A Beginner's Guide to Collecting Questing Hard Ticks (Acari: Ixodidae): A Standardized Tick Dragging Protocol

Tick-borne diseases are emerging globally, necessitating increased research and coordination of tick surveillance practices. The most widely used technique for active collection of host-seeking, human-biting tick vectors is 'tick dragging', by which a cloth is dragged across the top of the vegetation or forest floor and regularly checked for the presence of ticks. Use of variable dragging protocols limits the ability of researchers to combine data sets for comparative analyses or determine patterns and trends across different spatial and temporal scales. Standardization of tick drag collection and reporting methodology will greatly benefit the field of tick-pathogen studies. Based on the recommendations of the Center for Disease Control and Prevention and other ecological considerations, we propose that tick dragging should be conducted to sample at least 750 m2 along linear transects when habitat allows in a manner that reduces bias in the sampled area, and report density of each tick species and life stage separately. A protocol for constructing a standard drag cloth, establishing linear transects, and drag sampling is presented, along with a downloadable datasheet that can be modified to suit the needs of different projects. Efforts to align tick surveillance according to these standard best practices will help generate robust data on tick population biology.

[THE ITERATIVE APPROACH TO PRICING LABORATORY SERVICES FOR THE PROVISION OF MEDICAL AID (COPROPROCYCOSOPHICAL EXAMINATION ON LYAMBLIOSIS)]

The purpose of the study was to substantiate the theoretical and methodical principles of pricing for laboratory services in the diagnosis of giardiasis, taking into account their iterability and peculiarities of parasitic research methods. The methods of laboratory study of gum disease of native smear, treated with Lyulol solution, and ether-formalin enrichment on the criteria of their quality and effectiveness are analyzed. On the basis of the study of the effectiveness of the first and repeated analyzes, the conclusion on the iterative nature of laboratory studies of giardiasis and the effectiveness of the use of an iterative approach to the determination of prices for laboratory services is substantiated. The approaches to pricing laboratories providing diagnostic services for giardiasis in Ukraine are analyzed. The necessity of applying the price trajectory for laboratory diagnosis of giardiasis on the basis of multiplicity of researches (interactive approach) and the determination of the minimum and maximum price levels (the minimax approach) is proved. The main factors of pricing for laboratory diagnostics of giardiasis are identified and characterized: iterative research, economic efficiency, social value, value for the patient, competitiveness and reputation.

Reestablishing rigor in archaeological parasitology

Archaeological parasitology originated in the mid-twentieth century with interdisciplinary teams of specialists directed by archaeologists. The goals of such studies were detailed analyses of dietary, medicinal, and environmental factors that shaped the patterns of infection. By the 1970s, a cadre of unique coprolite analysts was trained to analyze macroscopic and microscopic remains for integrated reconstructions of the cultural determinants of parasitism. During these first phases of research, diagnostic rigor was maintained by direct training of specialists in parasitology and archaeology sub-disciplines including archaeobotany and archaeopalynology. Near the end of the twentieth century, however, "paleoparasitology" was defined as a separate field focusing on defining parasite distribution through time and space. Ironically, this focus resulted in an increase in misdiagnosis, especially prominent after 2000. Paleoparasitology does not explicitly include other specialized studies in it research design. Thus, dietary, environmental and medicinal inferences have been neglected or lost as samples were destroyed solely for the purpose of parasitological analysis. Without ancillary archaeological studies, paleoparasitology runs the risk of separation from archaeological context, thereby reducing its value to the archaeologists who recover samples for analysis.

Identification, Validation, and Application of Molecular Diagnostics for Insecticide Resistance in Malaria Vectors

Insecticide resistance is a major obstacle to control of Anopheles malaria mosquitoes in sub-Saharan Africa and requires an improved understanding of the underlying mechanisms. Efforts to discover resistance genes and DNA markers have been dominated by candidate gene and quantitative trait locus studies of laboratory strains, but with greater availability of genome sequences a shift toward field-based agnostic discovery is anticipated. Mechanisms evolve continually to produce elevated resistance yielding multiplicative diagnostic markers, co-screening of which can give high predictive value. With a shift toward prospective analyses, identification and screening of resistance marker panels will boost monitoring and programmatic decision making.

