The Trouble With Some Microbes . . .

7 02 2013

Our battle against bacteria is tilting in our favor. After all, we have vaccines and antibiotics on our side. That doesn’t mean we can get cocky. It’s tilting, not surrendering at our feet.

But we’re still struggling to find ways to kill viruses once they’ve infected us.  At best, we can sometimes control them.

Although we can kill viruses on our bodies and other surfaces with disinfectants, it’s difficult to kill them when they’re living inside our cells.  When we’re infected with a virus, it takes up residence in one of our cells and uses the cell’s machinery to reproduce itself.

Developing a drug that will kill the virus without disrupting the intracellular machinery of uninfected cells is no easy task. It’s like playing Jenga—eventually the whole structure will collapse.

Bacteria, on the other hand, generally live outside of our cells and are easier targets.

There are some bacteria that have developed a resistance to not just one drug, say for instance penicillin, but to many such drugs.  They’re known as multi-drug resistant microorganisms such as streptococcus pneumoniae and mycobacterium tuberculosis, germs that we thought were very much under control and are now surging back into the population.

One major factor in preventing us from understanding the world of microbes is the size of that world.

The folks at the University of Georgia College of Agricultural and Environmental Sciences put bacteria into perspective this way, “Bacteria vary somewhat in size, but average about 1/25,000 inch.  In other words, 25,000 bacteria laid side by side would occupy only one inch of space.  One cubic inch is big enough to hold nine trillion average size bacteria—about 3,000 bacteria for every person on earth.

“Bacteria make up the largest group of micro-organisms.  People often think of them only as germs and the harm they do.  Actually, only a small number of [the thousands of different] bacteria types are pathogenic (disease-causing).  Most are harmless and many are helpful.”

Neal Rolfe Chamberlain, professor at the Kirksville College of Osteopathic Medicine, explains viruses in this manner, “Viruses are very small forms of life.  In fact, people still argue over whether viruses are really alive.  Viruses range in size from about 20 to 300 nanometers (nm).  A nanometer is 0.000001 of a millimeter.  A millimeter is 1/25 of an inch.  So in other words, you can place 25,000,000 nanometers in an inch.  If the biggest virus is 300 nm then you could fit 83,333 of that virus in an inch.

“Viruses are major freeloaders.  They cannot make anything on their own.  To reproduce they must infect other living cells.  Viruses infect bacteria, parasites, fungi, plants, animals, and humans.  No one escapes them.  If you have had the flu, chickenpox, measles, a common cold, mono, a cold sore, or a sore throat you have been infected by a virus!”

Some viruses, like HIV and hepatitis C, tend to develop strains that can resist mono drug therapy (treating the patient with one drug at a time).  We have to try and control the viruses with combination, or “cocktail” drugs (treating the patient with several drugs at once), although even that approach does not always work.  Some viruses can keep mutating until we’ve run out of drugs to try.

All this is to say that fighting microbes is seldom a simple task, and seemingly one that is neverending. For example, we have a whooping cough vaccine, but new strains are popping up and new vaccines are needed for this astoundingly infectious microbe.

We will never be rid of our tiny co-inhabitants on this world, and anyway, most of them we want to keep around. It’s those others . . . wouldn’t it be nice to have a jail for nasty microbes?

By PKIDs’ Staff





Reporters – Follow The Science (Please!)

12 12 2012

Immunizations are a perpetually hot topic. We’ve been getting questions from reporters for over a decade about the need for vaccines, the efficacy of vaccines, and invariably the safety of vaccines.

Reporters have been doing stories on vaccines for a lot longer than a decade, but I remember 1999 as the year that things kicked off on the national scene. The television program ‘20/20′ ran shows featuring parents who claimed that various vaccines caused SIDS, multiple sclerosis, autism, and a variety of other illnesses in themselves or their children.

All these years later, when study after study after hundreds of studies have proven the safety of vaccines, many reporters still insist on representing the “other” side of the story when the subject is vaccine safety.

When I get a call from a reporter asking to speak to a parent whose child has been affected by a vaccine-preventable disease, I ask if they are also speaking to parents who believe their child has been adversely affected by a vaccine.

The answer is always yes.

