Lyme disease in the U.S. is caused by a form of bacteria, the spirochete Borrelia burgdorferi, infecting humans by tick bites. It typically begins with a bull's-eye skin rash, accompanied by fever, muscle aches, or other flu-like symptoms. If diagnosed early, Lyme can be treated successfully within a month with either oral or intravenous antibiotics. Nearly 60 percent of patients who do not receive antibiotic therapy early in the illness develop intermittent or persistent arthritis, particularly affecting the knees. Moreover, a small percentage of Lyme patients who do receive antibiotic therapy suffer from persistent arthritis for months or even several years after 2-3 months of oral and intravenous antibiotic therapy. This confounding condition has been termed antibiotic-refractory, or slowly resolving, Lyme arthritis.
To gain insights into the survival of spirochetes following antibiotic therapy, researchers at the Center for Immunology and Inflammatory Diseases at Massachusetts General Hospital, Harvard Medical School, and the National Center for Infectious Diseases at the Centers for Disease Control and Prevention teamed up to study antibody responses to Borrelia burgdorferi in patients with antibiotic-refractory or antibiotic-responsive Lyme arthritis. Presented in the December 2007 issue of Arthritis & Rheumatism , their findings indicate that joint inflammation persists in patients with antibiotic-refractory Lyme arthritis after the disease-spreading spirochetes have been killed.
To compare antibody responses and determine their effect on Lyme arthritis, the team tested at least 3 blood serum samples each from 41 patients with antibiotic-refractory arthritis, 23 patients with antibiotic-responsive arthritis, and 10 non-antibiotic-treated controls - arthritis patients who had contracted Lyme disease during the late 1970s before the cause of the disease was known. Samples were obtained during the period of arthritis and sometimes after several months of remission for all patient groups. The patients with antibiotic-refractory and antibiotic-responsive arthritis had a similar age range, sex distribution, and duration of arthritis prior to antibiotic therapy.
All samples were tested for IgG reactivity with Borrelia burgdorferi bacteria and 4 outer surface lipoproteins of the spirochete. Among non-antibiotic-treated patients, antibody titers to Borrelia burgdorferi remained high throughout a prolonged period of persistent arthritis, 2 to 5 years. In contrast, in patients with antibiotic-responsive arthritis, the level of antibody titers to Borrelia burgdorferi and most outer-surface proteins remained steady or decreased within the first 3 months of starting antibiotic therapy. Consistent with this finding, these patients usually experienced relief from joint swelling during a 1-month course of oral antibiotics. In patients afflicted with antibiotic-refractory arthritis, the level of antibody titers to Borrelia burgdorferi and most outer-surface antigens increased slightly during the first 1 to 3 months of treatment. These patients suffered from persistent joint swelling for a median duration of 10 months, despite 2 to 3 months of oral or intravenous antibiotics. However, by 4 to 6 months after starting antibiotic therapy, antibody titers declined to similar levels in both antibiotic-treated groups, regardless of their differences in arthritis symptoms.
"In Lyme disease, there is a great need for a test that could be used in clinical practice as a marker for spirochetal eradication," observes Dr. Allen C. Steere, the senior author of the study. Yet, as he acknowledges, ridding the body of the Borrelia burgdorferi bacteria and its surface antigens does not always bring relief from arthritis. "Increasing antibody titers in patients usually suggested the presence of live spirochetes, whereas declining titers suggested that they had been killed," he notes. "Thus, patients with Lyme arthritis who have a sustained, gradual decline in antibody reactivity probably have the nearly complete or total eradication of spirochetes from the joint as a result of antibiotic therapy, even if joint inflammation persists after the period of infection."
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Article adapted by Medical News Today from original press release.
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Article: "Antibody Responses to Borrelia burgdorferi in Patients With Antiobiotic-Refractory, Antibiotic-Responsive, or Non-Antibiotic-Treated Lyme Disease," Priya Kannian, Gail McHugh, Barbara J.B. Johnson, Rendi M. Bacon, Lisa J. Glickstein, and Allen C. Steere, Arthritis & Rheumatism, December 2007.
