Improved water-disinfecting solar-powered bottle by students gets $40,000 prize

University of Washington engineering students have won an international contest for their design to monitor water disinfection using the sun's rays. The students will share a $40,000 prize from the Rockefeller Foundation and are now working with nonprofits to turn their concept into a reality.

Team member Jacqueline Linnes, who recently completed her bioengineering doctorate, traveled to Bolivia last year with the UW chapter of Engineers Without Borders. While there, she and other students treated their drinking water by leaving it in plastic bottles in the sun.

The concept is an old one. Solar disinfection of water in plastic bottles, also called SODIS, is promoted by many nonprofits. It offers a cheap and easy way to reduce some of the roughly 1.5 million diarrhea-related children's deaths each year. But global adoption has been slow, partly because it is hard to know when the water is safe to drink.

The UW entered a competition to design an indicator for Fundación SODIS, a Bolivia-based nonprofit dedicated to testing and promoting this method. Solar disinfection in water bottles removes more than 99.9 percent of bacteria and viruses, with results similar to chlorination.

The UW device lets users know when the sun's rays have done their job.

Computer models show malaria-infected RBCs stiffen, restrict capillary flow

A team of researchers at Brown University and the Massachusetts Institute of Technology has completed the first modeling, followed by experiments, of how red blood cells are infected by a malarial parasite that attacks the brain. The researchers report that infected cells stiffen by as much as 50 times more than healthy cells. Infected cells also tend to stick along blood vessel walls, impeding the flow of blood to critical organs. Results appear in the early online edition of the Proceedings of the National Academy of Sciences.

Although the incidence of malaria has declined in all but a few countries worldwide, according to a World Health Organization report earlier this month, malaria remains a global threat. Nearly 800,000 people succumbed to the mosquito-borne disease in 2009, nearly all of them in the developing world.

Physicians do not have reliable treatment for the virus at various stages, largely because no one has been able to document the malaria parasite’s journeys in the body.

Now researchers at Brown University and the Massachusetts Institute of Technology have used advanced computer modeling and laboratory experiments to show how malaria parasites change red blood cells and how the infected cells impede blood flow to the brain and other critical organs.

WHO plans to integrate world's traditional medicine in one database

Yojana Sharma of SciDev.net reports on the WHO initiative to set up a global database of traditional medicines, due in 2011.

The first global database documenting the effectiveness of traditional medicines, which are widely used as the first source of healthcare around the world, has been announced by the WHO.

The International Classification of Traditional Medicine will be set up in the first half of next year to document traditional medicines and, for the first time, provide effectiveness data based on common standards.

"A number of countries have databases on traditional medicine, but because there have been no international standards until now, the data could not be compared," said Molly Meri Robinson Nichol, a technical officer at the WHO. "Western medicine has a vast database on diseases, but we do not have that information on traditional medicine, which makes it impossible to make a statement on its effectiveness."

Recent review of African health research reveals gaps, opportunities

The McLaughlin-Rotman Center for Global Health has published a series of open-access papers that paints a detailed picture of the state of health innovation research in Africa (link to BiomedCentral International Health and Human Rights, December 2010). Dr. Peter Singer and Dr. Ken Simiyu share their research findings in this engaging studio discussion.

African Innovation: New Hope for Local Health Issues

Key findings of the group include issues in the stagnation of viable technologies, such as diagnostic tests, medical devices, and plant medicine due to lack of commercialization.

Other barriers in bringing these important innovation to the people include lack of infrastructure and scientific equipment, lack of capital financing and enterpreneurship, and inappropriate regulation and policies.

Suggestions to improve these issues comprise the need for a viable innovation network between scientists and entrepreneurs, addition of some modest funds to continue and validate the research, and addressing the gap in research infrastructure and scientific equipment.

These models parallel the situation of health research in Southeast Asia, where similar opportunities and challenges exist for health innovation. These investable ideas, if properly channeled, stand to make a huge difference in the people of Africa and Southeast Asia in the future. It is envisioned for these countries to develop health research so that they can create local products, grow local industries for health products, and provide solutions to local health needs of today.

