Search

Background Sapovirus is one of the principal agents of acute viral enteritis in children. Because it has not been routinely included in diagnostic evaluations, the epidemiology and natural history remain poorly described. Methods A birth cohort of 1715 children from 8 countries contributed surveillance samples (n = 35 620) and diarrheal specimens (n = 6868) from 0 to 24 months of age. Sapovirus was detected by quantitative polymerase chain reaction concurrently to other enteropathogens using multiarray cards. Logistic regression was used to identify risk factors, and longitudinal models were employed to estimate incidence rates and evaluate evidence of protective immunity. Results Sapovirus was detected in 24.7% (n = 1665) of diarrheal stools and 12.8% (n = 4429) of monthly surveillance samples. More than 90% of children were infected and 60% experienced sapovirus diarrhea in the first 2 years of life. Breastfeeding and higher socioeconomic status were associated with reduced incidence of infection and illness. Specimens with sapovirus detected had an increased odds of coinfection with rotavirus (odds ratio [OR], 1.6 [95% confidence interval {CI}, 1.3–2.0]), astrovirus (OR, 1.5 [95% CI, 1.3–1.7]), adenovirus (OR, 1.3 [95% CI, 1.1–1.5]), and Shigella (OR, 1.4 [95% CI, 1.3–1.6]). Prior infection with sapovirus conferred a risk reduction of 22% for subsequent infection (hazard ratio [HR], 0.78 [95% CI, .74–.85]) and 24% for subsequent diarrhea (95% CI, 11.0%–35.0%; HR, 0.76). Conclusions Sapovirus is a common cause of early childhood diarrhea. Further research on coinfections is warranted. Evidence of acquired immunity was observed even in the absence of genotype-specific analysis for this pathogen of known genetic diversity.

Background. With the recent increase in antibiotic resistance to conventional antibiotics, gold nanoparticles, and medicinal plants, extracts present an interesting alternative. Objectives. This study aimed to synthesize, characterize, and evaluate Pyrenacantha grandiflora Baill extracts and gold nanoparticle conjugates against pathogenic bacteria. Methods. We synthesized gold nanoparticles by chemical and biological methods. The nanoparticles were characterized by the use of UV-visible spectrophotometry, followed by transmission electron microscopy (TEM) and energy-dispersive X-ray analysis (EDX). Gold nanoparticles were conjugated to plant extracts and analyzed with a Fourier-transform infrared spectroscope (FTIR). We determined the antimicrobial activity of the conjugates using well diffusion and the microdilution assays. Results. The UV–visible spectra of gold nanoparticles showed a synthesis peak at 530 nm. FTIR analysis indicated functional biomolecules that were associated with plant extract conjugated gold nanoparticles; the formation of C–H group and carbonyl (C=O) groups, –OH carbonyl, and C≡C groups were also observed. Biologically synthesized nanoparticles were star-shaped when observed by TEM with an average size of 11 nm. Gold nanoparticles synthesized with P. grandiflora water extracts showed the largest zone of inhibition (22 mm). When the gold nanoparticles synthesized by the biological method were conjugated with acetone extracts of P. grandiflora, MIC as low as 0.0063 mg/mL was observed against beta-lactamase producing K. pneumonia. The activity of acetone extracts was improved with chemically synthesized gold nanoparticles particularly when beta-lactamase producing E. coli and MRSA were used as test organisms. A synergistic effect was observed against all tested bacteria, except for MRSA when gold nanoparticles were conjugated with acetone extract. Conclusion. Overall, P. grandiflora tuber extracts conjugated with gold nanoparticles showed a very good antibacterial activity that improved both plant extract and gold nanoparticle’s individual activity.

Background The application of molecular diagnostics has identified enteric group adenovirus serotypes 40 and 41 as important causes of diarrhea in children. However, many aspects of the epidemiology of adenovirus 40/41 diarrhea have not been described. Methods We used data from the 8-site Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development Project birth cohort study to describe site- and age-specific incidence, risk factors, clinical characteristics, and seasonality. Results The incidence of adenovirus 40/41 diarrhea was substantially higher by quantitative polymerase chain reaction than enzyme immunoassay and peaked at ∼30 episodes per 100 child-years in children aged 7–15 months, with substantial variation in incidence between sites. A significant burden was also seen in children 0–6 months of age, higher than other viral etiologies with the exception of rotavirus. Children with adenovirus 40/41 diarrhea were more likely to have a fever than children with norovirus, sapovirus, and astrovirus (adjusted odds ratio [aOR], 1.62; 95% CI, 1.16–2.26) but less likely than children with rotavirus (aOR, 0.66; 95% CI, 0.49–0.91). Exclusive breastfeeding was strongly protective against adenovirus 40/41 diarrhea (hazard ratio, 0.64; 95% CI, 0.48–0.85), but no other risk factors were identified. The seasonality of adenovirus 40/41 diarrhea varied substantially between sites and did not have clear associations with seasonal variations in temperature or rainfall. Conclusions This study supports the situation of adenovirus 40/41 as a pathogen of substantial importance, especially in infants. Fever was a distinguishing characteristic in comparison to other nonrotavirus viral etiologies, and promotion of exclusive breastfeeding may reduce the high observed burden in the first 6 months of life.

