Biological Hazards Chapter 20 Section 2

Global Warming Affects  Wide Spread of global warming allows mosquitoes to flourish in regions of the world they never could before.  The mosquitoes bring a variety of diseases with them.

The Environment’s Role in Disease  Infectious diseases are caused by pathogen, organisms that cause disease.  These diseases spread through person to person contact through the air or drinking water.  A host is an organism in which a pathogen lives all or part of its life.

Waterborne Disease  About ¾ of infectious diseases are transmitted through water.  In developing countries, there is a shortage of water so the water supply is used for drinking, washing and sewage disposal.  These are good breeding grounds for pathogens.  Organisms that transmit diseases are called vector s.

Cholera  Deadliest waterborne diseases come from drinking polluted water by human feces.  Cholera causes the body to lose water by diarrhea and vomiting.  It causes the most infant mortality.

Malaria  Once the world’s leading cause of death.  Caused by parasitic protists and is transmitted by a bite from female mosquitoes.  No vaccine for malaria exists but there are preventative measures to control mosquitoes.

Environmental Change and Disease  We alter the environment to make it more suitable for pathogens to live and reproduce.  Many organisms spread through soil that is contaminated with feces. Ex. Hookworm  People are infected by walking barefooted and contaminated food.

Antibiotic Resistance  Antibiotics cause pathogens to evolve  Large quantities of antibiotics are feed to live stock to speed growth causing Salmonella and E.Coli to evolve.  Treating human illnesses has also caused diseases such as pneumonia and tuberculosis to evolve

Emerging viruses  Viruses that were unknown 100 years ago. Ex. HIV/AIDS, ebola virus, West Nile virus.  We do not have any effective drugs to treat viral diseases.  Vaccines are only effective to a virus that is already present.

Cross Species Transfers  When pathogens cross over from its original host to a new host.  Ex. HIV, West Nile  Recent Examples include the bird flu and the swine flu.