01
Aug 2011

Cat Parasite Linked To Brain Cancer In People

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A third of us are infected with Toxoplasma gondii, a parasite that can be transmitted to us by animals. Cats represent a major source of this organism, and are therefore a common route of infection for us since they continually shed the parasite. Consequently we can become infected with Toxoplasma gondii if we come into contact with anything that is contaminated with the organism as a result of a cat’s shedding. Some ways include:

  • Contaminated soil  (when gardening in an area where cats have defecated)
  • Cleaning the cat litter box
  • Contaminated water
  • Undercooked meat (lamb, pork, and venison especially – these animals are infected by cats in the same way as we are)
  • Cooking utensils coming into contact with undercooked, infected meats

Although many people are infected with this parasite, most are unaffected by it, and show no clinical symptoms since the immune system effectively prevents it from causing disease; however, clinical toxoplasmosis can be a real problem for people with weakened immune systems, such as:

  • HIV infected patients
  • Chemotherapy patients
  • Organ-transplant recipients

Additionally, it poses a particular risk for unborn babies. A  woman who comes into contact with the organism for the first time during her pregnancy may transmit it to the fetus in utero, resulting in birth defects or even infant fatalities. Transmission of the parasite to an unborn baby, however, is less likely if the woman has previously come into contact with the organism at least six months or more, prior to becoming pregnant.

Links With Brain Cancer?

Interestingly, a recent study reports a correlation between rates of infection of Toxoplasma gondii, and the incidence of brain cancer. Global data on brain cancer in people from 37 countries was collected and compared with the prevalence of Toxoplasma gondii infection in those regions. The research group reported that brain cancer rates increased in countries where the parasite was more prevalent.

This ecological study, however, merely points to a correlation between the two events – it does not imply that the parasite actually causes brain cancer in people. And certainly the opposite could be true – it’s not impossible that brain cancer could be the driving factor behind Toxoplasma gondii infection.

So as it stands, this report does not prove cause and association, but is predominantly hypothesis-generating, and does provoke scientific curiosity. In the words of one of the authors:“These were the best data available and we felt they were sufficient to take the first step. Working with actual brain cancer patients is an obvious next step, but it would be an expensive proposition.  It is a lot easier to justify the second, expensive step when you have some evidence for the hypothesis. We are hoping that our results motivate others in the field to do further studies.”

Thomas, Lafferty, Brodeur, Elguero, Gauthier-Clerc & Misse. 2011. Incidence of adult brain cancers is higher in countries where the protozoan parasite Toxoplasma gondii is common. Biology Letters

 

Categories: Medical, Veterinary Tags: , , , , , , , , , , , , , , , , , , ,
25
Jul 2011

Medicine Man

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This past weekend I had an enjoyable experience in Ogdensburg, upstate NY at their annual Founder’s Day commemoration of the region’s French colonial history. They held a re-enactment of the French-Indian War, bringing the mid-18th century to life for a couple of days.

One of the events I attended there was a lecture on “18th Century Medicine”, which was enjoyable, not just because of its fascinating content, but because the lecturer was one of the re-enactors, complete with accompanying props, including an amputation saw…….

Things have certainly changed in medicine over the past few centuries. Back then, only men trained as doctors.

 

Men who trained to be doctors would typically use one of two routes:

  • 7 year apprenticeship
  • 4 years university training combined with a 4 year apprenticeship

 

And these doctors came in one of 3 flavors:

  • Apothecaries would typically be responsible for selling medicines, as well as importing other sundries, such as cosmetics, metallics, and even coffee – basically anything that could be sold in a pretty, little jar! They were the professionals who would take advice from the physician or surgeon as to what the patient needed.
  • Surgeons could be found on the battlefield, on naval vessels, or in shops in town. Most surgeries at that time typically dealt with the limbs, predominantly by way of amputation – although others involved simple sutures, bullet extractions, removal of kidney stones, ophthalmology, dentistry, and rarely, caesarian section if called upon by midwives. Amputation around that time had a success rate of 25-40%, and infection represented the primary cause of death following this or any other surgery – especially so because antibiotics were not yet available, so there was no means of preventing infection in patients.  So if you happened to be the first surgical patient of the day, you definitely had a better chance of survival than the 25th patient of the day who was being operated on with the same instruments that probably hadn’t been cleaned since being first used that morning. Anesthetics also had not yet been developed, but at this time, surgical patients would be given a combination of opium and some kind of alcohol (usually rum, brandy, or wine).
  • Physicians would listen to a patient’s symptoms – they were the observers. So, as professionals, they represented the group that did the least, procedure-wise. Typically they’d be sending patients to either the apothecary or surgeon, based on their symptoms.

