The impact of caregiver mental health on child prosocial behavior: A longitudinal analysis of children and caregivers in KwaZulu-Natal, South Africa.

BACKGROUND: Prosocial behavior has positive social, cognitive, and physical health effects on the individual exhibiting the behavior as well as on society as a whole, and is integral to overall mental and physical wellbeing. The development of prosocial behavior is rooted in early childhood and learned through observation. As such, those spending time with children, especially their caregiver, play a critical role in their prosocial development. The current study investigates the impact of caregiver mental health on the prosocial development of young children over time. METHODS: This paper presents a secondary analysis of child prosocial development in the Asenze Study, a longitudinal, population-based cohort study based in KwaZulu-Natal, South Africa. Children were followed-up over time from an average age of five to seven years along with their caregivers. Linear GEE regression analysis was used to assess whether a change in presence of a mental health disorder in a caregiver during this 2-year interval (using the Client Diagnostic Questionnaire) impacted the development of their child's prosocial behavior (using the Strengths and Difficulties Questionnaire). RESULTS: After adjusting for early child-care, child HIV status, SDQ child prosocial subscale, SDQ total difficulties score, and household order score (CHAOS), children whose caregivers acquired a mental health disorder had a significantly smaller increase in prosocial behavioral development compared to children whose caregivers never had a mental health disorder. CONCLUSIONS: Identifying contextually relevant modifiable factors such as this will help stimulate the development of interventions to promote prosocial development in childhood.

The impact of family support and organization on adolescents during school closure under Covid-19 lockdown regulations in an area of South Africa.

The Covid-19 pandemic and resultant disruptions to schooling presented significant challenges for many families. Well organised families have been shown to have a protective effect on adolescent wellbeing in periods of shock. At the onset of the Covid-19 pandemic, Asenze, a population-based cohort study, was conducting a third wave of data collection in peri-urban South Africa, examining risk and protective factors during adolescence. By March 2020, n = 272 adolescents and their caregivers (n = 241) in the cohort had been assessed when in-person data collection was halted by lockdown measures countrywide. During this cessation we undertook a brief telephonic qualitative sub-study to explore whether families enrolled in the cohort were able to cohabit cohesively and undertake distance learning during lockdown. A purposeful sample of 20 families (caregivers n = 20, adolescents n = 24) recently assessed in the Wave 3 of the main study, participated in semi-structured interviews. Quantitative data from Waves 1-3 of the main study was used to measure family function, adolescent cognitive function, and profile adolescent and caregivers. The quantitative and qualitative data were integrated to illustrate the dynamics of the participants' lives before and during lockdown. We found that families classified as well-organized before lockdown, were more likely to report co-operation during lockdown. Adolescents who were self-motivated, had access to smartphones or the internet, and were supported by both family and educators, were well-placed to continue their education without much disruption. However, few schools instituted distance learning. Of the adolescents who were not assisted- some studied on their own or with peers, but others did no schoolwork, hindered by a lack of digital connectivity, and poor service delivery. The experience of adolescence and caregivers in the Asenze Cohort during lockdown highlight the importance of family functioning for adolescent wellbeing in crisis, as well as the need for access to health, mental health, and social services, communication upgrades, and enhancements to the education system during peaceful times, to make a difference to young lives in times of crisis.

The Asenze Cohort Study in KwaZulu-Natal, South Africa: protocol and cohort profile.

The Asenze cohort is set in South Africa, a middle-income country impacted by one of the highest global rates of people living with HIV/AIDS and high levels of socioeconomic inequality. This longitudinal population-based cohort of children and their primary caregivers assesses household and caregiver functioning, child health, social well-being, and neuro-development from childhood through adolescence. Almost 1,600 children born at the peak of the human immunodeficiency virus epidemic (2003-2005) were followed (with their primary caregivers) in 3 waves, between 2008 and 2021, at average ages of 5, 7, and 16. Wave 3 is currently underway, having assessed over 1,100 of the original wave 1 children. Wave 4 begins in 2022. The study, with a dyadic structure, uses a broad range of measures, validated in South Africa or recommended for global use, that address physical, social and neuro-development in childhood and adolescence, and the social, health, and psychological status of children's primary caregivers. The Asenze study deepens our understanding of childhood physical, cognitive, and social abilities and/or disabilities, including risk-taking behaviors, and biological, environmental, and social determinants of health. We anticipate the findings will contribute to the development of community-informed interventions to promote well-being in this South African population and elsewhere.