Background Prolonged enteropathogen shedding after diarrhea complicates the identification of etiology in subsequent episodes and is an important driver of pathogen transmission. A standardized approach has not been applied to estimate the duration of shedding for a wide range of pathogens. Methods We used a multisite birth cohort of children 0–24 months of age from whom diarrheal and monthly nondiarrheal stools were previously tested by quantitative polymerase chain reaction for 29 enteropathogens. We modeled the probability of detection of the etiologic pathogen before and after diarrhea using a log-normal accelerated failure time survival model and estimated the median duration of pathogen carriage as well as differences in subclinical pathogen carriage 60 days after diarrhea onset in comparison to a prediarrhea baseline. Results We analyzed 3247 etiologic episodes of diarrhea for the 9 pathogens with the highest attributable burdens of diarrhea. The median duration of postdiarrheal carriage varied widely by pathogen, from about 1 week for rotavirus (median, 8.1 days [95% confidence interval {CI}, 6.2–9.6]) to >1 month for Cryptosporidium (39.5 days [95% CI, 30.6–49.0]). The largest increases in subclinical pathogen carriage before and after diarrhea were seen for Cryptosporidium (prevalence difference between 30 days prior and 60 days after diarrhea onset, 0.30 [95% CI, .23–.39]) and Shigella (prevalence difference, 0.21 [95% CI, .16–.27]). Conclusions Postdiarrheal shedding was widely variable between pathogens, with strikingly prolonged shedding seen for Cryptosporidium and Shigella. Targeted antimicrobial therapy and vaccination for these pathogens may have a relatively large impact on transmission., In a multisite birth cohort study of children 0–24 months of age and with quantitative polymerase chain reaction detection of diarrheal pathogens, we estimate the duration of postdiarrheal carriage in low-resource settings, with strikingly prolonged shedding seen for Cryptosporidium and Shigella.

Enteric infections early in life have been associated with poor linear growth among children in low-resource settings. Point-of-use water treatment technologies provide effective and low-cost solutions to reduce exposure to enteropathogens from drinking water, but it is unknown whether the use of these technologies translates to improvements in child growth. We conducted a community-based randomized controlled trial of two water treatment technologies to estimate their effects on child growth in Limpopo, South Africa. We randomized 404 households with a child younger than 3 years to receive a silver-impregnated ceramic water filter, a silver-impregnated ceramic tablet, a safe-storage water container alone, or no intervention, and these households were followed up quarterly for 2 years. We estimated the effects of the interventions on linear and ponderal growth, enteric infections assessed by quantitative molecular diagnostics, and diarrhea prevalence. The silver-impregnated ceramic water filters and tablets consistently achieved approximately 1.2 and 3 log reductions, respectively, in total coliform bacteria in drinking water samples. However, the filters and tablets were not associated with differences in height (height-for-age z-score differences compared with no intervention: 0.06, 95% CI: −0.29, 0.40, and 0.00, 95% CI: −0.35, 0.35, respectively). There were also no effects of the interventions on weight, diarrhea prevalence, or enteric infections. Despite their effectiveness in treating drinking water, the use of the silver-impregnated ceramic water filters and tablets did not reduce enteric infections or improve child growth. More transformative water, sanitation, and hygiene interventions that better prevent enteric infections are likely needed to improve long-term child growth outcomes.

Background and objective Recently, there has been evidence for the accumulation of steroid hormones in the water environment with negative consequences on fish and humans. However, there is paucity of information on how the steroid hormones influence the microbial community in environmental waters. The objective of this study was to determine the occurrence of 17β-estradiol (E2) and its potential influence on the diversity of Aeromonas spp. Materials and methods Wastewater samples were obtained from sewage treatment plants in northern South Africa and fish samples were collected from the Nandoni dam. Aeromonas spp. were isolated using microbiological methods and PCR protocols were used for their identification. A commercial Elisa kit was used for measuring the concentration of 17β-estradiol (E2) from the wastewater samples as well as the fish samples. Results 17β-estradiol (E2) was found in high concentration in sewage samples varying from 0.32-348.6 pg mL-1 while in fish samples, it ranged from 1.1-73.6 pg mL-1. There was a tendency of samples with high E2 concentrations to have higher diversity of Aeromonas spp., implying that steroid hormones may serve as nutrient for Aeromonas spp. Aeromonas hydrophila was the most prevalent species (71%), followed by A. sobria with (68%). Conclusion The presence of Aeromonas spp. in environmental waters and fish that is consumed by the local community poses a serious health concern. The high content of E2 in treated wastewater is of serious concern as well. For the first time, the present study showed a positive impact of E2 on Aeromonas growth.

