Biology 303: Microbiology
Microbiology in the News
The
final examination will include “Microbiology in the News”
information presented after October 26, 2001 only.
Pollack, Andrew. “Scientists Ponder Limits on Access to Germ
Research.” The New York Times, (www.nytimes.com) November 27, 2001.
Background: Genetics is the science of heredity; it includes studying the nature of genes and how gene expressions determine characteristics of a particular organism. The complete list of an organism's genetic information is called its genome. Genome mapping, which is not a new science, has many important uses in the world of science, including giving scientists the opportunity to compare similar organisms based on genetic structure. The most notable genome-mapping project began in 1990 with the beginning of The Human Genome Project. Many primitive, prokaryotic genomes have already been mapped, including genomes of deadly, microorganisms. Publication of the genomes of these microorganisms and all other genomes acts as a way for scientists to communicate their research findings and provide a basis for further research. (Biology, 5th edition by Campbell, N.A., J.B. Reece, and L.G. Mitchell (Menlo Park, CA : Benjamin/Cummings Publ. Co., 1999.), (Microbiology: An Introduction by G.J. Tortora, B.R. Funke, and C.L. Case, 7th edition (San Francisco, CA: Benjamin/Cummings Publ. Co., 2001, chapter 8).
Definitions:
Genome – The complete complement of an organism's genes; an organism's genetic material.
Antibiotic – An antimicrobial agent, usually produced by a bacterium or fungus
Vaccine – A preparation of killed, inactivated, or attenuated microorganisms or toxoids to induce artificially acquired active immunity
Nucleoside Analog – A chemical that is structurally similar to the normal nucleosides in nucleic acids but with altered base pairing
Summary: Recent acts of terrorism using agents of biological warfare have sent shockwaves through the scientific community. Many scientists fear their research, regarding the genome mapping of specific microorganisms, may aid in creating the next line of biological "superweapons." Many scientists feel the need to regulate research personnel and restrict the access to genome information. Proposals have already been presented to Congress to forbid foreigners from working in laboratories handling dangerous microbes. President Bush proposed formulating an international code of ethical conduct for biological scientists. On the other hand of the issue, many scientists believe restricting access to the genomic information will "impede research aimed at countering biological agents and treating infectious diseases." The scientific impact from the recent acts of terrorism is already apparent. The Institute for Genomic Research developed a synthetic microorganism created to study accelerated evolution, but did not publish the organism's genome in fear of the recent acts of terrorism. Australian research created a vaccine-resistant strain of mouse pox. They did publish their results after months of hesitation. Iowa State University destroyed their large collection of various strains of anthrax. No official restriction has been implemented on genomic access at this point, but some scientists are taking initiative in restricting the publication of their genomic findings, so they do not aid the terrorists' cause.
Presented by: Ryan Cragle on November 29, 2001
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Associated
Press. “Study: Drug cocktails help kids
with HIV.” CNN.com,
November 22, 2001.
Background: HIV is the human immunodeficiency virus and causes AIDS, acquired immunodeficiency syndrome. The virus attacks CD4 T cells of the immune system and suppresses the body’s natural defense against invasion. The condition is considered AIDS when the patient presents with one of twenty-five AIDS-indicative infections and when CD4 T cell counts fall below 200 cells per cubic millimeter of blood. There is no cure for HIV/AIDS. At the end of 1999 an estimated 34,300,000 people world-wide had AIDS, 1,300,000 of them children. Treatment for HIV/AIDS is most commonly seen in the form of drug cocktails which combine a number of different approaches to attacking the virus. Nucleoside analogues, such as zidovudine, resemble nucleosides and prevent the replication of RNA. Protease inhibitors, such as saquinavir, prevent the cleavage that activates proteins in the virus. Reverse transcriptase inhibitors, such as nevirapine, interfere with reverse transcriptase proteins. These drugs have helped to turn HIV and AIDS into a chronic disease instead of a certain fatality. (AVERT )
Definitions:
HIV-1: Human immunodeficiency virus, the virus that causes AIDS (Centers for Disease Control and Prevention )
AIDS: Acquired immunodeficiency syndrome; an HIV-infected person receives this diagnosis when they develop one of several defined AIDS indicator illnesses (Centers for Disease Control and Prevention )
T cells: specialized cells that attack foreign agents in the body and activate other immune responses. (Microbiology: An Introduction by G.J. Tortora, B.R. Funke, and C.L. Case, 7th edition, Menlo Park, CA: Benjamin/Cummings Publ. Co., 2001, chapter 17)
CD4 T cells: T cells that contain CD4 proteins which are complementary to HIV binding sites. (Microbiology: An Introduction by G.J. Tortora, B.R. Funke, and C.L. Case, 7th edition, Menlo Park, CA: Benjamin/Cummings Publ. Co., 2001, chapter 15)
Summary: A four-year study of 1,028 children and teenagers infected with HIV was conducted to assess the affects of combining protease inhibitors with standard AIDS drugs. This particular study found that protease inhibitors decrease the number of deaths from AIDS among of young people significantly. Many of the children improved showing signs of weight gain and growth and acquired fewer infections due to immune system suppression. Adults AIDS patients’ drug regimen often includes a protease inhibitor. However, before the late 1990s there was little information about the affects these drugs would have on children. Appropriate dose sizes, liquid forms, and troubling side effects like bone loss were all problems. With these problems solved it is now possible to due more research for children’s treatment. As the study showed, there are some promising results pointing to protease inhibitors in combination with standard AIDS drugs as a successful way to treat younger patients.
