Impact of aerial humidity on seasonal malaria: an ecological study in Zambia.

BACKGROUND: Seasonal patterns of malaria cases in many parts of Africa are generally associated with rainfall, yet in the dry seasons, malaria transmission declines but does not always cease. It is important to understand what conditions support these periodic cases. Aerial moisture is thought to be important for mosquito survival and ability to forage, but its role during the dry seasons has not been well studied. During the dry season aerial moisture is minimal, but intermittent periods may arise from the transpiration of peri-domestic trees or from some other sources in the environment. These periods may provide conditions to sustain pockets of mosquitoes that become active and forage, thereby transmitting malaria. In this work, humidity along with other ecological variables that may impact malaria transmission have been examined. METHODS: Negative binomial regression models were used to explore the association between peri-domestic tree humidity and local malaria incidence. This was done using sensitive temperature and humidity loggers in the rural Southern Province of Zambia over three consecutive years. Additional variables including rainfall, temperature and elevation were also explored. RESULTS: A negative binomial model with no lag was found to best fit the malaria cases for the full year in the evaluated sites of the Southern Province of Zambia. Local tree and granary night-time humidity and temperature were found to be associated with local health centre-reported incidence of malaria, while rainfall and elevation did not significantly contribute to this model. A no lag and one week lag model for the dry season alone also showed a significant effect of humidity, but not temperature, elevation, or rainfall. CONCLUSION: The study has shown that throughout the dry season, periodic conditions of sustained humidity occur that may permit foraging by resting mosquitoes, and these periods are associated with increased incidence of malaria cases. These results shed a light on conditions that impact the survival of the common malaria vector species, Anopheles arabiensis, in arid seasons and suggests how they emerge to forage when conditions permit.

Scientific Findings of the Southern and Central Africa International Center of Excellence for Malaria Research: Ten Years of Malaria Control Impact Assessments in Hypo-, Meso-, and Holoendemic Transmission Zones in Zambia and Zimbabwe.

For a decade, the Southern and Central Africa International Center of Excellence for Malaria Research has operated with local partners across study sites in Zambia and Zimbabwe that range from hypo- to holoendemic and vary ecologically and entomologically. The burden of malaria and the impact of control measures were assessed in longitudinal cohorts, cross-sectional surveys, passive and reactive case detection, and other observational designs that incorporated multidisciplinary scientific approaches: classical epidemiology, geospatial science, serosurveillance, parasite and mosquito genetics, and vector bionomics. Findings to date have helped elaborate the patterns and possible causes of sustained low-to-moderate transmission in southern Zambia and eastern Zimbabwe and recalcitrant high transmission and fatality in northern Zambia. Cryptic and novel mosquito vectors, asymptomatic parasite reservoirs in older children, residual parasitemia and gametocytemia after treatment, indoor residual spraying timed dyssynchronously to vector abundance, and stockouts of essential malaria commodities, all in the context of intractable rural poverty, appear to explain the persistent malaria burden despite current interventions. Ongoing studies of high-resolution transmission chains, parasite population structures, long-term malaria periodicity, and molecular entomology are further helping to lay new avenues for malaria control in southern and central Africa and similar settings.

Policy Implications of the Southern and Central Africa International Center of Excellence for Malaria Research: Ten Years of Malaria Control Impact Assessments in Hypo-, Meso-, and Holoendemic Transmission Zones in Zambia and Zimbabwe.

