Causes of Infectious Diseases and How to Prevent Them


If you’ve ever been infected with a virus or bacteria, you know that less than one percent of the bacteria in the human body cause diseases. However, this doesn’t mean that all bacteria are harmful. On the contrary, some of them are beneficial to our health. Listed below are some of the most common causes of infectious diseases and how to prevent them. Hopefully, this information will help you better understand the nature of bacteria and how they can infect humans.

Pathogenic microorganisms

Infectious diseases are caused by pathogenic microorganisms, which are bacteria, viruses, protozoa, or fungi. These microorganisms can enter the body differently, including direct contact, droplets, airborne, and contaminated objects. These microorganisms can produce harmful bacteria or toxins that cause sickness or death. There are four main types of pathogenic microorganisms: bacteria, viruses, fungi, and protozoan parasites.


Infectious diseases are caused by microorganisms, most commonly viruses and bacteria. These pathogens can be transmitted directly from one person to another, making them contagious. However, some infections can be transmitted to humans only by biting an infected animal or insect. For example, Lyme disease is spread through the bite of an infected tick. Fortunately, there are many ways to prevent the spread of infectious diseases.

Yersinia pestis

Yersinia pestis is a bacterium found in soil, water, and other body fluids. The most common symptom of Y. pestis infection in humans is bubonic plague. A flea bite triggers this infectious disease, and the incubation period is two to eight days. Approximately 25 percent of people will develop a skin lesion at the site of the bite, which may be pustular, vesicular, or papular. The bacterium is also responsible for causing intense pain in regional lymph nodes and general weakness.


Several classes of bacteria cause infection. Strictly pathogenic bacteria overwhelm the immune system, and opportunistic pathogens can cause infection under certain circumstances. Bacterial infections often originate from an individual’s bacterial flora and are transmitted through contact with contaminated food or water. Bacteria can infect humans, animals, or vectors, multiply rapidly, and accumulate mutations in their DNA.


One of the most common human infections is caused by the bacteria known as Staphylococcus aureus, commonly referred to as staph. Infections caused by Staphylococcus aureus can range from superficial skin lesions to severe bloodstream infections, bones, or joint infections. These bacteria are highly contagious and are spread through contaminated hands.


There are more than 30 different species of staphylococci in the human body. The most common type causes infections, including skin and throat infections. Healthy adults carry Staphylococcus in their nose and skin, and approximately 25% of healthcare workers have it. Even minor wounds may harbor this bacteria, which can cause an infection. People with chronic conditions and weakened immune systems are especially susceptible.


Streptococcus pneumonia is the main bacterium that causes pneumococcal disease. This bacteria can invade several body parts, including the lungs, nose, middle ear, otitis media, and meningitis. Pneumococcal infections are usually caused by direct contact with the respiratory secretions of infected persons. They are generally not harmful to casual contacts but can cause serious illnesses when they enter the body.

Staphylococcus aureus

Staphylococcus aureus, a gram-positive coccus found in the skin and upper respiratory tracts, is a common cause of infections. Its surface proteins are catalase-positive, and its gene products produce nitrate reductase and other extracellular enzymes. Its pathogenic strains can induce disease by expressing their cell-surface protein and producing cytolytic toxins.


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