Source: Amy Molnar
Wiley-Blackwell
Showing posts with label bacteria. Show all posts
Showing posts with label bacteria. Show all posts
Friday, December 14, 2007
Saturday, June 16, 2007
Study Finds Pomegranate Effective In Fighting Bacteria, Viruses
A Pace University Study has found that pure pomegranate juice and pomegranate liquid extract are effective in fighting viruses and bacteria. According to their findings, 100% Pomegranate juice and POMx liquid extract could significantly reduce microbes found in the mouth that commonly cause cavities, staph infections and food poisoning
If the answer to improved health through protection against common germs and pathogens was as simple as drinking pomegranate juice, it seems everyone would be a lot healthier.
Recent preliminary research by Milton Schiffenbauer, Ph.D., a biology professor at Pace University in New York, indicates it just might be that simple. The research revealed that 100% pomegranate juice and POMx liquid extract (pomegranate polyphenol extract), made from the Wonderful variety of pomegranate grown in California, have antiviral and antibiotic effects. His findings will be introduced May 22 at the American Society for Microbiology's annual meeting in Toronto in a presentation entitled: "The Inactivation of Virus and Destruction of Bacteria by Pomegranate Juice."
In this exploratory study, Schiffenbauer tested 100% pomegranate juice and POMx liquid extract and the effect each had on a bacterial virus T1 and several bacteria over various periods of time, in various conditions and with the addition of other ingredients. The titer of T1 virus,(a model system) which infects E.coli B decreased up to 100% within 10 minutes of the addition of 100% pomegranate juice or POMx liquid extract. The research was funded by Pace University and POM Wonderful LLC and was conducted using POM Wonderful pomegranate products.
Both were also found to be effective in the destruction of bacteria S. mutans, known to cause cavities, S. aureus, the most common cause of staph infections, and B. cereus, a common cause of food poisoning. Schiffenbauer's findings also indicate that 100% pomegranate juice and POMx liquid extract inhibit the spread of Methicillin-resistant Staphylococcus aureus (MRSA), having widespread implications in the treatment of these potentially pathogenic microorganisms.
The addition of the POM products to various oral agents, including toothpaste and mouthwash, gave these agents an antimicrobial effect.
This work comes on the heels of earlier studies conducted by Schiffenbauer that found that white tea and green tea extracts also have antimicrobial effects. According to Schiffenbauer, pomegranate has gotten even better results than the teas.
Source: postchronicle.com
If the answer to improved health through protection against common germs and pathogens was as simple as drinking pomegranate juice, it seems everyone would be a lot healthier.
Recent preliminary research by Milton Schiffenbauer, Ph.D., a biology professor at Pace University in New York, indicates it just might be that simple. The research revealed that 100% pomegranate juice and POMx liquid extract (pomegranate polyphenol extract), made from the Wonderful variety of pomegranate grown in California, have antiviral and antibiotic effects. His findings will be introduced May 22 at the American Society for Microbiology's annual meeting in Toronto in a presentation entitled: "The Inactivation of Virus and Destruction of Bacteria by Pomegranate Juice."
In this exploratory study, Schiffenbauer tested 100% pomegranate juice and POMx liquid extract and the effect each had on a bacterial virus T1 and several bacteria over various periods of time, in various conditions and with the addition of other ingredients. The titer of T1 virus,(a model system) which infects E.coli B decreased up to 100% within 10 minutes of the addition of 100% pomegranate juice or POMx liquid extract. The research was funded by Pace University and POM Wonderful LLC and was conducted using POM Wonderful pomegranate products.
Both were also found to be effective in the destruction of bacteria S. mutans, known to cause cavities, S. aureus, the most common cause of staph infections, and B. cereus, a common cause of food poisoning. Schiffenbauer's findings also indicate that 100% pomegranate juice and POMx liquid extract inhibit the spread of Methicillin-resistant Staphylococcus aureus (MRSA), having widespread implications in the treatment of these potentially pathogenic microorganisms.
The addition of the POM products to various oral agents, including toothpaste and mouthwash, gave these agents an antimicrobial effect.
This work comes on the heels of earlier studies conducted by Schiffenbauer that found that white tea and green tea extracts also have antimicrobial effects. According to Schiffenbauer, pomegranate has gotten even better results than the teas.
Source: postchronicle.com
Saturday, June 9, 2007
Evolution at Work: Watching Bacteria Grow Drug Resistant
Day by day, the doctors unwittingly helped the bacteria infecting their young heart patient to evolve. The more intensively they treated his affliction with antibiotics, the more the microbes resisted the therapy.
In a strict medical sense, the young man, identified only as Patient X, died of complications from a congenital heart ailment and a Staphylococcus aureus infection.