Reference: McLaughlin-Rotman Center for Global Health. (2010, December). African Innovation: New Hope for Local Health Issues. Accessed December 2010. Retrieved from http://www.mrcglobal.org/projects/african_innovation.

Higher Actual Dengue Incidence Numbers in Cambodia than in National Reports, 2006–2008

Dengue vaccines are now in late-stage development, and evaluation and robust estimates of dengue disease burden are needed to facilitate further development and introduction. In Cambodia, the national dengue case-definition only allows reporting of children less than 16 years of age, and little is known about dengue burden in rural areas and among older persons. To estimate the true burden of dengue in the largest province of Cambodia, Kampong Cham, we conducted community-based active dengue fever surveillance among the 0-to-19–year age group in rural villages and urban areas during 2006–2008.


General Findings

The large-scale active surveillance study for dengue fever in Cambodia found a higher disease incidence than reported to the national surveillance system, particularly in preschool children and that disease incidence was high in both rural and urban areas. It also confirmed the previously observed focal nature of dengue virus transmission.

Small tech with big promise for healthcare

Nanotechnology should not suffer the same fate as GM — potential health and environmental hazards should be monitored and regulated early on. David Dickson, director of SciDev.Net, discusses the promise of nanomaterials. 

If a new and potentially hazardous field of technological innovation is to flourish in a social environment,  two factors are essential, even if the hazards are still relatively speculative.

The first is a clear demonstration of its value to individual welfare, creating a demand for what it promises.

The second is evidence that the potential dangers can be adequately monitored, and regulations put in place to minimise the chance that harmful effects will occur.

Nanotechnology for health: Facts and figures

Can developing countries use nanotechnology to improve health? Priya Shetty looks at nanomedicine's promise at a SciDev report.

Nanotechnology — the science of the extremely small — holds enormous potential for healthcare, from delivering drugs more effectively, diagnosing diseases more rapidly and sensitively, and delivering vaccines via aerosols and patches.

Nanotechnology is the science of materials at the molecular or subatomic level. It involves manipulation of particles smaller than 100 nanometres (one nanometre is one-billionth of a metre) and the technology involves developing materials or devices within that size — invisible to the human eye and often many hundred times thinner than the width of human hair. The physics and chemistry of materials are radically different when reduced to the nanoscale; they have different strengths, conductivity and reactivity, and exploiting this could revolutionise medicine.

For example, a major challenge of modern medicine is that the body doesn't absorb the entire drug dose given to a patient. Using nanotechnology, scientists can ensure drugs are delivered to specific areas in the body with greater precision, and the drugs can be formulated so that the active ingredient better permeates cell membranes, reducing the required dose.

Boston University researchers create novel rapid biosensor

The portable detector platform, comprising plasmonic nanohole arrays (PNAs), can be adapated for hospitals, malls, and airports

A team of researchers headed by Hatice Altug (ECE) and John Connor (Microbiology) has developed a novel biosensor that directly detects live viruses from biological samples even without sample preparation. They have reported on this breakthrough in the November 5 online edition of Nano Letters.


The biosensor comprises plasmonic nanohole arrays (PNAs), or arrays of apertures with diameters of about 250 to 350 nanometers on metallic films, that transmit light more strongly at certain wavelengths.

A live virus (e.g., Ebola, monkeypox, or smallpox virus) in blood or serum, for example, can bind to the sensor surface. A change in the effective refractive index in the close vicinity of the sensor will shift the resonance frequency of the light transmitted through the PNAs. The degree of this shift reveals the presence and the concentration of the virus in the solution.

Symposium aims to place health systems as cornerstone in health research

The First Global Symposium on Health Systems Research, organized by the WHO this week (16–19 November) in Montreux, Switzerland, aims to foster international studies on health systems. T.V. Padma reports on SciDev.Net.

The First Global Symposium on Health Systems Research is expected to establish health systems research as a "third pole" of health research, alongside biomedical and clinical research.

Research on how to improve health delivery and health outcomes has long been neglected and must be put on researchers' agendas, a WHO expert has said ahead of the first global meeting on such research.

