My brief excursion into the realm of vector-borne diseases
I’ve never had malaria, and I don’t know anyone else who has had it. I’ve never had yellow fever, either, nor do I know anyone who has had that. To be honest, I haven’t ever given much thought to these diseases until recently, when I read a handbook designed for employees at the Mosquito and Vector Control Association of California. Next, I read a book called Mosquito: A Natural History of Our Most Persistent and Deadly Foe.
Now, I’m astounded that we’ve actually maintained control over such diseases for all these years.
OK, a quick natural biology lesson: Mosquitoes have been around since the Jurassic period—which existed 206 million to 144 million years ago—so the ancestors of the mosquitoes biting you today actually feasted on dinosaurs. During those many millions of years, mosquitoes were constantly involved in an evolutionary race with predators that wanted to eat them. They won that race, since they always managed to survive and thrive.
The fact that mosquitoes morph and adjust to different circumstances makes it even more amazing that vector control groups have been able to control diseases spread by mosquitoes.
Since much of the Sacramento area’s natural state is swampland, and since more than 1 million people reside here, our region could be considered a prime place for a malaria epidemic, similar to what Africa has experienced. It’s only because of the tremendous efforts of mosquito and vector control associations that we have been able to effectively control these diseases.
But when you’re dealing with a pest that has been around for 200 million years, there’s always the next round. As the population of the country increases, and as trade between different countries enables easy mosquito hopping from place to place, there will be outbreaks here. That’s especially true because mosquitoes are able to evolve and are good at becoming resistant to diseases and pesticides. After all, a disease spread by a mosquito is up to seven times more infectious than a flu virus.
In certain countries, tremendous advances have been made in treating mosquitoes by spraying the synthetic pesticide DDT on a wall. After a mosquito bites its prey, it becomes so engorged with blood it can’t fly long distances, so it lands on a wall to wait until the blood is digested. If there was DDT on that wall, the mosquito would be killed … until some supermosquito was able to pump its wings a bit farther and land outside on a tree instead of a wall. Wham-o bang-o, we have malaria again!
I truly had my eyes opened by this excursion into the world of vector-borne diseases. Mostly, it was stunning to discover that the 71 people working at the Sacramento-Yolo Mosquito and Vector Control District, in conjunction with other associations and water-treatment agencies, have been so successful at controlling outbreaks in our region. They are unsung heroes for this, as they’ve greatly increased our life expectancy—some would say as much as all the medical professions in the country combined. Thanks to you all for our malaria- (and yellow fever-) free lives!