Abstract:
Soil-Transmitted Helminths (STHs) which affect approximately two billion people globally
is a common public health concern in developing nations. Dynamics of host and
environmental factors results in fluctuations in the parasite infectivity rate. Thus
demographic information in endemic localities is necessary. Therefore, there is need to
constantly update epidemiological data across geographic zones including remote endemic
areas. Hence, this study was designed to evaluate the current knowledge, attitude, and
practices, as well as environmental factors influencing the prevalence and intensity of STHs
in Ibadan.
Soil samples (n=1980) were collected at a depth of 2-3 cm from five sampling sites (toilet
areas, dumpsites, playgrounds, roadsides, and house vicinities) in the 11 Local Government
Areas of Ibadan: South-East, South-West, North-East, North-West, Ibadan North, Akinyele,
Ido, Lagelu, Egbeda, Oluyole and Ona-Ara, from January 2017 to December 2018. Faecal
samples (n=1100) were also collected from consenting participants visiting Primary Health
Centres. Parasite prevalence and intensity in soil and faecal samples were determined using
standard methods, while temperature, rainfall, and Relative Humidity (RH) data were
obtained from the Nigerian Meteorological Agency. Structured questionnaires were also
administered to the consenting participants to obtain information on demographics (age,
sex), and hygiene practices. Data were analysed using descriptive statistics, principal
component analysis, and ANOVA at α0.05.
Soil contamination with at least one STH was recorded in 54.9% of samples examined. Soil
parasite prevalence (%) were 39.9 (hookworm larvae), 26.8% (Strongyloides larvae), 19.9%
(Strongyloides adult), and 13.4% (Ascaris). Prevalence (%) by location was 49.2 (SouthEast), 48.1 (South-West), 48.3 (North-East), 49.8 (North-West), 47.4 (Ibadan North), 51.1
(Akinyele), 52.2 (Ido), 55.1 (Lagelu), 53.6 (Egbeda), 51.8 (Oluyole), and 54.3 (Ona-Ara).
Dumpsites had the highest mean parasite intensity (epg) of 216.2±211.5, 120.4±119.6 (toilet
areas), 75.1±73.6 (roadsides), 13.7±11.8 (playgrounds), and 3.4±1.8 (house vicinities).
Faecal samples had overall prevalence of 35.9% with Ascaris being the most frequently
occurring (41.6%), hookworm (24.5%), Trichuris (23.4%), and Strongyloides (10.4%).vi
Highest parasite prevalence (%) in faecal samples was 38 from Ona-Ara, 36 (Lagelu), 35
(Ido), 34 (South-East), 32 (Egbeda), 31 (Akinyele), 30 (North-East), 29 (North-West), 28
(South-West), and 26 (Ibadan North). Overall intensity (epg) of faeces was 1043 (Ascaris),
771 (hookworm), 315 (Trichuris), and 210 (Strongyloides). Parasite prevalence (60.0%)
was highest in November (mean temperature 30.9ºC; rainfall: 39 mm; RH: 83%), while
intensity (359) was highest in March (27.4ºC; 67mm; 86%). Principal components 1, 2 and
3 accounted for 93.1% of total variations with RH (0.9) and rainfall (0.7) influencing STH
prevalence (0.6) and intensity (0.7). Prevalence of infection was significantly higher in male
(64.3%) than female (35.7%) participants. Prevalence was highest (23.4%) in 11-20 years
and lowest (3.4%) in 51-60 years. Participants practicing open defaecation (22.4%) had a
prevalence of 59.9%. However, participants that walk barefooted had STH prevalence of
60.7%.
Inadequate knowledge, open defaecation practices, and walking barefooted coupled with
favourable climatic factors facilitated transmission of soil helminths in Ibadan.
