Inadequate water supply and sanitation adversely affects the health and socio-economic development of communities and places them at risk of contracting schistosomiasis and soil-transmitted helminths (STHs). The aim of this study was to quantify the prevalence and intensity of schistosomiasis (bilharzia) and STHs amongst female school-going pupils in Ugu district.
A descriptive cross-sectional study was conducted in Ugu district amongst primary school pupils from 18 randomly selected schools in 2010. A structured questionnaire was used to collect information on the history and knowledge of bilharzia of 1057 pupils. One stool and 3 consecutive days of urine samples were collected per participant and screened for helminth ova. Findings were compared with those reported by the parasite control programme, which collected data in the same area in 1998.
The prevalence of
Female pupils in rural schools remain at risk. A mass treatment campaign, increased public awareness and improved sanitation are required to reduce these infections and sustain a reduction of STHs and schistosomiasis.
prevalence; intensity; schistosomiasis; soil-transmitted helminths;
The global prevalence of urogenital schistosomiasis (
An estimated 4.5 billion people are infected with one of the three common soil-transmitted helminth (STH) species, namely the roundworm (
In general, the growth and survival of schistosome parasites and their snail intermediate hosts are sensitive to changes in weather patterns.
In 1938 and confirmed in the 1980s, the distribution of
Humid, warm and moist temperatures in these regions
A cross-sectional study was conducted in the Ugu district on the south coast of the province of KwaZulu-Natal, South Africa, between January and November 2010. Details about the study area are discussed elsewhere.
Schools were randomly selected to participate in the study based on the distance from the coast (> 10 km), using the altitude map to locate potential schools situated below 300 m because schistosomiasis prevalence decreases with an increase in altitude.
Urine samples were collected per participant on three consecutive days, requiring each school to be visited on three occasions. Clean pre-labelled ‘honey’ jars with unique identity numbers were used to collect urines between 10:00 and 14:00 h each day. One stool sample was collected per participant in a pre-labelled specimen jar. The collected samples were packed in cooling boxes with ice packs to maintain temperatures around 4 °C. They were transported to the laboratory that had been set up in the field for processing by trained research assistants on the same day.
The prevalence and intensity of the helminth infections were analysed using univariate analysis. All data were entered and analysed using the Statistical Programme for Social Sciences version 18 (SPSS 18) statistical package. A χ2 test was used to analyse associations between the prevalence of schistosomiasis and factors such as knowledge about schistosomiasis and reporting red urine, and between the different helminth infections. The value
This study was given ethical clearance by the University of KwaZulu-Natal’s Biomedical Research Ethics Committee (Ref: BF005/12). The Departments of Health and Education in Ugu district, KwaZulu-Natal, also gave permission for this study. All subjects found positive for urinary and intestinal schistosomiasis were treated with single dose (40 mg/kg) praziquantel, and those infected with soil-transmitted helminths were referred to primary health clinics (PHC) for treatment, because PHC clinics held stocks of the latter.
Female pupils (
Prevalence and intensity of
Number of urine samples collected | Mean intensity eggs per 10 mL (s.d.) |
|||
---|---|---|---|---|
% | s.d. | Mean intensity | ||
Pupils ( |
7 | 24.1 | 44 | 10.6 |
Pupils ( |
36 | 24.0 | 60 | 18.3 |
Pupils ( |
269 | 34.0 | 32 | 9.6 |
Total urine samples ( |
312 | 32.2 | 57 | 16.7 |
s.d., standard deviation.
The prevalence of pupils found to be infected with
Prevalence of Schistosoma haematobium, Ascaris lumbricoides and Trichuris trichiura amongst pupils (aged 10–12 years) attending 18 rural KwaZulu-Natal primary schools.
Pupils count per school | Prevalence (%) of S. haematobium ( |
95% CI | Prevalence (%) of A. lumbricoides ( |
95% CI | Prevalence (%) of T. trichiura ( |
95% CI | |
---|---|---|---|---|---|---|---|
School | |||||||
A | 100 | 43 | 33–56 | 35 | 25–45 | 42 | 32–52 |
B | 71 | 40 | 25–56 | 32 | 14–33 | 28 | 1–30 |
C | 37 | 50 | 27–73 | 40 | 22–61 | 25 | 6–28 |
D | 114 | 38 | 26–52 | 26 | 17–38 | 48 | 36–61 |
E | 11 | 20 | 3.6–62 | 11 | 2–43 | 22 | 6–55 |
F | 50 | 20 | 11–35 | 25 | 15–39 | 27 | 17–41 |
G | 37 | 36 | 20–55 | 19 | 9–35 | 19 | 9–39 |
H | 101 | 47 | 36–57 | 24 | 16–35 | 37 | 27–47 |
I | 44 | 48 | 33–62 | 37 | 24–52 | 29 | 18–44 |
J | 46 | 54 | 39–68 | 38 | 25–52 | 47 | 33–61 |
K | 172 | 11 | 7–16 | 19 | 14–26 | 16 | 12–23 |
L | 77 | 17 | 9–29 | 19 | 11–30 | 21 | 13–32 |
M | 63 | 8 | 2.6–20 | 27 | 17–40 | 14 | 7–24 |
N |
34 | 13 | 5–29 | 20 | 10–37 | 17 | 14–44 |
O |
22 | 10 | 3–30 | 15 | 5–37 | 5 | 1–24 |
P |
7 | 25 | 5–70 | 16 | 3–56 | 0 | 0–4 |
Q |
42 | 9 | 3–23 | 0 | 0–10 | 0 | 0–10 |
R |
7 | 67 | 36–92 | 14 | 3–51 | 0 | 0–35 |
CI, confidence interval.