The reporter will say that he or she just wants to present a balanced story.

After all of these years, and after all of these studies, I can’t help but wonder what their definition of balanced may be.

When I read a story about the importance of wearing a helmet when riding a bicycle or a motorcycle, there is often included in the story an anecdote about someone not wearing a helmet while riding who was consequently harmed by the lack of said helmet.

Never, in the same story, do I read about riders who were saved from harm by not wearing helmets, although I’m sure there are people in this world who believe it is safer to ride without helmets. For some reason, reporters don’t feel the need to present the anti-helmet point of view in order to have a balanced story.

The use of seat belts in cars has been mandatory in all states since the 1980s. When writing about car accidents, reporters frequently include stories about the injuries sustained when so-and-so was not wearing a seat belt.

I don’t believe I’ve ever read such a story where the reporter also highlighted incidents of those saved from harm by not wearing seat belts. I know of at least one person who firmly believes that not wearing a seat belt is safer than wearing one, but I have not yet seen her anti-seat belt view used to provide balance in a car accident story.

Reporters who include opinions from parents who believe their children were adversely affected by vaccines, and who include junk science from those pretending to be scientists, all in the name of having a “balanced” piece on vaccines, simply haven’t done their homework.

They are behind on the science, and the stories they write end up creating fear and confusion on the part of parents.

If a reporter feels that it is important to present views not substantiated by science, they should do an opinion piece rather than a news story.

At PKIDs, we sincerely appreciate those writers who look for and use the facts. As parents of children affected by disease, it’s easy for us to have lab work done and determine by the results that our child is infected with a particular disease.

If there is a vaccine to prevent that particular disease, we can say that it’s probable that, had our child been vaccinated, he or she would not have become infected. But, since not all vaccines work for everyone, we cannot say for certain. We can only talk about what vaccine-preventable diseases have done to our families.

We’re not painting all reporters with the same brush. Many reporters follow the science and come back with a fact-based story.

For those who do not, we ask that you make clear in your next story which parts are unsubstantiated, and which are based on fact.

Let’s stop the unnecessary scaremongering of the public.

 
By Trish Parnell





Why Vaccinate? I Never Get Sick!

5 11 2012

No matter your age, if you’re sitting in a moving vehicle you’re required to wear a seatbelt or to be in a size-appropriate car seat.

Most states require that anyone riding a bicycle or a motorcycle wear a helmet. And again, it doesn’t matter what age you are.

Kids going to public schools are required to be immunized against several diseases for school entry. How many immunizations they’re required to get depends on the state they live in, and the school they attend.

I suppose I could think up a few public health scenarios that would require adults to be immunized against a particular disease. But as a rule, unless our jobs require it, we adults are exempt from this particular requirement.

There are lots of protections in place for kids, as there should be. For instance, if I don’t feed my daughters, or provide adequate shelter for them, they’ll be taken away from me and placed in a foster home, where they’ll get the care they need. We need that oversight in place, so that no kids fall through the cracks. The heartbreak is that there are still kids falling through the cracks, but we do know that the oversights in place keep that number from being astronomical.

Most adults don’t need that kind of micromanagement when it comes to their health. But, they do need information. Before I became involved with PKIDs, I wasn’t even aware that there were vaccines for adults, other than the flu vaccine.

Now I know.

I don’t have time to get sick. I get vaccinated for me. I also wash my hands, try to get enough sleep, make myself eat green vegetables, and generally do whatever I need to do to keep myself healthy. But because I’ve met and talked with so many families affected by preventable diseases and I know how awful those infections can be, one of my motivations for getting vaccinated is so that I don’t accidentally infect someone else.

For example, it’s the infected adults and teens around babies who infect them with whooping cough, and it’s the infected birth moms who infect their newborns with hepatitis B. Babies infected with whooping cough can end up hospitalized, or worse. And babies infected with hepatitis B usually stay infected for life. This can lead to liver cancer or transplantation—if they’re lucky.

If you’re one of those people who never gets sick and figures you don’t need to be vaccinated—well, who knows, you might be right. But not getting sick is not the same as not being infected. You can and do pass on those germs to little babies who haven’t gotten all of their vaccinations yet, and others whose immune systems are not robust, for one reason or another.

