I know I post about this all the time, but it impacts our lives in so many ways. Vaccines help protect the helpless. Children under the age of one year old are too young to be vaccinated by the MMR vaccine. Measles kills and harms children. Data to support this? A recent report out of Europe has indicated that last year eight peopele died and 29 had encephalitis related to measles infections. The population with the highest incidence of serious disease? Children under the age of one. These children cannot be vaccinated. But they became infected because other individuals, who could be vaccinated were NOT vaccinated, no herd immunity.
Herd immunity is a hard concept to understand. But let’s try to understand it from the scenario above: You have a baby who cannot be vaccinated (too young/immune system weak to survive even an attenuated measles infection). Measles is a virus that can ONLY infect humans. If you have been vaccinated, the virus CANNOT infect you and you CANNOT infect your child. If everyone who comes into contact with the child also has been vaccinated, they CANNOT be infected with measles virus and therefore CANNOT infect your child. There is no virus in the environment and no place for the virus to be.
So, you have all the individuals surrounding your child vaccinated. This effectively creates a barrier around the child where no virus can lurk. Measles can only infect humans, no humans around can be infected, no infection, no reservoir for infection.
But what happens if you accidentally come into contact with someone who doesn’t vaccinate themselves and their children? This puts a hole in the barrier to infection. This gives a place where the virus can grow and replicate. It creates a reservoir of infection.
How to prevent this reservoir? According to statistics, for herd immunity to protect our most vulnerable, anywhere from 80-95% of the population has to be vaccinated to prevent transmission to at risk individuals. The range differs between pathogens, and depends on their mode of transmission. Measles is very transmissible in that it can be spread in the air through respiratory droplets.
The EU had tried to wipe measles out by 2010 by trying to vaccinate 95% of their entire population with at least two doses of vaccine. That goal was unattainable, and they are now pushing for elimination by 2015. But recent upsurge of infection makes even a goal of 2015. Just look to the chart detailing measles infections in France from the last 5 years.
Why are we seeing so many cases of measles? Fear of vaccination? Inability to get vaccines due to lack of health care? Fear of doctors? Probably all of the above. However, today there is new data being reported that a chemical we are putting into our environment may be making our vaccines less effective, and herd immunity less attainable.
Herd immunity protects those who can’t protect themselves. Vaccines are a necessary, vital aspect of protecting those individuals.
Tags: herd immunity, Measles, Vaccine
Don’t eat road kill. Now, for the majority of you out there, this shouldn’t be breaking news. However, to a Minnesota town, this may be important to discuss.
This actually occurred back in 2010 but the article is from MSNBC.com yesterday. The report is about a Minnesota high school environmental science class that was supposed to hunt, process and cook deer for a school project. The article THEN goes on to say that a seventh deer that had been hit by a car was also included and a total of seven deer were included in the project. The deer were butchered on school grounds and then cooked, shish kabob style.
Really, the utilization and consumption of the deer that had been hit wasn’t the problem. I am going to assume the animal had JUST died. There is a lovely little website that instructs you on the “How To’s” of safely consuming road kill. One of their better points is to watch out so you don’t eat rabid animals. Hmmm.
The problem that occurred in Minnesota was in the cooking of the meat that had been butchered. If you sufficiently cook meat, the bacteria that had contaminated the meat during the butchering process will be killed. Killed bacteria cannot harm you. However, the article details the problem that occurred nicely:
the meat had been skewered and cooked only to medium rare. The skewers had dragged contaminants from the meat’s surface down to the center of the kabobs, which hadn’t been cooked to a high enough temperature to kill the bacteria.
29 students out of the 117 that took part in the cook out got ill. The article also discusses that HANDWASHING (or lack-thereof ) by male students who participated in the butchering and cooking event may not have been all that carefully observed. Again, Hmmmm.
The last thing I am going to discuss with this outbreak was the strain of E. coli that caused the problem was not linked to our usual suspect O157:H7. O157:H7 is a specific strain of E. coli that has the ability to produce a Shiga-like toxin that causes bloody diarrhea as well as Hemolytic Uremic Syndrome (in about 5% of cases). The identification of the different strains of E. coli are based on the gram-negative cell wall and flagella. The strain that caused the problem in this case was O103:H2, which also has the ability to produce the Shiga-like toxin.
But more on that tomorrow.
India is trying to contain the TDR-TB outbreak by sending all patients identified with the organism to a sanatorium to try to prevent the spread of the organism. Several patients identified with TDR-TB have already died from the infection. However, there are a few things that may make this effort moot.
