A Roadmap for Effective Diagnostics
to Combat Global Infectious Disease
Stefan Bertilsson, Uppsala University, SciLifeLab and Department of Ecology and Genetics, email@example.com
Josef Järhult, Uppsala University Hospital and Uppsala University, Department of Medical Sciences Åsa Melhus, Uppsala University Hospital and Uppsala University, Department of Medical Sciences Eva Molin, Uppsala University, SciLifeLab
Aristidis Moustakas, Uppsala University, Department of Medical Biochemistry and Microbiology
This workshop will deal with the challenges in-volved in developing and then providing rapid, reliable and affordable point-of-care diagnos-tic tools for use in low-resource countries at increased risk from infectious disease threats.
Efficient and sustainable management and prevention of infectious disease, particularly in low-income regions/countries, is critically dependent on access to robust, fast and affordable diagnostics. There is great potential for adopting recent technological advances for practical use in diagnostics and infectious disease monitoring, and there can certainly be huge benefits for health, overall life expectancy and quality of living.
However, there are several obstacles to over-come before diagnostics are effectively imple-mented in healthcare. In this workshop, we will identify major bottlenecks and describe future strategies that we believe will be effective in translating scientific and technological advances into clinical practice.
Questions to be addressed in the workshop are:
- What are the major obstacles to getting rapid, reliable and affordable infection diagnostics on the market and implemented in different healthcare systems?
- How can we accelerate this development to produce emerging diagnostic tools for the future?
- What incentives are there for venture capital and business to invest in this sector and what will be the role of not-for-profit and government-supported stakeholders?
- Who should take responsibility for the different steps to get new infection diagnostics to the market?
A variety of threats demand a variety of solutions
At the global level, infectious disease is one of the leading causes of mortality. As an example, WHO estimates that there were 212 million cases of malaria in 2015 and 429 000 deaths. Respiratory tract infections such as pneumonia, tuberculosis, and viral infections are other ex-amples of infectious diseases which are hard to both control and diagnose and have major nega-tive health impacts. Other infectious diseases of global significance and concern are HIV and sexually transmitted diseases caused by bacteria such as Neisseria gonorrheae and Chlamydia trachomatis. Symptoms of these communicable diseases vary and are sometimes not present. Their consequences can increase and spread with long-term negative impacts on health and life quality. In many regions of the world, diarrhoeal diseases infect billions every year with millions of fatal cases. These disease symptoms can be caused by fundamentally different infectious agents including bacteria, parasites or viruses. Hence, to control and cure the disease, very different treatments and therapeutic practices may be necessary. Apart from improved treatment efficiency, reliable diagnostics are also imperative in order to avoid over-prescription of drugs causing resistance development, e.g. to antibiotics as well as unnecessary adversary side effects. It is clear that for many of the most globally significant infectious diseases, fast and precise diagnostics will be the first and critically important factor for effective treatment and to limit the spread of the disease.
A disproportionate global health burden
Infectious disease is a global area of concern, but the negative effects of infectious disease on human health, wellbeing and life expectancy (i.e. disease burden) is not equally distributed across the global human population. Poor sanitary conditions, overall low education levels, failing infrastructure and limited resources for treating disease conditions make developing countries and low-income regions particularly at risk and exposed to infectious disease threats. There is also a demographic component with young chil-dren and infants being disproportionately affected. All diseases discussed above are an especially heavy healthcare burden in developing countries, and most of them take their primary death toll in children under five.
Rapid technological advances in infectious disease diagnostics
The field of infectious disease diagnostics has experienced a rapid transition and technological change over the past few years. Scientific advances in developing molecular recognition tools, finding and validating biomarkers of disease and provision of affordable and fast-sequencing technologies have opened exciting new opportunities for diagnostics that are considerably faster, more precise and informative compared to the traditional microscopy or cultivation-based methods that have been the golden standard since the birth of infection biology as a research field. The benefits could be major and a pertinent example is tuberculosis where microscopic examination of sputum is cheap, fast and unspecific, and cultures are resource-demanding and may require up to 6 weeks to get the first results and highly specific. Using nucleic acid amplification methods, results can be obtained within a day along with information on drug resistance and sensitivity that may guide further treatments and measures to prevent further spread of the disease.
