Buzzing around the auditorium before his presentation, Dr. Paul Linser amicably conversed with Hamilton students and professors about the weather, his visit to the Hill, and his perfectly waxed handlebar moustache. His lecture, which was part of the Levitt Series, took place on Feb. 27 in the Taylor Science Center.
The upstate winter felt especially frigid for the distinguished professor of anatomy and cell biology, who came from his lab at the University of Florida in St. Augustine. Yet, he isn’t the only organism opposed to these colder climes; in fact, the specimens he studies, mosquitoes, also prefer the tropics.
As inhabitants of North America, our population is relatively unaffected by the blood borne parasite, malaria, which is typically transmitted by mosquito bite.
While mosquitoes certainly exist in North America, thanks to federal efforts during the 1950’s, malaria has been practically eradicated in the US. The pesticide DDT temporarily devastated the mosquito population, effectively slowing the spread of disease. This allowed sick patients to be treated, dramatically decreasing malaria rates in the country.
Still, worldwide malaria is the most deadly disease transmitted by vector, which is an organism that carries and transmits an infectious pathogen into another living organism. Mosquitoes are very effective vectors, documented carrying more than 600 viruses and four strains of malaria. Plasmodium, parasitic protozoa responsible for malaria, can be traced back 10 to 15,000 years ago, coinciding with the human expansion out of Africa. Although it has been around for thousands of years, malaria was not well understood until the 19th century when Alphonse Laveran discovered the blood borne nature of the parasite and Ronald Ross identified mosquitoes as the vector.
While various methods for decreasing malaria rates exist, due to short-lived mosquito generations and large numbers of offspring, populations evolve rapidly and effectively build resistance to pesticides. To combat this, several new malaria prevention methods have been created. Specifically, Linser points out that bed nets and window screens are particularly effective, especially when combined with a chemical process known as residual spraying.
Another tested process is to create a species of genetically modified male mosquitoes that can be extensively bred and then released into the wild to mate. The impregnated females then give birth to sickly larva that do not mature to adulthood. This method has been proven effective during trials on some islands, but has unknown long-term effects. Additionally, because this method introduces genetically modified organisms into the wild, it has been met with considerable resistance.
The past decade has seen leaps and bounds of scientific achievement, decreasing mortality rates from several million to hundreds of thousands. Yet despite continuing to make progress on this complex and longstanding issue, the global threat could be on the rise. The recent trend of climate change is expected to increase the range of malaria worldwide, putting unprepared populations at risk. While no cure is available yet, thanks to the work by Linser and his colleagues, we’re getting closer to malaria being a word of the past.