Low Endemic Settings Research Articles

Plasmodium falciparum Drug-Resistant Haplotypes and Population Structure in Postearthquake Haiti, 2010.

Chloroquine (CQ) remains the first-line treatment of malaria in Haiti. Given the challenges of conducting in vivo drug efficacy trials in low-endemic settings like Haiti, molecular surveillance for drug resistance markers is a reasonable approach for detecting resistant parasites. In this study, 349 blood spots were collected from suspected malaria cases in areas in and around Port-au-Prince from March to July 2010. Among them, 121 samples that were Plasmodium falciparum positive by polymerase chain reaction were genotyped for drug-resistant pfcrt, pfdhfr, pfdhps, and pfmdr1 alleles. Among the 108 samples that were successfully sequenced for CQ resistant markers in pfcrt, 107 were wild type (CVMNK), whereas one sample carried a CQ-resistant allele (CVIET). Neutral microsatellite genotyping revealed that the CQ-resistant isolate was distinct from all other samples in this study. Furthermore, the remaining parasite specimens appeared to be genetically distinct from other reported Central and South American populations.

Evaluation of a multiplex real-time PCR kit Amplidiag® Bacterial GE in the detection of bacterial pathogens from stool samples

This study evaluated the performance of a new commercially available multiplex real-time PCR kit Amplidiag® Bacterial GE in the systematic screening of bacterial pathogens causing gastroenteritis. Stool samples from 1168 patients were analyzed with Amplidiag® Bacterial GE, stool culture, and molecular reference tests, and the sensitivity and specificity of Amplidiag® Bacterial GE were determined by comparing the results to the reference tests. The evaluation showed good performance for Amplidiag® Bacterial GE: sensitivity and specificity of the test was 100/99.7% for Salmonella, 100/99.8% for Yersinia, 98.8/99.2% for Campylobacter, 92.9/100% for Shigella/EIEC, 100/99.9% for EHEC, 92.9/99.8% for ETEC, 98.9/99.2% for EPEC, and 100/99.8% EAEC, respectively. When compared with stool culture, Amplidiag® Bacterial GE was found to be more sensitive. This study suggests that Amplidiag® Bacterial GE is suitable for screening bacterial pathogens from stool samples. However, this study only demonstrates the performance of Amplidiag® Bacterial GE in low endemic settings, as the number of positive findings in this study was relatively low.

Loop-mediated isothermal amplification assay for detection of Mycobacterium tuberculosis complex in infertile women

Background: Female genital tuberculosis (FGTB) has a profound impact on the reproductive health of patients including infertility. Conventional diagnostic techniques have low sensitivity and specificity as well as long turnaround time. There is a need of developing newer, rapid and practically adaptable technique, especially in low-income countries. Objective: To standardize and evaluate loop-mediated isothermal amplification (LAMP) technique for diagnosis of FGTB. Methods: A total of 300 endometrial biopsy samples from infertile females were subjected to Ziehl–Neelsen (ZN) staining, Lowenstein–Jensen culture, automated culture (BACTEC mycobacterial growth indicator tube), histopathological examination (HPE), nucleic acid amplification by polymerase chain reaction (PCR) and LAMP technique. Composite gold standard (either smear/culture/HPE/PCR positive) was considered for calculation of outcome parameters. Results: The observed sensitivities of ZN smear, culture, HPE, PCR and LAMP were 2.94%, 10.29%, 8.82%, 95.59% and 66.18%, respectively. Overall concordance between PCR and LAMP was 63%, which shows a good agreement. Conclusion: This study is the first to evaluate LAMP in the diagnosis of FGTB and found it to be a rapid and convenient technique, especially in low resource endemic settings.

