Malaria, a sometimes deadly parasite spread by mosquitoes, represents a very serious health and economic threat to people who live close to the equator. It is especially prevalent in Africa. It's one of the oldest maladies that afflict us. Malaria has been with us for literally the entirety of recorded history - accounts of it can be found as early as 2700 BC, in ancient China. In fact, even our genetic forebears suffered from a prehistoric strain of Malaria.
Stephanie Marciniak, a biological anthropologist working out of Pennsylvania State University, led a research effort to investigate the incidence of Malaria in the Roman empire. She and her team studied teeth of 68 Romans who died during the Imperial period, which spanned from the first to the third centuries A.D. The skeletons - 58 adults and 10 children - were taken from three cemeteries that were likely designated for laborers.
Ancient writers described Malarial symptoms occurring during the period, but it was unknown which parasite constituted the major transmission vector. Malaira is caused by parasitic single-celled organisms called Plasmodia. There are five distinct species of Plasmodium parasite that cause Malaria in humans. Some are deadlier than others.
Unfortunately, getting a positive ID on Plasmodium species requires DNA analysis. Which presents a steep challenge when dealing with antique samples, since Plasmodia mostly accumulate in soft tissues like internal organs and blood. Marciniak hoped that she would be able to cultivate enough Malarial DNA from the Roman teeth to identify which specific species of Malaria afflicted Rome.
Scientists Against Malaria
It was almost a bust. Thankfully, there was enough DNA in two of the fifty-eight sets of teeth to make a judgement. The researchers were able to isolate the DNA signature of the Plasmodium falciparum parasite. The findings are interesting, but it is difficult to infer much about the disease's epidemiology from them.
"Finding Plasmodium falciparum malaria in the two adult skeletons cannot be extrapolated to interpretations about widespread death or catastrophe caused by this parasite in Imperial-period Italy," said Marciniak.
The research does reveal that Malaria afflicted both coastal and inland regions. Malaria did cause mass fatalities during the period, but it is unclear whether the two people from which the DNA was extracted were actually killed by the disease.
Plasmodium falciparum is the most dangerous strain of Malarial parasite, and is responsible for the most contemporary human deaths associated with the disease. It is carried by female Anopheles mosquitoes and kills about 50% of the people it infects. Unfortunately, the fatality rate is especially high in children. P. falciparum is especially prolific in sub-Saharan Africa, where it accounts for about 75% of all human infections. P. falciparum is responsible for the vast majority of malarial deaths and kills more children than any other infectious disease.
Scientists are continuing to collect data about the shape and scope of Malarial infections in the ancient world, in the hope that it will give them insights into the parasite's evolution.