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Infection is when microorganisms, including bacteria, viruses, fungi, and parasites, enter the body and multiply, causing tissue damage and disease. Infection is one of the leading causes of illness and death worldwide, with millions of people affected each year.

Transmission: Infection can occur through various routes, including contact with contaminated objects or food, inhalation of airborne particles, and contact with infected individuals or animals. In some cases, an infection can also be transmitted through blood transfusions or organ transplants. The body’s immune system is designed to protect it from infection, but it can be overwhelmed by large numbers of invading microorganisms, allowing them to multiply and cause disease.

Infection can also occur when the body’s natural defenses are weakened by other conditions, such as malnutrition, immunodeficiency, or certain medications. The severity of infection depends on the type of microorganism involved and the damage it can cause. Some infections, such as the common cold, are mild and cause only minor symptoms. Others, such as pneumonia, can be life-threatening.

Treatment for infection depends on the type of microorganism involved and the severity of the infection. Treatment options include antibiotics, antivirals, antifungals, and antiparasitic drugs. In some cases, the infection may be prevented with vaccinations or by taking measures to reduce exposure to infectious agents, such as avoiding contact with people who are ill or washing hands frequently.

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  • National Institute of Allergy and Infectious Diseases. (2018). What is an Infection? Retrieved from 
  • Centers for Disease Control and Prevention. (2018). Infections. Retrieved from 
  • World Health Organization. (2018). Infectious diseases. Retrieved from