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What causes infections or infectious diseases?

Infections or infectious diseases occur when harmful viruses, bacteria or other microorganisms (such as fungi. parasites and prions) enter the body. They multiply and in some people, cause disease.  

How are they passed on?

Infection can be transmitted through direct or indirect contact, or vectors. Direct contact includes through body waste products such as mucus or pus from open sores, ulcers, or wounds. Indirect contact could occur through contact with objects such as bed linens, bedpans, or drinking glasses. Vectors are flies, mosquitoes, or other insects capable of spreading the infectious agent.

How are infections diagnosed?

Many infections are diagnosed clinically, but sometimes the cause of the infection is identified by laboratory tests on  samples taken from people. 

What types of infectious diseases are there?

Infectious diseases can be viral, bacterial, parasitic or fungal infections. A few examples of viral infections include Flu (influenza),  COVID-19 and measles.  A few examples of bacterial infections include strep throat, tuberculosis, UTIs and salmonella. Examples of fungal infections include Athlete’s foot, vaginal yeast infection and thrush.

Why do we need research into infection and infectious disease?

Research addresses infection prevention and control, and treatment options. It improves our understanding of how to manage infections in hospitals. Continuing research into will enable us to better understand, prevent, control and manage infections. 

You can learn more about some of the findings from NIHR-funded research below.