Adverse childhood experiences (ACEs) and child behaviour problems in KwaZulu-Natal, South Africa.

BACKGROUND: Adverse childhood events (ACEs) are associated with negative health effects in adulthood. Despite knowledge of these later impacts, little is known about the earlier effect of ACEs on later child behaviour in low- and middle-income countries (LMIC). METHODS: The population-based Asenze cohort study was implemented in a peri-rural area of KwaZulu-Natal, South Africa, comprising five Zulu tribal areas. Two waves of data were examined: family information and ACEs exposure when children were on average 5 years old and child behaviour problems (Strengths and Difficulties Questionnaire [SDQ]) approximately 2 years later (average age 7 years). Logistic regression analysis was used to examine unadjusted and adjusted relationships between cumulative ACEs experienced and the SDQ total scores (dichotomized as top 10% vs. the rest) as well as selected SDQ subscales. RESULTS: A significant relationship between increased ACE exposure and SDQ total score was observed. The same relationship was also seen for the SDQ emotional symptoms and conduct problem subscales, but not for hyperactivity. The results of a sensitivity analysis excluding intimate partner violence from the ACEs measure demonstrated similar results. CONCLUSIONS: There is an association between exposure to ACEs and later child behaviour problems within this LMIC population demonstrating an early negative impact for ACEs. While previous research has focused on the effects of ACEs on adult health, this study provided evidence for an earlier relationship between ACEs and child behaviour problems that may be a part of the mechanism through which later health effects arise.

Engaging future healthcare professionals for rural health services in South Africa: students, graduates and managers perceptions.

BACKGROUND: The shortage of healthcare professionals (HCP) negatively affects health services in rural areas in many parts of the world, as is the case in South Africa. Innovative programs designed to improve the recruitment strategies for health system in a rural area are essential. They need support with a scholarship and mentorship programme for young people from rural areas to study for health science degrees, with the aim that they would take up a post at the hospital in their community, once qualified. This paper reports the perceptions and experiences of the students and graduates sponsored by the foundation, and those of managers from the facilities where the students were ultimately placed, in order to gauge whether such a programme can make a sustainable contribution to address the shortage of health personnel in rural areas and to what extent this is happening. METHODS: The authors used qualitative methods, combining semi-structured in-depth interviews and focus groups and the data were analyzed thematically. RESULTS: The results provide information on students interviewed who appreciated the financial and socio-emotional support that they received. On the other hand, graduates value the availability of jobs in their home community on completion of their studies. The managers reported the success of the programme in increasing the number of healthcare personnel at the hospitals, and the increased range of available medical services. Since the graduates are familiar with the language and culture of their patients the managers considered that they are better able to assist them. CONCLUSIONS: The system was well thought-out and achieved its goal of improving health services in an underdeveloped rural area of South Africa. More could be achieved if other government services in the area were simultaneously improved and if the system were replicated elsewhere. The students and graduates from rural areas are involved on sustaining health services in rural areas while rural managers support the programme and make suggestions for improvement and to promote the program in other regions.

Cognitive and Language Development at Age 4-6 Years in Children HIV-Exposed But Uninfected Compared to Those HIV-Unexposed and to Children Living With HIV.