So, you know where I’m going with this. Take just a few minutes the next time you’re at the pharmacy or your doctor’s office and ask what vaccinations you need. Do it for you, but also do it for the vulnerable in your life.

By Trish Parnell





London!

9 07 2012

Are you going to London for the OlympicsI lived in Calgary when the Games were held there. It’s chaos and fun and nothing like you’d expect, if you’ve never been.

You’ll meet people and germs from scores of countries—about 11 million people, to be specific, and each one teeming with his or her own microbes. Olympics health director Brian McCloskey says they’re ready to go and will be on the lookout primarily for GI bugs “and infectious diseases such as measles.”

Want to bring home souvenirs that won’t make you sick? Use this CDC piece as a checklist on staying healthy in London during the Olympics:

Be Up-to-Date on Your Jabs

Some illnesses that are very rare in the United States, such as measles, may be common in other countries. Make sure that you and any children traveling with you have had all shots. Even if you had all routine vaccines as a child, ask your doctor if you need a tetanus/diphtheria/pertussis booster.

Watch Out for that Lorry!

In the United States, you’re taught to look left, look right, and look left again before you cross the road. In England, however, they drive on the left side of the road. That means you should always look right, look left, and look right again to avoid stepping into the path of traffic driving on the left.

Get Thee to an A&E

If you get hit by a lorry, don’t call 911, call 999, and don’t ask to be taken to the ER, ask for the A&E (Accident and Emergency). Only call 999 in the event of a serious illness or injury. For cuts and scrapes, muscle strains, or minor illnesses, visit a pharmacy or walk-in center (no appointment needed). To find a pharmacy or walk-in center, visit www.nhs.uk/London2012  or call 0845-4647.

Note that the health insurance that covers you in the United States probably won’t cover you while you’re overseas, so you may have to pay out-of-pocket for any care you receive in London. Consider purchasing travel health insurance that will reimburse you for any costs you incur.

Go on Holiday (But Not from Healthy Habits)

Have a great time in London, and make sure you take your healthy habits with you:

  • Always wear a seatbelt.
  • Wash hands frequently, or use hand sanitizer.
  • Cough and sneeze into a tissue or your sleeve (not your hand).
  • When outdoors during the day, wear sunscreen, stay hydrated, and seek shade if you get too hot.
  • When indoors or at large events, know where emergency exits are.
  • If you drink alcohol, do so in moderation.
  • Use latex condoms, if you have sex.

Speak Like a Native

Some terms, including health-related terms, differ between British English and American English. Be familiar with these to avoid confusion if you need medical care.

British English/American English

  • A&E (Accident and Emergency)/ER (Emergency Room), ED (Emergency Department)
  • Chemist/Pharmacist
  • Consultant/Attending Physician
  • Giddy/Dizzy, Unbalanced
  • Gip (“My back is giving me gip.”)/Aches, Pains (“My back hurts.”)
  • Holiday/Vacation
  • Jabs/Shots, Vaccinations
  • Lorry/Truck
  • Loo/Restroom
  • Paracetamol/Acetaminophen
  • Plaster, Elastoplast/Elastic Bandage, Band-Aid
  • Surgery/Doctor’s Office
  • Surgical Spirit/Rubbing Alcohol

More Information

Thanks to CDC for excellent info, as always.

Image courtesy of Flickr user kh1234567890





Ask Emily

26 04 2012

What’s the deadliest infectious disease ever and what currently is the most deadly infectious disease?

The answer to this question is more complex than simply counting up numbers of people who die from infection. For example, diseases like measles and smallpox have proved to be far deadlier in some populations—such as Native Americans—than in others, because of population differences in disease resistance.

Another variable is intensity of the illness a pathogen causes. Influenza comes in many forms of virulence, and as the Spanish flu pandemic of the early 20th century made clear, even that virulence can vary depending on specific population features; the Spanish flu, which took an estimated 50 million lives, killed the young most relentlessly.

