CHAPTER 2: DISEASES – SCIENCE STANDARD FOUR NOTES

CHAPTER 2: DISEASES – SCIENCE STANDARD FOUR NOTES

DESCRIBE TYPES OF COMMON HUMAN DISEASES

DISEASES

A disorder in the normal functioning of a part or the whole body of an organism

There are two main groups of diseases:

1. Communicable
2. Non-communicable

Communicable diseases are diseases that can spread from one person to another through different means.

Non-communicable diseases are diseases that cannot spread from one person to another.

Spread of communicable diseases

• Communicable diseases are caused by pathogens.
• Pathogens are disease causing organism or germs.
• These include;
• virus,
• bacteria,
• fungi and,
• protozoa

CAUSES OF COMMUNICABLE DISEASES

Communicable diseases spread from sick to healthy people through different ways such as;

a) Contaminated food – Food contaminated by germs can spread diseases when eaten.

b) Contaminated water – Diseases that spread through water are called water – borne diseases. For example, bilharzias and typhoid

c) Contaminated air – Air carrying germs when inhaled can spread diseases. Diseases that spread through air are called air-borne diseases. For example influenza, common cold and tuberculosis

d) Vectors – Vectors are organisms that spread diseases. Diseases that are spread by vectors are called vector – borne diseases e.g. Malaria, elephantiasis, yellow fever, plague, bilharzias etc.

e) Contact – Some diseases are spread through contact with the people suffering from the diseases or contact with their secretion or objects touched by them.

This disease that spread through physical contact are called contagious diseases. Examples of contagious diseases include chicken pox, whooping cough, HIVIAIDS, sexually transmitted diseases, Ebola etc.

The following are some of the common communicable diseases;

A) POLIOMYELITIS

Poliomyelitis is also called polio. It is an infectious disease that causes paralysis to infants (i.e., children below five years). Polio is caused by a virus called poliovirus.

Poliovirus can attack any part of the body especially the limbs and cause their deformation.

SYMPTOMS OF POLIOMYELITIS

An individual with poliovirus may have the following symptoms:

1. Headache, nausea, vomiting and general discomfort. These are early symptoms.
2. Slight fever for up to three days.
3. Stiff neck and back.
4. Muscles pains.
5. Paralysis, weakening and shrinkage of limbs. These are late stages.

SPREADING OF POLIOMYELITIS

Poliomyelitis spreads through oral ingestion, i.e. swallowing contaminated food and water. Poliovirus lives in the throat and the intestinal tract. Habits of defecating in water increase the rate of spreading the disease.

PREVENTION AND CURE OF POLIOMYELITIS

1. Poliomyelitis is prevented using vaccine. All children below 5 years should be vaccinated when they are 18 months old.
2. HYGIENITY of water and food helps to prevent the disease.
3. People should be educated for proper use of toilets and avoid defecating in the irresponsibly, in the bushes, etc.
4. The patient should be taken to hospital immediately for treatment.

EXERCISE

1. List five different examples of foods that should be included in a lactating mother’s meal.
2. What is good body health?
3. Give three ways through which we can keep the body in good health?
4. Indicate whether true or false.
5. We should wash our hands after visiting the toilet.
6. Clean and safe water is good for drinking.
7. We should play with dangerous animals.
8. Listening to music and making stories are ways of resting.

B) TUBERCULOSIS (TB)

Tuberculosis (TB) is an infectious disease that is caused by the bacteria called mycobacterium tuberculosis. This bacterium attacks any part of the body. The most common is lung tuberculosis, which affects the lungs, it is known as pulmonary tuberculosis.

SYMPTOMS OF TUBERCULOSIS

The following are some of symptoms of lung tuberculosis.

1. Dry cough, cough (sometimes producing phlegm) or coughing up blood.
2. Excessive sweating especially at night.
3. Fatigue (i.e. extreme tiredness or weariness).
4. Slight fever.
5. Loss of weight.

SPREADING OF TUBERCULOSIS

Tuberculosis spreads through the air. When a patient coughs, sneezes, or spills, the tubercle bacterial or mycobacterium tuberculosis which causes TB are left in the environment.

Using utensils that have been used by TB patients and drinking unpasteurized milk from an animal which is infected. Over-crowded houses with poorly ventilated rooms may spread the disease from the patient to a healthier person.

PREVENTION AND TREATMENT OF TUBERCULOSIS

Tuberculosis is a curable disease which can also be prevented.

Spread of TB can be prevented in the following ways:

1. Vaccination for prevention of TB.
2. Treatment of any case of TB. Treatment and medication of TB is currently free of charge in our county, Antibiotics is the medication used in the treatment of TB
3. Living in a well-ventilated house.
4. Avoid overcrowded places.
5. Isolate a TB patient until he/she is treated.