The International Centers of Excellence for Malaria Research (ICEMR) were established by the National Institute of Allergy and Infectious Diseases more than a decade ago to provide multidisciplinary research support to malaria control programs worldwide, operating in endemic areas and contributing technology, expertise, and ultimately policy guidance for malaria control and elimination. The Southern and Central Africa ICEMR has conducted research across three main sites in Zambia and Zimbabwe that differ in ecology, entomology, transmission intensity, and control strategies. Scientific findings led to new policies and action by the national malaria control programs and their partners in the selection of methods, materials, timing, and locations of case management and vector control. Malaria risk maps and predictive models of case detection furnished by the ICEMR informed malaria elimination programming in southern Zambia, and time series analyses of entomological and parasitological data motivated several major changes to indoor residual spray campaigns in northern Zambia. Along the Zimbabwe-Mozambique border, temporal and geospatial data are currently informing investigations into a recent resurgence of malaria. Other ICEMR findings pertaining to parasite and mosquito genetics, human behavior, and clinical epidemiology have similarly yielded immediate and long-term policy implications at each of the sites, often with generalizable conclusions. The ICEMR programs thereby provide rigorous scientific investigations and analyses to national control and elimination programs, without which the impediments to malaria control and their potential solutions would remain understudied.

Latent Class Analysis: Insights about design and analysis of schistosomiasis diagnostic studies.

Various global health initiatives are currently advocating the elimination of schistosomiasis within the next decade. Schistosomiasis is a highly debilitating tropical infectious disease with severe burden of morbidity and thus operational research accurately evaluating diagnostics that quantify the epidemic status for guiding effective strategies is essential. Latent class models (LCMs) have been generally considered in epidemiology and in particular in recent schistosomiasis diagnostic studies as a flexible tool for evaluating diagnostics because assessing the true infection status (via a gold standard) is not possible. However, within the biostatistics literature, classical LCM have already been criticised for real-life problems under violation of the conditional independence (CI) assumption and when applied to a small number of diagnostics (i.e. most often 3-5 diagnostic tests). Solutions of relaxing the CI assumption and accounting for zero-inflation, as well as collecting partial gold standard information, have been proposed, offering the potential for more robust model estimates. In the current article, we examined such approaches in the context of schistosomiasis via analysis of two real datasets and extensive simulation studies. Our main conclusions highlighted poor model fit in low prevalence settings and the necessity of collecting partial gold standard information in such settings in order to improve the accuracy and reduce bias of sensitivity and specificity estimates.

Diagnostic urinary cfDNA detected in human cystic echinococcosis.

Cystic echinococcosis (CE) is a major neglected tropical zoonotic disease caused by the tissue-dwelling larval stage of the cestode parasite Echinococcus granulosus. For individuals suspected of CE, the diagnostic standard is imaging using ultrasonography, X rays, or computed tomography. These resource-demanding and expensive procedures are rarely available in endemic rural areas where CE is most prevalent. There is a critical need for a new approach to identify CE patients so that they can be managed early in the course of their infection. This study reports on the results of a diagnostic approach that identifies E. granulosus-derived cell-free DNA (cfDNA) in the urine of CE patients. Utilizing PCR to amplify a fragment of a major tandem repeat element found in E. granulosus nuclear DNA, urine samples from all seven imaging-confirmed CE patients who harbored active liver cysts were positive. In addition, the urine samples from 2/4 patients who presented with non-viable/calcified liver cysts were also PCR positive for the repeat fragment. To our knowledge, this is the first report of using parasite cfDNA from urine to diagnose CE. This approach provides an easy to implement and cost-effective method to survey for the prevalence of E. granulosus in humans populations.

How far is the journey before malaria is knocked out of Zimbabwe? (or Africa): a commentary.

Recent publications and statements have drawn attention to a sustainable system of managing malaria control interventions globally but especially on the Continent of Africa. Arbitrary and unstable governments often interfere with health programmes, causing upsurges in malaria transmission as well as other health issues. A well-run health infrastructure will deal with public health as a whole. This commentary follows historical conditions in Zimbabwe where much original work on malaria control was initiated and implemented and where unstable conditions happened through local politics. These periodic conditions of instability on the ground challenge the current philosophical thrust to eradication and stress the need and role of an established and well-staffed health infrastructure in each country. Such facilities should be well staffed and supplied with drugs and point-of care diagnostic tests to manage malaria and should be sustained to serve the community even after tools that can eradicate malaria are developed.