More broadly, evolution killed him.
The life-and-death struggle inside his infected heart was driven by the same evolutionary forces of natural selection and adaptation that are causing a pandemic of drug-resistant diseases world-wide. The emergence of such immunity among infectious diseases is one of the most well-documented problems in modern public health. Until now, however, researchers knew little about how bacteria multiplying inside the human body overcome the drugs designed to control them.
Patient X died in October 2000 after a 12-week hospital stay. His case comes to light now because researchers only recently developed the computational techniques needed to sequence generations of bacteria. The hospital, which also wasn't identified, gave the patient's Staph samples to the Rockefeller team for research purposes. The techniques still are too slow and expensive for clinical use.
When Patient X was admitted to the hospital, he was already suffering from a Staphylococcus aureus infection, but it was still vulnerable to antibiotics. During treatment, however, the bacteria quickly developed stronger resistance to four antibiotics, including vancomycin, the drug of last resort for intractable infections, the scientists reported. As living bacteria, the Staph were driven to survive.
Every time the patient took his medicine, the antibiotics killed the weakest bacteria in his bloodstream. Any cell that had developed a protective mutation to defend itself against the drug survived, passing on its special trait to descendants. With every round of treatment, the cells refined their defenses through the trial and error of survival. "It means that during a normal course of treatment there is an evolutionary revolution going on in your body," said Stanford University biologist Stephen Plaumbi, author of "The Evolution Explosion: How Humans Cause Rapid Evolutionary Change."
These resistant microbes, all disease-producing organisms spawned by the original infection, quickly accumulated 35 useful mutations. Each one altered a molecular sensor or production of a protein.
Researchers then matched these gradual genetic changes to increasing levels of drug resistance, shocked that it took so little to undermine the foundation of modern infectious-disease control. "We have now really looked into the belly of the beast and seen the mechanism," said Rockefeller microbiologist Alexander Tomasz.
Nearly two million people catch bacterial infections in U.S. hospitals every year and 90,000 of them die -- seven times as high as a decade ago as germs become immune to almost every antibiotic developed during the past 60 years. The most common is the Staphylococcus bacteria. World-wide, some two billion people carry these bacteria; up to 53 million people are thought to harbor antibiotic-resistant forms.
On average, people who contract Staph infections stay in the hospital three times as long and face five times the risk of dying. But these infections are becoming more prevalent outside hospitals. Antibiotic-resistant Staph infections increased almost sevenfold from 2001 to 2005, researchers reported last week in the Archives of Internal Medicine. Contagions such as tuberculosis, pneumonia and bubonic plague also are becoming immune to the drugs that once kept them at bay.
The death of Patient X highlights the speed of natural selection in fostering antibiotic resistance. "When you talk about the evolution of an arm or an eye or a species, you might be talking about millions of years. You can get bacteria resistant in a week," Dr. Mwangi said.
The Rockefeller researchers believe that a better understanding of evolution will lead to better antibiotic treatments. They want to disable the genes that allow these disease bacteria to mutate and adapt. The Staph bacteria that evolved inside Patient X now have such strong defenses that, in recent tests, they easily withstood even the next generation of clinical antibiotics. For the time being, the microbes are keeping one step ahead.
In a strict medical sense, the young man, identified only as Patient X, died of complications from a congenital heart ailment and a Staphylococcus aureus infection.
More broadly, evolution killed him.
The life-and-death struggle inside his infected heart was driven by the same evolutionary forces of natural selection and adaptation that are causing a pandemic of drug-resistant diseases world-wide. The emergence of such immunity among infectious diseases is one of the most well-documented problems in modern public health. Until now, however, researchers knew little about how bacteria multiplying inside the human body overcome the drugs designed to control them.
Patient X died in October 2000 after a 12-week hospital stay. His case comes to light now because researchers only recently developed the computational techniques needed to sequence generations of bacteria. The hospital, which also wasn't identified, gave the patient's Staph samples to the Rockefeller team for research purposes. The techniques still are too slow and expensive for clinical use.
When Patient X was admitted to the hospital, he was already suffering from a Staphylococcus aureus infection, but it was still vulnerable to antibiotics. During treatment, however, the bacteria quickly developed stronger resistance to four antibiotics, including vancomycin, the drug of last resort for intractable infections, the scientists reported. As living bacteria, the Staph were driven to survive.
