Why diseases matter

I was 25 when I got very, very sick. After six weeks of illness, four doctors who had no idea what was wrong, and two weeks in hospital, I was finally treated for giardia diarrhea I had caught in the countryside two months earlier. It took months to feel back to my old self, and I had post-traumatic stress symptoms for years.

Once I got back to something like everyday life, I began to notice that our society’s views of illness did not match the reality in many ways. As I started to work at the Canadian Medical Association Journal and learned much more about illness, this view was reinforced.

The reality is that most illness – in Canada and certainly elsewhere – is a matter of bad luck. You are in the wrong place at the wrong time and you catch something. Or something in your body misfires. Or a remote relative had a bad gene.

On a public-health level, society can make changes to prevent disease: vaccinations, good sanitation and water treatment, advisories to wash your hands, and surveillance and screening programs. But at the moment that those systems break down and a person gets a disease, there’s really not much that can be done.

At the same time, health classes in schools do not teach much about disease causation or medical care. Many Canadians come from cultures (and I’m talking about my own here) that see illness as a failing, either of morals or self-care or stoicism. Others see illness as someone’s – either the patient’s or the doctor’s — “fault.” Still others see illness in superstitious terms, even in this day and age. Many Canadians still think little of medical science and still say “I’ve never taken a day off work sick.” Well, either they were very lucky or they were going to work with viruses and infecting their colleagues.

Sometimes I prefer the views of those from other countries where diseases are more prevalent and acknowledged as a fundamental part of human existence. I believe from my own experience and my work that disease, disability and death are part of what makes us human.

Back in Canada, there’s an inaccurate view among people who have not had serious diseases that they happen only to people with poor lifestyles or people in other countries. That is manifestly not true. If you think about it, either you or your friends and family members have been profoundly affected by diseases: heart disease, cancer, rheumatoid arthritis, multiple sclerosis, ALS, SLE, diabetes, etc., etc.

There are a lot of things said in the street, in the media and even in medical literature about what causes these diseases, but biomedical researchers working on them are much more circumspect. In many cases, we do not really understand how these diseases start, or the things we have been saying are turning out to be incomplete — or even completely incorrect.

My feeling is that we are at the beginning of a coming explosion of knowledge on diseases, which will transform prevention and treatment. Because how can you prevent or treat a disease until you understand what is causing it?

Citizen science and the loss of the loon

The sight of a painting-perfect loon on a lake this weekend reminded me that I covered the annual loon count on this blog three years ago. In that post, I discussed how Bird Studies Canada had turned the national summer pastime of watching loons into an exercise in “citizen science” — the involvement of non-scientists in scientific endeavours.

Now the Canadian Lakes Loon Survey has yielded important scientific evidence.

The common loon, with its characteristic silhouette and unearthly like-no-other-animal calls, stands out in another way. It is an “indicator” or “sentinel” species, defined as an organism that is sensitive to the environment and hence can provide an indication of the health of that environment. A canary in a coal mine, a distant-early-warning system.

In a study published this year in Avian Conservation and Ecology, authors Tozer, Falconer and Badzinski used the data from citizen observations to model the reproductive success of common loons in Canada. Loons are sensitive to changes in pH (acidity) and to methylmercury, making them an important indicator species for changes in these variables. Furthermore, methylmercury in combination with higher temperatures and acidity has a synergistic effect — more than the sum of its separate effects — on loon breeding success.

The analysis shows that loon reproduction has been going down at a worrying rate since 1992. Reproduction is more successful in western Canada than eastern. These findings are correlated with changes in acidification of lakes and methylmercury levels, but the authors caution that there may be unknown factors in addition. A correlation like this one is suggestive, but cannot prove cause-and-effect.

According to the model these authors developed, at a certain pH level in a lake, loons no longer reproduce enough to replace themselves. That is, the population no longer increases but starts to decline. In biology, this is called the “source-sink” threshold.

In lakes with a pH of 6.0, this threshold may have already been breached in 2001, according to the calculations. Other lakes with a current pH of 8.0 probably won’t hit this point until about 2034. Overall, the authors figure that the population is still increasing, but marginally, and if the declining trend continues, the total population will soon start to decline.

This is a different picture from the one painted by another study, the breeding bird survey, which showed increasing numbers over the same period. By contrast, while this new study indicates overall increase, it shows lower success rates, decelerating into the negative zone in some areas.

It’s an impressive achievement for citizen science, which has proven its worth, providing more data than possible in a limited scientific survey.

It’s also a red flag on environmental mercury and continuing acid rain. These problems have not gone away — far from it. The loon’s call is a warning not only about one of our iconic fauna but also about the future of our delicate lake ecosystems.