Poovendhree Reddy

Detection and quantification of soil-transmitted helminths in environmental samples: A review of current state-of-the-art and future perspectives

It is estimated that over a billion people are infected with soil-transmitted helminths (STHs) globally with majority occurring in tropical and subtropical regions of the world. The roundworm (Ascaris lumbricoides), whipworm (Trichuris trichiura), and hookworms (Ancylostoma duodenale and Necator americanus) are the main species infecting people. These infections are mostly gained through exposure to faecally contaminated water, soil or contaminated food and with an increase in the risk of infections due to wastewater and sludge reuse in agriculture. Different methods have been developed for the detection and quantification of STHs eggs in environmental samples. However, there is a lack of a universally accepted technique which creates a challenge for comparative assessments of helminths egg concentrations both in different samples matrices as well as between locations. This review presents a comparison of reported methodologies for the detection of STHs eggs, an assessment of the relative performance of available detection methods and a discussion of new emerging techniques that could be applied for detection and quantification. It is based on a literature search using PubMed and Science Direct considering all geographical locations. Original research articles were selected based on their methodology and results sections. Methods reported in these articles were grouped into conventional, molecular and emerging techniques, the main steps in each method were then compared and discussed. The inclusion of a dissociation step aimed at detaching helminth eggs from particulate matter was found to improve the recovery of eggs. Additionally the selection and application of flotation solutions that take into account the relative densities of the eggs of different species of STHs also results in higher egg recovery. Generally the use of conventional methods was shown to be laborious and time consuming and prone to human error. The alternate use of nucleic acid-based techniques has improved the sensitivity of detection and made species specific identification possible. However, these nucleic acid based methods are expensive and less suitable in regions with limited resources and skill. The loop mediated isothermal amplification method shows promise for application in these settings due to its simplicity and use of basic equipment. In addition, the development of imaging soft-ware for the detection and quantification of STHs shows promise to further reduce human error associated with the analysis of environmental samples. It may be concluded that there is a need to comparatively assess the performance of different methods to determine their applicability in different settings as well as for use with different sample matrices (wastewater, sludge, compost, soil, vegetables etc.).

An evaluation of the knowledge, attitude and practices of South African university students regarding the use of emergency contraception and of art as an advocacy tool

Abstract Background: This study assessed the knowledge and use of emergency contraception (EC) against the background of current sexual practices among a multi-racial student population at the Durban University of Technology (DUT) in the province of KwaZulu-Natal, South Africa. In addition, the use of art as an advocacy tool in promoting awareness of EC and related sexual issues was also evaluated. Methods: A random sample of 162 students with equal representation of race and gender was interviewed. The questionnaire used addressed knowledge, attitudes and practices regarding contraception, with emphasis on EC and current sexual practices. It was administered by trained interviewers at three different sites at the DUT, where the Kara Walker image was also displayed on banners by Art for Humanity (AFH). Results: Over 77% of participants indicated that EC was some sort of birth control or contraceptive method. Only 51% of the respondents felt that EC was a good form of contraception and 27% of all students indicated that it should not be used at all. However, given a choice, 66% of African students would use it, compared to 46% Indian, 31% coloured and 52% white students. The various levels of undergraduate study (i.e. first to third year) did not impact on the level of knowledge of or attitude towards the use of EC among students. Students had health and social concerns, including that if more men were informed about EC, they may use it to pressure women into having unprotected sex. Over 90% of students knew that EC did not provide protection from HIV, AIDS and STDs. Of the 162 students questioned, only 21% had seen the Kara Walker poster and their responses to the banner were varied. While a few students thought that it was an inappropriate portrayal of women, most students who saw the banner thought it was effective in drawing attention to the consequences of unsafe sexual practices. Conclusion: It is imperative that concise information and pre- and post-counselling be provided by health care professionals to empower individuals at tertiary institutions to make informed choices with respect to reproductive health. Proper dissemination of information will create awareness and enhance wider acceptance and the use of the arts as an advocacy tool may further promote health education.