Every time the patient took his medicine, the antibiotics killed the weakest bacteria in his bloodstream. Any cell that had developed a protective mutation to defend itself against the drug survived, passing on its special trait to descendants. With every round of treatment, the cells refined their defenses through the trial and error of survival. "It means that during a normal course of treatment there is an evolutionary revolution going on in your body," said Stanford University biologist Stephen Plaumbi, author of "The Evolution Explosion: How Humans Cause Rapid Evolutionary Change."
These resistant microbes, all disease-producing organisms spawned by the original infection, quickly accumulated 35 useful mutations. Each one altered a molecular sensor or production of a protein.
Researchers then matched these gradual genetic changes to increasing levels of drug resistance, shocked that it took so little to undermine the foundation of modern infectious-disease control. "We have now really looked into the belly of the beast and seen the mechanism," said Rockefeller microbiologist Alexander Tomasz.
Nearly two million people catch bacterial infections in U.S. hospitals every year and 90,000 of them die -- seven times as high as a decade ago as germs become immune to almost every antibiotic developed during the past 60 years. The most common is the Staphylococcus bacteria. World-wide, some two billion people carry these bacteria; up to 53 million people are thought to harbor antibiotic-resistant forms.
On average, people who contract Staph infections stay in the hospital three times as long and face five times the risk of dying. But these infections are becoming more prevalent outside hospitals. Antibiotic-resistant Staph infections increased almost sevenfold from 2001 to 2005, researchers reported last week in the Archives of Internal Medicine. Contagions such as tuberculosis, pneumonia and bubonic plague also are becoming immune to the drugs that once kept them at bay.
The death of Patient X highlights the speed of natural selection in fostering antibiotic resistance. "When you talk about the evolution of an arm or an eye or a species, you might be talking about millions of years. You can get bacteria resistant in a week," Dr. Mwangi said.
The Rockefeller researchers believe that a better understanding of evolution will lead to better antibiotic treatments. They want to disable the genes that allow these disease bacteria to mutate and adapt. The Staph bacteria that evolved inside Patient X now have such strong defenses that, in recent tests, they easily withstood even the next generation of clinical antibiotics. For the time being, the microbes are keeping one step ahead.
Saturday, May 5, 2007
New Approach Could Lower Antibiotic Requirements By 50 Times
Antibiotic doses could be reduced by up to 50 times using a new approach based on bacteriophages.
Steven Hagens, previously at the University of Vienna, told Chemistry & Industry, the magazine of the SCI, that certain bacteriophages, a type of virus that infects bacteria, can boost the effectiveness of antibiotics gentamicin, gramacidin or tetracycline.
It is the phages' ability to channel through bacterial cell membranes that boosts antibiotic effectiveness. 'Pseudomonas bacteria for example are particularly multi-resistant to antibiotics because they have efflux pump mechanisms that enable them to throw out antibiotics. A pore in the cell wall would obviously cancel the efflux effect,' Hagens explains.
Pseudomonas bacteria cause pneumonia and are a common cause of hospital-acquired infections.
Experiments in mice revealed that 75% of those infected with a lethal dose of Pseudomonas survived if the antibiotic gentamicin was administered in the presence of bacteriophages. None survived without the phages (Microb. Drug Resist., 2006, 12 (3), 164).
The bacteriophage approach would also be particularly useful for treating cases of food poisoning, because the lower doses of antibiotic needed would not disrupt the friendly bacteria in the gut - a big problem with conventional antibiotic treatments.
'The prospect of using such treatments to prolong the life of existing agents and delay the onset of widespread resistance is to be welcomed,' said Jim Spencer a lecturer in microbial pathogenesis at the University of Bristol.
The overuse of antibiotics since the 1940s had slowly created a host of infections that are resistant to antibiotics. MRSA (Methicillin-resistant Staphylococcus aureus) for example is rapidly spreading through hospitals, affecting more than 8,000 people in the UK every year. MRSA infection can lead to septic shock and death.
Note: This story has been adapted from a news release issued by Society of Chemical Industry.
Steven Hagens, previously at the University of Vienna, told Chemistry & Industry, the magazine of the SCI, that certain bacteriophages, a type of virus that infects bacteria, can boost the effectiveness of antibiotics gentamicin, gramacidin or tetracycline.
It is the phages' ability to channel through bacterial cell membranes that boosts antibiotic effectiveness. 'Pseudomonas bacteria for example are particularly multi-resistant to antibiotics because they have efflux pump mechanisms that enable them to throw out antibiotics. A pore in the cell wall would obviously cancel the efflux effect,' Hagens explains.