C) MEASLES

Measles is and infectious disease that attacks mainly children under 5 years of age. Measles is caused by a virus known as paramyxovirus. Measles is highly contagious disease. It is believed that 90% of people without immunity, who share a living space with a sick person, are in a danger of being infected. Measles is also called RUBEOLA

SYMPTOMS OF MEASLES

A person that is attacked by measles shows symptoms, usually 10 to 12 days after being exposed to the virus. The following are some symptoms.

1. High fever, which may rise up to 40°C or 40.5°.
2. Rashes starting on the face and ears, and then spread to other parts of the body.
3. Persistent dry cough.
4. Running nose.
5. Sore painful throat.
6. Reddening of the eyes or conjunctivitis which also cannot tolerate light.
7. Fatigue and tiredness.
8. Headache.
9. Swollen lymph nodes behind the neck.
10. Painful hand joints, wrists and knees.

SPREADING OF MEASLES

Measles spread when the patient coughs, sneezes, producing droplets from the running nose or mouth. The virus from the patient can remain in the air for about two hours. Measles is highly contagious.

PREVENTION AND TREATMENT OF MEASLES

Measles is prevented by getting vaccinated long before infection. Isolation of an infected child from other children is another way of prevention, since measles is highly contagious. Treatment of some complications caused by the disease is treated by medical doctors.

EXERCISE

1. Write the causes of tuberculosis
2. How is measles transmitted?
3. Mention two diseases that are associated with dirty and unsafe water.
4. What is food hygiene?
5. What are the three main types of foods? Give examples in each category.
6. What should the food of an elderly person have?
7. Give the function of vitamins and mineral salts in our bodies?
8. What advice would you give a lactating mother who is HIV positive?
9. (a) Who are adolescent children? (b) Why do they need special diet?

D) CHICKEN POX

Chicken pox is a viral disease which attacks mostly children below 12 years old. It forms an itchy rash with spots that look like blisters. The rashes spread all over the body. Different from rashes of measles, the chicken pox rashes are bigger in size and fewer. Chicken pox is caused by varicella zoster virus.

SYMPTOMS OF CHICKEN POX

A person that has chicken pox disease shows the following symptoms

1. Mild fever, which occurs before blisters have disappeared.
2. Blisters which are filled with puss and blood.
3. Rashes (i.e., red spots).
4. Headache and backache.
5. Sore throat.

SPREADING OF CHICKEN POX

Chicken pox spreads fast through air and by body contact with the patient.

PREVENTION AND TREATMENT OF CHICKEN POX

Chicken pox is effectively prevented through vaccination of children long before infection.

1. A sick person must be isolated from healthier ones.
2. Cleaning the body and clothes with soap and hot water after giving any service to a patient.
3. The patient should be attended by a doctor for treatment.

E) WHOOPING COUGH

Whooping cough is an infectious disease which is caused by bacteria. Whooping cough attacks mainly children under two years. Whooping cough is also known as PERTUSIS as it is caused by the bacteria which are called BORDETELLA pertussis.

SYMPTOMS OF WHOOPING COUGH

The patient gets the following symptoms:

1. Forceful coughs (i.e., five up to ten bad dry coughs) which are high-pitched with a “whooping” sound.
2. Uncontrollable fits. These come after a forced cough, which causes the patient to bend, twitch, and fail to breathe properly.
3. Sneezing and running nose.
4. Swelling of face.
5. Weak and weary.
6. Throat pain and hoarseness

SPREADING OF WHOOPING COUGH

Whooping cough is spread through air or contact with respiratory secretion of an infected person.

PREVENTION AND TREATMENT OF WHOOPING COUGH

Whooping cough can be prevented and treated through the following ways:

1. Vaccination, long before infection.
2. Isolation of the sick child from healthier ones.
3. Proper handling of sputum and mucus from the sick child.
4. Cleanliness of hands and clothes after attending to a sick child.
5. The patient should be taken to hospital for treatment.

EXERCISE

1. What causes the whooping cough?
2. Write ways in which whooping cough is transmitted
3. Explain how can we avoid whooping cough
4. Explain the symptoms of whooping cough

F) TETANUS

Tetanus is an infectious disease which tightens or contracts of skeletal muscles. Tetanus is also called lockjaw and is caused by the bacteria which are known as CLOSTRICIUM TETANI. These bacteria live in the soil, dust and animal dung. They penetrate into the human body through wounds or sores.

SYMPTOMS OF TETANUS

A patient who is suffering from tetanus has the following symptoms:

1. Tightening of the skeletal muscles which cause a person to bend backward.
2. Great pain due to prolonged Contraction of muscles.
3. High fever.
4. Jaw bones lock and the person fails to open up the mouth.
5. Pain in the spinal cord.
6. Failing to fold or straighten the arms and legs.

SPREADING OF TETANUS

The bacteria that cause tetanus live in the soil, dust, rust and in the animal dung. The bacterium enters the human body when a person with a wound, sore or open skin comes into contact with the object which contains the bacteria. Some children get tetanus during birth through the umbilical cord.