Tim Evans, WHO's outgoing assistant director general for information, evidence and research, told SciDev.Net that scientific research is needed to ensure that everyone benefits from healthcare delivery.

The symposium aims to dispel the idea that healthcare delivery is a 'common sense' problem unrelated to high-quality science, said Evans, who chairs the meeting's steering committee.

The meeting is expected to be "a watershed" in sharing evidence on how to use science to accelerate health coverage, he added.

Over 1,300 researchers from 100 countries will gather to provide evidence-based information to policymakers on how to expand the reach of healthcare systems in developing countries.

WHO endorses MODS, NRI and CRI to assess TB in resource-limited settings

In a policy statement by the World Health Organization on July 2010, MODS, CRI, and NRA assays have been given the vote of confidence by the international agency for use by laboratory officials and health care providers for diagnosis of MDR-TB (multi-drug resistant tuberculosis) cases.

Colorimetric redox indicator (CRI) methods comprise growing Mycobacterium tuberculosis isolates in conventional culture. A microscopically observed drug susceptibility (MODS) assay comprises observing micro-colony growth and typical cord-formation of M. tuberculosis in sealed microtitre plates containing liquid culture medium, through an inverted microscope. Nitrate reductase assay (NRA), on the other hand, involves a direct test on smear-positive sputum specimens and an indirect test on M. tuberculosis isolates grown from conventional solid culture.

All three methods exhibit high specificity and sensitivity. These criteria, among others, have led the WHO to recommend the use of selected non-commercial culture and DST methods as an interim solution in resource-constrained settings, under clearly defined programmatic and operational conditions, while capacity for genotypic and/or automated liquid culture and DST are still being developed.



Reference: World Health Organization. 2010, July. Non-Commercial Culture And Drug-Susceptibility Testing Methods For Screening Of Patients At Risk Of Multi-Drug Resistant Tuberculosis: Policy Statement. Retrieved November 15, 2010. Accessed at http://www.who.int/tb/dots/laboratory/whopolicy_noncommercialculture_and_dstmethods_july10.pdf.

Mixed success in science for developing world, says UNESCO

Developing countries more than doubled their output of scientific publications between 2002 and 2008, but their share of patent applications remained extremely low. Mico Tatalovic reports on SciDev.Net.

The developing world's share of science publications rose from a fifth to nearly a third during this time, according to the 'UNESCO Science Report 2010: Current Status of Science around the World'.

The report, published today (10 November), assessed the number of publications recorded in Thomson Reuters' Science Citation Index between 2002 and 2008, during which the total number of global science publications increased by around 35 per cent.

Much of the increase in the developing world is because of the growth of Brazil, China and India. The report found that least developed countries (LDCs), a subset of developing countries, have also increased their publications output — by 80 per cent. But this is from the starting point of 2,000 papers a year, compared with the total developing country output of 165,000 papers, and thus represents only 0.4 per cent of the world's total output.

Why has the Global Forum for Health Research collapsed?

Poor countries striving to improve their health systems deserve better than the unexplained implosion of the Global Forum for Health Research. Beverly Peterson Stearns reports on SciDev.Net.

Barely a year ago nearly 1,000 people from 80 countries gathered enthusiastically at the Palacio de Convenciones in Havana, Cuba, under the banner 'Innovating for the health of all'. More than half came from low- and middle-income countries. They were attending the annual meeting  of the non-profit organisation the Global Forum for Health Research (GFHR), eager to hear about inventive and effective ways to conduct research, and urgently seeking to improve health in their countries.

Now, less than a year after taking office, the forum's executive director, Anthony Mbewu, has resigned, and the forum itself is in failing health. The prognosis is poor. Very few remain in its Geneva secretariat. Many employees have quit, been fired, or have retired early.

Time for explanations

Why did this international organisation, set up in 1998, founder so spectacularly and so quickly when the need for health research remains so great? More importantly, what now are the prospects for ordinary people in developing countries? They pinned their hopes on local leaders in health and research who, in turn, sought guidance from experts at the annual forums.

