39.1    INTRODUCTION

In the previous lesson you read about the diseases due to nutritional deficiencies. Here you will read about some other categories of diseases.

39.2    OBJECTIVES

After completing this lesson you will be able to:

  • define the term disease.
  • categorise the diseases.
  • define some common terms like parasite, pathogen, infestation, vector, carrier, host, reservoir, inoculation, vaccination, interferons, epidemic, endemic, pandemic.
  • list the communicable diseases like chicken pox, measles, cholera, tuberculosis, malaria, diphtheria, dysentery, poliomyletis, amoebiasis, filariasis, rabies, hepatitis, typhoid.
  • explain the cause, symptoms and prevention of the diseases mentioned above.
  • mention that a disease can be transmitted during pregnancy like German measles and its prevention.
  • list the non-communicable diseases like coronary disease, hypertension, diabetes, allergy, cancer.
  • mention the various factors responsible for the non-communicable diseases and their cure.
    •

    39.3     TYPES OF DISEASES

     

    What is a disease?

    Any condition which interferes with the normal functioning of the body is called a disease.

    The diseases may be of two broad categories:

     

    A.   Congenital disease: The disease which is present from birth (e.g. hole in the heart ininfants)

    B.   Acquired disease: The disease which may occur after birth during one's lifetime.

     

    Acquired diseases may generally be classified into:-

     

    i.        Infectious diseases: The diseases which can be transmitted from person to person e.g. measles.

    ii.        Degenerative diseases : The diseases caused by the malfunction of some vital organs of the body e.g. heart.

    iii.       Deficiency diseases: These are caused due to nutritional deficiency of mineral or vitamins e.g. anaemia; (Fe), Ben beri (vitamin B). You have read about such diseases in the previous chapter.

    iv.      Cancer: This is abnormal, uncontrolled and unwanted growth of cells like breast cancer.

     

    Acquired diseases are studied under two categories:

    i.        Communicable diseases: The diseases which can be transmsitted from one infected person to another healthy person.

    ii.         Non-communicable diseases: These diseases do no spread from one affected   person to another healthy person.

    39.4     SOME IMPORTANT TERMS TO UNDERSTAND AND REMEMBER

    Pathogen: A living organism which produces a disease.
    Parasite: An organism which gets food and shelter from host.
    Host: The living body on or inside which me disease - producing organism takes shelter.
    Infestation: A large number of parasitic organisms present on the surface of body of the host or in its clothings.
    Vector: It is an organism which harbours a pathogen and may pass it on to another person to cause a disease (Mosquito harbours malarial parasite and transmits it to humans.
    Carrier: It is an organism which itself does not harbour the pathogen but physically transmits it to another person (Housefly is the carrier of cholera germs).
    Reservoir: An organism which harbours pathogen in large numbers and does not suffer itself.
    Epidemic: Spreading of a disease among many people in the same place for some time e.g. plague.
    Endemic: A disease which is regularly found among a particular group of people e.g. goitre.
    Pendemic: A disease which is found all over the world e.g. AIDS.
    Interferon: Type of proteins produced by infected cells of the body when attacked by a virus, which act of prevent the virus development further.
    Inoculation: Introduction of antigenic material inside the body to prevent a disease.
    Vaccination : Injection of a weak strain of a specific bacterium (Vaccine) in order to Seeure immunity against the Corresponding disease. It is also called immunisation.
    Incubation period : The period between entry of pathogen inside a healthy body and appearance of the symptoms of the disease.
    Symptoms: The expressions which appear on the body to identify a disease.

    39.5    COMMUNICABLE DISEASES (INFECTIOUS DISEASES)

     

    The diseases which spread from one person to another through contaminated food, water or contact or through insecticides, animals etc. are called the communicable diseases. These are caused by different causative agents (Pathogens).