PREVENTION AND TREATMENT OF TETANUS

Tetanus can be prevented and treated through the following ways:

1. Vaccination should be given to small children.
2. Pregnant women should be vaccinated to protect unborn children from tetanus.
3. People should be vaccinated against tetanus.
4. Wounds or sores should be covered in order to avoid contacts with un-boiled water, dust, and soil, rust and animal dung.

EXERCISE

1. What causes the tetanus?
2. Write ways in which tetanus is transmitted
3. Explain how can we avoid tetanus
4. Explain the symptoms of tetanus

G) DIPHTHERIA

Diphtheria is an infectious disease which attacks mainly the throat, causing high fever and cold. Diphtheria is caused by bacteria which are called CORYNEBACTERIUM diphtheria. The bacteria attack the throat and cause difficulty in breathing.

SYMPTOMS OF DIPHTHERIA

A patient suffering from diphtheria experiences the following symptoms:

1. A sore in the throat, that causes difficulty in swallowing and breathing.
2. Swelling of the neck and the back.
3. High fever and headache.
4. Sores in other parts of the body, such as the mouth, the nose or the skin.

SPREADING OF DIPHTHERIA

Diphtheria should be treated and prevented since it can cause death when delayed.

The following are some of the prevention methods and treatment of diphtheria.

1. Vaccination should be given long before infection
2. Infected person should be treated in the hospital.
3. The patient should be isolated from healthier people.
4. Cleanliness of clothes and hands after attending to the patient should be adhered to.

EXERCISE

1. What causes the diphtheria?
2. Write ways in which diphtheria is transmitted.
3. Explain how can we avoid diphtheria?
4. Explain the symptoms of diphtheria.

(H) HIV/ AIDS

HIV is a virus that causes AIDS. The long form of HIV is human immunodeficiency virus.

AIDS is a disease that is caused by HIV. The long form of AIDS is acquired immunodeficiency syndrome.

TESTING OF HIV AND AIDS

Testing is the situation where by a person needs to assure the presence of HIV/AIDS in his or her body.

A person should go to the hospital, dispensary or specific are where HIV/AIDS testing is conducted so as to test his/her status.

Positive and negative in the blood sample

A person with positive blood sample indicates that a person has HIV while a person with negative blood test indicates that a person does not have HIV.

IMPORTANCE OF HIV TESTING

1. It helps to check the health status of an individual
2. It enables early start of ARV
3. A victim will be able to plan his/her personal or family life
4. If person tests negative, he/she will take precautions not to be infected
5. It helps to prevent HIV transmission from mother to baby
6. Reduce the rate of spreading of HIV infection.

TREATMENT OF HIV/AIDS

So far, no cure has been proved for treatment of HIV /AIDS. However, there are some ways used as treatment of HIV/AIDS.

Those ways are;

1. Medication
2. Counseling
3. Proper nutrition
4. Physical exercise

Medication

This involves medicine for curing the illness that caused AIDS patient at a certain stage is advised to start ARV (Anti-Retroviral) which boots the immunity.

Main things to be considered for anti-retrovirus (ARVs) users

ARV

These are drugs given to a person who lives with HIV so as to increase his/her immunity.

Counseling

This helps a patient psychologically. This should be done by professionals or experts.

Proper nutrition

A well-balanced diet is another important phenomenon in treating HIV/AIDS victims.

Physical exercises

Physical exercise makes a personal healthier. An HIV/AIDS patient is advised to do moderate exercises in order to make his or her body healthier.

THE IMPORTANCE OF TREATMENT OF HIV/AIDS

Treatment of illnesses that are associated with HIV/AIDS has the following importance to the individual patient, family, society and the nation.

1. Prolonging life: Provision of treatment enables the patient to live longer.
2. Reducing pain or suffering: Treatment of diseases related to HIV/AIDS reduces pain and suffering to the patient.
3. Makes the patient healthier: Treatment enables to increase the body immunity. This makes the HIVIAIDS gain weight and therefore look healthier.
4. Enables participation in economic activities: Treatment enables person living with HIVIAIDS to participate in economic activities, hence helping their family, society and the nation.
5. Human rights: Every person has the right to get treatment when he/she sick. Treatment of HIV/AIDS is one of the ways of fulfilling the human rights.
6. Makes the patient free from stress: Treatment of HIV/AIDS includes counseling. This makes the patient free from psychological problems such as stress and frustration.

EXERCISE

Answer the following questions.

1. What are ARVs?

2 Write the long form of ARVs.

3. Write any three advantages of taking ARVs.

4. How can you know whether someone has HIV virus?

5. When someone’s blood is detected with the HIV virus, the person is said to be

6. Mention three importance of carrying out an HIV- test.

7. Mention three main ways which HIV virus can spread from one person to a healthy person.

8. Mention two main body fluids where HIV can be found.

9. Write three main ways in which HIV virus can be prevented from spreading.

10. Why is AIDS said to be a dangerous disease

CHAPTER 2: DISEASES – SCIENCE STANDARD FOUR NOTES

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