South Africa's Sunday Times, which reported Mbewu's resignation on 31 October, said that his appointment as head of the forum had drawn criticism from HIV/AIDS activists. They had charged Mbewu, the former president of South Africa's Medical Research Council, with supporting the Mbeki government's denial of HIV and AIDS.

But in Havana the controversy was largely unrecognised. Mbewu responded to a reporter's question about the criticisms saying, "I'm a researcher, not an activist." At the time, that seemed a sufficient answer for his fellow health researchers too. They seemed satisfied that Mbewu's appointment by the forum — a respected organisation originally set up under the auspices of the WHO — meant his qualifications had been well-vetted.

A year on, many of the health leaders and researchers who gathered in Havana will convene in Montreux, Switzerland, at the First Global Symposium on Health Systems Research (16–19 November).  Will any of them probe the GFHR's collapse — or will they politely not mention it?

The Foundation Council, the forum's policy- and decision-making body, should bear responsibility for explaining what has happened to this small but once-vibrant organisation, to which so many from developing countries looked for guidance. But the responsibility is not theirs alone. The entire health research community has a duty to not turn a blind eye to the forum's failure.

A betrayal of trust?

I was in Havana as a freelance writer drafting a report on that meeting, similar to others I wrote for the Forum about  previous meetings in Mexico City (2004), Mumbai (2005), Cairo, (2006), Beijing (2007) and Bamako (2008). The great strength of these annual meetings was making well-known health researchers, public health experts, economists and innovators accessible to the people who need their help the most.

The meetings were moved each year to a new venue. That allowed field workers, students, community physicians and academics in some of the world's poorest countries to attend. There were a few large plenary sessions and many small group sessions that encouraged interaction. Even people without computers could be part of this network.

Impressive young people from poor countries sat in discussion groups next to rich entrepreneurs, respected academics and government decision-makers, all talking about problems held in common. I listened with growing optimism that progress in global health could come through collaboration that reached across the divides of poverty, borders, and politics.

The meetings' official programmes highlighted the Millennium Development Goals; combating disease and poverty; equitable access; capacity building and health systems; and innovation.

But discussions ranged much further and deeper, covering subjects some countries would rather not have highlighted: an obesity epidemic in Mexico, crushing poverty in India, female genital mutilation in Egypt, HIV/AIDS in China, counterfeit drugs in Africa, and embargoes and naturopathic medicines in Cuba. Each annual meeting was, in the fullest sense of the word, a forum.

I was astonished by how quickly and quietly the health of the GFAR deteriorated.  I heard reports as the staff diminished.  I read that employees were bringing lawsuits alleging unfair dismissal.  Gill Samuels, chair of the forum's 20-member foundation council, confirmed in an email to me that Mbewu had resigned. But she denied that there are legal cases pending. "Nothing else to add at the moment," she wrote in answer to my query.

Nothing to add? I hope there will soon be a considerable amount to add. Samuels, who comes from the pharmaceutical industry, and the others who sit on the council and come from foundations, universities, governments and institutes, are responsible for appointing the director and overseeing the forum's budget and plan of action.

Their explanations — or lack of them — will affect the credibility not only of the forum, but of any existing or future organisation seeking the trust of researchers and of those depending on them.

Beverly Peterson Stearns is a freelance writer and author. She lives in the United States.


Reference: Stearns, B. 2010. Why has the Global Forum for Health Research collapsed? Retrieved November 15, 2010. Accessed at SciDev.Net's website at: http://www.scidev.net/en/opinions/why-has-the-global-forum-for-health-research-collapsed-.html.

AIDS Vaccine for Asia Network (AVAN): Expanding the Regional Role in Developing HIV Vaccines

Kent SJ, Cooper DA, Chhi Vun M, Shao Y, Zhang L, et al. (2010) AIDS Vaccine for Asia Network (AVAN): Expanding the Regional Role in Developing HIV Vaccines. PLoS Med 7(9): e1000331. doi:10.1371/journal.pmed.1000331


The HIV/AIDS pandemic continues to spread and an AIDS vaccine is urgently needed. While facing unprecedented challenges, AIDS vaccine development activities are continuing around the globe. Recent results of the Thai Phase III vaccine trial are renewing such efforts. In accordance with the goals of the Global HIV Vaccine Enterprise, there is now clear recognition of the role that regional alliances can play in fostering and facilitating AIDS vaccine development, and there is broad agreement that international collaborations are the most effective way forward to develop and evaluate the next generation of AIDS vaccine candidates.

