Swine Flu Outbreak Illuminated By Avian Flu Research

A new study by University of Maryland researchers suggests that the potential for an avian influenza virus to cause a human flu pandemic is greater than previously thought.  Results also illustrate how the current swine flu outbreak likely came about. 
As of now, avian flu viruses can infect humans who have contact with birds, but these viruses tend not to transmit easily between humans.  However, in research recently published in the Proceedings of the National Academy of Sciences, Associate Professor Daniel Perez from the University of Maryland showed that after reassortment with a human influenza virus, a process that usually takes place in intermediary species like pigs, an avian flu virus requires relatively few mutations to spread rapidly between mammals by respiratory droplets.
"This is similar to the method by which the current swine influenza strain likely formed," said Perez, program director of the University of Maryland-based Prevention and Control of Avian Influenza Coordinated Agricultural Project, AICAP.  "The virus formed when avian, swine, and human-like viruses combined in a pig to make a new virus.  After mutating to be able to spread by respiratory droplets and infect humans, it is now spreading between humans by sneezing and coughing."
In his study, Perez used the avian H9N2 influenza virus, one that is on the list of candidates for human pandemic potential.  Using reverse genetics, a technique whereby individual genes from viruses are separated, selected, and put back together, Perez and his team created a hybrid human-avian virus.  Their research hybrid has internal human flu genes and surface avian flu genes from the H9N2 virus.  Though it comes from a different strain of avian flu than the one that contributed to the hybrid virus now causing the swine flu outbreak, Perez's research virus is similar in origin to the swine flu virus, in that both involved a combination of avian and human influenza viruses.
Perez infected ferrets (considered a good model for human influenza transmission) with the virus he created, and allowed the virus to mutate in the species.  Before long, healthy ferrets that shared air space but not physical space with the infected ferret had the virus, showing that the virus had mutated to spread by respiratory droplets.
When the genetic sequences of the mutant virus and original hybrid virus were compared, the only differences were five amino acid mutations, three on the surface, and two internally.  Two of the surface mutations were determined to be solely responsible for supporting respiratory droplet transmission.  Because so few mutations were necessary to make the hybrid H9N2 transmissible this way, they concluded that after an animal-human hybrid influenza virus forms in nature, a human pandemic of this virus is potentially just a few mutations away.
"We do not know if the mutations we saw in the lab are the same that have made the H1N1 swine flu transmissible by respiratory droplets," Perez said.  "We will be doing more research on the current swine flu strain to study its specific genetic mutations."
Perez found that one of the two of the genetic mutations in his lab strain that enabled respiratory transmission between mammals was on the tip of the HA surface protein, one of the sites where human antibodies created in response to current vaccines would bind.
"Because the binding site of the mutant virus is different from the virus upon which the vaccine is modeled, it may mean that current vaccine stocks would not be as effective against the H9N2 mutant strain as previously anticipated," said Perez.  "We should keep this in mind when designing vaccines for an avian flu pandemic in humans."
However, scientists cannot predict what the actual mutations will look like if and when they occur in nature, or even which strain of avian influenza will mutate to infect mammals.
"This is just the tip of the iceberg," said Perez.  "Many more studies have to be done to see which combinations of mutations cause this type of transmission before we can design the appropriate vaccines."
Perez will be talking this week with the NIH and the CDC to discuss his team's role in researching the current swine flu virus strain.  Perez will likely do studies related to vaccine development, virus transmission between humans and animals, and the pathogenesis of the virus.
A virus vaccine is derived from the virus itself. The vaccine consists of virus components or killed viruses that mimic the presence of the virus without causing disease.  These prime the body's immune system to recognize and fight against the virus. The immune system produces antibodies against the vaccine that remain in the system until they are needed. If that virus, or in some cases a closely similar one is later introduced into the system, those antibodies attach to viral particles and remove them before they have time to replicate, preventing or lessening symptoms of the virus.
The immune system also retains antibodies to a virus after being infected with it, so humans have general immunity to human strains of avian influenza strains.  But humans do not generally have immunity to avian flu strains because they have not been infected by them before.  The surface proteins are sufficiently different to escape the human immune response.  Avian flu strains are therefore more dangerous for humans because the human immune system cannot recognize the virus or protect against it.