Background The degree of protection conferred by natural immunity is unknown for many enteropathogens, but it is important to support the development of enteric vaccines. Methods We used the Andersen-Gill extension of the Cox model to estimate the effects of previous infections on the incidence of subsequent subclinical infections and diarrhea in children under 2 using quantitative molecular diagnostics in the MAL-ED cohort. We used cross-pathogen negative control associations to correct bias due to confounding by unmeasured heterogeneity of exposure and susceptibility. Results Prior rotavirus infection was associated with a 50% lower hazard (calibrated hazard ratio [cHR], 0.50; 95% confidence interval [CI], 0.41–0.62) of subsequent rotavirus diarrhea. Strong protection was evident against Cryptosporidium diarrhea (cHR, 0.32; 95% CI, 0.20–0.51). There was also protection due to prior infections for norovirus GII (cHR against diarrhea, 0.67; 95% CI, 0.49–0.91), astrovirus (cHR, 0.62; 95% CI, 0.48–0.81), and Shigella (cHR, 0.79; 95% CI, 0.65–0.95). Minimal protection was observed for other bacteria, adenovirus 40/41, and sapovirus. Conclusions Natural immunity was generally stronger for the enteric viruses than bacteria, potentially due to less antigenic diversity. Vaccines against major causes of diarrhea may be feasible but likely need to be more immunogenic than natural infection., We estimated natural immunity to enteric pathogens as the effects of previous infections on the incidence of subsequent infections in children under 2. Prior rotavirus, Cryptosporidium, norovirus GII, astrovirus, and Shigella infections were associated with lower risk of subsequent diarrhea.

An innovative and sustainable approach to integrating modified Ag–MgO–nanohydroxyapatite on a nanofibrous cellulose template (CNF-AgMgOnHaP) as a multifunctional adsorbent via a hydrothermal bioreduction route using Citrus paradisi peel extract was developed and examined. The surface morphology and mineralogical properties of CNF-AgMgOnHaP by UV–vis spectroscopy, SEM-EDS, XRD, FTIR, TEM, and BET techniques are reported. Batch fluoride sorption studies and its disinfection potential against common bacteria in surface water were evaluated. The results showed the successful synthesis of a modified multistructural CNF-AgMgOnHaP composite with an improved BET surface area of 160.17 m2/g. The sorption of fluoride by the adsorbent was found to strongly depend on the different sorption conditions with a maximum F− sorption capacity of 8.71 mg/g at 303 K, and pH of 5 with 0.25 g dosage at 10 min contact time (25 ± 3 °C). Equilibrium fluoride sorption onto the CNF-AgMgOnHaP was best described by the Freundlich isotherm model across all the operating temperatures. The overall kinetic results showed that the adsorption mechanisms not only depend on using the pseudo-second-order process but are also governed by the mass transfer of the adsorbate molecules from the external surface onto the pores of the adsorbent. The thermodynamic parameters revealed that the adsorption process of F− onto CNF-AgMgOnHaP was endothermic and spontaneous at the sorbent/solution interface. The synthesized composite also provides some antibacterial activity against common infectious microbes from contaminated drinking water. The overall results suggested that the CNF-AgMgOnHaP nanocomposite possesses the potential for the simultaneous decontamination of pollutants and microbes in drinking water.

BACKGROUND: Even though E. histolytica is recognized as an effective pathogen, what determines the outcome of this infection is still not well understood. The present study was carried out to determine the genetic characteristics of E. histolytica isolates from two different regions in South Africa. METHOD: Diarrheal and non-diarrheal stool samples were collected from patients of all ages from Giyani and Pretoria. Different PCR protocols were used to identify E. histolytica and amplify the serine rich E. histolytica protein (SREHP) and chitinase genes. The profiles obtained were compared among the different samples.RESULTS: Out of 111 stool samples collected, 51 were positive by either PCR or microscopy and 14 samples were positive by both methods. The serine- rich E. histolytica protein was amplified in 26 samples. Out of the 26 samples (19) different SREHP profiles were obtained. SREHP #2 was obtained in 5 different samples, 4 from Pretoria and 1 from Giyani (2 diarrheal and 3 non-diarrheal). The chitinase gene was amplified from 51 samples and 22 different chitinase profiles were obtained. Of all the profiles, profile #4 was found in 6 different isolates, 5 from Giyani and 1 from Pretoria (3 symptomatic and 3 asymptomatic). However, profile # 18 was only found in formed stools from Giyani. CONCLUSIONS. The results obtained in this study have further confirmed the genetic heterogeneity of E. histolytica for the SREHP and chitinase genes which might have a significant influence in the outcome of amebic infection, depending on the genetic profile of the infecting strain.