Efficacy of topical mosquito repellent (picaridin) plus long-lasting insecticidal nets versus long-lasting insecticidal nets alone for control of malaria: a cluster randomised controlled trial

Although effective topical repellents provide personal protection against malaria, whether mass use of topical repellents in addition to long-lasting insecticidal nets can contribute to a further decline of malaria is not known, particularly in areas where outdoor transmission occurs. We aimed to assess the epidemiological efficacy of a highly effective topical repellent in addition to long-lasting insecticidal nets in reducing malaria prevalence in this setting. A cluster randomised controlled trial was done in the 117 most endemic villages in Ratanakiri province, Cambodia, to assess the efficacy of topical repellents in addition to long-lasting insecticidal nets in controlling malaria in a low-endemic setting. We did a pre-trial assessment of village accessibility and excluded four villages because of their inaccessibility during the rainy season. Another 25 villages were grouped because of their proximity to each other, resulting in 98 study clusters (comprising either a single village or multiple neighbouring villages). Clusters were randomly assigned (1:1) to either a control (long-lasting insecticidal nets) or intervention (long-lasting insecticidal nets plus topical repellent) study group after a restricted randomisation. All clusters received one long-lasting insecticidal net per individual, whereas those in the intervention group also received safe and effective topical repellents (picaridin KBR3023, SC Johnson, Racine, WI, USA), along with instruction and promotion of its daily use. Cross-sectional surveys of 65 randomly selected individuals per cluster were done at the beginning and end of the malaria transmission season in 2012 and 2013. The primary outcome was Plasmodium species-specific prevalence in participants obtained by real-time PCR, assessed in the intention-to-treat population. Complete safety analysis data will be published seperately; any ad-hoc adverse events are reported here. This trial is registered with ClinicalTrials.gov, number NCT01663831. Of the 98 clusters that villages were split into, 49 were assigned to the control group and 49 were assigned to the intervention group. Despite having a successful distribution system, the daily use of repellents was suboptimum. No post-intervention differences in PCR plasmodium prevalence were observed between study groups in 2012 (4·91% in the control group vs 4·86% in the intervention group; adjusted odds ratio [aOR] 1·01 [95% CI 0·60-1·70]; p=0·975) or in 2013 (2·96% in the control group vs 3·85% in the intervention group; aOR 1·31 [0·81-2·11]; p=0·266). Similar results were obtained according to Plasmodium species (1·33% of participants in the intervention group vs 1·10% in the intervention group were infected with Plasmodium falciparum; aOR 0·83 [0·44-1·56]; p=0·561; and 1·85% in the control group vs 2·67% in the intervention group were infected with Plasmodium vivax; aOR 1·51 [0·88-2·57]; p=0·133). 41 adverse event notifications from nine villages were received, of which 33 were classified as adverse reactions (11 of these 33 were cases of repellent abuse through oral ingestion, either accidental or not). All participants with adverse reactions fully recovered and 17 were advised to permanently stop using the repellent. Mass distribution of highly effective topical repellents in resource-sufficient conditions did not contribute to a further decline in malaria endemicity in a pre-elimination setting in the Greater Mekong subregion. Daily compliance and appropriate use of the repellents remains the main obstacle. Bill & Melinda Gates Foundation.

Spectrum of Choroidal Involvement in Presumed Ocular Tuberculosis: Report from a Population with Low Endemic Setting for Tuberculosis

ABSTRACTObjective: To describe the clinical spectrum and outcome of patients with presumed tubercular uveitis and choroidal involvement.Methods: A retrospective case series nested in a cohort study was enrolled at a tertiary referral eye care center in the UK. Failure was defined as recurrence of lesion within 6 months of completion of antitubercular therapy (ATT) or corticosteroid therapy.Results: Seventy-seven patients with presumed ocular tuberculosis and choroidal involvement were included in the study. Mean age was 45.5 ± 15.7 years, 44 (57.1%) patients were male, and 51 (66.2%) presented with bilateral disease. Choroidal granuloma was the most frequent clinical presentation (n = 27, 35.07%), followed by multifocal choroiditis (n = 24, 31.17%) and serpiginous-like choroiditis (n = 18, 23.38%). Quantiferon Gold in Tube Test (QFT) was positive in 64 (83.11%) patients. Fifty (64.94%) patients received ATT.Conclusions: Choroidal involvement in presumed ocular tuberculosis can present with a variable spectrum. Treatment failure rates were equivalent between ATT and non-ATT treated groups.

