Markovian Modeling the changes in Prevalence of Soil-Transmitted Helminths in response to praziquantel treatment in Mwea

Abstract

Approximating the reduction level of STH infections is important in policy and decision making nationally as well as globally.This is to ensure the control measures put in place aligns withWHOrecommendation of infections control and intervention.There have been various statistical models that have been utilised in studying infectious disease pattern toward arriving in informed decisions regarding mitigation and interventionn measures.in containing the spread of STH infections. However, majority of models have not given e cient guidelines for predicting the future course of epidemic.Unlike the previous study which experienced limitation due to lack of data of at least 200 individuals,this study aimed to apply the Markov model with baseline data of at least 1500 individual who tested positive of infections. This pre-post study was used the parasitological data collected during a deworming programme for school going children aged 1-15 years conducted in Mwea between 2004 and 2007 to calculate the prediction by calculating the transition probabilities of di erent states of intensity following the rst year of annual MDA administration and subsequent three years with treatment done once per year. The initial study done in 2004 involved a baseline parasitological survey on STH and schistosomiasis conducted in a total of 91 schools in Mwea.41 schools were selected as follow up sample at multiple points each year for four years and examined for intestinal helminths.The sample total was 3809 children who were then treated annually with albendazole (400mg) and praziquantel with the number assumed to remain the same. Treatment coverage between the years 2004 and 2009 was reported at approximately 40,000 school going children in Mwea . During the years 2012-2013, treatment coverage for Mwea was 48,602, while in 2013-2014, the coverage was at 46,999 . The annual treatment of the school going children has continued in all the schools in the area over the years, except for year 2010 and 2011 when the program stopped temporally. Results:At baseline, the prevalence of any STH was 44.3% . Hookworm was at 12.1%, Ascaris lumbricoides was at 2.2%, and Trichuris trichiura was at 1.4%. The male prevalence was highest with 23.7% while that of women was at 20.6% at baseline. After treatment, prevalence of STH decreased to 11.5%, (T. trichiura 0.3%,A. lumbricoides 0.6%, and hookworm 1.2%). In conclusion,we recommend the Markov chain model technique as viable for modeling the transitional changes estimates of infections outcomes at discrete time steps for future predictions.