A model of the papillomavirus capsid is shown beside a computer colorized EM image.

a human adenovirus

Autographa californica nucleopolyhedrovirus

This nasty little virus causes genital warts

This virus causes a serious illness called ‘West Nile’ disease and is passed onby mosquitoes – see next page

People who contract West Nile virus usually experience only mild symptoms-fever, headache, body aches, skin rash, and swollen lymph glands. If West Nile virus enters the brain, however, it can cause life-threatening encephalitis (inflammation of the brain) or meningitis (inflammation of the lining of the brain and spinal cord).

West Nile virus is an emerging infectious disease that made its first appearance in the United States in 1999. The microbe that causes the infection belongs to a group of disease-causing viruses known as flaviviruses, which are usually spread by ticks or mosquitoes. Other well-known diseases caused by flaviviruses include yellow fever, Japanese encephalitis, dengue, and Saint Louis encephalitis.

Ebola virus Reston

Rabies virus

several influenza viruses

Diagram of rabies structure

The symptoms of influenza (flu) appear suddenly and often include:Fever of 100 °F(37.8 °C) to 104 °F(40 °C), which can reach 106 °F(41.1 °C) when symptoms first develop. Fever is usually continuous, but it may come and go. Fever may be lower in older adults than in children and younger adults. Shaking chills. Body aches and muscle pain (often severe), commonly in the back, arms, or legs. Headache. Pain when you move your eyes. Fatigue, a general feeling of sickness (malaise), and loss of appetite. A dry cough, runny nose, and a dry or sore throat. You may not notice these during the first few days of the illness when other symptoms are more severe. As your fever goes away, these symptoms may become more evident.

Ebola [ee-BO-luh] hemorrhagic fever is a deadly disease that has occurred in outbreaks in Central Africa. Ebola hemorrhagic fever is caused by several Ebola viruses. The source of these viruses in nature is not known. People can get Ebola hemorrhagic fever by direct contact with virus-infected blood, body fluids, organs, or semen. There is no known cure or treatment. Recent outbreaks in humans have occurred in areas where medical supplies and care were inadequate. The outbreaks were controlled by using barrier nursing techniques. Under normal circumstances, travellers are at low risk of getting the disease. To eliminate the risk, travellers should avoid areas where Ebola outbreaks are occurring.

The average incubation period (time from infection to time of development of symptoms) in humans is 30-60 days, but it may range from less than 10 days to several years.

Most people first develop symptoms of pain, tingling, or itching shooting from the bite site (or site of virus entry).

Nonspecific complaints of fevers, chills, fatigue, muscle aches, and irritability may accompany these complaints. Early on, these complaints may seem like any virus, except for the shooting sensations from the bite site.

Gradually, however, you will become extremely ill, developing a variety of symptoms, including high fever, confusion, agitation, and eventually seizures and coma.

Typically, people with rabies develop irregular contractions and spasms of the breathing muscles when exposed to water (this is termed hydrophobia). They may demonstrate the same response to a puff of air directed at them (termed aerophobia). By this point, they are obviously extremely ill.

Eventually, the various organs of the body are affected, and the person dies despite support with medication and a respirator.

Poxviruses

bacteriophage T4

bacteriophage T4 – infecting

cell

Smallpox was transmitted by respiratory route from lesions in the respiratory tract of patients in the early stage of the disease. During the 12 day incubation period, the virus was distributed initially to the internal organs and then to the skin. Variola major caused severe infections with 20-50% mortality

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human T-lymphotropic virus (HTLV)

human immunodeficiency viruses

Persistent or severe symptoms may not appear for 10 years or more after HIV first enters the body in adults, or within 2 years in children born with HIV infection. This period of

"asymptomatic" infection varies greatly in each individual. Some people may begin to have symptoms within a few months, while others may be symptom-free for more than 10 years. Even during the asymptomatic period, the virus is actively multiplying, infecting, and killing cells of the immune system. The virus can also hide within infected cells and lay dormant.

