Communicable And Infectious Diseases

* **Chikungunya** is a mosquito-borne viral disease that cannot be spread through tattooing. * **Hepatitis B** is a liver infection that can lead to liver failure and cancer. It's spread through contact with the blood, open sores, or body fluids of an infected person. * **HIV** is a virus that destroys the white blood cells responsible for fighting infections. It can result in AIDS, the final stage of infection. It spreads mainly through unprotected sex, sharing drug needles, or contact with infected blood.

**Statement 1 is correct:** Viruses do not have metabolic machinery of their own. They lack enzymes needed for ATP generation and therefore must depend entirely on a host cell. **Statement 2 is incorrect:** Viruses cannot be grown on artificial or synthetic media. They need living host cells (bacteria, plants, animals, or cell cultures) to replicate. **Statement 3 is incorrect:** Transmission can occur through: - Physical contact, respiratory droplets - Contaminated water/food - Airborne routes - Fomites (inanimate objects) - Biological vectors (mosquitoes, ticks, etc.) Hence, vectors are not the only mode of transmission.

Hibernation is a state of decreased physiological activity and lowered body temperature that certain animals, such as bats and bears, undergo during the winter months to conserve energy and survive periods of limited food availability. **Statement 1 is correct:** Bats, especially those living in temperate regions, often enter a state of hibernation during the colder months when their food sources (insects) are scarce. **Statement 2 is correct:** Bears, including the brown bear, black bear, and polar bear, are well-known hibernators. **Statement 3 is correct:** Many rodent species, including groundhogs and chipmunks, are true hibernators. Thus, all three statements are correct.

**Statement 1 is incorrect:** The Government introduced the Pentavalent vaccine, which also fights against Diphtheria. This implies that Diphtheria is still prevalent. **Statement 2 is incorrect:** Chickenpox is still widespread among the population. **Statement 3 is correct:** Smallpox has been eradicated from India. India declared itself free of smallpox in 1979.

Mites, scorpions, and spiders are all classified within the class Arachnida. Crabs, although arthropods like the others belong to the class Crustacea. Therefore, the crab is the odd one out due to its different taxonomic classification.

Guinea, Sierra Leone, and Liberia were in the news for the outbreak of the Ebola virus. The most widespread outbreak of the Ebola virus disease began in 2013 and continued until 2016, causing major loss of life and socio-economic disruption in the West African region, mainly in the countries of Guinea, Liberia, and Sierra Leone. The first cases were recorded in Guinea in December 2013. Later, the disease spread to neighboring Liberia and Sierra Leone. Therefore, option B is the correct answer.

Influenza (H1N1) virus is a subtype of influenza A virus that was the most common cause of human influenza (flu) in 2009 and is associated with the 1918 outbreak known as the Spanish Flu. It is an orthomyxovirus that contains the glycoproteins haemagglutinin and neuraminidase. For this reason, they are described as H1N1, H1N2 etc., depending on the type of H or N antigens they express with metabolic synergy. - Haemagglutinin causes red blood cells to clump together and binds the virus to the infected cell. - Neuraminidase is a type of glycoside hydrolase enzyme which helps to move the virus particles through the infected cell and assist in budding from the host cells. In June 2009, the World Health Organization (WHO) declared the new strain of swine-origin H1N1 as a pandemic. This strain is often called swine flu by the public media.

**Statement 1 is correct:** Viruses that infect bacteria are known as bacteriophages or phages. These viruses use bacterial cells as hosts to replicate and propagate. **Statement 2 is correct:** Certain viruses, called mycoviruses, can infect and replicate within fungal cells, using them as hosts. **Statement 3 is correct:** Viruses that infect plants are known as plant viruses. They can hijack the cellular machinery of plant cells to replicate and spread within the plant. Hence, option D is the correct answer.

**Statement 1 is correct:** The Zika virus is primarily transmitted by the Aedes aegypti mosquito, which is the same mosquito that transmits the dengue virus in tropical and subtropical regions.  **Statement 2 is correct:** While Zika virus is primarily transmitted through mosquito bites, the virus can also be transmitted from person to person through sexual contact. Therefore, both the statements 1 and 2 are correct.

