schistosomiasis is a parasitic disease caused by blood flukes ( trematodes ) of the genus schistosoma . an estimated 700 million people are at risk for infection , particularly agricultural work and domestic chores , in 76 endemic countries , and transmission is interrupted in some countries . more than 207 million people are infected with schistosomiasis worldwide and approximately ; 85% live in africa . after malaria and intestinal helminthiasis , schistosomiasis is the third most devastating tropical disease in the world . today , 120 million people are symptomatic with schistosomiasis and 20 million having severe clinical disease . more than 200,000 deaths per year are due to schistosomiasis in sub - saharan africa . , the risk of infection is highest among those who live near lakes or rivers . although ethiopia is one of the countries with high burden of schistosomiasis , there is no control program in the country . in addition , there is no up - to - date map of schistosomiasis in the country . the lack of information on the prevalence and distribution of schistosomiasis in somali region is marked in comparison to other parts of the country . therefore , the aim of this study was to describe the distribution and determinants of schistosomiasis in afder and gode zone of somali region , ethiopia . somali region is located in the eastern part of ethiopia 635 km far from addis ababa . the region is divided to 52 districts and nine zones with a total population of 4 , 439 , 147 . recently , all seven wabi shebele river basin districts report cases of schistosomiasis . as a result a community - based cross - sectional study conducted from february 1 to march 28 , 2011 in six ( hargele and cheriti from afder zone and kelafo , mustahil , gode , and adadile from gode zone ) of 15 districts of afder and gode zones . due to security reason during the time of the survey , we excluded one of the river basin districts . forty - two health centers and 55 health posts provide health services in these six districts . one school from each site was randomly identified ; 523 school - aged children ( 5 - 15 years ) were selected using a simple random sampling technique after obtaining the lists of students from school registration books . the sample size was estimated using a single proportion sample size formula by considering the following parameters : s. haematobium prevalence of 68% , 95% confidence level , and 4% margin of error . all urine and stool samples were collected between 10 and 14 h in the field , by a trained laboratory technician . from each subject , 10 ml of urine was collected in a properly labeled , clean , and sterile specimen container . sedimentation techniques were employed to analyze the samples . a total of 10 ml urine was taken from the deposit of each specimen bottle after allowing it to sediment for about an hour . children were given labelled stool containers with tight covers bearing the serial numbers of the subjects and were asked to give approximately 5 g of stool . these slides were examined under the microscope at 10 magnifications . as a quality control measure , we sent all positive samples and 10% of negative samples to the somali regional laboratory core process team , and all the samples reexamined for the presence of schistosomiasis by the regional expert . a multivariate analysis was done to determine the presence of a statistically significant association between explanatory variables and the outcome variables ( presence of schistosomiasis ) . explanatory variables were considered associated with the outcome variable in the bivariate analysis at ( p < 0.05 ) . odds ratios ( ors ) and their 95% confidence intervals ( ci ) were calculated . individual caregivers were asked to consent verbally for their school - aged children to participate in the study . only those who provided consent were registered and requested to provide samples . to document verbal consent , the name of each individual who provided verbal consent was recorded , and their sample test results were subsequently recorded with these names . individuals who tested positive for schistosomiasis infection were treated with praziquantel , according to world health organization guidelines . somali region is located in the eastern part of ethiopia 635 km far from addis ababa . the region is divided to 52 districts and nine zones with a total population of 4 , 439 , 147 . recently , all seven wabi shebele river basin districts report cases of schistosomiasis . as a result a community - based cross - sectional study conducted from february 1 to march 28 , 2011 in six ( hargele and cheriti from afder zone and kelafo , mustahil , gode , and adadile from gode zone ) of 15 districts of afder and gode zones . due to security reason during the time of the survey , we excluded one of the river basin districts . forty - two health centers and 55 health posts provide health services in these six districts . one school from each site was randomly identified ; 523 school - aged children ( 5 - 15 years ) were selected using a simple random sampling technique after obtaining the lists of students from school registration books . the sample size was estimated using a single proportion sample size formula by considering the following parameters : s. haematobium prevalence of 68% , 95% confidence level , and 4% margin of error . all urine and stool samples were collected between 10 and 14 h in the field , by a trained laboratory technician . from each subject , 10 ml of urine was collected in a properly labeled , clean , and sterile specimen container . sedimentation techniques were employed to analyze the samples . a total of 10 ml urine was taken from the deposit of each specimen bottle after allowing it to sediment for about an hour . children were given labelled stool containers with tight covers bearing the serial numbers of the subjects and were asked to give approximately 5 g of stool . these slides were examined under the microscope at 10 magnifications . as a quality control measure , we sent all positive samples and 10% of negative samples to the somali regional laboratory core process team , and all the samples reexamined for the presence of schistosomiasis by the regional expert . a multivariate analysis was done to determine the presence of a statistically significant association between explanatory variables and the outcome variables ( presence of schistosomiasis ) . explanatory variables were considered associated with the outcome variable in the bivariate analysis at ( p < 0.05 ) . odds ratios ( ors ) and their 95% confidence intervals ( ci ) were calculated . individual caregivers were asked to consent verbally for their school - aged children to participate in the study . only those who provided consent were registered and requested to provide samples . to document verbal consent , the name of each individual who provided verbal consent was recorded , and their sample