangerous (lead, arsenic, cyanide

etc.).Standards of allowable concentrations for the above substances are given in Tables I and II.

c) Biological Quality: Growth ofalgae, protozoa and other organisms are found in most

bodies of surface water. The algae in particular are capable of rapid multiplication at certain

seasons and may cause difficulties in water supply by blocking filters and producing undesirabletaste.

d) Bacteriological quality:The bacteriological quality of drinking water is typically

expressed in terms of the concentration and frequency of occurrence of particular species of


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bacteria. Polluted water may containpathogenic bacteria, viruses, protozoa, or helminths eggs.

It is a normal practice to detect and enumerate them by 'indicator bacteria. The presence ofindicator bacteria in water is therefore indicative of faecal contamination of that water and faecal

contamination suggests the potential presence of pathogens and thus a health hazard. The most

commonly used indicator bacteria are the coliforms (gram negative, non- spore-forming rods).

Water is tested either for the presence of the total coliform group or for the presence of faecalcoliforms only. Faecal coliforms, mainly comprisingEscherichia coli, are a subgroup of the total

coliform group and they occur entirely or almost entirely in faeces. If E. coli is not found, a

further test for Streptococcus faecalis can be carried out. If S. faecalis is found, even if E. coli isabsent, then this is regarded as confirmatory evidence of pollution with sewage or faecal wastes.

e) Viral quality: The presence offree chlorine inactivates virus. In water that contains free

chlorine and in which coliform organisms are absent, virus will also generally be absent.

f) Radiological standards: Have now been formulated for the purpose of controllingradioactivity in water supplies used for drinking.

g) Biochemical indicators: May also be used as indices of water pollution e.g. the

biochemical oxygen demands (BOD) of a water sample.

1. 12. Drinking water quality surveillance (EH5)v Objectives are to raise the standard of health of the people by ensuring the safety and

acceptability of the drinking water provided to the consumer.

The key elements are:

1) Monitoring,

2) Sanitary survey

3) Data processing

4) Remedial action and

5) Institutional examination.

v In Malaysia, the various agencies are involved in drinking water supply. Water Supply

Authorities are - Public Works Department, Water Supply Department or the Water Board in

the various states.


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v The water treatment plants are usually run by the private companies to treat the raw water

from the rivers.

v Urban water supply systems are under the state water authorities, and rural water supply is

under the water authorities, Ministry of Health, and Ministry of Rural Development.

v Ministry of Health is the Surveillance Agency especially for the drinking water qualitystandards.

v The pollution of the various sources of raw water is monitored by the Department of

Environment (DOE).

v Water samples are taken from points in the water supply system which include at intake, the

treatment plant outlet, the reservoir outlet, the main pipeline as well as the rest of the distribution

inclusive of the consumer's tap.

v Simple tests are done at field by the health inspectors, and other samples are sent for furtheranalysis to the various chemical laboratories.

v Minimum number of monthly samples for piped drinking-water in the distribution system is

about 1 per 5,000 populations.

1. 13. Housing and home accidents (EH10)a) Home accidents may result from any of the following:

a defective state of repair of the house unprotected fires and defective electrical installations badly designed or located stairways' lack of storage place for inflammable materials or substances which are poisonous poor lighting

b) Mortality and morbidity statistics reveal three highly accident-prone population groups:

children, elderly people and handicapped persons.

c) Patterns of domestic accidents change with time, and there are marked differences within

and between countries.

d) The major causes of accidental injuries include falls, burns and scalds, electrocution,

suffocation, poisoning (including gassing), pedestrian accidents and bicycle accidents.

1. 14. Sanitary water supply (EH4)


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It may be considered under two headings; for small scale and large scale.

