Soil-transmitted helminth infections among plantation sector schoolchildren in Sri Lanka: prevalence after ten years of preventive chemotherapy

Background

The plantation sector in Sri Lanka lags behind the rest of the country in terms of living conditions and health. In 1992, a sector-wide survey of children aged 3–12 years and women of reproductive age showed >90% prevalence of soil-transmitted helminth infections. Biannual mass de-worming targeting children aged 3–18 years started in 1994 and was continued until 2005. The present study was carried out to assess the status of infection four years after cessation of mass de-worming.

Methods/Findings

A school-based cross-sectional survey was carried out. Faecal samples from approximately 20 children from each of 114 schools in five districts were examined using the modified Kato-Katz technique. Data regarding the school, the child''s family and household sanitation were recorded after inspection of schools and households. Multivariate analysis was carried out using logistic regression, to identify risk factors for infection. Faecal samples were obtained from 1890 children. In 4/5 districts, >20% were infected with one or more helminth species. Overall combined prevalence was 29.0%; 11.6% had infections of moderate-heavy intensity. The commonest infection was Ascaris lumbricoides, present in all five districts, as was Trichuris trichiura. Hookworm was not detected in two districts. Multivariate analysis identified low altitude and maternal under-education as risk factors for all three infections. Poor household sanitation was identified as a risk factor for A. lumbricoides and hookworm, but not T. trichiura infections.

Conclusions/Significance

The results indicate that regular mass de-worming of plantation sector children should be resumed along with more emphasis on better sanitation and health education. They show that even after 10 years of mass chemotherapy, prevalence can bounce back after cessation of preventive chemotherapy, if the initial force of transmission is strong and other long-term control measures are not concomitantly implemented.     

The global burden of snakebite: a literature analysis and modelling based on regional estimates of envenoming and deaths

Background

Envenoming resulting from snakebites is an important public health problem in many tropical and subtropical countries. Few attempts have been made to quantify the burden, and recent estimates all suffer from the lack of an objective and reproducible methodology. In an attempt to provide an accurate, up-to-date estimate of the scale of the global problem, we developed a new method to estimate the disease burden due to snakebites.

Methods and Findings

The global estimates were based on regional estimates that were, in turn, derived from data available for countries within a defined region. Three main strategies were used to obtain primary data: electronic searching for publications on snakebite, extraction of relevant country-specific mortality data from databases maintained by United Nations organizations, and identification of grey literature by discussion with key informants. Countries were grouped into 21 distinct geographic regions that are as epidemiologically homogenous as possible, in line with the Global Burden of Disease 2005 study (Global Burden Project of the World Bank). Incidence rates for envenoming were extracted from publications and used to estimate the number of envenomings for individual countries; if no data were available for a particular country, the lowest incidence rate within a neighbouring country was used. Where death registration data were reliable, reported deaths from snakebite were used; in other countries, deaths were estimated on the basis of observed mortality rates and the at-risk population. We estimate that, globally, at least 421,000 envenomings and 20,000 deaths occur each year due to snakebite. These figures may be as high as 1,841,000 envenomings and 94,000 deaths. Based on the fact that envenoming occurs in about one in every four snakebites, between 1.2 million and 5.5 million snakebites could occur annually.

Conclusions

Snakebites cause considerable morbidity and mortality worldwide. The highest burden exists in South Asia, Southeast Asia, and sub-Saharan Africa.     

To keep or not to keep? the question of crystallographic waters for enzyme simulations in organic solvent

The use of enzymes in non-aqueous solvents expands the use of biocatalysts to hydrophobic substrates, with the ability to tune selectivity of reactions through solvent selection. Non-aqueous enzymology also allows for fundamental studies on the role of water and other solvents in enzyme structure, dynamics, and function. Molecular dynamics simulations serve as a powerful tool in this area, providing detailed atomic information about the effect of solvents on enzyme properties. However, a common protocol for non-aqueous enzyme simulations does not exist. If you want to simulate enzymes in non-aqueous solutions, how many and which crystallographic waters do you keep? In the present work, this question is addressed by determining which crystallographic water molecules lead most quickly to an equilibrated protein structure. Five different methods of selecting and keeping crystallographic waters are used in order to discover which crystallographic waters lead the protein structure to reach an equilibrated structure more rapidly in organic solutions. It is found that buried waters contribute most to rapid equilibration in organic solvent, with slow-diffusing waters giving similar results.     

Anther culture and haploid plant regeneration in purple coneflower (Echinacea purpurea L.)

Anthers containing microspores at the uninucleate stage were excised from capitula of field grown plants of purple coneflower, Echinacea purpurea, and cultured on medium conducive to callus growth. In callus induction cultures, N6 basal medium was more effective than Murashige and Skoog (MS), and a combination of benzyladenine (BA) at 2.22 μM with naphthaleneacetic acid (NAA) at 0.054 μM was more effective than 2,4-dichlorophenoxyacetic acid (2,4-D) alone at 4.52, 9.05 and 13.57 μM. Callus induction rate as high as 85.8% was achieved, and no statistically significant differences were found among cultures with various densities of 20, 40, 60, 80 and 100 anthers per bottle each filled with 40-ml medium. Shoots were regenerated from calluses on MS medium containing 2.22 μM BA and various concentrations of NAA, with the highest regeneration rate of 95.24% obtained when 0.27 μM NAA was applied. Although a large portion of the␣regenerated shoots had prominent symptom of vitrification, some normal shoots could be easily rooted on MS medium containing 0.054 μM NAA. Thirty regenerated plants were randomly selected and 19 of them were confirmed to be haploid by observation of chromosome number of root-tip cells.     