In this study, we report on the prevalence of 19 virulence genes in enteroaggregative Escherichia coli (EAEC) isolates from northern South Africa. Stool samples obtained prospectively from 97 children from 1 to 12 months of age were analyzed, and EAEC isolates were confirmed based on the presence of aaiC or aatA genes. We investigated 177 enteroaggregative Escherichia coli isolates for the prevalence of virulence genes using multiplex polymerase chain reaction. The chromosomal gene aaiC was detected at higher frequency (48.0%) compared with aatA (26.0%). The gene encoding the open reading frame Orf61 was the most prevalent putative virulence trait detected among the isolates (150/177; 84.7%). None of the genes was statistically associated with diarrhea (P > 0.05). Detection rates were higher during 7-12 month of life with an association observed for the pic gene and the age group 7-12 months (P = 0.04). Winter was the season with the highest detection rates. Our data reveal a high prevalence of Orf61, Orf3, and astA in South African EAEC isolates. Specific genes may provide additional markers for the study of disease associations with age and season of sample collection.

Campylobacter species infections have been associated with malnutrition and intestinal inflammation among children in low-resource settings. However, it remains unclear whether that association is specific to Campylobacter jejuni/coli. The aim of this study was to assess the association between both all Campylobacter species infections and Campylobacter jejuni/coli infections on growth and enteric inflammation in children aged 1–24 months. We analyzed data from 1715 children followed from birth until 24 months of age in the MAL-ED birth cohort study, including detection of Campylobacter species by enzyme immunoassay and Campylobacter jejuni/coli by quantitative PCR in stool samples. Myeloperoxidase (MPO) concentration in stool, used as a quantitative index of enteric inflammation, was measured. The incidence rate per 100 child-months of infections with Campylobacter jejuni/coli and Campylobacter species during 1–24 month follow up were 17.7 and 29.6 respectively. Female sex of child, shorter duration of exclusive breastfeeding, lower maternal age, mother having less than 3 living children, maternal educational level of Campylobacter jejuni/coli infection. The cumulative burden of both Campylobacter jejuni/coli infections and Campylobacter species were associated with poor growth and increased intestinal inflammation.

Background Environmental enteric dysfunction (EED) is thought to increase the risk of micronutrient deficiencies, but few studies adjust for dietary intakes and systemic inflammation. Objective We tested whether EED is associated with micronutrient deficiency risk independent of diet and systemic inflammation, and whether it mediates the relation between intake and micronutrient status. Methods Using data from 1283 children in the MAL-ED (Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health) birth cohort we evaluated the risk of anemia, low retinol, zinc, and ferritin, and high transferrin receptor (TfR) at 15 mo. We characterized gut inflammation and permeability by myeloperoxidase (MPO), neopterin (NEO), and α-1-antitrypsin (AAT) concentrations from asymptomatic fecal samples averaged from 9 to 15 mo, and averaged the lactulose:mannitol ratio z-score (LMZ) at 9 and 15 mo. Nutrient intakes from complementary foods were quantified monthly from 9 to 15 mo and densities were averaged for analyses. α-1-Acid glycoprotein at 15 mo characterized systemic inflammation. Relations between variables were modeled using a Bayesian network. Results A greater risk of anemia was associated with LMZ [1.15 (95% CI: 1.01, 1.31)] and MPO [1.16 (1.01, 1.34)]. A greater risk of low ferritin was associated with AAT [1.19 (1.03, 1.37)] and NEO [1.22 (1.04, 1.44)]. A greater risk of low retinol was associated with LMZ [1.24 (1.08, 1.45)]. However, MPO was associated with a lower risk of high transferrin receptor [0.86 (0.74, 0.98)], NEO with a lower risk of low retinol [0.75 (0.62, 0.89)], and AAT with a lower risk of low plasma zinc [0.83 (0.70, 0.99)]. Greater nutrient intake densities (vitamins A and B6, calcium, protein, and zinc) were negatively associated with EED. Inverse associations between nutrient densities and micronutrient deficiency largely disappeared after adjustment for EED, suggesting that EED mediates these associations. Conclusions EED is independently associated with an increased risk of low ferritin, low retinol, and anemia. Greater nutrient density from complementary foods may reduce EED, and the control of micronutrient deficiencies may require control of EED.

