Sunday, February 10, 2019

Alligators, Parking Lots and International Health Initiatives

We stayed at a hotel in Florida a little while ago. It was next to a forested lot with a canal surrounded by a high chain link fence. One day as we left the hotel, my boys asked if there were alligators in the forest next door. We responded that we hadn’t seen any, but it was possible. My husband (who is a wonderful father and very protective) said that because of the potential threat of alligators, he didn’t want our two year old daughter running around unattended. I reminded him that before she could get over to the fenced in, forested lot with a canal and possible alligators, she would have to get through the parking lot, where she was far more likely to be hit by a car. So yes, we needed to watch her, but cars were a more pressing danger than alligators.

This isn’t to say that I’m not concerned about alligators or don’t think we need to take precautions against them, it’s just that I’m concerned about cars in this scenario. Are there other situations where I would be more concerned about alligators than cars? Yes. If we were camping in a place where alligators live and there was a pond nearby and especially if it were alligator mating season, you bet I would be concerned about alligators, probably even more so than parking lots.

A Hierarchy of Causes of Death


I would like to propose that causes of death in developing nations are the same way. There is a hierarchy of causes of death. (Granted, this is an oversimplified hierarchy, but there's a framework here.) At the bottom, you have death from widespread, ongoing conflict in a region or nation. This is when you have atrocities going on, lack of rule of law in a nation, warfare, starvation used as a weapon by dictators, etc. People are basically wondering if they are going to live through another day. That's Level 1.

In this state of mind, you think only about what is going to get you through another day. Disease, infant and maternal mortality and malnutrition are not going to be as high of priorities because the most immediate cause of death is someone trying to kill you as part of a genocide or political purge. Whether your child has enough calcium in his diet, who will deliver your baby and even HIV and polio aren’t going to matter if you can’t escape a genocide or purge.

Once the problem of conflict is solved and you’re not worrying about your village being brutally razed to the ground, you start worry about whether you will have enough food, water, and shelter. In this state of mind, you are starting to think in terms of living years rather than days. Things like malnutrition become a concern and having a permanent dwelling. That's Level 2.

But you’re still not going to be as concerned about things like infectious diseases because if you can’t get enough to eat or a house that shelters you from the elements, it won’t matter if you’ve been immunized for a disease or can get an emergency c-section. If you can’t get enough to eat or enough nutrients these things will be non-issues because rickets, pellagra, encephalopathy or severe dehydration will kill or injure you anyway. If you’re pregnant, you may die from pregnancy complications before you can even reach delivery.

Now let’s say that a majority (>75%) of your country can solve this problem. At this point you’re ready to start worrying about things like infectious diseases. Now we’re thinking in terms of living decades instead of years. This is where we might start adding in some programs to expand education. We’re no longer worried about our village getting brutally destroyed and we have enough to eat and have shelter. When those things are taken care of, diseases are what will most likely kill us. That's Level 3.

Now, let’s say that we’ve got most infectious diseases under control. Now we’re going to worry about chronic diseases like cancer, heart disease and diabetes. That's Level 4 at the top of the pyramid.

Side note: At this point in our narrative, disease control is going to take on a new level complication though with antibiotic resistance, newly emerging diseases and newly emerging strains will start to hit the scene. Then vaccine escape mechanisms, waning immunity and gaps in coverage. This can loop us back around because HIV and antibiotic resistance are big problems in developing nations as well. So this is kind of an issue that feeds back into level three with developing nations (as I said, oversimplified, but a framework nonetheless). But putting that aside for a minute, when you have good healthcare facilities and low morbidity and mortality from diseases, then you see people starting die to from chronic diseases. Suicide may also come up as a big problem here too.

People are dying. What does a hierarchy of causes of death do? Shouldn't we just help in any way?


Well, in an increasingly connected world, we have started setting worldwide goals for health. But not everybody in the world is at the same stage. Take Sudan for example. Sudan met the criteria for polio elimination in 2004…until wild poliovirus was found circulating through certain regions. Genetic sequencing of the virus revealed that it had been circulating for three years, even while Sudan was declared to have an adequate disease surveillance system. What’s wrong with this picture?

Sudan was in the middle of one of the most brutal conflicts in the world at this time (and continues). People feared for their lives on a daily basis and many fled to refugee camps. When this level of violence is present on a widespread basis, people don’t stop to think about whether their child’s summer cold might be polio and any doctors who are left in the area are dealing with massive casualties and unlikely to think about reporting polio. In my opinion, it’s naive to think that you’re going to get accurate reports about highly contagious infectious diseases when this level violence exists in a country on a daily basis.