Presented by: Colleen Marie Guerin on November 27, 2001
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Hayden, Thomas.
“Bugs, bared.” U.S. News
& World Report, November 12, 2001, p. 68.
Background: DNA is the substance of which genes are made. ( Microbiology: An Introduction by G.J. Tortora, B.R. Funke, and C.L. Case, 7th edition, Menlo Park, CA: Benjamin/Cummings Publishing Co., 2000, Chapter 2)
Definitions:
Adhesins- a binding protein that projects from prokaryotic cells and is used for adherence
Pathogencity islands- gene clusters found in microbes that give the pathogenic agent the ability to produce a disease
Summary: Since most bacteria are not harmful, scientists researched why different strains of the same bacteria can have deleterious effects. Upon studying 50 different strains of bacteria they discovered 5 genomes that had never been seen before. Specific, known DNA sequences are suspected to be associated with bacterial virulence.
Presented by: Fabrice Blain on November 20, 2001
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The Associated Press.
“Cool Weather Lessens E. coli Infections.” CNN.com, November 12, 2001.
United States Centers for Disease Control and
Prevention. Escherichia coli
Frequently Asked Questions. 14
November 2001 http://www.cdc.gov/ncidod/dbmd/diseaseinfo/escherichiacoli_g.htm.
Background: Escherichia coli O157:H7 is a Gram-negative rod-shaped bacterium. This serotype produces Shiga toxins in humans and may cause severe physical illness.
Definitions:
Hemolytic Uremic Syndrome – disease caused by E. coli that results in the destruction of red blood cells and kidney failure.
Summary: Scientists have found that between the months of October and May, E. coli infections are greatly decreased as compared to infections between the months of June and September. The most well supported theory for this phenomenon is that since temperatures drop during winter, it is more difficult for the E. coli bacterium to survive outside the cattle and be transmitted this time period. Government health officials suggest that the best way to end this problem is the treatment of animals in cattle feedlots.
Presented by: Maura V. Pannell on November 20, 2001
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Reitmeyer, John.
“Raccoon Tests Positive After Attacking Woman.” The
Burlington County Times (www.phillyburbs.com/burlingtoncountytimes),
October 30, 2001.
Background: Rabies is caused by a virus that is a member of the family Rhabdoviridae, viruses that contain a nonsegmented, negative-stranded RNA. The virus is composed of a helical ribonucleoprotein core and an envelope. Most reported cases of rabies are caused by wild animals, specifically raccoons, and are concentrated on the east coast of the United States, which is where the greatest population of raccoons is located. Rabies is spread mainly by saliva, which spreads from the nerves to the spinal cord and brain. Signs and symptons are not exhibited for 30-50 days. After symptoms are expressed, the individual or animal usually dies within 2-10 days. Human signs and symptoms include flu-like symptoms as well as increased saliva production, unusual sensitivity to light, anxiety, agitation, and paralysis. Rabies is confirmed by a dFA test. Treatment includes administering immunglobulin and a postexposure vaccine. [Center for Disease Control and Prevention] [National Institute of Allergy and Infectious Diseases ]
Definitions:
Negative-stranded RNA – RNA genome that is complementary to the mRNA; virions with negative-stranded RNA carry a virus-specific RNA polymerase necessary for snythesis of mRNA
dFA test – a test for rabies that uses labeled antibody that binds to the antigen and produces a bright apple green color when viewed using a fluorescence microscope
Summary: Burlington County Heath Officials are attempting to find a woman who was seen fending of a raccoon in Mount Laurel. The raccoon has been captured and tested positive for rabies. It needs to be determined whether she had physical contact with the raccoon because the disase is easily transmitted from an infected animal to a human by a bite, scratch, or contact with saliva. Rabies is treatable, but can be fatal if not treated.
