Infectious Diseases: Viruses Overview

A tiny infectious agent that's made up of genetic material (RNA or DNA) wrapped in a protein coat.

The virus's genetic material (RNA or DNA) that contains the instructions for making more viruses.

The outer layer of some viruses, made from the host cell's membrane.

The process by which a virus enters a host cell, replicates, and then releases new viruses.

The process by which a virus is released from a host cell without destroying the cell.

The process by which a virus is released from a host cell by destroying the cell.

The molecule on the surface of a host cell that a virus binds to in order to enter the cell.

A virus cannot replicate on its own, it needs to infect a host cell.

The process by which a virus leaves a host cell without killing it.

A stage in the HIV lifecycle where the viral proteins are cut into smaller, functional pieces by a protease enzyme.

A type of immune cell that plays a crucial role in fighting HIV.

A substance that helps HIV escape the immune system by masking the virus from antibodies.

A state where the immune system is weakened, leading to vulnerability to opportunistic infections.

An HIV therapy that combines multiple drugs to target different stages of the virus's life cycle.

The point at which a person with HIV develops a weakened immune system and is susceptible to opportunistic infections.

A group of infections that commonly occur in people with weakened immune systems, especially those with AIDS.

A type of immune response to Flaviviruses, such as Dengue, where pre-existing antibodies bind to the virus, but instead of neutralizing it, they enhance its entry into host cells, potentially leading to a more severe infection.

The process of a virus entering a host cell by fusing with the cell's membrane.

A non-coding RNA produced from the 3' untranslated region (UTR) of Flavivirus genomic RNA. It is thought to play a role in inhibiting the host's immune response.

The polyprotein encoded by Flaviviruses is cleaved into individual proteins by both viral and host proteases. This process is essential for the maturation and function of viral proteins.

A family of viruses containing a positive-sense single-stranded RNA genome, typically enveloped, and with a characteristic spiky surface. They include viruses such as Dengue, Zika, and Yellow Fever.

A receptor expressed on dendritic cells, which can be used by Flaviviruses to enter these cells.

A protein on the viral envelope that undergoes conformational changes in acidic environments, enabling the virus to fuse with the cell's membrane.

The viral genome, a single-stranded RNA molecule of positive polarity, that serves as a template for both translation and replication.

The process by which a virus is eliminated from the body by the immune system, preventing future infections.

Type of immune response that is rapid and specific to re-infection, it relies on prior exposure.

Type of immune response that's always ready to fight, even without prior exposure.

A group of proteins crucial for fighting viruses, acting as messengers that initiate antiviral responses.

A type of interferon produced by all cells and crucial for activating antiviral responses.

A family of genes that are switched on by interferons, helping the cell combat viral infections.

A protein that blocks translation initiation, inhibiting viral protein synthesis by recognizing double-stranded RNA (dsRNA).

An enzyme that degrades viral RNA, effectively shutting down viral replication.

A community of bacteria that live together in a slime-like matrix. They stick to surfaces and can be found in various environments like your teeth!

Biofilms can resist physical force, antibiotics, and even phagocytosis by immune cells.

Bacteria inside a biofilm communicate with each other, share nutrients, and even exchange genetic information.

It's a type of bacterial infection that affects the lungs and can spread throughout the body. It's caused by a slow-growing bacterium with a unique, waxy cell wall.

Tuberculosis spreads through the air when an infected person coughs or sneezes. It's a common infection, but most people who get infected don't get sick.

If a person's immune system is weakened, they are at a higher risk of developing active TB.

The immune system uses both physical barriers and cells to fight off tuberculosis infection.

Interferon gamma, a crucial immune molecule, activates macrophages, which are immune cells that engulf and kill bacteria. A defect in this molecule can make you highly susceptible to Mycobacterial infections.

Alveolar macrophages are the primary target cells for Mycobacterium tuberculosis infection. These are specialized immune cells located in the alveoli of the lungs, where they engulf bacteria as part of the innate immune response.

M. tuberculosis can survive and replicate within alveolar macrophages, creating a permissive environment that allows it to evade the host's immune system.

To avoid detection by the immune system, M. tuberculosis has mechanisms to inhibit the fusion of phagosomes with lysosomes, the digestive organelles of the macrophage. This allows the bacteria to survive inside these compartments.

M. tuberculosis can obtain essential nutrients, such as iron and fatty acids, from within the macrophage, which it uses to grow and persist. The macrophage's lipid accumulation can further fuel the bacteria's metabolism.

M. tuberculosis can suppress the inflammatory response under normal conditions, preventing excessive lung damage. This anti-inflammatory environment benefits the bacteria by allowing it to evade host defenses.

M. tuberculosis can detoxify reactive oxygen and nitrogen species produced by alveolar macrophages, which are normally bactericidal. This detoxification allows the bacteria to survive and multiply within the macrophage.

M. tuberculosis can survive in epithelial cells but finds the conditions less favorable for replication compared to alveolar macrophages.

Early in infection, alveolar macrophages exhibit anti-inflammatory characteristics to prevent excessive lung damage. This anti-inflammatory environment is advantageous for M. tuberculosis, allowing it to replicate intracellularly.