Understanding the Various Types of Diseases: A Comprehensive Guide

This essay delves into the multifaceted world of diseases, categorizing them based on various factors such as their origin and the systems they affect. It begins by classifying diseases into infectious, deficiency, physiological, and genetic categories, providing examples for each. The essay then explores the body's immune system, differentiating between innate and adaptive immunity, and detailing how the body defends itself against pathogens through mechanisms like antibody responses and cell-mediated responses. Furthermore, it discusses methods to enhance body immunity artificially, including vaccination, supplementation, and physical exercise. The essay then examines viral and bacterial diseases in detail, focusing on Hepatitis B and tuberculosis, including their modes of transmission, symptoms, impacts on the body, and how the body fights these infections. The essay also covers the prevention and control strategies for these diseases, providing a comprehensive overview of disease types and immune responses.

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TYPES OF DISEASES
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Types of diseases
Any change of structure or function of an organism from normal associated with signs
and symptoms and not caused by physical injury is referred to as disease. The signs and
symptoms manifested in an organism usually indicate abnormalities.There are various types of
diseases. most are named based on the organism causing the disease. Diseases are categorized
based on several factors. They are classified into four groups
a) Infectious diseases are caused by organisms for example bacteria, parasite, virus or fungi
for example malaria
b) Deficiency diseases are due to lack of nutrients for example rickets due to lack of vitamin
D
c) Physiological diseases caused by malfunction of organs for example asthma
d) Genetic diseases are caused by inherited genes that is genes carrying information about a
disease are transferred to the generations for example sickle cell disease
Category Examples
Infectious diseases Meningitis, chicken pox, influenza, lungworm
Deficiency diseases Scurvy, anorexia
Genetic diseases Obesity
Physiological diseases Cancer
Diseases can also be classified based on other factors:
Topographic- the region or system affected for example urinary tract disease

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Anatomic – organ or tissue affected for example kidney disease
Methods of enhancing body immunity artificially
The ability of the body to fight against diseases is termed as immunity (Tiegs and Lohse
2010, p.2). The body has the ability to resist invasion from viruses, bacteria or any other external
factors. The body immune system is in two parts. That is, innate immunity and adaptive
immunity. Innate immunity is non-specific response of the immune response. It deals with
known threats or pathogens. The skin plays a major role in this type of immunity. The skin
protects the inside environment from the outside. The internal epithelial layer of the skin
contains a mucus layer that secret mucin and glycoproteins which help to prevent pathogens
from invading the epithelium layer of the skin. The protein produced also help to inhibit growth
of the pathogens and destroys them. Whenever the skin experiences an injury, the blood at the
wound cite clots, the clotting is facilitated by the converting of fibrinogen by thrombin to fibrins
which are in strand form through the help of vitamin K and forms a layer on the surface of the
skin called clot. The clot also acts as a protective layer that inhibits entrance of the pathogens
into the blood stream. In adaptive immunity that is also called the acquired immunity, the
immune system work on a specific pathogen. The white blood cells(lymphocytes) fights against
the pathogen. Here two responses play part (Mantovani, Cassatella, Constantini and Jailon 2011,
p.519). That is, antibody response and cell mediated response. The B cells are activated to
produce antibodies that binds with the pathogen. The binding inactivates the pathogen and make
it impossible to attach to the body cell (Vivier et al 2011,p. 46). Then through phagocytosis the
antigen is eliminated from the body. In the cell mediated response, the T cells that are on the cell
acts against the antigen. Incase a cell is invaded by the antigen, the T cells destroys the host cell