Presented by: Leigh Anne Daniels on November 13, 2001
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Schogol, Marc.
"Abington student gets blood infection." The Philadelphia Inquirer November 7,
2001, p B7.
Background: Meningitis is an infection of the fluid of a person's cerebrospinal fluid. Two major types of bacterial meningitis are pneumococcal and meningococcal. This article is concerned only on the meningococcal bacterial meningitis. Caused by Neisseria meningitidis, a gram-negative diplococcus. This bacterium found naturally in the back of the nose and throat or upper respiratory tract of 10-25% of the general (healthy) population. These people are carriers and are asymptomatic. It is unclear what triggers the bacterium to move into the cerebrospinal fluid. Signs and symptoms include high fever, headache, stiff neck, and, in the case of meningococcemia, rash and sepsis. Meningococcemia is related to meningitis because both diseases are caused by the same bacterium. If untreated, meningococcemia will develop into meningitis. It is spread by close contact with sick individuals such as through kissing, sneezing and coughing. Antibiotics are available and effective if illness is caught early enough. A vaccine is available for multiple strains of N.meningitidis.
Definitions:
cerebrospinal fluid - a serous fluid secreted by the membranes covering the brain and spinal cord
sepsis - The presence of pathogenic organisms in the blood or tissues.
Summary: A 10th grade boy from Abington High School has been hospitalized with a meningitis-related blood disease. Four separate cases of the disease have been reported in the past year and a half in Abington School District and neighboring school districts. Three of these cases resulted in death. The school held a meeting with parents to inform them that the case was isolated and only students who had been in "close contact" with the boy should receive protective medication. Robert M. Burt, president of the school, stated that 200 of the school's 1,800 students fit this category. County health officials told the school on Monday afternoon that the 10th grader had meningococcemia, caused by Neisseria meningitidis. The student is expected to make a full recovery.
Presented by: Beth Dejewski on November 8, 2001
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Barboza, David, and Julian E.
Barnes. “Farmers and Processors
Act to Close Holes In Security.” The New York Times (www.nytimes.com),
October 28, 2001.
Background: There are a number of biological agents that have the potential to be used as weapons against the food and water systems in the United States. Foot-and-mouth disease and bovine spongiform encephalopathy are two biological agents that could have devastating effects on the livestock industry. Foot-and-mouth disease is caused by an aphthovirus, and causes pyrexia, vesicle formation in mouth and feet, and eventually lameness and death in sheep, cattle, and pigs. The virus is spread by direct contact with contaminated feces, animal products, or infected droplets. Bovine spongiform encephalopathy, or mad cow disease, is caused by a prion, and has caused neurological deterioration in almost 200,000 cattle in England who were fed feed contaminated with scrapie. It has now been found that humans are able to contract the disease as well by eating ground meat. Due to a ban on ruminant feed in the U.S. in 1997, there have been no problems thus far in the United States. A number of food borne toxins/bacteria have also been highlighted. The botulism toxin, produced in anaerobic environments (canned food), Staphylococcus aureus toxin, commonly produced in custards, hams, and poultry products, the epsilon toxin, produced most often in meat stews, Shigella dysenteriae, and Salmonella, have all been mentioned by the CDC and the U.S. Department of Health as potential biological warfare agents. (CDC website; Microbiology: An Introduction by G.J. Tortora, B.R. Funke, and C.L. Case, 7th edition, Menlo Park, CA: Benjamin/Cummings Publ. Co., 2000)
Definitions:
scrapie: prion associated with spongiform encephalopathy
toxin: poisonous substance produced by a microorganism.
Summary: Food security specialists and agriculture experts are calling for new measures to prevent biological or chemical contaminants from entering food storage facilities, packaged foods, or juices. The massive scale to which food is produced in the United States, and the fact that little to no bacterial testing is done to food just before it reaches the consumers makes the situation both difficult and frightening.
Presented by: Eileen Ford on November 6, 2001
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“Germs in meat stir debate on livestock drugs” CNN.com/Health,
October 18, 2001
Background:
Salmonella is a non-endospore forming, gram-negative bacterium that is characterized by a small rod shape. This bacterium is responsible for many cases of food-borne infection each year in the United States. All forms of Salmonella are pathogenic to some degree. (Microbiology: An Introduction by G.J. Tortora, B.R. Funke, and C.L. Case 7th edition, Menlo Park, CA: Benjamin/Cummings Publ. Co., 2001, chapter 11)
Summary: Studies demonstrated that one in five samples of supermarket meat and poultry were contaminated with salmonella. For decades, farmers have given antibiotics to animals raised for food. Over two million pounds of antibiotics go to sick animals. In addition antibiotics have traditionally been used to shield animals from disease and to promote competitive, healthy growth. This overuse of antibiotics has lead to the development of drug-resistant strains of bacteria. Many fear that due to this abuse of antibiotics, antibiotic resistant organisms could be spread to humans. For this reason, FDA officials are calling for stricter regulation on the use of antibiotics. Many believe that if antibiotics are used with the sole purpose of curing disease, and if handling conditions improve, then the threat of antimicrobial resistance could be avoided.