Pseudomonas bacteria cause pneumonia and are a common cause of hospital-acquired infections.
Experiments in mice revealed that 75% of those infected with a lethal dose of Pseudomonas survived if the antibiotic gentamicin was administered in the presence of bacteriophages. None survived without the phages (Microb. Drug Resist., 2006, 12 (3), 164).
The bacteriophage approach would also be particularly useful for treating cases of food poisoning, because the lower doses of antibiotic needed would not disrupt the friendly bacteria in the gut - a big problem with conventional antibiotic treatments.
'The prospect of using such treatments to prolong the life of existing agents and delay the onset of widespread resistance is to be welcomed,' said Jim Spencer a lecturer in microbial pathogenesis at the University of Bristol.
The overuse of antibiotics since the 1940s had slowly created a host of infections that are resistant to antibiotics. MRSA (Methicillin-resistant Staphylococcus aureus) for example is rapidly spreading through hospitals, affecting more than 8,000 people in the UK every year. MRSA infection can lead to septic shock and death.
Note: This story has been adapted from a news release issued by Society of Chemical Industry.
Germs: Understand and protect against bacteria, viruses and infection
You live in a world of germs. Some keep you healthy — others make you sick. Protect yourself by understanding which ones are harmless and which ones pose a threat.
Germs were behind every fever, runny nose, ache, pain and other sign and symptom of every cold and flu you've ever had. When you're in the midst of such symptoms, you might not stop to think about the germs (microbes) that are causing them. Not all germs will harm you, but knowing more about germs — including bacteria, viruses and parasites — can increase your chances of avoiding infection.
Germs: A multitude of microscopic invaders
Bacteria, viruses and other infectious organisms — germs — live everywhere. You can find them in the air, on food, plants and animals, in the soil, in the water, and on just about every other surface — including your own body. These microbes range in size from microscopic single-celled organisms to parasitic worms that can grow to several feet in length.
Most of these organisms won't harm you. Your immune system protects you against a multitude of infectious agents. However, some bacteria and viruses are formidable adversaries because they're constantly mutating to breach your immune system's defenses.
E. coli O157:H7 is a bacterium responsible for food-borne infections often linked to eating undercooked ground beef or improperly washed vegetables.
BacteriaBacteria are one-celled organisms visible only with a microscope. They're so small that if you lined up a thousand of them end to end, they could fit across the end of a pencil eraser. They're shaped like short rods, spheres or spirals. Bacteria are self-sufficient — they don't need a host to reproduce and they multiply by subdivision.
Among the earliest forms of life on earth, bacteria have evolved to thrive in a variety of environments. Some can withstand searing heat or frigid cold, and others can survive radiation levels that would be lethal to humans. Many bacteria, however, prefer the mild environment of a healthy body.
Not all bacteria are harmful. In fact, less than 1 percent cause disease, and some bacteria that live in your body are actually good for you. For instance, Lactobacillus acidophilus — a harmless bacterium that resides in your intestines — helps you digest food, destroys some disease-causing organisms and provides nutrients to your body.
But when infectious bacteria enter your body, they can cause illness. They rapidly reproduce, and many produce toxins — powerful chemicals that damage specific cells in the tissue they've invaded. That's what makes you ill. The organism that causes gonorrhea (gonococcus) is an example of a bacterial invader. Others include some strains of the bacterium Escherichia coli — better known as E. coli — which cause severe gastrointestinal illness and are most often contracted via contaminated food. If you've ever had strep throat, bacteria caused it.
The influenza virus takes over healthy cells, spreads through your body and causes illness. Signs and symptoms include fever, chills, muscle aches and fatigue.
VirusesIn its simplest form, a virus is a capsule that contains genetic material — DNA or RNA. Viruses are even tinier than bacteria. To put their size into perspective, consider that, according to the American Society for Microbiology, if you were to enlarge an average virus to the size of a baseball, the average bacterium would be about the size of the pitcher's mound. And just one of your body's millions of cells would be the size of the entire ballpark.
The main mission of a virus is to reproduce. However, unlike bacteria, viruses aren't self-sufficient — they need a suitable host to reproduce. When a virus invades your body, it enters some of your cells and takes over, instructing these host cells to make what it needs for reproduction. Host cells are eventually destroyed during this process. Polio, AIDS and the common cold are all viral illnesses.