     

    Some common communicable diseases of humans that are caused by viruses, bacteria, protozoans, and worms are described below :-

     

    A.     Diseases Caused by Viruses

    1.    Chicken pox

     

    Pathogen : Chicken pox virus (varicells)

    Mode of Transmission : By contact or through scabbs

    Incubation period : 12-20 days

     

    Symptoms

    i.         Fever, headache and loss of appetite

    ii.        Followed by dark red-coloured rash on the back and chest which spread on the whole body.

    iii.       Later, rashes change into vesicles.

    iv.       After few days these vesicles start drying up and scabbs (crusts are formed.)

    v.        These scabs start falling (infective stage)

     

    Prevention and Cure

    There is no vaccine against chicken pox as yet. But precautions must be taken as follows:-

    i.        The patient should be kept in isolation.

    ii.       Clothings, utencils etc used by the patient should be sterilised.

    iii.      Fallen scabs should be collected and burnt.

     

    One attack of chicken pox gives life long immunity to the recovered person from this disease.

     

    2    Measles

     

    Pathogen: Virus (Rubeola)

    Mode of Transmission: By air

    Incubation period: 3-5 days

     

    Symptoms

    i.        Common cold

    ii.       Appearance of small white patches in mouth and throat.

    iii.      Red rashes appear on the body.

     

    Prevention and Cure

    i.        Antibiotics check only the secondary infection which can easily occur.

    ii.        The patient should be kept in isolation.

    iii.       Cleanliness should be maintained.

     

    3.    Poliomylitis

     

    Pathogen : Polio Virus

    Mode of transmisssion: Virus enters inside the body through food or water.

    Incubation period: 7-14 days

     

    Symptoms

    i.         The virus multiplies in intestinal cells and then reaches the brain through blood.

    ii.        It damages brain and nerves and causes infantile paralysis.

    iii.       Stiffaess of neck, fever, loss of head support.

     

    Prevention and Cure

    Polio vaccine drops are given to children after certain intervals.

    Pulse programme is organised to give polio vaccine to children after a certain period of

    time.

     

    Rabies (also called hydrophobia)

     

    Pathogen: Rabies Virus

     

    Mode of Transmission: Bite by a rabid dog.

    Incubation period: 10 days to 1 -3 months depending upon the distance of bite from Central Nervous System (CNS)

     

    Symptoms

    i.        Severe headache and high fever.

    ii.       Painful contraction of muscles of throat and chest.

    iii.      Choking and fear from water leading to death.

     

    Prevention and Cure

    i.        Compulsory immunisation of dogs.

    ii.       Killing of rabid animals.

    iii.      Anti-rabies injections or oral doses are given to the person bitten by a rabid animal.

     

    5    Hepatitis

     

    Pathogen: Hepatitis B Virus.

    Mode of Transmission: Mainly through contaminated water

    Incubation Period: Generally-160 days.

     

    Symptoms

    i.        Body ache.

    ii.       Loss of appetite and nausea.

    iii.      Eyes and skin become yellowish, urine deep yellow in colour (due to bile pigments).

    iv.      Enlarged liver.

     

    Prevention and Cure

    i.        Hepatitis B vaccine is now available in India.

    ii.        Proper hygiene is to be observed.

    iii.       Avoid taking fat rich substances.

     

    B    Diseases caused by Bacteria

     

    1.    Tuberculosis

     

    Pathogen : A bacterium (Mycobacterium tuberculosis)

    Mode of Transmission: airborne - discharged through sputum, cough, sneeze, etc. of the

    infected person.

    Incubation period: 2-10 weeks during which the bacteria produce a toxin tuberculin.

     

    Symptoms

    i.        Persistent fever and coughing.

    ii.       Chest pain and blood comes out with the sputum.

    iii.      General weakness is felt.

     

    Prevention and Cure

    i.        Isolation of patient.

    ii.        CG vaccination is given to children as a preventive measure.

    iii.        Living rooms should be airy, neat and with clean surroundings.

    iv.        Antibiotics be administered as treatment.

     

    2.    Typhoid

     

    Pathogen: A Bacillus rod-shaped bacterium {Salmonella typhi)

    Mode of transmission; Through contaminated food and water.

    Incubation period: About 1-3 weeks.

     

    Symptoms

    i.        Continuous fever, headache, slow pulse.

    ii.       Reddish rashes appear on the stomach.

    iii.      In extreme cases, ulcers may rupture resulting in death of the patient.