Presented by: Jeanine Cunningham on October 30, 2001
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Chang, Kenneth and Andrew Pollack. “Developing Warning System for Biological
Attack Proves Difficult.” The New York Times, October 28, 2001,
www.nytimes.com
Background:
Within the past couple weeks there has been a big threat of biological attack. There have been several anthrax scares and reported cases. As a result, the United States aims to speed the progress of developing technology to detect such attacks in a timely fashion.
Definitions:
Coliform- non-pathogenic,
mildly infective bacteria present in healthy animal intestines and taken in by
ingesting contaminated water; an increase in abundance of these might signify
the presence of more harmful intestinal pathogens such as Giardia and Crystosporidium
Giardia cysts- cystic bacteria carried in contaminated water; hatch in presence of stomach acids and attach to lining of intestines; cause fever, headache, abdominal cramps, diarrhea, nausea and vomiting
Crystosporidium parvum- protozoan with a complicated life cycle; they are carried in contaminated water and cause fever, headache, stomach cramps, diarrhea, nausea, vomiting, weight loss, and dehydration
Summary:
In anticipation of further bioterroristic attacks, the United States is attempting to upgrade technology and develop a sort of smoke detector for such attacks. Currently, systems are unable to differentiate between harmful and non-harmful germs. They also are costly and take a long time to identify possible pathogenic agents. New technology tracks microorganisms in real-time with a computer – organisms ranging from those that might be used biological attacks to those that cause mundane illnesses like the flu. Other developing technology has the ability to genetically test pathogens for identification.
Presented by: Amy Hartke on October 30, 2001
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Broad, William J. “ U.S. Acts to Make Vaccines and
Drugs Against Smallpox”. The New York Times, October 9, 2001, p. F1.
Background: The smallpox virus has killed more than 500 million people in the twentieth century. The disease is highly contagious by person-to-person contact, so an outbreak could cause a worldwide epidemic.
Definition:
Variola major - the virus that causes smallpox
Summary: As the threat of bioterrorism rises in the U.S., experts have been enlisted to increase the national stockpile of the smallpox vaccine. Researchers are doing so by diluting old vaccines, ordering the manufacture of a new vaccine, and looking into new antiviral drugs. While the chances of smallpox being used as a biological weapon are small, the government is taking no chances with what a possible outbreak could mean.
Presented by: Jennifer Bramble on October 25, 2001
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Associated
Press. “ Bubonic Plague kills 14 in
Uganda.” CNN.com,
October 11, 2001.
Background: Bubonic plague is a bacterial disease that is transmitted from
rodents to humans by fleas living on the infected animals. Humans can also get it through direct
contact with infected blood or tissues.
There are three different variations of the plague, including bubonic,
all of which are treatable with antibiotics if diagnosed in time. The symptoms are flu-like, including high
fever, chills, headache, muscle aches and sometimes vomiting. The
earliest known visitation of the plague to Europe occurred in Athens in 430
B.C. A disastrous epidemic occurred in
the Mediterranean during the time of the Roman emperor Justinian; an estimated
25% to 50% of the population is reported to have succumbed. The most widespread
epidemic began in Constantinople in 1334, spread throughout Europe (returning
Crusaders were a factor), and in less than 20 years is estimated to have killed
three quarters of the population of Europe and Asia. The great plague of London
in 1665 is recorded in many works of literature. Quarantine measures helped
contain the disease, but serious epidemics continued to occur even in the 19th
century. The disease is still prevalent in parts of Asia. In Surat, India, in
1994, 5,000 cases of pneumonic plague were reported in an outbreak; an
estimated 100 people died, and over 400,000 people fled the city. Because the
number of cases of plague has been increasing annually, the World Health
Organization categorizes it as a re-emerging infectious disease. (http://www.encyclopedia.com)
Definitions:
Plague- any
contagious, malignant, epidemic disease
Flea- a common
name for any of the small, wingless insects of the order Siphonaptera. The
adults of both sexes eat only blood and are all external parasites of mammals
and birds.
