10 Important diseases caused by virus and fungi in humans

Virus and fungi are a different set of pathogens which cause diseases.

But unlike others, the diseases caused by them are obstinate and can pose a severe danger if the immune system is weak.

Viral fevers, jaundice, and colds are common diseases caused by the virus.

While fungi cause systemic (in the blood) and superficial skin infections.

Diseases caused by virus and fungus in humans

The diseases caused by viruses and fungi are quite different in nature and severity. They affect both animals and plants.

They are mostly caused by transmission from one person to another by physical contact, airborne transmission, or other forms of contamination.

First, we will see diseases of viruses and then of fungi.

Diseases by the virus in humans

The virus is a non-living intracellular parasite without any metabolic machinery of its own. These infective agents have essentially a nucleic acid as the genetic material enclosed in a protein capsule.

This genetic material can be either DNA or RNA and some viruses have lipoprotein coats too on the capsid. See the structure of the virus.

They act as parasites for their multiplication by taking over the protein machinery of the host cell.

But once out of the host body, it is difficult for it to survive in the heat and humid conditions. dies. However, it can infect from one person to another and can stay inside for long as long as the immune system destroys it completely.

They can infect almost all the living cells i.e. plant cells, animal cells, bacteria, algae, and even yeast cells.

The viral diseases are so devastating that many towns lost a huge population due to deaths. They have traveled all over the world just by human infections.

Unlike bacteria and other pathogens, these viruses show sudden outbursts leading to many deaths. So they are to keep under control by the use of vaccines.

List of viral diseases in humans include

1. Skin diseases: Smallpox, chickenpox.  These cause pustular skin eruptions. They spread by air from person to person by sneezing etc. The symptoms can be severe and if untreated can cause death. Warts are skin eruptions caused by papillomavirus.

measles virus with glycoprotein tubercles
Measles virus particle with glycoprotein tubercles that help to fix to human cells


2. Gums and buccal cavity: Mumps causes swelling of the throat (parathyroid gland).

3. Brain: Encephalitis, meningitis can cause brain damage and death.

4. Eye: conjunctivitis.

5. Ear: labyrinthitis.

6. Respiratory tract: Flu, Colds, etc.

7. Blood: Measles, AIDS, Dengue fever

8. Bone: Polio.

9. Liver: Hepatitis-B, C, D & E, yellow fever.

10. Heart: Myocarditis.

In plants: The viruses of plants are quite different from animals. They have different genetic material. They can cause severe infection to plants in agriculture and farming.

Leaf mosaic: In tobacco, tomato, beans, chili, brinjal, etc.

Malformation of mango, leaf roll and curl in potato and papaya respectively.

They are treatable using anti-viral drugs to a certain extent.

Diseases caused by fungi

Unlike a virus, the fungi have cells and are multi-cellular microscopic organisms. They can survive as a parasite in the body leading to disease. 

Most of the fungi damage foods, while some fungi like mushrooms are even consumed as foods.

But fungus can also disease by infection. Fungi are spread from external sources to internal. That is from the skin to blood and so on. The transmission from humans to humans is very low. The infection by fungus is mostly two types like

External infection: This is mostly seen on the skin, nails, etc. These are treatable and not so dangerous. They are sometimes influenced by seasonal changes and the food habits of the patient.

1. Skin: They mostly cause ringworm like teniapedis on foot, athlete’s foot, (on the skin, nails, foot, hands, groin, etc.)

2. Mucous: Inflammation of mucous membranes like mouth, tongue, uterus, and other body orifices.

3. Ear: causes otomycosis an infection in the ear by Aspergillus.

4. Eye: Corneal infection called fungal keratitis.

Internal infection. These infections are systematic (i.e. in the blood), they are dangerous and life-threatening.  They can directly produce disease by primary infection. 

Liver: Histoplasmosis an infection caused by the fungus Histoplasma capsulatum.

Lungs: Cocidiomycosis which causes pneumonia. It is an infection from external soil to humans by air.

Blood: Candidiasis. It can affect other important organs like the heart, brain.

Kidney: This type of infection occurs in kidney transplant patients.

But in many cases, the fungal infections are due to secondary infection as a side effect of antibiotic therapy.

In normal conditions, the fungus growth is kept under control by vegetative bacteria.

But when antibiotics are used in disease conditions, the normal friendly bacteria are also killed.

This leads to an uncontrolled invasion of fungi in the body. This is called a secondary infection. An individual with cancer, diabetes, etc. is also more susceptible to fungal infections.

Ex: Systemic candidiasis, Aspergillosis, Penicilliosis, etc.

Even yeast infections are also prominent nowadays. Unlike bacteria, fungal cell organelles are not quite different from humans. So, it is quite hard to target fungi cells without hurting normal human cells. Thus, using anti-fungal drugs can cause side effects to humans also.

Disease causedFungi responsible
AspergillosisAspergillus fumigatus, A.flavus, A. Niger
BlastomycosisBlastomyces dermatitidis
CandidiasisCandida albicans
CoccidioidomycosisCoccidioides immitis
CyptococcossiCryptococcus neofromans
HistoplasmosisHistoplasma capslatum
MycetomaMadurella mycetomatis
Rhiosporidiosis Rhinosporidium seeberi.
Suerficial mycosisTrichophyton, Microsporum, epidemophyton.

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