pharmacy

Public Health, Health Education & Disease Prevention

A comprehensive guide to public health and health education, covering core concepts of health and disease, epidemiology, environmental factors, nutrition, demography, microbiology, and the prevention and control of communicable and non-communicable diseases, alongside essential skills like disinfection and arthropod control.

Introduction to Health Education and Community Pharmacy

Health Education

  • Definition: A process that informs, motivates, and helps people adopt and maintain healthy practices and lifestyles, advocates environmental changes, and conducts professional training and research to this end.
  • Main Objectives:
    • Informing the people: Disseminating scientific knowledge, removing ignorance, prejudices, misconceptions, and superstitions about health and disease.
    • Motivation of the people: Encouraging changes in detrimental habits (e.g., outdoor defecation, polluted water use, drinking, smoking, drug abuse, physical inactivity, family size) and adopting healthy practices.
    • Guidance of the people: Helping people adopt and maintain healthy practices, guiding judicious use of health services (e.g., timely immunization, family planning, safe drinking water, rehabilitation).
  • Components of Health Education:
    • Knowledge about the human body.
    • Nutrition and balanced diet.
    • Personal and environmental hygiene.
    • Family health (mother and child care, family planning, immunization, elderly care).
    • Control of communicable and noncommunicable diseases.
    • Mental and social health.
    • Prevention of accidents and first aid.
    • Proper use of available health services.

Pharmacist and Public Health

  • Shift in Focus: With global population rise, pharmacists’ attention has shifted towards the patient, their environment, and general well-being, de-emphasizing product-oriented skills.
  • Areas of Active Involvement:
    • Drug-related problems: Counselling on proper use of OTC and prescribed medications, taking drug/medical histories, patient referral, immunization schedules, adherence advice.
    • Pharmacoepidemiology: Safety and risk assessment of new drugs, post-marketing surveillance, monitoring associated risks and ADRs, generating information on pharmaceutical outcomes.
    • Communicable diseases: Awareness of natural history, patient referral, public education (e.g., safe sexual practices, condom use, AIDS prevention).
    • Chronic disease control: Encouraging proven prevention techniques (e.g., good living habits, moderate exercise for cardiovascular diseases, blood pressure control for strokes), promoting smoking cessation, lower cholesterol intake, physical activity, and health consciousness.
    • Health education: Providing pamphlets/bulletins on diseases, drug classes, drug abuse, drug-food interactions, STDs, immunizations, family planning, poison prevention, environmental protection, workplace safety. Actively imparting professional information through person-to-person contact.
    • Maternal and child health: Early diagnosis of pregnancy, informed supervision through delivery and postpartum, infant care (first year of life).
    • Nutrition: Advising on basic food needs, correcting improper habits, special nutrient requirements (pregnancy/maternity), diabetic diet instructions, supporting school lunch programs.
    • Environmental health: Alertness to community conditions, control of hazards (air/water pollution, food-borne diseases), awareness of occupational hazards (e.g., asbestos industry workers prone to lung cancer).
    • Alcoholism and drug abuse: Helping dependent individuals, advising local agencies about drugs and harmful effects, prevention of alcoholism and drug abuse.
  • Key Involvement Areas in Community Pharmacy:
    1. Drug and Nutrition Counselling.
    2. Proper use of Prescribed and OTC Drugs.
    3. Family Planning.
    4. Pregnancy and Infant Care.
    5. Immunizations.
    6. Sexually Transmitted Diseases.
    7. Control of Toxic Agents.
    8. Occupational Health and Safety.
    9. Control of Accidental Injuries.
    10. Fluoridation of Community Water Supplies.
    11. Smoking Cessation.
    12. Reduction of Misuse of Alcohol and Drugs.
    13. Improved Nutrition.
    14. Environmental Protection.
    15. Programmes on Weight Control.
    16. Poisoning and Cancer Signals.
  • Indian Context: Involvement is minimal currently but expected to significantly increase with pharmacist education and public awareness.

Concepts of Health and Disease

Definition of Health

  • WHO (1948) Definition: “Health is a state of complete physical, mental and social well-being and not merely as absence of disease or infirmity”.
  • Expanded Definition: Includes the ability to lead a “socially and economically productive life”.

Operational Definition of Health

  • Broad Sense: A condition or quality of the human organism expressing adequate functioning in given generic or environmental conditions.
  • Narrow Sense (Measurable):
    • No obvious disease evidence, normal functioning within accepted health criteria for age, sex, community, geographic region.
    • Adequate functioning of body organs individually and in relation to one another (equilibrium or homeostasis).

Dimensions of Health

  • Physical Dimension: Perfect functioning of the body, optimal capacity of every cell/organ, harmony within the body. Signs include good complexion, clear skin, bright eyes, lustrous hair, firm flesh (not obese), sweet breath, good appetite, sound sleep, regular bowel/bladder activity, well-coordinated movements, normal organ size/function, intact special senses, normal resting pulse/BP, and exercise tolerance for age/sex.
  • Mental Dimension: (Not explicitly detailed in provided text).
  • Social Dimension: (Not explicitly detailed in provided text).
  • Spiritual Dimension: Component of thinking striving for meaning/purpose in life; includes integrity, principles, ethics, commitment to a higher being, and belief in concepts beyond “state of the art” explanation.

Determination of Health (Factors Influencing Health)

  • Heredity: Physical/mental traits determined by genes. Genetic origin for diseases like epilepsy, diabetes, cancers, abnormal drug responses (e.g., succinylcholine apnea, isoniazid acetylation, haemolysis by antimalarials, hepatic porphyrias by barbiturates).
  • Environment: Direct influence on physical, mental, social well-being. Factors include housing, water supply, air, noise, psychological stress, family structure, social/economic support, and health/social welfare services.
  • Life Style: Way people live, reflecting social values, attitudes, and activities. Cultural/behavioural patterns, personal habits (smoking, alcoholism). Linked to health problems (coronary heart disease, obesity, lung cancer, drug addiction) and health promotion (nutrition, sleep, physical activity).
  • Socio-economic Conditions: Significant influence on health. Factors include:
    • Economic Status: Per capita GNP, purchasing power, standard of living, quality of life, family size, healthcare attention. Affluence can also contribute to illness (e.g., coronary heart disease, obesity, diabetes in upper groups).
    • Education: Influences health status. Illiteracy linked to poverty, malnutrition, ill health, high infant mortality. Education compensates for poverty’s effect on health (e.g., Kerala’s female literacy rate).
    • Occupation: Productive work promotes health; job satisfaction for mental health; generates income, raises economic status.
    • Political System: Shapes health through resource allocation, manpower policy, technology choice, environmental protection, accessibility of health services.
  • Health Services: Purpose is to improve population health status (e.g., safe water, healthy environment, screening, immunization, nutritional care). These components form primary health care.

