Difference Between Infection and Disease


Main Difference

The main difference between Infection and Disease is that Infection is an attack of microorganisms inside the body, and causing harm to the body, whereas Disease is weakening of the body’s immune system after infection.

Infection vs. Disease

Infection is the entry of microorganisms into the body that cause weakening of the immune system. In contrast, the disease is described as the symptoms appearing after the weakening of the immune system. Infection can be defined as a body’s immune response as a counterattack to pathogens. In contrast, the disease occurs when the immune system gets deteriorated, and pathogens start dominating and harming the cells of the body.


Different kinds of infection show different kinds of symptoms, i.e., headache, stomach ache, chills, sweating, body ache, loss of hunger, and weight loss, etc. On the other hand, the disease appears with the symptoms of pain, fever, aches, etc. that refer to the dwindling of immune functions, depending on the kind of pathogen that attacked the body and part of the body being attacked.

Infection can be treated after accurately diagnosing the specific type of infection. On the other hand, the disease is treated according to its type. An infection can be either clinically visible means causing symptoms or subclinical means not causing symptoms. On the flip side, a disease is accompanied by symptoms at different stages of diseases.


In response to infection, the immune system is stimulated and starts the action, while disease occurs when the immune system fails to deteriorate the pathogens. An infection occurs when pathogenic microbes begin to replicate. In contrast, the disease arises when the cells in the body are impaired.

Comparison Chart

Attack and entry of pathogenic microorganisms in a body that stimulates the immune system is called infection.A condition of the body caused by an extreme stimulus, occurring with impaired homeostasis and reduced quality of life processes, is called disease.
Viruses, bacteria, macroparasites (worms, ticks), fungi, etcInjury, infection, hereditary factors, environmental factors, lifestyle, etc
Fatigue, loss of appetite, weight loss, temperature, chills, night sweats, pain, runny nose, abdominal pain, vomiting, etching, and skin rashes, etc. depending on the type on infectionNausea, vomiting, swelling, pain, breathing problems, diarrhea, bleeding symptoms, etc. depending on the type of disease
Contagious (can be transferred from infected to a healthy person)Can be contagious or non – contagious
Its treatments are antibiotics, anti-inflammatory drugs, proper cleaning and sterilization of wounds, etc.Its treatments are medicines, lifestyle changes, a healthy diet, surgery, etc.
Tuberculosis, severe pneumonia, smallpox, syphilis, AIDS, measles, mumps, polio, influenza, gonorrhea, etcHigh blood pressure, heart disease, lung disease, autoimmune disease, stomach disease, etc

What is Infection?

Infection is a contagious process of transmission that can be transferred from an infected person to a healthy person. Infection is the entry of disease-causing microorganisms like bacteria, fungi, or parasites that start replicating inside the body and harm the immune system.

An infection caused by pathogenic microorganisms can either be clinically expressed, means symptoms showing, or subclinical means symptoms not expressed. The ability of microorganisms to cause an infection either clinically or subclinically is called infectiousness.

The spectrum or range in which a specific specie of microorganisms can cause infection is called the infection spectrum. The infection spectrum of some pathogens is very diverse, i.e., rabies virus can result in infection in all mammals. Some microorganisms have a narrow infection spectrum, i.e., syphilis, gonorrhea, and AIDS can cause infection in humans only. Symptoms of infection that affect the whole body are fatigue, loss of appetite, weight loss, temperature, sweating, and pain. Symptoms of infection that affect specific parts of the body are rashes related to skin, cough, stuffy nose, runny nose, suffocation related to respiratory organs, and vomiting, abdominal pain, stomach problems related to the digestive tract.

Treatment of infection is done by diagnosing either the cause of infection is a virus, bacteria, or fungi. According to the pathogen, infection is treated, i.e., antibiotic is given for infection against bacterial infections like cholera, diphtheria, dysentery, tuberculosis, and typhoid, etc.

Antibiotics are not effective against viruses, and their use increases the resistance against antibiotics. Therefore, antiviral medications are used against viruses like coronavirus, meningitis, herpes virus, hepatitis, gastroenteritis, cowpox, COVID-19, etc.

What is Disease?

The disease is defined as an unhealthy or ill condition of life. Deviation from the normal life of organisms accompanied by structural and functional changes is called disease. The diminished homeostasis and reduced quality and efficiency of life processes are termed as a disease.

A disease can either be contagious (can be transferred from infected to a healthy person), or non-contagious (cannot be transferred from infected to a healthy person). A disease can be caused by many factors, including injury, sedentary lifestyle, unhealthy diet, infection, hereditary factors, and environmental factors, etc.


  • Latent Stage: The time duration from the entry of pathogenic microorganisms to the appearance of the first sign is called the latent stage. The disease remains hidden.
  • Prodromal Stage: The time duration from the appearance of the first clinical sign to the formation of a complex collection of all the symptoms ultimately is called the prodromal stage. The defensive mechanism of the body is deteriorated.
  • Thoroughly Dominant Stage: The stage in which the disease is dominant with its all symptoms and vigor is called the thoroughly dominant stage.
  • Ending Stage: The last stage in which all the possibilities of recovery are lost, and disease is leading to death is called the ending stage.


  • Subjective: Symptoms that show how the body feels.
  • Objective: Observable symptoms.


Treatment of disease can be done by proper medication, adopting a healthy lifestyle, a healthy diet, and maintaining the best quality of life. Some diseases require surgery for their treatment.

Key Differences

  1. Infection is a contagious disease, which spreads from an infected person to a healthy person. In contrast, the disease can be either contagious or non-contagious.
  2. Infection occurs when pathogenic microorganisms enter the body and stimulate an immune response against their mode of action. In contrast, the disease occurs when excessive or unusual stimuli cause deviation in normal quality of life.
  3. An infection occurs when pathogens attack the immune system of the body and spread themselves by replication in the host body. On the flip side, the disease occurs when the immune system is weakened, and cells of the body are damaged.
  4. Viruses, bacteria, fungi, and macroparasites are the pathogens that cause infection. On the other hand, injuries, infections, lifestyle, hereditary, and environmental factors are involved in causing disease.
  5. Painful and swollen wounds with pus, fever, itching, runny nose, cough, muscle and joint point pain, fast heartbeat, and dizziness are a few symptoms of infection. On the flip side, nausea, abdominal pain, swelling, breathing problems, and bleeding symptoms are symptoms of a disease.
  6. Infections can be treated by antibiotics against bacteria, anti-inflammatory drugs against inflammation-causing substances, anti-viral drugs against viruses, and wound cleaning, etc. On the other hand, diseases can be treated by medicines, healthy lifestyle, healthy diet, and surgery, etc.


The entry of pathogenic microorganisms and their replication inside a body that weakens the immune system is called an infection, whereas deviation from normal quality of life is called disease.

Janet White

Janet White is a writer and blogger for Difference Wiki since 2015. She has a master's degree in science and medical journalism from Boston University. Apart from work, she enjoys exercising, reading, and spending time with her friends and family. Connect with her on Twitter @Janet__White