This study focuses on time-dependent microwave-assisted biosynthesis of silver nanoparticles using aqueous peel extracts of Citrus paradisi as a reducing, stabilizing and capping agent with emphasis on its antibacterial property. Optical, structural and morphological properties of the synthesized Citrus paradisi peel extract silver nanoparticle (CPAgNp) were characterized using UV-visible spectrophotometer, transmission electron microscope (TEM), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), Brunauer–Emmett–Teller (BET) and X-ray diffractometer (XRD). The antimicrobial activity was evaluated using the well- and disc-diffusion methods. Characteristic surface plasmon resonance (SPR) wavelength in the range of 420–440 nm at an optimized intensity growth rate typical of silver nanoparticles was obtained. The synthesized CPAgNp are spherical in shape having the size range of 14.84 ± 5 nm and possessing fcc unit phase structure. The Citrus paradisi peel extract mediated AgNp were found to possess a broad-spectrum antimicrobial activity against water-borne pathogenic microbes.

Ethnobotanical relevance Invasive alien plant species are used individually or in combinations to treat sexually transmitted infections (STI's). However, ethnobotanical information of invasive alien species is scanty, especially on the treatment of STI's. The aim of the study Document ethnobotanical applications of invasive alien species in the treatment of STI's in the Waterberg District of Limpopo Province, South Africa. Materials and methods An ethnobotanical survey was conducted in the Waterberg District. Using a semi-structured questionnaire, 30 traditional health practitioners were selected via snowball sampling. Importance of medicinal plants was analysed using Fidelity Level (FL), Informant Consensus Factor (ICF), and the Use Value (UV). Results Fourteen invasive alien species belonging to ten families were documented for the treatment of seven STI's. Plant species were mostly utilised for their roots (58.8%) and leaves (23.6%). Up to 60% of the species were used individually, while combination therapy was also common (40%). A decoction was the preferred method of preparation. The administration mode was predominantly oral (92.7%). Important species with high FL and with high use-report were Opuntia ficus-indica (63.9) and Catharantheus roseus (57.3). The highest ICF values were cited for mokabe (testicular swelling) (1) and gonorrhoea (0.73), with Senna didymobotrya and C. roseus being the most frequently used species. Species with the highest UV values were C. roseus (0.65), Agave sisalana (0.41) and Solanum elaegnifolium (0.55). Conclusion Agave sisalana, Catharanthus roseus, Opuntia ficus-indica, Ricinus communis, Senna didymobotrya, and solanum species were the most commonly used species for the treatment of sexually transmitted infections in the Waterberg District. Further pharmacological studies are encouraged on the species with the highest FL, ICF and UV values.

Presence of fluoride and pathogen in drinking water is an issue of concern due to their health effects and as such much effort is being directed towards finding sustainable material for use in water treatment. Adsorption based water treatment techniques are often considered as the most effective and easy to use in rural set up. However, most of the adsorbents are not multifunction and are only effective towards fluoride. In this study aluminosilicate activated clay was hydrothermally treated and applied for fluoride and pathogen removal from water. Fourier transform infrared (FTIR), Brunauer-Emmett-Teller method (BET), X-ray diffraction spectroscopy (XRD) and Scanning electron microscopy-energy dispersion spectroscopy (SEM-EDS) techniques were employed to characterize hydrothermally treated aluminosilicate clay (HTAC). Batch defluoridation experiments were used to evaluate the fluoride removal efficiency while well diffusion assay method was used to evaluate the antimicrobial efficiency. The BET results showed increase in surface area from 17.19 m2/g to 33.56 m2/g after treatment. Batch defluoridation showed maximum adsorption capacity of 1.75 mg/g with 53% fluoride removal from initial fluoride concentration of 6 mg/L using 0.8 g/40 mL dosage at initial pH 5.8 and contact time of 5 min at room temperature. The adsorption kinetics data showed a better fit to pseudo-second order model while the adsorption isotherm data showed correlation coefficient and chi-square values of 0.98 and 0.01, respectively indicating a better fit to both Langmuir and Freundlich adsorption isotherms. The regeneration studies showed that the material can be reused for up to six times using 0.1 M KCl as regenerant. Antimicrobial studies showed that HTAC has potency against Escherichia coli (E. coli) strains. The study showed that synthesized HTAC has strong potential for application in fluoride and pathogen removal.