A. Purification of water on a small scale

i. Household purification of water

a. Boiling

b. Chemical disinfection: bleaching powder, chlorine solution, hypochlorite solution, tablets ofchlorine preparations "Halazone tablets", potassium permanganate, iodine solution

C. Domestic filters

ii. Disinfection of well

determine the volume of water in a well

Determine the amount of bleaching powder required for disinfection

chlorination of water

test for residual chlorine in the well water

B. Purification of water on a large scale

The principle of Conventional Treatment process is be summarised as follows:

1. 15. Food quality controla) Control at source (harvesting, slaughtering, capture)

- sanitary control of the production of the raw food item (proper handling, avoidance ofslaughtering diseased animals, proper sanitary condition of premises, equipment and utensils).

b) Control at food processing

- premises maintenance and thephysical environmentof the food processing plant (floor, walls,ceiling, vectors)

- The equipmentused in the process

- Personnel and the workers of the plant (uniforms, routine medical examinations, healtheducation)


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- The quality of raw fooditems used

- Acceptability of any additives used

- The quality of final product (quality assurance and regular checking)

c) Control at transportation and storage

-perishable foods like meat, fish, milk, vegetables, ice-cream etc. require special temperatures toprevent spoilage

d) Control at retail/distribution points

-requires the regular physical inspection and chemical analysis of food items offered for sale

e) Control at food preparation. This is especially important in terms of commercial

preparation of food as any contamination will result in a large number of people from beinginfected. In mass cooking there is also a higher chance of introducing contamination

i. Physical Environment of the Kitchen

- all surface (floor, wall ceiling) and equipment used should be clean

- free from flies and pests

- adequate water supply and utensils for washing

- raw and cooked food to be kept separately

- washing area to be separated from preparation and cooking area

- proper disposal of left-over food and refuse

ii. Food

-cooked food should not be touched by hand

-appropriate method of keeping cooked food must be used (steam table, cold table)

-must be kept away from flies and other vectors

iii.Food-handlers


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-regular medical examination to exclude carrier state and other illnesses (typhoid, cholera,

infectious hepatitis)

-education regarding good standards of personal hygiene, clothing

-education on food handling techniques

1. 16. Evaluation of food premesis (EH6)Legislation and codes of practice for the sanitary control of food and food vending are asfollows:

a. Food Act 1983, Act 281.

b. Food Regulations, 1985.

c. Code of practice for Food Hygiene, Ministry of Health, 1980.

d. Buku Panduan - Kantin Sekolah, Kementerian Pelajaran Malaysia, 1983.

e. Local Government Act, 1976, Act 171.

f. Pesticides Act, 1974, Act 149.

The purpose of registration of premises is to provide a record of the particulars such aslocation, occupier, nature of food establishments and the purposes for which they are tobe used.

Such particulars are necessary to enable proper surveillance and to make periodicassessments or evaluations of the premises at sufficiently frequent intervals.

To ensure the required degree of uniformity, the inspections and evaluations shouldbe of the same pattern and this is best achieved by using a standard report form.

The evaluation schedule for food premises adopted by the Ministry is based on theprovisions of this Code of Practice and should be used by each of the inspectors engagedin food sanitation work in all States.

The check points of inspections have beenconfined to basic requirements and theassessment of demerits reflect the opinion of the inspector, as to whether each feature is

merelysatisfactory or unsatisfactory, at the time of the inspection. Each unsatisfactory item earns a demerit of 4 points and the total when subtracted from

100 gives the rating of the premises in a percentage (%) of complete compliance with the

recommendations of this Code of Practice.

To serve as a reminder, to help anchor judgement and to achieve a desirable level ofconsistency, guidelines based on specific clauses of this Code of Practice, have been laid

down and these should be referred to when determining whether any particular feature or

check point is satisfactory or not.


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The Evaluation Schedule should not be a substitute for the detailed inspection reportfollowing the inspection of the individual food premises, but instead should complementthe report.

