Transcript Slide 1
Dis-ease May you live long, share much kindness, and always talk nicely to yourself Bacteria Bacteria grow in a wide variety of habitats and conditions. • When most people think of bacteria, they think of disease-causing organisms, like the Streptococcus bacteria growing in culture in this picture, which were isolated from a man with strep throat. • While pathogenic bacteria are notorious for such diseases as cholera, tuberculosis, and gonorrhea, such disease-causing species are a comparatively tiny fraction of the bacteria as a whole. • Bacteria are so widespread that it is possible only to make the most general statements about their life history and ecology. – – – – They may be found on the tops of mountains, The bottom of the deepest oceans, In the guts of animals, and even In the frozen rocks and ice of Antarctica. One feature that has enabled them to spread so far, and last so long is their ability to go dormant for an extended period (forming capsides to prevent desiccation or hard-coated materials creating a bacterial spore. Virus Viruses • Viruses are particles of nucleic acid, protein, and some cases lipids that can reproduce only by infecting living cells. • A typical virus is composed of a core of either DNA or RNA, surrounded by a protein coat. 1. A virus’s outer protein coat is called its capsid. 2. The capsid includes protein that enables a virus to enter a host cell. 3. The capsid proteins of a typical virus bind to the surface of a cell and “trick” the cell into allowing it inside. 4. Once inside, the viral genes take over, eventually. – The cell transcribes the viral genes, putting the genetic program of the virus into effect. – The virus may become part of the host’s genome – Sometimes that genetic program may simply cause the cell to make copies of the virus, but often it destroys the host cell. Pathogen Disease Type Viruses Agent that Methods of Transmission Causes Disease Common Cold Rhinovirus Airborne, direct contact with infected person Influenza Two types (A,B), plus subtypes Chicken Pox Varicella – Herpes virus Airborne, direct contact with infected person Measles Paramyxovirus Airborne, direct contact with infected person Acquired Immune Deficiency Syndrome Human Immunedeficiency Virus Body fluids Direct sexual contact Pathogen Type Disease Agent that Causes Disease Methods of Transmission Bacteria Tuberculosis Mycobacterium tuberculosis Droplets in air, direct contact with secretions of infected person Meningitis Neisseria meningitides Direct contact with a carrier Cholera Vibrio cholerae Contaminated drinking water Tetanus Clostridium tentani Contaminated wound, usually puncture wound African sleeping sickness Trypanosoma Spread by tsetse fly Malaria Plasmodium Spread by Anopheles mosquitoes Amoebic dysentery Entamoeba histolytica Contaminated drinking water Protists Malaria Infection Roll down your sleeves to cover exposed skin and avoid mosquito bites, especially in evening and early morning. One more reason to hate mosquitoes – West Nile Virus CNS infecting virus –West Nile Virus Human Disease Cases by County - California, 2004 Butte County - 7 Fresno County- 11 Glenn County - 3 Imperial County - 1 Kern County - 59 Lake County - 1 Lassen County - 1 Los Angeles County - 305 Merced County - 1 Orange County - 62 Placer County - 1 Riverside County - 109 Sacramento County - 3 San Bernardino County - 187 San Diego County - 2 San Joaquin County - 2 San Luis Obispo County - 1 Santa Clara County - 1 Shasta County - 5 Tehama County - 10 Tulare County - 3 Ventura County - 2 Yolo County - 1 • Cumulative 2004 Data as of 3 am, Apr 30, 2005* West Nile Virus is transmitted to humans through mosquito bites. Mosquitoes become infected when they feed on infected birds that have high levels of West Nile Virus in their blood. Infected mosquitoes can then transmit West Nile Virus when they feed on humans or other animals. Since West Nile virus (WNV) was first isolated in 1937, it has been known to cause asymptomatic infection and fevers in humans in Africa, West Asia, and the Middle East. These data are provisional and may be revised or adjusted in the future. More about the dreaded WNV • Human and animal infections were not documented in the Western Hemisphere until the 1999 outbreak in the New York City metropolitan area. Since then, the disease has spread across the United States. In 2003, WNV activity occurred in 46 states and caused illness in over 9,800 people. • Less than 1% of infected people develop severe illness that includes meningitis (inflammation of one of the membranes covering the brain and spinal cord) or encephalitis. • The symptoms of these illnesses can include headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, and paralysis. Of the few people that develop encephalitis, a small proportion die but, overall, this is estimated to occur in less than 1 out of 1000 infections. 2004 West Nile Virus Activity in the United States (reported as of January 11, 2005)* State Neuroinvasiv e disease California 156 269 346 771 23 900 1017 553 2470 88 Total Fever Other Clinical/ Unspecified Total Human Cases Reported to CDC Deaths Polio • And we thought it was over…… Thanks for the cartoon http://www.pbs.org/wgbh/aso/onth eedge/polio/