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carrying the antigen to stop its replication.In this acquired immunity a host receives antibodies
from an external source. For instance, the injection done during immunization. When a host
acquire immunity by introduction of antibodies, the body develops immunity against a specific
pathogen permanently. However, there are methods that are used to boost the immunity
artificially. They are
a) Vaccination and immunization
b) Supplementations
c) Physical exercise
d) Eating balanced and appropriate diet
In vaccination and immunization, a dead microbe is introduced into the body that it
stimulates the body immunity. This enables the body to acquire immunity against a certain
disease for example in the vaccination against chicken pox for instance the injection of protein
properdin has shown enhancement of the body immunity to destroy meningitis bacteria.
Vaccination against the influenza and the lungworm has been effectively implemented with
success.
Supplementations of nutrients that are deficient in the body also enhances body
immunity. Nutrition plays a big role in the body immunity. Nutrients such as fat-solublevitamins
(A, D, and E), iron and folic acids play a major role in the immunity of the body. Therefore,
incase of deficiency, the immunity is compromised. Supplementation help to provide the
recommended daily intake of these nutrients. For example, supplementation of iron to reduce
anemia. In the case of scurvy supplementation of vitamin c in the body can be done through
increased intake of fruits.

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Physical exercise increases the energy output. Due to lifestyle the energy output and
metabolic rates have reduced. This has led to increase in weight that leads to malnutrion-
overnutrion. Therefore, the exercise helps to reduce the excess fat and keeping good weight.
This has shown improvement of the body immunity. For example, in obesity that is lifestyle
caused, exercise help to reduce the body mass index.
A balanced diet that is, food that contains all the nutrients for example protein,
carbohydrates, vitamins and fat. This diet enables the body to receive all the nutrients necessary
for growth and repair. This therefore ensures that the necessary nutrients for enhancement of the
immunity are available. For example, adapting a habit of eating foods rich in anti-cancerous
elements, will help to increase immunity against cancer.
In infectious diseases, there are microorganisms that causes the diseases namely
a) Virus
b) Bacteria
c) Parasites
Viral disease
A virus is a microscopic biological organism that attacks, destroy and causes dysfunction
of the body cell to cause a disease. A virus basic structure has a core that consist of nucleic acid
that forms the genetic information in form of an RNA or a DNA, a protein layer called capsid
protects the nucleic acid. As Jackson and Bartek (2009) explained that when a virus gets into the
host’scells, it replicates and spread to other cells. The multiplication process is rapid. Presence of
virus DNA OR RNA components in the host cell DNA structure, causes the dysfunction of the
cell. At this point the disease is formed (p.1071). However, the body immunity fights the

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pathogen by producing antibodies.Some virus may last in the body for one to two weeks as the
body try to fight it. Examples of common viruses that causes diseases are: Rota virus that causes
diarrhea in infants and children, herpes virus that causes genital warts, yellow fever virus that
causes yellow fever, human papillomavirus that causes cervical cancers and human
immunodeficiency virus that causes Aids. As asserted by Jordheim, Durantel, Zoulim and
Dumontet (2013),viruses affect any part of the body (p. 447). However, there are some viruses
that do not cause diseases in humans.
Mode of Transmission
Viruses can be transmitted through several routes:
a) Skin contact for example human papillomavirus
b) Air for example cold viruses
c) Fecal matter for example hepatitis A virus
d) Sexually for example human immunodeficiency virus
e) Animal bites for example rabies
For instance, hepatitis B virus that affects the liver is transmitted through contact with
blood or body fluids of a person infected with the disease, having unprotected sex and sharing
sharp objects such as needles and razor blades with people with hepatitis B disease. As according
by Sung, Tsoi, Wong and Chan (2008), body fluids such as blood and serum has high
concentration of infectious hepatitis B virus (p.1070). A mother can transmit the hepatitis B virus
to the infant during delivery. Blood donation from people with Hepatitis B is prohibited since it
can spread the disease through blood transfusion.
Symptoms of Hepatitis B disease and impact to the body

