Entamoeba and Giardia parasites implicated as hosts of CRESS viruses.

Metagenomic techniques have enabled genome sequencing of unknown viruses without isolation in cell culture, but information on the virus host is often lacking, preventing viral characterisation. High-throughput methods capable of identifying virus hosts based on genomic data alone would aid evaluation of their medical or biological relevance. Here, we address this by linking metagenomic discovery of three virus families in human stool samples with determination of probable hosts. Recombination between viruses provides evidence of a shared host, in which genetic exchange occurs. We utilise networks of viral recombination to delimit virus-host clusters, which are then anchored to specific hosts using (1) statistical association to a host organism in clinical samples, (2) endogenous viral elements in host genomes, and (3) evidence of host small RNA responses to these elements. This analysis suggests two CRESS virus families (Naryaviridae and Nenyaviridae) infect Entamoeba parasites, while a third (Vilyaviridae) infects Giardia duodenalis. The trio supplements five CRESS virus families already known to infect eukaryotes, extending the CRESS virus host range to protozoa. Phylogenetic analysis implies CRESS viruses infecting multicellular life have evolved independently on at least three occasions

A simple and fast method to exclude high Plasmodium falciparum parasitaemia in travellers with imported malaria

Background: Counts of malaria parasites in peripheral blood are important to assess severity of Plasmodium falciparum malaria. Thin and thick smears are routinely used for this purpose. Methods. In this study the Binax NOW® Malaria Test, an easy-to-perform rapid diagnostic test, with Histidine Rich Protein-2 (HRP-2) and aldolase as diagnostic markers, was used for semi-quantitative assessment of parasitaemia of P. faciparum. Results: In 257 patients with imported P. falciparum malaria, reactivity of aldolase increased with higher parasitaemia. In all patients with a parasitaemia above 50,000 asexual parasites/l (> 1%) co-reactivity of HRP-2 and aldolase was observed. Absence of aldolase reactivity in the presence of HRP-2 was a reliable predictive marker to exclude high (> 1%) parasitaemia in P. falciparum malaria. Conclusions: Assessment of HRP-2 and aldolase co-reactivity can be of help in clinical decision making in the acute care setting of returning travellers suspected of having malaria

Improved general health of international adoptees, but immunization status still insufficient

We studied the demographic and clinical data from 495 adopted children seen between January 2002 and January 2007 to evaluate the medical condition and immunization status of international adoptees. The data of children from Chinese origin (53.5%) were compared to children arriving from other countries. Medical problems requiring treatment were present in 42.8% of the children. Parasitic gastrointestinal infection (22.0%) and skin abnormalities (22.4%) were diagnosed most often. Hepatitis B (1.2%) and tuberculosis (1%) were documented in some children; HIV, hepatitis C, and syphilis were not seen in any of the children. Antibody levels against diphtheria and tetanus were insufficient in about half of all children, particularly in those from China. In conclusion, most adoptive children had a good general health, with only a few having major medical problems. Many adoptive children had an inadequate immunization status

Travel-related schistosomiasis, strongyloidiasis, filariasis, and toxocariasis: the risk of infection and the diagnostic relevance of blood eosinophilia

<p>Abstract</p> <p>Background</p> <p>This study prospectively assessed the occurrence of clinical and subclinical schistosomiasis, strongyloidiasis, filariasis, and toxocariasis, and the screening value of eosinophilia in adult short-term travelers to helminth-endemic countries.</p> <p>Methods</p> <p>Visitors of a pre-travel health advice centre donated blood samples for serology and blood cell count before and after travel. Samples were tested for eosinophilia, and for antibodies against schistosomiasis, strongyloidiasis, filariasis, and toxocariasis. Previous infection was defined as seropositivity in pre- and post-travel samples. Recent infection was defined as a seroconversion. Symptoms of parasitic disease were recorded in a structured diary.</p> <p>Results</p> <p>Previous infection was found in 112 of 1207 subjects: schistosomiasis in 2.7%, strongyloidiasis in 2.4%, filariasis in 3.4%, and toxocariasis in 1.8%. Recent schistosomiasis was found in 0.51% of susceptible subjects at risk, strongyloidiasis in 0.25%, filariasis in 0.09%, and toxocariasis in 0.08%. The incidence rate per 1000 person-months was 6.4, 3.2, 1.1, and 1.1, respectively. Recent infections were largely contracted in Asia. The positive predictive value of eosinophilia for diagnosis was 15% for previous infection and 0% for recent infection. None of the symptoms studied had any positive predictive value.</p> <p>Conclusion</p> <p>The chance of infection with schistosomiasis, strongyloidiasis, filariasis, and toxocariasis during one short-term journey to an endemic area is low. However, previous stay leads to a cumulative risk of infection. Testing for eosinophilia appeared to be of no value in routine screening of asymptomatic travelers for the four helminthic infections. Findings need to be replicated in larger prospective studies.</p

Snf2 family ATPases and DExx box helicases:differences and unifying concepts from high-resolution crystal structures