 

 

Women’s Work:

The role of women in the medical profession seemed to be mostly limited to midwifery and nursing. Although some complications of childbirth might be dealt with by a surgeon or physician, midwifery was typically the job of women.

Interestingly, nursing in the 18th century was considered the “lowest of the low” professions. Nurses tended to be prostitutes or criminals, and instead of healing their patients, they’d usually be found stealing their money, or providing “special comforts” to gentlemen patients…….a far cry from the pivotal role of nurses in medicine today!

 

So yes, thankfully medicine has changed dramatically over the centuries!

 

 

Categories: Medical, Military Tags: , , , , , , , , , , , ,
04
Jul 2011

Minutemen, Militia and Medicine

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Hippocrates, the Father of Medicine, once said: “If you want to study medicine, go to war”.

In 1776 there were only 3,500 physicians in the colonies. These men clearly played a disproportionate role during the Revolutionary War, with around 1,300 of them serving as military surgeons at this time.

During the war, anyone with medical knowledge of any kind was drafted into service, and although all regiments had their own physicians, less than 300 of them actually had a medical degree. The minority had been trained in Philadelphia, at The Pennsylvania Hospital – the first medical school in the Americas, which opened in 1768. Since there were no laws or professional organizations to regulate medicine, however, this left anyone free to practice.

Inevitably therefore, more soldiers died due to health issues than combat during the Revolutionary War.

Anesthesia was not discovered until the mid 1800s, so alcohol and opium were typical agents used for surgical preparation of patients.  Medical equipment and drugs were in very short supply during the war, and physicians were frequently forced to work with what little equipment they had in their pocket kit. Additionally, they typically performed the only surgery that they knew to be useful – amputation. Surgeons had to work fast, since their patients were not anesthetized, and some reports describe things being stuffed into soldiers’ ears so they could not hear themselves screaming! And there was always the method of “biting the bullet”.

Wounded soldiers awaiting surgery were also first bled. Bloodletting was used to treat just about every type of medical illness, based on ancient beliefs that withdrawing large quantities of blood would purge the sick patient of “bad humors”. To add insult to injury, postsurgical procedures also often involved even more bloodletting! Unsurprisingly, surgical success rates were low at this time, with wartime surgeons having no idea that such blood loss could lead to death.

Overall though, despite the fact that professionally trained physicians were rare in the colonial military organization, Revolutionary Wartime surgeons did extremely well at treating the sick, and attempting to save lives. And although no major medical or surgical advances came from the war, one step forward did come in the form of smallpox control.

Smallpox was not a problem in America until introduced here by European settlers. The American Revolutionary War brought about numerous smallpox outbreaks. Patients who actually survive the disease develop lifelong immunity to it, so the British were at a distinct advantage since many of them had previously suffered the disease.

At that time, there were only two ways to deal with smallpox:

  • Isolation: Where susceptible soldiers were quarantined away from potentially diseased people.
  • Inoculation: Where material from smallpox lesions was extracted and injected under the skin of unexposed individuals.

By 1777, the ever increasing smallpox epidemics had led George Washington to order mandatory inoculation of all troops who had not had the disease. Medical historians actually credit this decision as a pivotal one – smallpox threatened to kill more soldiers than the British would, so it was this decision by Washington that allowed the Continental Army to turn the situation around and continue to fight at full strength.

Thankfully huge advances have been made in medicine since the era of the American Revolution. But one thing that remains unchanged is the fact that physicians continue to serve in the US military, helping not only fellow servicemembers, but foreign citizens too. “Service beyond self” clearly remains the mission of both the caring physician and proud military servicemember.

Happy July 4th everyone!

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