[THE FUNCTIONAL CONSTITUENT OF A BIOLOGICAL COMPONENT IN PROGRAMS FOR TRAINING SPECIALISTS IN THE AREA OF PARASITOLOGY FOR ACCREDITATION]

The paper considers the functional aspects of a biological component in programs for training specialists in the area of Parasitology for accreditation within the current enactments, including those on modernization of public health and additional professional education. The working program of the module "Fundamental Disciplines" has been used as an example to outline approaches to molding a medical parasitologist's capacity and readiness to solve professional tasks on the basis of knowledge of fundamental disciplines: biology, immunology, and medical geography. Education fundamentalization is shown to suggest more unsupervised work of a learner in the teaching process. The fundamental constituent of a biological component of the 'programs for training learners in the specialty of Parasitology for accreditation is shown in the interaction of all sections of this area with special and allied subjects.

An integrated parasitology: revealing the elephant through tradition and invention

The field of parasitology contributes to the elucidation of patterns and processes in evolution, ecology, and biogeography that are of fundamental importance across the biosphere, leading to a thorough understanding of biodiversity and varied responses to global change. Foundations from taxonomic and systematic information drive biodiversity discovery and foster considerable infrastructure and integration of research programs. Morphological, physiological, behavioral, life-history, and molecular data can be synthesized to discover and describe global parasite diversity, in a timely manner. In fully incorporating parasitology in policies for adaptation to global change, parasites and their hosts should be archived and studied within a newly emergent conceptual universe (the 'Stockholm Paradigm'), embracing the inherent complexity of host-parasite systems and improved explanatory power to understand biodiversity past, present, and future.

The quality of methods reporting in parasitology experiments

There is a growing concern both inside and outside the scientific community over the lack of reproducibility of experiments. The depth and detail of reported methods are critical to the reproducibility of findings, but also for making it possible to compare and integrate data from different studies. In this study, we evaluated in detail the methods reporting in a comprehensive set of trypanosomiasis experiments that should enable valid reproduction, integration and comparison of research findings. We evaluated a subset of other parasitic (Leishmania, Toxoplasma, Plasmodium, Trichuris and Schistosoma) and non-parasitic (Mycobacterium) experimental infections in order to compare the quality of method reporting more generally. A systematic review using PubMed (2000-2012) of all publications describing gene expression in cells and animals infected with Trypanosoma spp was undertaken based on PRISMA guidelines; 23 papers were identified and included. We defined a checklist of essential parameters that should be reported and have scored the number of those parameters that are reported for each publication. Bibliometric parameters (impact factor, citations and h-index) were used to look for association between Journal and Author status and the quality of method reporting. Trichuriasis experiments achieved the highest scores and included the only paper to score 100% in all criteria. The mean of scores achieved by Trypanosoma articles through the checklist was 65.5% (range 32-90%). Bibliometric parameters were not correlated with the quality of method reporting (Spearman's rank correlation coefficient <-0.5; p>0.05). Our results indicate that the quality of methods reporting in experimental parasitology is a cause for concern and it has not improved over time, despite there being evidence that most of the assessed parameters do influence the results. We propose that our set of parameters be used as guidelines to improve the quality of the reporting of experimental infection models as a pre-requisite for integrating and comparing sets of data.

Effects of modifying the World Health Organization standard operating procedures for malaria microscopy to improve surveillance in resource poor settings

BACKGROUND

Individuals with fever are screened for malaria in specially-established malaria diagnostic laboratories set up in rural hospitals in the Northern and Eastern Provinces of Sri Lanka. Large numbers of blood smears negative for malaria parasites are being screened daily. Good quality smears are essential to maintain a high diagnostic competency among the technical staff. The modifications made to the World Health Organization (WHO) standard operating procedures to improve the quality of smears have been studied.

METHODS

A blinded, controlled, interventional study was conducted in 22 intervention and 21 control malaria diagnostic laboratories. Changes were made to the WHO standard operating procedure protocols to prepare, stain and examine blood smears for malaria parasite detection which were implemented in intervention laboratories. These included wipe-cleaning slides, preparing both thick and thin smears on the same slide, reversing the order of collecting blood for thick and thin smears, dry fixing thick smear for 20-25 minutes under table lamp, polishing the edge of spreader slide with sand paper and fixing the thin smear with methanol if not stained within four hours. Parameters with respect to quality of the smear as per WHO criteria were studied using randomly selected slides, and time taken for the report to be issued was recorded in both groups before and after the intervention.

RESULTS

There were no significant differences observed in the parameters studied at baseline between the two groups or pre and post intervention in the control group. In the intervention group streak formation in thin smears was reduced from 29.4% to 5.0%. The average fixing time of thick smears was reduced from 2.4 hours to 20 minutes. Inappropriate thickness of thick smears reduced from 18.3% to 1.5%. Overall quality of thick smears and thin smears increased from 76.1% to 98.0% and 81.7% to 87.0%, respectively. The quality of slides bearing both thick and thin smears increased from 60.0% to 87.0%.