Believe it or not, the risks of polio are actually less than the risks associated with the war in Sudan and its aftermath. According to the World Health Organization, polio leads to paralysis in 1 in 200 cases. (.5%). Of those paralytic cases, 5 to 10%. Sudan has been declared polio free since 2009 with the last cases being detected in 2008 (40) and 2009 (24). But the war in Sudan left 50,000 to 383,000 dead and 2.5 million children live with malnourishment, 700,000 in its most severe form. If we were to compare landmines and polio in their destructive capacity (not prevalence), some studies have found that landmines kill 31% of their victims and maim virtually any survivors. On a global scale, landmines exact a smaller death toll, but they are hundreds of times more deadly and more prone to maiming people than polio or a non-polio enterovirus. 

So we come to a really hard issue: If we eradicate polio in a very conflict ridden place with persistent malnutrition/starvation or a high rate of waterborne illnesses have we really got something to celebrate? Because if war, starvation and waterborne illnesses persist in these areas, the death toll remains very high, even if we eliminate a single virus. I’m not offering any solutions or course of action here, because we need to eliminate diseases as well. (Remember, I want to keep my children safe from both cars and alligators.) But in our efforts to create global goals, do we sometimes address alligators when there is a parking lot that is closer?




Thursday, December 27, 2018

What Is 40 Times Deadlier Than Measles and Why Aren’t We Talking About It?


If there was a disease out there that was 40 times deadlier than measles, you would want to know about it wouldn’t you? You would expect that there would be tons of news stories about something that devastating, wouldn’t you? You would expect your doctor to tell you about it. You would expect to see pamphlets in the hospitals. Maybe an awareness campaign. You would want to know how to prevent it, wouldn't you?

Then why are the crickets chirping about clostridium difficile and MRSA (methicillin resistant staphylococcus aureus)?

In 1951 there were 530,118 reported measles cases with 683 deaths— the highest death rate seen between 1950 and the introduction of the measles vaccine in 1963 (Centers for Disease Control, 2015). On the other hand, there are about 90,000 cases of MRSA every year in the United States, which results in about 20,000 deaths (MRSA Research Center, University of Chicago 2018). In 2011, there were approximately 500,000 cases of C. difficile and 29,000 deaths (Centers for Disease Control, 2017). 

Arriving at those numbers...


Between 1950 and 1963 there were approximately 500 deaths from measles each year (some years it was closer to 600 and others it was closer to 300, but 500 is a good number for the purposes of estimation. Reported cases of measles varied from year to year as well, but were often around 500,000). With c. diff and MRSA, we’ll use estimation again and for the purposes of this post just place the mortality for both at 20,000, even though it's been a little higher for c. diff. (We'll use conservative estimates for the sake of argument.) So roughly 40 times more people die from each c. diff and MRSA every year than did from measles in the years before the first measles vaccine. 

Just let sit for a minute. 

Why haven't you heard about this?


Alright, so we’ve established that c. diff and MRSA are BIG problems. So why aren’t these lethal diseases getting the same exposure as other diseases that have a fraction of the destructive capacity? A couple of theories I have:



Monday, October 8, 2018

The Problem With Doc McStuffins

One day I had a text exchange with my sister who is a nurse. My boys had watched another episode of Doc McStuffins while I was working on my public health homework. Once again I found myself researching the long list of problems with American health care. (In comparison to other developed nations, mind you.) I texted, "What would it look like if Doc McStuffins actually reflected what real health care looks like? They wouldn't put that on Disney!" Let's face it, Doc McStuffins' Toy Hospital bears almost no resemblance to a real American hospital:

  • There is no bureaucracy
  • None of the departments are ever underfunded or understaffed
  • None of the sick/injured toys or their families are abusive to Doc or her staff
  • Doc and her staff are always nice to each other
  • Doc and her staff don't abuse opioids
  • Doc and her staff never have to be reminded to wash their hands
  • None of the sick and injured toys pick up a nosocomial infection or antibiotic resistant infection at the Toy Hospital
  • None of the sick/injured toys have to worry about whether their health insurance will pay for treatment or if they will have to declare bankruptcy to deal with astronomical medical bills-- especially when insurance companies don't pay out
  • The treatments always work; there are no wrong doses, wrong medications, or other errors
  • Doc and her staff are always operating on a full night's sleep
  • Doc and her staff never have to deal with mass casualty incidents, sudden upswings of infectious diseases or toys who have no business being in the ER but are there anyway 
Doc McStuffins represents our aspirations for health care. We want our hospitals and health care system to be like Doc McStuffins Toy Hospital. But we have to realize that when we deal with health care, we are very far away from that ideal. Keeping that in mind will help us make the changes we need to rather than becoming embittered or in denial.