Feasibility of eliminating visceral leishmaniasis from the Indian subcontinent: explorations with a set of deterministic age-structured transmission models

BackgroundVisceral leishmaniasis (VL) is a neglected tropical disease transmitted by sandflies. On the Indian subcontinent (ISC), VL is targeted for elimination as a public health problem by 2017. In the context of VL, the elimination target is defined as an annual VL incidence of <1 per 10,000 capita at (sub-)district level. Interventions focus on vector control, surveillance and on diagnosing and treating VL cases. Many endemic areas have not yet achieved optimal control due to logistical, biological as well as technical challenges. We used mathematical modelling to quantify VL transmission dynamics and predict the feasibility of achieving the VL elimination target with current control strategies under varying assumptions about the reservoir of infection in humans.MethodsWe developed three deterministic age-structured transmission models with different main reservoirs of infection in humans: asymptomatic infections (model 1), reactivation of infection after initial infection (model 2), and post kala-azar dermal leishmaniasis (PKDL; model 3). For each model, we defined four sub-variants based on different assumptions about the duration of immunity and age-patterns in exposure to sandflies. All 12 model sub-variants were fitted to data from the KalaNet study in Bihar (India) and Nepal, and the best sub-variant was selected per model. Predictions were made for optimal and sub-optimal indoor residual spraying (IRS) effectiveness for three different levels of VL endemicity.ResultsStructurally different models explained the KalaNet data equally well. However, the predicted impact of IRS varied substantially between models, such that a conclusion about reaching the VL elimination targets for the ISC heavily depends on assumptions about the main reservoir of infection in humans: asymptomatic cases, recovered (immune) individuals that reactivate, or PKDL cases.ConclusionsAvailable data on the impact of IRS so far suggest one model is probably closest to reality (model 1). According to this model, elimination of VL (incidence of <1 per 10,000) by 2017 is only feasible in low and medium endemic settings with optimal IRS. In highly endemic settings and settings with sub-optimal IRS, additional interventions will be required.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1292-0) contains supplementary material, which is available to authorized users.

Factors influencing the use of topical repellents: implications for the effectiveness of malaria elimination strategies.

In Cambodia, despite an impressive decline in prevalence over the last 10 years, malaria is still a public health problem in some parts of the country. This is partly due to vectors that bite early and outdoors reducing the effectiveness of measures such as Long-Lasting Insecticidal Nets. Repellents have been suggested as an additional control measure in such settings. As part of a cluster-randomized trial on the effectiveness of topical repellents in controlling malaria infections at community level, a mixed-methods study assessed user rates and determinants of use. Repellents were made widely available and Picaridin repellent reduced 97% of mosquito bites. However, despite high acceptability, daily use was observed to be low (8%) and did not correspond to the reported use in surveys (around 70%). The levels of use aimed for by the trial were never reached as the population used it variably across place (forest, farms and villages) and time (seasons), or in alternative applications (spraying on insects, on bed nets, etc.). These findings show the key role of human behavior in the effectiveness of malaria preventive measures, questioning whether malaria in low endemic settings can be reduced substantially by introducing measures without researching and optimizing community involvement strategies.

Sensitivity and Specificity of a Urine Circulating Anodic Antigen Test for the Diagnosis of Schistosoma haematobium in Low Endemic Settings.

BackgroundElimination of schistosomiasis as a public health problem and interruption of transmission in selected areas are key goals of the World Health Organization for 2025. Conventional parasitological methods are insensitive for the detection of light-intensity infections. Techniques with high sensitivity and specificity are required for an accurate diagnosis in low-transmission settings and verification of elimination. We determined the accuracy of a urine-based up-converting phosphor-lateral flow circulating anodic antigen (UCP-LF CAA) assay for Schistosoma haematobium diagnosis in low-prevalence settings in Zanzibar, Tanzania.MethodologyA total of 1,740 urine samples were collected in 2013 from children on Pemba Island, from schools where the S. haematobium prevalence was <2%, 2–5%, and 5–10%, based on a single urine filtration. On the day of collection, all samples were tested for microhematuria with reagent strips and for the presence of S. haematobium eggs with microscopy. Eight months later, 1.5 ml of urine from each of 1,200 samples stored at -20°C were analyzed by UCP-LF CAA assay, while urine filtration slides were subjected to quality control (QCUF). In the absence of a true ‘gold’ standard, the diagnostic performance was calculated using latent class analyses (LCA).Principal FindingsThe ‘empirical’ S. haematobium prevalence revealed by UCP-LF CAA, QCUF, and reagent strips was 14%, 5%, and 4%, respectively. LCA revealed a sensitivity of the UCP-LF CAA, QCUF, and reagent strips of 97% (95% confidence interval (CI): 91–100%), 86% (95% CI: 72–99%), and 67% (95% CI: 52–81%), respectively. Test specificities were consistently above 90%.Conclusions/SignificanceThe UCP-LF CAA assay shows high sensitivity for the diagnosis of S. haematobium in low-endemicity settings. Empirically, it detects a considerably higher number of infections than microscopy. Hence, the UCP-LF CAA employed in combination with QCUF, is a promising tool for monitoring and surveillance of urogenital schistosomiasis in low-transmission settings targeted for elimination.