     

    Prevention and Cure

    i.         Anti-typhoid inoculation should be given.

    ii.        Avoid taking exposed food and drinks.

    iii.       Proper sanitation and cleanliness should be maintained.

    iv.       Proper disposal of excreta of patient.

    v.        Antibiotics should be administered.

     

    3.    Cholera

     

    It often breaks among crowded and poorly satiated populations.

     

    Pathogen: Comma shaped bacterium (Vibrio cholerae)

    Mode of transmission: Contaminated food and water.

    House - fly is the carrier.

    Incubation period; 6 hours to 2-3 days.

     

    Symptoms

    i.        Acute diarrhea.

    ii.       Muscular cramps.

    iii.      Watery stool.

    iv.      Loss of minerals through urine.

    v.       Dehydration leads to death.

     

    Prevention and cure

    i.        Cholera vaccination be given.

    ii.       Electrolytes (NaK, sugar, etc.) dissolved in water should be given to the patient to check dehydration (In market it is available as ORS, oral rehydration solution).

    iii.      Proper washing and cooking of food.

    iv.      Proper disposal of vomit and human excreta.

    v.       Flies should not be allowed to sit on eatables and utensils.

     

    4.    Diphtheria

    This disease generally occurs in a children from 1 -5 years.

     

    Pathogen: Rod-shaped bacterium (Comybacterium diphthered)

    Mode of Transmission: Through air (droplet infection). Incubation period: 2-4 days.

     

    Symptoms

    i.        Slight fever.

    ii.       Sore throat and general indisposition.

    iii.      Oozing semisolid material in the throat which develops into a tough membrane.

    iv.      The membrane may cause choking of air passage, resulting into death.

     

    Prevention and Cure

    i.        Immediate medical attention be given.

    ii.       Babies be given DPT Vaccine.

    iii.      Sputum oral and nasal discharges of the infected child should be disposed off.

    iv.      Antibiotic may be given.

    v.        Isolation of the infected child.

     

    5.    Leprosy

     

    Pathogen : A bacterium (Mycobacterium leprae}

    Mode of transmission : Prolonged intimate contact with the infected person. Nasal secretions are the most likely infectious material for family contacts.

    Incubation period             1-5 years.

     

    Symptoms

    i.        Affects skin.

    ii.       Formation of nodules and ulcer.

    iii.      Scabs deformities of fingers and toes.

    iv.      Infected areas lose sensation.

     

    Prevention and Cure

    i.         The children should be kept away from parents suffering from leprosy.

    ii.         Some medicine may arrrest the disease to spread.

     

    6.    Dysentery (Bacillary): (Diarrhoeal disease)

     

    Pathogen : Many types of bacteria (E. Coli, Shigella species)

    Mode of transmission : Contaminated food and drink.

    Incubation period : Few hours to one day.

     

    Symptoms

    i.        Frequent passing of stool and vomitting.

    ii.       Stool may contain mucus and blood.

    iii.      Muscular pain in the stomach.

    iv.      Dehydration in acute cases, resulting in death,

     

    Prevention and cure

    i.        Cut and food exposed to flies, should not be taken.

    ii.       Vegetables and fruits should be washed properly.

    iii.      Taking electrolytes to overcome dehydration.

     

    SUGGESTED IMMUNISATION SCHEDULE

     

    Vaccine Primary Re-vaccination

    Primary

    Re-vaccination

    BCG

    (Against tuberculosis)

    After 1 month

     

     

    Meningitis (A&C)

    6 months-2 years

    yearly

    DPT Triple Antigen

    (Against Diptheria,

    Tetanus, Whooping cough)

    Start after 2 Months;

    3 such injections at 4-8 weeks interval

    1, 1½ years & 5 years;

    DT at 10 years

    Oral polio drops

    Start at 1 month

    5 does at 4-8 weeks interval

    Once every year till 10 years

    Typhoid

    Start at 2 years (Typhum VI)

    Every 3 years

    Hep-B

    1st dose at elected date, 2nd dose 1 month later 3rd dose 6 months after 1st dose

    Booster after 5 years

    Measles/MMR

    After 9 months

    15 months

     

    D.     Diseases caused by protozoans

     

    1.     Malaria

    Pathogen: Malarial parasite (Different species ofPlasmodium)

    Mode of transmission: By bite of female Anopheles.