Sunday, May 20, 2018

Health Care Cows


Remember the “Government Cows” bit that started circulating in the 90’s? (And has expanded since then.) What a great way to concisely teach about different forms of government. We need the same for health care. So allow me to introduce…

Health Care Cows!!!


United States- The government owns some cows for the disabled, elderly and low-income. A few charities own cows too. But most of the cows are owned by big, for-profit corporations. Corporate dairy farms compete with each other for customers by acquiring the latest technology in milking machines and barns. All these gadgets are expensive to buy and maintain, so the dairy farms mark up their dairy products to cover the costs. Before the Affordable Milk Act, milk delivery services did not have to actually deliver milk if they didn’t feel like it. With so many milk delivery services, administrative costs are sky high, which requires more price mark-ups. Since there are no price caps on cheese, cheese manufacturers mark up their prices as much as they want to. Cheese manufactures can also receive donations to keep developing new experimental cheeses for many high-profile diseases. You go into debt and use crowdsource funding to pay for your milk and cheese. Your neighbor gets a goat and starts producing milk from the backyard for her family.

Veterans Administration- You show up to the Veterans’ Dairy at your scheduled time to pick up your milk. The dairy tells you they canceled your milk pick-up appointment and you have to reschedule it. Again.

Canada- The territorial and provincial government owns most of the cows and the federal government owns some too. Dairies get new milking machines based on what is needed in a given area. You pay higher taxes than Americans, but your milk is free and cheese is very low cost. 

Germany- The government owns most of the cows. Starting in 1883, everyone pays into a collective dairy fund and everyone who pays into it must receive dairy products as needed and at a very low price.

United Kingdom- The government owns most of the cows and regulates the dairy products, but people who want to are free to use cows and dairies from for-profit corporations or private businesses. (Most don't.) You pay higher taxes than Americans, but your milk is free and cheese is very low cost. There are price caps on milking machinery and cheese. Every year, the government and the cheese manufacturers meet and set an upper limit on the price for cheese. If the cheese manufacturers make more of a profit than the government has set, they must give the excess profits back to the government. The grocery stores get incentives from the government for selling generic cheese.

Japan- Cows and dairy farms are owned by for-profit corporations or as private businesses, but dairy delivery services have limits on how they much they can charge and they have to deliver milk to all the people on their route. Every couple of years, the government and the the dairy farmers and cheese manufacturers meet and set an upper limit on the price of milking technology and cheese. 

Cuba- The government owns all the cows and spends 10% of its GDP to give you free healthcare. You are not allowed to criticize the government, but you are healthier than people in Florida.


Singapore- The government owns some cows and private corporations own some cows- but the government regulates all the cows. The government regulates the number of dairy farmers and has some control over their wages and uses bulk purchasing power to buy cheese at very low prices. Singapore’s cows are so low-cost and give such great milk that Americans take vacations to get milk in Singapore and still save money over buying milk in their own country. 

Russia- The government owns the cows and gives you free milk— on paper. In reality, you are required by the government to also pay for a private milk delivery service as well as taxes for your government milk and often you need to bribe the grocer to actually give you safely drinkable milk. Dairies in the city are often relatively clean… dairies in more rural areas are not.

Iraq- In 1980, you had some of the best cows and dairy farms in the Middle East. Then a ruthless dictator cut funding to health care by 90 percent and there were almost no cows. Since 2004, the international community is working to get cows, dairies, farmers and grocery stores back. Right now, the record keeping on how many cows, dairy farms and grocery stores are needed in the country and its provinces is patchy and the World Dairy Organization is working with the Ministry of Dairy to get cows and dairies to meet the needs of the population.

Afghanistan- Access to cows and dairy has been sketchy for a while. After the Soviet Union pulled out of Afghanistan in 1989, warring factions within the country destroyed most of the cows. Then the Taliban took over and prevented cows from coming back. If you were lucky, you were able to find a goat to give you milk from time-to-time. Since the Taliban was deposed,   non-governmental organizations have played a big role in bringing cows, dairy farms and grocery stores back. Small dairy farms with a  few cows are popping up throughout the country. One exciting new initiative involves training women as dairy farmers.

France- The government owns the cows and you pay higher taxes than Americans. You get free milk— with home delivery at any hour of the day or night.


Thursday, May 10, 2018

What is 23,000 Times More Deadly Than the Zika Virus?


It causes 23,000 deaths every year in the United States- that's more than AIDS (6,955),  childhood cancer (1,960), food borne illness (3,000), childbirth complications (650), ebola (2), and Zika (1). Heck, it causes 50 times more deaths than measles in the pre-vaccine era (450). It can cause death quickly even in young, healthy people. It's circulating everywhere. Pharmaceutical companies are doing little to develop new drugs to fight it. There is very little in the way of disease surveillance on a national and international level to track and monitor the spread of this emerging threat. If things continue as they are now, there may be 10 million deaths from this every year starting in 2050.