Detection of Taenia solium DNA in the Urine of Neurocysticercosis Patients.

Neurocysticercosis (NCC), caused by Taenia solium larvae that reside in the central nervous system, results in serious public health and medical issues in many regions of the world. Current diagnosis of NCC is complex requiring both serology and costly neuroimaging of parasitic cysts in the brain. This diagnostic pipeline can be problematic in resource-constrained settings. There is an unmet need for a highly sensitive and clinically informative diagnostic test to complement the present diagnostic approaches. Here, we report that T. solium-derived cell-free DNA is readily detectable in the urine of patients with the subarachnoid and parenchymal forms of NCC, and discuss the potential utility of this approach in enhancing and refining T. solium diagnostics.

Transrenal DNA-based diagnosis of Strongyloides stercoralis (Grassi, 1879) infection: Bayesian latent class modeling of test accuracy.

For epidemiological work with soil transmitted helminths the recommended diagnostic approaches are to examine fecal samples for microscopic evidence of the parasite. In addition to several logistical and processing issues, traditional diagnostic approaches have been shown to lack the sensitivity required to reliably identify patients harboring low-level infections such as those associated with effective mass drug intervention programs. In this context, there is a need to rethink the approaches used for helminth diagnostics. Serological methods are now in use, however these tests are indirect and depend on individual immune responses, exposure patterns and the nature of the antigen. However, it has been demonstrated that cell-free DNA from pathogens and cancers can be readily detected in patient's urine which can be collected in the field, filtered in situ and processed later for analysis. In the work presented here, we employ three diagnostic procedures-stool examination, serology (NIE-ELISA) and PCR-based amplification of parasite transrenal DNA from urine-to determine their relative utility in the diagnosis of S. stercoralis infections from 359 field samples from an endemic area of Argentina. Bayesian Latent Class analysis was used to assess the relative performance of the three diagnostic procedures. The results underscore the low sensitivity of stool examination and support the idea that the use of serology combined with parasite transrenal DNA detection may be a useful strategy for sensitive and specific detection of low-level strongyloidiasis.

Why reinvent the wheel? Lessons in schistosomiasis control from the past.

Schistosomiasis has been of concern to local health authorities for most of the last century, and in spite of a lack of effective chemotherapy, the disease was dealt with quite effectively in many endemic countries by snail control and environmental management [1]. Much of this work was reported in journals prior to the electronic era but, sadly, seems to have been subsequently ignored. For many years, there followed a global hiatus on schistosomiasis control, and much of the local expertise was lost, but many things have changed more recently, mainly with the advent of generic and affordable praziquantel. With the increased availability of this drug, there has been an increasing interest in readdressing schistosomes as well as other neglected tropical diseases (NTDs). The strategic approach for this had been based almost exclusively on chemotherapy. Recently, however, questions arose about this strategy with evidence that chemotherapy alone was not succeeding [2]. Additional strategies were needed, and the "Towards Elimination of Schistosomiasis" (TES) 2017 Conference in Cameroon stressed an integrated PHASE strategy. This was in line with the WHO-NTD and WHO-AFRO 2014-2020 Regional Strategy on NTDs and directed emphasis on transmission control. Subsequently, this emphasis was discussed in a comprehensive review [3] that stressed the importance of such additions to any elimination programme. In reality, this means focusing on the aquatic snail hosts where and when transmission occurs, defining other risk factors such as water contact and latrine design and identifying improved sanitation and health education as essential components for elimination. For schistosomiasis reduction during the mid-20th century, transmission control was used extensively, but these facts are not well reported. Recent reviews have attempted to cover previous research [4,5], but sadly, they have left major knowledge gaps, particularly from Africa. These omissions also occurred in a recent WHO pamphlet on molluscicides [6]. Sadly, search engines used to retrieve information appear to miss much done by 5 African research institutes active from 1950 to 1990. It seems appropriate to take a look back to a time when fieldwork was a focus of research and transmission control was emphasised.

