Diseases: UPSC Previous Year Questions (Science and Technology)

Explanation

Antimicrobial Resistance (AMR) is the ability of microorganisms like bacteria, viruses, fungi, and parasites to resist the effects of antimicrobial drugs, making infections harder to treat. When microorganisms such as bacteria develop resistance to multiple drugs, it is specifically termed Multidrug Resistance (MDR), posing a serious challenge to effective treatment.

Statement 1 is incorrect: Multi-drug resistance is primarily a result of microbial adaptation, excessive antibiotic use, and misuse rather than human genetic predisposition. Genetic predisposition is a genetic trait that, in response to environmental factors, may influence the potential phenotypic development of an individual organism within a species or community. Antibiotic resistance is not related to the genetic tendency of a small minority of persons in a society.

Statement 2 is correct: Misuse of antibiotics, such as incorrect dosing, premature discontinuation of prescribed antibiotics, or self-medication, allows bacteria to survive and develop resistance. WHO mentions inappropriate use of antibiotics as a major driver of antimicrobial resistance.

Statement 3 is correct: The extensive use of antibiotics in animals, especially for growth promotion and disease prevention, contributes to the development of resistant bacteria. These resistant strains can transfer to humans through the food chain or direct contact.

Statement 4 is incorrect: While having multiple chronic diseases (like diabetes, hypertension, or cancer) may lead to prolonged or frequent use of antibiotics due to recurrent infections, it is not a direct cause of multi-drug resistance (MDR) in microbial pathogens.

Explanation

The Cas9 protein, often referred to as "molecular scissors," is an enzyme utilized in targeted gene editing. It originates from the CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) system, which serves as an adaptive immune mechanism in bacteria. Guided by a specific RNA sequence, Cas9 binds to a complementary DNA sequence and introduces a double-stranded break. This break facilitates targeted modifications, such as gene insertion, deletion, or correction. Cas9 has revolutionized genetic research and therapy by enabling precise edits in the genomes of various organisms, including plants, animals, and humans. This technology holds potential for treating genetic disorders, developing disease-resistant crops, and advancing gene therapy.

Explanation

Hepatitis is an inflammation of the liver, often caused by viral infections (hepatitis A, B, C, D, E). Its symptoms include fatigue, jaundice, and abdominal pain. Statement (a) is correct: Both Hepatitis B virus (HBV) and HIV are transmitted through contact with infected blood, semen, or other body fluids. Statement (b) is incorrect: A vaccine is available for Hepatitis B, which is effective in preventing HBV infection. However there is currently no vaccine for Hepatitis C. Statement (c) is correct: The global prevalence of HBV and HCV infections is significantly higher than that of HIV. Statement (d) is correct: Both HBV and HCV can lead to chronic infections where individuals remain asymptomatic for years, often until significant liver damage has occurred.