1. 17. Sick building Syndrome2. 18. Urban housing and health hazards (EH10)3. In addition to the appalling housing conditions, the increasing shortage of desperately

needed dwellings especially an acute shortage of housing for low-income families in

urban area, is one of the most serious problem in urban area. The urban poor bears the

greatest burden of the mismanagement of the urban environment.4. The housing problems of the metropolitan areas of the developing countries such as

scattered housing developments, mixed land use, high rents, overcrowding and

clandestine land occupancy, are also a cause for concern and action.

Contributing factors are:

rapid and uncontrolled influx of people from rural areas into towns unpreparedness of local authorities in the face of this social upheaval resulting from

industrialisation

lack of control by building authorities over exploitation by property ownersHealth Hazards associated with rapid urbanization

unplanned unsafe construction of poor quality housing

overcrowding overtaxing of public health systems -water supply, waste disposal, drainage failure of environmental services -street cleaning, refuse collection, transportation air pollution due to emissions prostitution, dependence on alcohol and drugs, increase in crime rate, social and

psychological problems.

1. 19. Rodent control methods in a community (EH9) Rodent Control Methods

o Rats cannot be eradicated, they can only be controlled. This is because there areareas where anti-rodent measures cannot be implemented -forests and jungles,

ravines, etc.

o Therefore rat control must be a continuous process.o There are two basic complementary elements to every rat control program:


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o rats must be denied access to food and harbourage (shelter), by environmentalimprovement; at the same time,

o they must be actively destroyed.

Rat killing without environmental improvements is ineffective because:o rats and mice rapidly regain the original population level through their high birth

rate and the greater survival of young as a result of less competition;

o a continuous killing program is necessary, which is costly in terms of labour andmaterials;

o continuous use of most poisons can result in resistance and bait shyness.o Three Techniques of control;

Permanent, Temporary and Naturalistic are in use against rodents.

Permanent control is the only means that can produce a lasting reductionin communal rodent numbers.

Temporary measures are necessary in the face of disease outbreaks,population eruptions and an aroused public demand for immediate action.

1. 20. House fly control (EH8)2. Flies (musca domestica) is an important mechanical vector of disease. They carry

organisms which may cause diarrhoeal diseases.

3. The Fly has filthy habits and is frequently in contact with faeces and breeds in garbage ordecomposing matter.4. Fly control is primarily a matter ofgood excreta and garbage (waste) disposal.

5. In urban areas, it is affected by proper removal and disposal of garbage and sewage.6. In rural areas, unsanitary latrines, undisposed animal excreta and other refuse tend to

promote breeding of flies.

7. Elimination of breeding places is the most effective and satisfactory method of control.8. Fly Control Measures

i. Elimination of breeding places e.g. improvement ofenvironmental sanitation especially refuse and sewage disposal.

ii. Prevention of entry e.g. wires gauze proofing.

iii. Trapping e.g. use of cords and strips impregnated

with insecticides.

iv. Manual killing

v. Baiting e.g. by using poisoned baits, solid or liquid.


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vi. Insecticide spray e.g. residual spray, space spray.

vii. Health education e.g. create a "fly consciousness"

among people.

1. 21. Public health importance of rodents (EH9) Rodents are animals with strong incisors and no canine teeth (e.g. rat, squirrel, beaver).

Public health importance of Rodents

Rats and other rodents are the reservoir and source of several diseases of man, eitherdirectly (as by biting, or contamination of human food with their urine or faeces), orindirectly (by way of fleas and mites).

Rat-bites create a serious health problem and are far more common than most peoplerealize. Helpless infants and defenseless adults (invalids or unconscious persons) are

particularly subject to attack.