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In acute Hepatitis B disease, symptoms include fatigue, loss of appetite, nausea, jaundice,
pain in the upper right abdomen due to inflammation of the liver and in case of a chronic
hepatitis B disease other symptoms such as body weakness, weight loss and impaired vision
especially at night are frequently experienced. However, these symptoms are not visible in
Hepatitis B carriers (sorrel et al 2009, p.3).the carrier is in a position to infect others especially
the sexual partner.
Due to reduced appetite the body uses the store energy for its metabolic activities. This leads to
weight loss which eventually lead to malnutrion. There is reduced absorption of vitamin A and D
this leads to impaired visions and osteoarthritis (Liaw and Chu 2009, p. 590). In chronic hepatitis
B disease, it leads to liver disease for example liver cirrhosis that makes the liver to harden due
to loss of cells, liver failure or liver cancer which can eventually lead to liver transplant or death.
How the body fight Hepatitis B
The body fight hepatitis B through cell mediated and humoral immune response. The
infection by the virus is recognized by the T-cells which activates the cell receptors and
production of antiviral cytokines interferons. The interferons inhibit the replication of the
virus and activates the killer T-cells to destroy the infected hepatocytes (Ebert et al 2015,
p. 5807). This controls the infection and generates memory response
Prevention and control of hepatitis B
Hepatitis prevalence in UK is low. However, preventive measures of testing and
vaccination are regularly conducted to ensure that the disease is not spread. However, little is
known about the disease in Africa especially the west Africa (Spearman et al 2017, p.901). there
education to the public and the health care provider is necessary as well as testing and

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vaccination. The Hepatitis B can be control b going through treatment to clear the virus from the
body.
Bacterial disease
Bacteria are unicellular microorganism. And are characterized by their shape and size.
For instance, cocci bacteria which are spherical in shape for example the Staphylococcus aureus
that natural grows in human skin and nose with no harm. However, they are known to cause
diseases such as pneumonia. The bacillus which are rod shaped bacteria for example Escherichia
coli found in the gastrointestinal tract. However, they cause infections in other sites in the body
for example in the urinary tract they cause urinary tract infection. The vibrio bacteria which are
in spiral form. They are found in aquatic places for example Vibrio cholerae that causes cholera.
When the bacteria get into a host cell they multiply through cell division and an increase in their
number leads to development of a disease.
Mode of transmission
Bacterial infection is transferred through the following modes
a) Direct contact with a person or an animal that has the infection
b) Insect bite for example misquotes which carries bacteria causing diseases
c) Contact with surfaces that contain the bacteria and then touching parts of the body
d) Food contamination by bacteria. The bacteria can grow in food and produce toxins (food
intoxication) or one can ingest food that contain bacteria that then leads to infection.
e) Air. Some bacteria can be spread through air for example tuberculosis is an air borne
disease.

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For instance, tuberculosis infection which affects the lungs, spine, brain or the kidney is
transmitted by air. The mycobacterium tuberculosis bacteria are spread from a person with active
Tb when he coughs, sneeze or speak. As according to Mlay, Luboobi, Kuznetsov and Shahada
(2015), tuberculosis is highly transmitted in highly populated regions (p.198).
Symptoms of tuberculosis and its impact in the body
People infected with tuberculosis have symptoms such as fatigue that is associated with
weakness, unintentional weight loss, fever, night sweats, cough that last more than three weeks,
chest pain and shortness of breath.
Tuberculosis has shown detrimental effect in vitamin C and E in the body. As according
toJohnKennedy, Augustin and Ikechukwu (2012), the vitamin C and E were seen to be depleted
in patients with Mycobacterium tuberculosis. This therefore suppresses the immunity and make
the body susceptible to diseases (p.3). tuberculosis infection can lead to acculation of fluid in the
lungs hence reducing the volume of the lungs and causing chest pain. It can also infect other
organs and causing some major body problems.
How the body fight tuberculosis
The body fight tuberculosis through adaptive cellular mediated response. The T-cells
specific for Mycobacterium tuberculosis recognizes the presence of the bacteria in the body. The
cells multiply and move to the lungs and produce cytokines. Though this is slow to be induced
and expressed in the lungs (Shi and Pamer 2011, p.726). the cytokines activates and enable the
macrophages to restrain the bacteria from replicating or kill it.
Prevention and control of tuberculosis