CONCLUSIONS

New protocols with amendments to the WHO standard technical procedures ensure that good quality blood smears are prepared rapidly to diagnose malaria and the time required to issue the reports was reduced.

Seroprevalence and risk factors for Toxocara infection in children from an urban large setting in Northeast Brazil

OBJECTIVES

This study aimed to standardize an "in house" immunoassay to detect anti-Toxocara IgG antibodies in human serum to estimate the seroprevalence of Toxocara infection, and to identify its potential risk factors in children living in poor areas of Salvador, a large northeastern Brazilian city.

METHODS

Parents of 1309 children answered a questionnaire containing possible risk factor for acquisition of this infection. Blood was collected and the presence of anti-Toxocara IgG antibodies was detected by indirect ELISA using T. canis larval excretory-secretory antigens in sera previously absorbed with Ascaris lumbricoides antigens.

RESULTS

Seroprevalence of Toxocara infection was 48.4%. Children's age, low maternal schooling, contact with dogs and cats, and household located in paved streets were shown to be risk factors for Toxocara infection.

CONCLUSIONS

The seroprevalence of Toxocara infection is high among children living in a poor urban setting of Brazil. The association of low maternal education with higher Toxocara infection supports studies showing that low socioeconomic status is a risk factor for the acquisition of this infection as a reflection of hygiene habits of the family. And both infected-dogs and cats may be involved in this parasite transmission in this children population.

First interlaboratory test for the detection of Alaria spp. mesocercariae in meat samples using the Alaria spp. mesocercariae migration technique (AMT)

Emerging and re-emerging zoonotic diseases affect both public and animal health and require the development and contemporary implementation of suitable detection methods. A growing number of findings of the mesocercarial stage of the digenean trematode Alaria alata in game inhabiting wetlands have necessitated the development of a specific detection method. With the Alaria spp. mesocercariae migration technique (AMT), a specific and sensitive detection method is now available. To make the method accessible to the official controls, method validation is necessary. In this context, interlaboratory tests (IT) are a key factor to demonstrate both (1) the suitability of the respective method and (2) the reference materials. In the first IT performed on this issue, 15 laboratories from nine German federal states took part. Every lab received two negative and four positive standard samples each as well as a standardized examination device for AMT, and a standard operating procedure. All participating laboratories showed very good results in terms of qualitative analysis: 96.7 % of the samples were assessed correctly positive or negative. An analysis of the qualitative performance shows that 263 (58.4 %) of 450 mesocercariae that were inserted in the meatballs were identified by the participants, and 5 (33.3 %) out of 15 labs were able to count at least 70 % of the Alaria spp. mesocercariae. A direct comparison with the results of the German Trichinella IT, which were conducted since 2004, shows that the overall sensitivity of the AMT is even higher than that registered for the reference method for Trichinella detection (e.g. 93 % in 2010). Also, in terms of quantitative analysis, AMT stands up to the comparison with the results from the German Trichinella IT. The refinement of the implementation protocol of this innovative, easy-to-use and cost-effective method harbours great potential for further optimization and successful implementation in the official controls.

[Assessment of effect and quality control for parasitological tests in national schistosomiasis surveillance sites]

OBJECTIVE

To understand the ability of pathogenic diagnosis for schistosomiasis japonica in the national surveillance sites and evaluate the effect of stool hatching method in the field, so as to provide the evidence for establishing a quality control system of pathogenic diagnosis of schistosomiasis in the surveillance sites.

METHODS

The data pertaining to the parasitological diagnosis of the residents with positive serological tests were collected in 81 national surveillance sites of 12 provinces in 2011, and the effects of the Kato-Katz technique and stool hatching method were evaluated and compared. The incubation quality control samples made by the national schistosomiasis diagnosis reference laboratory were detected by both Kato-Katz technique and stool hatching method using the single-blind method, and the results were analyzed and compared for the coincidence rate, misdiagnosis rate and missing diagnosis rate in all the county laboratories in 2012.