Point of care diagnosis of multiple schistosome parasites: Species-specific DNA detection in urine by loop-mediated isothermal amplification (LAMP).

Schistosomes are easily transmitted and high chance of repeat infection, so if control strategies based on targeted mass drug administration (MDA) are to succeed it is essential to have a test that is sensitive, accurate and simple to use. It is known and regularly demonstrated that praziquantel does not always eliminate an infection so in spite of the successes of control programs a residual of the reservoir survives to re-infect snails. The issue of diagnostic sensitivity becomes more critical in the assessment of program effectiveness. While serology, such as antigen capture tests might improve sensitivity, it has been shown that the presence of species-specific DNA fragments will indicate, most effectively, the presence of active parasites. Polymerase chain reaction (PCR) can amplify and detect DNA from urine residue captured on Whatman No. 3 filter paper that is dried after filtration. Previously we have detected S. mansoni and S. haematobium parasite-specific small repeat DNA fragment from filtered urine on filter paper by PCR. In the current study, we assessed the efficacy of detection of 86 urine samples for either or both schistosome parasites by PCR and loop-mediated isothermal amplification (LAMP) that were collected from a low to moderate transmission area in Ghana. Two different DNA extraction methods, standard extraction kit and field usable LAMP-PURE kit were also evaluated by PCR and LAMP amplification. With S. haematobium LAMP amplification for both extractions showed similar sensitivity and specificity when compared with PCR amplification (100%) verified by gel electrophoresis. For S. mansoni sensitivity was highest for LAMP amplification (100%) for standard extraction than PCR and LAMP with LAMP-PURE (99% and 94%). The LAMP-PURE extraction produced false negatives, which require further investigation for this field usable extraction kit. Overall high positive and negative predictive values (90% - 100%) for both species demonstrated a highly robust approach. The LAMP approach is close to point of care use and equally sensitive and specific to detection of species-specific DNA by PCR. LAMP can be an effective means to detect low intensity infection due to its simplicity and minimal DNA extraction requirement. This will enhance the effectiveness of surveillance and MDA control programs of schistosomiasis.

Diagnosis of Strongyloides stercoralis: Detection of parasite-derived DNA in urine.

Detecting infections of Strongyloides stercoralis is arduous and has low sensitivity. Clinically this is a major problem because chronic infections may disseminate in the host and lead to a life threatening condition. Epidemiologically, S. stercoralis is often missed in surveys as it is difficult to identify by standard stool examination procedures. We present, for the first time, evidence that the infection can be detected in filtered urine samples collected and processed in the field and subsequently assayed for the presence of parasite DNA. Urine specimens (∼40mL) were collected from 125 test and control individuals living in rural and peri-urban regions of Northern Argentina. From the same individuals, fresh stool specimens were processed using three different copropological methods. Urine specimens were filtered in the field through a 12.5cm Whatman No. 3 filter. The filters were dried and packed individually in sealable plastic bags with desiccant and shipped to a laboratory where DNA was recovered from the filter and PCR-amplified with primers specific to a dispersed repetitive sequence. Prevalence of S. stercoralis infection by stool culture and direct examination was 35/125 (28%), In contrast, PCR-based detection of parasite-specific trans-renal DNA in urine indicated that 56/125 (44.8%) carried the parasite. Of the patients that tested positive for urine-based parasite DNA, approximately half also tested positive in their stool specimens. There were 6.4% of cases where parasite larvae were seen in the stool but no DNA was amplified from the urine. As proof of principle, DNA amplification from urine residue reveals significantly more cases of S. stercoralis infection than the current standard stool examination techniques. Additional work is required to establish the relative utility, sensitivity and specificity of urine-based analysis compared to parasitological and nucleic acid detection from stool for clinical and epidemiological detection for S. stercoralis infection.

Comparison of a PfHRP2-based rapid diagnostic test and PCR for malaria in a low prevalence setting in rural southern Zambia: implications for elimination.