Perinatal HIV infection is associated with delayed neurocognitive development, but less is known about children perinatally HIV-exposed but uninfected (CHEU). We compared cognitive and language outcomes in 4-6-year old CHEU versus children HIV-unexposed and uninfected (CHUU) and children living with HIV (CLHIV). We enrolled 1,581 children (77% of the child population) in five communities in KwaZulu-Natal, South Africa. Children completed: Grover-Counter Scale of cognitive development, sub-scales of the Kaufman Assessment Battery for Children, Reynell Developmental Language Scales. HIV status of children and primary caregivers was determined by repeated rapid tests or report of prior testing. We conducted a cross-sectional multivariable linear regression on 922 dyads with complete data (257 CHEU, 627 CHUU, 38 CLHIV). On all outcome measures, CHEU and CHUU groups had comparable scores; CLHIV scored significantly lower. Emerging global progress toward the elimination of vertical HIV transmission may not only reduce mortality, but also positively impact child development.

Effect of small-quantity lipid-based nutrient supplements on growth, psychomotor development, iron status, and morbidity among 6- to 12-mo-old infants in South Africa: a randomized controlled trial.

Background: Evidence on the effect of small-quantity lipid-based nutrient supplements (SQ-LNSs) on early child growth and development is mixed. Objective: This study assessed the effect of daily consumption of 2 different SQ-LNS formulations on linear growth (primary outcome), psychomotor development, iron status (secondary outcomes), and morbidity in infants from age 6 to 12 mo within the context of a maize-based complementary diet. Methods: Infants (n = 750) were randomly assigned to receive SQ-LNS, SQ-LNS-plus, or no supplement. Both SQ-LNS products contained micronutrients and essential fatty acids. SQ-LNS-plus contained, in addition, docosahexaenoic acid, arachidonic acid (important for brain and eye development), lysine (limiting amino acid in maize), phytase (enhances iron absorption), and other nutrients. Infants' weight and length were measured bimonthly. At age 6 and 12 mo, psychomotor development using the Kilifi Developmental Inventory and South African Parent Rating Scale and hemoglobin, plasma ferritin, C-reactive protein, and α1-acid glycoprotein were assessed. WHO Motor Milestone outcomes, adherence, and morbidity were monitored weekly through home visits. Primary analysis was by intention-to-treat, comparing each SQ-LNS group with the control. Results: SQ-LNS-plus had a positive effect on length-for-age zscore at age 8 mo (mean difference: 0.11; 95% CI: 0.01, 0.22; P = 0.032) and 10 mo (0.16; 95% CI: 0.04, 0.27; P = 0.008) but not at 12 mo (0.09; 95% CI: -0.02, 0.21; P = 0.115), locomotor development score (2.05; 95% CI: 0.72, 3.38; P = 0.003), and Parent Rating Score (1.10; 95% CI: 0.14, 2.07; P = 0.025), but no effect for weight-for-age zscore. Both SQ-LNS (P = 0.027) and SQ-LNS-plus (P = 0.005) improved hemoglobin concentration and reduced the risk of anemia, iron deficiency, and iron-deficiency anemia. Both SQ-LNS products reduced longitudinal prevalence of fever, coughing, and wheezing but increased incidence and longitudinal prevalence of diarrhea, vomiting, and rash/sores. Conclusions: Point-of-use fortification with SQ-LNS-plus showed an early transient effect on linear growth and improved locomotor development. Both SQ-LNS products had positive impacts on anemia and iron status. This trial was registered at clinicaltrials.gov as NCT01845610.

Measurement of expressive vocabulary in school-age children: Development and application of the Kilifi Naming Test (KNT).

The dearth of locally developed measures of language makes it difficult to detect language and communication problems among school-age children in sub-Saharan African settings. We sought to describe variability in vocabulary acquisition as an important element of global cognitive functioning. Our primary aims were to establish the psychometric properties of an expressive vocabulary measure, examine sources of variability, and investigate the measure's associations with non-verbal reasoning and educational achievement. The study included 308 boys and girls living in a predominantly rural district in Kenya. The developed measure, the Kilifi Naming Test (KNT), had excellent reliability and acceptable convergent validity. However, concurrent validity was not adequately demonstrated. In the final regression model, significant effects of schooling and area of residence were recorded. Contextual factors should be taken into account in the interpretation of test scores. There is need for future studies to explore the concurrent validity of the KNT further.

