Immunology is the study of the immune system and is a very important branch of the medical and biological sciences. The immune system protects us from infection through

1. Communicable And Non-
communicable Diseases
Lecturer 1

2. • This module is composed of three units namely:
• Unit One: Concepts of Communicable and Non-Communicable Diseases.
• Unit Two: Types of Communicable Diseases.
• Unit Three: Types of Non-Communicable Diseases.

3. • By the end of this module, you will be able to:
• Discuss different concepts of communicable and non-communicable diseases
• Discuss types of communicable diseases
• Discuss types of non-communicable diseases
Module Objectives

4. • Welcome to the first unit of this module. In this unit you will define key terms
used in communicable and non-communicable diseases and also differentiate
between communicable and non-communicable diseases.
Unit One: Concepts of Communicable and Non-Communicable Diseases

5. • By the end of this unit, you will be able to:
• Define terms commonly used in communicable and non-communicable diseases
• Classify communicable and non-communicable diseases
Unit Objectives

6. • You will start by defining the key terms used in communicable and non-communicable diseases. These terms include the following:
• Communicable.
• Non-communicable diseases.
• Etiology.
• Incubation.
• Manifestation.
• Control of diseases.
• Prevention of diseases.
• Primary prevention, secondary prevention and tertiary prevention.
• Emerging diseases.
Definition of Key Terms

7. • Re-emerging diseases.
• Vector.
• Reservoir.
• Fomite.
• Host.

8. • Communicable diseases are diseases that are transmitted through direct contact with an
infected individual or indirectly through a vector.
• Communicable disease can also be referred as contagious disease. Examples include the
following:
• Malaria is transmitted from an infected ‘person to another person through a vector
known as a mosquito’.
• Scabies is a skin condition that is transmitted from an infected person to another person
through contact.
Communicable Diseases

9. • Non-communicable diseases (NCDs) are also known as chronic diseases. These diseases
are not passed from person to person and tend to be of long duration with slow in
progression.
• Examples include the following:
• Hypertension is an example of a non-communicable disease. It is not transmitted from
one person to another. It is also a chronic disease, that is, patients tend to have the
disease for a long time.
• Cancer is another NCD which cannot be transmitted from person to person.
Non-Communicable Diseases

10. • Etiology is a branch of medical science concerned with the causes and origins of
diseases. For example:
• The etiology of malaria is the protozoan plasmodium
Etiology

11. • This is the development of an infection from the time the pathogen enters the
body until signs or symptoms first appear. For example, the incubation period for
malaria is 14-21 days from the time one is bitten by a mosquito to the onset of
signs and symptoms of malaria.
Incubation

12. • This refers to a reduction in the incidence, prevalence, morbidity or mortality of
an infectious disease to a locally acceptable level. For example, the reduction of
the number of people infected with a disease from a high number such as 20000
infections to a tolerable level, for example 1000 infections.
Control of Diseases

13. • This is an obvious indication or specific evidence that a disease is present. It is
also known as a symptom. For example a high fever is an early manifestation of
malaria.
Manifestation

14. • This refers to a reduction in the incidence, prevalence, morbidity or mortality of
an infectious disease to a locally acceptable level. For example, the reduction of
the number of people infected with a disease from a high number such as 20000
infections to a tolerable level, for example 1000 infections.
Control of Diseases

15. • Disease prevention covers measures not only to prevent the occurrence of
disease, such as risk factor reduction, but also to arrest its progress and reduce its
consequences once established.
Prevention of Diseases

16. • Primary prevention refers to preventive measures that stop the onset of illness or
injury. This practice focuses on the identification of potential risk factors for
disease or disability in healthy individuals, for example, wearing seatbelts and
immunisation.
Primary Prevention

17. • These are measures aimed toward the early detection of underlying disease when obvious clinical symptoms
are not yet apparent.
The goal is to slow progression of a disease or in the case of an injury, limiting long-term disability or
preventing re-injury. Examples include the following:
• Screening and detection of cancer, such as pap-smear and initiation of early treatment.
• Mother attending maternal child health clinics to be screened for syphilis, if found to be positive the clinician
will initiate appropriate treatment.
Secondary Prevention

18. • Tertiary prevention is when treatment is implemented after the disease becomes symptomatic.
Focus is helping people manage chronic health problems and preventing further deterioration of
disease or disability.
• Examples are the following:
• Surgery to treat lung cancer, rehabilitation after a stroke, and cardiac rehabilitation post-
myocardial infarction.
• Patients with diabetes mellitus should be given insulin to maintain low blood sugar to avoid renal
failure.
Tertiary Prevention

19. • An emerging disease is one that has appeared in a population for the first time, or
that may have existed previously but is rapidly increasing in incidence or
geographic range (WHO, 2015).
• Examples of emerging diseases in Africa include Ebola, avian flu, small pox and
anthrax.
Emerging Diseases

20. • This is any condition usually an infection that reappears after it had been
eradicated or brought under control. For example, cholera, dengue, diphtheria
and tuberculosis
Re-emerging Diseases

21. • A host is a person or animal that gives subsistence to an infectious agent under
natural conditions.
• For example; the host of plague is a rat and the host of leishmaniasis is mainly
canines and rodents.
Host

22. • Vector is an invertebrate or an animal capable of transmitting an infectious agent
to vertebrates. For example the following:
• A flea is a vector of plague
• Mosquitos are vectors of malaria
Vector

