A national survey of the prevalence of schistosomiasis and soil transmitted helminths in Malaŵi

Bowie, Cameron; Purcell, Bernadette; Shaba, Bina; Makaula, Peter; Perez, M. Arantza

doi:10.1186/1471-2334-4-49

Cited by 52 publications

(76 citation statements)

References 9 publications

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“…This may be due to differences in exposure (due to behavioural differences, particularly with respect to water contact), physiological changes at puberty leading to lower susceptibility (including interactions between hormonal, anatomical and immunological changes), and the development of acquired immunity (Feldmeier et al 1998;Fulford et al 1998;Mutapi et al 2006). Higher prevalence and intensity of infection has been reported in males than females (Ansell et al 2001;Ndyomugyenyi & Minjas 2001;Bowie et al 2004), though exceptions have also been reported (Mafe et al 2000). For S. haematobium and S. mansoni (which has similar age-gender patterns), different immune responses between the sexes have been argued to be an important contributor to observed differences in intensity of infection (Marguerite et al 1999;Remoué et al 2001).…”

Section: Introductionmentioning

confidence: 94%

“…Population age profiles among schoolaged children (as defined by parasitological field surveys) typically show an increase in prevalence and intensity of infection from the youngest age groups to the early teens, and often a subsequent decline in the mid to late teens (Booth et al 1998;Ndyomugyenyi & Minjas 2001;Bowie et al 2004;Clennon et al 2004). This may be due to differences in exposure (due to behavioural differences, particularly with respect to water contact), physiological changes at puberty leading to lower susceptibility (including interactions between hormonal, anatomical and immunological changes), and the development of acquired immunity (Feldmeier et al 1998;Fulford et al 1998;Mutapi et al 2006).…”

Section: Introductionmentioning

confidence: 99%

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Age and gender effects in self‐reported urinary schistosomiasis in Tanzania

Clements

Barnett

Nyandindi

et al. 2008

Tropical Med Int Health

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Summaryobjectives To characterize age-gender prevalence profiles of urinary schistosomiasis according to the questionnaire responses, compare the profiles to field survey data from selected regions, and determine if the profiles varied spatially throughout Tanzania.methods In 2004, a national school-based questionnaire survey for self-reported schistosomiasis and blood in urine (BIU) was conducted in all regions of mainland Tanzania, to assist targeted mass distribution of praziquantel. Field survey data were collected in six north-western and five coastal regions using microscopic examination of urine samples for the presence of Schistosoma haematobium eggs and assessment of micro-haematuria with chemical reagent strips. Bayesian logistic regression models were created to calculate age-gender profiles adjusted for demographic and ecological covariates and spatial correlation in the questionnaire data. Separate odds ratios (OR) for age-gender effects were calculated in each administrative area.results Data were obtained from > 2.5 million schoolchildren. Boys had higher prevalence of selfreported schistosomiasis and BIU than girls. In boys, prevalence according to the questionnaire and field surveys followed similar age profiles. However, in girls, prevalence according to the field surveys increased in older age groups, but flattened out or decreased according to the questionnaire, indicating the latter underestimated prevalence in older girls. In the models, little spatial correlation was evident in the OR for the age-gender effects, suggesting that these did not vary spatially.conclusion Age-gender patterns of urinary schistosomiasis were consistent in different geographical areas of Tanzania. Because the questionnaire underestimated prevalence in older girls, we propose that upward calibration of observed prevalence is done for older females only.

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Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Age and gender effects in self‐reported urinary schistosomiasis in Tanzania

Clements

Barnett

Nyandindi

et al. 2008

Tropical Med Int Health

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“…This questionnaire was generating with the guidance of WHO guidelines and previous similar studies. 7,11 Specimen collection and parasitological analysis…”

Section: Data Collectionmentioning

confidence: 99%

“…5 A 1996 study that assessed resident expatriates in Malawi who had visited the lake found a prevalence of 33%. 6 Although the 2002 National Survey on Schistosomiasis and Soil-transmitted Helminths found a national schistosomiasis prevalence of 6.9%, 7 and a 2006 Blantyre study found a prevalence of 10.4% among school children, 8 high prevalence rates persist in communities along Lake Malawi, especially along the southern part. A Nankumba Peninsula study among school children in lakeshore villages found a schistosomiasis prevalence of 36.5% in 2003, and 23.7% in 2007, with reinfection rates of 30% to 40%, a year after treatment.…”

Section: Introductionmentioning

confidence: 99%

Prevalence and distribution of <i>Schistosoma haematobium</i> infection among school children living in southwestern shores of Lake Malawi