Summary: In Kampala, Uganda, there has been an
outbreak of bubonic plague that has killed 14 people in the last three weeks.
Government officials suggest that the disease is caused by an influx of rats
into several villages. The rats
normally live outside the villages but they seek shelter during the rainy
season. So far, 23 people have been infected with the disease, which affects
the lymph nodes, and 14 have died. No
new cases have been reported since October 3.
Presented by: Jamie Cifelli
on October 16, 2001
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Reuters Health.
“New Test May Accurately Detect Dormant TB: Study.” The Journal of the
American Medical Association, October 10, 2001, p.286
Background:
Tuberculosis(TB) is the common
name for the infection caused by the bacterium Mycobacterium tuberculosis.
TB can attack any part of the body, but the lungs are its most common
target. The usual signs of a TB
infection usually are a continuing cough, fevers, weight loss, night sweat,
constant tiredness, and loss of appetite.
Often people suppress this infection by building a wall around the
germs, like a scab over a cut. This
results in an infection that shows no signs, can not do bodily damage, or
spread to other people. However, active
TB results when the body can no longer contain the germs, and they begin to
proliferate in the body. This is often
the result of aging, illness, alcohol use, or a compromised immune system such
as an HIV-infected person. In addition,
tuberculosis is becoming increasingly resistant to antibiotic treatments, so
patients are now treated with a mixture of up to four different drugs to
prevent improved resistance. One
current method for detecting TB is a tuberculin PPD test, where a
non-infectious protein extract of TB is placed on the skin by a needle. A significant immune reaction indicates a
positive test for TB. Two other methods
are the chest x-ray, which evaluates the lungs for damage, and the sputum test
that examines the thick liquid a patient coughs up. This disease is most prevalent in developing nations with 95% of
the new TB cases coming from Africa, Asia, and parts of Latin America. This deadly infection has existed as far
back as ancient Egypt, and currently is responsible for up to 3 million deaths
per year. (http://www.umdnj.edu/~ntbcweb/history.htm)
Definitions:
Interferon-Gamma - an immune substance that is known to play a role in activating macrophages to function as effective phagocytic cells, with the phagocytosis of mycobacterial organisms providing the primary mechanism for eradicating the infection. (http://gcrc-www.med.nyu.edu/gcrc/research/ifn_gamma.html)
Macrophage-
a large cell that ingests material by
an engulfing process known as phagocytosis.
(http://gcrc-www.med.nyu.edu/gcrc/research/ifn_gamma.html)
Endemic- The constant presence of a disease or infectious agent within a given geographic area; may also refer to the usual prevalence of a given disease within such area.
(http://www.kumc.edu/instruction/medicine/pathology/ed/keywords/kw_endemic1.html)
Summary: In an attempt to prevent newer cases of active tuberculosis, the Centers for Disease Control and Prevention are now conducting a study that examines the efficacy of the interferon-gamma assay, a blood test for detecting TB. Currently the most common test used for TB detection is the tuberculin PPD test. This test however has its shortcomings. Skin tests often can give positive results for an infection caused by different bacteria, and previous vaccinations against TB often elicit the same response. This new blood test evaluates if the body is producing and releasing interferon gamma, an important immune response in fighting a mycobacterial infection. The new blood tests were better able to distinguish TB from other members of the same bacterial family, and gave more accurate readings from patients with previous vaccinations. Among the more than 1,200 US adults studied, the two TB tests were largely concordant, with their results agreeing in 83% of cases. After decades of decline, TB began a resurgence in the late 80s. This could be the result of more immigration from TB-endemic countries, more antibiotic resistant strains of TB, and the presence of HIV.
Presented by: Karl Smith on October 11, 2001
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Associated
Press. "Hawaii: 26 Confirmed
Dengue Fever Cases." CNN.com,
October 7, 2001.
Also, Associated
Press. "Dengue Fever Confirmed in
Hawaii." The Los Angeles Times, September 23, 2001, p. A42.
Background:
Dengue fever is a disease characterized by flu-like symptoms. It is caused by a single-stranded RNA virus that is transmitted primarily by the mosquito Aedes aegypti. One of four virus serotypes causes dengue fever. Each serotype is also capable of causing the more severe dengue hemorrhagic fever. If one serotype is contracted, you still have the ability to contract the other three serotypes in your lifetime. The first outbreak of dengue fever was reported in 1779. The disease is found in the tropics of the Americas, Asia, Africa, and Australia. Treatment of the disease includes fluids, rest, antipyretics, and monitoring. Currently there is no vaccine for dengue fever.