Babesia caballi and Babesia equi: implications of host sialic acids in erythrocyte infection

The present study investigated the involvement of host sialic acids in the erythrocyte infection by two equine Babesia parasites, Babesia equi and Babesia caballi. We observed that the in vitro growth of both parasites is influenced by the removal of sialic acids from the surface of equine erythrocytes (RBC). When the parasites were cultured with neuraminidase (Nm, EC 3.2.1.18)-treated RBC, in which alpha2-3-linked sialic acid residues were removed from four membrane proteins of the RBC, B. caballi showed a significant inhibition of the erythrocyte invasion, while the intracellular development of B. equi seemed to be significantly affected. The possible involvement of host sialic acid in the erythrocyte invasion by B. caballi was also supported by a significant reduction in the parasite growth accompanied by an increased number of extracellular merozoites after the addition of exogenous 3'-sialyllactose (Neu5Acalpha(2-3)Galbeta(1-4)Glc) into the culture. These results suggest that the alpha2-3-linked sialic acid residues on host RBC play important roles in the erythrocyte infections by B. caballi and B. equi.     

ACPA-positive and ACPA-negative rheumatoid arthritis differ in their requirements for combination DMARDs and corticosteroids: secondary analysis of a randomized controlled trial

Introduction

UK guidelines recommend that all early active rheumatoid arthritis (RA) patients are offered combination disease-modifying antirheumatic drugs (DMARDs) and short-term corticosteroids. Anti-citrullinated protein antibody (ACPA)-positive and ACPA-negative RA may differ in their treatment responses. We used data from a randomized controlled trial - the Combination Anti-Rheumatic Drugs in Early RA (CARDERA) trial - to examine whether responses to intensive combination treatments in early RA differ by ACPA status.

Methods

The CARDERA trial randomized 467 early active RA patients to receive: (1) methotrexate, (2) methotrexate/ciclosporin, (3) methotrexate/prednisolone or (4) methotrexate/ciclosporin/prednisolone in a factorial-design. Patients were assessed every six months for two years. In this analysis we evaluated 431 patients with available ACPA status. To minimize multiple testing we used a mixed-effects repeated measures ANOVA model to test for an interaction between ACPA and treatment on mean changes from baseline for each outcome (Larsen, disease activity scores on a 28-joint count (DAS28), Health Assessment Questionnaire (HAQ), EuroQol, SF-36 physical component summary (PCS) and mental component summary (MCS) scores). When a significant interaction was present, mean changes in outcomes were compared by treatment group at each time point using t-tests stratified by ACPA status. Odds ratios (ORs) for the onset of new erosions with treatment were calculated stratified by ACPA.

Results

ACPA status influenced the need for combination treatments to reduce radiological progression. ACPA-positive patients had significant reductions in Larsen score progression with all treatments. ACPA-positive patients receiving triple therapy had the greatest benefits: two-year mean Larsen score increases comprised 3.66 (95% confidence interval (CI) 2.27 to 5.05) with triple therapy and 9.58 (95% CI 6.76 to 12.39) with monotherapy; OR for new erosions with triple therapy versus monotherapy was 0.32 (95% CI 0.14 to 0.72; P = 0.003). ACPA-negative patients had minimal radiological progression irrespective of treatment. Corticosteroid’s impact on improving DAS28/PCS scores was confined to ACPA-positive RA.

Conclusions

ACPA status influences the need for combination DMARDs and high-dose tapering corticosteroids in early RA. In CARDERA, combination therapy was only required to prevent radiological progression in ACPA-positive patients; corticosteroids only provided significant disease activity and physical health improvements in ACPA-positive disease. This suggests ACPA is an important biomarker for guiding treatment decisions in early RA.

Trial registration

Current Controlled Trials ISRCTN32484878     

Prevalence of virulence and extended-spectrum β-lactamase (ESBL) genes harbouring Vibrio spp. isolated from cockles (Tegillarca granosa) marketed in Korea

This study aimed to examine incidence, virulence and antimicrobial properties in Aeromonas spp. isolated from cockles (Tegillarca granosa) in Korea. Firstly, genomic DNA was extracted from 32 Aeromonas spp. isolates, and PCR screening for virulence, antimicrobial resistance genes was carried out. The disk diffusion assay was used to examine antimicrobial susceptibility. Aeromonas spp. isolates comprised, A. hydrophila (n = 8), A. veronii (n = 15), A. media (n = 2), A. salmonicida (n = 2), A. allosaccharophila (n = 1), A. bestiarum (n = 1), A. culicicola (n = 1), A. enteropelogenes (n = 1) and A. rivipollensis (n = 1). High prevalence of virulence-related genes reported as; act (69%), alt (47%), ast (41%), aerA (56%), lip (50%), ahyB (47%), ser (28%), fla (66%), gcat (44%), ascV (50%) and hlyA (72%). All isolates were multidrug resistant, while highest resistance level observed for ampicillin (100%), followed by imipenem (81%), rifampicin (78%), cephalothin (72%), piperacillin (47%) and Colistin sulfate (31%). The presence of bla_SHV, bla_CTX, tetE, aac(6’)-Ib, strA-strB, qnrS, qnrB and IntI1 genes were reported in varying combinations. Nevertheless, bla_TEM, bla_IMP, tetA, tetB, qnrA, qnrB and aphAI-IAB genes and the class1 integron were not detected. The high occurrence of virulence and antimicrobial resistance genes in cockles reveals that it can be a potential health risk source for consumers.