    Incubation period: Approximately 12 days.

     

    Symptoms

    i.        Headache, nausea and muscular pain.

    ii.       Chilling and shivering.

    iii.      Followed by fever which becomes normal after some time.

    iv.      The above steps recur after certain period of time.

    v.       The patient becomes weak and anaemic.

    vi.       If not treated properly secondary complications may lead to death.

     

    Prevention and cure

    i.        Fitting of double door and windows (with "Jali" i.e. wire mesh)in the house to prevent entry of mosquitoes.

    ii.       Use of mosquito net and mosquito repellants.

    iii.      No water should be allowed to collect in ditches or other open spaces to prevent mosquito breeding.

    iv.       Sprinkling of kerosene oil in ditches or other open spaces where water gets collected.

    v.        Antimalarial drugs to be taken.

     

    2.    Amoebiasis (Amoebic dysentery)

    Pathogen : Entamoeba histolytica.

    Mode of transmission: Contaminated food and water.

     

    Symptoms

    i.        Formation of ulcers in intestine.

    ii.       Feeling of abdominal pain and nausea.

    iii.      Acute diarrhoea and mucus in stool.

     

    Prevention and cure

    i.        Proper sanitation should be maintained.

    ii.       Vegetables and fruits must be properly washed.

    iii.      Antibiotics may be given to the patients.

     

    D.     Diseases caused by worms (helminths)

     

    1.    Filariasis

     

    Pathogen: Filarial worm (Wucherena bcnwpfti)

    Mode of transmission : Bites of mosquitoes -Aedes and Culex.

     

    Symptoms

    i.        Fever

    ii.        Collection ofendothellial cells and metabolites in the wall of lymph vessels.

    iii.       Swelling takes place in certain parts of the body like legs, breasts, scrotum etc.

    iv.       Swelling of legs; which appear as legs of elephant, so it is also called eVepVvariaasvs. (Fig. 39.1)

     

    Fig. 39.1 Elephantiasis

     

    Prevention and Cure

    i.        Double doors and windows in the house to check the atry of mosquitoes.

    ii.        The water collected in tanks or otherarticles should be properly covered.

    iii.       Sprinkling of kerosene in ditches, etc

    iv.       Dings may be administered.

    39.6     DISEASE DURING PREGNANCY

     

    German measles

    It is a mild type of disease, which is passed on to the developing foetus during pregnancy from tt)e mother.

     

    Pathogen: Rubella.

    Mode of Transmission; Through air (air borne) to mother and then to foetus.

    Incubation period: Generally 1 -20 weeks of pregnancy.

     

    Symptoms

    Appearance of rashes on the mother's body.

     

    Prevention and cure

    i.         Get vaccinated after blood test before getting pregnant.

    ii.        Avoid contact with children who may have it.

    iii.       Take medicine as prescribed.

    39.7     NON-COMMUNICABLE DISEASES

     

    1.    Diabetes mellitus

    The disease can be diagnosed by blood test or urine test.

     

    Causes

     

    i.         Less secretion of insulin hormone from the pancreas.

    ii.        Obesity (Very fat).

    iii.      Mental shocks.

    iv.     Through heredity.

     

    Symptoms

     

    i.         More glucose in blood.

    ii.        Excessive and frequent passing of urine.

    iii.      Feeling more of thirst and hunger.

    iv.     Reduced healing capacity of injury.

    v.       General weakness of the body.

    vi.     In extreme cases diabetic coma can take place.

     

    Prevention and cure

    i.         Control the excessive weight of the body.

    ii.        A regulated and controlled diet is to be taken.

    iii.       The food should not contain sugar and much carbohydrates.

    iv.       Injection of insulin to be taken before meals, if required (Only on doctor's prescription).

