No cases have been identified since then, but the source of the outbreak remains uncertain. In 2000, 291 cases of waterborne viral hepatitis A were reported in Uvurkhangai Aimag. Compared with 2015, an decrease in congenital syphilis cases was observed in 2016. Indeed, 42 cases of congenital syphilis were registered in 2016 (52 cases in 2015), 25 of which were registered in Ulaanbaatar. This decrease in congenital syphilis cases was attributed to improved pregnancy monitoring.