The first is that they are seeing transmission of the disease from patient to family members. The mother of one of the patients has been identified as having acquired TDR-TB from contact with her son.
But the second, scarier report came a day earlier when The Daily News and Analysis posted that one of the original 12 patients had “absoconded” or simply gone missing from Government agencies. This means, that with the knowledge that organism is transmissible with close contact, the fact that this 56 year old man has gone to ground in the Indian countryside, possibly the slums of India is a real problem for containment. The crowded conditions of the Indian slums or cities are the perfect environment for transmission of the organism to an entirely new set of individuals. Now to be fair, we do not know just HOW infectious TDR-TB is in regard to normal TB infectiousness. It is thought that normally TB requires close, prolonged contact before being transmitted. But as with all bacteria evolving in response to environmental and selection pressures this could change.
And the last thing that is concerning is from the first report. The local physicians are not prescribing antibiotics correctly and driving the organism from a multi-drug resistant to totally drug resistant state. It is vital that all the Indian health care providers get immediate training on proper antibiotic regimens and dosage. But with the sheer numbers of local physicians in the Indian population this will take time. Together this does not bode well for the idea of a sanatorium isolating this problem.
I saw and discussed TDR-TB in a previous post, but wanted to point out the major take home message from the Indian Express news article describing it:
An audit of the patients’ prescriptions showed that 3 of the 1st 4 patients received unsupervised 2nd-line drugs often in incorrect dosages by private practitioners in an attempt to treat their multi-drug resistant TB (MDR-TB). By the time they were referred to us, they had moved from the MDR stage and the XDR stage to TDR-TB
Over 40% of Indians have TB. According to an NPR account of this article, India has one of the highest percentages of Multi-Drug-Resistant strains of TB (110,000 new cases in 2008). But it is the inaccurate prescription of and dosage by untrained physicians that is driving the progression into TDR-TB. Only 5 of 106 physicians knew and prescribed the correct dosage. The other problem is that it is in the slum areas where the poorest Indians live where TB is spread the most rapidly, and they have the least access to decent health care.
We have to start understanding that people without proper health care are going to impact the entire world. This is a global microbial world now. And we are losing our wonder drugs.
Which is the next serious pathogen that is going to pop-up in 2012?
Stay tuned.
Tags: Darwin, drug resistance, TDR-TB, XDR-TB
People forget that antibiotics are truly wonder drugs. In class the other day, we were discussing how important antibiotics are in keeping dread diseases at bay.One of my favorites to discuss is just how terrible the disease caused by syphilis used to be.
Before the rise of antibiotics, it was the primary cause of blindness and dementia. It was a major cause of death during the Renaissance. These are just a few of the famous who are suspected of having syphilis and suffering from sypmptoms: Gauguin, Van Gogh, Lenin, Tolstoy, Lenin, Hiltler, Schubert. Al Capone is described as having neurosyphilis dementia (tertiary syphilis) while in Alcatraz, and is reported to have died from a stroke induced by the condition.
In today’s world we talk about syphilis with knowing smiles and whispers behind hands. This is because a single shot of penicillin or azithromycin cures the infection. According to the CDC website there were 36,000 cases of syphilis in 2006. Half of those would have suffered severe consequences from the illness and probably transmitted the infection to loved ones.
Antibiotics ARE miracle drugs.
I am making predictions in this first post of the new year. I have a pretty strong suspicion that microorganisms are going to be in the headline in a much more dominant way this year.
The reasons? Let’s just start with these as three examples:
1. The plasmid called NDM-1 (New Dehli Metallo-beta-lactamase 1) can confer antibiotic resistance to almost ALL antibiotics to any bacteria that picks it up.
2. It was just announced that 12 cases of TDR-TB (Totally drug-resistant Tuberculosis) have appeared in India.
3. The scientific community is at odds over the possible publication of the sequence of the flu virus (generated experimentally) that could be transmissible between humans.
So gird your immunological loins, it may be a rough year….and welcome to 2012!
I tell my students all the time about my three big bads…motorcycles, smoking and sun damage.
Motorcycles are great…if you need an organ transplant. I have worked in a transplant lab where we harvested organs for people needing a functional heart, kidney, liver, or a number of other organs. Motorcyclists are the major supplier of these resources. This is a quote from an article by the New York Times on the subject:
“Motorcycle fatalities are not only our number one source of organs,” said one surgeon. “They are also the highest-quality source of organs, because donors are usually young, healthy people with no other traumatic injuries to the body, except to the head.