RESULTS

A total of 3 780 sero-positive residents were tested by using the Kato-Katz technique and stool hatching method in the 81 national surveillance sites in 2011, 127 persons were double egg-positive, 3 513 persons were double egg-negative, and the total coincidence rate was 96.30%. Totally 173 infected people were diagnosed by using the Kato-Katz technique and the positive detection rate was 4.58%; 221 infected people were diagnosed by using the stool hatching method and the positive detection rate was 5.85%. A total of 267 positive people were diagnosed by the Kato-Katz technique or the stool hatching method or both and the total positive detection rate was 7.06%, which was higher by 54.15% than that by using the single Kato-Katz technique (chi2 = 21.32, P < 0.01). In 2012, of 240 standard incubation quality control samples (160 positives, 80 negatives) detected by the technicians from the 80 surveillance sites, 105 samples were positive and 67 samples were negative, with a total coincidence rate of 71.67% (172/240) and a total missing diagnosis rate of 34.38% (55/160). Among them, the missing rate of the strong positive samples was 32.50% (26/80), the missing rate of the weakly positive samples was 36.25% (29/80), and the misdiagnosis rate of the negative samples was 16.25% (13/80). The detection rates of the incubation quality control samples were 61.11%, 80.00%, 77.08%, 90.48%, 58.33% and 59.26% in the surveillance sites of six provinces, including Anhui, Hubei, Hunan, Jiangsu, Jiangxi and Sichuan provinces, respectively, and a significant difference was found (chi2 = 14.27, P < 0.05).

CONCLUSIONS

The detection efficiency of the stool hatching method is superior to that of the Kato-Katz technique in the field. However, the levels of the technical personnel for the stool hatching method are relatively low in most of the surveillance sites. Therefore, the technical training should be strengthened.

[Problems of medical parasitology]

Situation on parasitic disease in Russia remains complex. Reduction of parasitology personnel had a negative impact on the quality of epidemiological control in the field of parasitic diseases and resulted in a decrease of awareness of physicians of therapeutic-prophylaxis institutions. The situation was aggravated by a lack of anti-malaria preparations and insufficient specter of anti-helminthic drugs. Uncontrolled increase of the number of domestic and stray dogs in cities was the reason for increase of morbidity by helminthoses and zoonoses--toxocarosis and dirofilariasis. Emergence in the south of Krasnodar Region of effective carriers Aedes aegypti, Aedes albopictus became a serious threat to biological safety of the country. These mosquitos are effective carriers of causative agents of mosquito viral fevers: yellow, Dengue, Chikungunya et al.

Towards the establishment of a consensus real-time qPCR to monitor Trypanosoma cruzi parasitemia in patients with chronic Chagas disease cardiomyopathy: a substudy from the BENEFIT trial

Quantitative real-time PCR (qPCR) is an accurate method to quantify Trypanosoma cruzi DNA and can be used to follow-up parasitemia in Chagas disease (CD) patients undergoing chemotherapy. The Benznidazole Evaluation for Interrupting Trypanosomiasis (BENEFIT) study is an international, multicenter, randomized, double-blinded and placebo-controlled clinical trial to evaluate the efficacy of benznidazole (BZ) treatment in patients with chronic Chagas cardiomyopathy (CCC). One important question to be addressed concerns the effectiveness of BZ in reducing overall parasite load in CCC patients, even in the absence of parasitological cure. This report describes the evaluation of multiple procedures for DNA extraction and qPCR-based protocols aiming to establish a standardized methodology for the absolute quantification of T. cruzi DNA in Guanidine-EDTA blood (GEB) samples. A panel of five primer sets directed to the T. cruzi nuclear satellite DNA repeats (Sat-DNA) and to the minicircle DNA conserved regions (kDNA) was compared in either SYBR Green or TaqMan systems. Standard curve parameters such as, amplification efficiency, coefficient of determination and intercept were evaluated, as well as different procedures to generate standard samples containing pre-established T. cruzi DNA concentration. Initially, each primer set was assayed in a SYBR Green qPCR to estimate parasite load in GEB samples from chronic Chagas disease patients. The results achieved from Bayesian transmutability analysis elected the primer sets Cruzi1/Cruzi2 (p=0.0031) and Diaz7/Diaz8 (p=0.0023) coupled to the QIAamp DNA Kit extraction protocol (silica gel column), as the most suitable for monitoring parasitemia in these patients. Comparison between the parasite burden of 150 GEB samples of BENEFIT patients from Argentina, Brazil and Colombia, prior to drug/placebo administration, was performed using Cruzi1/Cruzi2 primers in a SYBR Green approach. The median parasitemia found in patients from Argentina and Colombia (1.93 and 2.31 parasite equivalents/mL, respectively) was around 20 times higher than the one estimated for the Brazilian patients (0.1 parasite equivalents/mL). This difference could be in part due to the complexity of T. cruzi genetic diversity, which is a factor possibly implicated in different clinical presentations of the disease and/or influencing parasitemia levels in infected individuals from different regions of Latin America. The results of SYBR Green qPCR assays herein presented prove this methodology to be more cost efficient than the alternative use of internal fluorogenic probes. In addition, its sensitivity and reproducibility are shown to be adequate to detect low parasitemia burden in patients with chronic Chagas disease.