1. 22. Aedes control methods (EH8)a. Source reduction

remove/reduce non-essential water containers receptive to mosquito breeding

avoid/protect water storage containers from larval breeding by proper covering environmental sanitation reduce water storage containers by provision of pipe water supply regular changing of water in household receptacles once a week

b. Larviciding

use of larvicide; Abate I % sand granules or temephos 10 gm per kg especially in high-risk localities before outbreaks are expected, to be put into water storage drums, flower

vases, ant-traps etc.

biological control by keeping Larvivorous fish like Gambushia.1. Anti-adult mosquito measures (adulticiding) focal spray (Thermal Fogging)

Focal spray is carried out by using thermal fogging machine such as swing fog (hand-held type)for a radius of 200 meters around the house of the patient reported to have Dengue or Dengue


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Haemorrhagic Fever. Suitable insecticide such as Malathion, Resilin, Sumithion and Aqua-

resigen pyrethroid are used.

Repeat fogging after 7- 10 days is necessary.

ULV spray (Ultra Low Volume Fogging)

For a locality having an epidemic outbreak (more than 1 case within 14 days), vehicle-mounted

ULV cold aerosol fogging machine spraying is done to carry out the rapid adulticide operation

covering an area of about 20 square kilometers. Repeat after 7-10 days.

Preventive fogging can be done in high Aedes Indices areas with the same method.

1. Health education and community participation2. Legislation and Law Environment

v The main legislation empowering the health authorities to take action in the control ofarthropods is the "Destruction of Disease-Bearing Insects Act" (DDBIA) of 1975 (Act 154). This

Act defines 'a disease-bearing insect'as "any insect carrying or causing or capable of causing,any disease of human beings or domestic animals, and includes the eggs, larvae and pupae of

such insect".

v Medical Officers of Health and Health Inspectors are given powers of entry and seizure under

this Act. They are also empowered to cause certain works to be carried out by the occupier of abuilding. Penalties for non-conformance are also prescribed. The Ministry of Health has aVector-borne disease Control Program which deals with the control of vector-borne diseases in

Malaysia and this is the section which will enforce the Destruction of Disease Bearing Insect

Act.

1. Vector SurveillanceVector surveillance is one of the activities in the control of dengue and dengue haemorrhagic

fever. The following are the indices used to monitor Aedes aegypti population in terms of vector

density in dengue transmission.

Ovitrap index (egg sampling)

1. 23. Malaria prophylaxis (EH8)a. Anti-larval Measures


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i. Elimination of breeding places (source reduction) -It includes permanent measures of

environment such as:

a) Filling of low lying places where water may accumulate. This is particularly important for

controlling breeding of Anopheles.

b) Weekly emptying of household collections of water, particularly to prevent breeding ofAedes.

c) Covering of drains, ditches, cess pools and sewers near the houses, where Culex breeds.

d) Removal of vegetation on shores of slow moving streams where A. fluviatilis breeds.

e) Removal of water plants such as Pistia Stratiotes and water hyacinth, manually or by

herbicides, checks the breeding of Mansonia.

ii. Larvicidals

a) Mineral Oils: Kerosene, diesel, fuel oil and malariol are used for this purpose.

b) Paris green (copper acetoarsenite): it is used to kill surface feeding of anopheline larvae. Itis dusted at the rate of 840 g/ha (one hectre = 10000 sq m) of surface.

c) Synthetic insecticides: Most larvicides are organophosphorus compounds like

chlorpyriphos, fenthion and Abate, which quickly hydrolyse in water.

Abate (500E emulsion) is the least toxic of these and is very effective at concentration of 1 ppm.

iii. Biological control

v Some fish (Gambusia affinis and Lebister recticulatus) are known predators of mosquito

larvae.

v They may be introduced into tanks, lakes, farms and oxidation ponds for this purpose.

v Bacillus thurengesis, a biological larvicide can also be introduced.

B. Surface or residual spray:

In this method, a slow acting insecticide with prolonged residual effect such as (DDT), BHC,Dieldrin etc. is sprayed on floor, walls and other surfaces where it kills the resting insects. This

could be in the form of:

regular spraying focal spraying special spraying


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For Aedes, (DDT 3.5%), dieldrin 1%, lindane 1%, malathion 2.5% and fenthion 1 % can be used

as emulsion or suspension.