The impact of hygiene and localised treatment on the quality of drinking water in Masaka, Rwanda

The worldwide prevalence of waterborne diseases has been attributed to the lack of safe water, inadequate sanitation and hygiene. This study evaluated socio-demographic factors, microbiological quality of water at source and point of use (POU) at households, water handling and sanitation practices in a rural Rwandan community. Thirty five water samples from the source, Nyabarongo River, and water at point of use (POU) treated with the Slow Sand Filter (SSF) and Sûr’Eau methods, were analysed for total coliform and faecal coliform counts. Turbidity was measured in household samples. A structured questionnaire regarding water collection, storage, usage and waterborne disease awareness was administered to 324 women. Despite the significant reduction in coliforms and faecal coliforms from the Nyabarongo River following treatment using either SSF or Sûr’Eau, the water at point of use was found to be unsafe for human consumption. The frequency of diarrheal diseases were significantly higher among people who did not wash hands before food preparation (P = 0.002) and after using a toilet (P = 0.007) than among those who did. There was a statistically significant association between education levels and water treatment practices at the households (P < 0.05). Participants had limited knowledge regarding water storage practices for prevention of household water contamination. A combination of treatment methods with appropriate water handling should be considered. In addition, education is a fundamental precursor to advocating water treatment at POU.

Prenatal exposures and DNA methylation in newborns: a pilot study in Durban, South Africa

The in utero environment has the potential to influence epigenetic programming and subsequently the health of offspring. Even though pregnant women living in urban Africa are exposed to multiple chemicals and infectious agents that may impact their developing children, the neonatal epigenome has not been studied in these regions. We assessed whether prenatal exposures to air pollution and maternal human immunodeficiency virus (HIV) are associated with changes to DNA methylation throughout the epigenome using a pilot sample from the Mother and Child Environmental (MACE) birth cohort, of which 36% of the mothers are HIV positive. Families living in a high air pollution region (south Durban, n = 11) and a low air pollution region (north Durban, n = 11) with comparable socioeconomic characteristics were selected for analysis. DNA methylation was quantified in cord blood plasma DNA at >430 000 CpG sites using the Infinium HumanMethylation450 BeadChip. Sites associated with living in south Durban or maternal HIV infection (p < 0.001) were more likely to be hypomethylated and located in CpG islands. Top differentially methylated sites by region of Durban were enriched in pathways related to xenobiotic metabolism, oxygen and gas transport, and sensory perception of chemical stimuli when performing gene set enrichment testing with LRpath. Differentially methylated sites by maternal HIV status were enriched in cytochrome P450s, pathways involved in detection of chemical stimuli, metabolic processes, and viral regulation and processing. Given the small sample size of the study, future work examining the impact of prenatal exposures to air pollution, maternal infection, and antiviral treatment on the epigenome and downstream health implications is merited in Sub-Saharan African populations.

Concentration of soil-transmitted helminth eggs in sludge from South Africa and Senegal: A probabilistic estimation of infection risks associated with agricultural application

The use of sludge in agriculture has been encouraged as a means of increasing soil nutrient content and improving the water holding capacity. On the negative side, major public health concerns with sludge application prevail, mainly due to the high concentration of pathogenic microorganisms. Soil-transmitted helminths (STHs) are of major health concern in this regard, especially in endemic regions, mainly due to the high environmental resistant of the eggs combined with a low infectious dose. In this study the concentration of STH eggs in two months dried sludge from Durban, South Africa and Dakar, Senegal was determined and compared. Sampling was carried out from January to October 2016 and in September 2016 for Dakar. Ascaris spp, hookworm, Trichuris spp, Taenia spp and Toxocara spp were the commonly recorded STH eggs. STH egg concentrations were higher in Dakar than in Durban, with viable STH egg concentrations exceeding both local and international guidelines. Due to the high concentration of viable STH eggs, risks of Ascaris spp infection was very high for farmers applying this sludge on their farms in both Durban (7.9 × 10−1 (±1.7 × 10−2)) and Dakar (9.9 × 10−1 (±1.3 × 10−5)). Consumption of lettuce grown on sludge amended soil will result in probable infections but harvest after 30 days between sludge application and harvest in Durban gave median probability infection risks with a risk level similar to the WHO tolerable risk value (10−4). This time period need to be prolonged to harvest in Dakar to 40 days to reduce the risks of infection to the tolerable risks values. Further treatment of the sludge either through composting or drying for longer periods of time is thus recommended from a public health perspective.