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The prevalence of tuberculosis in highly populated areas like slums is high, therefore it is
necessary to take preventive measure to stop its spread and to stop deaths. Vaccination in
children should be done. this is done at the early stage of life where BCG is injecting to infants.
However, vaccination is not effective in adults and therefore training on the causes, symptoms
and preventive measures should be taught to the community, health providers and patients. a
patient who cough for more than two weeks should be tested if the test turns positive should start
treatment immediately. Frequent testing in the communities should be implemented. This
preventive and control measures are applicable both in the UK and in other parts of the world.
Parasitic disease
A parasite is an organism that lives and feeds from another organism and giving nothing
in return. The parasite attach itself on a living organism and obtain nourishment from it.
Eventually the parasite may cause a disease in its host. Parasites that live inside the host are
referred to as endoparasite while those that feed on other parasites are referred to as epiparasite.
For instance, the tapeworm that attaches itself on theinside of the host intestine and obtains
nourishment from feeding on the partially digested food and the fleas that attaches itself in other
animals and obtains nourishment by sucking blood from the host causing itching of the skin. The
parasite grows, reproduce and may invade the host and hence causing a disease that is termed as
parasitic infection. The infection in human can be caused by protozoa- a endoparasite single
celled organism which causes giardiasis, helminths- a endoparasite multi-cellular organism for
example tapeworm, ring worm, round worm and ectoparasites- lives outside the body for
example ticks, fleas and mosquitoes.
Modes of transmission

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Parasitic infections are transmitted in various ways.
a) Insect bites for example parasitic protozoa spread by mosquitoes to cause malaria
b) Contaminated food and water for example food contaminated with protozoa and
helminths
c) Contact with animals carrying parasites for example cats and dogs which carries parasite
that cause bartenollosis. The fleas on the pest acts as host to tapeworms which can be
transferred to humans.
d) Sexual contact. Some parasites are transferred in sexual contact for example
trichomoniasis
For instance, Malaria is a deadly parasitic infection that is spread through bites. It causes
mortality at high rate globally. As according to Chico, Mayaud, Ariti, Mabey, Ronsmans and
Chandramohan (2012), malaria has highly contributed to stillbirth and miscourages in pregnant
women (p. 2080). People at high risk of acquiring these diseases are the children below five
years and the old people. This is because their immunity is compromised.
Symptoms of malaria
For instance, Malaria is a parasitic infection that is spread through bites. Major symptoms
manifested in people suffering from malaria are high fever, sweating, persistent headaches,
vomiting, diarrhea, poor appetite, dehydration, moderate to severe chills and weight loss
The malaria caused by Plasmodium falciparum causes destruction of the body’s red plod cells
causing hemolytic anemia which can lead to death. It is estimated that 40% of pregnant women
are highly exposed to malaria infection(Staines and Krishna 2012, p.2).Malaria is also known to

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induce renal lesions that leads to kidney failure. It also causes pulmonary edema, cerebral
malaria may lead to coma or death
How the body fights malaria
The body fights malaria by producing antibodies that block the invasion by malaria
parasite and adhesion to the tissue to attain antiparasitic immunity. The platelets also produce
platelets factor 4 that combines with the red blood cells molecules to block and sdestroy the
plasmodium falciparum parasite. Through the cell mediated response, the macrophage activation
is achieved to destroy the parasite (Rowe, Claessens, Corrigan and Arman 2009, p.11).
Prevention and control of malaria
Malaria is a deadly disease that kill people daily globally. Appropriate measures for
prevention and control should be implemented. It can be prevented through various means.
Vector control is the best preventive mechanism. This appropriately work in UK. This can be
achieved by sleeping under treated nets. The treatment should be done at regular intervals to
ensure efficient protection. Regular treatment of pregnant women during the antenatal clinic and
children with antimalaria drugs will help to prevent this disease. Most affected areas especially
the Sahara region of Africa consist of poor and uneducated people. Therefore, education on how
to prevent malaria should be done to communities to create awareness. To control the disease
proper diagnosis and treatment is fundamental.
Conclusion
Diseases attack the body and causes various symptoms that indicates the abnormality of
the body. However, the body respond through its immunity to eliminated the antigen. The body
immunity is in two parts. That is the innate immunity and adaptive immunity. The innate