Infection with candida fungus can lead to problems such as diaper rash, vaginal yeast infections and oral thrush.
FungiMolds, yeasts and mushrooms are types of fungi. For the most part, these single-celled organisms are slightly larger than bacteria, although some mushrooms are multicelled and plainly visible to the eye. Mushrooms can't infect you, but certain yeasts and molds can.
Fungi live in the air, water, soil and on plants. They can live in your body, usually without causing illness. Some fungi have beneficial uses. For example, penicillin — an antibiotic that kills harmful bacteria in your body — is derived from fungi. Fungi are also essential in making certain foods, such as bread, cheese and yogurt.
Other fungi aren't as beneficial and can cause illness. One example is candida — a yeast that can cause infection. Candida can cause thrush — an infection of the mouth and throat — in infants and in people taking antibiotics or who have an impaired immune system. It's also responsible for most types of infection-related diaper rash.
Cryptosporidium is a protozoan that can survive outside the body for long periods of time.
ProtozoaProtozoa are single-celled organisms that behave like tiny animals — hunting and gathering other microbes for food. Protozoa can live within your body as a parasite. Many protozoa call your intestinal tract home and are harmless. Others cause disease, such as the 1993 Cryptosporidium parvum invasion of the Milwaukee water supply, sickening more than 400,000 people. Often, these organisms spend part of their life cycle outside of humans or other hosts, living in food, soil, water or insects.
Most protozoa are microscopic, but there are some exceptions. One type of ocean-dwelling protozoa (foraminifer) can grow to more than 2 inches in diameter.
Some protozoa invade your body through the food you eat or the water you drink. Others can be transmitted through sexual contact. Still others are vector-borne, meaning they rely on another organism to transmit them from person to person. Malaria is an example of a disease caused by a vector-borne protozoan parasite. Mosquitoes are the vector transmitting the deadly parasite plasmodium, which causes the disease.
Infection by one type of roundworm, known as a hookworm, can cause problems in your small intestine or lungs. The average hookworm is about half an inch long.
HelminthsHelminths are among the larger parasites. The word "helminth" comes from the Greek for "worm." If this parasite — or its eggs — enters your body, it takes up residence in your intestinal tract, lungs, liver, skin or brain, where it lives off the nutrients in your body. The most common helminths are tapeworms and roundworms.
The largest of the roundworms can be more than 12 inches long. And the largest of the tapeworms can grow to be 25 feet or longer. Tapeworms are made up of hundreds of segments, each of which is capable of breaking off and developing into a new tapeworm.
Understanding infection vs. disease
There's a distinct difference between infection and disease. Infection, often the first step, occurs when bacteria, viruses or other microbes enter your body and begin to multiply. Disease occurs when the cells in your body are damaged — as a result of the infection — and signs and symptoms of an illness appear.
In response to infection, your immune system springs into action. An army of white blood cells, antibodies and other mechanisms goes to work to rid your body of whatever is causing the infection. For instance, in fighting off the common cold, your body might react with fever, coughing and sneezing.
Warding off germs and infection
What's the best way to stay disease-free? Prevent infections from happening in the first place. You can prevent infection through simple tactics such as regular hand washing, vaccinations and appropriate medications.
Hand washing. Often overlooked, hand washing is one of the easiest and most effective ways to protect yourself from germs and most infections. Wash your hands thoroughly before preparing or eating food, after coughing or sneezing, after changing a diaper and after using the toilet. When soap and water aren't readily available, alcohol-based hand-sanitizing gels can offer protection.
Vaccines. Vaccination is your best line of defense for certain diseases. As researchers understand more about what causes disease, the list of vaccine-preventable diseases continues to grow. Many vaccines are given in childhood, but adults still need to be routinely vaccinated to prevent some illnesses, such as tetanus and influenza.
Medicines. Some medicines can help you from becoming susceptible to germs. For example, taking an anti-parasitic medication might protect you from contracting malaria if you travel to or live in an area where your risk is high. Or when you are at high risk of exposure to certain organisms — such as those that cause bacterial meningitis — your doctor may prescribe antibiotics to lower your risk of infection. Using over-the-counter antibiotic creams can decrease the chance of infection of minor cuts and scrapes. But long-term, indiscriminate use of antibiotics isn't recommended in most cases. It won't prevent bacterial infections and instead may result in a more resistant, harder-to-treat strain of bacteria when infections do occur.