Screening for developmental disabilities in HIV positive and HIV negative children in South Africa: Results from the Asenze Study.

BACKGROUND: While neurodevelopmental abnormalities are common in children with HIV infection, their detection can be challenging in settings with limited availability of health professionals. The aim of this study was to assess the ability to identify developmental disability among HIV positive and HIV negative children living in South Africa with an internationally used screen. METHODS AND FINDINGS: This analysis uses a sample of 1,330 4-6 year old children and 1,231 of their caregivers in KwaZulu-Natal, South Africa, including administration of the Ten Questions (TQ) screen, a standardized medical history and physical examination conducted by a medical doctor, with hearing and vision screening, psychological assessment for cognition and language delay, and voluntary HIV testing. There was a high prevalence of disability among the sample. Compared to HIV negative children, HIV positive children were more likely to screen positive on at least one TQ item (59.3 vs 42.8%, p = 0.01), be delayed in sitting, standing or walking (OR 3.89, 95% CI = 2.1-7.2) and have difficulty walking or weakness in the arms or legs (OR = 2.7, 95%CI = 0.8-9.37). By medical doctor assessment, HIV positive children were more likely to be diagnosed with gross motor disability (OR = 3.5, 95%CI = 1.3-9.2) and hearing disability (OR = 2.5, 95%CI = 1.2-5.3). By independent psychological assessment, HIV positive children were more likely to have cognitive delay (OR = 2.2, 95%CI = 1.2-3.9) and language delay (OR = 4.3, 95%CI = 2.2-8.4). Among HIV positive children, the sensitivity and specificity of the TQ for serious disability (vs. no disability) was 100% and 51.2%, respectively. Among HIV-negative children, the sensitivity and specificity of the TQ for serious disability (vs. no disability) was 90.2% and 63.9%, respectively. CONCLUSIONS: In this first report of the use of the TQ screen in the isiZulu language, it was found to have high sensitivity for detecting serious developmental disabilities in children, especially HIV positive children. The performance of the TQ in this sample indicates utility for making best use of limited neurodevelopmental resources by screening HIV positive children.

Infant Development at the Age of 6 Months in Relation to Feeding Practices, Iron Status, and Growth in a Peri-Urban Community of South Africa.

BACKGROUND: Evidence on the association between feeding practices, iron deficiency, anaemia, stunting, and impaired psychomotor development during infancy is limited. This study assessed the association between psychomotor development with early feeding practices, growth, iron status, and anaemia. METHODS: This was cross-sectional baseline data of a randomised controlled trial which included 6-month-old infants and their mothers or primary caregivers (n = 750) in a peri-urban community in the North West province of South Africa. The Kilifi Developmental Inventory and a parent rating scale were used to assess psychomotor development. Feeding practices and anthropometric measurements were based on the World Health Organisation (WHO) guidelines. Anaemia and iron status were determined by blood sample analysis. RESULTS: Prevalence of anaemia and stunting for the infants were 36.4% and 28.5%, respectively. Multiple regression analysis showed that birth weight was related to combined psychomotor scores (ß = -3.427 (-4.603, 1.891), p < 0.001), as well as parent rating scores (ß = -0.843 (-1.507, -0.180), p = 0.013). Length-for-age z-scores were associated with combined psychomotor scores (ß = -1.419 (-2.466, 0.373), p = 0.008), as well as parent rating scores (ß = -0.747 (-1.483, -0.010), p = 0.047). CONCLUSIONS: In this setting, with high prevalence of anaemia and stunting, important associations between lower psychomotor development scores and birthweight as well as length-for-age z-scores in 6-month-old infants were found. These findings warrant further investigation to develop a greater understanding of factors influencing the association between child growth and psychomotor development within the first 1000 days of life.