Inadequate infrastructure and high costs restrict use in developing countries
So this is very good news, at least for some parts of the world. Developing countries and low- income regions invariably cannot provide the infra structure required to take advantage of most of these technological advances, nor can they afford to invest in the costly instrumentation or diagnostic kits that are often needed. Sequencing and PCR-based diagnostics are already in use for detecting and describing infectious disease agents and finding the appropriate treatment to most efficiently control and cure the disease, but such technologies rely on moderately to very expensive instrumentation such as thermocyclers and DNA sequencers with ancillary equipment. Even if such investments can be made, stable electricity for instrument performance and distribution networks and refrigeration for storage of reagents, along with considerable training, are required to make it work. It would be unrealistic to expect such diagnostics to be broadly adopted across resource-poor regions around the world. Inadequate infrastructure will probably also prevent broader centralized use of core facilities to serve a country or a region. How should samples be transported to the laboratories? Will it be possible or even desirable that sick individuals travel for diagnostics at a central hospital or core facility? How will the patient then be informed of the result from the diagnostic test and how long will this entire process take?
Advantages of point-of-care approaches in resource-poor settings
Point-of-care approaches have been identified as a more promising strategy for infectious disease diagnostics, management and control in the developing world. Such strategies could open the possibility to meet the patient in their local area or perhaps even in their home and offer simple and robust diagnostic tests that produce rapid results, enabling near immediate action to be taken to avoid spreading the disease, to cure it or to treat the symptoms. Appropriate point-of-care diagnostic tests should ideally adhere to the ASSURED criteria developed by the World Health Organization (Box 1). This would rule out both sequencing and essentially also all PCR-based diagnostics for putative point-of-care diagnostics. Instead, affordable and robust miniaturized assays based on affinity-detection of either antigens associated with the infectious agent or human biomarkers of disease have been the methods of choice.
Lateral flow immunoassays (LFIA) is the most widespread platform for such diagnostics and is based on binding of a specific antibody to an infectious disease antigen and by incorporating a reporter molecule that can be visibly inspected, readout can be done within minutes. The technical requirements and need for training are minimal with the home pregnancy test being the best-known example. There are many examples of such diagnostic tests for microbial infections (HIV, hepatitis, malaria, cryptococcal meningitis, etc.) but one potential bottleneck is the need to obtain samples that are reasonably clean and with high concentration of the respective analytes (disease antigens). If testing is done with samples that feature low levels of the analyte, this may result in false negatives, thus violating the ASSURED principles. Because of these and other limitations, there is much ongoing research to develop more sensitive and versatile (with regards to sample type) diagnostic tests. One promising avenue in this regard is the miniaturization of nucleic acid-based assays in microfluidic devices that should be low-cost and able to operate without expensive equipment and stable electrical supply. But who should safeguard and support the continued efforts and work in such research and development endeavours?
