Malaria Was Common In The Roman Empire

[R]esearchers have discovered genomic evidence of malaria in 2,000-year-old human remains from the Roman Empire, according to a new study. 

With DNA fragments from the teeth of 58 adults and 10 children buried in three imperial-period Italian cemeteries, researchers were able to recover the mitochondrial genome to identify the specific malaria species that infected people. 

Their data confirm that it was the malaria parasite Plasmodium falciparum, the same one that is spread by mosquitoes today and kills hundreds of thousands of people every year. Symptoms include fever, chills and flu-like illness. 

"Malaria was likely a significant historical pathogen that caused widespread death in ancient Rome," said evolutionary geneticist and study author Hendrik Poinar, director of the Ancient DNA Center at McMaster University in Hamilton, Ontario. 

The researchers estimate that malaria killed as many people during the Roman Empire as it does now in Africa. In 2015, there were an estimated 438,000 malaria deaths worldwide, with 91% of them occurring in sub-Saharan Africa, according to the World Health Organization.

From here.

The headline of the media report above asks if malaria caused the fall of the Roman Empire, which is pretty much definitively a "no" because the samples taken are from three to four centuries before the empire fell.

It is notable that there is only a very thin historical record of this massive public health problem despite the depth of contemporaneous records we have from this area in this time period. The paper and abstract are as follows:

The historical record attests to the devastation malaria exacted on ancient civilizations, particularly the Roman Empire. However, evidence for the presence of malaria during the Imperial period in Italy (1st–5th century CE) is based on indirect sources, such as historical, epigraphic, or skeletal evidence. Although these sources are crucial for revealing the context of this disease, they cannot establish the causative species of Plasmodium. Importantly, definitive evidence for the presence of malaria is now possible through the implementation of ancient DNA technology. As malaria is presumed to have been at its zenith during the Imperial period, we selected first or second molars from 58 adults from three cemeteries from this time: Isola Sacra (associated with Portus Romae, 1st–3rd century CE), Velia (1st–2nd century CE), and Vagnari (1st–4th century CE). We performed hybridization capture using baits designed from the mitochondrial (mtDNA) genomes of Plasmodium spp. on a prioritized subset of 11 adults (informed by metagenomic sequencing). The mtDNA sequences generated provided compelling phylogenetic evidence for the presence of P. falciparum in two individuals. This is the first genomic data directly implicating P. falciparum in Imperial period southern Italy in adults.

Stephanie Marciniak, et al., "Plasmodium falciparum malaria in 1st–2nd century CE southern Italy" 26(23) Current Biology 1220-1222 (December 5, 2016).