Mental health disorders among caregivers of preschool children in the Asenze study in KwaZulu-Natal, South Africa.

Given the existing evidence linking parental depression with infant and early child development, our aim was to describe the burden of mental health disorders among caregivers of young children aged 4-6 years living in an environment of poverty and high HIV seroprevalence. We analyzed baseline data from an epidemiologic study of the health and psychosocial needs of preschool-aged children. Primary caregivers of index children recruited from a household survey were screened for common mental disorders using the Client Diagnostic Questionnaire (CDQ). Sociodemographic, HIV and general health surveys were also conducted. Many caregivers (449/1,434; 31.3 %) screened positive for at least one psychiatric disorder on the CDQ, with post-traumatic-stress-disorder being the most common. Caregivers who screened positive for any disorder were more likely to be older, to have no individual sources of income and to have less formal education. Presence of a disorder was also significantly associated with lower employment levels within the household and death of a young child within the household. Known HIV-infected caregivers were more likely to have any mood disorder than caregivers who previously tested negative. The data support the need for mental health treatment interventions in South Africa, particularly interventions directed at PTSD and depression, and that take into account the high burden of poverty, HIV and childhood mortality. Given the limited formal mental health structure in South Africa to address these highly prevalent disorders; community-based mental health supports, available through decentralized health systems many be critical to delivering accessible interventions.

Effects of a multi-micronutrient-fortified beverage, with and without sugar, on growth and cognition in South African schoolchildren: a randomised, double-blind, controlled intervention.

Little is known about the effects of combined micronutrient and sugar consumption on growth and cognition. In the present study, we investigated the effects of micronutrients and sugar, alone and in combination, in a beverage on growth and cognition in schoolchildren. In a 2 × 2 factorial design, children (n 414, 6-11 years) were randomly allocated to consume beverages containing (1) micronutrients with sugar, (2) micronutrients with a non-nutritive sweetener, (3) no micronutrients with sugar or (4) no micronutrients with a non-nutritive sweetener for 8.5 months. Growth was assessed and cognition was tested using the Kaufman Assessment Battery for Children version II (KABC-II) subtests and the Hopkins Verbal Learning Test (HVLT). Micronutrients decreased the OR for Fe deficiency at the endpoint (OR 0.19; 95% CI 0.07, 0.53). Micronutrients increased KABC Atlantis (intervention effect: 0.76; 95% CI 0.10, 1.42) and HVLT Discrimination Index (1.00; 95% CI 0.01, 2.00) scores. Sugar increased KABC Atlantis (0.71; 95% CI 0.05, 1.37) and Rover (0.72; 95% CI 0.08, 1.35) scores and HVLT Recall 3 (0.94; 95% CI 0.15, 1.72). Significant micronutrient × sugar interaction effects on the Atlantis, Number recall, Rover and Discrimination Index scores indicated that micronutrients and sugar in combination attenuated the beneficial effects of micronutrients or sugar alone. Micronutrients or sugar alone had a lowering effect on weight-for-age z-scores relative to controls (micronutrients - 0.08; 95% CI - 0.15, - 0.01; sugar - 0.07; 95% CI - 0.14, - 0.002), but in combination, this effect was attenuated. The beverages with micronutrients or added sugar alone had a beneficial effect on cognition, which was attenuated when provided in combination.