Mass drug administration for trachoma: how long is not long enough?

BackgroundBlinding trachoma is targeted for elimination by 2020 using the SAFE strategy (Surgery, Antibiotics, Facial cleanliness, and Environmental improvements). Annual mass drug administration (MDA) with azithromycin is a cornerstone of this strategy. If baseline prevalence of clinical signs of trachomatous inflammation – follicular among 1-9 year-olds (TF1-9) is ≥10% but <30%, the World Health Organization guidelines are for at least 3 annual MDAs; if ≥30%, 5. We assessed the likelihood of achieving the global elimination target of TF1-9 <5% at 3 and 5 year evaluations using program reports.Methodology/Principal FindingsWe used the International Trachoma Initiative’s prevalence and treatment database. Of 283 cross-sectional survey pairs with baseline and follow-up data, MDA was conducted in 170 districts. Linear and logistic regression modeling was applied to these to investigate the effect of MDA on baseline prevalence. Reduction to <5% was less likely, though not impossible, at higher baseline TF1-9 prevalences. Increased number of annual MDAs, as well as no skipped MDAs, were significant predictors of reduced TF1-9 at follow-up. The probability of achieving the <5% target was <50% for areas with ≥30% TF1-9 prevalence at baseline, even with 7 or more continuous annual MDAs.ConclusionsNumber of annual MDAs alone appears insufficient to predict program progress; more information on the effects of baseline prevalence, coverage, and underlying environmental and hygienic conditions is needed. Programs should not skip MDAs, and at prevalences >30%, 7 or more annual MDAs may be required to achieve the target. There are five years left before the 2020 deadline to eliminate blinding trachoma. Low endemic settings are poised to succeed in their elimination goals. However, newly-identified high prevalence districts warrant immediate inclusion in the global program. Intensified application of the SAFE strategy is needed in order to guarantee blinding trachoma elimination by 2020.

α-Thalassaemia trait is associated with antibody prevalence against malaria antigens AMA-1 and MSP-1.

A longitudinal study was conducted in a low endemic area in northern Tanzania to examine the influence of the α-thalassaemia trait on malaria incidence and antibody responses to malaria apical membrane antigen-1 (AMA-1) and merozoite surface protein1-19 (MSP-119). Out of 394 children genotyped for α-thalassaemia trait, 4.1% (16 of 394) and 30.7% (121 of 394) were homozygous and heterozygous, respectively. During the 1 year follow-up, four incidents of malaria cases were detected without an evident association with α-thalassaemia. Being heterozygous or homozygous for α-thalassaemia was associated with an increased prevalence of antibodies to AMA-1 [odds ratio (OR): 1.83, 95% confidence interval (CI): 1.07-3.12, p = 0.027] and MSP-1 (OR: 2.04, 95% CI: 1.16-3.60, p = 0.013) after adjustment for age and reported bednet use. The observed association between α-thalassaemia and malaria antibody responses may reflect longer-term differences in antigen exposure or differences in antibody acquisition upon exposure in this low endemic setting.

Evaluation of the loop mediated isothermal DNA amplification (LAMP) kit for malaria diagnosis in P. vivax endemic settings of Colombia.