All of the listed factors - birds, dust blowing, rain, and wind blowing - can contribute to the spread of plant diseases **Statement 1 is correct:** Birds can act as vectors, carrying and spreading plant pathogens from one location to another through their feathers, feet, or droppings. **Statement 2 is correct:** Dust and soil particles blown by the wind can carry and spread plant diseases, especially fungal spores and bacterial cells. **Statement 3 is correct:** Rain can splash and disperse plant pathogens, such as fungi and bacteria, from the soil or infected plant parts to uninfected plants. **Statement 4 is correct:** Wind can transport and spread airborne plant pathogens, such as fungal spores and bacterial cells, over long distances.

**Option A is correct.** Both Hepatitis B virus and HIV (Human Immunodeficiency Virus) can be transmitted through blood-to-blood contact, sexual contact, and from mother to child during childbirth. **Option B is incorrect.** Unlike Hepatitis C, there is a vaccine available for Hepatitis B. The Hepatitis B vaccine is highly effective in preventing Hepatitis B virus infection. **Option C is correct.** According to global health statistics, the number of people infected with Hepatitis B and C viruses combined is indeed several times more than those infected with HIV. **Option D is correct.** Many individuals infected with Hepatitis B and C viruses may not show any symptoms for years or even decades. This is known as chronic hepatitis, and it can lead to severe liver damage if left untreated. 

**Statement 1 is incorrect.** While genetic factors can contribute to susceptibility to infections, they are not directly related to the occurrence of multi-drug resistance in microbial pathogens. **Statement 2 is correct.** Incorrect use of antibiotics, including taking incorrect doses or not completing the full course of treatment, can contribute to the development of drug resistance in microbial pathogens. **Statement 3 is correct.** The widespread use of antibiotics in livestock farming can lead to the development of drug-resistant pathogens that can affect both animals and humans. **Statement 4 is incorrect.** While individuals with chronic diseases may be more susceptible to infections, this factor is not directly related to the occurrence of multi-drug resistance in microbial pathogens.

* **Bacteria** can be cultured and grown in various artificial culture media, such as nutrient broth, agar plates, or other specific media formulations. Bacteria can metabolize and utilize the nutrients provided in these synthetic culture media to grow and reproduce. * **Fungi** can also be cultured in artificial media, such as potato dextrose agar, Sabouraud dextrose agar, or other specialized fungal growth media. Fungi can utilize the organic compounds and nutrients present in these synthetic media to support their growth and development. * **Viruses**, on the other hand, are obligate intracellular parasites and cannot be directly cultured in artificial or synthetic media. Viruses require living host cells to replicate and propagate, as they lack the necessary machinery for autonomous growth and reproduction.

* **Cnidarians:** Many cnidarian species, such as corals, develop symbiotic relationships with single-celled algae called zooxanthellae. This symbiosis is crucial for the survival and growth of coral reefs. * **Fungi:** Fungi are known to form various symbiotic relationships with other organisms, including * Mycorrhizal associations with plant roots, where the fungus helps the plant absorb nutrients in exchange for carbohydrates. * Lichens are a symbiotic relationship between a fungus and an algae or cyanobacteria. * **Protozoa:** Some protozoa living in the digestive tracts of termites and ruminant animals, helping them break down cellulose. Therefore, all three groups - cnidarians, fungi, and protozoa - have species that can form symbiotic relationships with other organisms.

* The term 'ACE2' is talked about in the context of the spread of viral diseases, particularly COVID-19. * ACE2 stands for Angiotensin-Converting Enzyme 2. It's a protein found on the surface of many cell types in the human body, including those in the lungs, heart, kidneys, and intestines. * Here's why ACE2 is significant: * **Receptor for SARS-CoV-2:** The spike protein on the surface of the SARS-CoV-2 virus, the virus that causes COVID-19, binds to the ACE2 receptor in human cells. This binding is a critical step in the process of how the virus infects cells. * **Multiple organ infection:** Since ACE2 is expressed in various organs, it provides the virus with multiple potential entry points. This can contribute to the multi-organ complications sometimes associated with COVID-19. * **Focus of research:** Understanding the interaction between the virus and ACE2 is a major area of research for scientists developing vaccines and treatments for COVID-19.

