CND: MODULE 1: INTRODUCTION TO CDS

 INTRODUCTION TO THE COURSE

Welcome to CNCDs,  In this course you going to learn about various forms of diseases and how to represent them if you are affected by them.    You will learn more on the symptoms and signs of each disease and how you control them. It is important to learn about diseases because a better understanding of epidemics will help you to detect an outbreak or epidemic of a communicable disease and report it immediately to the Health Centre and/or District Health Office. You are also expected to help the District Health Team in the control.This course introduces you to different kind of disease that are communicable to man and how to prevent them.

 The aim of this course is to  apply knowledge and skills of communicable and non-communicable diseases in a professional attitude

1.Definition of terms used in communicable and non-communicable diseases

Communicable disease – An illness due to a specific infectious agent or it toxic products, which arises through transmission of that agent or its products from a reservoir to a susceptible host, either directly s from an infected person or animal, or indirectly through the agency of an intermediate plant or animal host, a vector, or the inanimate environment (see 44, Transmission of Infectious Agents).

Communicable disease – An illness due to a specific infectious agent or it toxic products, which arises through transmission of that agent or its products from a reservoir to a susceptible host, either directly s from an infected person or animal, or indirectly through the agency of an intermediate plant or animal host, a vector, or the inanimate environment 

Non-communicable disease (NCD) is a medical condition or disease that is non-infectious or non-transmissible. NCDs can refer to chronic diseases which last for long periods of time and progress slowly. Sometimes. 

Quarantine – (1) Complete quarantine  is the limitation of freedom of movement of such well persons or domestic animals as have been exposed to a communicable disease, for a period of time equal to the  to the longest usual incubation period of the disease, in such manner as to prevent effective contact with those not so exposed.

Isolation- means that the person with the disease is not allowed to come into close contact with other people, except those who are providing care. It is used to control highly infectious and serious conditions or diseases.

Incubation period – The time interval between the infection of a susceptible person or animal and the appearance of the first sign or symptom of the disease in question.

Carrier – A carrier is an infected person who harbors a specific infectious agent in the absence of discernible clinical disease and serves as a potential source of infection for man.  The carrier state may occur with infections inapparent throughout their course (commonly known as healthy carriers), and also as a feature of incubation period, convalescence, and post-convalescence of a clinically recognizable disease (commonly known as incubatory and convalescent carriers).  Under either circumstance the carrier state may be short or long (temporary or chronic carriers) the same applies to other vertebrate animals.

 Susceptible – A person or animal presumably not possessing resistance against a particular pathogenic agent and for that reason liable to contract a disease if or when exposed to such agent. 

Latency period-

 DISEASE AGENTS.

In this section, we are now going to describe some of the common disease agents like Viral, Bacteria, Parasitic and Fungal.

Viral

 Any of various extremely small, often disease- causing agents consists of a particle (the virion), containing a segment of RNA or DNA within a protein coat knows as a Capsid. Viruses are not technically considered living organism because they are devoid of biological processes (such as metabolism andrespiration) and cannot reproduce on their own but require living cell (of a plant, animal or bacterium) to make more viruses reproduce first either by injecting their genetic material into the host cell or by fully entering the cell and shedding their protein coat.

The common cold, influenza, chickenpox, small pox, measles, mumps, yellow, haemorrhagic fever and some cancers are among the diseases caused by viruses.

Bacteria 

Single –celled microorganisms that can exist either as independent (free- living) organisms or as parasites (dependent on another organism for life). Examples of bacteria include Acidophilus, a normal inhabitant of yogurt. Gonococcus which causes gonorrhoea, clostridium welchii, the most common cause of gagregen ,E coli, which lives in the colon and can cause disease elsewhere, and streptococcus, the bacterium that causes the common throat infection called strepthroat.

 Parasitic 

Parasites are living things – like your body- for food and a place to live. You can get them from contaminated food or water, a bug biteor sexual contact. Some parasitic diseases are easily treated and some are not. Parasites range in size from tiny, one- celled organisms called protozoa to worms that can be seen within the naked eye.There are no vaccines for parasitic diseases. Some medicines are available to treat parasitic infections.

Fungal

Fungus: A single –celled or multi-cellular organism. Fungus can be true pathogens (such as histoplamosis) and coccidiodomycossis) that cause infections in healthy persons or they can be opportunistic pathogens (such as aspergillosis, candidiasis , and cryptococcossis that cause infections in immune  compromised person (including cancer patients, and persons with ( AIDs) .  An example of a common fungus is yeast organisms which causes thrush.

Fungi are also used for the development of antibiotics, antitoxins and other drugs used to control various human diseases.

 DISEASE CONTRIBUTING FACTORS

In our early section we looked at the disease  agents  . in this section we will deal with factors which contribute to the manifestation of the disease.

Host factors:

Host factors you are talking of an affected individual; Host you are talking of Animal, including human, which gives support to and provides a living environment for an infectious agent.The below factors determines the way individual will react a disease. 

 Socio-economic,

Under socio-economic factor you are talk about how societal or social statuses affect individuals. This will include a complex mixture of interacting which includes cultural and other environmental parameters.

      Age, Sex

Age, Sex and genetic susceptibility are modifiable. Many of the risks associated with age and sex are modifiable. Such risks includes behavioural factors ( e.g Physical inactivity, age ( older, children )  are susceptible or prone to infections.

Sex,(gender) there are some diseases that affect certain category of                                  humans may be because of their biological make up.

Nutrition, - Diet and nutrition are important factors in the promotion and maintenance of good health throughout the entire life course.

Immune status: individual and herd immunity); 

Agent factors; 

           Drug resistance, 

Drug resistances basically mean ability of bacteria and other microorganisms to withstand a drug that once stalled them or killed them. In other words is the reduction in effectiveness of a drug in curing a disease or condition.

Load, and e.g Viral load the severity of a viral infections and can be calculated by estimating the amount  of virus in an involved body fluid.            

Strain

Environmental, Geo-political, and Climatic changes

Here you are going to look at the combination of geographic and political factors influencing or delineating a country or region. National policy based on the interrelation of politics and geography.

Summary of the Unit 

We have come to the end of this Unit. In this Unit we defined key terms used in communicable and non-communicable diseases. Communicable disease refers to the diseases that spread person to person or from animals to people. while non-communicable disease refers tois a medical condition or disease that is non-infectious or non-transmissible.We also discussed the four main disease agents that is the Viral, Bacterial. Parasitic and Fungal. We ended the lecture by discussing that the main contributing factor for disease manifestation includes the host factors, agent factors and environment factors.