For Mansonia, in addition to insecticides, herbicides have to be used to destroy the weeds whose

roots support the larvae.

C. Genetic control:

Males sterilised by gamma irradiation and chemosterilants are released. They mate with females but the latter produce unfertilized eggs which do not develop

further.

This is a potentially useful method that has yet to be tried on a large scale.D. Prevention of Mosquito Bites:

a) Use of repellents: Diethyl toluamide (deet) and butyl ethyl propanediol applied on clothes

repels culex for 6-1.3 hours. Others in use are DMP, indalone, dimethyl carbate and ethylhexanediol. They are applied to the exposed parts of the body

b) Preventing entry into houses: Mosquito- proof wire gauze is used on doors, windows and

ventilators.

c) Sleeping in mosquito nets: using insecticide impregnated bed-nets (with permethrin), and

using veils, socks and gloves etc. as necessary.

E. Personal Protection

drug prophylaxis : 1 week before until 4 weeks after leaving the malaria endemic area bytaking Chloroquine 2 tablets with Fansidar 1 tablet every week.

mechanical measures to reduce man-mosquito contact (nets, clothing, repellants) health education possibility of vaccines

F. Anti-parasite measures

effective treatment of cases e.g. in falciparum, and radical treatment to prevent relapse invivax and ovale malaria

mass blood survey and case finding (active and passive) in malaria

G. Law enforcement


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Prevention and Control of Infectious Diseases Act, 1988 Destruction of Disease Bearing Insects Act, 1975 (DDBIA)

H. Health education and community participation

health education is one of the most effective and satisfactory method of control of vector-borne diseases.

community participation is essential in ensuring continuous hygienic measures in thecontrol of vector-borne diseases.

h. Integrated Vector Control

practical application of a combination of several feasible methods to control vectors asmentioned above.

1. 24. Air pollution (EH7)Definition: When potentially noxious substances are discharged into the atmosphere at a rate that

exceeds its capacity to disperse them by dilution and air currents, the resulting accumulation is

air pollution.

a) Types of Air Pollutants Air pollutants may be gaseous or particulate in nature, andparticulates may be either solid or liquid.

1. Gaseous Pollutants : These are derived from materials which have entered into chemicalreactions or combustion processes.

They include;

1. carbon-based compounds like hydrocarbon, oxides and acids,2. sulfur compounds such as dioxide, trioxide and sulfides,3. nitrogen compounds (ammonia, amines, oxides) and4.

halogenated substances (organic and inorganic halides)5. Particulates

i. Particle or droplet size may range

from 0.01 to 100 mm in diameter.

ii. The smaller particles are referred to

as aerosols and can remain suspended, scattering and behaving much like a gas.


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iii. Below 10 mm particles are capable of

penetrating to all sites in the respiratory tract.

iv. Industrial particulates are usually

solid and are carbonates, metallic oxides, salts or acids and their porosity is such that they will

absorb other gases and liquids.

b) Smog

1. It is a combination of smoke and fog and is a popular term for a mixture of gaseous andparticulate pollutants that accumulate over urban centers and persists for a prolonged

period.

2. Smog is a brown or yellow haze, and it usually occurs as a phenomenon to temperatureinversion when a high-level mass of cold air traps warmer air beneath it to preventmixing and dispersion.

3. E.g. London Smog (fog) in 1952 lasted over a week and causes about 4,000 deaths,mostly from respiratory diseases.

c) Haze

1. Haze consists of sufficient smoke, dust, moisture, and vapour suspended in air to impairvisibility.

2. The term regional haze means haze that impairs visibility in all directions over a largearea.

3. .g. Forest fire and Regional Haze in South-east Asia 1997.d) A. Sources

1. Naturally occurringi. SO2 - Volcanoes

ii. Methane - Agriculture

iii. PAH (polynuclear aromatic

hydrocarbons) etc. - Forest fires

iv. CO2 - Lake Nyos, Cameroon

1. Combustioni. Stationary sources - Power

production, Industrial, Fossil fuel, Waste treatment, Agriculture, Nature, Open burning

ii. Mobile sources - Road transport, Off-

road mobile sources -CO, NO2, SO2, Hydrocarbons


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1. Chemical production and its usei. Hydrocarbons

ii. Halogenated hydrocarbons

(Chloroflorocarbons - CFC etc.)