S. haematobium as a common cause of genital morbidity in girls: a cross-sectional study of children in South Africa.

BACKGROUND: Schistosoma (S.) haematobium infection is a common cause of genital morbidity in adult women. Ova in the genital mucosal lining may cause lesions, bleeding, pain, discharge, and the damaged surfaces may pose a risk for HIV. In a heterogeneous schistosomiasis endemic area in South Africa, we sought to investigate if young girls had genital symptoms and if this was associated with urinary S. haematobium. METHODOLOGY: In a cross-sectional study of 18 randomly chosen primary schools, we included 1057 schoolgirls between the age of 10 and 12 years. We interviewed assenting girls, whose parents had consented to their participation and examined three urines from each of them for schistosome ova. PRINCIPAL FINDINGS: One third of the girls reported to have a history of genital symptoms. Prior schistosomal infection was reported by 22% (226/1020), this was associated with current genital symptoms (p<0.001). In regression analysis the genital symptoms were significantly associated both with urinary schistosomiasis (p<0.001) and water contact (p<0.001). CONCLUSIONS: Even before sexually active age, a relatively large proportion of the participating girls had similar genital symptoms to those reported for adult genital schistosomiasis previously. Anti-schistosomal treatment should be considered at a young age in order to prevent chronic genital damage and secondary infections such as HIV, sexually transmitted diseases and other super-infections.

Determinants of variability in motor performance in middle childhood: a cross-sectional study of balance and motor co-ordination skills.

BACKGROUND: Physical activity is a key component of exploration and development. Poor motor proficiency, by limiting participation in physical and social activities, can therefore contribute to poor psychological and social development. The current study examined the correlates of motor performance in a setting where no locally validated measures of motor skills previously existed. The development of an appropriate assessment schedule is important to avoid the potential misclassification of children's motor performance. METHODS: A cross-sectional study was conducted among a predominantly rural population. Boys (N = 148) and girls (N = 160) aged between 8 and 11 years were randomly selected from five schools within Kilifi District in Kenya. Four tests of static and dynamic balance and four tests of motor coordination and manual dexterity were developed through a 4-step systematic adaptation procedure. Independent samples t-tests, correlational, univariate and regression analyses were applied to examine associations between background variables and motor scores. RESULTS: The battery of tests demonstrated acceptable reliability and validity. Variability in motor performance was significantly associated with a number of background characteristics measured at the child, (gender, nutritional status and school exposure) household (household resources) and neighbourhood levels (area of residence). The strongest effect sizes were related to nutritional status and school exposure. CONCLUSIONS: The current study provides preliminary evidence of motor performance from a typically developing rural population within an age range that has not been previously studied. As well as being culturally appropriate, the developed tests were reliable, valid and sensitive to biological and environmental correlates. Further, the use of composite scores seems to strengthen the magnitude of differences seen among groups.

Schistosomiasis and Water-Related Practices in School Girls in Rural Kwazulu-Natal; South Africa

Abstract:There is increasing evidence of an association between female genital Schistosoma haematobium infection and HIV. In KwaZulu-Natal; we aimed to explore girls' water contact practice and to determine whether a study exclusively on girls would be manageable and welcomed. Three primary schools that had participated in a parasite control programme eight years prior were approached. Subject to consent; girls aged 9 to 12 years were interviewed on water-body contact; symptoms and household composition. Urine samples were analysed for S. haematobium infection eggs. Good dialogue was achieved in all schools and 95 consented to had an S. haematobium infection; geometric mean intensity 10.5 ova per 10 ml urine. Only 12participation; 43 had ever been treated for S. haematobium. Water-body contact was significantly associated with S. haematobium (OR 2.8; 95 CI 1.3-5.9; p= 0.008); however; S. haematobium was also found in 20 of girls who claimed to never have had water-body contact. Sixty-four percent thought they had no choice but to use unprotected water; 21 had no mother in the household; and being an orphan increased the risk of having S. haematobium. The community welcomed the study. Prevalence levels in South Africa are so high that some communities are eligible for WHO-recommended regular mass treatment

Effect of a fortified maize-meal porridge on anemia, micronutrient status, and motor development of infants.

