Prevalence and effect of Schistosome and soil-transmitted helminth infection on labour input in rice-growing communities of Ogun State, Nigeria

Schistosomiasis and soil-transmitted helminthiasis (STH) are public health problems in communities which lack basic social amenities with poor hygienic conditions. Studies were carried out to determine the prevalence and effect of schistosomes and soil-transmitted helminths infection on labour input on rice production in 9 rice-growing communities of Ogun State. Parasitological examinations of urine and faecal samples, and structured questionnaires were conducted on 243 consented individuals from May 2009 to March 2010. The results showed an overall prevalence of 17% for Ascaris lumbricoides, 12% for hookworms, 2% for Trichuris trichiura, 1% for Schistosoma haematobium and 1% for Schistosoma mansoni. A. lumbricoides and hookworms were more prevalent in Agbajege (25%), and varied in the other 8 communities. T. trichiura was prevalent in three communities, Agbajege (5%), Akodu (4.2%), and Moloko-Asipa (4.8 %); S. haematobium was prevalent only in Ayedere (2.6%) and Lufoko (8%), while S. mansoni was prevalent only in Moloko-Asipa (9.5%). Infections among the gender were varied as 26.3 % of males and 33.8 % of females had an overall prevalence of: A. lumbricoides (16.8%), hookworms (11.8%), T. trichiura (1.6%), S. haematobium (1.1%) and S. mansoni (1.1%). On frequency of infection to incapacitation per year, 45% of respondents were incapacitated 1-2 times, 27% 3-4 times and 19% were incapacitated more than 4 times. Understanding the effect of these two diseases will not only improve the health status of residents but also increase their productivity and ensure food security.


INTRODUCTION
The prevalence of human helminth infections had been reported in many rural communities of the developing world with emphasis on soil-transmitted helminthiasis (STH) and schistosomiasis [1,2,3]  billion, of which ascariasis account for about 1.6 billion while trichuriasis and hookworm amount to about 700-800 million, schistosomiasis which is considered the second most important waterbased parasitic infection after malaria in terms of public health and economic impact affects 200 million people with over 600 million at risk of the disease [2,4].In Sub-Saharan Africa (SSA) they are recognized as important public health problems due to their immense contribution in undermining the health status of the people and jeopardizing economic development in the region [5,6] and because transmission is soil and water-related, their epidemiology had been known to be affected by ecological changes caused by projects for the development of water resources and agriculture [7,8].There is therefore a growing discrepancy between Sub-Saharan Africa and the rest of the world in terms of disease burden resulting from lack of adequate control efforts [2,9].
While infections had been associated with lack of sanitary facilities and farming [5,19,20,21], they rarely cause death, and the burden of disease related to the chronic and insidious effects on host's health and nutritional status is most commonly associated with infections of heavy intensity, however, the effects of untreated helminth infections of any intensity are often difficult to measure and associating them with any particular parasite is even more challenging [3,22,23] .
In recent years a lot of resources and emphasis are being directed toward water resources development to boost agricultural productivity with little or no Health Impact Assessment (HIA) on the effect of STH and schistosomiasis as a result of the various agriculture-oriented environmental modifications on the farming communities [7,24].The increasing importance of rice in food and nutritional security, income generation, poverty alleviation and socioeconomic growth of Africa, especially for a major rice consumer and importer like Nigeria [25] has made it necessary to investigate the effects of STH and schistosomiasis on the rice-growing communities.Thus, the present study was carried out in nine (9) rice-growing communities of Ogun State, South-western Nigeria to describe the prevalence and effects of helminthiasis among the communities.

Study Area
The study was carried out in nine ricegrowing rural communities in two Local Government Areas (LGA) of Ogun State, Nigeria (Figure 1).The communities, as shown in Figure 2, are Asipa Ilao, Abule Alaja, Ayedere, Kere in Ewekoro LGA; and Lukofo, Aiwere, Akodu, Agbajege and Moloko Asipa in Obafemi-Owode LGA.The communities had no access to conventional sanitary facilities, pipe borne water and electricity.The communities were selected based on their importance in local rice production as identified by the Rice Farmers' Association of Nigeria, Ogun State Chapter.

Consent
Consent and approval were obtained from each of the Local Government Area headquarters, the villages Heads or "Baales" of the communities, who also called community meetings where the purpose and procedure of the study was lucidly explained to the community members.

Examination of faecal samples
Properly labeled plastic containers with tight lids into which fresh specimen would be put on the morning appointed for the collection and examination of the faecal samples were provided for each participant.The specimens were collected for helminth examination using the Kato-Katz method.The egg per gram (epg) of faeces was calculated by multiplying the number of eggs in a 20 mg smear by 50.Determination of corrected epg of faeces was adjusted for dilution using stool consistency and multiplied by the correction factors according to [26].Eggs and ova of parasites were observed under x40 magnification of the binocular microscope.The limitation of this was that eggs of hookworm species observed were not distinguishable between the two types of hookworm (Ancylostoma duodenale and Necator americanus).