Novel H3N1 Swine Influenza Virus Identified In Pigs In Korea

For the first time, researchers from the U.S. and abroad have identified the H3N1 swine influenza virus in domestic pigs in Korea. They report their findings in the November 2006 issue of the Journal of Clinical Microbiology.
A highly infectious respiratory pathogen, the H3N1 influenza A virus is a new genetic reassortment of influenza viruses first identified in pigs in the U.S. in 2004. The virus can be found in birds and mammals (including humans and pigs), but is not generally transmissible between birds and humans. Pigs are believed to be susceptible to both origins resulting in them being deemed "mixing vessels" for the virus and ultimately reinforcing concerns of zoonosis and pandemic outbreaks.
In March and April of 2006 researchers isolated H3N1 influenza A viruses in pigs with respiratory diseases at two commercial swine farms in Korea. Further testing confirmed the H3N1 viruses presenting were reassortments of an H3 human-like virus and other genes from swine influenza viruses and that pig-to-pig and farm-to-farm transmission had occurred. Additionally, analysis of experimentally infected mice suggested the potential to transmit the virus between pigs and other mammalian hosts.
"We report here the first isolation and characterization of H3N1 swine influenza viruses from pigs with respiratory disease in Korea," say the researchers. "Given the evidence that pigs can support the reassortment of influenza viruses from humans and other species, it is prudent that we enhance surveillance for atypical influenza viruses in pigs as part of overall pandemic preparedness efforts."
(J.Y. Shin, M.S. Song, E.H. Lee, Y.M. Lee, S.Y. Kim, H.K. Kim, J.K. Choi, C.J. Kim, R.J. Webby, Y.K. Choi. 2006. Isolation and characterization of novel H3N1 swine influenza viruses from pigs with respiratory diseases in Korea. Journal of Clinical Microbiology, 44. 11: 3923-3927.)

Taking Sharper Aim At Stomach Ulcer Bacteria

Scientists are reporting discovery of a much sought after crack in the armor of a common microbe that infects the stomachs of one-sixth of the world's population, causing stomach ulcers and other diseases. They identified a group of substances that block a key chemical pathway that the bacteria need for survival
Their study, which could lead to new, more effective antibiotics to fight these hard-to-treat microbes, is scheduled for the October 16 issue of ACS Chemical Biology, a monthly journal.
Javier Sancho and colleagues note in the new study that Helicobacter pylori (H. pylori) bacteria infect the stomach lining and can cause gastritis and ulcers. Treatment with broad-spectrum antibiotics can cure H. pylori infections. However, an estimated one billion people remain infected worldwide because of the cost of existing antibiotics and the emergence of antibiotic resistant strains of the bacteria, the researchers say.
The scientists knew from past research that blocking flavodoxin, a key protein that H. pylori needs for survival, could be the key to developing narrow-spectrum antibiotics that specifically target H. pylori. Sancho's team screened 10,000 chemicals for their ability to block flavodoxin and identified four that showed promise. They then showed that three of the four substances killed H. pylori in cell cultures and did not have any apparent toxic effects in lab animals. "These new inhibitors constitute promising candidates to develop new specific antibiotics against H. pylori," the study states.