Indicators of Health

  • Purpose: Measuring community health status, comparing countries, estimating healthcare requirements, allocating resources, monitoring/evaluating services, and assessing programme objectives/targets.
  • Requirements: Scientifically relevant and dependable, including validity, reliability, sensitivity, and specificity.
  • Classification (WHO Categories):
    • Health Policy Indicators: Proportion of GNP spent on health services, health-related activities (water supply, sanitation, housing, nutrition), and primary health care.
    • Social and Economic Indicators Related to Health: Population increase rate, per capita GNP, unemployment, dependency ratio, literacy rate, family size, housing (persons per room), per capita calorie availability.
    • Indicators for Provision of Health Care: (Not explicitly detailed as a separate heading beyond health policy indicators).
    • Health Status Indicators:
      • Mortality Indicators: Crude death rate, expectation of life (global indicator, 60 years by 2000 AD goal), infant mortality rate (universally accepted, sensitive, 50/1000 by 2000 AD goal).
      • Morbidity Indicators: (Not explicitly detailed in provided text).
      • Disability Indicators: (Not explicitly detailed in provided text).
      • Nutritional Status Indicators: (Not explicitly detailed in provided text).
      • Health Service Indicators: (Not explicitly detailed in provided text).
      • Environmental Indicators: Quality of physical/biological environment (air/water pollution, radiation, solid wastes, noise, toxic substances in food/drinks).

Concept of Disease

  • Definition: “A condition of the body or some part or organ of the body, in which its functions are disrupted or deranged” (Oxford English Dictionary). Also defined ecologically as maladjustment of human organism to environment, or opposite of health.
  • Manifestations: Inapparent (subclinical) to severe symptoms, acute (asthma) or insidious (rheumatism) onset, carrier state (e.g., amoebiasis, typhoid), same organism causing multiple manifestations, same disease from multiple organisms (e.g., diarrhoea). Outcomes vary: recovery, disability, death.

Causation of Disease

  • Germ-theory of Disease: One-to-one relationship between agent and disease; now understood as multifactorial.
  • Epidemiological Triad: Agent, host factors, and environment in disease causation (e.g., TB exposure in undernourished person in unhygienic conditions).
  • Multifactorial Causation: For modern diseases (lung cancer, CHD, chronic bronchitis, mental illness) not attributed to single infective organisms. Factors include smoking, fat intake, lack of exercise, obesity, drugs, linked to lifestyle/behaviour.

Natural History of Disease

  • Definition: The way a disease evolves from prepathogenesis to full-blown development, signs/symptoms, and termination (recovery, disability, or death).
  • Phases:
    • Prepathogenesis Phase: (Not explicitly detailed as a separate heading, but covered by the overall description of disease factors).
    • Pathogenesis Phase: Begins with agent entry into susceptible host, multiplication, tissue/physiological changes, incubation, early/late pathogenesis. Modified by intervention (immunization, chemotherapy). In non-infective chronic diseases, early phase is “presymptomatic”.

The Disease Agents

  • Biological Agents: Living agents causing infections/communicable diseases (bacteria, viruses, fungi, protozoa, metazoa, rickettsiae). Exhibit infectivity, pathogenicity, virulence.
  • Nutritional Agents: Carbohydrates, fats, proteins, vitamins, minerals. Responsible for deficiency diseases (malnutrition, anemia, scurvy) or diseases from excess intake (hypercholesterolemia, obesity, goitre).
  • Physical Agents: Heat, cold, humidity, pressure, radiation. Excessive exposure causes illness.
  • Chemical Agents:
    • Endogenous: Produced in body from metabolic derangement (urea, bilirubin, ketones, uric acid, calcium carbonate) causing uremia, jaundice, ketosis, renal stones.
    • Exogenous: From environment (allergens, metals, fumes, dusts, gases, insecticides) causing acute/chronic diseases.
  • Mechanical Agents: Chronic friction, vibrations causing injury, sprains, tearing, dislocation, stress, or fatality.
  • Social Agents: Poverty, smoking, drug/alcohol abuse, unhealthy lifestyles, social isolation, maternal deprivation.

Concept of Prevention of Diseases

  • Objective: Intercept or oppose the “cause” of disease. Treatment is included as an intervention method.
  • Levels of Prevention:
    • Primary Prevention: Measures prior to disease onset to ensure it never occurs. Achieved by promoting general health, specific protective measures. Applied to chronic diseases by eliminating/modifying risk factors.
      • Primordial Prevention: Primary prevention in its true sense (implicitly about preventing risk factors from emerging).
      • High Risk Strategy: Preventive care for high-risk individuals detected by clinical/diagnostic methods.
      • Utilises knowledge of prepathogenesis phase (agent, host, environment). Safety and negligible cost justify wider application; synonymous with health education.
    • Secondary Prevention: Halts disease progress at incipient stage, prevents complications. Interventions: early diagnosis, adequate treatment. Arrests disease, restores health, reverses communicability. Largely clinical medicine domain. More expensive and less effective than primary prevention.
    • Tertiary Prevention: Intervention in late pathogenesis phase. Reduces impairments/disabilities, minimises suffering, promotes patient adjustment to untreatable conditions. Extends to rehabilitation.

Epidemiology

Scope of Epidemiology

  • Definition: Study of disease frequency, distribution, and determinants in human populations.
  • Components:
    • Disease Frequency: Measurement of disease, disability, or death using rates/ratios (prevalence, incidence, death rates). Essential for comparing populations and clues to etiology.
    • Distribution of Disease: Pattern of disease distribution in relation to time, place, and person. Examines increases/decreases over time, higher incidence in specific geographies, gender/age group differences, host characteristics. Contributes to etiological hypothesis formulation (“descriptive epidemiology”).
    • Determinants of Disease: Testing etiological hypotheses, identifying underlying causes/risk factors (“analytical epidemiology”). Helps develop health programmes, interventions, policies.

Aims of Epidemiology (International Epidemiological Association)

  1. Describe the distribution and size of disease problems in human populations.
  2. Identify etiological factors in the pathogenesis of disease.
  3. Provide data essential for planning, implementation, and evaluation of prevention, control, and treatment services, and setting priorities.

