Disease Causative Agents

Norovirus is widely recognized as the leading cause of foodborne illness in the United States.

E.coli strains are normally present in the large intestines where they help in the production of Cyanocobalamin (Vitamin B12).

Cobra venom contains neurotoxins that primarily target the nervous system, leading to paralysis and respiratory failure by blocking nerve impulses.

Gastrointestinal diseases refer to diseases involving the gastrointestinal tract, namely the esophagus, stomach, small intestine, large intestine and rectum, and the accessory organs of digestion, the liver, gallbladder, and pancreas.

E. coli (Escherichia coli) is the name of a germ, or bacterium,that lives in the digestive tracts of humans and animals. There are many types of E. coli, and most of them are harmless. But some can cause bloody diarrhea.

Enterococcus faecalis – formerly classified as part of the group D Streptococcus system – is a Gram-positive, commensal bacterium inhabiting the gastrointestinal tracts of humans and other mammals

Minamata disease, sometimes referred to as Chisso-Minamata disease, is a neurological syndrome caused by severe mercury poisoning. Symptoms include ataxia, numbness in the hands and feet, general muscle weakness, narrowing of the field of vision and damage to hearing and speech. Nearby anthropogenic sources, such as coal burning and mining of iron, can contaminate water sources with methylmercury, which is efficiently absorbed in the bodies of fish. Fish and shellfish concentrate mercury in their bodies, often in the form of methylmercury, a highly toxic organic compound of mercury. Minamata disease was first discovered in Minamata city in Kumamoto prefecture, Japan, in 1956. It was caused by the release of methylmercury in the industrial wastewater from the Chisso Corporation's chemical factory, which continued from 1932 to 1968. This highly toxic chemical bioaccumulated in shellfish and fish in Minamata Bay and the Shiranui Sea, which, when eaten by the local populace, resulted in mercury poisoning.

Soil bacterium Bacillus thruingiensis (Bt) produces proteins that kill certain insects like lepidopterans (tobacco dudworm, armyworm), coleopterans (beetals) and dipterans (files, mosquitoes).Bacillus thuringinesis forms some intracellular protein crystals. These crystals contain a toxic insecticidal protein. The Bt toxin protein exists as inactive toxin and is coverted into an active form due to the alkaline pH of the alimentary canal that solubilities the crystals. The activated toxin binds to the surface of midgut epithelial cells and create pores which cause cell swelling and lysis and finally cause death of the insect.

Soil bacterium Bacillus thruingiensis (Bt) produces proteins that kill certain insects like lepidopterans (tobacco budworm, armyworm), coleopterans (beetles) and dipterans (flies, mosquitoes).Bacillus thuringinesis forms some intracellular protein crystals. These crystals contain a toxic insecticidal protein. The Bt toxin protein exists as an inactive toxin and is converted into an active form due to the alkaline pH of the alimentary canal that solubilities the crystals. The activated toxin binds to the surface of midgut epithelial cells and creates pores which cause cell swelling and lysis and finally cause the death of the insect.

• Watery diarrhoea, hypokalemia, achlorhydria, is caused by overproduction of vasoactive intestinal peptide (VIP) which stimulates fluid and electrolyte secretion in the intestinal epithelium via activation of the cyclic adenosine monophosphate pathway. Hence, Hypokalemia is caused by the overproduction of VIP.

Communicable diseases are infectious diseases that can be transmitted from one person to another through various mediums, including contaminated water, food, and air.

While diseases like Small Pox have been eradicated and Polio has been largely controlled, HIV/AIDS has historically shown an increasing trend in many regions over the past few decades.

Small Pox was declared globally eradicated by the World Health Organization in 1980, making it the only human disease to be completely eradicated.

Pneumonia can cause by a virus, fungi, bacteria, etc. They can be transmitted from a contaminated person to a healthy person by sneezing, coughing, contaminated objects, air, etc. Thus it is considered as a communicable disease. So, the correct answer is option A.

• Infectious diseases are those diseases which are caused by microorganisms like fungi, bacteria, virus, parasites. 
• Diphtheria is an infectious disease caused by the bacterium Corynebacterium diphtheria. It affects the mucous membrane of the throat and upper respiratory tract. Coronary thrombosis is caused due to accumulation of cholesterol in the walls of arteries. 
• Cancer is caused by mutation, radiation, etc. Diabetes mellitus is caused by insufficient production of insulin.

Infectious diseases are those that can spread from a diseased person to a healthy person. They are also called communicable diseases. 

Jaundice is a non-communicable infectious disease that is caused due to excessive secretion of bilirubin, that is not completely filtered by the blood. It is mostly caused due to Hepatitis virus, that infects the hepatic system.