, The last five schools had few pupils as these schools were affected by the teachers’ strike (2010) and were visited during the time teachers were trying to catch up the lost time and preparing for final exams.
The mean intensity for pupils infected with
Mean intensity (eggs per gram) of
School ID ( |
||||||
---|---|---|---|---|---|---|
Eggs per 10 mL urine | ± s.d. | Eggs per gram | ± s.d. | Eggs per gram | ± s.d. | |
Overall 18 schools | 17 | 56 | 4110 | 14 841 | 146 | 641 |
School A (100) | 19 | 47 | 4956 | 12 403 | 188 | 411 |
School B (71) | 7 | 12 | 9640 | 26 182 | 139 | 350 |
School C (37) | 23 | 38 | 7091 | 17 274 | 49 | 88 |
School D (114) | 31 | 81 | 9689 | 37 928 | 141 | 449 |
School E (11) | 1 | 3 | 1951 | 5853 | 102 | 246 |
School F (50) | 47 | 121 | 2762 | 6142 | 140 | 554 |
School G (37) | 11 | 46 | 2380 | 5928 | 231 | 1006 |
School H (101) | 30 | 70 | 2229 | 5490 | 319 | 1305 |
School I (44) | 40 | 98 | 5197 | 8408 | 41 | 82 |
School J (46) | 32 | 66 | 5635 | 8569 | 253 | 791 |
School K (172) | 4 | 16 | 2239 | 5684 | 116 | 602 |
School L (77) | 4 | 11 | 2691 | 6386 | 85 | 208 |
School M (63) | 3 | 12 | 4446 | 8127 | 133 | 535 |
School N |
7 | 20 | 1726 | 4775 | 197 | 967 |
School O |
0.44 | 1 | 2097 | 5811 | 17 | 76 |
School P |
54 | 99 | 210 | 514 | 0 | 0 |
School Q |
0.86 | 0.3 | 0 | 0 | 0 | 0 |
School R |
14.8 | 17 | 2857 | 7559 | 0 | 0 |
s.d., standard deviation.
, The last five schools had low number of pupils as these schools were affected by the teachers’ strike (2010) and were visited during the time teachers were trying to catch up the lost time and preparing for final exam.
Fifteen of the schools had pupils infected with both ascariasis and trichuriasis and two schools had pupils infected with one helminth species. There was a statistically significant association between the prevalence of
The burden of ascariasis and schistosomiasis varied per school from those with a low mean intensity (210 eggs per gram) to moderate infection (9689 eggs per gram). For trichuriasis, the intensity of infection in all schools was low (
All dual infection cases had moderate to high intensities of infection (
Intensity of infection amongst dual- and triple-infected pupils from 18 Ugu district primary schools (
Infection category | Helminth | Number of infected pupils | Mean intensity | ± s.d. |
---|---|---|---|---|
Dual infection | 116 | - | - | |
- | 619 eggs per gram | 1250 | ||
- | 16 689 eggs per gram | 19 189 | ||
Dual infection | 85 | - | - | |
- | 441 eggs per gram | 844 | ||
- | 81 eggs per 10 mL | 117 | ||
Dual infection | 69 | - | - | |
- | 70 eggs per 10 mL | 70 | ||
- | 15 783 eggs per gram | 16 732 | ||
Triple infection | 44 | - | - | |
- | 90 eggs per 10 mL | 117 | ||
- | 17 819 eggs per gram | 18 456 | ||
- | 552 eggs per gram | 905 |
s.d., standard deviation.
Pupils’ knowledge and reported history of
Question | Response | % | ||
---|---|---|---|---|
Know what bilharzia is |
1020 | - |
- |
- |
History of bilharzia within family |
1022 | - |
- |
- |
Ever had bilharzia |
1020 | - |
- |
- |
Ever treated for bilharzia |
237 | - |
- |
- |
, Variable significant association with prevalence of
There had been a reduction of more than half in the prevalence of both
The PCP study was conducted in the same area and reported a mean egg count of 22.5, s.d. 57.2 eggs per 10 mL urine for
Comparison of prevalence and intensity of helminth infections and water contact in 1998 and 2010 studies in Ugu district.