Targeting Specific Disease-Causing Bacteria In The Mouth

Research to develop a narrow-spectrum antibiotic that can target a particular species of bacteria without harming the other "good" bacteria present was described at the Society for General Microbiology meeting at Harrogate April 2.
Professor Kim Brogden from the University of Iowa attached a broad-spectrum antibiotic to a protein that targets a receptor on a particular bacterium's surface. When this newly-formed narrow-spectrum antibiotic was tested on a mix of bacteria that included the target organism, Porphyromonas gingivalis, a cause of gum disease, low concentrations of the antibiotic killed the P. gingivalis bacteria but left the other two bacterial species in the mix untouched.
Antibiotics have clear clinical benefits in treating oral infections like gum (periodontal) disease. This therapy reduces the number of harmful bacteria in patients who have received non-surgical and surgical treatments. Hard and soft tissue damage is much less in patients who have received antibiotics than in patients who have not received these drugs. Unfortunately, complications are associated with antibiotic use.
Side effects such as nausea, vomiting, abdominal discomfort, diarrhoea, allergic skin rashes and fever can be caused by penicillin and related drugs. Overuse of antibiotics leads to the development of drug-resistant bacteria. And antibiotics can kill the normal bacterial population of the mouth, urogenital tract, and gastrointestinal tract. This can lead to infections by opportunistic Candida albicans yeast in the mouth and urogenital tract or the bacterium Clostridium difficile in the gastrointestinal tract.
A targeted approach is needed to kill specific disease-causing bacteria in complex environments, said Professor Brogden. "We are developing an antibiotic that can target and kill a particular pathogen without harming or altering the composition of the normal, more beneficial bacteria in the body. Such a product would provide a variety of new treatments for oral diseases as well as a means of prevention."

New Bacterial Species Found In Human Mouth

Scientists have discovered a new species of bacteria in the mouth. The finding could help scientists to understand tooth decay and gum disease and may lead to better treatments, according to research published in the August issue of the International Journal of Systematic and Evolutionary Microbiology.
"The healthy human mouth is home to a tremendous variety of microbes including viruses, fungi, protozoa and bacteria," said Professor William Wade from King's College London Dental Institute. "The bacteria are the most numerous: there are 100 million in every millilitre of saliva and more than 600 different species in the mouth. Around half of these have yet to be named and we are trying to describe and name the new species."
Scientists studied healthy tissue as well as tumours in the mouth and found three strains of bacteria called Prevotella that could not be identified. Prevotella species are part of the normal microbial flora in humans and are also associated with various oral diseases and infections in other parts of the body. The researchers named the new species Prevotella histicola; histicola means 'inhabitant of tissue'.
"Interestingly, this species was isolated from within the oral tissues, both in oral cancers and normal, healthy tissue," said Professor Wade. "This confirms other work showing that oral bacteria can invade both tissues and individual cells."
Tooth decay and gum disease are the most common bacterial diseases of man and are caused by changes in the microbes normally present in the mouth. To understand these diseases better, scientists first need to know which bacteria are present in human mouths. Understanding the composition of the oral microbiota will also help scientists devise new prevention measures and treatments for oral diseases.
"A detailed description and name for each species of bacteria are needed so that different laboratories can recognise all of the bacterial species present in the mouth," said Professor Wade.

Report Focuses On The Role Good Microbes Play In Future Medicine

Not all bacteria are bad. In fact, beneficial microbes could represent the future of medicine, with the potential to treat a variety of diseases in humans and animals from diarrhea and eczema to gum disease and autoimmune disorders, according to a report released by the American Academy of Microbiology, Probiotic Microbes: The Scientific Basis.
"Theoretically, beneficial microorganisms could be used to treat a range of clinical conditions that have been linked to pathogens, including gastrointestinal problems like irritable bowel syndrome and inflammatory bowel disease, oral diseases like tooth decay and periodontal disease, and various other infections, including vaginal infections and possibly skin infections. Probiotics could also conceivably be put to use in preventing disease or thwarting autoimmune disorders. A number of these possibilities are being explored in research labs and hospitals around the world," says Richard Walker of the Food and Drug Administration, a co-chair of the steering committee that produced the report.
Probiotics can help prevent and treat disease through a number of mechanisms. One way is by interacting directly with the disease-causing microbes, making it harder for them to cause disease. An example of this is the ingestion of probiotic bacteria to prevent or treat diarrhea. The organisms help reinforce the natural bacterial barrier that exists on the lining of the digestive tract providing additional protection against pathogenic organisms that can cause diarrhea.
"Several probiotics have been shown to shorten the duration of acute watery diarrhea caused by rotavirus in children. Other causes of diarrhea may also be addressed through probiotics," says Carol Wells of the University of Minnesota, a member of the steering committee.
Another example of microbe-microbe interaction in probiotics is a phenomenon known as "competitive exclusion" in which beneficial microbes directly compete with disease-causing microbes for food and other resources, eventually crowding them out. One potential application of competitive exclusion would be colonizing the mouth with beneficial bacteria to prevent the growth of bacteria that cause cavities and gum disease.
Probiotics also help prevent disease by interacting with and strengthening the immune system.
"Exposure to commensal organisms is necessary for the appropriate development of both the innate and acquired immune systems. Once established, probiotic organisms interact with these immune defenses, possibly changing the nature of the immune response to other antigens, including commensal and pathogenic organisms," says Walker.
The report is the outcome of a colloquium convened by the American Academy of Microbiology in November 2005 to discuss the current state of knowledge regarding probiotics. Participants with expertise in microbiology, medicine, periodontics, animal science, immunology, nutrition and other fields met to discuss a variety of issues associated with the field of probiotics. In addition to providing an overview of the current state of and potential for probiotic research, the report also offers specific recommendations to help advance the field.
In addition to those listed above, some other potential future applications of probiotics identified in the report include treating antibiotic-resistant infections, encouraging weight gain in newborns and children with AIDS, reducing the incidence of kidney stones, and reducing the recurrence of bladder tumors.