BACKGROUND: Rapid diagnostic tests (RDTs) detecting histidine-rich protein 2 (PfHRP2) antigen are used to identify individuals with Plasmodium falciparum infection even in low transmission settings seeking to achieve elimination. However, these RDTs lack sensitivity to detect low-density infections, produce false negatives for P. falciparum strains lacking pfhrp2 gene and do not detect species other than P. falciparum. METHODS: Results of a PfHRP2-based RDT and Plasmodium nested PCR were compared in a region of declining malaria transmission in southern Zambia using samples from community-based, cross-sectional surveys from 2008 to 2012. Participants were tested with a PfHRP2-based RDT and a finger prick blood sample was spotted onto filter paper for PCR analysis and used to prepare blood smears for microscopy. Species-specific, real-time, quantitative PCR (q-PCR) was performed on samples that tested positive either by microscopy, RDT or nested PCR. RESULTS: Of 3,292 total participants enrolled, 12 (0.4%) tested positive by microscopy and 42 (1.3%) by RDT. Of 3,213 (98%) samples tested by nested PCR, 57 (1.8%) were positive, resulting in 87 participants positive by at least one of the three tests. Of these, 61 tested positive for P. falciparum by q-PCR with copy numbers ≤ 2 x 10(3) copies/µL, 5 were positive for both P. falciparum and Plasmodium malariae and 2 were positive for P. malariae alone. RDT detected 32 (53%) of P. falciparum positives, failing to detect three of the dual infections with P. malariae. Among 2,975 participants enrolled during a low transmission period between 2009 and 2012, sensitivity of the PfHRP2-based RDT compared to nested PCR was only 17%, with specificity of >99%. The pfhrp gene was detected in 80% of P. falciparum positives; however, comparison of copy number between RDT negative and RDT positive samples suggested that RDT negatives resulted from low parasitaemia and not pfhrp2 gene deletion. CONCLUSIONS: Low-density P. falciparum infections not identified by currently used PfHRP2-based RDTs and the inability to detect non-falciparum malaria will hinder progress to further reduce malaria in low transmission settings of Zambia. More sensitive and specific diagnostic tests will likely be necessary to identify parasite reservoirs and achieve malaria elimination.

Malaria vector control at a crossroads: public health entomology and the drive to elimination.

Vector control has been at the core of successful malaria control. However, a dearth of field-oriented vector biologists threatens to undermine global reductions in malaria burden. Skilled cadres are needed to manage insecticide resistance, to maintain coverage with current interventions, to develop new paradigms for tackling 'residual' transmission and to target interventions as transmission becomes increasingly heterogeneous. Recognising this human resource crisis, in September 2013, WHO Global Malaria Programme issued guidance for capacity building in entomology and vector control, including recommendations for countries and implementing partners. Ministries were urged to develop long-range strategic plans for building human resources for public health entomology and vector control (including skills in epidemiology, geographic information systems, operational research and programme management) and to set in place the requisite professional posts and career opportunities. Capacity building and national ownership in all partner projects and a clear exit strategy to sustain human and technical resources after project completion were emphasised. Implementing partners were urged to support global and regional efforts to enhance public health entomology capacity. While the challenges inherent in such capacity building are great, so too are the opportunities to establish the next generation of public health entomologists that will enable programmes to continue on the path to malaria elimination.

Rapid diagnostic tests for malaria and health workers' adherence to test results at health facilities in Zambia.