In response to these challenges, the Asian region has recently formed the AIDS Vaccine for Asia Network (AVAN).

AVAN has been initiated to meet these needs and actively facilitate the development of a regional AIDS vaccine strategy that accelerates research and development of an AIDS vaccine through government advocacy, improved coordination and harmonization of research; develops clinical trial and manufacturing capacity; supports ethical and regulatory frameworks; and ensures community participation.

Scripps researchers develop new detection test for river blindness parasite

Innovation will help eliminate tropical malady

In a press release by the Scripps Research Institute in La Jolla, california, the institute announced that its scientists have developed the first screening method that rapidly identifies individuals with active river blindness, a parasitic disease that afflicts an estimated 37 million people. The test could change the current strategy of mass treatment in areas where river blindness, also known as onchocerciasis, is suspected.

The study was published online on October 5, 2010, by the journal PLOS Neglected Tropical Diseases.

"A sensitive and reproducible diagnostic test for this disease is crucial for the success of worldwide control and elimination programs," said Kim Janda, Ph.D., a professor in the Departments of Chemistry and Immunology and Microbial Science, member of The Skaggs Institute for Chemical Biology, and director of The Worm Institute for Research and Medicine (WIRM) at Scripps Research. "This diagnostic tool could be a game-changer for how the disease will be treated in the future."

Judith Denery, Ph.D., a senior research associate in the Janda laboratory and the paper's first author, adds, "Because current tests often give false negatives, they are unreliable indicators of infection. For organizations such as the World Health Organization and others working to eliminate the disease, this lack of accuracy is frustrating, time-consuming, and costly."

Enhanced Detection, Diagnosis of Leishmaniasis in Bangladesh

Mondal D, Nasrin KN, Huda MM, Kabir M, Hossain MS, et al. (2010) Enhanced Case Detection and Improved Diagnosis of PKDL in a Kala-azar-Endemic Area of Bangladesh. PLoS Negl Trop Dis 4(10): e832. doi:10.1371/journal.pntd.0000832

To support the Bangladesh National Kala-azar Elimination Programme (NKEP), the group investigated the feasibility of using trained village volunteers for detecting post-kala-azar dermal leishmaniasis (PKDL) cases, using polymerase chain reaction (PCR) for confirmation of diagnosis and treatment compliance by PKDL patients in Kanthal union of Trishal sub-district, Mymensingh, Bangladesh.

Methods
In this cross-sectional study, Field Research Assistants (FRAs) conducted census in the study area, and the research team trained village volunteers on how to look for PKDL suspects. The trained village volunteers (TVVs) visited each household in the study area for PKDL suspects and referred the suspected PKDL cases to the study clinic. The suspected cases underwent physical examinations by a qualified doctor and rK39 strip testing by the FRAs and, if positive, slit skin examination (SSE), culture, and PCR of skin specimens and peripheral buffy coat were done. Those with evidence of Leishmania donovani (LD) were referred for treatment. All the cases were followed for one year.

Results
The total population of the study area was 29,226 from 6,566 households. The TVVs referred 52 PKDL suspects. Probable PKDL was diagnosed in 18 of the 52 PKDL suspect cases, and PKDL was confirmed in 9 of the 18 probable PKDL cases. The prevalence of probable PKDL was 6.2 per 10,000 people in the study area. Thirteen PKDL suspects self-reported from outside the study area, and probable and confirmed PKDL was diagnosed in 10 of the 13 suspects and in 5 of 10 probable PKDL cases respectively. All probable PKDL cases had hypopigmented macules. The median time for PKDL development was 36 months (IQR, 24–48). Evidence of the LD parasite was documented by SSE and PCR in 3.6% and 64.3% of the cases, respectively. PCR positivity was associated with gender and severity of disease. Those who were untreated had an increased risk (odds ratio = 3.33, 95%CI 1.29–8.59) of having persistent skin lesions compared to those who were treated. Patients' treatment-seeking behavior and treatment compliance were poor.