Probiotic Bacteria Don't Make Eczema Better, And May Have Side Effects, Study Shows

There is no evidence probiotics can relieve the symptoms of eczema, but there is some evidence that they may occasionally cause infections and gut problems. These findings from The Cochrane Library come at a time when use of probiotics to treat eczema is increasing.
Eczema is an itchy skin condition that affects more than 1 in 20 people at some time in their lives and is especially common in children. Its cause is complex and not well understood, but sufferers do have different bacteria in their guts compared to unaffected people. Consequently, some nutritionists have suggested that eating live gut-dwelling bacteria, such as those found in probiotic yoghurts and some infant formulas, could be beneficial.
"Some doctors are recommending probiotics as a cheap treatment for eczema, but having carried out a systematic review we have found no evidence that they work for treating eczema," says lead researcher Robert Boyle of Imperial College, London, UK.
The Cochrane Researchers looked at 12 studies that together involved 781 children diagnosed with eczema. These studies compared severity of the disease in children given live bacteria to severity in those given a placebo. The researchers found that probiotics provided no significant health improvement. Similar bacteria were given across all studies, so the researchers could not rule out the possibility that other strains might be beneficial. Moreover they found that in separate studies 46 patients had been reported to suffer side effects from using probiotics, including infection and bowel damage.
"There is no evidence that probiotics are a worthwhile treatment for eczema, and they may be harmful for certain groups of people," says Boyle. "However, further studies of new probiotics are needed, because it is possible that different types of probiotics which haven't yet been studied in eczema treatment could be more effective."

Sushi Scares - Infectious Diseases Associated with Eating Sushi or Raw Fish

In Japan, it’s part of the national diet. In the U.S., it has grown in popularity since the late 1970s. Sushi, often mistaken for its counterpart “sashimi”, which is sliced raw fish, is actually a sweetened vinegared rice usually combined with other ingredients, including raw fish. While this delicacy is now enjoyed worldwide, there is also growing concern about the risk of infections from consuming raw fish.
Risks of eating raw fish
Anisakis and other parasites
Human infection by Anisakis simplex (herring worm) and other nematodes, or roundworms, is caused by eating certain raw or undercooked fish. Ingestion of the worm can result in severe abdominal pain, nausea, and vomiting within hours of ingestion and has been misdiagnosed as appendicitis or other stomach diseases. If the worms don’t get coughed up or vomited out, they can burrow into the walls of your intestines and cause a localized immune response. The worms eventually die and are removed by the immune system. In severe cases, physical removal of the worms by endoscopy or surgery is needed to reduce the pain. They can in rare, severe cases cause anaphylactic shock as well. Albendazole may be used to treat mild cases.
Vibrio species
The bacterial species, Vibrio parahaemolyticus has been associated with consumption of raw or undercooked fish and shellfish, particularly oysters. Infection by these bacteria can cause symptoms including diarrhea, abdominal cramps, nausea, vomiting, headache, fever, and chills. The infection is usually self limiting and typically does not require antibiotics.
Another Vibrio species, Vibrio vulnificus, has been found in oysters, clams, and crab. In healthy people, ingestion of this microbe can cause vomiting, diarrhea, and abdominal pain, but in people with liver disease or weakened immune systems, the microbe can enter the bloodstream, causing the life-threatening condition of septicemia.
Gastroenteritis from Vibrio vulnificus is rare, but it can happen on occasion. Rather, these microbes are more commonly associated with wound infections through open sores exposed to water harboring the bacteria. Examples include scrapes when opening oysters or working on boats. These types of wound infections are most severe in people with weakened immune systems.
Should I avoid sushi?
The risk of eating raw or undercooked fish in the U.S. is very small, with fewer than 10 cases of Anisakis infection diagnosed each year (although many cases are likely unreported). In addition, the FDA has provided several guidelines for retailers who sell fish intended to be eaten raw. These guidelines include freezing the fish to -31°F for 15 hours or -4°F for 7 days to kill parasites and physical examination known as “candling” for the presence of worms.
Who should avoid raw fish?
People with liver disorders or weakened immune systems (i.e. small children, the elderly, and pregnant women) have a greater risk for more severe outcomes from infection and should practice discretion when eating at a sushi bar.