What is this strange threat?

You may be surprised to find out that it's antibiotic resistant infections.

Medical and public health personnel have been concerned for several years about a "perfect storm" of antibiotic resistance that is brewing: more bacteria are becoming resistant to more antibiotics and fewer new antibiotics are being developed than ever before. You may not have heard nearly as much about antibiotic resistant infections in the news as Ebola and Zika, but the threat is far more real.
The irony is that the more we use antibiotics the less effective they become because of the highly adaptable nature of bacteria. Many scientists have compared antibiotic effectiveness to resources like oil or timber or fresh water- something that is limited and must be carefully conserved.
However, all hope is not lost. There are still a few things we can each do to help fight antibiotic resistance.
  • Don't take antibiotics for colds and the flu. I heard an ER nurse in one of my classes complain about this- people show up at the emergency room with the flu and demand an antibiotic. Doctors say it happens frequently in their offices too, and they don't want to lose patients or have a confrontation, so they write a prescription just to be done with the whole situation. According to a 2012 study by the Pew Trust, 12% of Americans believe that antibiotics are very effective at treating viral illnesses like colds and flu and 36% believed that antibiotics are somewhat effective at treating viral illnesses. Dead wrong on both counts. Antibiotics are only for treating bacterial infections- and even those are becoming hit and miss as more bacteria strains become resistant to the antibiotics in current use. When you take an antibiotic unnecessarily, it gives the bacteria a chance to adapt to the antibiotic. The adapted bacteria then multiply rapidly and spread through healthcare facilities and in the community. If someone develops an infection from the resistant bacteria, they can become very sick and even die, especially if they are immunocompromised.
  • Sharing is caring...except with antibiotics. Don't share any leftover antibiotics. Giving a little leftover antibiotics to a friend or family member who is feeling sick gives any bacteria that person is carrying the chance to be exposed to and adapt resistance to the shared antibiotic.
  • Finish the complete course of antibiotics- even if you are feeling better. Taking the full course of antibiotics increases the chances of killing the bacteria so they don't survive and develop resistance to the antibiotic you are taking.
  • Try some essential oils as a first line of defense. 
    If you're into essential oils and use them to try to boost your immune system during the fall and winter, you may actually be on the right track. A 2004 study by Edwards-Jones, Buck, Shawcross, et. al. found that a combination of grapefruit seed extract and geranium essential oils on burn dressing showed a high level of antibacterial activity against Epidemic methicillin-resistant S. aureus (EMRSA 15). Kavanaugh and Ribbeck (2012) found that essential oils of cassia, Peru balsam, red thyme were found to be effective against a strain of Pseudomonas aeruginosa that is resistant to both oxicillin and methicillin. Used properly, some essential oils may be a good choice for disinfecting surfaces in your house because they could potentially kill off some of those nasty "superbugs".
  • Buy antibiotic free meat and dairy when possible. Guess where 80% of the antibiotics in America are used? Are you sitting down? Livestock and agriculture. Along with treating infections in frequently sick animals, antibiotics are also used to promote the growth of food animals.  Use of antibiotics in livestock is actually the biggest problem with antibiotic resistance. Despite the public health threat, regulation of antibiotic use for livestock within the United States is pretty much non-existent. The CDC is working on education programs, but at least right now, there is no legislation about how to use antibiotics for livestock. We can still vote with our money though and choose meat and dairy that are antibiotic free as much as possible.
But take heart. Statistically speaking, antibiotic resistance isn't the most deadly thing you'll encounter in your day. Receiving care at a hospital could put you at risk for the third leading cause of disease in the United States- medical errors. But even before that there's cancer (no. 2) and heart disease (no. 1).

DDT Is Not A Magic Bullet

Taken from a forum post I wrote for my from my Environmental Health Class. I was deeply disturbed at how my classmates were consistently in favor of the use of DDT in developing nations, even when confronted with research showing that mosquitoes would become resistant and that it was ineffective at eliminating malaria in developing nations:

I have been inclined to believe that it is not a good idea to reintroduce DDT because of its hazards. The fact that it has been banned in the United States indicates that there must have been significant adverse effects. However, I believe that forming a truly informed stance requires looking at both sides of an issue and seeking out information that may undermine  my current stance on a subject. So I went looking for articles on the benefits of DDT and why it should be used against malaria in places like Africa. A couple of examples of articles supporting DDT that I found were “Thirtieth Anniversary Of Misguided Ban On DDT Without This Pesticide, Millions Die Of Malaria, Says Health Group; Senate To Extend Ban” by the American Council on Science and Health (2002) and “What the World Needs Now is DDT” (Rosenberg, 2004). The main arguments I found supporting the use of DDT were as follows:
  • DDT is very effective at eliminating malaria and is responsible for the elimination of malaria transmission in the United States and other countries.
  • There is no evidence that DDT poses harm to humans, while malaria is a serious health threat known to take many lives.
  • DDT is the most cost effective way to eliminate malaria in developing countries.
So my next task was to look at each of these arguments and find out what evidence there was for and against them. So starting with my first bullet point:

DDT is very effective at eliminating malaria and is responsible for the elimination of malaria transmission in the United States and other countries. DDT is very effective at killing mosquitos and it was a big part of the malaria elimination campaign in the United States. I think the issue is whether DDT is the most crucial component of malaria elimination. Much of malaria elimination campaign in the United States was focused on spraying DDT, but it also included drainage and removal of mosquito breeding sites (Centers for Disease Control, 2012). So while DDT was widely used during the malaria elimination campaign altering the environment to discourage mosquito breeding was also a part of fighting malaria. I know this seems like heresy, but I have to wonder if drainage, better indoor plumbing and sewage systems and the removal of mosquito breeding sites may have actually provided a longer term solution to malaria transmission. After all, DDT hasn’t been used in the United States for decades and we still have mosquitos, but malaria isn’t a serious public health threat here. So just because we used DDT to fight malaria transmission, doesn’t necessarily mean that it was the most effective tool against malaria or that it will save Africa from malaria without other efforts like drainage and sewage control. Moving on to the next point…

There is no evidence that DDT poses harm to humans, while malaria is a serious health threat known to take many lives. People usually take this to mean that something is proven to be safe, but that’s not what “no evidence of harm” means. “No evidence of harm” was the same strategy used to convince the public that tobacco didn’t increase the risk of cancer and that the use of lead in gasoline, plumbing and paint was benign. “No evidence of harm” can simply mean that no studies have been done on the effects that a substance has on humans. In reading through the report on DDD, DDE and DDT from the Agency for Toxic Substances and Disease Registry (ASTDR), I found that for many side effects on humans and animals there were simply no known studies available.

For example, in relation to the effects of DDT and its related compounds DDD and DDE on kidneys, the report says “No studies were located regarding renal effects in humans after oral exposure to DDT, DDE, or DDD.” This doesn’t mean that DDT has been proven to be safe for human kidneys, it just means that there aren’t any studies that have looked at that aspect yet. If DDT is harmful to the human renal system, not having any studies won’t actually change its toxicity; all it means is that studies haven’t been conducted on it. (However, studies on rats have shown some adverse effects to rodent kidneys.)  

The report does cite some studies which have shown a higher incidence in lung cancer to some workers who are exposed to DDT and others showing elevated levels of liver enzymes with high exposure. DDT is known to cause adverse neurological effects in both humans and animals, though as the report states, “Few studies have explicitly evaluated neurotoxicity in humans following chronic exposure.” Again, it doesn’t mean that DDT has no neurological effects on humans at chronic exposure levels, simply that there is very little research on the subject. According to the report from the ATSDR, DDT is known to cause harm to the endocrine and reproductive systems of animals and there is research pointing to immunological damage as well.

But for the sake of argument, let’s assume that DDT is only harmful to animals and will eliminate malaria transmission without extensive work on sewage and drainage systems or other measures. Does this make it a good strategy for malaria control in humans? I think to answer this question we need to consider how far we really can remove ourselves from the health of the environment. If the water, air, plants and animals around us are damaged from toxic chemicals, will we really be spared any ill effects? I think this question is especially relevant when we are talking about about Sub-Sahara Africa where many people still rely on subsistence farming. 

Also, Sub-Sahara Africa is home to many rare and endangered plants and animals. If DDT is used in these countries and it does eliminate malaria transmission, will it cause more trouble by damaging the land and animals? If people rely on the health of their cattle, pigs and chickens to sustain them and these animals become sick and can’t reproduce, we might be looking at a situation where people could suffer further from poverty, malnutrition and starvation. Because DDT persists for long periods of time in the environment, if it is used in areas with rare and endangered species it could cause irreparable damage to the ecosystems of these places. And heading into the homestretch on what has become a near treatise at this point…

DDT is the most cost effective way to eliminate malaria in developing countries. The issue of DDT and malaria elimination gets at the heart of a lot of issues about what it means to actually help people in developing countries. If you think about it, we are presuming a lot when we in America discuss how to solve a problem in another country with a different culture thousands of miles away. 