BackgroundMost commonly used malaria diagnostic tests, including microscopy and antigen-detecting rapid tests, cannot reliably detect low-density infections which are frequent in low transmission settings. Molecular methods such as polymerase chain reaction (PCR) are highly sensitive but remain too laborious for field deployment. In this study, the applicability of a malaria diagnosis kit based on loop-mediated isothermal amplification (mLAMP) was assessed in malaria endemic areas of Colombia with Plasmodium vivax predominance.Methodology/Principal FindingsFirst, a passive case detection (PCD) study on 278 febrile patients recruited in Tierralta (department of Cordoba) was conducted to assess the diagnostic performance of the mLAMP method. Second, an active case detection (ACD) study on 980 volunteers was conducted in 10 sentinel sites with different epidemiological profiles. Whole blood samples were processed for microscopic and mLAMP diagnosis. Additionally RT-PCR and nested RT-PCR were used as reference tests. In the PCD study, P. falciparum accounted for 23.9% and P. vivax for 76.1% of the infections and no cases of mixed-infections were identified. Microscopy sensitivity for P. falciparum and P. vivax were 100% and 86.1%, respectively. mLAMP sensitivity for P. falciparum and P. vivax was 100% and 91.4%, respectively. In the ACD study, mLAMP detected 65 times more cases than microscopy. A high proportion (98.0%) of the infections detected by mLAMP was from volunteers without symptoms.Conclusions/SignificancemLAMP sensitivity and specificity were comparable to RT-PCR. LAMP was significantly superior to microscopy and in P. vivax low-endemicity settings and under minimum infrastructure conditions, it displayed sensitivity and specificity similar to that of single-well RT-PCR for detection of both P. falciparum and P. vivax infections. Here, the dramatically increased detection of asymptomatic malaria infections by mLAMP demonstrates the usefulness of this new tool for diagnosis, surveillance, and screening in elimination strategies.

Association between allergic responses and Schistosoma mansoni infection in residents in a low-endemic setting in Brazil.

Schistosomiasis is endemic in 76 countries and territories. Several studies have found an inverse correlation between parasitic disease and the development of allergies. The purpose of the present study was to determine whether infection with Schistosoma mansoni in subjects with a low parasite load is protective against allergy. The final sample consisted of 39 S. mansoni-positive and 52 S. mansoni-negative residents of a small community in northeastern Brazil. All subjects were submitted to the Kato-Katz test, anti-S. mansoni IgG measurement, the prick test for aeroallergens, eosinophil counts and serum IgE measurement. Subjects who reacted to one or more antigens in the prick test were considered allergic. Only 7 S. mansoni-positive subjects (17.9%) reacted to one or more antigens, whereas 20 S. mansoni-negative subjects (38.5%) tested positive for allergy. Our findings suggest that, in areas of low endemicity, infection with S. mansoni significantly reduces the risk of the development of allergy in subjects with a low parasite load.

HIV patients with latent tuberculosis living in a low-endemic country do not develop active disease during a 2year follow-up; a Norwegian prospective multicenter study.

BackgroundInterferon-γ release assays (IGRA) serve as immunodiagnostics of tuberculosis (TB) infection to identify individuals with latent TB infection (LTBI) eligible for preventive anti-TB therapy. In this longitudinal study of HIV-infected LTBI patients we have observed for possible progression to active TB as well as evaluated repeated IGRA testing in a TB low-endemic setting.MethodsQuantiFERON TB-Gold In-tube® assay (QFT), TB-SPOT.TB® (TSPOT) and tuberculin skin test (TST) were performed on 298 HIV-patients recruited from seven out-patient clinics in Norway. Patients with active TB, LTBI and negative IGRA were followed with repeat QFTs and clinical evaluation over a period of 24 months.ResultsSeven HIV-patients (median CD4 count 270; IQR 50–340) were diagnosed with active TB at inclusion, all IGRA positive. Sixty-four (21%) HIV-patients (median CD4 count 471; IQR 342–638) were diagnosed with LTBI and of these 39 (61%) received TB preventive treatment. Neither treated nor untreated HIV-infected LTBI patients developed active TB during the 24 months. At baseline, the median interferon-γ (INF-γ) level measured by QFT was 3.48 IU/ml (IQR 0.94 – 8.91 IU/ml) for treated LTBI compared to 1.13 IU/ml (IQR 0.47 – 4.25 IU/ml) for untreated LTBI patients (p = 0.029). The QFT reversion rates were 75% for active TB, 23% for treated LTBI and 44% for untreated LTBI, whereas the conversion rate for the non-TB group was 7% despite no new TB exposure. There was no significant difference in the trend of INF-γ levels over time between treated and untreated LTBI patients.ConclusionThe prevalence of LTBI is high among HIV-patients, but the risk of developing active TB seems to be low in patients with high CD4 counts in this TB low-endemic setting. In several patients, especially with baseline IFN-γ levels close to cut-offs, the QFT tests reverted to negative independent of preventive anti-TB treatment indicating possibly false positive tests. This highlights the importance of defining reliable cut-offs for immunodiagnostic tests and deferring preventive therapy in selected patients. Randomized studies with longer follow-up time are needed to identify HIV-patients that would benefit from LTBI treatment in a TB low-endemic setting.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-014-0667-0) contains supplementary material, which is available to authorized users.

