Mo. Rev. Stat. § 54.150
The county treasurer shall settle his accounts with the commission semiannually, in June and December in each year. In the event of a vacancy caused by death, resignation, or otherwise, in any county except a county with a charter form of government, the county commission shall appoint a deputy treasurer or a qualified person to serve as an interim treasurer until said treasurer returns or the unexpired term is filled under section 105.030. The treasurer or interim treasurer shall immediately make such settlement, and deliver to his successor in office all things pertaining thereto, together with all money belonging to the county; and at each settlement the commission shall immediately proceed to ascertain, by actual examination, the amount of balances and funds in the hands of such treasurer to be accounted for, and to what particular fund or funds it appertains, and cause to be spread on its records, in connection with the entry of such settlement, the result of such examination and count.
§ 54.150, RSMo