Kayuni

Peeling

Makaula³

2017

Mal. Med. J

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BackgroundThe prevalence of Schistosoma haematobium infection has been shown to be about 23.7% among children living in the lakeshore areas of Malawi, with reinfection rates of about 30% to 40%. This study aimed to determine the current prevalence and distribution of S. haematobium infection in school children along the southwestern shores of Lake Malawi and examine the control interventions present in the area. MethodsThis prospective cross-sectional study was conducted in primary schools. School children were enrolled, demographic data were collected, and urine samples were submitted for analysis on macrohaematuria, microhaematuria, and S. haematobium eggs. A questionnaire was administered to 3 health facilities on diagnosis and treatment of schistosomiasis, as well as the control interventions against it. ResultsFour hundred children (174 males and 226 females) were enrolled from 7 primary schools. Mean participant age was 9.57 years (range 7 to 12 years). Fifty children (12.5%) had S. haematobium eggs detected in their urine, with the mean egg count being 15/10 mL. The highest infection intensity category (≥ 50 eggs/10mL) was seen in 10 children (2.5%). Prevalence varied significantly between the schools, with rates ranging from 0% to 20%. Schools with higher prevalence rates were located farther away from the nearest public hospital that provides treatment free of charge. Prevalence correlated with previous history of mass chemotherapy in schools. Mass chemotherapy, health education, and improved water supply and sanitation were some of the interventions that contributed to lower prevalence rates in some areas. ConclusionsSchistosomiasis prevalence around southwestern Lake Malawi was lower than previously reported, owing to control interventions focusing on health education, improved water supply, sanitation, and mass chemotherapy. Consistent and uniform interventions can reduce prevalence further and sustain control. As prevalence falls, diagnostics can identify high transmission areas, monitor disease trends, and guide evidence-based control strategies.

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“…[11][12][13][14][15][16] Estimates of its prevalence vary across Malawi, 17 with some estimates suggesting that 40% to 50% of Malawians are infected. 2,9,18 It has been suggested that these estimates were derived from studies conducted too long ago (in the 1990s) to be valid now, and that they were skewed by a selection bias for high-risk areas. 2,9 This suggests that more up-to-date local estimates would be more helpful for planning of control strategies.…”

Section: Introductionmentioning

confidence: 99%

Urinary schistosomiasis among preschool children in Malengachanzi, Nkhotakota District, Malawi: Prevalence and risk factors

Moyo¹,

Changadeya²,

Chiotha³

et al. 2016

Mal. Med. J

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AimThis study was designed to determine the prevalence of and risk factors for schistosomiasis among a group of preschool children in Malawi. Schistosomiasis burden among preschoolers in Malawi is not well documented in the literature. MethodsThis study used field research (in the form of a snail survey), laboratory work (urinalysis and microscopy for parasite identification), and questionnaireguided interviews to determine the prevalence of and risk factors for urinary schistosomiasis among children, aged between 6 and 60 months, in Malengachanzi, Nkhotakota District, Malawi. ResultsUrinary schistosomiasis prevalence among preschool children was 13%. Of the factors evaluated, only age (P = 0.027) was statistically significantly associated with urinary schistosomiasis risk. Four-year-old preschool children were five times more likely to contract urinary schistosomiasis than twoyear-old children (odds ratio [OR] = 5.255; 95% confidence interval [CI] = 1.014-27.237; P = 0.048). Increased contact with infested water among older children likely explains much of their increased risk. Infestation was evidenced by the presence of infected Bulinus globosus snails in the water contact points surveyed. Multiple regression analysis showed that visiting water contact sites daily (OR = 0.898, 95% CI = 0.185-4.350, P = 0.894), bathing in these sites (OR = 9.462, 95% CI = 0.036-0.00, P = 0.430) and lack of knowledge, among caregivers, regarding the causes of urinary schistosomiasis (OR = 0.235, 95% CI = 0.005-1.102, P = 0.066) posed statistically insignificant risk increases for preschoolers contracting urinary schistosomiasis. ConclusionsUrinary schistosomiasis was prevalent among preschool children in Malengachanzi, Nkhotakota District. Contact with infested water puts these children and the general population at risk of infection and reinfection. Inclusion of preschool children in treatment programmes should be considered imperative, along with safe treatment guidelines. To prevent infection, the population in the area should be provided with health education and safe alternative water sources.

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A national survey of the prevalence of schistosomiasis and soil transmitted helminths in Malaŵi

Cited by 52 publications

References 9 publications

Age and gender effects in self‐reported urinary schistosomiasis in Tanzania

Age and gender effects in self‐reported urinary schistosomiasis in Tanzania

Prevalence and distribution of <i>Schistosoma haematobium</i> infection among school children living in southwestern shores of Lake Malawi

Urinary schistosomiasis among preschool children in Malengachanzi, Nkhotakota District, Malawi: Prevalence and risk factors

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