Dengue virus (DENV) causes a spectrum of diseases ranging from asymptomatic, mild febrile to a life-threatening illness: dengue hemorrhagic fever. The main clinical symptom of dengue is fever, similar to that of malaria. The prevalence of dengue virus infection, alone or in association with other endemic infectious diseases in children in Cameroon is unknown. The aim of this study was to determine the prevalence of dengue, malaria and HIV in children presenting with fever and associated risk factors. Dengue overall prevalence was 20.2%, Malaria cases were 52.7% and HIV cases represented 12.6%. The prevalence of dengue-HIV co-infection was 6.0% and that of Malaria-dengue co-infection was 19.5%. Triple infection prevalence was 4.3%. Dengue virus infection is present in children and HIV-Dengue or Dengue- Malaria co-infections are common. Dengue peak prevalence was between August and October. Sex and age were not associated with dengue and dengue co-infections. However, malaria as well as HIV were significantly associated with dengue (P = 0.001 and 0.028 respectively). The diagnosis of dengue and Malaria should be carried out routinely for better management of fever., Author summary Fever is a symptom common to several infectious diseases such as malaria, yellow fever, dengue fever and typhoid which are all present in Cameroon. In most cases, fever in Cameroon is assumed to be due to malaria and treated as such. This study present the prevalence of dengue fever among febrile children. Dengue fever as well as malaria is common among Cameroonian children. Since Cameroon is endemic for malaria, fever may indicate either malaria or dengue. Clinicians should be aware of the presence of dengue in Cameroon. Knowing the risk factors, parents are encouraged to use the bed net to protect their children and clean stagnant water from their environment. Children could be co-infected by dengue, malaria as well as HIV. Management of patients with dengue fever and HIV infection should be studied, especially in infants where both viral diseases are more severe. Close monitoring may prevent complications among HIV-infected individuals who contract dengue fever.

Background: Our understanding of the disease caused by the various Entamoeba species and its epidemiology is changing with time, and very little is known about their genetic diversity. Therefore, this study sought to investigate the prevalence and genetic diversity of Entamoeba species among children under 5 years in the Vhembe District, South Africa.Methods: A total of 534 stool samples from 313 children (both males and females) aged under 5 were collected from 12 villages in Vhembe District, Limpopo. The prevalence of Entamoeba infections was examined by microscope and PCR, followed by Sanger sequencing for specific regions of 18S rRNA gene to identify and differentiate the circulating species of Entamoeba in the study population. Results: Of the 313 children recruited in the study, 163 were females and 150 were males, the ages ranged from 1 to 3 years. Of the 534 samples, 130/534 (24.3%) were microscopically positive for Entamoeba cysts. However, Entamoeba genus-specific DNA amplification using PCR identified 43/534 (8%) of Entamoeba species. Twenty positive amplicons were sequenced by Sanger sequencing technologies. Out of the twenty samples, twelve (60%) were confirmed to be Entamoeba species. The Entamoeba species identified in the study as evidenced by BLAST calls in the NCBI database and phylogenetic tree after narrowing the search using the option Entamoeba taxid (5758) from the NCBI database included 4 E. polecki (33.3%), 6 E. coli (50%), one E. muris (8.3%) and one E. hartmanni (8.3%). The phylogenetic tree showed the close relationship between isolated species and the ones in the GenBank.Conclusion: The current study has shown for the first time the presence of E. polecki in humans and the existence of possibly two types of E. coli infecting humans. Our findings further emphasize the need for the re-evaluation of the pathogenicity of species such as E. polecki which are quite common in the study population and might be responsible for some of the health complications.

Culture-independent diagnostics have revealed a larger burden of Shigella among children in low-resource settings than previously recognized. We further characterized the epidemiology of Shigella in the first two years of life in a multisite birth cohort. We tested 41,405 diarrheal and monthly non-diarrheal stools from 1,715 children for Shigella by quantitative PCR. To assess risk factors, clinical factors related to age and culture positivity, and associations with inflammatory biomarkers, we used log-binomial regression with generalized estimating equations. The prevalence of Shigella varied from 4.9%-17.8% in non-diarrheal stools across sites, and the incidence of Shigella-attributable diarrhea was 31.8 cases (95% CI: 29.6, 34.2) per 100 child-years. The sensitivity of culture compared to qPCR was 6.6% and increased to 27.8% in Shigella-attributable dysentery. Shigella diarrhea episodes were more likely to be severe and less likely to be culture positive in younger children. Older age (RR: 1.75, 95% CI: 1.70, 1.81 per 6-month increase in age), unimproved sanitation (RR: 1.15, 95% CI: 1.03, 1.29), low maternal education (, Author summary Shigella is the second leading cause of diarrhea morbidity and mortality among children in low and middle-income countries. We characterized the epidemiology of Shigella using highly sensitive diagnostic methods in 41,405 diarrheal and monthly non-diarrheal stools from the first two years of life in a multisite birth cohort. The prevalence of Shigella varied from 4.9%-17.8% across sites, and the incidence of Shigella-attributable diarrhea was 31.8 cases (95% CI: 29.6, 34.2) per 100 child-years. Shigella diarrhea episodes were more likely to be severe and less likely to be culture positive in younger children. Older age, unimproved sanitation, low maternal education, initiating complementary foods before 3 months, and malnutrition were risk factors for Shigella. There was a linear dose-response between Shigella quantity and myeloperoxidase, a marker of intestinal inflammation, which suggests a potential mechanism for the impact of Shigella on child growth. Because culture missed most clinically relevant cases of severe diarrhea and dysentery, molecular diagnostics may be important tools in upcoming Shigella vaccine trials.

