Scientists in China say that they've identified two strains of the coronavirus that has nearly 100,000 confirmed infections and has killed more than 3,300 people worldwide, according to preliminary research

Those researchers, from Peking University's School of Life Sciences and the Institut Pasteur of Shanghai, report that 70 percent of the 103 samples they tested had been infected by a more aggressive strain of the virus (the "L" type), while the remaining 30 percent have been tainted by a less aggressive form (the "S" type). According to Reuters, the L-type was found more often in the epicenter of the virus outbreak, Wuhan, China, but the frequency of it has tapered off since January 2020. This could be a result of the serious measures taken by China to try to prevent the virus's spread.

Those who have been studying this say the spike in COVID-19 cases could probably be chalked up to “mutations and natural selection besides recombination.” RNA viruses, of which COVID-19 qualifies, often mutate when they replicate quickly.

As of Wednesday the United States has had more than 160 confirmed cases, and 11 deaths.

Scientists further stated that the data they have is very limited, and that further follow-up research is necessary to better comprehend the disease's evolution. "These findings strongly support an urgent need for further immediate, comprehensive studies that combine genomic data, epidemiological data, and chart records of the clinical symptoms of patients with coronavirus disease 2019 (COVID-19)," researchers said in a study that was published earlier this week.

Also earlier this week, a top medical association in China stated the the maximum incubation period for the disease is 14 days, with the median being between five-to-seven days. Similar information was already out there, but these remarks are the most conclusive ones to come from a government-affiliated medical organization.