BACKGROUND: In Zambia, there has been a large scaling up of interventions to control malaria in recent years including the deployment of rapid diagnostic tests (RDTs) to improve malaria surveillance data as well as guide malaria treatment in health facilities. The practical challenge is the impact of RDT results on subsequent management of patients. This study explored the role of RDTs in malaria diagnosis and the health workers' adherence to test results. METHODS: An observational prospective study was carried out at health centres in four districts, namely Chibombo, Chingola, Chipata, and Choma. Children under the age of five years with history of fever were recruited and the clinicians' use of RDT results was observed to establish whether prescriptions were issued prior to the availability of parasitological results or after, and whether RDT results influenced their prescriptions. RESULTS: Of the 2, 393 recruited children, 2, 264 had both RDT and microscopic results. Two in three (68.6%) children were treated with anti-malarials despite negative RDT results and almost half (46.2%) of these were prescribed Coartem®. Only 465 (19.4%) of the 2,393 children were prescribed drugs before receiving laboratory results. A total of 76.5% children were prescribed drugs after laboratory results. Children with RDT positive results were 2.66 (95% CI (2.00, 3.55)) times more likely to be prescribed anti-malarial drugs. Children who presented with fever at admission (although history of fever or presence of fever at admission was an entry criterion) were 42% less likely to be prescribed an anti-malarial drug compared to children who had no fever (AOR = 0.58; 95% CI (0.52, 0.65)). It was noted that proportions of children who were RDT- and microscopy-positive significantly declined over the years from 2005 to 2008. CONCLUSIONS: RDTs may contribute to treatment of febrile illness by confirming malaria cases from non-malaria cases in children under the age of five. However, the adherence of the health workers to prescribing anti-malarials to only RDT-positive cases at health facility level will still require to be explored further as their role is crucial in more precise reporting of malaria cases in this era towards malaria elimination as the target.

Remotely-sensed, nocturnal, dew point correlates with malaria transmission in Southern Province, Zambia: a time-series study.

BACKGROUND: Plasmodium falciparum transmission has decreased significantly in Zambia in the last decade. The malaria transmission is influenced by environmental variables. Incorporation of environmental variables in models of malaria transmission likely improves model fit and predicts probable trends in malaria disease. This work is based on the hypothesis that remotely-sensed environmental factors, including nocturnal dew point, are associated with malaria transmission and sustain foci of transmission during the low transmission season in the Southern Province of Zambia. METHODS: Thirty-eight rural health centres in Southern Province, Zambia were divided into three zones based on transmission patterns. Correlations between weekly malaria cases and remotely-sensed nocturnal dew point, nocturnal land surface temperature as well as vegetation indices and rainfall were evaluated in time-series analyses from 2012 week 19 to 2013 week 36. Zonal as well as clinic-based, multivariate, autoregressive, integrated, moving average (ARIMAX) models implementing environmental variables were developed to model transmission in 2011 week 19 to 2012 week 18 and forecast transmission in 2013 week 37 to week 41. RESULTS: During the dry, low transmission season significantly higher vegetation indices, nocturnal land surface temperature and nocturnal dew point were associated with the areas of higher transmission. Environmental variables improved ARIMAX models. Dew point and normalized differentiated vegetation index were significant predictors and improved all zonal transmission models. In the high-transmission zone, this was also seen for land surface temperature. Clinic models were improved by adding dew point and land surface temperature as well as normalized differentiated vegetation index. The mean average error of prediction for ARIMAX models ranged from 0.7 to 33.5%. Forecasts of malaria incidence were valid for three out of five rural health centres; however, with poor results at the zonal level. CONCLUSIONS: In this study, the fit of ARIMAX models improves when environmental variables are included. There is a significant association of remotely-sensed nocturnal dew point with malaria transmission. Interestingly, dew point might be one of the factors sustaining malaria transmission in areas of general aridity during the dry season.

Evaluating local vegetation cover as a risk factor for malaria transmission: a new analytical approach using ImageJ.