**Statement 1 is incorrect:** Adenoviruses have double-stranded DNA genomes. Retroviruses have single-stranded RNA genomes. **Statement 2 is correct:** Adenoviruses are one of the many viruses that can cause the common cold. AIDS (Acquired Immunodeficiency Syndrome) is caused by the Human Immunodeficiency Virus (HIV), which is a type of retrovirus.

B cells and T cells are both key components of the human immune system, which defend the body against harmful invaders like viruses, bacteria, and parasites. B cells produce antibodies that can specifically target and neutralize pathogens. T cells help orchestrate the immune response by directly attacking infected cells or by stimulating other immune cells. 

* **Statement 1 is correct:** Pyrolobus fumarii, an archaeon living at 113 °C in Atlantic hydrothermal vents.Pyrococcus furiosus, an archaeon which thrives at 100 °C, first discovered in Italy near a volcanic vent. * **Statement 2 is correct:** Psychrophiles or cryophiles (adj. psychrophilic or cryophilic) are extremophilic organisms that are capable of growth and reproduction in low temperatures, ranging from 20 °C to 20 °C. * **Statement 3 is correct:** Acidophiles are microorganisms that show optimal growth in highly acidic environments. These are of two types. The extreme acidophiles dwell in environments with a pH value < 3, and moderate acidophiles grow optimally in conditions having pH values ranging between 3 and 5.

 The Wolbachia method is a biological method that utilises the Wolbachia bacteria to control the spread of mosquito-borne diseases, particularly dengue fever. * Wolbachia naturally infects some insect species, but not Aedes aegypti mosquitoes, the primary vector for dengue fever transmission. Scientists introduce Wolbachia into Aedes aegypti populations. Wolbachia reduces the ability of these mosquitoes to transmit dengue virus. * As Wolbachia spreads through the mosquito population, it can significantly reduce the incidence of dengue fever. * This method offers a natural and sustainable approach to controlling dengue fever, a major public health concern in tropical and subtropical regions.

 **All four statements are correct.** * Medicinal mushrooms: Certain mushroom species have been used in traditional medicine for centuries and are still being studied for their potential health benefits. Examples include reishi mushrooms (Ganoderma lucidum) for immune system support and lion's mane mushrooms (Hericium erinaceus) for cognitive function. * Psychoactive mushrooms: Some mushrooms contain psilocybin, a naturally occurring psychoactive compound that can induce hallucinations. These are commonly referred to as "magic mushrooms" or psilocybin mushrooms. * Insecticidal mushrooms: Some mushroom species produce natural compounds that can repel or even kill insects. These compounds act as a defence mechanism for the mushrooms against insect pests. * Bioluminescent mushrooms: A less common but fascinating property, bioluminescence, is found in some mushroom species. These mushrooms can produce and emit light, creating a glowing effect.

**Viruses can survive in oceans, infect bacteria, and alter host cell transcription.** ❌**Statement I:** False. Viruses can survive in ocean waters, and marine viruses are highly abundant. ❌**Statement II:** False. Viruses can infect bacteria; for example, bacteriophages specifically infect bacteria. ❌**Statement III:** False. Viruses can alter host transcription and modify host gene expression. **None of the statements are correct.**

Monoclonal antibodies are lab-made proteins that target specific antigens and can be used to treat viral infections like Nipah virus. * ✅ **I. Man-made proteins** – Created by cloning a single immune cell type. * ✅**II. Bind to specific antigens** – Help stimulate or guide immune response. * ✅**III. Used in viral infections** – Applied in treating infections like Nipah virus. **All three statements are correct.**