Screening of urine sample for schistosomiasis
Urine samples were collected in properly labeled conventional 50 ml sample bottles put in black cellophane bags between 9:00 am and 12:00 noon from the participants.10 ml of urine left in the bottles were kept in a dark cupboard for a minimum of 2 hours after which the supernatant was poured out and the sediment transferred on a slide, covered with a cover slip and examined under the light microscope using the x10 objective lens with the condenser sufficiently closed to give good contrast.The numbers of eggs of S. haematobium found on the preparation were reported as number of eggs per 10 ml of urine to indicate intensity of infection.

Knowledge Attitude and Practice (KAP)
The Knowledge, Attitude and Practice (KAP) of community members about illnesses, their causes and effects as well as the general sanitary behaviour in the communities were evaluated through structured questionnaires administered by the researchers to all participants, in addition to personal communication with prominent members of the community.The information sourced included the incapacitation associated with helminthiasis, frequency of incapacitation and the effect on their productivity.Illness is that state of not feeling well in the body, while incapacitation is termed the period or number of days that community members stayed at home and were unable to carry out farming activities.

Data analysis
Data gathered from the questionnaires were analyzed using Epi Info Software version 6.04, and laboratory investigations were entered in Microsoft Excel application and analyzed to obtain the frequencies, analysis of variance, interaction between and within parameters, in addition to test for significance using the Statistical Package for Social Science (SPSS) version 17.0 for windows.

Study population
The age and sex profile of the study population are presented in Table 1.The age distribution which is from age 2 years to over 40 years indicated that majority of the respondent are over 40 years with a frequency of 57% representing 138 members of the 243 member population.Across the study communities, males were 41%, while females were 59%.
On the frequency of incapacitation associated with the diseases yearly by the study population, 45% of respondents reported that they were sick once or twice a year, 27% were sick three to four times a year, 19% were sick more than four times a year while 9.7% reported that they do not fall sick (Figure 3).As a result of their incapacitation, 78.4% (Figure 4), reported that they were unable to work on the farm during the sickness and 21.6% reported that their illnesses did not prevent them from going to work on the farm.

DISCUSSION
This study has attempted to describe the prevalence and effects of schistosomiasis and STH in rice-growing communities of Ogun State.Infection by A. lumbricoides remains the most prevalent followed by the hookworms and T. trichiura in consonance with the findings of [10][11][12][13][14] with highest point prevalence of 25% for both A. lumbricoides and hookworms infection and 5% for trichuriasis, there is however, a generally low prevalence of helminthiasis in the study area and more so for schistosomiasis in line with the findings of [15] in rice growing communities of West Africa.The reason for which may be that the rice ecology practice in the study area which is rain-fed and not flooded, limited the transmission of schistosomiasis.This also lends support to the findings of [7] and [8] that epidemiology of STH and schistosomiasis is affected by ecological modifications due to agriculture.
The effect of the burden of disease which could neither be directly evaluated nor associated with specific helminth infections in the study area as already confirmed by [22] and [23] is however indicative in the different frequencies of incapacitation reported per year by 90% of the study population and the consequent inability of about 78% of the population to do any farm work during these incapacitation.This finding reveals how helminthiasis could undermines people's health and jeopardizes economic growth as recognized by [5] and [6].
In conclusion, the present study has given insight on the prevalence and possible effects of helminthiasis on peoples' productivity in some rice-growing communities of Ogun State Nigeria.Though, the prevalence of helminthiasis is low which may not be unconnected to the relatively small sample population of the participants.This is however, the major limitation of the present study.Nevertheless, the prevalence could as a matter of time increase considerably if an effective anti-helminthiasis strategy is not instituted when considering the lack of social amenities and pipe borne water which could prevent indiscriminate refuse dumping and frequent visit to contaminated rivers.
The increase in prevalence would further render larger population unproductive and aggravate their health burdens.The conditions will axiomatically hamper socio-economic development and food security.There is therefore a need for integrated disease interventions aiming at reducing the helminthiasis burden and increasing the productivity of the residents at the study area.Such interventions should include, among others, the treatment of the communities with paraziquantel and antihelminthic drugs, periodic public health education on cleanliness, hand-washing and provision of basic social amenities such as pipe borne water, motorized borehole and public toilets.These measures will undoubtedly reduce the risks and burden of schistosomiasis and helminthiasis and improve the well-being and productivity of these farming communities.

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and global estimates of infections had been put at over 2 Epidemiology Biostatistics and Public Health -2013, Volume 10, Number 2 SCHISTOSO mE AN d SOIL -TRANS mITTE d HELmINTH INf ECTION IN NIGERIA figure 1The 2 LgAs (inseT mAp) of ogun sTATe Public Health -2013, Volume 10, Number 2 SCHISTOSO mE AN d SOIL -TRANS mITTE d HELmINTH INf ECTION IN NIGERIA

figure 3 frequencyFrequency
figure 3 frequency of incApAciTATion experienced per yeAr Among respondenTs in The sTudy AreAs

Frequency
figure 4 aCknowledgements: the authors appreciate the support and cooperation of the community heads and members, the local government officials and the officials of the Ogun State rice farmers association towards the study.

TAbLe 1 Age
And sex disTribuTion of respondenTs in The sTudy AreA

TAbLe 3
prevALence of heLminTh pArAsiTes in sTudy communiTies of ewekoro LgA