Comparison of detection methods to estimate asexual Plasmodium falciparum parasite prevalence and gametocyte carriage in a community survey in Tanzania

BackgroundThe use of molecular techniques to detect malaria parasites has been advocated to improve the accuracy of parasite prevalence estimates, especially in moderate to low endemic settings. Molecular work is time-consuming and costly, thus the effective gains of this technique need to be carefully evaluated. Light microscopy (LM) and rapid diagnostic tests (RDT) are commonly used to detect malaria infection in resource constrained areas, but their limited sensitivity results in underestimation of the proportion of people infected with Plasmodium falciparum. This study aimed to evaluate the extent of missed infections via a community survey in Tanzania, using polymerase chain reaction (PCR) to detect P. falciparum parasites and gametocytes.MethodsThree hundred and thirty individuals of all ages from the Kilombero and Ulanga districts (Tanzania) were enrolled in a cross-sectional survey. Finger prick blood samples were collected for parasite detection by RDT, LM and molecular diagnosis using quantitative 18S rRNA PCR and msp2 nPCR. Gametocytes were detected by LM and by amplifying transcripts of the gametocyte-specific marker pfs25.ResultsResults from all three diagnostic methods were available for a subset of 226 individuals. Prevalence of P. falciparum was 38% (86/226; 95% CI 31.9–44.4%) by qPCR, 15.9% (36/226; 95% CI 11.1–20.7%) by RDT and 5.8% (13/226; 95% CI 2.69- 8.81%) by LM. qPCR was positive for 72% (26/36) of the RDT-positive samples. Gametocyte prevalence was 10.6% (24/226) by pfs25-qRT-PCR and 1.2% by LM.ConclusionsLM showed the poorest performance, detecting only 15% of P. falciparum parasite carriers identified by PCR. Thus, LM is not a sufficiently accurate technique from which to inform policies and malaria control or elimination efforts. The diagnostic performance of RDT was superior to that of LM. However, it is also insufficient when precise prevalence data are needed for monitoring intervention success or for determining point prevalence rates in countrywide surveillance. Detection of gametocytes by PCR was 10-times more sensitive than by LM. These findings support the need for molecular techniques to accurately estimate the human infectious reservoir and hence the transmission potential in a population.

Implementation of a new model for TB-care in a low endemic setting: A challenge in vain?

Aim and objectivesTo evaluate the implementation of an outpatient TB-clinic in a low-endemic setting. BackgroundIn May 2014 the World Health Organization (WHO) approved the post-2015 global tuberculosis (TB) strategy including the plan for elimination of TB in low-endemic countries. Sweden is a low-endemic country, but accepts large numbers of immigrants (e.g. 116,000 in 2013) and a majority from countries where TB is common.In order to prevent TB and ensure accessibility a new outpatient clinic for adults was initiated at a specialist hospital in a suburb of Gothenburg, Sweden, in February 2014. The population living in this suburd is overrepresented among the active cases of TB and in some subgroups the incidence is equal or even higher than in high-endemic countries. The objective is early detection and treatment of active disease and latent TB infection (LTBI) in a social medical perspective. MethodsA descriptive approach made from the experiences of the authors. ResultsThe TB-care in Gothenburg has, before 2014, been centralized to the university hospital. A political decision was taken in 2012, in line with the global TB strategy, to start an outpatient clinic where TB is overrepresented in the population. The decision was to be implemented through collaboration with all healthcare providers. The new clinic was aiming to promote redistribution of patients between the hospitals with an emphasis on accessibility for the patient. The decision was made without the involvement of management and clinical staff. As a result the clinic has solely been able to focus its care on finding LTBI and spreading knowledge and awareness of TB in high-risk groups. ConclusionA new approach of specialist healthcare is decentralization with emphasis on accessibility, improved preventive possibility and knowledge about the setting. This approach is well suited for TB elimination in order to target high-risk groups. The transition does not occur automatically, and commitment and knowledge is needed on every level in the healthcare system. A political basis is necessary, but for success and change the decision has to be established and anchored among management and healthcare staff. To treat TB-patients at an outpatient specialist clinic is economically beneficial and above all causes a positive effect on the patient’s psychosocial well-being and adherence to treatment. Unfortunately, the present infrastructure of TB-care in Sweden, as well as the will and knowledge of the staff to adapt and change according to the political decision, is preventing optimal care for TB-patients based on the global TB strategy for elimination. AcknowledgementNone to declare.

