Retroviruses have a single-stranded RNA genome that undergoes a special form of replication. Once the retrovirus has entered the host cell, an enzyme called reverse transcriptase synthesizes double-stranded DNA from the retroviral RNA genome. This DNA copy of the genome is then integrated into the host’s genome inside the nucleus via an enzyme called integrase. Consequently, the retroviral genome is transcribed into RNA whenever the host’s genome is transcribed, allowing the...

Sexually transmitted infections (STIs) are diseases transmitted primarily through unsafe sexual interactions. Bacteria, viruses, or parasites cause them and can result in severe health complications if untreated.ChlamydiaThe bacterium Chlamydia trachomatis is responsible for the disease Chlamydia, the most common STI in the United States. This peculiar pathogen requires human cells to reproduce, residing intracellularly. The initial infection often goes unnoticed because it typically does not...

Immunodeficiency disorders are conditions in which the immune system's ability to fight infectious disease and cancer is compromised or entirely absent. The immune system comprises a complex network of cells, tissues, and organs that work together to protect the body from potentially harmful invaders. When this system is deficient or not functioning properly, it leaves the body susceptible to infections, diseases, or other complications.
There are three main causes of immunodeficiency...

Tuberculosis, often called TB, is a contagious illness primarily caused by Mycobacterium tuberculosis. It mainly affects the lung parenchyma but can also impact other body parts.
Causative Organism
The primary infectious agent causing tuberculosis is Mycobacterium tuberculosis, a slow-growing, acid-fast, aerobic rod that exhibits sensitivity to heat and ultraviolet light. Instances of Mycobacterium bovis and Mycobacterium avium contributing to the development of TB infection are rare.
Mode of...

Huntington disease or HD is a progressive, fatal neurodegenerative disorder inherited in an autosomal dominant pattern.PathophysiologyIt is caused by expansion of the CAG trinucleotide repeat in the HTT gene on chromosome 4 (4p16.3), producing an abnormal huntingtin protein with an expanded polyglutamine tract. This misfolded protein disrupts cellular function, leading to neuronal death. Normal alleles have ≤26 repeats, 27–35 are intermediate (risk of expansion), 36–39 show...

Infective endocarditis management involves a multifaceted approach encompassing infection prevention, lifestyle modifications, pharmacological therapy, and surgical management.Infection Prevention:Hand Hygiene: Thorough handwashing is crucial to prevent the spread of infection. Hand hygiene should be performed regularly, especially before and after using the restroom.Oral Hygiene: Good oral hygiene is essential. It includes brushing teeth immediately after waking up and before bed, flossing...