Student Presenter(s): Nayan Pallothu
Faculty Mentor: Leonidas Salichos
School/College: Health Professions, Old Westbury

Hepatitis D virus (HDV) is responsible for 48 million infections worldwide. Transmission of HDV can occur either through coinfection or superinfection with hepatitis B (HBV). In combination with HBV, hepatitis D has the highest fatality rate of all hepatitis infections, at 20%. HDV has a wide geographic prevalence in many countries in Western and Central Africa, however, the history of genotype 1 is mostly unknown. Using a Bayesian coalescent skyline analysis, two noticeable upticks in population growth are noticed, around the early 1700s and a more significant increase in population in the early 1900s. The analysis also revealed most patient sequences clustered with Genotype 1 and it is possible to infer that they can be further divided into 2-3 major clades. These clades show a common ancestor between 1935 and 1955 suggesting the introduction of HDV to the region the patient data was sourced from was around this time. The Birth and Death model displayed a mutation rate of 3.04E-4 with a 95% HPD interval of 3.45E-5 to 5.72E-4. Through the Birth Death Skyline Serial Analysis, the Reproductive number (Re) was estimated for 5 distinct periods. The estimated Re per period were 1.4, 1.5, 1.4, 1.4, and 4.15 respectively. After the virus was introduced in Italy, our data shows that there has been a significant increase in its reproduction number, suggesting that every person is now responsible for a little more than 4 infections.