As for smoking, not only do we know that it is THE major factor that contributes to COPD, but second hand smoke increases the risks for those of the people you love who have to live with you:
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According to the WHO, passive smoking carries serious risks, especially for children and those chronically exposed. The WHO estimates that passive smoking is associated with a 10 to 43 percent increase in risk of COPD in adults.
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Although cigarette smoking is the primary cause of COPD, the WHO estimates that there are 400,000 deaths per year from exposure to biomass fuels.
Now, a new study published in the Journal of Investigative Dermatology is citing that a specific type of UV irradiation may be more dangerous than previously thought. The study showed an increased production of thymine dimers in the deeper layers of the skin, the dermis from UVA-1 irradiation that what was seen with UVB irradiation. Thymine dimers are the main cause of skin cancer. Previously it was thought that UVB rays were more dangerous, but it is the UVA rays that cause deeper damage. Where do we primarily find UVA-1 rays? UVA rays are the main irradiation found in tanning beds. California has just banned tanning beds for anyone under the age of 18 due to skin cancer concerns.From the article, State Senator Ted Lieu:
If everyone knew the true dangers of tanning beds, they’d be shocked. Skin cancer is a rising epidemic and the leading cause of cancer death for women between 25 and 29.
France and England also have banned tanning bed use for individuals under the age of 18. I am going to give the last word on this to a doctor quoted in a USA Today article on the topic:
“Indoor tanning is like smoking for your skin,” said Dr. Doris Day, a dermatologist at Lenox Hill Hospital in New York City. “It’s the single worst thing you can do in terms of skin cancer and premature aging.”
Many indoor tanning salons advertise that tanning beds can help boost the body’s production of vitamin D, known as the sunshine vitamin because skin makes it when exposed to the sun’s rays. “This is nonsense and an excuse,” Day said. “We know people burn in tanning beds and that UVA and UVB are toxic.”
Tags: cancer, tanning bed, thymine dimer, UVA, UVA-1
Yes it is called shmeat. But what is it? Technically, it is meat cells grown in a test tube. Yes, meat in a test tube.
But you ask, what ARE meat cells? Meat cells are muscle cells that have been developed from stem cells in animals. They are cultured to become muscle cells and then, tissue. Therefore, if you want nuggets, you would take stem cells from chicken and try to create breast meat. You want steak? Stem cells from cattle and so on… So far, the only shmeat that has been produced is a layer of meat cells that are only a few centimeters across.
Interestingly, they have progressed from creating this tissue by using blood/animal products, to developing a system that utilizes a cyanobacterium as the nutrient and energy source to grow the meat. Cyanobacteria hydrolysate utilizes light and carbon dioxide for growth. Essentially, we could create meat using photosynthesis.
The first real product to be made? Sausage. Smeat Sausage. One of my friends wonders if it is going to taste like shmit.
Tags: cyanobacteria, stem cells, synthetic meat
Fomites are inanimate objects that when contaminated with infectious agents can transfer disease to a new host. Normally, when we think of a fomite, we usually conjure obvious ones…a scalpel, a phone, a pencil. But sometimes it is the most obvious objects that are at fault, but still overlooked. For example, a small study published in 2009 indicated that not only were 15% of all stethoscopes tested contaminated with MRSA, but also that the MRSA on the stethoscopes had survived there for upwards of 60 days!
Also, most hospitals do not allow artifical fingernails or nail enhancement on health care workers because the false nails (fomites) consistently have higher bacterial loads than natural nails. Also, there have been a number of studies (example) where doctor’s neckties were found to be commonly contaminated with bacteria. Not all that shocking when you think about how often men wash their ties?
But most recently, a new study published in the American Journal of Infection Control, 60-65% of scrubs and lab coats of health care workers tested in the report were contaminated with potentially dangerous bacteria. The pockets, sleeves, and abdominal areas were tested. Additionally, 21 of nurse’s samples and 6 from the doctor’s samples taken were drug resistant. Eight of the samples were identified as MRSA (methicillin resistant Staph aureus ).
This is not exactly news, as there are several previous articles detailing how bacteria can survive on various cloth and plastic surfaces, as well as on lab coats in general.
Hospitals and doctors are struggling to get it right, though. Just announced in 2010, the DocFroc:
lab coats and scrubs that are embedded with Tri-Active, an FDA approved silver-based antimicrobial compound that can kill resistant micro-organisms such as MRSA, ECOLI and Salmonella.
It appears that the most important factor in prevention of disease is to simply better identify what has been transferring disease in the first place.
Tags: false nails, fomite, lab coat, nosocomial