1. Atmospheric chemical reaction (Secondary pollutants)i. Ozone from NOx and hydrocarbons

1. Waste treatmenti. Burning (Incinerators) - Dioxin, PAH

etc.

ii. Land fills - Methane organics

e) Health Effects

Acute Effects

i. Short-term exposure to hazardouslevels of air pollutants may result in irritation to the eyes and the respiratory tract,

ii. Populations at high risks include thevery young and the elderly, whose respiratory and cardiovascular systems are not fully

functional, people with asthma, emphysema, heart diseases, and heavy smokers

Chronic Effects

iii. Long-term exposure to lower levels of

pollution may result in, or aggravate, chronic bronchitis, pulmonary emphysema, bronchial

asthma and lung cancer.

iv. Cigarette smoke will cause all these

problems.

v. Dust and other allergens, includingpollen, 1-90 mm in diameter, can induce or trigger allergic reactions in susceptible people.

Essays & problem Solving type questions (20marks)


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1. 1. Relationship between housing and health in a community. (EH10)a. Housing and Rate of Sickness:

It is a common observation that there is a higher rate of sickness in a poorly-housed population

than in a well-housed one. But a clear cut cause and effect relationship is difficult to establish forthe following reasons:-

i. Housing (residential environment) embraces many facets of the

total environment, each influencing health in a separate and sometimes different manner; e.g. badsanitary conditions may cause disease, while inadequate illumination affects vision and may

foster an increase in home accidents.

ii. Many other socio-economic factors which influence health may

accompany poor housing; poverty, ignorance, poor nutrition and lack of medical care.

iii. Lack of understanding of the unit of population that should be usedas the basis for measurement; e.g. should it be the individual, the household, the community or

any other unit.

iv. There is no unified system of measurement of the hygienic quality

of housing on the residential environment.

b. Effects of Poor housing Conditions

i. Physiological and Psychological

It may not fulfill his physiological or psychological needs: or undue stress may be placed on thecorresponding responses:

excessive noise, cold, heat or dampness noxious odours poor lighting lack of privacy for the family or for the individuals within the family1. Disease Transmission

It may encourage disease transmission:

overcrowding and/or poor ventilation inadequate or contaminated water supply defective sewage disposal system infestation with vermin attraction of insects communicable disease


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iii. Home Accidents (Domestic Accidents)

Home accidents may result from any of the following:

a defective state of repair of the house

unprotected fires and defective electrical installations badly designed or located stairways' lack of storage place for inflammable materials or substances which are poisonous poor lighting

Mortality and morbidity statistics reveal three highly accident-prone population groups:

children, elderly people and handicapped persons.

The major causes of accidental injuries include falls, burns and scalds, electrocution, suffocation,

poisoning (including gassing), pedestrian accidents and bicycle accidents.

iv. Social well-being and Mental Health

There is a relationship between good housing and good mental health and bad housingand poorer mental health.

