Science Answer the questions.[Bio-5M]

Typhoid fever (TF) is one of the most common infectious diseases in developing countries. Early and definitive diagnosis of the disease is not only important in relieving patients’ suffering, but also critical in avoiding fatal complications such as perforation of the intestines. It also makes possible specific treatment at an early stage, which leads to the rapid elimination of the pathogen from the chronic patient’s excreta, especially stool, become a constant source of spread of the disease. Tuberculosis (TB) is one of the oldest known human infectious diseases, primarily affects lungs and causes Pulmonary TB(PTB), also can affect intestine, meninges, bones and joints, lymph glands, skin and other tissues of the body. It’s one of the three primary diseases of poverty along with AIDS and malaria, it may cause to death ranging between 10-15 people every year in the developing world. So both the diseases are dangerous if not cured and administered properly.

Viruses have few genes, sometimes less than 10, and thus few proteins that can be targeted. By contrast, bacteria have thousands of different genes and proteins. There are just more targets to shoot at with bacteria. Bacteria (except in spore stages) must be continuously active metabolically, and thus can be poisoned at any time. Viruses are metabolically inert until they have already infected a host cell, and are not susceptible to the actions of antivirals until then. An exception would be drugs that block viral adhesion to host cells, thus preventing their entry.

Viruses use a lot of host cell proteins for their replication and spread. Any drug that targets host cell proteins will be toxic to the host. Viruses often hijack host genes, and thus their proteins can be closely related to host proteins. Making a drug that discriminates between viral and host versions of a protein is very very difficult. Viruses are far more diverse than bacteria. Whereas most antibiotics are effective against many different species of bacteria, antivirals usually are very specific to one type of virus.

HIV attaches to these CD₄ cells. The virus then infects the cells and uses them as a place to multiply. In doing so, the virus destroys the ability of the infected cells to do their job in the immune system. The body then loses the ability to fight many infections. HIV is a unique human RNA virus, capable of infecting cells of the immune system. Specifically, HIV targets T helper cells (CD₄ cells), leading to the eventual death of the cell. CD₄ cells are vital players in the regulation of immune responses to invading microorganisms. In an untreated person, 10 billion to 100 billion new viruses are produced per day. This massive viral replication leads to a progressive loss of CD₄ cells over a period of several years to as long as a decade. And destruction of CD₄ cells renders a patient vulnerable to unusual opportunistic infections (OIs) that are rarely seen in healthy humans. Most patients who die from AIDS succumb to one or more infections.

1. Principles of treatment:

• To reduce the symptoms of disease.
• To remove the cause of disease.
• To prevent the cause of disease.
• To prevent the spread of disease.
• To make the patient healthy again by helping him to overcome the effects of the diseases like weakness etc.

2. Vaccination: A vaccine is a product that produces immunity from a disease and can be administered through needle injections, by mouth, or by aerosol. A vaccination is the injection of a killed or weakened organism that produces immunity in the body against that organism. An immunization is the process by which a person or animal becomes protected from a disease. Vaccines cause immunization, and there are also some diseases that cause immunization after an individual recovers from the disease.

These diseases involve temporary or permanent damage to the body and include all the other categories except mental disease where there is no sign of physical damage to the brain. An example would be leprosy.

• Pathogens: They are organisms living in or on our bodies, causing disease. Infectious diseases are caused by pathogens such as viruses, bacteria, fungi, protoctists, worms and insects, which can be transmitted from person to person. This may be via normal social contact. For example, chicken pox, or via food and water, sexual contact or an animal bite. Carriers are people who can transmit the pathogen but do not have the disease symptoms.

• Non-infectious diseases: These are all diseases, which are not caused by pathogens and cannot be passed on by physical contact. An example would be sickle cell anaemia.

• Deficiency diseases: These are nutritional diseases caused by an inadequate or unbalanced diet. One or more essential nutrient is missing or in short supply. For example, a shortage of Vitamin C causes scurvy.