     

    2.    Cardio Vascular

     

    Common Causes

     

    i.         Deposition of cholesterol (a kind of fat) in the walls of coronary arteries which restricts the flow of blood to the heart muscles. This commonly leads to heart attack.

    ii.        Due to reduced blood supply of oxygen available to the muscles the heart's efficiency is affected.

    iii.       Due to stress and strain.

    iv.       Obesity (Over weight).

     

    a)     Hypertension: (Properly but wrongly called high blood pressure)

     

    Symptoms

    i.         Persistent high blood pressure (B.P.)

    ii.        It may damage the arteries of kidney.

    iii.      In extreme cases the arteries may burst or blindness may be caused.

    iv.      It may also cause paralysis.

     

    Prevention and Cure

    i.         Do not build up mental tension.

    ii.        Low fat diet should be taken.

    iii.       Weight of the body must be kept under control.

    iv.       Good eating habits be developed.

    v.        Medicines may be taken.

     

    (b)    Coronary heart disease

     

    Symptoms

    i.         Severe pain in the chest is felt.

    ii.        Intense nausea and vomiting.

    iii.       Lot of sweating takes place.

    iv.       Blood clot may be formed within the blood vessels.

    v.        Gasping for breath.

     

    Prevention and Cure

    i.         A diet low in saturated fats may control the formation of cholesterol.

    ii.        Sound eating habits be developed.

    iii.       Over weight should be checked.

    iv.       Avoid smoking, alcoholic drinks and drugs.

    v.        Take treatment under a qualified doctor.

    vi.       Electro cardio gram (ECG) can diagnose the disease.

    vii.     By-pass surgery is performed in extreme cases.

     

    3    Cancer

    It is the uncontrolled and Unwanted growth of cells.

     

    Cause

    i.          No definite cause has been arrived at so far. However, it is found that body has proto-oncogones. These are activated by some substances or stimulus, which convert these into active cancer -causing oncogenes.

    ii.         Heavy snioking and alcoholism.

    iii.        Chewing of tobacco.

    iv.        Consistent irritation of skin or repeated injury at the same point.

     

    Cancer is a kind of tumorous growth. However, tumours can be classified into two categories :

     

    a)    Benign Tumour

    It remains confined to the place of origin and does not spread to other body parts. It is relatively harmless.

     

    b)    Malignant Tumour

    It spreads to other parts of the body and growth is rapid. This is serious and may cause death of the patient.

     

    Symptoms

    i.         Persistent lump or thickening in tissues, specially in tongue, breast and uterus.

    ii.        Any irregular bleeding or blood-tinged discharge from any body opening.

    iii.       Any sore that does not heal quickly.

    iv.       Change in the form of mole or wart.

    v.        Persistent hoarseness in voice, cough or difficulty in swallowing.

     

    Prevention and cure

    i.         Cancer check up be done once a year.

    ii.        Treatment should be taken under medical advice.

    iii.       Avoid smoking, alcohols and chewing of tobacco.

    iv.       Observe regularity in life to keep body healthy.

     

    4.    Allergy

    i.         Includes a group of non-infectious diseases.

    ii.        No definite cause is known.

    iii.     It is believed that they occur due to hypersensitiviness of certain individuals to foreign matter which may enter inside the body (allergens).

    iv.     Symptoms may be sneezing, gasping, running of eyes, irritation of throat or trachea,etc.

    v.      Allergens may be pollen grains, feathers, some animals/insects, drugs, medicines, odour etc.

    39.8 WHAT YOU HAVE LEARNT

     

    Diseases are broadly classifed into two categories

     

    Acquired (Occur after birth) and congenital (present from birth)

     

    39.10    TERMINAL QUESTIONS

     

    1.    Name the two categories of acquired diseases.

    2.    Explain the terms i) parasitism ii) Reservoir.

    3.    Give two symptoms of coronary diseases and typhoid.

    4.    Mention the precautions to check malaria.

    5.    Name the pathogen that causes Diptheria and cholera.

    6.    Name the carrier of cholera germ.

    7.    Mention the four types of acquired diseases.