Mosquito nets are an example of another strategy that is popular with Westerners as a way for people in Africa to fight malaria, but in some areas malaria is so common and most cases go away on their own that most people don’t even consider using a mosquito net. Sonia Shah (2010), author of The Fever: How Malaria Has Ruled Humankind for 500,000 Years, compares malaria in these regions to the flu in North America- it can kill, but many recover without ill effects. She compares mosquito nets in these areas to face masks in cold and flu season. If you handed out free face masks to everyone in your neighborhood during cold and flu season to wear every time they go out in public, how many people would wear them, even if it would stop transmission of the disease? And even if everyone used a mosquito net, the nets wear out and need to be replaced, so they’re not a long term solution. I think the issue of DDT is much the same way. We used DDT as did many other countries, and so we assume that developing nations should too. But it may not be the best answer for them.

I think Shah really sums it up best when she writes, “Perhaps what we need is a whole new approach. Instead of masterminding solutions for distant problems and then handing them down from on high — as we do not just in our anti-malaria efforts but in a variety of aid programs aimed at extreme poverty — we should empower the poor to come up with their own solutions, and then help figure out how to implement them. Such a process might not lead to grand, magic-bullet solutions. More likely, we'd get micro-solutions, variable from locale to locale, from village to village. But we'd be supporting self-reliance and building goodwill along the way. And we'd surely avoid the wastefulness — and really, the affront — of befuddling communities with "gifts" that many neither want nor use.” 

While she is referring specifically to mosquito nets and malaria, I think the same applies to DDT.
Also, mosquitos may be carriers of disease, but they are also part of the eco-system as are any naturally occurring pathogen or pest, whether it be viruses, bacteria, fleas or rats. The idea of DDT is that if we can kill the mosquitos we can stop the spread of malaria. But here’s the thing, mosquitos have been on the Earth for tens of millions of years. In order to do that they have had to be pretty adaptable and even with their primitive biology they are already starting to outsmart us. In some areas, cases of DDT resistance has been reported in mosquitos (Dasgupta, 2012).

DDT is not a magic bullet. If DDT is employed for malaria control, it should be used with extreme caution and to a minimum to prevent resistance and side effects, much like antibiotic stewardship. Dasgupta’s (2012) conclusion from the World Bank’s blog sums it up better than I can: “Continued use or reintroduction of DDT in malaria control should call for a careful country-by-country assessment of costs and benefits based on a country’s circumstances. Other vector control measures, such as larvicidal and environmental management may also be -necessary - when appropriate - based on scientific evidence.”

References
Agency for Toxic Substances and Disease Registry (n.d). DDT, DDE and DDD: Health effects. Retrieved from http://www.atsdr.cdc.gov/toxprofiles/tp35-c3.pdf

American Council on Science and Health Staff(2002, June 12).  “Thirtieth Anniversary Of Misguided Ban On DDT Without This Pesticide, Millions Die Of Malaria, Says Health Group; Senate To Extend Ban”. Retrieved from http://acsh.org/news/2002/06/10/thirtieth-anniversary-of-misguided-ban-on-ddt-without-this-pesticide-millions-die-of-malaria-says-health-group-senate-to-extend-ban

Centers for Disease Control and Prevention (2012). Elimination of Malaria in the United States (1947 — 1951). Retrieved from https://www.cdc.gov/malaria/about/history/elimination_us.html

Dasgupta, Susmita (2012, October 23). “Health costs and benefits of DDT use in malaria control and prevention.” Retrieved from http://blogs.worldbank.org/developmenttalk/health-costs-and-benefits-of-ddt-use-in-malaria-control-and-prevention

Rosenberg, Tina (2004, April 11). What the world needs now is DDT. New York Times Magazine. Retrieved from http://www.nytimes.com/2004/04/11/magazine/what-the-world-needs-now-is-ddt.html?_r=0

Shah, Sonia (2010, May 2). In Africa, anti-malaria mosquito nets go unused by recipients. Los Angeles Times. Retrieved from http://articles.latimes.com/2010/may/02/opinion/la-oe-shah-20100502

This post was inspired by a bathroom door in a California State Park

We decided to visit a state beach and I had to the use the bathroom, which was (of course) something less than luxurious. There was a lot of graffiti on the door, but the most prominent was scrawled in permanent marker stating: "Hope you had your Hep C shot". A more enlightened soul wrote beneath it "You can't get Hep C from a toilet". It's a good thing I didn't have a writing implement on me or I would have further defaced state property and written in large letters: "THERE IS CURRENTLY NO VACCINE FOR HEPATITIS C".

I have heard a lot of very interesting stories lately about disease transmission and prevention. The vandalism in the bathroom was just the proverbial straw that broke the camel's back. So to the set the record straight, here are a few facts:

Immunity- Immunity can be defined as "The condition of being immune, the protection against infectious disease conferred either by the immune response generated by immunisation or previous infection or by other nonimmunologic factors." Since immunity is a condition of the body characterized by the immune system's ability to recognize and mobilize a response to fight off an infection, it is based on an individual's health and previous infection status.

