Human Diseases Caused by Bacteria Viruses Protozoa Fungi

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Human diseases can be caused by various pathogens, including bacteria, viruses, protozoa, and fungi. Here are examples of diseases caused by each group:

Invisible Invaders: A Compendium of Human Diseases Caused by Microorganisms

The human body is a complex ecosystem teeming with microorganisms, both beneficial and harmful. While some microbes help us digest food, produce vitamins, and fight off pathogens, others can cause a wide range of diseases. Here’s a glimpse into some major human diseases caused by different types of microorganisms:

Diseases Caused by Protozoa


#1 Malaria

Symptoms: Fever with shivering

Parasites: Plasmodium

Carrier: Female Anopheles Mosquitoes

Affected Organs: Red Blood Corpuscle (RBC) and Liver.

#2 Kala-ajar

Symptoms: High fever

Parasite: Leishmania-donovani

Carrier: Sand Flies

Affected Organs: Bone marrow

#3 Sleeping Sickness

Symptoms: Fever with severe sleep

Parasite: Trypanosoma

Carrier: Tse-Tse Flies

Affected Organs: Brain

#4 Diarrhoea

Symptoms: Mucous and Diarrhoea with blood

Parasite: Entamoeba histolytica

Spread Through: contaminated food or drinking water, or from person to person:

Affected Organs: Intestine

Disease Caused by Bacteria:


#1 Tetanus

Symptoms: High fever, spasms in body, Closing of jaws, etc.

Name of Bacteria: Clostridium Tetani

Affected Organs: Nervous system

#2 Cholera

Symptoms: Contentious stool and vomiting

Name of bacteria: Vibrio cholera

Way of Transmission: One can be infected by drinking water or eating food contaminated by the bacterium

Affected Organs: Intestine

#3 Typhoid

Symptoms: High fever, Headache

Name of bacteria: Salmonella typhosa

Way of Transmission: It is transmitted by the consumption of contaminated food or water.

Affected Organs: Intestine

#4 Tuberculosis (TB)

Symptoms: Repeated coughing.

Name of bacteria: Mycobacterium tuberculosis

Way of Transmission: It is spread through the air or the flu. Someone having TB who coughs, sneezes, talks, laughs, or sings then germs are released.

Affected Organs: Lungs

#5 Diphtheria

Symptoms: Difficulty in respiration and suffocation.

Name of bacteria: Corynebacterium diphtheriae

Way of Transmission: It spreads through respiratory droplets, like, from coughing or sneezing.

Affected Organs: Respiratory tube

#6 Plague

Symptoms: Very high fever, muscular eruption on the body.

Name of bacteria: Pasteuralla pesties

Way of Transmission: Bite of infected vector fleas like rats.

Affected Organs: Lungs, area between the two legs.

#7 Whooping cough

Symptoms: Continuous coughing

Name of bacteria: Hemophilis pertussis

Way of Transmission: coughing or sneezing of infected persons

Affected Organs: Respiratory system

#8 Pneumonia

Symptoms: High fever, swelling in lungs

Name of bacteria: Diplococcus pneumonia

Way of Transmission: spread via air-borne droplets from a cough or sneeze

Affected Organs: Lungs

#9 Leprosy

Symptoms: Spot on body, nerves affected

Name of bacteria: Mycobacterium leprae

Way of Transmission: close contact with someone with untreated leprosy over many months

Affected Organs: Nervous system Skin

#10 Gonorrhea

Symptoms: Swelling in urinary path

Name of bacteria: Neisseria Gonorrhoeae

Affected Organs: Urinary path.

Disease Caused by Viruses:



Symptoms: Immune system of body became weak

Name of virus: HIV

Way of Transmission: through sexual behaviors and needle or syringe use. blood, semen, pre-seminal fluid, rectal fluids, vaginal fluids, and breast milk

Affected Organs: Defensive system, White Blood Corpuscle WBC

#2 Dengue Fever

Symptoms: Pain in eyes, muscles, head and joints.

Name of virus: DENV

Way of Transmission: Bite of an infected mosquito

Affected Organs: Whole body particularly head, eyes and joints.

#3 Polio

Symptoms: Fever, body pain, backbone and intestine cells are destroyed.

Name of virus: Pilio virus

Way of Transmission: direct contact with someone infected with the virus

Affected Organs: Nerve, backbone

#4 Influenza (flu)

Symptoms: Suffocation, sneezing, restlessness.

Name of virus: Miso virus

Way of Transmission: direct contact, by inhalation of virus-laden aerosols.

Affected Organs: Whole body

#5 Chickenpox

Symptoms: High fever, reddish eruption on body

Name of virus: Variola virus

Way of Transmission: by direct contact (touching the rash), droplet or air born spread (coughing and sneezing) of vesicle fluid

Affected Organs: Whole body

#6 Smallpox

Symptoms: Light fever, eruption of bile on body

Name of virus: Varcella virus

Way of Transmission: direct deposition of large, infective airborne droplets of saliva onto the nasal, oral or pharyngeal mucosal membranes

Affected Organs: Whole body

#7 Rabies

Symptoms: The patient becomes mad with sever headache and high fever.

Name of virus: Rabies virus

Way of Transmission: through a bite from any infected animal or by intaking saliva of infected animals

Affected Organs: Nervous system

#8 Measles

Symptoms: Radish eruptions on body, Redish eyes, pain in eyes. Yellow urine, Eyes and skin become yellow.

Name of virus: Morbeli virus

Way of Transmission: through coughing and sneezing

Affected Organs: Whole body.

Disease Caused by fungus:


#1 Asthma

Symptoms: Shortness of breath, Chest tightness or pain, increasing difficulty breathing

Name of fungi: Aspergillus fumigatus

Affected Organs: Lungs

#2 Athlete’s Foot

Symptoms: cracking and peeling skin on your feet, most commonly between your toes and on your soles.

Name of fungi: Tenia Pades.

Affected Organs: feet, toes soles.

#3 Scabies

Symptoms: tiny blisters or bumps on skin, Itching.

Name of fungi: Acarus scabies

Affected Organs: Skin

#4 Baldness

Symptoms: Hair of the head start to fall.

Name of fungi: Taenia capitis

Affected Organs: Hair of the head

#5 Ringworm

Symptoms: Round red spot on skin

Name of fungi: Trycophyton Lerucosum

Affected Organs: Skin

This list provides a brief overview of some common human diseases caused by different microorganisms. Remember, proper hygiene, vaccination, and seeking medical attention when necessary are crucial for preventing and managing these illnesses effectively.

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