Sex and age distribution of study participants
A total of 1,499 respondents were subsequently enrolled after consent across the 33 communities and 20 LGAs. However, only 1,027 (68.5%) of them consented to the provision of adequate stool samples ( g) for laboratory analysis for parasites’ ova or larva. By demography, 899(60.0%) were females and 600(40.0%) were males. The sex ratio of females to males was 3:2. In addition, the highest number of respondents were within the age range 41-70yrs (40.6%), followed by 26-40yrs (30.3%), 5-15yrs (10.7%), 16-25yrs (10.4%) and >70yrs (7.0%) (Table 2).
Spatial distribution of Ascaris, Trichuris and Hookworm infections in Ogun State
Figure 2 shows the spatial distribution of the three parasites’ in Ogun State. Of the 20 LGAs examined, 19(95.0%) were endemic for one or more of the three parasite. Ascaris lumbricoides are the most geographically distributed, found in 28(84.8%) out of the 33 communities and 19(95.0%) out of 20LGAs. Hookworm was present in 19(57.6%) out of 33 communities and 15(75.0%) out of 20LGAs. Trichuris trichiura infections were found in 9(27.3%) out of 33 communities and 7(35.0%) out of 20LGAs.
Co-distribution patterns of Ascaris, Trichuris and Hookworm infections in Ogun State
Figure 3 shows the co-distribution patterns of STH infections in the State. Mono-infection was recorded only for Ascaris lumbricoides in 3 LGAs; Ewekoro, Ikenne and Ijebu northeast. For double infections, co-distribution of Ascaris and Hookworm were the most predominant, observed in 15 LGAs except Ewekoro, Ijebu east, Ijebu northeast, Ikenne and Ijebu ode. Ascaris and Trichuris co-distribution was recorded in 7 LGAs; Yewa north, Yewa south, Ado-odo ota, Ijebu east, Ipokia, Obafemi owode and Ogun waterside, while Trichuris and Hookworm co-distribution was recorded in 6 LGAs; Ado-odo ota, Ipokia, Obafemi owode, Ogun waterside, Yewa north and Yewa south. However, for triple infections, the three species (Ascaris, Trichuris and Hookworm) were co-distributed in 6 LGAs; Ado-Odo, Ipokia, Obafemi-Owode, Ogun waterside, Yewa North and Yewa South (Table 3).
Aggregated prevalence of Ascaris, Trichuris and Hookworm infections in Ogun State
The aggregated prevalence of 17.2% was recorded for at least one infection of Ascaris lumbricoides, Trichuris trichiura or hookworm. The prevalence range was between 5.3 – 49.2% across the LGAs (Figure 4). Infections were highest in Yewa south, lowest in Yewa north and no infection was recorded in Ijebu-Ode. Of the 19 endemic LGAs, 9 had prevalence status ranging between 20.0%-49.2% (Abeokuta north, Abeokuta south, Ifo, Ikenne, Ipokia, Obafemi owode, Ogun waterside, Remo north and Yewa south). However, 10 LGAs had prevalence status ranging between 5.3%-15.8% which is below the WHO recommended thresholds for preventive chemotherapy (Ado-odo ota, Ewekoro, Ijebu east, Ijebu north, Ijebu north east, Imeko afon, Odeda, Odogbolu, Sagamu and Yewa north). There were significant differences in the prevalence record for any STH species across the 19 endemic LGAs (P=0.000) (Figure 5).
Specific prevalence estimates for Ascaris, Trichuris and Hookworm infections in Ogun State.
By species prevalence, Ascaris lumbricoides infection was the most occurring 140(13.6%), followed by Hookworm 47(4.6%) and Trichuris trichiura 17(1.7%) (Table 3). For Ascaris lumbricoides infections, a total of 140 participants were positive with an overall prevalence of 13.6%. The prevalence for Ascaris lumbricoides ranges between 2.6% and 37.5%, with the lowest prevalence observed in Yewa north and highest in Abeokuta south (Table 3). Spatially, Ascaris lumbricoides are the most predominant, found in 28(84.8%) out of the 33 communities surveyed (Figure 6). An overall prevalence of 4.6% was also recorded for hookworm infections across the 19 LGAs, with a range between 1.8% and 16.7%, the lowest prevalence was observed in Yewa north and the highest in Obafemi owode LGA (Table 3). No hookworm infection was recorded in 5 of the 20 LGAs i.e. Ewekoro, Ijebu east, Ijebu north east, Ikenne and Ijebu ode. Spatially, Hookworm was the second most occurring infection following Ascaris and it was observed in 19 (57.6%) of 33 communities surveyed (Figure 7). There were significant differences in the prevalence record for Hookworm infections across the endemic 15LGAs (P=0.000). For Trichuris trichiura, an overall prevalence of 1.7% was recorded across the 19 LGAs, with a range between 0.9 % and 23.1 %, the lowest prevalence was observed in Yewa north and the highest in Ipokia (Table 3). Only 7 out of the 20 LGAs were positive for Trichuris trichiura infections i.e. Ado-Odo Ota, Ijebu-East, Ipokia, Obafemi-Owode, Ogun waterside, Yewa North and Yewa South. Trichuris trichiura infections was found in 9(27.3%) out of 33 communities surveyed (Figure 8). There were significant differences in the prevalence record for Trichuris trichiura infections across the endemic 7 LGAs (P=0.000).
Aggregated and specific mean intensity estimates for Ascaris, Trichuris and Hookworm infections in Ogun State.
Table 4 shows the intensity estimates for Ascaris, Trichuris and hookworm infections in Ogun state. The aggregated geometric mean intensity of infections was 0.14 0.01 with mean intensity ranging from 0.03 0.01 to 0.43 0.06 across the LGAs. The aggregated intensity shows that worm loads were highest in Obafemi owode and lowest in Imeko-afon. By species intensities, Ascaris lumbricoides infection intensities was the highest 0.11 0.01, followed by Hookworm 0.03 0.01 and Trichuris trichiura 0.01 0.00. Ascaris mean intensities range between 0.01 0.01 and 0.32 0.05, with the lowest in Imeko afon and highest in Ifo and Yewa south. For Hookworm infection, intensities range between 0.01 0.00 and 0.13 0.04, with the lowest in Ijebu north, Yewa north, Yewa south, Ogun waterside, Imeko afon and highest in Obafemi-owode. Trichuris mean intensities range between 0.01 0.01 and 0.10 0.05 with the highest load in Ipokia and the lowest in Ogun waterside, Ijebu east and Yewa north.
Prevalence of Ascaris, Trichuris and Hookworm infections infection by sex and age characteristics
Table 5 shows the prevalence of infection by sex and age distribution of study participants. Majority of those infected were females 122(18.8%), although there were no significant differences in prevalence estimates across sex (P > 0.05). By age category, majority of those infected were adults and with age above 26 years, however there were no significant differences in prevalence of infection across age category (P > 0.05).