Epidemiological Methods

  1. Descriptive Epidemiology: Concerned with disease/health-related characteristics distribution in human populations.
    • Procedures: Defining population/disease, describing distribution (time, place, person), measuring disease (mortality, morbidity, disability), formulating etiological hypothesis.
    • Information provided: Magnitude/type of disease problems, clues to etiology (e.g., smoking and lung cancer), background data for planning/evaluating services.
  2. Analytical Epidemiology: Tests etiological hypotheses. (Cohort and Case-Control studies are major types).
    • Case-Control Study: Group with outcome compared to group without; exposure rates compared via odds ratio.
    • Cohort Study: (Definition not explicitly provided but implies group sharing common characteristic/experience studied forward from cause to effect).
  3. Experimental Epidemiology: Provides scientific proof of etiological factors, measures effectiveness/efficiency of health services.
    • Types: Randomized controlled trials (RCTs), Non-randomized/non-experimental trials.

Uses of Epidemiology

  1. Study of the history of disease pattern in the population (fluctuations, identification of new diseases like AIDS).
  2. Community diagnosis: Identifying/quantifying health problems, defining at-risk groups, setting priorities, evaluating health services, providing new knowledge.
  3. Planning and evaluation: Fundamental basis for developing health services and evaluating their effectiveness.
  4. Evaluation of Individual’s risks: Predicting risk, assessing causal association (e.g., smoker’s lung cancer risk, hypertensive’s CHF risk).
  5. Identification of syndromes: Defining syndromes by frequently associated findings.
  6. Completing the natural history of disease: Broad perspective of disease in the community, filling gaps.
  7. Search for risk factors: Establishing causes/risk factors for chronic/acute diseases (e.g., thalidomide teratogenicity, smoking and lung cancer).

Dynamics of Disease Transmission

Reservoir or Source of Infection

  • Starting Point: Existence of reservoir or source from which infectious agent is disseminated.
  • Reservoir Definition: Any person, animal, arthropod, plant, soil, or substance where infectious agent survives and multiplies for transmission. Source and reservoir may not be synonymous (e.g., typhoid patient is reservoir, feces is source).
  • Types of Reservoirs:
    • Human Reservoir: Most important. May be a case (person with disease, identified by signs/symptoms, confirmed by diagnostic methods) or a carrier (infected person harboring agent without clinical disease, potential source of infection).
    • Animal Reservoir: (Not explicitly detailed beyond mention of zoonoses).
    • Non-living Reservoir: (Not explicitly detailed).

Routes of Transmission

  • Depend on infectious agent, portal of entry, ecological conditions. Most diseases by one route, some by more (e.g., hepatitis B, AIDS).
  • Direct Transmission: Direct, immediate transfer from source to susceptible person.
    • Direct Contact: Skin-to-skin (touching, kissing, sexual intercourse) e.g., syphilis, gonorrhoea, AIDS, leprosy, conjunctivitis, skin infections.
    • Droplet Infection: Minute droplets of saliva/nasopharyngeal secretions spread during sneezing/coughing/talking (30-60 cm distance). E.g., common cold, diphtheria, whooping cough, tuberculosis, meningococcus meningitis. Increased risk with close proximity, overcrowding, poor ventilation.
    • Contact with Soil: Direct exposure of susceptible tissue to agent in soil, compost, decaying matter. E.g., hookworm, tetanus, mycosis.
    • Bite of an Animal: E.g., rabies.
    • Transplacental Transmission: Through placenta. E.g., syphilis, hepatitis B, AIDS.
  • Indirect Transmission:
    • Vehicle-borne Transmission: (Not explicitly detailed as a distinct subsection but implied by water/foodborne diseases).
    • Vector-borne Transmission: Arthropod or living carrier transports agent. E.g., malaria, plague, filariasis, schistosomiasis, encephalitis.
    • Air-borne Transmission: Via “droplet nuclei” (dried droplets, 1-10 micron, remain airborne, retain virulence) or dust.
      • Droplet nuclei: E.g., tuberculosis, influenza, chickenpox, measles.
      • Dust: Larger droplets settle on surfaces; infectious agents in dust. E.g., pneumonia, tuberculosis, Q fever, streptococcal/staphylococcal infections. Common in hospital-acquired (nosocomial) infections.
    • Fomite-borne Transmission: Fomites (articles/substances) contaminated by pathogens. E.g., typhoid, diphtheria, bacillary dysentery, hepatitis A, eye/ear infections (soiled clothes, towels, cups, toys, door handles).
    • Uncleaned Hands and Fingers: Most common medium for transfer from skin, nose, bowel, food. E.g., staphylococcal/streptococcal infections, typhoid, dysentery, hepatitis, intestinal parasites. Implies lack of personal hygiene.

Immunity and Immunization

  • Immunity: Resistance by host to injury from microorganisms and products. Protection against infectious diseases is a consequence of immune response.
  • Immunization: Providing immunity using an immunizing agent.
    • Active Immunization: Uses vaccines and toxoids. Stimulates protective antibody and other immune mechanisms.
      • Live vaccines: From live, attenuated organisms (e.g., BCG, measles, oral polio). More potent than killed vaccines.
      • Vaccination schedule (Universal Immunization Programme - EPI): Diphtheria, whooping cough, tetanus, polio, tuberculosis, measles. At birth: BCG, Oral Polio. 6, 10, 14 Weeks: DPT, Oral Polio. 9 Weeks: Measles.
    • Passive Immunization: Uses antisera and immunoglobulins (normal human, specific/hyperimmune human, antitoxins). Short duration (1-6 weeks). Useful for immediate exposure. E.g., diphtheria, tetanus, gas-gangrene, rabies, botulism. Examples of immunoglobulins: Hepatitis A (Ig), Hepatitis B (HBIG), Measles (Ig), Rabies (RIG), Tetanus (TIG).
    • Chemoprophylaxis: Using drugs for protection/prevention. Useful for close contacts of patients with cholera, diphtheria, meningococcal meningitis, plague, conjunctivitis.

Principles of Disease Prevention and Control

  • Focus on the chain of transmission: reservoir, routes, susceptible host. Often requires multiple control methods simultaneously.
  • Controlling the Reservoir:
    • Early Diagnosis: Rapid identification for treatment, epidemiological investigations, preventive control measures.
    • Notification: Reporting detected/suspected disease to local health authority (e.g., cholera, plague, yellow fever are notifiable under International Health Regulations).
    • Epidemiological Investigations: After outbreak, identify source and spread factors.
    • Isolation: Separation of infected persons during communicable period to prevent direct/indirect transmission. Effective for diphtheria, cholera, plague, chickenpox.
    • Treatment: Kills infectious agent in reservoir, reduces communicability, shortens illness, prevents secondary cases. E.g., early treatment of syphilis, gonorrhoea, tuberculosis, leprosy.
  • Blocking the Routes of Transfer: Changing environmental components.
    • Water treatment (typhoid, dysentery, hepatitis A, cholera, gastroenteritis).
    • Clean practices (hand washing, food cooking, refrigeration, disposal) for food-borne diseases.
    • Vector control for vector-borne diseases.
  • Protection of Susceptible Host:
    • Active Immunization: (As above) Strengthening natural defenses.
    • Passive Immunization: (As above).
    • Chemoprophylaxis: (As above).