Enteric infections and water-related illnesses are more frequent during times of relative water abundance, especially in regions that experience bimodal rainfall patterns. However, it is unclear how seasonal changes in water availability and drinking water source types affect enteric infections in young children. This study investigated seasonal shifts in primary drinking water source type and the effect of water source type on enteric pathogen prevalence in stool samples from 404 children below age 5 in rural communities in Limpopo Province, South Africa. From wet to dry season, 4.6% (n = 16) of households switched from a source with a higher risk of contamination to a source with lower risk, with the majority switching to municipal water during the dry season. In contrast, 2.6% (n = 9) of households switched from a source with a lower risk of contamination to a source with higher risk. 74.5% (n = 301) of the total households experienced interruptions in their water supply, regardless of source type. There were no significant differences in enteric pathogen prevalence between drinking water sources. Intermittent municipal water distribution and household water use and storage practices may have a larger impact on enteric infections than water source type. The limited differences in enteric pathogen prevalence in children by water source could also be due to other exposure pathways in addition to drinking water, for example through direct contact and food-borne transmission.

Introduction: Human microsporidiosis represents an important and rapidly emerging opportunistic disease. The present study investigated the prevalence of microsporidia among HIV positive and HIV negative patients with or without diarrhoea in Vhembe and Mopani Districts in the Limpopo Province. Methodology: A total of 170 stool samples were collected from these patients and microsporidia species was detected using a Real-Time PCR targeting a conserved region of the small ribosomal subunit rRNA (SSU-rRNA) gene of Enterocytozoon bieneusi, Encephalitozoon intestinalis, Encephalitozoon hellem, and Encephalitozoon cuniculi. Results: Fifty six (32.9%) were positive for microsporidia. The prevalence was higher in HIV negative patients (36.6%) while 24.1% of patients who were HIV positive had microsporidia. Microsporidia was more common among patients aged between 1 and 10 years (52.6%). However among the HIV positive patients, microsporidia prevalence was higher among those that were not taking antiretrovirals (ARVs) compared to those who were on ARVs, (36.6%) and (24.1%), respectively. Microsporidia was also noted to be significantly associated with diarrheal and stomach pains; p = 0.02 and p = 0.048, respectively. Furthermore, microsporidia infections was more prevalent among patients who had animals at home (p = 0.037). Conclusions: Study has shown a high prevalence of microsporidia among patients attending primary health centers in the Mopani District for the first time. Prevalence of microsporidia was higher among HIV negative and HIV positive patients who were not on ARV treatment. Keeping animals in the household appeared to be a risk of getting infected with microsporidia. Further studies are needed to determine the genetic characteristics of these organisms in the study population.

Background Very few studies have determined the prevalence and assemblage distribution of Giardia lamblia in South Africa. The present study aimed to ascertain the prevalence of G. lamblia infection and the spread of the various assemblages in two communities in South Africa - Giyani, Limpopo province (rural community) and Pretoria Guateng province (urban community). Methods Prevalence was determined by immunological and molecular methods analyzing a total of 516 stool samples collected from patients visiting different health centres in Giyani and Pretoria. For immunological assays, samples were screened by ELISA to detect G. lamblia antigen. Furthermore, a semi nested PCR amplifying the triose phosphate isomerase (tpi) gene was used to differentiate between the two most common human assemblages (A and B). Findings Of the 516 participants, 40 (7.75%) were identified as positive by ELISA. A statistically significant correlation was observed between the stool texture and Giardia infection (ᵡ2 = 10.533; p = .005). G. lamblia was significantly associated with watery stool types in females p = .008. Furthermore, a significant association was also noticed between the origin of samples (ᵡ2 = 9.725; p = .002). No significant correlation between age and gender was noted. Regarding the age groups, most people who were infected were between 3 and 20 years. A statistically significant association was seen (p = .001) with the distribution of the pathogen with the stool type. The prevalence of Giardia infection was higher in watery stool samples (71.4%) in Giyani region (rural) whereas in Pretoria, high prevalence was found in loose stool samples (6.2%). Generally, the distribution was statistically significant in the stool type collected for the study (p = .005). Genotyping revealed more G. lamblia assemblage B (17.8%) than assemblage A (1.7%). Furthermore, 21.0% of the samples exhibited single infection while 4.2% had mixed infections. Assemblage B was more common in Giyani than in urban Pretoria. Conclusions The study confirms Giardia as an important cause of diarrhea in the concerned communities with people in rural areas more at risk compared to those in urban areas with higher prevalence among younger patients. Therefore, health education campaigns should target young age groups.