(Centers for Disease Control and Prevention -- Dengue Fever and Hawaii Department of Health)
Definitions:
Arbovirus - A mosquito-borne virus; short for arthropod-borne virus.
(from Microbiology: An Introduction by G.J. Tortora, B.R. Funke, and C.L. Case, 7th edition, Menlo Park, CA: Benjamin/Cummings Publ. Co., 2001, p. 615)
Serotype - A variation within a species; also called serovar.
(from Microbiology: An Introduction by G.J. Tortora, B.R. Funke, and C.L. Case, 7th edition, Menlo Park, CA: Benjamin/Cummings Publ. Co., 2001, p. 842)
Summary:
The Centers for Disease Control and Prevention have confirmed 26 cases of dengue fever in Hawaii. All of these confirmed cases have been on the island of Maui. There are over 100 suspected cases throughout the islands of Maui, Hawaii, Oahu, and Kauai. This is Hawaii's first outbreak of the mosquito-borne disease in over 50 years. The Hawaii State Health Director believes that the disease can be controlled since the outbreak was caught early. Crews will begin to dispose of trash that is a potential breeding site for the mosquitoes.
Presented by: Stacey Coryell on October 9, 2001
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Haney,
Daniel Q. "Early Interferon
treatment almost always cures hepatitis C." CNN.com
(http://cnn.health.printthis.clickabilit...519152&partnerID=2012&expire=10/15/2001),
October
1, 2001.
Background: Hepatitis C virus is an RNA virus surrounded
by a coat of proteins and an additional coat of lipids. There are at least six viruses known to
cause liver disease; however, hepatitis C is the most difficult for the immune
system to overcome. Most of the
infections become chronic and lead to liver disease. Early stages the infection are mild and are rarely recognized
(often exhibiting flu-like symptoms).
The entire cycle of the disease from infection to liver damage may take
as long as 20 years. Interferon A, made
by recombinant DNA techniques, was used to treat chronic liver disease. Interferon alpha is secreted naturally by
our cells in response to viral infection.
It binds to a membrane receptor and initiates a series of cellular
signaling events that eventually lead to the inhibition of virus replication in
infected cells.
(from Hepatitis
C web site).
Definitions:
Virion--a complete, fully developed, infectious
viral particle composed of nucleic acid and surrounded by a protein coat that
protects it from the environment and is a vehicle of transmission from one host
cell to another.
Nuclecapsid--the nucleic acid of
a virus surrounded by a protein coat.
Interferon alfa--a naturally
occurring glycoprotein that is secreted by cells in response to a viral
infection.
(from Microbiology: An Introduction by G.J. Tortora,
B.R. Funke, and C.L. Case, 7th edition, Menlo Park, CA:
Benjamin/Cummings Publ. Co., 2001, pp. 373-374 and http://hepatitis-central.com/hcv/ifn/toc.html).
Summary: According to a recent study lead by German
scientists, interferon A, can eliminate the hepatitis C virus; but the
injection of interferon A must be given soon after the earliest symptoms of the
viral disease appears. A study was performed
using 44 patients who carried the virus for 89 days. The patients received daily injections of interferon A for 4
weeks, then three times a week for 20 more weeks. About 48 weeks later, the virus was undetectable in 43
patients. Treatment can also be given
to people who have carried the virus for many years. Tt consists of a combination of interferon A and ribavirin. Such treatment eliminates virus half of the
time. Currently, about 4 million people
in the US are infected and 170 million worldwide. The infection became much less common when blood banks began
screening for the virus. Still,
hepatitis C infection is the leading cause of chronic liver disease in the US
and the most frequent reason for liver transplants.
Presented by: Olha Smolynets on October 4, 2001
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McClam, Erin.
“Iowa Wading Pool is linked to Illness.” Philadelphia Inquirer, September 21, 2001, p. A4.
Background: Bacteria of the species Shigella are transmitted via infected stool. These bacteria are facultatively anaerobic, gram-negative bacilli. Shigella are found where basic hygiene and hand washing habits are poor. The organism can be acquired by eating contaminated food or drinking or swimming in contaminated water. Shigellosis is the infectious disease caused by Shigella. The disease exhibits symptoms of bloody diarrhea, fever, and stomach cramps that typically last between five and seven days. S. sonnei is the most common species of Shigella in the U.S. Shigella reproduce in the small intestine, but damage the mucosa of the large intestine causing bloody diarrhea. Treatments include oral rehydration and antibiotics; however, due to increasing resistance, antibiotics are reserved for only the more severe cases of shigellosis.
Definition: Facultative anaerobe—an organism that can grow with or without molecular oxygen.
