Disease Causative Agents

A capsid is the protein shell of a virus, and peplomers are glycoprotein spikes on the viral envelope; these are characteristic features of viruses.

Helpful bacteria often occupy niches that prevent harmful bacteria from colonizing. When helpful bacteria are reduced, harmful bacteria have more space and resources to multiply.

Bacteria are diverse; some are pathogenic (causing disease), while others are beneficial (such as those in the gut microbiome that aid digestion).

Anthrax is a serious infectious disease caused by the bacterium Bacillus anthracis. The other options are either beneficial bacteria or different types of organisms.

Smallpox is a highly contagious disease caused by the variola virus. It is a classic example of a viral disease.

Arsenic comes from bedrock as well as surface leaching. Chronic exposure leads to repeated diarrhoea, peripheral neuritis, hyperkeratosis, transverse striations on fingernails, peripheral vascular insufficiency, vasospasm, hyperpigmentation leading to 'Black Foot Disease', lung inflammation, skin and lung cancer.

• An endemic disease is a disease that exists permanently in a particular region or population. Poor sanitation is linked to transmission of some endemic diseases such as cholera, diarrhea, dysentery, hepatitis A, typhoid and polio
• Hence the disease caused due to improper sanitation in public place is endemic diseases.
  
• So, the correct answer is 'Endemic'.

• A disease can spread from one person to population by improper sanitation in public places because many disease-causing organisms can survive on the surface of the improperly sanitized public toilet seat, and for an infection to occur, the germs(bacteria, virus) would have to be transferred from the toilet seat to your urethral or genital tract, or through a cut or sore on the buttocks or thighs, which is possible.
• Hence A disease can spread from one person to population by improper sanitation in public places.
• So, the correct answer is 'improper sanitation in public places'.

• Sanitation refers to public health conditions related to clean drinking water and adequate treatment and disposal of human wastes and sewage. Preventing human contact with feces is part of sanitation.
  
• Poor sanitation is linked to transmission of diseases such as cholera, diarrhea, dysentery, hepatitis A, typhoid and polio because these diseases can be transmitted through the fecal-oral route when food or water is contaminated.
• Hence Disease caused due to poor sanitation is typhoid and polio.
• So, the correct answer is 'Both B and C'.

Water-borne diseases are caused by the ingestion of water contaminated by pathogenic microorganisms, specifically bacteria, viruses, and protozoa.

Lead poisoning can lead to fatal diseases one including anaemia. Lead inhibits certain enzymes required for the synthesis of heme molecule. Heme is an integral part of haemoglobin of the RBCs. It carries oxygen in the body and provides to the cells for aerobic respiration. Lead poisoning indirectly leads to the loss of oxygen-carrying capacity of the RBCs and in turn can be fatal. So, the correct answer is option D.

The Blackfoot disease affects the peripheral vascular system. It is endemic in nature. It is associated with the consumption of inorganic arsenic from the artesian wells. Arsenicosis is caused by exposure over a period of time to arsenic in drinking water. Arsenic contamination in water may also be due to industrial processes, such as those involved in mining, metal refining, and timber treatment. WHO's guideline value for arsenic in drinking water is 0.01 mg /litre.

AIDS (Acquired immunodeficiency syndrome) is an infection which is caused by Human immunodeficiency virus (HIV). The causative agent of the disease is a virus and so the disease can spread from one person to the other by sexual contact. The disease alsoe spreads through the use of teh infected needles, syringes and blood transfusion from the infected person.

AIDS is an infectious disease that spreads through sexual contact. It also spreads through blood transfusion, use of common needles and syringes or from infected mother to her baby during pregnancy or breast feeding.