Introduction
With the onset of COVID-19 (coronavirus of 2019) a few years back, fear of infectious disease has increased in public. Although they have different meanings, infectious and contagious diseases are used interchangeably. All communicable diseases can be classified as infectious, but not all infectious diseases are communicable. The communicable diseases have a high potential for spreading and causing pandemics. In public health emergencies, the diseases must be appropriately classified as infectious or contagious to formulate containment strategies. Differences between infectious and contagious diseases are discussed within the article.
What Is an Infectious Disease?
Infectious disease develops when agents such as bacteria, fungi, parasites, or viruses invade the body. Bacteria or fungi divide and grow new cells at an exponential rate. The virus that enters the body takes over the host’s control centers. For example, tetanus is an infectious disease caused by bacteria that live in the dust and enters the human body through cuts, puncture, or scrapes. Other examples are chickenpox, cholera, common cold, COVID-19, Ebola, flu, hepatitis A and B, Lyme disease, and HIV (Human Immunodeficiency Virus) or AIDS (Acquired Immunodeficiency Virus).
Humans develop infection when the invading organism attacks the body and causes the immune system to produce white blood cells and antibodies to defend themselves. In some cases, infectious diseases can be life-threatening. Disease prevention is by consuming a healthy diet, regularly exercising, and keeping hands clean by washing.
Notifiable diseases are a subset of infectious diseases brought to the attention of health authorities. The notifiable diseases are bloodborne, gastrointestinal, sexually transmitted, vaccine-preventable, vector-borne, and zoonosis. These diseases require continuous surveillance to prevent community spread. Non-notifiable infectious diseases do not require regular monitoring. Examples include upper and lower respiratory tract infections, trachoma, and viral hepatitis.
What Is a Communicable Disease?
The infectious agents or viruses spread the disease from one person to the other person or from animals to humans. The illnesses caused by infectious diseases are acute and short-term, and the effect of the condition is external. Communicable diseases can cause small, isolated outbreaks or pandemics.
For example, flu is an infectious disease that spreads among individuals through sexual activity, respiratory droplets, blood transfer, or vertical transmission. If they are not immune, every person with the flu infects one or more other people.
What Are the Modes of Transmission of Diseases?
The mechanisms through which disease spreads are:
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Person to Person: The disease-causing pathogen can be transmitted between individuals through contaminated respiratory secretions or blood, sexual activity, mother-to-child, birth, or breastfeeding. Sneezing and coughing can spread the disease even though the affected individual is asymptomatic. For example, measles can spread four days before the rash develops.
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Airborne Transmission: Some infectious agents are suspended in the air and infect individuals who inhale them. For example, tuberculosis is an airborne infectious disease.
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Vector: Some diseases spread from one person to another through a vector. For example, mosquitoes are the most common vector, affecting millions yearly. The mosquitoes carry malaria parasites after biting infected individuals and pass them to others by biting. The vector alone cannot spread the disease without an infectious agent.
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Fomites: Some infectious agents survive on hard surfaces. As healthy individual comes into contact with these infected surfaces, they become susceptible to developing the illness. Therefore, washing hands is essential to prevent such disease. For example, when an individual infected with a cold or flu rubs their nose and touches other surfaces, they contaminate them with the virus.
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Fecal-Oral and Foodborne: Some germs can spread through contamination with fecal matter. For example, a surface can be contaminated by an individual who has not washed hands after using the bathroom. When others touch the surface and put their hands in their mouth, they can become infected. Spoiled food contains toxins, bacteria, or parasites. When this food is consumed, it causes food poisoning. Bacterias contaminating spoiled food and causing human disease are E. coli, salmonella, botulinum, staphylococcus aureus, cholera, and listeria. Food poisoning is a non-communicable infectious disease.
- Vertical Transmission: Some diseases can be transmitted from the infected mother to the child during pregnancy, childbirth, or breastfeeding. An example is HIV or AIDS.
What Are the Fundamental Differences Between Infectious and Communicable Diseases?
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Disease Transmission: Infectious diseases are caused by bacteria, fungi, viruses, or parasites, and the disease may or may not be transmitted to others. Infectious diseases include a broad group of disorders with no transmission or mild transmission potential. Viral infections or other infectious agents are the source of communicable diseases, which can spread from person to person or from animal to human. The communicable disease includes disease with significant transmission potential.
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Management: Infectious diseases are managed by analyzing the type of disease-causing pathogen and formulating prevention and treatment strategies. The communicable disease can cause widespread infections. Therefore, emphasis should be on interrupting transmission chains, public health intervention, and public awareness.
How Are Infectious and Communicable Diseases Prevented?
The burden of infectious diseases in the developed world is relatively small. However, some people develop infectious diseases like the common cold or stomach bug during their lifetime. Communicable disease has affected everyone worldwide, with the recent being COVID-19. Some diseases can cause severe illness, outbreaks, or even deaths. Some infectious pathogens have recently become antibiotic-resistant, lengthening and complicating the disease course.
The burden of infectious disease has declined with improved sanitation, prevention, and disease treatment. Clean hands regularly with soap and water for 20 seconds, or use alcohol sanitizers to help prevent diseases. Infected individuals must cover their mouth or nose with tissue or elbow while sneezing or coughing. Vaccination and immunization are also effective strategies against infectious and communicable disorders. Food must be cooked to the appropriate temperature because eating undercooked meat might spread certain infections. Avoid contact with infected individuals as there is a risk of spreading infection. Utilizing condoms can reduce the chances of contracting HIV and other STDs (sexually transmitted diseases).
Bacterial infections need antibiotic therapy. However, viral infections do not have treatment, and the disease is left to run its course. Supportive care is essential for individuals with viral infectious diseases.
Conclusion
Although infectious and communicable diseases are terms used interchangeably, they differ in the context of public health needs. Infectious diseases include pathogens responsible for causing illness, whereas communicable diseases spread due to infectious agents.