Summary: In mid-June, a recreational pool in Dubuque, Iowa, was closed after dozens of people who visited the pool were infected by shigella. Public health officials found that the pool had never been chlorinated. Since the pool was used primarily by small children, doctors believe that the outbreak occurred because an infected child wore a dirty diaper in the pool while others inadvertently ingested the nonchlorinated water. A total of 69 infections were reported, half of which were found in children six years old or younger.
PowerPoint Presentation
Additional information:
Centers for
Disease Control and Prevention (CDC) website
Presented by: Kate Loughery on October 2, 2001
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Associated Press.
“Ulcer germ tied to stomach cancer.”
Newsweek, September 12, 2001 http://www.msnbc.com/news/627975.asp
Background: Helicobacter pylori is a spiral shaped bacterium that lives in the stomach and duodenum. The organism is thought to be transmitted orally by means of fecal matter through the ingestion of waste-contaminated food or water. The germ imbeds itself in the mucus lining of the stomach to feed on the digested nutrients as well as to evade phagocytic lymphocyte cells (“About Helicobacter pylori.” Online. Internet. Available http://www.helico.com/newsite/aboutpylori.html.).
Definitions:
Cancer
- a malignant tumor whose cells have the properties
of endless replication, loss of contact inhibition, invasiveness and the
ability to metastasize and whose result, generally, if left untreated, is
fatal.
Summary: The Helicobacter
pylori bacterium is the cause of nearly all cases of stomach cancer around
the world. The bacterium is extremely
common and usually causes no symptoms.
In theUnited States approximately 30 to 40 percent of the population is
infected with the germ. In Japan, 1,526
people with ulcers and intestinal disorders were followed for a certain period
of time. Most of the people studied
were infected with H. pylori.
Stomach cancer ultimately developed in 2.9% of the infected people, but
not in the 280 uninfected patients nor the 253 who were treated to eliminate
the bacteria. For this reason, doctors
are suggesting that treating the bacteria with antibiotics would help prevent
tumors and eventually make stomach cancer a preventable disease.
Presented by: Yury Bak on September 27, 2001
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The second version of the first
examination will include “Microbiology in the News”
information presented through Sept. 20, 2001 only.
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Burns, Robert.
“Defense agency to create more potent anthrax strain.” The Philadelphia Inquirer, September
5, 2001, p. A4.
Background: The bacterium that causes anthrax in animals (Bacillus anthracis) was first isolated by Robert Koch in 1877. It is a large, aerobic, gram-positive microorganism, that is capable of growing in soil having specific moisture conditions. The bacteria primarily infect grazing animals such as cattle and sheep. Although the incidence in the U.S. of humans becoming infected with anthrax is now low, it is still possible to contract the disease. Transmission may occur by coming in contact with contaminated animals carrying the anthrax endospores, which can then enter the skin through cuts or abrasions, causing a pustule (see Figure 23.7, pg.631 in text). The most dangerous form of anthrax is pulmonary anthrax (Woolsorter’s disease), which occurs when the endospores are inhaled. Vaccination is available and it consists of six inoculations over 18 months, with annual boosters needed. Penicillin is the antibiotic of choice for treatment. Most horrific, however, is the use of anthrax as a biological weapon (Microbiology: An Introduction by G.J. Tortora, B.R. Funke, and C.L. Case, 7th edition, Menlo Park, CA: Benjamin/Cummings Publ. Co., 2001, pg. 631).
Definitions:
Vaccine- a preparation of killed, inactivated, or attenuated microorganisms or toxoids, which induce artificially, acquired, active immunity.
Biological weapon- a weapon containing diseases, germs, or other harmful organisms that can be used against persons, animals, and crops.
Summary: Currently, the Defense Agency is trying to develop a more potent variant of the bacterium that causes anthrax. This project is part of a broader research effort to improve U.S. defense against biological agents. The purpose of this new strain has been classified as strictly defensive in an effort to ensure that an effective vaccine is available should a biological weapon be used against American troops. This also protects the U.S. from any surprises, which may be contained in miniature bombs used to dispense these agents under different atmospheric conditions. There is a fear in the U.S. that such bombs are being sold on the international market.
Presented by: Jonathan Miller on September 20, 2001
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Kolata, Gina. "The Genesis of an Epidemic: Humans, Chimps and a Virus." The New York Times, Sept. 4, 2001, p. F1.
Background: AIDS has become an epidemic not only here in the United States,
but around the world as well. If
researchers can figure out exactly where and how this virus originated, it may
possibly lead to discovering a cure someday.