For the most part, you can't transfer your immunity to someone else because immunity depends on whether their immune system will recognize a particular antigen. One exception is breastfeeding because the antibodies from the mother's bloodstream can transfer through her milk to her baby. But you can't get a vaccine and pass the immunity it gives you to someone else- no matter what this column in Popular Science says about the oral polio vaccine in developing countries. (I'm still in awe that this sort of thing was published. You can't pass your immunity to others and thereby strengthen the whole community. If that were the case there would be no need for high vaccination rates. Face+palm.) Other people would have to either acquire and recover from the infection or receive a vaccine to stimulate their immune systems to fight off an invading pathogen.

It also means that a vaccine is specific to a certain antigen. You can't get a vaccine designed to create immunity for one disease and have it work against something completely different- which is where this news story gets off track when it claims that a flu vaccine would have saved this boy when he was infected with both flu and the deadly MRSA bacteria.

Herd immunity- Herd immunity is the idea that when a high level of vaccine coverage is reached (somewhere between 80-99%), that a particular illness will no longer strike a population and that this will protect those who can't or won't be vaccinated. Of course, levels need to be high- which is why the assertion that genital warts infections on the decline from the HPV vaccine is questionable. Low rates of coverage, by definition can't confer herd immunity. However, other factors could have influenced the decline of genital warts infections like the advent of federal support for comprehensive sex education programs which occurred around the same time. Herd immunity also means that if the CDC is correct about the efficacy of flu vaccine (50-60% most of the time), even in a good year we won't be able to achieve herd immunity, so please be careful with young babies and the immunocompromised.

Asympotmatic transmission/non-classical symptoms- You have to be very careful when you are around anyone immunocompromised or very young or old because vaccinated individuals who do contract an illness may not display classical symptoms (i.e. symptoms you would see in an individual who is not vaccinated who contracts the disease). Pertussis (commonly known as "whooping cough") is one of these. Vaccinated individuals who develop pertussis often don't display the "whooping" cough or may be completely asymptomatic. Measles is another. Vaccinated individuals who contract measles often don't have a rash, but may have a stuffy nose and general malaise. (This is called modified measles.) 

How often does this happen? Well, it's hard to say. (After all, how often do you go into your doctor or pediatrician and say, "Even though nothing appears to be wrong, could you please run a complete set of tests to make sure that it's not a case of non-classical pertussis or modified measles?") A few years ago a survey taken during a pertussis outbreak in California showed that in 9 counties between 44 and 83 percent of the pertussis cases were in vaccinated individuals. The Journal of Emerging Infectious Diseases has study from Israel where a very young baby died of pertussis contracted at a daycare center where all the children and staff were fully vaccinated. Some of the children who tested positive for pertussis did not meet the WHO's diagnostic criteria for the disease, yet still had it. The Journal of Infectious Diseases contains an article on two fully vaccinated doctors who had measles without the rash- the only reason that anyone considered testing them is because they had both been exposed to the disease. We do know that even individuals with non-classical presentation can pass the virus. It does happen, but on a wider scale it's hard to quantify. So  the PSA is please exercise caution at all times.

Vaccine schedule- A vaccine schedule is what shots you get when. Here in America, I think we kind of assume that our vaccine schedule given by the American Academy of Pediatrics is the "gold standard". There actually is no one vaccine schedule that has been agreed upon to be the "best". The AAP's schedule is pretty similar to Canada's and Great Britain's, though there are some notable differences.

In Great Britain, they don't routinely vaccinate for varicella (chicken pox) because when the varicella virus is not present, it increases the chance of older people developing shingles. If you take a look at the vaccine schedules throughout Europe, you'll find that it's a mixed bag. In some countries tetanus is recommended only for at risk populations. In several first world countries like France, Italy, Ireland, the Netherlands and Germany they don't have rotavirus on their schedules (as of 2010). Varicella is absent from many countries vaccine schedule. Other countries add in diseases that are of special concern to them like Japanese encephalitis in many Asian countries. In the United States, there is kind of a philosophy that if there is even a relatively small risk for a disease, that we should err on the side of vaccinating for it. In other countries, a disease that has a relatively minimal risk may be viewed as having little upside for routine vaccination.

So why do we vaccinate for all these diseases, how do they spread and how do the vaccines impact transmission? Well, this isn't an  exhaustive list, but here are a few. You may get a few surprises...