BACKGROUND: Maize-meal porridge is used for infant feeding in many African countries, including South Africa. A low-cost, finely milled, maize-meal porridge was fortified with beta-carotene, iron, and zinc (100% of recommended dietary allowance), as well as ascorbic acid, copper, selenium, riboflavin, vitamin B-6, vitamin B-12, and vitamin E. OBJECTIVE: We assessed whether the fortified porridge could reduce anemia and improve the micronutrient status and motor development of infants. DESIGN: Infants aged 6-12 mo (n = 361) were randomly assigned to receive either the fortified or unfortified porridge for 6 mo. Primary outcomes were hemoglobin and serum retinol, zinc, and ferritin concentrations and motor development. Growth was assessed as a secondary outcome. Primary and secondary outcomes were assessed at baseline and 6 mo. RESULTS: Two hundred ninety-two infants completed the study. The fortified-porridge group had an intervention effect of 9.4 microg/L (95% CI: 3.6, 15.1 microg/L) for serum ferritin and 9 g/L (95% CI: 6, 12 g/L) for hemoglobin concentrations. The proportion of infants with anemia decreased from 45% to 17% in the fortified-porridge group, whereas it remained >40% in the control group. The fortified-porridge group achieved on average 15.5 of the 25 motor development score items, whereas the control group achieved 14.4 items (P = 0.007). Serum retinol concentration showed an inconsistent effect, and no intervention effect was observed for serum zinc concentrations. CONCLUSIONS: This low-cost fortified porridge can potentially have a significant effect in reducing anemia and improving iron status and motor development of infants in poor settings. The formulation needs some adjustment in terms of zinc fortification.

Ecologic covariates of hookworm infection and reinfection in rural Kwazulu-natal/south Africa: a geographic information system-based study.

Information on hookworm infection and re-infection in a cohort of primary school children and interview data on their socioeconomic background and behavior were combined with environmental data using a geographic information system (GIS). Multivariate models served to explore the covariation of environmental and infection patterns adjusted for possible confounders. Our aim was to identify environmental factors that might serve to predict infection and thus guide control efforts when epidemiologic information is insufficient. Furthermore, we wanted to establish whether soil type has a genuine influence on hookworm infection. Prevalence maps and spatial statistics showed considerable spatial clustering of infection in the small ( approximately 28 x 16 km) study area. The multivariate logistic regression models showed strong positive associations of infection at baseline (baseline prevalence = 83.2%) with settlement density (odds ratio [OR] = 1.24, 95% confidence interval [CI] = 1.10-1.38) and vegetation density (OR = 1.66, 95% CI = 1.25-2.22) and a strong negative association with the clay content of the soil (OR = 0.67, 95% CI = 0.62-0.73). Similar but weaker correlations were found after re-infection. Socioeconomic status and behavior did not seem to confound these associations. Spatial analysis of the model residuals suggested that because the models accounted for most of the spatial pattern, the model standard errors were not affected by spatial clustering. Our study shows that the pattern of hookworm infection is strongly influenced by several environmental factors. The GIS-aided prediction of areas in need of treatment is therefore a promising tool to guide control efforts when epidemiologic information is insufficient.

Ecological covariates of Ascaris lumbricoides infection in schoolchildren from rural KwaZulu-Natal, South Africa.

OBJECTIVES: To identify environmental factors that could serve to predict Ascaris lumbricoides infection patterns and thus guide control efforts in the absence of epidemiological information; to assess whether A. lumbricoides infection is positively associated with the soil clay content. METHODS: Information on A. lumbricoides infection and re-infection in a cohort of primary schoolchildren and interview data on their socioeconomic background and behaviour were combined with environmental data using a geographical information system (GIS). Multivariate models served to explore the covariation of environmental and infection patterns adjusted for possible confounders. RESULTS: Prevalence maps and spatial statistics revealed considerable spatial clustering of infection in the small study area. Logistic multivariate regression models showed strong positive associations of infection with vegetation density measured as the normalized difference vegetation index (NDVI) at baseline [odds ratio (OR) for a 10% increase: 1.82; 95% confidence interval (95% CI): 1.24-2.68; P=0.002] and after re-infection (OR: 2.22; 95% CI: 1.71-2.87; P<0.001). We also found a strong negative association of re-infection with the sun exposure of the soil surface as estimated from digital elevation models (OR: 0.78; 95% CI: 0.88; P<0.001). The soil clay content was only moderately positively associated with infection and re-infection. Socioeconomic and behavioural variables, although correlated with A. lumbricoides infection, did not appear to confound the above associations in the demographically homogeneous study area. Spatial analysis of the model residuals suggested that as the models accounted for most of the spatial pattern, the model standard errors should not be affected by spatial clustering. CONCLUSION: NDVI seems to have a high potential for the prediction of A. lumbricoides infection as it was strongly associated with infection patterns in the study area. Further advantages are that NDVI information is easy to use, affordable and available with global coverage.

