Latency in Infection

What is latency in infections?

Latency is a type of infection where the pathogen remains inside the host without causing obvious disease symptoms.

Why do pathogens enter latency?

Pathogens enter latency to avoid immune detection and survive long term inside the host.

What are the hallmarks of bacterial latency?

Bacterial latency includes reduced metabolic activity, stopped division, reduced gene expression, and tolerance to antibiotics.

What occurs during viral latency?

During viral latency, the viral genome remains inside host cells, no active virion production occurs, and host cells survive.

How do viruses avoid immune detection during latency?

Viruses avoid detection by not producing viral proteins needed for replication, resulting in reduced or absent antigens.

What is the significance of LAT (Latency Associated Transcript)?

LAT helps maintain latency by being processed into a 2 kb intron that accumulates at high levels inside neurons.

What triggers the reactivation of herpes viruses?

Reactivation can occur due to stress, trauma, environmental factors, or weakened immunity.

What defines latent tuberculosis infection (LTBI)?

LTBI features a positive TB test, normal chest X-ray, negative sputum for acid-fast bacilli, and absence of symptoms.

What factors contribute to the dormancy of Mycobacterium tuberculosis?

Dormancy is enforced by strong immune pressure and conditions such as low oxygen and nutrients inside granulomas.

What are resuscitation factors in TB?

Tuberculosis expresses resuscitation-promoting factors (Rpfs) which may help dormant bacteria resume growth.

What's the difference between viral and bacterial latency?

Viral latency involves persistence of the viral genome without producing infectious particles; bacterial latency involves surviving in a metabolically inactive state.

What are the key viruses involved in latency?

Important human herpes viruses include HSV-1, HSV-2, and Varicella zoster virus (VZV).

How does mTORC1 factor into viral latency?

mTORC1 may suppress the lytic cycle by sequestering host factors in the cytoplasm.

What is the role of microRNAs in HSV latency?

HSV microRNAs repress transcription of lytic genes, preventing production of proteins needed for active infection.

What are the main features of active infection by herpes simplex virus?

Active infection involves virus infecting epithelial cells, replicating its genome, producing proteins, and destroying host cells.

How do latent bacterial infections exhibit antibiotic tolerance?

Latent bacteria are metabolically inactive and not dividing, making antibiotics targeting active processes less effective.