Hospital-Acquired (Nosocomial) Infections

  • Definition: Infections developing in hospitalised patients, not present or incubating at admission, becoming evident during stay or after discharge.
  • Source: Any part of hospital ecosystem (people, objects, food, water, air).
  • Common Microorganisms:
    • Bacteria: (Not explicitly detailed, but implied as common causes, e.g., Staph. epidermidis, Strep. pyogens, Clostridium species in wound infections, Ps. aeruginosa in burns).
    • Viruses: Hepatitis B (most important, blood transfusion), viral diarrhoea, chickenpox, cytomegalovirus, herpes virus, influenza, enteroviruses, arenavirus.
    • Fungi: Yeasts (mainly Candida albicans), moulds (Aspergillus, Mucor).
    • Protozoa: (Entamoeba histolytica, Pneumocystis carinii, Toxoplasma gondii).
  • Common Types of Infections:
    • Wound infections: Post-operative (Staph. epidermidis, Strep. pyogens, Clostridium), non-surgical (injections, umbilical stumps, ulcers, burns - Ps. aeruginosa in burns).
    • Other common types: (Not explicitly detailed beyond wound infections, though mentioned as 4 types).
  • Prevention and Control:
    • Etiological diagnosis (smear, culture, identification, sensitivity).
    • In outbreak, identify and eliminate source (e.g., hospital personnel carriers, contaminated water/food, defective sterilisation).
    • Infection control team: Microbiologists, medical/nursing staff, hospital administrators. Formulate guidelines for admission, nursing, treatment of infectious patients, surveillance on sterilisation, education of patients/staff.
    • Avoid indiscriminate antibiotic use to prevent resistant pathogens.

Environment and Health

Introduction

  • Health status is an integration of internal human environment and external environment. Diseases due to disturbances in the balance between man and environment.
  • Environmental control is the first step in health programmes to eliminate detrimental factors.

Water Pollution

  • Sources:
    • Industrial pollutants: Diverse chemicals, metal salts, synthetic organic chemicals, pigments, dyes, sulphide, ammonia.
    • Agricultural pollutants: Pesticides, fertilizers.
    • Physical pollutants: Heat (thermal pollution), radioactive substances.
  • Hazards: Direct or through food/personal hygiene/recreation.
    • Biological hazards: Water-borne diseases (bacteria, viruses, protozoa, helminths).
    • Toxic hazards: Long-term toxic effects of chemical pollutants.

Purification of Water

  • Large Scale (Urban Water Supply Systems):
    1. Storage: Excludes further pollution, reduces bacteria, removes suspended impurities by sedimentation.
    2. Filtration: Slow sand filters (removes 99% bacteria), rapid sand filters.
    3. Disinfection: (Not explicitly detailed for large scale, but chlorination mentioned for wells).
  • Domestic Purification:
    • Boiling: Safest for small quantities, kills bacteria/spores/cysts/ova.
    • Chemical Disinfection: Bleaching powder, chlorine tablets.
    • Filters: Ceramic filters remove bacteria but not viruses; need regular cleaning/sterilisation.
  • Disinfection of Wells: Bleaching powder is most effective and economical.

Health and Air

  • Air is immediate environment, supplies oxygen, cools body, transmits stimuli for hearing/smelling. Carries disease-producing agents and microorganisms.

Noise

  • Health Hazard: Education of public through mass communication media needed to highlight importance of noise as a health hazard.

Solid Wastes Disposal and Control

  • Definition: Discarded waste from houses, street sweeping, commercial, industrial, agricultural operations (dust, ash, vegetables, paper, rags, glass, debris). Called refuse in cities, litter in countryside.
  • Hazards:
    • Fermentation of organic matter breeds flies.
    • Garbage attracts rats and pigs.
    • Pathogens carried by house flies and dust.
    • Risk of air and water pollution from combustion/fermentation.
    • Aesthetic nuisance.
  • Importance: Efficient collection, removal, and disposal reflect social development.

Medical Entomology: Arthropod-Borne Diseases and their Control

Arthropods of Medical Importance

  • Ways they cause disease: Vectors of infectious agents, envenomation (stings/bites), direct infestation/infection, allergic dermatitis.
  • Prevalence in India: Major health problem (Malaria 4-5 million cases/year, Filariasis, Guinea worm, Scabies, Dengue, Japanese encephalitis, Kyasanur forest disease, Trachoma).
  • Classification:
    1. Class Insecta: Mosquitoes, flies, human lice, fleas, winged bugs.
    2. Class Arachnida: Ticks, mites.
    3. Class Crustacea: Cyclops.
  • Transmission Processes:
    • Direct Contact: Arthropods directly transferred man-to-man (e.g., lice, mites, scabies).
    • Examples of diseases transmitted by specific arthropods:
      • Mosquitoes: Malaria, Filariasis, Dengue, Chikungunya, Encephalitis.
      • Soft ticks: Typhus fever, KFD, Tularemia.
      • Sand flies: Leishmaniasis, sandfly fever.
      • Lice: Epidemic louse fever, french fever, louse-borne relapsing fever.
      • Mites: Scrub Typhus fever, Rickettsial pox, Scabies.
      • Winged bugs: Chagas disease.
      • Fleas: Plague, Endemic typhus fever.
      • Cyclops: Guineaworm disease.

Arthropod Control Methods

  • Environmental Control: Long-lasting results. Elimination of breeding places, filling/drainage, planned water management, piped water supply, refuse disposal, house cleanliness, intensive health education.
  • Chemical Control: Insecticides (organochlorine, organophosphorus, carbamate). Resistance is an issue. Environmental pollution concern (DDT replaced by biodegradable methoxychlor).
  • Fly Papers: Sticky papers with resin/castor oil as adjuncts to fly control.
  • Protection against Flies: Screening houses, hospitals, restaurants, food/meat shops.
  • Health Education: Crucial for effective implementation of fly control and sanitary measures, motivating communities to adopt desired measures.
    • Methods can be modified for control of sand flies, tsetse fly, black flies, lice, fleas, bugs, ticks, and mites.