test results were subsequently recorded with these names . individuals who tested positive for schistosomiasis infection were treated with praziquantel , according to world health organization guidelines . out of 513 samples examined , 82 ( 16.0% ) were positive for s. haematobium ( 95% ci ; 12.8 - 19.2 ) . the prevalence rates of the disease were not uniform across the various six communities studied ( x = 208.8 , p < 0.0001 ) . musthail district had the highest prevalence of 61 cases ( 64.2% , 95% ci ; 60.0 - 68.3 ) , followed by kelafo 9 cases ( 11.8% , 95% ci ; 9.0 - 14.6 ) , cheriti 7 cases ( 8.7% , 95% ci ; 6.3 - 11.1 ) and hargele 5 cases ( 6% , 95% ci ; 3.9 - 8.0 ) , while gode and adadile had no infected persons [ table 1 ] . distribution of schistosoma haematobium by age , sex , and communities in afder and gode zone , somali regional state boys had high rate of prevalence with 40 cases ( 20.4% ) than girls with 42 cases ( 13.2% ) ( p < 0.033 ) as shown in table 1 . across age groups , the highest prevalence was recorded in the 14 - 16 year age cohort ( 19.7% ) , followed by the 8 - 10 and 5 - 7 age cohorts ( 18% and 16.1% , respectively ) , but there was no significant differences ( p > 0.05 ) between these age groups . no infections of s. mansoni were found in the six districts of afder and gode zone . the geographical distribution of s. haematobium in the six districts is presented in figure 1 . distribution of schistosoma hematobium in six districts of afder and gode zones of somali region , ethiopia prior to this study , information was obtained from the somali regional health bureau that schistosomiasis was observed in the area . our study showed a prevalence rate of 16% of urinary schistosomiasis among the school - aged children in the defined area . the result is lower than the study done in two communities of southern darfur which showed a prevalence of 56% . in 2002 , a survey conducted in gode zone ( kelafo and mustahil districts ) in ethiopia reported a prevalence of 68% . almost a decade before , a different study found a prevalence of 63.0% was recorded in the same districts . currently in ethiopia , there is no national schistosomiasis control program and the distribution of schistosomiasis is not yet mapped . therefore , the findings of this study can guides interventions in these districts and contribute information for the national mapping initiative . the prevalence rates of the disease were not uniform across the various six communities studied ( x = 208.8 , p < 0.0001 ) , and this might be due to previous mass drug administration ( 3 years earlier ) by medecins sans frontieres in cherti and hargele districts . there was no significant difference in age group in s. haematobium infection observed in our study ( p > 0.05 ) . the prevalence showed an increasing trend with increasing age and it peaked around 11 - 13 years and then started to decline . in older adults , no significant change is found in the prevalence of disease , but the parasite burden or the intensity decreases . in our study , males had higher risk of s. haematobium infection compared with female ( or = 1.68 , 95% c.i ; 1.1 - 2.7 ) . in contrast , a study in ghana showed no statistical significant association between infection with s. haematobium and sex ( p > 0.05 ) . the difference in risk of infection with gender in our study could be attributed to pastoralist duties of males in somali society , which leads to high frequency of water contact . there was no previous health facility report on s. mansoni infection and our study did not find a single case of s. mansoni . the study has a number of limitations and its findings should be interpreted in the light of these limitations . first of all , we have not collected data on the environment and lifestyle characteristics of the participants which could act as cofounder and affect interpretation . the findings of this study suggest that s. haematobium is endemic in the districts of gode and afder zones and that there is a high prevalence of infection among males as compared with females . the most important effects of schistosomiasis are the late complications that arise from chronic infection . mustahil district is a high - risk community ; therefore , treatment should be given once a year to all school - aged children ( enrolled and not enrolled ) and adults - at - risk ( pregnant and lactating women ; groups with occupations involving contact with infested water , such as fishermen , farmers , irrigation workers , or women in their domestic tasks ) , and to entire communities living in the area . kelafo district is a moderate risk community ; therefore , treatment should be given every 2 years to all school - aged children ( enrolled and not enrolled ) and adults at risk . hargele and cheriti districts are low - risk communities ; therefore , treatment should be given twice during primary schooling age ( e.g. , once on entry and exit ) to all school - aged children ( enrolled and not enrolled ) according to the world health organization guidelines on preventive chemotherapy on human helminthiasis .
background : there is no recent information about the prevalence and distribution of schistosomiasis in the somali national regional state of ethiopia . 
 ethiopia launched the national integrated neglected tropical diseases ( ntds ) master plan in june 2013 . 
 the master plan identified mapping ntds as a prerequisite for launching control programs . 
 therefore it is important to understand the prevalence and distribution of schistosomiasis in respective regions.materials and methods : from february to march 2011 , a cross - sectional survey was done in school - aged children from six districts of afder gode zone . 
 urine samples were collected and examined for ova of schistosoma haematobium using the sedimentation technique and stool samples were collected and examined for s. mansoni using the kato - katz technique . 
 a semistructured questionnaire was used to collect sociodemographic characteristics of the participants.results:of the 523 children , 513 ( 98% ) of them participated in the study . 
 the prevalence of s. haematobium was 16.0% ( 95% confidence interval ( ci ) ; 12.8 - 19.2 ) . 
 the rate of the disease was not uniform across the various six communities studied ( x2 = 208.8 , p < 0.0001 ) . 
 musthail district had the highest prevalence with 64.2% ( 95% ci ; 60.0 - 68.3 ) followed by kelafo with 11.8% ( 95% ci ; 9.0 - 14.6 ) . 
 no infections of s. mansoni were found in these settings . 
 there was no difference in the prevalence of infection across age groups . 
 boys were more likely to be infected by s. haematobium than girls ( odds ratio = 1.68 ; 95% ci : 1.1 - 2.7).conclusion : s . 
 haematobium infection is prevalent in the region with varying distribution across the districts . according to the world health organization , mass drug administration 
 should be considered in some of the districts .