ARTICLE COPIED FROM THE GIVEN LINK

http://infectiousdiseases.about.com/od/g/a/Sushi.htm

INFECTION FROM MICROBES IN CONTAMINATED FOODS

It has been estimated that more than 76 million cases of foodborne disease occur every year in the US. Of these, 325,000 cases result in hospitalization, and 5,000 cases result in death. Children and older adults are usually the hardest hit, since they tend to have underdeveloped or weakened immune systems.

What Is a Foodborne Disease?

The Centers for Disease Control defines a foodborne illness as a disease caused by consuming foods or drinks contaminated with microbes or other harmful substances. Most foodborne diseases are caused by a variety of bacteria, viruses, or parasites.

How Do Contaminating Microbes Make You Sick?

There are 2 major mechanisms used by foodborne pathogens that cause disease:

1. Toxins. Bacteria can produce toxins or poisons that cause vomiting and/or diarrhea. Depending on the strain of bacteria, these toxins can be already present in the food you consume or produced in your body after you ingest the microbe.
2. Tissue Invasion. Some microbes can penetrate the lining of your intestines, causing an immune response that results in gastrointestinal symptoms.

Does Reheating the Food Kill the Germs?

Most microbes are killed by temperatures greater than 160 F (78 C), except for Clostridium, a type of bacteria that can form heat-resistant spores. However, there are common food-contaminating bacteria, such as Staphylococcus aureus, that produce toxins that are not affected by heating.

Prevention Tips

The Partnership for Food Safety Education recommends following the guidelines for prevention of foodborne illnesses:

1. Wash hands and surfaces often.
   • Use hot, soapy water to wash cutting boards, dishes, utensils, and counter tops.
   • Consider using disposable towels to clean kitchen surfaces, since bacteria can build up in damp, dirty cloth towels.
   • Wash all fresh fruits and vegetables under running tap water. This includes those with skins or rinds that are not eaten.
2. Separate: Don’t cross-contaminate
   • Keep raw meats and their juices separate from ready-to-eat foods.
   • Use separate cutting boards for fresh produce and raw meats.
   • Don’t reuse old dishes that held raw meats or eggs.
3. Cook: Cook foods to proper temperatures
   • Use a food thermometer to make sure your roasts, steaks, and fish are cooked to at least 145°F, poultry (inner part of thigh and wing and thickest part of breast) to 165°F, and ground meat to 160°F.
   • Don’t use recipes with raw or only partially cooked eggs.
   • Reheat sauces, soups, and gravy to boiling, and other leftovers to 165°F.
   • When microwave cooking, stir and rotate food for even cooking.
4. Chill: Refrigerate promptly
   • Make sure your refrigerator is 40°F or below, and your freezer is 0°F or below.
   • Meats, eggs, and other perishables should be refrigerated or frozen as promptly as possible.
   • Defrost food in the refrigerator, under cold water, or in the microwave. Never defrost at room temperature.
   • Food should be marinated in the refrigerator.
   • Perishable foods should be refrigerated within 2 hours of sitting at room temperature.
   