Tetanus- I've heard the wildest stories on when you need a tetanus shot. If you scrape your hand on a metal locker backstage in an auditorium, if you get a small cut from a nail holding down carpet inside a house, if you cut your hand on glass in your kitchen sink. One mom told me that after her child got a really bad scratch from a cat, she was told by a doctor at the ER that her kid needed a tetanus shot. All of the above scenarios are extremely unlikely to even impossible to lead to tetanus. Here's why: Tetanus is caused by a bacteria called clostridium tetani. It lives in the feces of animals and flourishes in wet, warm and environments, especially like pastures. It causes infection when it enters the bloodstream through a deep wound. So rust and nails or other metal objects  actually have nothing to do with the infection itself. A rusty nail is a sign that the environment could be wet enough for the bacteria to flourish and stepping on one could cause a deep puncture wound that introduce the bacteria into the bloodstream. It's not a communicable disease.

Polio- Quick: who invented the vaccine that is credited with eliminating polio? You said Jonas Salk didn't you? Scientists and researchers now believe that it was a combination of Salk's inactivated polio vaccine (IPV- the one you get through a shot) and Sabin's oral polio vaccine (OPV- sugar cubes). (And depending on who you talk to, they might even give more credit to Sabin.) Salk had better backing because of his connection with Basil O'Connor, head of the National Foundation for Paralytic Polio (now the March of Dimes). Another reason the OPV has fallen off the radar in the US is that it was taken out of circulation in this country in 2000 because of vaccine acquired paralytic polio. In other countries, they still favor the OPV because the risk of provocative polio. (Provocative polio is when something like an injection or surgery during the high season for enteroviruses increases the chances of developing polio.)

Measles- Yes, this one can actually cause death, but who is most at risk may be a little surprising. According to the CDC, approximately 450 people used to die annually of measles in the pre-vaccine era. (Comparable to the number of people who die of salmonella poisoning annually.) Diagnoses of measles have been on the decline since the advent of the measles vaccine, but now those who do get it are more likely to die. The vaccine campaign has targeted young children, but adults (especially over age 30) are much more likely to develop complications or die. (The other group at greater risk are those with HIV/AIDS because they have compromised immune systems.) The other thing that may surprise you is the role of vitamin A in preventing complications with measles. The WHO recommends that all cases of measles be treated with vitamin A.

Mumps/Rubella/Varicella- Wow, wow, wow. I can not believe the number of times I have heard people say that massive numbers of children used to die from mumps and rubella. Mumps and rubella were actually not added to the vaccine schedule because of a high risk of death in children. In fact the WHO classifies, both mumps and rubella in as mild illnesses in children- it's adults that tend to be the actual concern. They were actually added into the vaccine schedule because in teenagers and adults they can cause reproductive harm.

 In adolescent boys, mumps can sometimes infect the testicles causing impaired fertility. Deafness is another rare side effect of mumps, again more common in adults. Rubella itself isn't the concern, it's congenital rubella syndrome (CRS) that causes disability and sometimes even death. If a pregnant woman contracts rubella she can potentially pass the disease onto her unborn child and it can cause problems like blindness, deafness, developmental delays, and heart malformations. Varicella (chicken pox) is again a generally mild illness in children, but can be deadly especially for the immunocompromised. For women who do not have immunity, contracting varicella during the first 20 weeks of pregnancy carries a small risk of birth defects called congenital varicella syndrome.

Hepatitis B- I hear people say that you can be picking up trash along the side of the road for a service activity, get stuck by a stray drug needle, develop hepatitis B and then DIE. This is not an accurate reflection of the transmission pattern of hepatitis B. Though there are a few very, very rare exceptions, hepatitis B is primarily transmitted in three ways: sharing needles during illicit drug use, high-risk sexual behaviors and maternal transmission either at birth or in the first few years of life. The good news is that in adults, 90% of hepatitis B infections will clear on their own without any complications. But for children it can lead to a chronic infection and possible further complications.

Overall, there are relatively few children who have hepatitis B. Child-to-child transmission is well documented in developing countries, but among developed nations child-to-child transmission of the infection is extremely rare. Because of the possibility that a mother could be carrying the disease and not aware of it, it has been added to many vaccine schedules.

Rotavirus-This story definitely paints a sensational picture of rotavirus, but it's on the melodramatic side. In developing countries, diarrheal illnesses are a significant source of mortality because of malnutrition, dehydration, and lack of access to healthcare. However, in the US and other developed countries, the goal of rotavirus vaccination is actually to reduce hospitalizations due to severe rotavirus. However, there is a trade-off because some rotavirus vaccines like RotaTeq carry an increased of gastrointestinal illness over no rotavirus vaccine- though hospitalization is statistically less likely.

Alligators, Parking Lots and International Health Initiatives

We stayed at a hotel in Florida a little while ago. It was next to a forested lot with a canal surrounded by a high chain link fence. One d...