BACKGROUND: In places where malaria transmission is unstable or is transmitted under hypoendemic conditions, there are periods where limited foci of cases still occur and people become infected. These residual "hot spots" are likely reservoirs of the parasite population and so are fundamental to the seasonal spread and decline of malaria. It is, therefore, important to understand the ecological conditions that permit vector mosquitoes to survive and forage in these specific areas. Features such as local waterways and vegetation, as well as local ecology, particularly nocturnal temperature, humidity, and vegetative sustainability, are important for modeling local mosquito behavior. Vegetation around a homestead likely provides refuge for outdoor resting of these insects and may be a risk factor for malaria transmission. Analysis of this vegetation can be done using satellite information and mapping programs, such as Google Earth, but manual quantification is difficult and can be tedious and subjective. A more objective method is required. METHODS: Vegetation cover in the environment is reasonably static, particularly in and around homesteads. In order to evaluate and enumerate such information, ImageJ, an image processing software, was used to analyse Google Earth satellite imagery. The number of plants, total amount of vegetation around a homestead and its percentage of the total area were calculated and related to homesteads where cases of malaria were recorded. RESULTS: Preliminary results were obtained from a series of field trials carried out in South East Zambia in the Choma and Namwala districts from a base at the Macha District Hospital. CONCLUSIONS: This technique is objective, clear and simple to manipulate and has potential application to determine the role that vegetation proximal to houses may play in affecting mosquito behaviour, foraging and subsequent malaria incidence.

Detection of parasite-specific DNA in urine sediment obtained by filtration differentiates between single and mixed infections of Schistosoma mansoni and S. haematobium from endemic areas in Ghana.

Differential diagnosis of Schistosoma mansoni and S. haematobium, which often occur sympatrically in Africa, requires both urine and stool and the procedures are low in sensitivity. The standard diagnostic tests, such as Kato-Katz (KK) for S. mansoni eggs and presence of haematuria for S. haematobium both lack sensitivity, produce false-negative results and show reduced accuracy with decreasing intensity of infection. The need for a single diagnostic test with high sensitivity and specificity for both parasites is important as many African countries are implementing Mass Drug Administration (MDA) following recommendations of the World Health Organization (WHO). Eighty-six samples of urine sediment obtained by filtration were collected from a group of 5-23 years old people from an endemic area of southern Ghana. DNA was extracted from the urine sediment on filter paper from which a species-specific repeat fragment was amplified by polymerase chain reaction (PCR) with specific primers for S. mansoni and for S. haematobium. Additionally, all participants were tested by KK (stool) and dipstick for haematuria. Diagnostic parameters for all three tests were analyzed statistically. Amplification of species-specific DNA by PCR showed much higher sensitivity (99%-100%) and specificity (100%) compared to KK and haematuria (sensitivity: 76% and 30% respectively) for both schistosome species. The same pattern was observed when the data were stratified for age group and sex specific analysis. In addition PCR amplification detected DNA from 11 individuals infected with both parasites who were negative by KK and haematuria. This approach of detecting parasite specific DNA from either or both species in a single urine specimen is a practical advantage that avoids the need for two specimens and is more effective than standard tests including those based on serology. This promises to improve the effectiveness of surveillance of MDA control programs of schistosomiasis.

Diagnosis of Schistosoma mansoni without the stool: comparison of three diagnostic tests to detect Schistosoma [corrected] mansoni infection from filtered urine in Zambia.

Diagnosis for intestinal Schistosoma mansoni lacks sensitivity and is arduous to conduct. The standard diagnostic tests, Kato-Katz (KK) and circulating cathodic antigen (CCA) both lack sensitivity and with KK, require obtaining, transporting, and examining fresh stool. We compared diagnostic efficacy of KK, CCA, and polymerase chain reaction (PCR) to detect S. mansoni infection (species-specific DNA) from 89 filtered urine samples collected in Zambia. The PCR was the strongest indicator of positive cases with sensitivity and specificity of 100% in comparison to CCA (67% and 60%) and KK (50% and 100%). High positive and negative predictive values (100%) were also indicative of robustness of PCR. The same pattern was observed when stratified for sex and age group-specific analysis. Diagnosis of S. mansoni from filtered urine samples by PCR is an effective means to detect low intensity infection and would enhance the effectiveness of surveillance and control programs of schistosomiasis.