Patterns of Schistosoma haematobium infection, impact of praziquantel treatment and re-infection after treatment in a cohort of schoolchildren from rural KwaZulu-Natal/South Africa.

BACKGROUND: Schistosomiasis is one of the major health problems in tropical and sub-tropical countries, with school age children usually being the most affected group. In 1998 the Department of Health of the province of KwaZulu-Natal established a pilot programme for helminth control that aimed at regularly treating primary school children for schistosome and intestinal helminth infections. This article describes the baseline situation and the impact of treatment on S. haematobium infection in a cohort of schoolchildren attending grade 3 in a rural part of the province. METHODS: Primary schoolchildren from Maputaland in northern KwaZulu-Natal were examined for Schistosoma haematobium infection, treated with praziquantel and re-examined four times over one year after treatment in order to assess the impact of treatment and patterns of infection and re-infection. RESULTS: Praziquantel treatment was highly efficacious at three weeks after treatment when judged by egg reduction rate (95.3%) and cure rate of heavy infections (94.1%). The apparent overall cure rate three weeks after treatment (57.9%) was much lower but improved to 80.7% at 41 weeks after treatment. Re-infection with S. haematobium was low and appeared to be limited to the hot and rainy summer. Analysis of only one urine specimen per child considerably underestimated prevalence when compared to the analysis of two specimens, but both approaches provided similar estimates of the proportion of heavy infections and of average infection intensity in the population. CONCLUSION: According to WHO guidelines the high prevalence and intensity of S. haematobium infection necessitate regular treatment of schoolchildren in the area. The seasonal transmission pattern together with the slow pace of re-infection suggest that one treatment per year, applied after the end of summer, is sufficient to keep S. haematobium infection in the area at low levels.

Patterns of geohelminth infection, impact of albendazole treatment and re-infection after treatment in schoolchildren from rural KwaZulu-Natal/South-Africa.

BACKGROUND: Geohelminth infection is a major health problem of children from rural areas of developing countries. In an attempt to reduce this burden, the Department of Health of the province of KwaZulu-Natal (KZN) established in 1998 a programme for helminth control that aimed at regularly treating primary school children for schistosomiasis and intestinal helminths. This article describes the baseline situation and the effect of treatment on geohelminth infection in a rural part of the province. METHODS: Grade 3 schoolchildren from Maputaland in northern KZN were examined for infections with hookworm, Ascaris lumbricoides, and Trichuris trichiura, treated twice with 400 mg albendazole and re-examined several times over one year after the first treatment in order to assess the impact of treatment and patterns of infection and re-infection. RESULTS: The hookworm prevalence in the study population (83.2%) was considerably higher than in other parts of the province whereas T. trichiura and especially A. lumbricoides prevalences (57.2 and 19.4%, respectively) were much lower than elsewhere on the KZN coastal plain. Single dose treatment with albendazole was very effective against hookworm and A. lumbricoides with cure rates (CR) of 78.8 and 96.4% and egg reduction rates (ERR) of 93.2 and 97.7%, respectively. It was exceptionally ineffective against T. trichiura (CR = 12.7%, ERR = 24.8%). Re-infection with hookworm and A. lumbricoides over 29 weeks after treatment was considerable but still well below pre-treatment levels. CONCLUSION: High geohelminth prevalences and re-infection rates in the study population confirm the need for regular treatment of primary school children in the area. The low effectiveness of single course albendazole treatment against T. trichiura infection however demands consideration of alternative treatment approaches.