Rodents

  • Hazards: Health hazard, damage to buildings, grains, food, household commodities.
  • Classification: Domestic (black rat Rattus rattus, Norway rat R. norvegicus, house mouse Mus musculus) and wild.
    • Rattus rattus: Domestic, restricted movement, climber, infests roofs, burrows, infests ships, public health importance.
    • R. norvegicus: Semi-domestic, frequents sewers, drains, houses.
  • Diseases Transmitted by Rodents:
    • Bacterial: Plague, salmonellosis, leptospirosis, tularaemia.
    • Rickettsial: Murine typhus, scrub typhus, rickettsial pox, Q fever.
    • Viral: Lymphocytic choriomeningitis.
    • Parasitic: Hymenolepsis nana, H. diminuata.
    • Others: Rat bite fever, histoplasmosis, ringworm.
  • Mode of Transmission: Direct (rat bite), contamination of food/water (salmonellosis, leptospirosis), rat fleas (plague, typhus).
  • Control of Rodents:
    • Sanitary Measures: Environmental sanitation, denying food/water/shelter. Proper garbage storage/disposal, food storage, rat-proof construction, blocking burrows with concrete.
    • Chemical Measures: (Not detailed in provided text).

Other Animals (Zoonoses)

  • Definition: Diseases/infections of animals communicable to man (WHO lists >150).
  • Examples in India: Brucellosis, rabies, tuberculosis, leptospirosis, hydatid disease.
  • Table 4.3 (Selected Zoonoses): (Partial list from Table 4.3)
    • Bacterial: Brucellosis (Brucella melitensis), Tuberculosis (M. bovis), Leptospirosis (Leptospira interrogans), Plague (Yersinia pestis).
    • Viral: Rabies (Rabies virus), Viral encephalitis (Arboviruses).
    • Parasitic: Hydatidosis (E. granulosis), Taeniasis (T. saginata), Cysticercosis (T. solium), Leishmaniasis (L. donovani), Toxoplasmosis (T. gondii).

Nutrition and Health

Definition of Nutrition

  • A function of living plants and animals, taking in and assimilating material through chemical changes (metabolism) to build tissue and liberate energy.
  • Successive stages of metabolism: Digestion, absorption, assimilation, excretion (preceded by mastication and deglutition in man).

Diseases Induced by Deficiency of Proteins, Vitamins, and Minerals

  • Protein-Calorie Malnutrition (PCM): (Only general mention of deficiency diseases like malnutrition, anemia, scurvy, and goitre due to nutritional agents).
    • Prevention of PCM: Health education (pregnant/lactating mothers, breast feeding, family planning, nutrition/food requirements), specific protection of infants/children (timely immunization, protein/calorie rich foods like milk/eggs/flesh).
  • Obesity: Diet is the most important management factor. Preventive education about diet should start early. Motivation to reduce caloric intake is difficult for long-standing overeating patterns. Diets relying on special foods or unusual combinations are invalid and potentially harmful. Key points: decrease caloric intake.

Demography and Family Planning

Demography

  • Definition: Scientific study of human population.
  • Concerns: Changes in population size, composition, distribution in space.
  • Demographic Processes: Fertility, mortality, marriage, and social mobility.

Family Planning

  • WHO (1971) Definition: “A way of thinking and living that is adopted voluntarily, upon the basis of knowledge, attitudes and responsible decisions by individuals and couples, in order to promote the health and welfare of the family group and thus contribute effectively to the social development of a country”.
  • Scope of Family Planning (WHO):
    1. Proper spacing and limitation of births.
    2. Advice on sterility.
    3. Education for parenthood.
    4. Sex education.
    5. Screening for pathological conditions related to the reproductive system.
    6. Genetic counselling.
    7. Premarital consultation and examination.
    8. Carrying out pregnancy test.
    9. Marriage counselling.
    10. Preparation of couples for arrival of first child.
    11. Providing services to unmarried mothers.
    12. Teaching home economics and nutrition.
    13. Providing adoption services.
  • Family Planning and Health: Direct effect on mother, foetus, infant, and children’s health.
    • Mothers’ health: Decreased maternal mortality/morbidity, improved nutritional status, prevented pregnancy/abortion complications.
    • Foetal health: Decreased foetal mortality and abnormal development.
    • Infant and child health: Better infant health at birth, decreased vulnerability to diseases, decreased preschool mortality.

Contraceptive Methods

  • Scientifically tested and reliable methods available. Individual preferences vary, and different methods suit different life stages. Gynaecologist consultation often necessary.
  • Behavioural, natural, chemical, mechanical, hormonal methods: (Not detailed in provided text).

Population Problem of India

  • India crossed 906 million population mark before September 1994.

Fundamental Principles of Microbiology

Definition of Microbiology

  • Study of living organisms of microscopic size, including bacteria, fungi, algae, protozoa, and viruses. Concerns morphology, physiology, metabolism, reproduction, and classification.
  • Microbes are associated with human health and welfare, both beneficial (e.g., yogurt, cheese, penicillin production) and harmful (diseases, food deterioration).

Characteristics and Classification of Microbes

  • Size: (Bacteria 0.1-15 μm, Fungi/yeasts 2 μm-20 cm, Viruses/Bacteriophages 0.01-0.2 μm, Algae 1 μm-meters, Protozoa 5-250 μm).
  • Chemical Composition:
    • Cell Wall: Gram-positive bacteria (teichoic acid), Gram-negative bacteria (no teichoic acid). Fungi/algae have different constituents.
    • Nucleic Acid: Viruses distinguished by RNA or DNA.
  • Cultural Characteristics: Different microbes require specific nutrients and physical conditions (temperature, light, oxygen) for growth. Growth patterns vary in liquid (abundant/sparse, evenly distributed, sediment, pellicle) and solid media (colonies differ in size, shape, texture, consistency, color).
  • Metabolic Characteristics: Life processes vary in energy acquisition/use, chemical reactions, and regulation by enzymes.
  • Antigenic Characteristics: Special large chemical components (antigens) distinctive of certain microbes. Induce specific antibodies in host. Classified by position: Flagellar (H), Surface, Somatic.
  • Ecological Characteristics: Habitat is important (e.g., oral vs. intestinal microbial population).

Groups of Micro-organisms

  1. Bacteria.
  2. Fungi & yeasts.
  3. Viruses and Bacteriophages.
  4. Algae.
  5. Protozoa.

Isolation and Staining Techniques

  • Motility: Inoculate mixed culture on moist slope, motile organisms recovered from top of slope by swimming in liquid film.
  • Enrichment Media: Medium favors specific species growth and suppresses others. Useful for tracing epidemic sources (e.g., isolating typhoid organisms from sewage).