Even an individual disease vector can wax and wane in terms of how virulent it is or which tissues it invades. For example, Yersinia pestis, the bacterium responsible for the infamous Black Death that swept through Europe in the 14th century, may vary over time in its virulence and is far more deadly when transmitted as an aerosol to lung tissues than when it invades the lymph and causes the bubos that characterize it.

Another issue is, how do we calculate “deadliest?” Is it in terms of sheer overall numbers, or do we calculate it in terms of how many people it kills among the number infected? For the sake of addressing this question, let’s talk about both.

Historically, in terms of sheer numbers, the deadliest diseases were smallpox, measles, tuberculosis, plague (e.g., the Black Plague), and malaria. According to a handy Website, the Book of Odds, which calculates odds for us, measles has killed about 200 million people worldwide in the last 150 years and still kills hundreds of thousands in the developing world. Thanks to vaccines, the odds of contracting measles in the United States today are very low unless you are an unvaccinated person living in areas where vaccine uptake is low.

The story on smallpox is similar—it may have killed more people by percent or sheer numbers than any other infectious disease in history, including 300 million in the 20th century alone by some estimates. Yet smallpox as an infectious disease no longer exists thanks to its total elimination through vaccine campaigns.

Thus, along with the plague, smallpox and measles have, for millennia, been the historical killers of humans and would still be among the deadliest infectious diseases today were it not for vaccines. What we have left are some old killers on the list—tuberculosis and malaria—and a newer entity, HIV, the virus that causes AIDS.

We have yet to develop efficient vaccines against any of them. According to USAID, in terms of absolute numbers of deaths, AIDS kills the most people each year, with 2.8 million AIDS-related deaths in 2004, followed by tuberculosis and malaria.

Indeed, AIDS and tuberculosis are often co-conspirators in death, as infection with the HIV virus makes people 20 to 30 times more likely to develop active TB with TB infection. Research for vaccines against HIV and malaria has been feverish but as-yet incompletely successful, one reason these diseases remain the top global killers.

But what about the deadliest disease in terms of how many of infected people die? In the absence of effective treatment, HIV might be one candidate. But the ones that come first to mind are the viruses that cause fast-moving hemorrhagic fevers, such as the Marburg or Ebola viruses.

The Marburg virus, named for the location of the first outbreak and a virus that may reside without symptoms in fruit bats, has caused death rates as high as 90% in some areas, although the average is 23–25%. It is a filovirus, in the same viral family as the five Ebola viruses. One of the Ebola viruses, Ebola-Reston, is perhaps the most notorious of the hemorrhagic fever viruses, having led to death rates as high as 89% in outbreaks.

A near-100% mortality rate is about as deadly as an infectious agent can be if that’s the measure of “deadly” we’re using.

By Emily Willingham

Image courtesy of Wikimedia Commons





Brady’s Life

16 04 2012

Kathryn shares the story of her son Brady’s life, and his ferocious battle with pertussis.

Listen now!

Right-click here to download podcast (14 mins/7mb)





The Parasitic Implications of Raccoons in Your Backyard

2 04 2012

The re-wilding or “greening” of urban and suburban spaces has been an indefatigable trend in urban planning for the past two decades. We like accessible parks and community gardens and food forests and stately trees to go along with our car-filled cities.

One of the charming/troubling manifestations of this trend can be rodents, coyotes, foxes, opossums, and raccoons joining the ‘hood.

Let’s talk raccoons. The bandit-style masking covering their faces, their insatiable curiosity, and nimble human-like hands have popularized them as mischievous varmints. Though their nocturnal habits tend to keep them out of the sights of most of us, they can be unseemly guests with their destructive tendencies. All that these small mammals need is a permanent water source, an enclosed setting for their den, and access to food. Luckily, they can find all these things and more when living in suburbia and cities. Human dwellings and activities serve as both a den reservoir and food source; we are nothing but extraordinarily generous, unwitting hosts.

They can eviscerate lawns in their search for earthworms and grubs, steal your invaluable rubbish from trash bins, suck dry bird feeders, and shred the ventilation ducts, sheetrock and insulation in attics. So cute! In addition, they are hosts to diseases that can kill you. Like rabies. And baylisascariasis.

Baylisascariasis describes the human infection with the raccoon roundworm Baylisascaris procyonis. The parasite is endemic in raccoons, with infection rates ranging from 72% to 100% (1)(2).