Evaluation of real-time PCR assay to detect Schistosoma mansoni infections in a low endemic setting

BackgroundSchistosomiasis constitutes a major public health problem, and 200 million people are estimated to be infected with schistosomiasis worldwide. In Brazil, schistosomiasis has been reported in 19 states, showing areas of high and medium endemicity and a wide range of areas of low endemicity (ALE). Barra Mansa in Rio de Janeiro state has an estimated prevalence of 1%. ALE represent a new challenge for the helminth control because about 75% of infected individuals are asymptomatic and infections occur with a low parasite load (<100 eggs per gram of feces), causing a decrease in sensitivity of stool parasitological techniques, which are a reference for the laboratory diagnosis of this helminth. The objective of this study was to evaluate the performance of a TaqMan quantitative polymerase chain reaction (qPCR) technique in serum and feces DNA samples using the techniques of Kato-Katz (KK), Hoffman, Pons and Janer (HH) as references, during an epidemiological survey using fecal samples and sera from randomized residents from an ALE.MethodsA cross-sectional study conducted from April to December 2011 using a probabilistic sampling that collected 572 fecal and serum samples. The laboratory diagnostic techniques used were: KK, HH and qPCR (feces and serum).ResultsWe obtained the following results using the different diagnostic techniques: KK and HH, 0.9% (n =5); qPCR-feces, 9.6% (n =55); and qPCR-serum, 1.4% (n =8). The qPCR-feces presented the highest positivity, whereas the techniques of HH and KK were the least sensitive to detect infections (0.8%). Compared to HH and KK, qPCR-feces showed a statistically significant difference in positivity (p <0.05), although with poor agreement.ConclusionThe positivity rate presented by the qPCR approach was far higher than that obtained by parasitological techniques. The lack of adequate surveillance in ALE of schistosomiasis indicates a high possibility of these areas being actually of medium and high endemicity. This study presents a control perspective, pointing to the possibility of using combined laboratory tools in the diagnosis of schistosomiasis in ALE.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-014-0558-4) contains supplementary material, which is available to authorized users.

Improved detection of malaria cases in island settings of Vanuatu and Kenya by PCR that targets the Plasmodium mitochondrial cytochrome c oxidase III (cox3) gene

Detection of sub-microscopic parasitemia is crucial for all malaria elimination programs. PCR-based methods have proven to be sensitive, but two rounds of amplification (nested PCR) are often needed to detect the presence of Plasmodium DNA. To simplify the detection process, we designed a nested PCR method whereby only the primary PCR is required for the detection of the four major human Plasmodium species. Primers designed for the detection of the fifth species, Plasmodium knowlesi, were not included in this study due to the absence of appropriate field samples. Compared to the standard 18S rDNA PCR method, our cytochrome c oxidase III (cox3) method detected 10–50% more cases while maintaining high sensitivities (1.00) for all four Plasmodium species in our samples from Vanuatu (n=77) and Kenya (n=76). Improvement in detection efficiency was more substantial for samples with sub-microscopic parasitemia (54%) than those with observable parasitemia (10–16%). Our method will contribute to improved malaria surveillance in low endemicity settings.

Evaluation of the sensitivity of IgG and IgM ELISA in detecting Schistosoma mansoni infections in a low endemicity setting.