Conclusion
Improved detection of PKDL cases by TVVs is feasible and useful. The NKEP should promote PCR for the diagnosis of PKDL and should find ways for improving treatment compliance by patients.

External Quality Control Assessment for the Molecular Diagnosis of Dengue Infections

Domingo C, Niedrig M, Teichmann A, Kaiser M, Rumer L, et al. (2010) 2nd International External Quality Control Assessment for the Molecular Diagnosis of Dengue Infections. PLoS Negl Trop Dis 4(10): e833. doi:10.1371/journal.pntd.0000833

Currently dengue viruses (DENV) pose an increasing threat to over 2.5 billion people in over 100 tropical and sub-tropical countries worldwide. International air travel is facilitating rapid global movement of DENV, increasing the risk of severe dengue epidemics by introducing different serotypes. Accurate diagnosis is critical for early initiation of preventive measures. Different reverse transcriptase PCR (RT-PCR) methods are available, which should be evaluated and standardized. Epidemiological and laboratory-based surveillance is required to monitor and guide dengue prevention and control programmes, i.e., by mosquito control or possible vaccination (as soon as an effective and safe vaccine becomes available).

Objective

The purpose of the external quality assurance (EQA) study described is to assess the efficiency and accuracy of dengue molecular diagnosis methods applied by expert laboratories.

Study Design

A panel of 12 human plasma samples was distributed and tested for DENV-specific RNA. The panel comprised 9 samples spiked with different DENV serotypes (DENV-1 to DENV-4), including 10-fold dilution series of DENV-1 and DENV-3. Two specificity controls consisted of a sample with a pool of 4 other flaviviruses and a sample with chikungunya virus. A negative control sample was also included.

Results

Thirty-seven laboratories (from Europe, Middle East Asia, Asia, the Americas/Caribbean, and Africa) participated in this EQA study, and reports including 46 sets of results were returned. Performance among laboratories varied according to methodologies used. Only 5 (10.9%) data sets met all criteria with optimal performance, and 4 (8.7%) with acceptable performance, while 37 (80.4%) reported results showed the need for improvement regarding accomplishment of dengue molecular diagnosis. Failures were mainly due to lack of sensitivity and the presence of false positives.

Conclusions

The EQA provides information on each laboratory's efficacy of RT-PCR techniques for dengue diagnosis and indicates for most laboratories an urgent need to improve sensitivity and specificity.

New dermal patch delivers influenza vaccine for needle phobics

PVP microneedles confer better immunity compared to intramuscular injections in mice.

Researchers from Emory University in Atlanta, Georgia have developed a new method for influenza prophylaxis, published in Nature Medicine [1].

Sullivan et al. has fabricated plastic microneedles made of polyvinylpyrrolidone (PVP) to encapsulate a dried form of inactivated influenza virus. The microneedles penetrate the skin up to the portion of the dermis where antigen-presenting cells are present, and where PVP encapsulation dissolves and releases the influenza vaccine.

New incentives offered for solutions to current biomedical challenges

Innocentive, an open innovation company, has opened up new challenges in the field of biomedicine on its website. Among them are to find:

• urinary biomarkers for lupus nephritis
• novel therapeutic concepts to treat cancer
• novel detection technologies for cellular metabolites
• non-destructive delivery of macromolecules to live tissues
• predictive models for segmentation of populations (for applications in clinical trials for drug development)

• strategies to maintain fully differentiated human primary renal proximal tubular epithelial cells
• strategies for differentiation of renal proximal tubular cells from hES or hiPS cells

If you or your laboratory are planning or currently working on brilliant solutions to these challenges, you have a big chance to win 10,000-50,000 US dollars, or even up to 1,000,000 US dollars.