Infection and water contact status | 1998 ( |
2010 ( |
||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
% | 95% CI | Eggs per 10 mL urine | Eggs per g stool | % | 95% CI | Eggs per 10 mL urine | Eggs per g stool | |||||
s.d. | s.d. | s.d. | s.d. | |||||||||
15 | 12–19 | - | - | - | - | 32.2 | 29–35 | - | - | - | - | |
62 | 58–67 | - | - | - | - | 24.5 | 22–27 | - | - | - | - | |
59 | 54–63 | - | - | - | - | 25.9 | 23–29 | - | - | - | - | |
- | - | 22.5 | 57 | - | - | - | - | 16.7 | 56 | - | - | |
- | - | - | - | 73 | 64 | - | - | - | - | 4110 | 14 841 | |
- | - | - | - | 65 | 60 | - | - | - | - | 146 | 642 | |
Fetch water from river | 72 | 67–76 | - | - | - | - | 8.0 | 6–10 | - | - | - | - |
Wash clothes in river | 44 | 39–49 | - | - | - | - | 12.0 | 10–15 | - | - | - | |
Swim in the river | 48 | 43–53 | - | - | - | - | 0.5 | 0.2–1 | - | - | - | - |
Play in the river | 47 | 43–53 | - | - | - | - | 0.5 | 0.2–1 | - | - | - | - |
Other water contact |
11 | 8–15 | - | - | - | - | 63.0 | 60–66 | - | - | - | - |
Note: Data from 1998 is from unpublished findings from the Parasite Control Program.
s.d., standard deviation; CI, confidence interval.
, Unlisted freshwater contact.
A third of pupils investigated tested positive for
The high variability of multiple
There has been a decrease in the prevalence of STH infections since the PCP study, which was initiated in 1998 and concluded in the year 2000.
South Africa has a history of endemicity of STH infections.
Studies conducted in other parts of the province of KwaZulu-Natal in the past have reported prevalence similar or higher to those in this study. In a study that investigated the prevalence of ascariasis and other helminths in children attending a rural KwaZulu-Natal hospital and its referring clinic, 38.0% and 22.0% were found to be positive for
These health problems can be reversed by administering the recommended treatment for STHs (mebendazole or albendazole) and for schistosomiasis (praziquantel) using the correct dose (40 mg/kg). However, if untreated, the damage caused by urogenital schistosomiasis cannot be reversed even though egg deposition can be reduced significantly. Urogenital schistosomiasis can result in bladder, ureter and kidney diseases, which are often diagnosed at the later stages of infection. Bladder cancer is another possible late-stage complication. In women, urogenital schistosomiasis may lead to genital lesions, vaginal bleeding, pain during sexual intercourse and infertility.
In coastal Kenya, age-stratified analysis (< 12 years) showed that overall children in the older (12–20 years) age groups had less infection than those in the younger (5–11 years) age groups, although at the outset of the programme in 1984, the older children had the higher prevalence (71%) compared with the younger age groups (63%).
The majority of cases found in our study were light infections. These findings are in agreement with the findings from the PCP study that reported overall light and moderate intensity of infections.
Soil transmitted helminths eggs can survive 10–12 months in the soil upon excretion in tropical climate conditions
Only female pupils aged 10–12 years were included in our study as compared to both boys and girls from ages 5–17 years. Previous studies have reported that children aged 9–13 years are most vulnerable and most likely to contact helminths infection; hence, our study focused on the most vulnerable age group making it possible to arrive to general conclusion about prevalence status of all children including boys. Also, we are able to draw conclusion for both boys and girls using evidence from findings from previous studies which show that both boys and girls are infected by helminths similarly.
Towards the end of 2010, there was massive teachers’ strike that lasted for couple of weeks towards the end of the academic year. This strike meant that the interaction we had with schools was very limited when the strike was over as teachers were making up for the lost time and also preparing for final exams. This led to last five schools we visited having low participants. This was noted in our findings.
The following recommendations were made. To achieve maximum health impact, greater focus is needed in ensuring installation of safe hygienic toilets and safe water for personal and domestic hygiene in communities.
Proper sanitation facilities should be installed at the same time as water facilities to significantly effect optimum reduction of water-faecal-related infections. Access to water supply should be as close as possible to each house to reduce the exposure to unsafe water sources and maximise hygiene practices. School and health programmes should emphasise hygiene education to encourage personal hygiene and promote early health-seeking behaviour. Pupils and communities should be engaged about infections or diseases that are endemic in their communities and collective solutions should be explored as to how such diseases can be prevented from spreading.
The authors would like to thank Mr Roy Manyaira for data management and the team at the Bilharzia Research Improving Global Health Today (BRIGHT) Research Clinic (
The authors have declared that no competing interests exist.
E.F.K., M.T. and S.G.G. designed and conceived the study. S.G.Z. and E.F.K. conducted the study and collected data. S.G.Z., M.T. and E.F.K. analysed the data. S.G.Z. wrote the article. All authors read, reviewed and approved the final manuscript.
This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.
This study is a part of a larger ongoing study and, therefore, data are not available for public purpose.
The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of any affiliated agency of the authors.