Definitions: HIV-1 virus - the virus that causes AIDS in humans
Summary: Dr. Beatrice Hahn discovered a virus in the tissues of a frozen
chimpanzee that looked like HIV-1.
This, coupled with other evidence of a similar virus found in other
chimpanzees, has led researchers to believe that the disease was transmitted to
humans in west central Africa by chimpanzees.
One line of evidence points at west central Africa because there are
numerous "types" of HIV virus in this area. The more diverse an organism’s genes are, the longer it has been
around.
Presented by: Melissa Genovese on September 18, 2001
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Burling, Stacey and Vigoda, Ralph. “Penguin killed by West Nile, zoo
officials say.” Philadelphia
Inquirer, September 11, 2001: http://web.realcities.com/content/rc/health/pchealth/philly/
Background: West Nile virus has emerged in recent years in temperate regions of Europe and North America, presenting a threat to public, equine, and animal health. Transmitted by mosquitoes, the West Nile virus causes encephalitis in humans and horses as well as mortality in domestic and wildlife birds.
Definition:
Encephalitis - inflammation of the brain that interferes with the normal central nervous system functioning
Summary: A 13-year-old female penguin at the Philadelphia Zoo was killed by West Nile virus last week. A week prior to this a flamingo also died of the same cause. Mosquitoes are transmitting this deadly virus. The distressing symptoms of the two birds were as follows: the activity level of the birds drastically dropped as well as their desire to eat. West Nile usually affects birds, mostly crows, but there are other incidents in which two horses contracted the disease. Humans can also become infected by mosquitoes carrying the virus. For the last three summers 10 people in New York City have died. Infected people might only have mild, flu-like symptoms or more serious symptoms such as high fever, severe headaches, body aches, and stiff necks.
As of today, another 18-year-old male penguin has fallen victim to the virus.
Presented by: Thanh Dang a.k.a. Jackie on September 13, 2001
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Astill, James.
“Plague Kills 2M People A Year.”
The Guardian Newspapers Limited, September 3, 2001, p. 3.
Background: Malaria is a parasite carried in the salivary glands of the female mosquito. When a female mosquito carrying the parasite bites a human the parasite is transmitted to that person. On the other hand, when an uninfected female mosquito bites an infected human, the female mosquito will pick up the parasite and possibly infect another human.
Definition:
Parasite - an organism that derives nutrients from a living host (Naik, Gautum. “Deadly Mutant Strain of Malaria Appears to Have Reached Africa.” Wall Street Journal, July 26, 2001, p. B1.).
Summary: Second only to AIDS, malaria kills 2 million people per year while infecting another 500 million per year. Africa is the hardest hit continent because it is home to the most deadly of four strains of malaria, Plasmodium falciparum. Plasmodium falciparum destroys red blood cells and has the potential to kill a person within twenty-four hours if the parasite enters the brain.
For years, poverty stricken Africa has used an economical drug called quinine in order to cure malaria patients. Because of the parasite’s ability to genetically mutate, this drug is now 80% ineffective. A new Chinese herb has been used with great success to cure malaria; however, this herb is more costly, and the western world sees little advantage in bringing its market to a continent that has little money to offer.
Presented by: Mike Palladino on September 6, 2001
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Associated Press.
“Researchers’ Images of Prions May Illuminate Rogue Protein’s Role in
‘Mad Cow’ Disease.” Post Gazette,
September 3, 2001, p.1.
Background: Mad cow disease or bovine spongiform encephalopathy (BSE) was discovered by microbiologists in 1986 as a disease caused by an infectious protein called a prion. The disease causes large vacuoles to develop in the brain. (Microbiology: An Introduction by G.J. Tortora, B.R. Funke, and C.L. Case, 7th edition, Menlo Park CA: Benjamin/Cummings Publ. Co., 2001 chapter 1 and 13)
Definitions:
Prion – An infectious agent consisting of a self-replicating protein, with no detectable nucleic acids.
Summary: At one time researchers believed that prions (infectious proteins) acted as monomers. Recently researchers have developed images of prions interacting with each other. This evidence supports the hypothesis that prions are related to normal cellular proteins. This hypothesis suggests that when a prion with an abnormal configuration infects a cell it is able to bind to the related normal prion-like proteins already present in the cell and change their configuration. Somehow proteins in this abnormal configuration initiate pathogenesis. This pathogenesis can lead to “mad cow”, Creutzfeld-Jakob disease (CJD), and other neurodegenerative diseases.
Evidence for these prion-prion interactions could help researchers to develop ways to detect the beginnings of prion-related diseases and produce drugs to impede the pairings.
Presented by: Mike Wasco on September 11, 2001
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