When to seek medical care
Although some infectious diseases, such as the common cold, might not require a visit to the doctor, others might.
Seek medical care if you suspect that you have an infection and you have experienced any of the following:
An animal or human bite
Difficulty breathing
A cough lasting longer than a week
A fever of 100.4 F (38.0 C) or more
Periods of rapid heartbeat
A rash, especially if it's accompanied by a fever
Swelling
Blurred vision or other difficulty seeing
Persistent vomiting
An unusual or severe headache
Your doctor can perform diagnostic tests to find out if you're infected, the seriousness of the infection, and how best to treat that infection.
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Viral infections and bacterial infections: What's the difference?
Are infectious diseases on the rise? Editor's note
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Germs were behind every fever, runny nose, ache, pain and other sign and symptom of every cold and flu you've ever had. When you're in the midst of such symptoms, you might not stop to think about the germs (microbes) that are causing them. Not all germs will harm you, but knowing more about germs — including bacteria, viruses and parasites — can increase your chances of avoiding infection.
Germs: A multitude of microscopic invaders
Bacteria, viruses and other infectious organisms — germs — live everywhere. You can find them in the air, on food, plants and animals, in the soil, in the water, and on just about every other surface — including your own body. These microbes range in size from microscopic single-celled organisms to parasitic worms that can grow to several feet in length.
Most of these organisms won't harm you. Your immune system protects you against a multitude of infectious agents. However, some bacteria and viruses are formidable adversaries because they're constantly mutating to breach your immune system's defenses.
E. coli O157:H7 is a bacterium responsible for food-borne infections often linked to eating undercooked ground beef or improperly washed vegetables.
BacteriaBacteria are one-celled organisms visible only with a microscope. They're so small that if you lined up a thousand of them end to end, they could fit across the end of a pencil eraser. They're shaped like short rods, spheres or spirals. Bacteria are self-sufficient — they don't need a host to reproduce and they multiply by subdivision.
Among the earliest forms of life on earth, bacteria have evolved to thrive in a variety of environments. Some can withstand searing heat or frigid cold, and others can survive radiation levels that would be lethal to humans. Many bacteria, however, prefer the mild environment of a healthy body.
Not all bacteria are harmful. In fact, less than 1 percent cause disease, and some bacteria that live in your body are actually good for you. For instance, Lactobacillus acidophilus — a harmless bacterium that resides in your intestines — helps you digest food, destroys some disease-causing organisms and provides nutrients to your body.
But when infectious bacteria enter your body, they can cause illness. They rapidly reproduce, and many produce toxins — powerful chemicals that damage specific cells in the tissue they've invaded. That's what makes you ill. The organism that causes gonorrhea (gonococcus) is an example of a bacterial invader. Others include some strains of the bacterium Escherichia coli — better known as E. coli — which cause severe gastrointestinal illness and are most often contracted via contaminated food. If you've ever had strep throat, bacteria caused it.
The influenza virus takes over healthy cells, spreads through your body and causes illness. Signs and symptoms include fever, chills, muscle aches and fatigue.
VirusesIn its simplest form, a virus is a capsule that contains genetic material — DNA or RNA. Viruses are even tinier than bacteria. To put their size into perspective, consider that, according to the American Society for Microbiology, if you were to enlarge an average virus to the size of a baseball, the average bacterium would be about the size of the pitcher's mound. And just one of your body's millions of cells would be the size of the entire ballpark.
The main mission of a virus is to reproduce. However, unlike bacteria, viruses aren't self-sufficient — they need a suitable host to reproduce. When a virus invades your body, it enters some of your cells and takes over, instructing these host cells to make what it needs for reproduction. Host cells are eventually destroyed during this process. Polio, AIDS and the common cold are all viral illnesses.
Infection with candida fungus can lead to problems such as diaper rash, vaginal yeast infections and oral thrush.
FungiMolds, yeasts and mushrooms are types of fungi. For the most part, these single-celled organisms are slightly larger than bacteria, although some mushrooms are multicelled and plainly visible to the eye. Mushrooms can't infect you, but certain yeasts and molds can.
Fungi live in the air, water, soil and on plants. They can live in your body, usually without causing illness. Some fungi have beneficial uses. For example, penicillin — an antibiotic that kills harmful bacteria in your body — is derived from fungi. Fungi are also essential in making certain foods, such as bread, cheese and yogurt.