Many aspects of housing, such as crowded housing, excessive noise, sharedaccommodation, oppressive landlords, bad smells and dampness, give rise toconsiderable dissatisfaction, annoyance and stress, and may perhaps contribute to thedevelopment of interpersonal conflicts.

v. Pollution and Residential environment

Water pollution Air pollution Soil & dust pollution

1. 2. Principles of prevention and control of aedes mosquitoes in urban areas ofMalaysia. (EH9)

a. Source reduction

b. Larviciding

1. Anti-adult mosquito measures (adulticiding) focal spray (Thermal Fogging)

o ULV spray (Ultra Low Volume Fogging)


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1. Health education and community participation2. Legislation and Law Environment3. Vector Surveillance

1. 3. Adult control and larval control. (EH9)2. 4. Methods of control of malaria vectors in Malaysia (EH9)

a. Anti-larval Measures

i. Elimination of breeding places (source reduction) -It includes permanent measures ofenvironment such as:

ii. Larvicidals

iii. Biological control

B. Surface or residual spray:

This could be in the form of:

regular spraying focal spraying special spraying

C. Genetic control:

D. Prevention of Mosquito Bites:

a) Use of repellents

b) Preventing entry into houses

c) Sleeping in mosquito nets

E. Personal Protection

drug prophylaxis

mechanical measures to reduce man-mosquito contact health education possibility of vaccines

F. Anti-parasite measures

effective treatment of cases


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mass blood survey and case finding (active and passive) in malaria

G. Law enforcement

Prevention and Control of Infectious Diseases Act, 1988 Destruction of Disease Bearing Insects Act, 1975 (DDBIA)

H. Health education and community participation

h. Integrated Vector Control

1. 5. Principles of air pollution control in urban areas of Malaysia. (EH7)A. Specific

1. Process substitution2. Prevention of release at source3. Treatment of release at source4. use of non waste technology5. Waste management policy

Centralised Decentralised1. Environment monitoring

B. General

Governmental

1. Laws and Enforcement e.g. Environmental Quality Act 1987.2. Environmental Impact Assessment (EIA) procedures.3.

Land use planning and zoning for housing and industries4. Regulations to control emission of pollutants

5. Public Education and awareness6. Environmental monitoring by Ministry of Environment, Science and Technology,

Ministry of Health, Ministry of Agriculture, Ministry of Industry etc.

7. International collaboration with WHO and other countries.Non Governmental


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1. Non Governmental Organizations (NGOs).2. Community participation

1.

6. Water related infections and transmission mechanisms, and their prevention.

Classification of Transmission Routes/Mechanisms:

1. Water borne Mechanism

Truly water borne transmission occurs when the pathogen is in water which is drunk by aperson or animal which may then become infected.

2. Water washed Mechanism

Many infections of the intestinal tract and skin may be significantly reduced followingimprovements in domestic and personal hygiene, and related to increased availability and use ofincreasing volumes of water for domestic and hygienic purposes.

They are known as water washed diseases, and are of three main types.

a) Firstly, there are infections of the intestinal tract,

b) The second type of water-washed infection is that of the skin and eye.

c) The third type of water-washed infection is those infections carried by lice or mites

3. Water-based Mechanism

A water-based disease is one in which the pathogen spends a part of its life cycle in a water

snail or other aquatic animal.

4. Inset Vector Route/Mechanism

The fourth and final mechanism is for water-related diseases to be spread by insects whicheither breed in water or bite near water.


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Prevention:

a) Improve quality of drinking water

b) Prevent casual use of other unimproved sources

c) Increase water quantity used

d) Improved accessibility and reliability of domestic water supply

e) Improve hygiene

f) Decrease need for contact with infected watera

g) Control snail populationsa

h) Reduce contamination of surface waters by excretab

i) Improve surface water management

j) Destroy breeding sites of insects

k) Decrease need to visit breeding sites

l) Use mosquito netting

1. 7. Poor housing conditions and health problems and how to prevent them. (EH10)--Housing condition & health problem refer Q1

Housing can be improved in the following ways;

a. Continuous Maintenance Inspection and Control

This involves the periodic official inspection of housing to encourage owners, managers and

occupants to maintain as high standards of sanitation, repair and occupancy as may be

practicable.

b. Conservation

This is a more formal and systematic programme, usually in areas that have not become seriously

substandard, designed to ensure that substandard properties are kept in an acceptable condition.

c. Rehabilitation


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This is a program for removing individual grossly unfit housing units and bringing all units into

compliance with a good housing code.

d.Redevelopment

This consists in the re-planning and rebuilding of areas in which housing or environmentalconditions or both are so far below standard that ordinary repair and rehabilitation would notproduce satisfactory results.

e. Slum clearance and Rehousing

This is a program for improvement of squatter or slum settlements in the same place or at adifferent location to meet an acceptable health standard, with the active participation of the

community.

