Diseases of infectious origin whose incident in humans has increased within the past two decades or threatens to increase in the near future are referred to as emerging infectious diseases. Since 1980 Centre for Disease Control and Prevention (CDC) has reported a 58 percent rise in death of infectious diseases worldwide. There are reasons for emergence of infectious disease. Ecological changes, human demographic changes, travel and commerce, technology and industry, microbial adaptation and change and breakdown of public health measures are factors responsible for the emergence of infectious disease. Specific emerging diseases in the world are viruses, bacteria and parasites diseases. The viruses diseases include; hanta virus, dengue fever, influenza, Ebola and AIDS/HIV. The bacteria diseases are Escherichia coli, Lyme disease, Streptococcus and tuberculosis. Cryptosporidium and malaria are the parasite diseases. Due to emergence of 29 new infectious diseases and re-emergence of many others are creating national and international crises, a practical approach has been developed to limit the emergence of infectious diseases.
Chapter 5: a chapter about toxicity and toxins.Emerging diseases
Currently in United States there are more than 70,000 synthetic chemicals in commercial use and mostly their toxicity is not widely known or understood. There is significant chance for untested materials in each year to enter environment and expose humans, wildlife and plants to toxic effect since 1,000-2,000. Toxic substances are those that: cause reversible or irreversible bodily injury, cause tumors , cause reproductive error, produce irritation or sensitization of mucous membrane, affect someone mentally and lead to death . After an individual is exposed to toxic substances they are absorbed into the body through diffusion, active transport, or special process. Toxic substances enter inside an organism through lungs, skin, mucous membrane or eyes and gastrointestinal. The principal mechanisms that show harmful effect of environmental toxins include; toxic influence on enzymes, direct chemical combination of the toxin with a cell constituent and secondary action as a result of toxins presence in the system. The outcome of toxic exposure depends on certain factors. Endocrine Disrupters and Reproductive Health, Hormone Function, Androgens and Estrogens are special examples of toxic agents. Mercury, asbestos, organic solvents, lead, polychlorinated biphenyls (PCBs) and dioxins are example of toxic substances.Emerging diseases