Methods for the detection of Cryptosporidium and Giardia: From microscopy to nucleic acid based tools in clinical and environmental regimes

The detection and characterization of genotypes and sub genotypes of Cryptosporidium and Giardia is essential for their enumeration, surveillance, prevention, and control. Different diagnostic methods are available for the analysis of Cryptosporidium and Giardia including conventional phenotypic tools that face major limitations in the specific diagnosis of these protozoan parasites. The substantial advancement in the development of genetic signature based molecular tools for the quantification, diagnosis and genetic variation analysis has increased the understanding of the epidemiology and preventive measures of related infections. The conventional methods such as microscopy, antibody and enzyme based approaches, offer better detection results when combined with advanced molecular methods. Gene based approaches increase the precision of identification, for example, many signatures detected in environmental matrices represent species/genotype that are not infectious to humans. This review summarizes the available methods and the advantages and limitations of advance detection techniques like nucleic acid-based approaches for the detection of viable oocysts and cysts of Cryptosporidium and Giardia along with the conventional and widely accepted detection techniques like microscopy, antibody and enzyme based ones. This technical article also encourages the wide application of molecular methods in genetic characterization of distinct species of Cryptosporidium and Giardia, to adopt necessary preventive measures with reliable identification and mapping the source of contamination.

Interaction between ambient pollutant exposure, CD14 (-159) polymorphism and respiratory outcomes among children in Kwazulu-Natal, Durban

The objective of this study was to determine if the association between exposure to ambient air pollutants such as sulfur dioxide, nitrogen dioxde (NO2), nitrous oxide (NO), and PM10, and variation in lung function measures was modified by genotype. A validated questionnaire was administered to 71 African children to evaluate prevalence of respiratory symptoms. Atopy was evaluated by skin-prick testing and bihourly measures of lung function (spirometry) were collected. Gaseous air pollutant concentrations were monitored continuously. CD14 polymorphism was genotyped and plasma CD14 levels were measured. There was no statistically significant association between the CD14 (159) CT+TT polymorphism with any asthma-related phenotype. There was a significant association between lung function (forced expiratory volume in 1 second intraday variability) and NO2 and NO among participants carrying the CD14 CT/TT genotype for lags 1, 2, and the 5-day average. Similarly, statistically significant gene–pollutant interactions (p < 0.05) were found with NO and CD14 CT/TT at lag 2 and for the 5-day average. While there was no association with any respiratory phenotype (as determined by symptoms), the CD14 CT/TT genotype appeared to be protective to increased exposure to NO2 and NO.

Effect of reagents used during detection and quantification of Ascaris suum in environmental samples on egg viability

