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Viruses A virus is a sub- microscopic infectious agent only capable of reproducing within a host cell. Virus is Latin for toxin or poison.

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Presentation on theme: "Viruses A virus is a sub- microscopic infectious agent only capable of reproducing within a host cell. Virus is Latin for toxin or poison."— Presentation transcript:

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2 Viruses A virus is a sub- microscopic infectious agent only capable of reproducing within a host cell. Virus is Latin for toxin or poison.

3 Viruses Viruses infect all types of organisms. They are transmitted by every type of vector. They are basically a nucleic acid covered in a protein shell (capsid). Can cause minor illness up to a deadly disease.

4 Make sure you know one or two really well…

5 Influenza Viruses Contain all types of flu viruses from “seasonal flu” to Avian Flu to Spanish Flu (a.k.a. H1N1). Most influenza viruses affect humans only, but some can crossover species. Common transmission is airborne or waterborne. Annoying, but usually not deadly (H1N1 may be an exception).

6 Varicella zoster This virus causes chicken pox. Causes skin rash and lesions. Common transmission is airborne or contact. Annoying, but usually not deadly although affected adults get it worse than children.

7 Herpes simplex virus Two strains of this virus affect humans. One causes cold sores and the other causes watery blisters on the mucous membranes of the genitals. Transmission is close contact. Not deadly, more than annoying though as the virus remains in the cells for life and reoccurrences are frequent.

8 Norovirus Formerly Norwalk Virus. Causes fun things like nausea, vomiting, diarrhea, mild fever… Common transmission is fecal-oral, which basically means someone did not wash their hands after a bathroom break and then handled your food. Also can be waterborne. Very harsh, but only lasts 1-2 days… not deadly unless you are really old or really young.

9 Bacteria Bacteria are unicellular micro-organisms ranging in length from a few micrometers to half a millimeter. They come in a variety of different shapes (cocci, bacilli and spirilli). Bacteria can be found in almost every ecosystem on Earth. There are an estimated 5 x 10 30 bacteria on Earth!

10 Bacteria Introduction Bacteria are found all over the human body, however the majority are harmless or even beneficial. Some bacteria are pathogenic and cause disease.

11 Make sure you know one or two really well…

12 Streptococcus pyogenes Chain of round bacteria. Causes strep throat. Can lead to the “flesh eating disease” in some cases! Common transmission is airborne or contact. Annoying… flesh eating disease can be deadly.

13 Staphylococcus aureus Grape like clusters of bacteria that produce a toxin which can cause minor skin infections like pimples or deadly infections like pneumonia, meningitis, toxic- shock syndrome and sepsis. Methicillin-Resistant S. aureus (MRSA) is more common now in hospitals and is hard to kill, therefore more patients succumb to infection. Common transmission is contact. Annoying right up to deadly.

14 E. Coli 0157-H7 A pathogenic strain of a usually harmless bacteria. Causes severe gastrointestinal problems like bloody stool, cramps and in severe cases, kidney failure. Common transmission is waterborne or eating undercooked ground beef. Severe, but usually brief, however there always is a chance of death.

15 Acinetobacter baumannii Called “Iraqibacter” as it has hit troops in the Middle East hard. Causes sepsis and in some cases pneumonia. Common transmission is contact with open wounds. Sepsis will kill 3 out of 4 sufferers! A good bacterium to avoid at all costs.

16 Fungi Look similar to a plant by also have much in common with animals Feed by releasing digestive enzymes into the surrounding environment and absorb the digested nutrients into their cells Some pathogen species.

17 Make sure you know one or two really well…

18 Ringworm Feeds on the protein keratin found in skin, hair and nails. Loves warm, moist skin. Causes an itchy “ring” to develop on the skin. Common transmission is contact. Annoying, but not deadly.

19 Tinea pedis Athlete's foot fungus.. Causes skin to be scaly and flake off. Affects the feet but can be passed on to other areas of the body. Common transmission is contact. Can be painful if left untreated, but not deadly.

20 Candida species A group of yeast. Causes yeast infections (thrush). Itchy, burning sensation. Common transmission is contact. Can be severe if left untreated, but rarely deadly.

21 Aspergillus species Big group of about 200 molds. Found in some nuts and can be carcinogenic! Causes allergies, sinus and lung infections. Common transmission is airborne or contact. Mild to severe discomfort.

22 Protists Microscopic organisms that have a nucleus. Most do not bother us. A few are pathogenic.

23 Make sure you know one or two really well…

24 Trypanosoma species Move by a spiral motion. Causes African sleeping sickness of Chagras’ disease. Both affects the nervous system. Common transmission is through an insect vector (Tsetse fly or mosquito). Can be fatal if not treated.

25 Plasmodium species Move by a spiral motion. Causes malaria which is a red blood cell disease. Complex life cycle in a human and mosquito. Common transmission is through an insect vector (Anopheles mosquito) Can be fatal if not treated.

26 Giardia lamblia Causes “Beaver Fever” It attaches to the small intestine’s lumen (inside) and absorbs nutrients from food the host digests. Common to humans, beavers, dogs, cats, birds, deer and sheep. Common transmission is waterborne although fecal-oral is another route. Severe sickness and lethargy, but not usually deadly if treated.

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28 Prions These are misfolded proteins that force other proteins in the host to misfold. These misfolded proteins tend to build up in the central nervous system and cause nasty things like Mad Cow Disease and Creutzfeldt- Jakob Disease… both lead to dementia and death.


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