The most obvious effect of HIV infection is a decline in the number of CD4 positive T (CD4+) cells found in the blood-the immune system's key infection fighters. The virus slowly disables

or destroys these cells without causing symptoms. As the immune system worsens, a variety of complications start to take over. For many people, the first signs of infection are large lymph nodes or "swollen glands" that may be

enlarged for more than 3 months. Other symptoms often experienced months to years before the onset of AIDS include

Lack of energy Weight loss

Frequent fevers and sweats Persistent or frequent yeast infections (oral or vaginal)

Persistent skin rashes or flaky skin Pelvic inflammatory disease in women that does not respond to treatment

Short-term memory loss Some people develop frequent and severe herpes infections that cause mouth, genital, or

anal sores, or a painful nerve disease called shingles. Children may grow slowly or be sick a lot.

The term AIDS applies to the most advanced stages of HIV infection. CDC developed official criteria for the definition of AIDS and is responsible for tracking the spread of

AIDS in the United States. CDC's definition of AIDS includes all HIV-infected people who have fewer than 200 CD4+ T cells per cubic millimeter of blood. (Healthy adults usually have CD4+ T-cell counts of 1,000 or more.) In addition, the definition includes 26 clinical conditions that affect people with advanced HIV disease. Most of these conditions are opportunistic

infections that generally do not affect healthy people. In people with AIDS, these infections are often severe and sometimes fatal because the immune system is so

ravaged by HIV that the body cannot fight off certain bacteria, viruses, fungi, parasites, and other microbes.

Symptoms of opportunistic infections common in people with AIDS include Coughing and shortness of breath Seizures and lack of coordination

Difficult or painful swallowing Mental symptoms such as confusion and forgetfulness

Severe and persistent diarrhea Fever

Vision loss Nausea, abdominal cramps, and vomiting

Weight loss and extreme fatigue Severe headaches

Coma

Children with AIDS may get the same opportunistic infections as do adults with the disease. In addition, they also have severe forms of the typically common childhood bacterial infections, such as conjunctivitis (pink eye), ear infections, and tonsillitis. People with AIDS are also particularly prone to developing various cancers, especially those caused by viruses such as Kaposi's sarcoma and cervical cancer, or cancers of the immune system known as lymphomas. These cancers are usually more aggressive and difficult to treat in people with AIDS. Signs of Kaposi's sarcoma in light-skinned people are round brown, reddish, or purple spots that develop in the skin or in the mouth. In dark-skinned people, the spots are more pigmented. During the course of HIV infection, most people experience a gradual decline in the number of CD4+ T cells, although some may have abrupt and dramatic drops in their CD4+ T-cell counts. A person with CD4+ T cells above 200 may experience some of the early symptoms of HIV disease. Others may have no symptoms even though their CD4+ T-cell count is below 200. Many people are so debilitated by the symptoms of AIDS that they cannot hold a steady job or do household chores. Other people with AIDS may experience phases of intense life-threatening illness followed by phases in which they function normally.

For more information click here

Pseudomonas syringae phage

human rotavirus

Human poliovirus 1

tobacco mosaic virus

tobacco mosaic virus - structure

Attacks: Virus attacks mature enterocytes in GI tract, destroying the absorptive surface area of the intestinal villi

Outcome: Severe dehydrating infantile diarrhoea; responsible for 500,000-800,000 deaths per year due to dehydration and electrolyte imbalance; vomiting,

then diarrhoea and feverSpeed: Incubation 1-3 days; die within 3 days

DefensesVaccine: Rotashield was recalled due to increased risk of intussusception

Behavioral: Sanitation does not help!Treatment: Rehydration therapy (oral or parenteral)

Game Action: Run as fast as you can to the nearest toilet! Then drink a lot of Gatorade.

One liner: "Run, run, as fast as you can, you can't escape me, I'm the severe diarrhoea causing man"

Paralytic polio is classified into three types, depending on the level of involvement: Spinal polio is most common, and accounted for 79% of paralytic cases from 1969-1979. It is characterized by asymmetric paralysis that most often involves the legs. Bulbar polio accounted for 2% of cases and led to weakness of muscles innervated by cranial nerves. Bulbospinal polio accounted for 19% of cases and was a combination of bulbar and spinal paralysis. The death-to-case ratio for paralytic polio is generally 2%-5% in children and up to 15%-30% in adults (depending on age). It increases to 25%-75% with bulbar involvement.

Tobacco mosaic damages the leaves, flowers, and fruit and causes stunting of the plant. The virus almost never kills plants but lowers the quality and quantity of the crop, particularly when the plants are infected while young.