   
   
    http://infectiousdiseases.about.com/od/g/a/Foodborne.htm
   

BACTERIA AND FOOD POISONING

There are over two hundred types of bacteria, viruses and parasites that can cause foodborne diseases. Reactions to these germs can range from mild gastric discomfort to death. The easiest way to prevent foodborne illness is to properly handle and cook foods. This includes washing your hands and utensils carefully and cooking meat thoroughly.

Below is a list of a few bacteria that cause foodborne diseases, along with the foods that are associated with them, as well as symptoms that are likely to develop from ingesting the contaminated foods.


Bacteria and Food Poisoning

• Microbe - Aeromonas hydrophila
• Affiliated Foods - Fish, Shellfish, Beef, Pork, Lamb, and Poultry
• Diseases - Gastroenteritis, Septicemia
• Symptoms - Diarrhea, Blood and Mucus in Stool

• Microbe - Bacillus cereu
• Affiliated Foods - Meats, Milk, Rice, Potato, and Cheese Products
• Diseases - B. cereus Food Poisoning
• Symptoms - Diarrhea, Abdominal Cramps, Nausea

• Microbe - Campylobacter jejuni
• Affiliated Foods - Raw Chicken, Unpasteurized Milk, Non-chlorinated Water
• Diseases - B. cereus Campylobacteriosis
• Symptoms - Diarrhea, Abdominal Cramps, Nausea and Fever, Headache and Muscle Pain

• Microbe - Clostridium botulinum
• Affiliated Foods - Canned Foods Including: Vegetables, Meats, and Soups
• Diseases - Foodborne Botulism
• Symptoms - Weakness, Double Vision and Vertigo, Difficulty in Speaking, Swallowing, and Breathing, Constipation

• Microbe - Clostridium perfringens
• Affiliated Foods - Non-refrigerated Prepared Foods: Meats and Meat Products, Gravy
• Diseases - Perfringens Food Poisoning
• Symptoms - Severe Abdominal Cramps, Diarrhea

• Microbe - Escherichia coli O157:H7
• Affiliated Foods - Undercooked Meats, Raw Ground Beef
• Diseases - Hemorrhagic colitis
• Symptoms - Severe Abdominal Pain, Watery and Bloody Diarrhea, Vomiting

• Microbe - Listeria monocytogenes
• Affiliated Foods - Dairy Products, Raw Vegetables, Raw Meats, Smoked Fish
• Diseases - Listeriosis
• Symptoms - Flu-like Symptoms, Persistent Fever, Nausea and Vomiting, Diarrhea

• Microbe - Salmonella spp.
• Affiliated Foods - Poultry and Eggs, Milk and Dairy Products, Raw Meats, Fish, Shrimp, Peanut Butter
• Diseases - Salmonellosis
• Symptoms - Nausea, Vomiting, Abdominal Pain, Fever, Headache, Diarrhea

• Microbe - Shigella spp
• Affiliated Foods - Poultry, Milk and Dairy Products, Raw Vegetables, Fecally contaminated water, Salads: Potato, Chicken, Tuna, Shrimp
• Diseases - Shigellosis
  
• Symptoms - Diarrhea, Abdominal Pain, Fever, Vomiting, Blood or Mucus in Stool

• Microbe - Staphylococcus aureus
• Affiliated Foods - Poultry and Egg Products, Meat Products, Dairy Products
• Diseases - Staphyloenterotoxicosis, Staphyloenterotoxemia
• Symptoms - Abdominal Cramping, Nausea and Vomiting, Prostration

• Microbe - Vibrio cholerae
• Affiliated Foods - Contaminated Water, Shellfish
• Diseases - Cholera
• Symptoms - Watery Diarrhea, Abdominal Pain, Dehydration, Vomiting, Shock

ARTICLE COPIED FROM THE GIVEN LINK ANY COMMENTS REGARDING THIS INFO MUST BE SUBIMTTED TO THE GIVEN LINK

http://biology.about.com/od/bacteriology/a/aa072706a.htm