This study reports a green synthesis route for a bilayered Ag-MgO nanocomposite using aqueous peel extract of Citrus paradisi (grapefruit red) under an accelerated uniform heating technique and its antibacterial potency against Escherichia coli. Surface modifications and composition of the nanocomposite were examined using a UV-visible spectrophotometer, transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM) equipped with an energy dispersive X-ray (EDX) analyzer. The efficiencies of the as-synthesized Ag-MgO nanocomposite against Escherichia coli were examined. The synthesized Ag-MgO nanocomposite showed characteristic synergetic bands at 290 nm for MgO nanoparticle and at around 440 nm for Ag nanoparticle which blue-shifted to 380 nm in the composite. A spherically dispersed nanocomposite with cubical crystal lattice network with a diameter of about 20–100 nm comprising Ag nanoparticle embedded within MgO nanoparticles was obtained. The nanocomposite produced stronger antibacterial activity against Escherichia coli as compared to MgO nanoparticle, indicating a higher interaction between Ag and MgO ions. The nanocomposite was successfully synthesized via an efficient modified method by bioreductive agents with an improved synergistic antibacterial property towards water purification.

Improving understanding of the pathogen-specific seasonality of enteric infections is critical to informing policy on the timing of preventive measures and to forecast trends in the burden of diarrhoeal disease. Data obtained from active surveillance of cohorts can capture the underlying infection status as transmission occurs in the community. The purpose of this study was to characterise rotavirus seasonality in eight different locations while adjusting for age, calendar time and within-subject clustering of episodes by applying an adapted Serfling model approach to data from a multi-site cohort study. In the Bangladesh and Peru sites, within-subject clustering was high, with more than half of infants who experienced one rotavirus infection going on to experience a second and more than 20% experiencing a third. In the five sites that are in countries that had not introduced the rotavirus vaccine, the model predicted a primary peak in prevalence during the dry season and, in three of these, a secondary peak during the rainy season. The patterns predicted by this approach are broadly congruent with several emerging hypotheses about rotavirus transmission and are consistent for both symptomatic and asymptomatic rotavirus episodes. These findings have practical implications for programme design, but caution should be exercised in deriving inferences about the underlying pathways driving these trends, particularly when extending the approach to other pathogens.

Background : Toxoplasma gondii is a zoonotic parasite that has arisen as an important opportunistic infection that causes morbidity and mortality especially in HIV positive patients. This study was carried out to determine the sero-prevalence of T. gondii (IgG and IgM) and the associated risk factors among HIV positive and negative patients in Northern South Africa. Materials and Methods : The study was conducted in the Vhembe District in Limpopo province from April 2012 to January 2013. A well-structured questionnaire was used to collect socio-demographic information and possible risk factor information on toxoplasmosis from participants. A total of 161 blood samples of both HIV positive and negative patients visiting the local clinics in the Vhembe district were collected. Serum samples were tested for IgG and IgM against T. gondii using commercially available ELISA protocol. Results : The prevalence of T. gondii IgG was 31.7% while that of T. gondii IgM was 4.9%. The prevalence of T. gondii IgG was higher in HIV positive patients (38%) compared to 16.7% among HIV negative patients (p=0.001). Toxoplasma gondii IgG antibodies were more common in patients who were not taking ARV’s (46.2%) compared to those who were taking ARV’s (35.2%) (P 25 years). Keywords : ELISA, HIV, Toxoplasma gondii, Sero-prevalence, Opportunistic infections.

Background In a multicountry birth cohort study, we describe rotavirus infection in the first 2 years of life in sites with and without rotavirus vaccination programs. Methods Children were recruited by 17 days of age and followed to 24 months with collection of monthly surveillance and diarrheal stools. Data on sociodemographics, feeding, and illness were collected at defined intervals. Stools were tested for rotavirus and sera for antirotavirus immunoglobulins by enzyme immunoassays. Results A total of 1737 children contributed 22646 surveillance and 7440 diarrheal specimens. Overall, rotavirus was detected in 5.5% (408/7440) of diarrheal stools, and 344 (19.8%) children ever had rotavirus gastroenteritis. Household overcrowding and a high pathogen load were consistent risk factors for infection and disease. Three prior infections conferred 74% (P < .001) protection against subsequent infection in sites not using vaccine. In Peru, incidence of rotavirus disease was relatively higher during the second year of life despite high vaccination coverage. Conclusions Rotavirus infection and disease were common, but with significant heterogeneity by site. Protection by vaccination may not be sustained in the second year of life in settings with high burdens of transmission and poor response to oral vaccines.