Influence of Age, Sex, Ethnicity and IgE on Human Exposure and Immunity to Schistosomiasis Infections

Pinot de Moira A, Fulford AJC, Kabatereine NB, Ouma JH, Booth M, et al. (2010) Analysis of Complex Patterns of Human Exposure and Immunity to Schistosomiasis mansoni: The Influence of Age, Sex, Ethnicity and IgE. PLoS Negl Trop Dis 4(9): e820. doi:10.1371/journal.pntd.0000820

Numerous factors may influence Schistosoma infection intensity and prevalence within endemic communities, including exposure-related factors such as local environment and behaviour, and factors relating to susceptibility to infection such as immunology and genetics. While animal studies performed in the laboratory can be tightly controlled, human populations are highly heterogeneous, varying according to demographic characteristics, genetic background and exposure to infection. The heterogeneous nature of human water contact behaviour in particular makes it difficult to distinguish between a lack of cercarial exposure and reduced susceptibility to infection as the cause for low levels of infection in the field.

Methods and Principal Findings

In this study we investigate risk factors for Schistosoma mansoni infection in a rural Ugandan fishing community receiving treatment as part of a multi-disciplinary longitudinal reinfection study. More specifically, we examine the influence that age, sex and ethnic background have on susceptibility to reinfection after anti-helminth drug treatment, but use individual estimates of cercarial exposure and multivariable methods in an attempt to remove noise created by environmental and behavioural heterogeneities. We then investigate whether schistosome-specific IgE immune responses could account for any remaining variations in susceptibility to reinfection. Our findings suggest that observed ethnic- and sex-related variations in S. mansoni reinfection were due to variations in cercarial exposure, as opposed to biological differences in susceptibility to infection. Age-related differences in reinfection were not explained by exposure, however, and appeared linked to the balance of IgE and IgG4 to the tegumental antigen SmTAL1 (formerly Sm22.6), which itself was significantly related to resistance to reinfection.

Conclusions

This study highlights the benefit of taking a multidisciplinary approach in complex field settings; it allows the ecology of a population to be understood and thus more robust conclusions to be made.

Material reposted under the Creative Commons License.

Multi-Country Evaluation of Two Commercial Dengue Diagnostic Kits

Guzman MG, Jaenisch T, Gaczkowski R, Ty Hang VT, Sekaran SD, et al. (2010) Multi-Country Evaluation of the Sensitivity and Specificity of Two Commercially-Available NS1 ELISA Assays for Dengue Diagnosis. PLoS Negl Trop Dis 4(8): e811. doi:10.1371/journal.pntd.0000811

Early diagnosis of dengue can assist patient triage and management and prevent unnecessary treatments and interventions. Commercially available assays that detect the dengue virus protein NS1 in the plasma/serum of patients offers the possibility of early and rapid diagnosis.

Methodology/Principal Findings

The sensitivity and specificity of the Pan-E Dengue Early ELISA and the Platelia™ Dengue NS1 Ag assays were compared against a reference diagnosis in 1385 patients in 6 countries in Asia and the Americas. Platelia was more sensitive (66%) than Pan-E (52%) in confirmed dengue cases. Sensitivity varied by geographic region, with both assays generally being more sensitive in patients from SE Asia than the Americas. Both kits were more sensitive for specimens collected within the first few days of illness onset relative to later time points. Pan-E and Platelia were both 100% specific in febrile patients without evidence of acute dengue. In patients with other confirmed diagnoses and healthy blood donors, Platelia was more specific (100%) than Pan-E (90%). For Platelia, when either the NS1 test or the IgM test on the acute sample was positive, the sensitivity versus the reference result was 82% in samples collected in the first four days of fever. NS1 sensitivity was not associated to disease severity (DF or DHF) in the Platelia test, whereas a trend for higher sensitivity in DHF cases was seen in the Pan-E test (however combined with lower overall sensitivity).

Conclusions/Significance

Collectively, this multi-country study suggests that the best performing NS1 assay (Platelia) had moderate sensitivity (median 64%, range 34–76%) and high specificity (100%) for the diagnosis of dengue. The poor sensitivity of the evaluated assays in some geographical regions suggests further assessments are needed. The combination of NS1 and IgM detection in samples collected in the first few days of fever increased the overall dengue diagnostic sensitivity.


Material reposted under the Creative Commons License.