Soil-transmitted helminths (STHs) are a major health concern globally. Infection is mostly through contact with contaminated water, food or soil. Therefore to break the cycle of viable transmission STH eggs must be quantitatively detected in the environment. The effect of different reagents on the viability of Ascaris suum eggs during laboratory detection and quantification was assessed and different incubation solutions compared. Sulphuric acid gave a slightly higher recovery percentage of viable eggs (91.2%) than distilled water (90.0%) and 0.5% formalin (87.6%), although the difference was not statistically significant (p > 0.05). Acetoacetic acid, ethyl acetate, ammonium bicarbonate, zinc sulphate, magnesium sulphate and Tween 80, are reagents widely used in test protocols for the detection and quantification of STH eggs. Eggs were exposed to these reagents for different time durations. Acetoacetic acid resulted in the highest loss of viability (3.4 ± 0.7% viable), while magnesium sulphate resulted in the least effect (88.5 ± 1.2% viable). In conclusion the use of the selected reagents in the detection of these eggs was found to affect the viability of exposed eggs, especially during prolonged exposures. Therefore we recommended that eggs be exposed for ≤5 minutes, to reduce the risk of viability loss.

Obstetric outcomes and antenatal access among adolescent pregnancies in Kwazulu-Natal, South Africa

Background: Pregnancy among adolescents in South Africa is a growing concern as it may be associated with adverse socio-economic and health impacts. Timeous initiation and optimal utilisation of antenatal care (ANC) services is imperative to ensure positive pregnancy outcomes. However, this is not always possible owing to various challenges. Methods: A multi-method study design using both retrospective record review and qualitative interviews was undertaken at a district hospital on the North Coast of KwaZulu-Natal, South Africa. Data on ANC attendance trends and obstetric/perinatal outcomes for all recorded adolescent pregnancies (13–16 years) at the district hospital under study was collected over 3 years (2011–2013) (n = 314). Qualitative interviews with randomly selected pregnant adolescents were conducted to assess experiences of ANC access and utilisation. Results: Late ANC booking and reduced ANC visits were common for adolescent pregnancies. Under-utilisation of ANC (i.e. less than 4 visits) was significantly associated with lower gestational age (< 37 weeks) (OR = 2.64; 95% CI = 1.04; 6.74; p < 0.05). Low birthweight, low Apgar scores as well as the incidence of maternal anaemia and pregnancy-induced hypertension (PIH) were found to be related to late ANC booking. In-depth interviews suggested that teenagers suffered emotional vulnerability linked to family, partner and financial support. They discussed various barriers linked with accessing ANC while acknowledging perceived benefits. Conclusion: Adolescent pregnancy was associated with late booking and reduced ANC visits, which was a risk for adverse maternal health outcomes. In-depth interviews suggested numerous challenges associated with ANC access including; financial barriers, attitude of healthcare workers (HCWs), long queues, distance travelled to access ANC services, human immunodeficiency virus (HIV) status and a lack of knowledge.

Factors associated with unintended pregnancy among women attending a public health facility in KwaZulu-Natal, South Africa

Abstract Background: Across the globe a large proportion of pregnancies have been reported as unintended. There are no available reports from South Africa concerning the prevalence of unintended pregnancies. This study explored the prevalence of unintended pregnancies among South African women attending a public primary health care (PHC) clinic in KwaZulu-Natal (KZN), South Africa. It also investigated the relationship between demographic factors, contraceptive use, substance abuse and unintended pregnancy in this setting. Methods: A descriptive cross-sectional survey was conducted among patients (n = 328) attending a PHC clinic. Participants were recruited by convenience sampling. Women who attended the clinic on their first antenatal visit were invited to participate. Participants filled out questionnaires in either English or isiZulu. Association between pregnancy and categorical variables was assessed. Results: Participants were mostly single (89.9%; n = 267), unemployed (70.8%; n = 222) with a monthly income of less than R 1 500 per month (63.8%; n = 81). Two-thirds of the women (64.33%; n = 211) had unintended pregnancies. There was a significant relationship between marital status and unintended pregnancy. Women who were married or living with their partners were more likely to have planned their pregnancies as compared with those who were single or divorced. Unemployed women were more likely to have had unintended pregnancies. No other socio-demographic factors were linked to unintended pregnancy. Conclusion: It is concluded that in this population of South African women with low education levels and low income, the prevalence of unintended pregnancies is high. These unintended pregnancies are linked to single status as well as unemployment.