Chapter 7: Human Health and Diseases

Public health measures are the measures taken to prevent and check the spread of different infectious diseases. It is taken to lessen contact with infectious agents.

Some of these preventive measures are as follows:

• Isolation – It prevents the spreading of airborne diseases (chicken pox, pneumonia, tuberculosis, etc.). We isolate an infected person to reduce the chances of the disease spreading.
• Vaccination – It protects the body against communicable diseases by administering some agents that impersonate the microbe in the body. This helps in rendering passive immunization to the body. Vaccines are available for some diseases, such as mumps, polio, measles, etc.
• Vector eradication – Diseases such as dengue, malaria, etc., that spread through vectors can be prevented by ensuring a clean environment and checking the breeding of mosquitoes which is facilitated by regulating water, and not letting it stagnate near residential areas. Some other measures are periodic cleaning of coolers and the use of mosquito nets and insecticides. It can also be controlled by introducing Laxvivorous fish such as Gambusia in ponds, as they control mosquito larvae breeding in stagnant water.
• Maintaining public and personal hygiene is one of the most important practices to prevent the spread of infectious diseases. It includes maintaining a clean body, consuming healthy and nutritious food, clean water, etc. Proper disposal of wastes, excreta, and disinfection of water reservoirs are some of the measures that can be adapted as part of public hygiene.

Biology is a vast field of Science dealing with life forms and their processes. It has helped in controlling infectious diseases in the following ways:

• Complete eradication of fatal diseases such as smallpox was possible with the use of immunization schemes and vaccines
• Other infectious diseases, such as diptheria, polio, pneumonia, etc., have been successfully controlled with the use of vaccines
• Treatment of several infectious diseases have successfully been carried out with the use of antibiotics and other drugs

The transmission of diseases is as given in the table:

Measures taken to prevent water-borne diseases are as follows:

• Provision of clean water for drinking
• Industries should be prohibited from discharging wastes into water bodies
• Frequent cleaning and disinfecting of water tanks and reservoirs

The term ‘suitable gene’ is used to refer to a particular section of DNA that can be altered in the host in order to synthesize a particular protein which attacks and kills a specific disease-causing entity.

Primary lymphoid organs are – Thymus and bone marrow

Secondary lymphoid organs are – Mucosal-associated lymphoid tissues (MALT), Lymph nodes, Spleen, Peyer’s patches (small intestine)

The expansion is as follows:

(a) MALT – Mucosal-Associated lymphoid tissues

(b) CMI – Cell-mediated Immunity

(c) AIDS – Acquired Immuno-Deficiency Syndrome

d) NACO – National Aids Control Organization

(e) HIV – Human Immuno-deficiency Virus

The differences are as follows:

(a) Innate and acquired immunity

(b) Active and passive immunity

The diagram is as follows:

The various routes by which transmission of the human immunodeficiency virus (HIV) takes place are as follows:

• Sexual relation with the person infected
• Organ transplantation from an infected person
• Transfusion of contaminated blood products and blood
• Transmitted from mother to the child through the placenta