10 Differences Between virus and viroids

Differences Between Virus and Viroids


Viruses and viroids are two types of infectious agents that affect living organisms. While both are microscopic, they have distinct characteristics and effects. This article explores the differences between viruses and viroids, including their definitions, examples, uses, and key contrasting aspects.

What is/are Virus?

A virus is a small infectious agent that replicates inside the cells of living organisms. It consists of genetic material (DNA or RNA) enclosed in a protein coat called a capsid. Viruses can infect all forms of life, including animals, plants, and microorganisms.

Examples of Viruses

Some well-known examples of viruses include:

  • Influenza virus
  • HIV (Human Immunodeficiency Virus)
  • Herpes simplex virus
  • Poliovirus
  • Coronavirus

Uses of Viruses

Viruses have both harmful and beneficial uses:

  • Harmful Uses: Viruses can cause diseases in humans, animals, and plants, leading to illness and sometimes death.
  • Beneficial Uses: Viruses are utilized in various fields, such as gene therapy, vaccine development, and biological research.

What is/are Viroids?

Viroids are small infectious agents that are composed solely of single-stranded RNA molecules. Unlike viruses, they lack a protein coat and do not encode any proteins. Viroids are known to cause diseases only in plants, specifically affecting the growth and development of the infected plant.

Examples of Viroids

Some examples of viroids include:

  • Potato spindle tuber viroid
  • Chrysanthemum stunt viroid
  • Peach latent mosaic viroid
  • Coconut cadang-cadang viroid
  • Apple scar skin viroid

Uses of Viroids

Viroids do not have any known beneficial uses and are primarily studied to understand how they impact plant health and develop strategies for viroid disease prevention and control.

Differences Table

Difference Area Virus Viroids
Viral Structure Composed of genetic material (DNA or RNA) and a protein coat. Composed of single-stranded RNA molecules without a protein coat.
Host Range Infects all forms of life, including animals, plants, and microorganisms. Only infects plants.
Replication Requires a host cell to replicate. Can replicate autonomously without a host cell.
Disease Impact Can cause diseases in humans, animals, and plants. Only known to cause diseases in plants.
Protein Coding Viruses encode proteins. Viroids do not encode any proteins.
Physical Size Generally larger in size. Smaller in size compared to viruses.
Transmission Can be transmitted through various means, including direct contact, air, or vectors such as insects. Primarily transmitted through plant sap and seeds.
Signs and Symptoms Symptoms can vary depending on the virus but frequently include fever, cough, rash, and more. Symptoms in plants include stunting, discoloration, deformities, and reduced yield.
Target Cells Viruses infect specific types of cells within host organisms. Viroids infect various plant tissues.
Life Cycle Complex life cycle involving attachment, entry, replication, assembly, and release. Simple life cycle primarily involving autonomous replication within host plant cells.


In conclusion, viruses and viroids are both infectious agents, but they differ in various aspects. Viruses are larger, infect a wide range of hosts, can cause diseases in animals, plants, and microorganisms, and have beneficial uses in research and medical applications. In contrast, viroids are smaller, infect only plants, do not encode any proteins, and are primarily studied for plant disease prevention. Understanding their differences allows better comprehension and management of the associated diseases.

People Also Ask

  • Q: Can viroids infect humans?
  • A: No, viroids only infect plants and have not been found to infect humans or animals.

  • Q: Can viruses be beneficial?
  • A: Yes, viruses have beneficial uses such as in gene therapy and vaccine development.

  • Q: Are viroids smaller than viruses?
  • A: Yes, viroids are smaller in size compared to viruses.

  • Q: How do viruses replicate?
  • A: Viruses require a host cell to replicate their genetic material and produce new virus particles.

  • Q: What are the symptoms of viroid infection in plants?
  • A: Viroid infection in plants can result in stunting, discoloration, deformities, and reduced yield.

Leave a Comment

content of this page is protected

Scroll to Top