23. • Reservoir is anything whether living or inert, in which an infectious agent lives
and multiples in such a manner that it can be transmitted to a susceptible host.
• Examples include the following:
• The reservoir host for trypanosomiasis is wild herbivore
• The reservoir host for yellow fever is wild monkeys
Reservoir

24. • Fomites are non-living things which harbour and transmit infectious agents to a
susceptible host. Examples are patient’s cloths and contaminated food (Nordberg, 2005).
• By now, you should know the meaning of some of the common terms you will be using in
this course. Next you will look at the classification of communicable and non-
communicable diseases.
Fomites

25. • You will start by looking at the classification of communicable diseases followed
by that of non-communicable diseases.
Introduction

26. • You will now learn about the classification of communicable diseases. This is a
disease that is transmitted through direct contact with an infected individual
or indirectly through a vector.
• Communicable diseases can also be referred to as contagious disease.
Communicable disease can be classified in the following ways:
• Sexually transmitted diseases
Classification ofCommunicableDiseases

27. Conti….
• Diseases affecting the gastro-intestinal system
• Airborne diseases
• Systemic protozoan diseases
• Infection affecting the skin
• Infections affecting the central nervous system

28. • Sexually transmitted diseases are classified as follows:
• Sexually transmitted diseases associated with discharge production for
example: Gonorrhoea, chlamydia, trichomonas vaginalis.
• Sexually transmitted diseases associated with ulcer formation for example:
Syphilis, chancroid and lymphogranuloma venereum.
SexuallyTransmittedDiseases

29. • Diseases affecting the gastro-intestinal system are classified as follows:
• Bacterial diseases that affect the gastrointestinal system. For example: Cholera,
bacillary dysentery (shigellosis) and typhoid fever.
• Protozoan diseases that affect the gastrointestinal system. For example:
Amoebioasis and giardiasis.
• Helminthic diseases that affect the gastrointestinal system. For example, Ascaris
lumbucoids hook worm and taeniasis.
DiseasesAffectingtheGastro-IntestinalSystem

30. • Airborne diseases are spread through the air and affect the breathing
system. Examples include:
• Pulmonary tuberculosis
• Pneumonia
• Upper respiratory tract infections.
AirborneDiseases

31. • Systemic protozoan diseases are diseases that affect the whole body. Examples
are malaria, leishmaniasis, and trypanosomiasis.
SystemicProtozoanDiseases

32. • Infection affecting the skin includes scabies, and dermatological fungal infection.
InfectionAffectingtheSkin

33. • Infections affecting the central nervous system include diseases that affect the
brain and spinal cord. For example meningitis.
InfectionsAffecting theCentralNervousSystem

34. • Communicable disease can also be grouped into emerging diseases and re-emerging
diseases. Emerging diseases include the following:
• Monkeypox virus
• Rift valley fever virus
• Filiovirus
• Vibrio cholerae o139
• Penicillin-resistant streptococcus pneumonia
GroupsofCommunicableDiseases

35. • Re-emerging diseases include the following:
• Malaria
• Tuberculosis
• Yellow fever
• Trypanosomiasis
Conti…..

36. ClassificationofNon-communicableDiseases
• You will now learn about the classification of non-communicable diseases.
Non-communicable diseases (NCDs) are also known as chronic diseases.
• These diseases are not passed from person to person. They last for long
periods of time generally progress slowly. Non-communicable disease can be
classified in the following ways:

37. Conti…..
• Non-communicable diseases affecting the cardiovascular system
• Non-communicable diseases affecting the gastrointestinal system
• Non-communicable diseases affecting the central nervous system
• Non-communicable diseases affecting the renal system
• Non-communicable diseases affecting the endocrine system

38. Conti…….
• Conditions associated with malnutrition
• Non-communicable diseases affecting the respiratory system
• Common cancerous conditions
• Common injuries

39. ConceptsofCommunicableandNon-CommunicableDiseases
Classification Description Examples
Non-communicable diseases affecting the cardiovascular
system.
These are the diseases that affect the heart and blood vessels. Examples include hypertension, coronary Disease and valvular
heart diseases.
Non-communicable diseases affecting the gastrointestinal
system
These are diseases that affect the digestive system. Examples include gastric ulcer disease, peptic ulcer disease
ulcerative colitis
Non-communicable diseases affecting the central nervous
system
These are diseases that affect the brain and the spinal cord Examples include Psychiatric illness cardiovascular accident.
Non-communicable diseases affecting the renal system These are diseases that affect the kidney and urinary tubules Examples include renal failure, acute glomerular nephrites and
nephritic syndrome.
Non-communicable diseases affecting the endocrine system These are diseases that result from an increase or decrease in
the amount of hormones produced in the body
Examples include diabetes mellitus, thyrotoxicosis, Addison’s
disease.
Conditions associated with malnutrition
These are diseases that are due to either under nutrition or over
nutrition
Examples include Kwashiorkor, marasmus and obesity.
Non-communicable diseases affecting the respiratory system These are diseases that affect the breathing system Examples include asthma, chronic obstructive air way disease
and pulmonary embolism.
Common cancerous conditions These are disease that results from abnormal cell development These are disease that results from abnormal cell development
Common injuries These are diseases that result from trauma emanating from
varied causes
Examples include soft tissue injuries and fractures.

40. •END