If you live in a place with sidewalks, there are most certainly infected raccoons living in close proximity to you; B. procyonis is the pathogen hiding in your backyard (3). One of the larger parasitic worms out there, this big guy inhabits the intestinal tracts of raccoons and produces thousands of eggs that are shed in the feces.

Like humans, raccoons can be fastidious about their pooping habits. They make communal latrines that can be found on natural or artificially flat surfaces—at the bases of trees and in branch crotches, on woodpiles, along and on the top of fences, on roofs, attics, and sandboxes (2).

This results in a condensing and localizing of the eggs in one specific spot, attracting foraging birds and small rodents to undigested seeds and the like, and successfully ensuring the continuation of the parasite’s life cycle as it infects and kills the intermediate host.

The raccoon scavenges the dead, becomes infected with the larva, and the parasite keeps marching on into life cycle infinity.

Raccoons sharing your living space, whether in the attic above you or in a nearby tree or under the porch, means that there’s a raccoon latrine near you; thankfully, they’ve kindly kept all their crap in one place, unlike some roommates I’ve had the pleasure of co-habiting with.

A 2009 survey checking out an area of suburban Chicago close to a marsh and forest preserve found that 51% of lawns had a raccoon latrine (4). This kind of work suggests that there’s a good chance of fecal contamination in many of our backyards, spaces that typically serve as children’s play areas. The uniqueness of the latrine itself—piles of feces with undigested seeds, berries and bones—can also attract curious toddlers. Alternatively, if raccoons occupy chimneys, infective feces can settle within and around fireplaces, contaminating the home.

How is it that this random raccoon parasite can make it onto a child’s fingertips, aside from the obvious hand-to-mouth behavioral sequence most parents are familiar with? There are three major ways this happens. One is that the raccoon can defecate prodigious amounts of B. procyonis eggs, on the order of a million a day. The other is that the parasite’s egg is unbelievably hardy and damn near resistant to all of our arsenals against eradicating grime, schmutz and filth. The egg has four shell layers and is resistant to high temperatures, strong acids and bases, oxidants and reductants, and protein-disrupting agents (2). Guys, that’s pretty much all we got in terms of dealing with dirty surfaces and buggies, and it’s resistant to all of them except for applying direct flames to the egg. And how often do you find yourself planning to incinerate your backyard, aside from Fourth of July celebrations? Lastly, the eggs are remarkably sticky, gluing themselves to available surfaces, which may include toys littered in the backyard.

Once hatched from the egg, the larva has a cruel propensity for the cranial region of their intermediate hosts and, as such, its carousing in the head and thoracic region has grim neurological implications. In fact, the parasite is the most common cause of larva migrans—larval worm migration in bodily tissues—in animals and can produce severe neurological larva migrans (NLM) in over 100 species of birds and animals (1).

That these alarmingly large adult worms produce sizable larva also bodes poorly for us humans. The immensity of these worms can cause significant tissue trauma, especially in young children. The most common diagnosis from infection is eosinophilic meningoencephalitis, in which the brain and spinal cord and the meninges membranes surrounding the two become enormously inflamed due to the larva activating a type of white blood cell known as an eosinophil.

Clinical symptoms can develop two to four weeks after initial infection (5). Usually children have been lethargic, feverish and a little “off” for a few weeks before being rushed to the emergency room with seizures, unsteady gait, or abnormally regressive behavior. There is no commercial test to confirm antibodies to the infection, making it difficult to have an accurate diagnosis (6).

Meningoencephalitis is an affliction whose originating cause can be tough to track down; there are numerous other larval worms to cross off the list before making a diagnosis (including Toxocara canis, Ascaris lumbricoides, as well as species of Angiostrongylus, Ancylostoma, Taenia and Echinococcus).

The infection is not well known to many clinicians outside of the infectious disease field, which can complicate proper treatment of the symptoms (6). In the emergency room, the most pressing need is to control the damaging inflammation, not figure out which worm is the culprit.