Organisms Producing Common Diseases

  • Gram Positive Cocci:
    • Staphylococcus: Grape-like aggregates, non-motile, non-sporing. S. aureus causes boils, abscesses, sties, osteomyelitis, food poisoning, impetigo, conjunctivitis.
    • Streptococcus: Ovoid rods, grow in chains. S. pyogenes causes scarlet fever, acute tonsillitis, puerperal sepsis, rheumatic fever, kidney inflammation.
    • Diplococcus: Similar to Streptococcus, grow in pairs. D. pneumoniae causes acute lobar pneumonia, meningitis, peritonitis, conjunctivitis.
  • Gram-Negative Cocci:
    • Neisseriae: In pairs, kidney bean shape, embedded in pus cells. N. gonorrhoeae causes venereal disease gonorrhoea. N. meningitidis causes cerebrospinal fever (meningococcal meningitis).
  • Gram Positive Rods:
    • Bacilli: Large rod, aerobic spore-forming, widespread. B. anthracis causes anthrax. B. cereus implicated in food poisoning.
  • Gram-Negative Rods: (Only Vibrio mentioned).
    • Vibrio: Comma-shaped, motile, non-sporing, aerobic. V. cholerae causes cholera.

Communicable Diseases

Respiratory Infections

Chicken Pox (Varicella)

  • Etiology: Caused by varicella-zoster virus.
  • Spread: Mostly by droplets from upper respiratory tract, discharge from ruptured skin lesions, or contact with herpes zoster.
  • Incidence: Highly infectious, mainly affects children under 10 years.
  • Severity: Adults may develop more severe illness; severe or fatal in immunocompromised (e.g., leukemia patients).
  • Incubation Period: 14 to 21 days.

Influenza

  • Etiology: Acute illness of respiratory tract, caused by myxoviruses.
  • Occurrence: Endemics, occasional pandemics.
  • Types: Influenza A (responsible for pandemics, at least four serologically distinct strains), Influenza B (smaller, less virulent outbreaks).
  • Immunity: (Not detailed).

Diphtheria

  • Etiology: Acute infectious disease caused by toxigenic gram-positive bacillus Corynebacterium diphtheriae.
  • Pathology: Infections in upper respiratory tract, sore throat. Spread by droplet infection from cases/carriers. Organisms localized at site, serious consequences from absorption of soluble exotoxin (damage heart muscle/nervous system).
  • Incubation Period: 2-4 days.
  • Isolation: Cases isolated until 6 daily nose and throat swabs are negative.
  • Prevention: Active immunization for children (DTP). Close contacts treated with erythromycin (more effective than penicillin in eradicating carriers). Contacts advised active immunization or toxoid booster.

Whooping Cough (Pertussis)

  • Etiology: Highly infectious disease caused by Bordetella pertussis. Spread by droplet infection.
  • Incidence: All ages, but ~90% cases in children under 5 years.
  • Incubation Periods: 7 to 14 days.
  • Prevention: Pertussis vaccine in multiple immunogen form (DTP) for active immunization of infants and children 6 weeks through 6 years.

Tuberculosis (TB)

  • Historical Role: Frightening disease (white plague, phthisis).
  • Pathophysiology: Diverse host-Mycobacterium relationship, from solitary granuloma to widely disseminated disease.
  • Treatment: Shifted from sanatorium to community hospital, private physician, general practitioners due to effective outpatient drug therapy.
  • Prophylactic INH Therapy: Preventive therapy with isoniazid reduces bacterial population, not truly prophylactic but treatment of infection. Reduces future morbidity in high-risk groups (60% reduction in proven disease over 7 years). Guidelines exist from American Thoracic Society and CDC.

Intestinal Infections

Hepatitis

  • Definition: Inflammation of liver, may lead to hepatic cell necrosis, caused by viruses, bacteria, chemicals.
  • Etiology: Hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis non-A non-B viruses (HNANB). HAV and HBV differ in incubation, mode of transmission, sequelae.
  • Prevention: Strict personal hygiene, clean/boiled drinking water, restricted fly access to food, vaccination (killed V. cholera suspension for limited protection). Control of water sources, population movement, public education during epidemic. Mass vaccination/treatment (tetracycline). Disinfection of infective discharges/soiled clothing, hand washing by medical attendants.

Food Poisoning (Gastroenteritis)

  • Causes (Table 8.8):
    • Infective Non-toxin mediated: Salmonella species, Campylobacter jejuni, Bacillus cereus, Viruses (e.g., Norwalk), Listeria monocytogens, Bacillus anthracis, Protozoa (Giardia, Cryptosporidium).
    • Toxin-mediated: Staphylococcus aureus, Clostridium perfringens, Clostridium botulinum.
  • Botulism: Unusual food poisoning from C. botulinum toxin (imperfectly treated tinned food, preserved fish). Clinical features: vomiting, slight paralysis of skeletal/ocular/pharyngeal/respiratory muscles. High mortality.
  • Prevention: Improve personal hygiene (especially food handlers), hand washing (after lavatory, before meals). Proper thawing of frozen food (especially poultry).

Amoebiasis

  • Etiology: Caused by Entamoeba histolytica, a potentially pathogenic intestinal amoeba.
  • Epidemiology: Simple life cycle, exists in cysts and trophozoites. Cysts released from bowel perpetuate infection. Asymptomatic infected host excretes cysts, transmits infection.
  • Prevention: Check contamination of water, food, vegetables, fruits with human faeces. Filtered/boiled drinking water (chlorination not effective against cysts). Treat vegetables/fruits with iodine (200 ppm) or acetic acid (5-10%), wash with detergents. Sanitary disposal of human excreta. Periodic examination of food handlers, education on personal hygiene. Requires effective health education.

Arthropod-Borne Infections

Plague

  • Etiology: Yersinia pestis (small gram-negative bacillus).
  • Spread: Between rodents by fleas. Infected domestic rats’ fleas bite man. Later stages of human plague: inter-human spread by droplets from expectorated Y. pestis.
  • Prevention: Control flea biting (powder with Dieldrin/Aldrin on floors, into rat holes). Avoid handling wild animals in endemic areas. Patient isolation, attendants wear gowns/masks/gloves. Contacts protected by tetracycline (2g daily for a week).
  • Vaccination: Plague vaccine (two doses 0.5 and 1.0 ml subcutaneously 7-14 days apart) is valuable preventive measure, given a week before anticipated outbreak. Booster doses recommended 6-monthly for ongoing risk.

Filariasis

  • Prevention: Mass treatment of entire population in endemic areas with diethylcarbamazine (adults 100 mg tid for 7 days, children 50 mg tid for 7 days). Combine with vector control by insecticides. Early chemotherapy prevents later elephantiasis.