1. 8. Food quality control measures in Malaysia.2. 9. Drop latrine in a riverine community and anticipated health problems and how

to improve the situation.

10. Sanitary methods of final solid waste disposal. (EH2)

1. DumpingCan be either open dumping or dumping at sea.Open dumping: Refuse is dumped into low-lying areas. Hauling is the only cost, and therefore a

cheap method of refuse disposal. It is widely practiced, but is a very insanitary method.

Dumping at sea: Practiced in coastal areas and islands, and may be used as a method of land

reclamation.

b. Controlled tipping - this is a satisfactory method of refuse disposal where suitable land is

available.

It differs from ordinary dumping is that the solid waste is placed in a trench or other preparedarea, adequately compacted, and covered with a layer of earth at the end of each day's operation

or at such more frequent intervals as may be necessary

c. Sanitary Landfill

Ideally, a sanitary landfill site should be on inexpensive land within economical haulingdistance, have year-round access, and be at least 1,500 m downwind from residential and

commercial neighbors.

Preparation of the site involves fencing, grading, stockpiling of cover material,construction of beams, landscaping, and the installation of leachate collection and

monitoring systems.


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Wells for gas collection may also be provided. Landfill liners are natural or syntheticmaterials used to line landfills so that leachate cannot leach into the groundwater.

d. Composting

A method of combined disposal of refuse and night soil or sludge, in which organic wasteis converted to useful manure. The organic content of refuse is converted into compost, ahumus-like material soil conditioner which can improve the fertility and structure of

agricultural soils.

Methods include:

o Bangalore method (anaerobic) - layers of refuse and night soil are altered and toplayer is covered with earth.

o Mechanical composting (aerobic)All reusable material is savaged from therefuse, and remnant is then pulverized


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i. Mechanical size-reduction - can be done before the final disposal by the following methods;

Separation, Pulverization(crushing), Maceration(soaking), Grinding, Baling(packaging),Compaction

j. Integrated Waste Management - The concept of an integrated waste management is derivedfrom the broad-based environmental and resource conservation concerns which incorporateswaste reduction, reusing materials, recycling and only finally, disposal either by incineration,

sanitary landfill or composting.

11. Sources of air pollutants and health hazards.

1. Naturally occurring2. Combustion

i. Stationary sources

ii. Mobile sources

1. Chemical production and its usei. Hydrocarbons

ii. Halogenated hydrocarbons (Chloroflorocarbons -CFC etc.)

1. Atmospheric chemical reaction (Secondary pollutants)i. Ozone from NOx and hydrocarbons

1. Waste treatmenti. Burning (Incinerators) - Dioxin, PAH etc.

ii. Land fills - Methane organics

Health Effects

Acute Effects

i. Short-term exposure to hazardous levels of air pollutants may

result in irritation to the eyes and the respiratory tract,


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ii. Populations at high risks include the very young and the

elderly, whose respiratory and cardiovascular systems are not fully functional, people withasthma, emphysema, heart diseases, and heavy smokers

Chronic Effects

i. Long-term exposure to lower levels of pollution may result in,or aggravate, chronic bronchitis, pulmonary emphysema, bronchial asthma and lung cancer.

ii. Cigarette smoke will cause all these problems.

iii. Dust and other allergens, including pollen, 1-90 mm indiameter, can induce or trigger allergic reactions in susceptible people.

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