Proteins with sequence similarity to the yeast Snf2 protein form a large family of ATPases that act to alter the structure of a diverse range of DNA–protein structures including chromatin. Snf2 family enzymes are related in sequence to DExx box helicases, yet they do not possess helicase activity. Recent biochemical and structural studies suggest that the mechanism by which these enzymes act involves ATP-dependent translocation on DNA. Crystal structures suggest that these enzymes travel along the minor groove, a process that can generate the torque or energy in remodelling processes. We review the recent structural and biochemical findings which suggest a common mechanistic basis underlies the action of many of both Snf2 family and DExx box helicases

Carriage of Blastocystis spp. in travellers - A prospective longitudinal study

Introduction: A lack of prospective and longitudinal data on pre- and post-travel carriage of Blastocystis spp. complicates interpretation of a positive test post-travel. Therefore we studied dynamics of Blastocystis carriage in a cohort of Dutch travellers. Methods: From the prospective, multicentre COMBAT study among 2001 Dutch travellers, a subset of 491 travellers was selected based on travel destination to 7 subregions (70 or 71 travellers each). Faecal samples taken directly before and after travel were screened for Blastocystis with qPCR, followed, when positive, by sequence analysis to determine subtypes. Results: After exclusion of 12 samples with missing samples or inhibited qPCR-reactions, stool samples of 479 travellers were analysed. Before travel, 174 of them (36.3%) carried Blastocystis and in most of these, the same subtype was persistently carried. However, in 48/174 of those travellers (27.6%; CI95 20.8–36.6%) no Blastocystis or a different subtype was detected in the post-travel sample, indicating loss of Blastocystis during travel. Only 26 (5.4%; CI95 3.7%–8.0%) of all travellers acquired Blastocystis, including two individuals that were already positive for Blastocystis before travel but acquired a different subtype during travel. Discussion: This study shows that Blastocystis carriage in travellers is highly dynamic. The observed acquisition and loss of Blastocystis could either be travel-related or reflect the natural course of Blastocystis carriage. We demonstrate that the majority of Blastocystis detected in post-travel samples were already carried before travel

Linkage study of 14 candidate genes and loci in four large Dutch families with vesico-ureteral reflux

Vesico-ureteral reflux (VUR) is a major contributing factor to end-stage renal disease in paediatric patients. Primary VUR is a familial disorder, but little is known about its genetic causes. To investigate the involvement of 12 functional candidate genes and two reported loci in VUR, we performed a linkage study in four large, Dutch, multi-generational families with multiple affected individuals. We were unable to detect linkage to any of the genes and loci and could exclude the GDNF, RET, SLIT2, SPRY1, PAX2, AGTR2, UPK1A and UPK3A genes and the 1p13 and 20p13 loci from linkage to VUR. Our results provide further evidence that there appears to be genetic heterogeneity in VUR

Parasitic, bacterial, viral, immune-mediated, metabolic, and nutritional factors associated with Nodding syndrome

Nodding syndrome is a neglected, disabling and potentially fatal epileptic disorder of unknown aetiology affecting thousands of individuals mostly confined to Eastern sub-Saharan Africa. Previous studies have identified multiple associations – including O. volvulus, antileiomodin-1 antibodies, vitamin B6 deficiency, and measles virus infection – yet none is proven causal. We conducted a case-control study of children with early-stage Nodding syndrome (symptom onset &amp;lt;1 year). Cases and controls were identified through a household survey in the Greater Mundri area in South Sudan. A wide range of parasitic, bacterial, viral, immune-mediated, metabolic, and nutritional risk factors was investigated using conventional and state-of-the-art untargeted assays. Associations were examined by multiple logistic regression analysis and a hypothetical causal model was constructed using structural equation modelling. From 607 children with Nodding syndrome, 72 with early-stage disease were included as cases and matched to 65 household- and 44 community controls. Mansonella perstans infection (odds ratio [OR] 7.04, 95% confidence interval [CI] 2.28-21.7), Necator americanus infection (OR 2.33, 95% CI 1.02-5.3), higher antimalarial seroreactivity (OR 1.75, 95% CI 1.20-2.57), higher vitamin E concentration (OR 1.53 per standard deviation [SD] increase, 95% CI 1.07-2.19) and lower vitamin B12 concentration (OR 0.56 per SD increase, 95% CI 0.36-0.87) were associated with higher odds of NS. In a structural equation model, we hypothesized that M. perstans infection, higher vitamin E concentration and fewer viral exposures increased the risk of Nodding syndrome while lower vitamin B12 concentration, N. americanus and malaria infections resulted from having Nodding syndrome. We found no evidence that O. volvulus, antileiomodin-1 antibodies, vitamin B6 and other factors were associated with Nodding syndrome. Our results argue against several previous causal hypotheses including O. volvulus. Instead, Nodding syndrome may be caused by a complex interplay between multiple pathogens and nutrient levels. Further studies need to confirm these associations and determine the direction of effect