Schistosomiasis is a major public health concern, with 200 million people infected worldwide. In Brazil, this disease has been reported in 19 states, and its prevalence in the city of Barra Mansa in Rio de Janeiro State is 1 %. The parasitological diagnostic methods currently available in these areas lack sensitivity; however, enzyme-linked immunosorbent assays (ELISAs) have been employed successfully for the diagnosis of schistosomiasis by using antibodies against antigens of Schistosoma mansoni adult worms and eggs, and for the detection of circulating antigens. The objective of this study was to determine systematically the prevalence of S. mansoni infection in the peripheral areas of Barra Mansa. A cross-sectional study was conducted from April to December 2011 by using probabilistic sampling that collected 610 fecal samples and 612 serum samples. ELISA-IgG with total extracts and ELISA-IgM with trichloroacetic acid-soluble fractions were employed to detect antibodies against S. mansoni and were compared with the Kato-Katz and Hoffman parasitological techniques. Among the individuals studied, anti-S. mansoni antibodies were detected in 11.16 % (n = 71) by ELISA-IgG and in 20.75 % (n = 132) by ELISA-IgM, while the parasitological techniques showed 0.82 % (n = 5) positivity. The agreement between the two ELISA tests was 85.38 % (n = 543), and 8.65 % (n = 55) of the serum samples showed positive results in both tests. The higher positivity of the ELISA-IgM test corroborates the results of previous reports and indicates that the test may be a useful tool in epidemiological studies, particularly in areas of low endemicity for S. mansoni.

Low prevalence of positive interferon-gamma tests in HIV-positive long-term immigrants in Norway

To determine the prevalence and predictors of positive interferon-gamma release assays (IGRAs) and tuberculin skin tests (TSTs) in human immunodeficiency virus (HIV) infected patients in Norway, a low tuberculosis (TB) endemic country. Multicentre cross-sectional study of 298 HIV patients tested with QuantiFERON®-TB Gold In-Tube (QFT-GIT), T-SPOT®.TB (T-SPOT) and TST. A total of 77/298 (26%) QFT-GIT, 29/117 (25%) T-SPOT and 52/217 (24%) TSTs (≥ 5 mm) were positive. The median CD4 count was 427 cells/l. Three QFT-GIT results but no T-SPOT results were indeterminate. Of 52 TST-positive patients, 34 (65%) were QFT-GIT-positive (median interferon-gamma [IFN-] 4.38 international units [IU]/ml), compared to 16% of the TST-negative patients (median INF- 0.81 IU/ml, P < 0.001). Origin from a TB-endemic country, previous active TB and TB exposure were associated with a positive QFT-GIT (P 0.01). Patients from TB-endemic countries living in Norway for ≥ 10 years had lower odds of a positive QFT-GIT (12%; OR 0.17, 95%CI 0.060.53, P 0.002) than patients with 03 years' residence (49%). The prevalence of positive IGRAs in HIV-infected patients was high in this low TB endemic setting. Lower QFT-GIT positivity in long-term residents from TB-endemic countries may reflect a waning of TB-specific immune responses.

Diagnosing schistosomiasis: where are we?

In light of the World Health Organization's initiative to extend schistosomiasis morbidity and mortality control programs by including a disease elimination strategy in low endemic settings, this paper reviews diagnostic tools described during the last decades and provide an overview of ongoing efforts in making an efficient diagnostic tool available worldwide. A literature search on PubMed using the search criteria schistosomiasis and diagnosis within the period from 1978 to 2013 was carried out. Articles with abstract in English and that used laboratory techniques specifically developed for the detection of schistosomiasis in humans were included. Publications were categorized according to the methodology applied (parasitological, immunological, or molecular) and stage of development (in house development, limited field, or large scale field testing). The initial research generated 4,535 publications, of which only 643 met the inclusion criteria. The vast majority (537) of the publications focused on immunological techniques; 81 focused on parasitological diagnosis, and 25 focused on molecular diagnostic methods. Regarding the stage of development, 307 papers referred to in-house development, 202 referred to limited field tests, and 134 referred to large scale field testing. The data obtained show that promising new diagnostic tools, especially for Schistosoma antigen and deoxyribonucleic acid (DNA) detection, which are characterized by high sensitivity and specificity, are being developed. In combination with international funding initiatives these tools may result in a significant step forward in successful disease elimination and surveillance, which is to make efficient tests accessible and its large use self-sustainable for control programs in endemic countries.