Other fungi aren't as beneficial and can cause illness. One example is candida — a yeast that can cause infection. Candida can cause thrush — an infection of the mouth and throat — in infants and in people taking antibiotics or who have an impaired immune system. It's also responsible for most types of infection-related diaper rash.
Cryptosporidium is a protozoan that can survive outside the body for long periods of time.
ProtozoaProtozoa are single-celled organisms that behave like tiny animals — hunting and gathering other microbes for food. Protozoa can live within your body as a parasite. Many protozoa call your intestinal tract home and are harmless. Others cause disease, such as the 1993 Cryptosporidium parvum invasion of the Milwaukee water supply, sickening more than 400,000 people. Often, these organisms spend part of their life cycle outside of humans or other hosts, living in food, soil, water or insects.
Most protozoa are microscopic, but there are some exceptions. One type of ocean-dwelling protozoa (foraminifer) can grow to more than 2 inches in diameter.
Some protozoa invade your body through the food you eat or the water you drink. Others can be transmitted through sexual contact. Still others are vector-borne, meaning they rely on another organism to transmit them from person to person. Malaria is an example of a disease caused by a vector-borne protozoan parasite. Mosquitoes are the vector transmitting the deadly parasite plasmodium, which causes the disease.
Infection by one type of roundworm, known as a hookworm, can cause problems in your small intestine or lungs. The average hookworm is about half an inch long.
HelminthsHelminths are among the larger parasites. The word "helminth" comes from the Greek for "worm." If this parasite — or its eggs — enters your body, it takes up residence in your intestinal tract, lungs, liver, skin or brain, where it lives off the nutrients in your body. The most common helminths are tapeworms and roundworms.
The largest of the roundworms can be more than 12 inches long. And the largest of the tapeworms can grow to be 25 feet or longer. Tapeworms are made up of hundreds of segments, each of which is capable of breaking off and developing into a new tapeworm.
Understanding infection vs. disease
There's a distinct difference between infection and disease. Infection, often the first step, occurs when bacteria, viruses or other microbes enter your body and begin to multiply. Disease occurs when the cells in your body are damaged — as a result of the infection — and signs and symptoms of an illness appear.
In response to infection, your immune system springs into action. An army of white blood cells, antibodies and other mechanisms goes to work to rid your body of whatever is causing the infection. For instance, in fighting off the common cold, your body might react with fever, coughing and sneezing.
Warding off germs and infection
What's the best way to stay disease-free? Prevent infections from happening in the first place. You can prevent infection through simple tactics such as regular hand washing, vaccinations and appropriate medications.
Hand washing. Often overlooked, hand washing is one of the easiest and most effective ways to protect yourself from germs and most infections. Wash your hands thoroughly before preparing or eating food, after coughing or sneezing, after changing a diaper and after using the toilet. When soap and water aren't readily available, alcohol-based hand-sanitizing gels can offer protection.
Vaccines. Vaccination is your best line of defense for certain diseases. As researchers understand more about what causes disease, the list of vaccine-preventable diseases continues to grow. Many vaccines are given in childhood, but adults still need to be routinely vaccinated to prevent some illnesses, such as tetanus and influenza.
Medicines. Some medicines can help you from becoming susceptible to germs. For example, taking an anti-parasitic medication might protect you from contracting malaria if you travel to or live in an area where your risk is high. Or when you are at high risk of exposure to certain organisms — such as those that cause bacterial meningitis — your doctor may prescribe antibiotics to lower your risk of infection. Using over-the-counter antibiotic creams can decrease the chance of infection of minor cuts and scrapes. But long-term, indiscriminate use of antibiotics isn't recommended in most cases. It won't prevent bacterial infections and instead may result in a more resistant, harder-to-treat strain of bacteria when infections do occur.
When to seek medical care
Although some infectious diseases, such as the common cold, might not require a visit to the doctor, others might.
Seek medical care if you suspect that you have an infection and you have experienced any of the following:
An animal or human bite
Difficulty breathing
A cough lasting longer than a week
A fever of 100.4 F (38.0 C) or more
Periods of rapid heartbeat
A rash, especially if it's accompanied by a fever
Swelling
Blurred vision or other difficulty seeing
Persistent vomiting
An unusual or severe headache
Your doctor can perform diagnostic tests to find out if you're infected, the seriousness of the infection, and how best to treat that infection.
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