Surface Infections

Rabies

  • Etiology: (Virus).
  • Prevention: (Immunization and Rabies Immune Globulin [RIG] as discussed in Immunization section).

Trachoma

  • Prevention: Improve personal/family cleanliness, proper eye care for newborns/children. Examine/treat family contacts. General population surveys (schools/offices) to find asymptomatic infections. Trachoma clinics in endemic areas. Mass campaigns with topical tetracycline and socioeconomic improvement reduce incidence. School children screening and education.

Tetanus

  • Etiology: Infection with Clostridium tetani.
  • Prevention: (Tetanus Immune Globulin [TIG] as discussed in Immunization section).

Leprosy

  • Prevention: Mass prophylaxis impossible, but treatment/follow-up of identified cases reduces deformity and lowers incidence. Improvement of socioeconomic conditions and health education lead to disease disappearance.

Scabies and Pediculosis

  • Scabies: Produced by mite Sarcoptes scabei. Female mite burrows into stratum corneum, lays eggs. Burrows appear as irregular grayish-black lines, ‘5’ shaped, papule at one end. Common sites: interdigital spaces, elbows, wrist, feet, buttocks, axillary folds, penis, nipples in females.
  • Pediculosis: (Infestation with lice).

Sexually Transmitted Diseases (STDs)

  • Control: Reducing silent reservoir of infection, preventing further disease. Requires team effort: accurate diagnosis, specific curative treatment, contact tracing, post-treatment surveillance, education, social/medical awareness.

Syphilis

  • Etiology: Treponema pallidus (spirochete). Can invade any tissue/organ causing acute, chronic, or contagious syphilis.
  • Infection: Usually through sexual activity; fetus can be infected during birth (congenital syphilis).
  • Prevention: Pharmacists play active role: disseminate accurate information, propagate prophylactic measures. Condom is effective mechanical barrier. Advise on compliance, follow-up. Washing genitals, urinating after intercourse can reduce infection. Careful douching may also help.

Gonorrhoea

  • Etiology: Neisseria gonorrhoeae. Second most common notifiable STD in US.
  • Infections: Localized, uncomplicated, or complicated genital infections (urethritis, cervicitis, endometritis, PID in women; urethritis, epididymitis in men), pharyngitis, anorectal infections, disseminated infection (septic arthritis, meningitis).
  • Symptoms: Women with genital tract infection and patients with pharyngeal infection often asymptomatic. Men with urethritis often display dysuria and urethral discharge.
  • Co-infection: Often co-infected with Chlamydia trachomatis, syphilis, Trichomonas vaginalis. Diagnosis/treatment of all possible STDs in patient and partners are important.
  • Prevention: Pharmacists can disseminate information, propagate prophylactic measures (condom), advise on compliance/follow-up, hygiene.

AIDS (Human Immunodeficiency Virus - HIV)

  • Causative Agent: HIV (enveloped, positively stranded RNA virus, Retroviridae family, Lentivirus genus).
  • Patient Characteristics: Many with serologic evidence of HIV infection may not manifest symptoms, neurologic disease, or overt AIDS (defined by opportunistic infection/malignancy).
  • Risk Populations: Homosexual males, intravenous drug abusers, hemophiliacs, sexual partners of these groups.
  • Transmission: Strong evidence of transmission by sexual contact or contact with contaminated blood/blood products (including heterosexuals). Mother-to-child transmission (in utero, labor/delivery, breastfeeding).
  • Detection: Blood tests for antibodies to HIV are major achievement.
  • Control:
    • Prevention of Transmission: Modification of sexual practices (promiscuity, anal intercourse), screening of donated blood/blood products for HIV antibody, counselling antibody-positive persons.
    • Precautions: Avoid indiscriminate sex, shared razors/toothbrushes, sharing needles/syringes by IV drug users. HIV-positive women should avoid pregnancy.
    • Education: Educational material/guidelines freely distributed. Mass media (newspaper, radio, TV) actively involved in educating people about AIDS (nature, transmission, prevention).
    • Blood Donors: High-risk persons refrained from donating blood/organs (kidneys, eyes, sperm).
    • Injections: Pre-sterilised and disposable syringes should be used.

Meningitis

  • Definition: Infectious diseases medical emergency requiring prompt diagnosis and treatment.
  • Etiology: Caused by bacteria, viruses, fungi, or mycobacteria, producing acute or chronic meningitis.
  • Diagnosis:
    • Lumbar Puncture: Performed to obtain CSF for laboratory analysis. Opening pressure measured (normal 50-195 mm H2O in adults), often elevated in meningitis.
    • CSF Analysis: Placed in 3-4 sterile tubes for microbiologic (Gram stain, fungal/AFB stains, culture, antigen detection) and chemical studies (appearance, glucose, protein), and WBC count with differential.
    • Head CT: Performed prior to lumbar puncture if papilledema, altered consciousness, new onset seizures, or focal neurological findings to exclude space-occupying lesion (risk of brain herniation).

Non-Communicable Diseases

Cancers

  • Definition: Wide variety of malignant diseases. Characterised by:
    1. Abnormal growth of cells.
    2. Ability to invade adjacent tissues and distant organs (metastases).
    3. Eventual death if tumor progresses beyond treatable stage.
  • The Cancer Problem:
    • Responsible for ~9% of total deaths worldwide. Second leading cause of death in developed countries (19% mortality), fourth in developing countries (6% mortality).
    • Kills 800,000 Indians annually. Incidence rising in India with life expectancy and control of communicable diseases.
    • Incidence in India ~70 per 100,000 population (vs. 289 per 100,000 in developed countries).
    • Common Organ Sites in India: Uterine cervix in women, oropharynx in both sexes. Other prominent types in females: breast, ovary, oesophagus, stomach, rectum. In males: prostate, lung, oesophagus, stomach, large intestine, rectum.
  • Etiology (Multifactorial): 90% of all cancer deaths attributed to potentially avoidable factors: tobacco, alcohol, diet, reproductive/sexual behaviour, occupation, pollution, geographical features.
    • Tobacco: Major environmental cause of cancers (lung, larynx, mouth, pharynx, oesophagus, bladder, pancreas, kidney). Responsible for >1 million premature deaths annually worldwide. Public health campaigns prove successful but need to continue, especially for youth.
  • Prevention of Cancer: Aims for significant reduction in new cases, increased cure rate, reduced invalidism. Estimated at least one-third of all cancers are preventable.
    • Primary Prevention: Control of important causative factors.
      • Control of tobacco and alcoholic beverages.
      • Food, Drugs & Cosmetics: Regular checks for carcinogenic materials.
      • Treatment of precancerous lesions (e.g., cervical tears, warts, chronic gastritis, chronic cervicitis).
      • Cancer education: Early detection and prevention (e.g., breast self-examination). Voluntary organisations and cancer hospitals remind public of early warning signs.
      • Early Warning Signs: Lump/hard area in breast, change in wart/mole, persistent change in digestive/bowel habits, persistent cough/hoarseness, excessive blood loss at monthly period/bleeding outside dates, blood loss from any natural orifice, swelling/sore that doesn’t heal, unexplained weight loss.
    • Secondary Prevention: (Not explicitly detailed as a separate heading but implied by early detection and treatment).