Children are more likely to suffer devastating effects of this infection than adults due to their relatively smaller brains (2). Infection outcomes have been statistically grim—many of these young patients either suffer permanent neurological and ocular defects or death. A microbiology paper from 2005 puts it bluntly, “To date, all survivors have been left in a persistent vegetative state or with severe residual deficits”(1).

And the victims are mostly very young children, typically boys. Infants and toddlers are predisposed to learn about their world by oral contact and commonly engage in pica and geophagia (eating of dirt). These types of behaviors can also be demonstrated by older children with developmental disabilities, another important subset of patients that have become infected with the parasite (3). Overall, important risk factors for baylisascariasis infection include exposure to raccoon feces, pica or geophagia, age under 4 years, male gender, and intellectual development delay.

Thankfully, the number of cases is low, but it’s hard to discern whether that’s attributable to an actual low incidence of disease or a lack of reporting. Many parents decline autopsies, the only true way to identify a case of baylisascarisasis.

I tracked down 22 cases that have been reported in the literature (1)(3)(6)(7)(8)(9). Subclinical infection may also occur—a Chicago study found that 8% of children showed antibodies to the parasite though none had ever shown symptoms of disease (10); baylisascariasis may be much more prevalent than we think.

The number of reportable cases has been steadily rising in the past decade for unknown reasons, though I suspect that the greening of our surroundings and the increase in diagnosed autism cases, a medical situation that can predispose children to pica habits, may have something to do with it.  Most recently, adult B. procyonis worms have been detected in pet dogs (2). This worrisome finding suggests that cases could continue to rise.

There are few wild animals that live so freely alongside humans that are cable of transmitting such a ferociously nasty and fatal disease. Parents and communities should be made aware of the dangers of having such animals close by and should go to efforts to locate and remove any raccoon latrines within or near the home.

Bringing nature to the neighborhood isn’t always a deliberate process, like revitalizing our neighborhoods by putting in a park or planting some trees. Industrial decay, environmental catastrophes and housing foreclosures can transform our urban landscape into a more inviting setting for nature to recolonize our space. Bobcats have been found living in foreclosed homes, neighborhoods in New Orleans are literally turning into marshland, and feral animals prowl through Detroit. One of the benefits of living in a city, away from nature, is that the only animals we have to deal with are ourselves.

References
(1) Gavin PJ, Kazacos KR, and Shulman ST. (2005) Baylisascariasis. Clin Micro Rev. 18(4): 703-18
(2) Gilbert CE (Date unknown) Concern with Communicable (Infectious) Diseases of Raccoons. Epidemiology and Toxicology Institute, LLC.  Accessed online March 27, 2012.
(3) Hajek J et al. (2009) A child with raccoon roundworm meningoencephalitis: A pathogen emerging in your own backyard? Can J Infect Dis Med Microbiol. 20(4): e177 – e180
(4) Page K et al (2009) Letter: Backyard Raccoon Latrines and Risk for Baylisascaris procyonis Transmission to Humans.  Emerg Infect Dis. 15(9): 1530-1
(5) Park SY et al (2000) Raccoon Roundworm (Baylisascaris procyonis) Encephalitis: Case Report and Field Investigation Pediatrics. 106(4): E56
(6) Frank Sorvillo et al. (2002) Baylisascaris procyonis: An Emerging Helminthic Zoonosis. Emerg Infect Dis. 8(4): 355-9.
(7) Moertel CL et al. (2001) Eosinophil-Associated Inflammation and Elaboration of Eosinophil-Derived Proteins in 2 Children With Raccoon Roundworm (Baylisascaris procyonis) Encephalitis. Pediatrics. 108(5): E93.
(8) Haider S et al. (2012) Possible pet-associated baylisascariasis in child, Canada [letter]. Emerg Infect Dis. 18(2): 347-9. Accessible online.
(9) Kelly TG et al. (2012) Spinal cord involvement in a child with raccoon roundworm (Baylisascaris procyonis) meningoencephalitis. Pediatr Radiol 42(3):369-73. Epub 2011 Jun 1.
(10) Pai PJ et al. (2007) Full Recovery from Baylisascaris procyonis Eosinophilic Meningitis. Emerg Infect Dis. 13(6): 928-30

By Rebecca Kreston

Image courtesy of Michigan.gov