Comparative performance study of three Ebola rapid diagnostic tests in Guinea.

BACKGROUND: The 2014/15 Ebola outbreak in West Africa resulted in 11,000 deaths and massive strain on local health systems, and the ongoing outbreak in Democratic Republic of Congo has afflicted more than 3000 people. Accurate, rapid Ebola diagnostics suitable for field deployment would enable prompt identification and effective response to future outbreaks, yet remain largely unavailable. The purpose of this study was to assess the accuracy of three novel rapid diagnostic tests (RDTs): an Ebola, an Ebola-Malaria, and a Fever Panel test that includes Ebola, all from a single manufacturer. METHODS: We evaluated the three RDTs in 109 Ebola-positive and 96 Ebola-negative stored serum samples collected during the outbreak in Guinea in 2014/15, and tested by real-time polymerase chain reaction (RT-PCR). Sensitivity, specificity, and overall percent agreement were calculated for each RDT using RT-PCR as a reference standard, stratified by Ct value ranges. RESULTS: All tests performed with high accuracy on samples with low Ct value (high viral load). The Fever Panel test performed with the highest accuracy, with a sensitivity of 89.9% and specificity of 90.6%. The Ebola and Ebola-Malaria tests performed comparably to each other: sensitivity was 77.1 and 78% respectively, and specificity was 91.7% for the Ebola test and 95.8% for the Ebola-Malaria test. CONCLUSIONS: This study evaluated the accuracy of three novel rapid diagnostic tests for Ebola. The tests may have significant public health relevance, particularly the Fever Panel test, which detects seven pathogens including Ebola. Given limitations to the study resulting from uncertain sample quality, further evaluation is warranted. All tests performed with highest accuracy on samples with low Ct value (high viral load), and the data presented here suggests that these RDTs may be useful for point-of-care diagnosis of cases in the context of an outbreak. Restrictions to their use in non-severe Ebola cases or for longitudinal monitoring, when viral loads are lower, may be appropriate. Highlighting the challenge in developing and evaluating Ebola RDTs, there were concerns regarding sample integrity and reference testing, and there is a need for additional research to validate these assays.

Tropical Laboratory Initiative: An innovative model for laboratory medicine in rural areas.

BACKGROUND: Communities in rural, low-resource settings often lack access to reliable diagnostics. This leads to missed and misdiagnosed cases of disease and contributes to morbidity and mortality. OBJECTIVE: This paper describes a model for providing local laboratory services to rural areas of Ghana, and provides suggestions on how it could be adapted and expanded to serve populations in a range of rural communities. METHODS: The Tropical Laboratory Initiative (TLI) system in Ghana comprises one central laboratory where samples delivered from clinics by motorbike riders are analysed. Test requests and results are communicated on a mHealth application, and the patient does not have to visit the laboratory or travel beyond the clinic to receive a test. The TLI also serves as a research base. The laboratory is accredited by the National Health Insurance Authority, and accepts the national health insurance. The TLI serves several communities in Amansie West, Ashanti region, and currently works with 10 clinics. The nearest hospital is a one-hour drive away and is the only other nearby facility for diagnostics beyond basic rapid tests. RESULTS: Demand for services has increased yearly since the launch in 2010, and the TLI currently provides over 1000 tests to approximately 350 patients monthly. The majority of patients are female, and the most common tests are for antenatal care. Our experience demonstrates that laboratory services can be affordable and most components already exist, even in rural areas. CONCLUSION: Ministries of health in low-resource settings should consider this model to complement the rapid tests available in clinics. Integrating with an insurance system promotes financial sustainability.

Performance of the BD-FACS Presto for CD4 count and hemoglobin measurement in a district hospital and rural laboratory in Ghana.

