MONRATE, a descriptive tool for calculation and prediction of re-infection of Ascaris lumbricoides

Abstract

The objective of the study was to develop an interactive and systematic descriptive tool, MONRATE for
calculating and predicting reinfection rates and time of Ascaris lumbricoides following mass chemotherapy using
levamisole. Each pupil previously treated was retreated 6 or 7 months after the initial treatment in Ogun State, Nigeria.
The implementation was based on the theoretical equation for time-prevalence: Y = G [1 -(1-X)N-R]. Using the Psuedo-
Code of the MONRATE tool, the calculated monthly reinfection rates (X) for the LGAs were 1.6% in Ewekoro, 2.3% in
Odeda, 2.3% in Ado-odo/Otta, 3.8% in Ogun Waterside and 4.2% in Obafemi/Owode. The mathematical mean of 'X'
values in the study areas for Ogun State was 2.84. The calculated reinfection time (N months) for the LGAs varied such
as Ado-odo/Otta (12.7), Ogun Waterside (21.8), Obafemi/Owode (22.92), Odeda (25.45), and Ewekoro (25.9). The mean
value for N in Ogun State was 21.75. The results obtained from MONRATE were compared with those obtained using the
mathematical equation and were found to be the same but MONRATE was faster in computation and more accurate. It
is concluded that MONRATE is a veritable tool that can be used in the execution of control programme involving mass
treatment against A. lumbricoides.

Keywords: MONRATE, Ascaris lumbricoides, re-infection rate, Nigeria

Tanzania Health Research Bulletin Vol. 8 (2) 2006: pp. 75-79