“Globally important” pathogens get priority
Although point-of-care diagnostics have received a lot of attention recently, we are still far from a solution to meet the diagnostic challenges in combatting global infectious disease. Development of functional diagnostic tools is typically very resource-demanding and the monetary return on investment is highly uncertain or sometimes even predictably low. This may prevent industry and venture capital from investing in bringing such technologies to market even if the discoveries have been made. Who should fund the early (pre-clinical) development of diagnostics tools and who should take them to market? Some of the more pertinent examples of the successful development and use of diagnostics for infectious disease, also in the developing world, are for malaria, HIV or disease caused by other “globally important” pathogens. The worldwide number of infected individuals and the occasion-al spread and outbreaks in more developed and high-income regions make these diseases relevant targets and accordingly considerable efforts are spent on developing diagnostic tools. There are, however, a large number of lesser known, often regionally limited but still very severe infectious diseases that will not get the same attention, and where prospects of having diagnostic tools developed are less positive. Trypanosomiasis and Leichmaniasis are examples of two such tropical diseases. Who should develop diagnostic tests for infectious diseases where those affected are mainly from poor rural communities? Similar to HIV and malaria, infections of the respiratory and gastrointestinal tracts are global health problems where diagnostics are clearly lagging behind. Such infections cause much suffering and death (particularly among children) in both developing countries and more resource-rich parts of the world. The challenges in providing access to rapid and precise point-of-care infectious disease diagnostics are shared and this may provide a window of opportunity. If we can solve these problems in our own backyard, we can also (in the process) improve the situation for the rest of the world.
Adapting new diagnostic tools to local conditions
Even when a diagnostic tool suitable for point of care according to the ASSURED criteria is available, it may not always be adopted by local health care providers or the population at risk. There could be cultural resistance and conflict with prevailing traditions or beliefs, or there may simply be inertia in adopting new technology. The costs may also be too high and there may be challenges with distribution to the users related to limitations in transport and freight infrastructure. Thus, in addition to the new technologies and methodologies themselves, it is imperative that education, knowledge and in-formation are developed in accordance with the local social and cultural context, in close collaboration with key actors in the target regions.
This begs the question: where does the responsibility lie and who should take action? Training and education is one aspect in this, as is legislation, politics and religion. By discussing and establishing the responsibilities and roles of different stakeholders, we hope that this workshop will pave the way for more efficient infectious disease diagnostics for the benefit of humankind (Figure 1).
Identifying the bottlenecks and accelerating progress
The main outcome of the workshop will be the shared experiences, ideas and visions of the participants to stimulate the development of effective and useful diagnostic tools for infectious disease. By participants then bringing the information back to national governments, NGOs, regional health sectors, knowledge-based organizations such as universities and research institutes, funding bodies and industry, we will move beyond the current situation and make a difference. At the end of the workshop, we hope to not only have identified some of the major bottlenecks, but also have solutions for how to accelerate the development and implementation. The obstacles will in part be technical, as well as cultural, legislative and economical. Incentives for investments as well as the role of not-for-profit and governmental organizations will be discussed with a hope of reaching consensus and creative solutions for how to move forward.
- Jack, A. 2015. Affordable diagnostics is the missing link in medicine. Financial Times.
- Howitt, P., Darzi, A., Yang, G.-Z., et al. 2012. Technologies for global health. The Lancet. 380:507-535.
- Urdea, M., Penny, L.A., Olmsted, S.S., et al. 2006. Require-ments for high impact diagnostics in the developing world. Nature Supplements: Improved Diagnostic Tech-nologies for the Developing World. p73-79. doi:10.1038/nature05448
- Kozel, T.R. Burnham-Marusich, A.R. 2017. Point of care testing for infectious disease – Past, present and future. Journal of Clinical Microbiology. In Press. doi:10.1128/JCM.00476-17.
- Yager, P., Domingo, G.J., Gerdes. J. 2008. Point-of-care diagnostics for global health. Annual Reviews in Biomedical Engineering. 10:107-144. doi:10.1146/annurev.bio-eng.10.061807.160524.
- Peeling, R.W., Mabey, D. 2010. Point-of-care tests for diagnosing infections in the developing world. Clinical Microbiology and Infectious Disease. 16:1062-1069.
Characteristics of suitable diagnostic tests for developing countries (ASSURED) developed by the World Health Organization.
- Affordable by those at risk of infection
- Sensitive (few false negatives)
- Specific (few false positives)
- User-friendly (simple also for non-trained
- Rapid to enable treatment at first visit and no need for special storage, and Robust
- Equipment-free (not relying on electricity)
- Deliverable to those who need it (portable)