INTRODUCTION: In Ghana, initiation of Antiretroviral Therapy (ART) is recommended for all patients with an HIV diagnosis, regardless of CD4+ T-cell count. However, measurement of CD4 count remains an important metric for identifying patients with advanced HIV disease, and assessing a person's overall immune status, which informs the decision to offer opportunistic infection screening and prophylaxis. Access to CD4+ T cell count in rural health facilities remains a major challenge in Ghana and other resource-limited settings. This study aimed to validate the accuracy of the BD FACSPresto near-patient device for measurement of CD4 count and hemoglobin concentration against the FACSCount (CD4) and Sysmex (hemoglobin) diagnostic machines when operated in both a district hospital and rural laboratory, serving a network of health posts in Ashanti Region, Ghana. METHODOLOGY: In the first phase of the study, patients were recruited from a district hospital, and both venous and capillary blood samples were tested using the FACSCount and Sysmex as reference tests and compared to results of the FACSPresto performed in the clinic laboratory at the district hospital. In the second phase, patients were recruited from both the hospital and from rural health clinics, and samples were tested using the FACSPresto at a rural laboratory. Sensitivity and specificity among samples categorized into different clinically relevant CD4 count ranges were calculated, along with correlation between the Presto and the reference measurements, and mean and relative bias with limits of agreement. RESULTS: The FACSPresto was successfully operated in both clinical settings. A total of 59 samples in the first phase and 48 samples in the second phase were included. Positive bias was observed when comparing CD4 count measured by BD FACSPresto to FACSCount in the district hospital (bias = 44, LOA -72,160) and in the rural laboratory setting (bias = 74, LOA -96, 244). In addition, capillary blood samples were shown to give higher measures when compared to venous blood samples from the same participant. All results were statistically significant (p<0.05) apart from hemoglobin measurement in venous blood in the rural laboratory. Correlation coefficients were high for CD4 count measures and lower for hemoglobin measures. CONCLUSION: Overall, the Presto gave higher estimates of CD4 count compared to FACSCount, and hemoglobin measurements were higher than from Sysmex. Samples of capillary blood in turn gave higher results for both measurements compared to venous blood, consistent with previous analyses. These findings should be considered when selecting CD4 count machines for use at the point of care, especially in remote areas where capillary blood sampling may be preferable, but are likely balanced by device's ease of use, portability, and ability to expand access to services. These results are some of the first to demonstrate the accuracy of the FACSPresto in West Africa and show that this device can be successfully operated in a very rural lab setting and may therefore assist to provide CD4 count and hemoglobin concentration measurement to populations in need.

Could the Recent Zika Epidemic Have Been Predicted?

Given knowledge at the time, the recent 2015-2016 zika virus (ZIKV) epidemic probably could not have been predicted. Without the prior knowledge of ZIKV being already present in South America, and given the lack of understanding of key epidemiologic processes and long-term records of ZIKV cases in the continent, the best related prediction could be carried out for the potential risk of a generic Aedes-borne disease epidemic. Here we use a recently published two-vector basic reproduction number model to assess the predictability of the conditions conducive to epidemics of diseases like zika, chikungunya, or dengue, transmitted by the independent or concurrent presence of Aedes aegypti and Aedes albopictus. We compare the potential risk of transmission forcing the model with the observed climate and with state-of-the-art operational forecasts from the North American Multi Model Ensemble (NMME), finding that the predictive skill of this new seasonal forecast system is highest for multiple countries in Latin America and the Caribbean during the December-February and March-May seasons, and slightly lower-but still of potential use to decision-makers-for the rest of the year. In particular, we find that above-normal suitable conditions for the occurrence of the zika epidemic at the beginning of 2015 could have been successfully predicted at least 1 month in advance for several zika hotspots, and in particular for Northeast Brazil: the heart of the epidemic. Nonetheless, the initiation and spread of an epidemic depends on the effect of multiple factors beyond climate conditions, and thus this type of approach must be considered as a guide and not as a formal predictive tool of vector-borne epidemics.

Natural Products for Cancer Prevention: Clinical Update 2016.

OBJECTIVES: To present a clinical update of natural products for cancer prevention and provide oncology nurses with an evidence-based review of natural products for patient counseling and education. DATA SOURCES: Clinical trials published in PubMed. CONCLUSION: In the past 4 years since the publication of the original review there have been minimal changes in the conclusions of the published literature on the use of natural products for cancer prevention. To date, clinical trials have not demonstrated conclusive benefit of using natural products for cancer prevention, and current guidelines do not recommend their use. This review provides an update on published and ongoing trials and can serve as an updated resource for nurses. Evidence-based natural products databases can help nurses stay current with the scientific literature and be effective educators and health coaches for their patients, who can be influenced by marketing of unregulated products. IMPLICATIONS FOR NURSING PRACTICE: Patients often discuss the use of natural products with nurses. Nurses have an opportunity to educate and coach patients in effective preventive lifestyle practices.

Near Infrared Imaging As a Method of Studying Tsetse Fly (Diptera: Glossinidae) Pupal Development.

Near infrared (NIR) photography and video was investigated as a method for observing and recording intrapuparial development in the tsetse fly Glossina palpalis gambiensis and other Muscomorpha (Cyclorrhapha) Diptera. We showed that NIR light passes through the puparium, permitting images of the true pupae and pharate adult to be captured. Various wavelengths of NIR light from 880 to 1060 nm were compared to study the development of tsetse fly pupae from larviposition to emergence, using time-lapse videos and photographs. This study was carried out to advance our understanding of tsetse pupal development, specifically with the goal of improving a sorting technique which could separate male from female tsetse flies several days before emergence. Separation of the sexes at this stage is highly desirable for operational tsetse sterile insect technique control programmes, as it would permit the easy retention of females for the colony while allowing the males to be handled, irradiated and shipped in the pupal stage when they are less sensitive to vibration. In addition, it presents a new methodology for studying the pupal stage of many coarctate insects for many applications. NIR imaging permits observation of living pupae, allowing the entire development process to be observed without disruption.