Blindness

  • WHO Definition: Visual acuity <3/60 (Snellen) or equivalent in better eye, or field of vision 20° or less. Inability to count fingers at 3 meters in daylight.
  • Causes:
    • Infectious Diseases: Gonorrhoea, syphilis (untreated in pregnant women), trachoma, leprosy, tuberculosis, meningitis, measles, diphtheria, scarlet fever.
    • Parasitic: Onchocerciasis (roundworm invasion of eyes).
    • Non-infective Systemic Diseases: (Mentioned, but not detailed).
  • Prevalence in India: 9 million blind people (85% curable), another 45 million visually impaired. Huge economic and social burden. Prevalence 1.5% for country.
  • Eye Health Care: Comprehensive concept comprises:
    1. Primary eye care: Added to primary health care. Promotion/protection of eye health, on-the-spot treatment for common diseases.
    2. Epidemiological approach: Studies at population level, measuring incidence/prevalence/risk factors.
    3. Team approach: Auxiliary health personnel (village health guides, ophthalmic assistants, medical social workers, voluntary agencies) due to insufficient eye specialists.
    4. National programmes: National Programme for Control of Blindness (Ministry of Health and Family Welfare, Govt. of India, 1976). Goal: reduce blindness to 0.3% by 2000 AD.
  • Prevention of Blindness:
    • Methods: Improving nutrition, treating infectious diseases, controlling infection-causing organisms, improving safety conditions (workplaces, roads, home).
    • Initial assessment of prevalence: Essential for setting priorities and developing intervention programmes.
    • Primary eye care: (As above) for acute conjunctivitis, trachoma, xerophthalmia, ophthalmia neonatorum. Provided by trained primary health workers, social workers, guides with essential drugs (sulphacetamide, tetracycline, Vitamin A). Refer serious cases. Promote personal hygiene, sanitation, diet, safety.
    • Secondary care: Management of common blinding conditions: cataract, glaucoma, ocular trauma. Provided at PHCs and district hospitals by qualified eye specialists. Mobile eye clinics and eye camps for cataract surgery.
    • Tertiary care: Sophisticated eye care (retinal detachment surgery, corneal grafting). Established in medical colleges, leading medical institutions. Eye Banks for corneal grafting. National Institute for the Blind (Dehradun).
    • Specific Eye Care Programmes:
      • Trachoma control: Mass campaigns with topical tetracycline, socio-economic improvement reduced incidence.
      • Eye Care at school level: Screening/treatment for refractive errors, squint, amblyopia, trachoma. Teaching good posture, proper lighting, avoidance of glare, adequate reading distance/angle. Publishers advised to use suitable letter types.

Diabetes

  • (Discussed in relation to medication adherence, and in detail under “Clinical Laboratory Data Interpretation” for screening, diagnosis, and management.)

Hypertension

  • (Discussed in relation to medication adherence, and in detail under “Clinical Laboratory Data Interpretation” for guidelines and management.)

Epilepsy

  • Drug Therapy: Almost exclusively pharmacotherapy. Patient education on medications, and TDM are essential.
  • Objective: Reduce seizure frequency and severity without undue adverse effects (sedation, impaired activity). Complete seizure control in 70-80% of patients by removing underlying cause, increasing seizure threshold, or preventing synchronous spread of impulses with optimal anticonvulsant therapy.
  • Practical Considerations: Consider factors known to reduce seizures (fever, edema), optimal anticonvulsant therapy.

First Aid

Shock

  • Definition: (Not explicitly defined in the provided text beyond being a severe medical state).
  • Classification of Different Types of Shock and their Etiological Factors (Table 10.1):
    1. Hypovolemic shock:
      • Loss of blood (hemorrhage).
      • Loss of plasma (burns).
      • Loss of fluid (diarrhoea, vomiting, diabetes mellitus, diabetes insipidus, overuse of diuretics).
    2. Cardiogenic shock:
      • Myocardial infarction.
      • Heart failure with low cardiac output.
      • Arrhythmias.
  • Note: One type of shock may take on characteristics and sequelae of another.

Disinfection

Definitions

  • Disinfection: Process that removes infectious potential by destroying microorganisms but not ordinarily bacterial spores. Usually refers to chemical agents on inanimate objects.
  • Sterilization: Process by which all viable forms of microorganisms, including bacterial spores, are destroyed.
  • Antiseptic: Substance that arrests or prevents microorganism growth by inhibiting activity without necessarily destroying them. Suitable for living tissues. A disinfectant can act as an antiseptic in low concentrations.

Types of Disinfections

  • Concurrent Disinfection: Microorganisms destroyed as soon as released from body, stopping further disease spread. Disinfection of urine, faeces, vomitus, contaminated linen, clothes, dressings, gloves, aprons, hands etc. throughout illness.
  • Terminal Disinfection: Disinfective measures after patient removal (death, transfer, ceased being source of infection). Scarcely practised now, as terminal cleaning, airing, sunlight exposure are considered adequate.
  • Precurrent or Prophylactic Disinfection: Achieved by disinfection of water (chlorine), pasteurization of milk, hand washing.

Disinfectants (Agents)

  • Physical Agents:
    1. Sunlight: Appreciable bactericidal activity (UV rays lethal to bacteria, some viruses). Disinfects articles (linen, bedding, furniture) by several hours’ exposure.
    2. Burning.
    3. Hot air.
    4. Boiling.
    5. Autoclaving.
    6. Radiation.
  • Chemical Agents:
    1. Alcohols.
    2. Phenols and related compounds.
    3. Surface active compounds.
    4. Halogens.
    5. Dyes.
    6. Gases.

Disinfection Procedures

  • Dead bodies: Preserved in formalin for dissection. Bodies of patients who died of serious infectious diseases cleaned with disinfectant, stored in mortuary until cremation. Mortuary kept clean and disinfected.

Arthropod Control

This section is covered under “Environment and Health” above. Please refer to that section for details on Arthropods of Medical Importance, Transmission, and Methods of Control.