Can field-based mosquito feeding assays be used for evaluating transmission-blocking interventions?

A recent meta-analysis of mosquito feeding assays to determine the Plasmodium falciparum transmission potential of naturally infected gametocyte carriers highlighted considerable variation in transmission efficiency between assay methodologies and between laboratories. This begs the question as to whether mosquito feeding assays should be used for the evaluation of transmission-reducing interventions in the field and whether these field-based mosquito assays are currently standardized sufficiently to enable accurate evaluations. Here, we address biological and methodological reasons for the observed variations, discuss whether these preclude the use of field-based mosquito feeding assays in field evaluations of transmission-blocking interventions, and propose how we can maximize the precision of estimates. Altogether, we underscore the significant advantages of field-based mosquito feeding assays in basic malaria research and field trials.

Hexaplex PCR detection system for identification of five human Plasmodium species with an internal control

Malaria remains one of the major killers of humankind and persists to threaten the lives of more than one-third of the world's population. Given that human malaria can now be caused by five species of Plasmodium, i.e., Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, Plasmodium ovale, and the recently included Plasmodium knowlesi, there is a critical need not only to augment global health efforts in malaria control but also, more importantly, to develop a rapid, accurate, species-sensitive/species-specific, and economically effective diagnostic method for malaria caused by these five species. Therefore, in the present study, a straightforward single-step hexaplex PCR system targeting five human Plasmodium 18S small-subunit rRNAs (ssu rRNAs) was designed, and the system successfully detected all five human malaria parasites. In addition, this system enables the differentiation of single infection as well as mixed infections up to the two-species level. This assay was validated with 50 randomly blinded test and 184 clinical samples suspected to indicate malaria. This hexaplex PCR system is not only an ideal alternative for routine malaria diagnosis in laboratories with conventional PCR machines but also adds value to diagnoses when there is a lack of an experienced microscopist or/and when the parasite morphology is confusing. Indeed, this system will definitely enhance the accuracy and accelerate the speed in the diagnosis of malaria, as well as improve the efficacy of malaria treatment and control, in addition to providing reliable data from epidemiological surveillance studies.

[Procedure and indications of stool examination in parasitology]

Intestinal parasites are a public health problem in the world especially in tropical and subtropical countries. Despite the improvement in living standards and healthy conditions, these parasitoses remain relatively frequent in Tunisia. Stool specimen examination keeps the fundamental test for screening and diagnosis. It is to directly search the parasite. Respect for the right procedure of collection of stool is an essential step for the reliability and proper interpretation of results of this examination.

Comparison of the sensitivity of imprint and scraping techniques in the diagnosis of American tegumentary leishmaniasis in a referral centre in Rio de Janeiro, Brazil

American tegumentary leishmaniasis (ATL) is an infectious disease that presents a wide spectrum of clinical manifestations making parasitological tests important for its diagnosis. Direct examination, although considered of low sensitivity is still employed mainly in areas with poor laboratory infrastructure. The aim of this study was to standardize the method of collecting and reading the scraping procedure and to then compare sensitivity of this procedure on two sites of the lesion (outer edge-OE and inner edge-IE) and of the imprint against the reference method (isolation in culture) in a group of 110 patients treated at a Referral Center in Rio de Janeiro, Brazil. ATL diagnosis was confirmed in 40 patients (36.4%), 39 cases were caused by L. braziliensis and 1 by L. amazonensis. Imprint was positive in 28 patients and scraping in OE in 17 and in IE in 25 patients, resulting in sensitivity of 70%, 42.5%, and 62.5% respectively. When the three direct examinations were combined, sensitivity value attained 77.5%. Aspects related to ease and quality of the collected material, pain intensity and frequency of bleeding in the scraping procedure were also broached and discussed in this study. The parameters of accuracy presented indicate that the direct methods can be safely used in ATL diagnosis, principally in IE scraping, as it is easy to produce and the examination is not costly, which allows the procedure to be repeated at different moments which, in turn, increases the possibility of finding the parasite. Despite that the direct methods are technically widespread, they are not standardized and the parameters of accuracy are unknown. If we consider the high incidence of leishmaniasis in low-income areas, the implantation of standardized and selective methods would provide advances in the diagnosis of leishmaniasis.

[Analysis of the results of the SEIMC External Quality Control Program, 2007]

The External Quality Control Program of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) includes controls for bacteriology, serology, mycology, parasitology, mycobacteria, virology and molecular microbiology. This article presents the most important conclusions and lessons drawn from the 2007 controls. As a whole, the results obtained in 2007 confirm the excellent skill and good technical standards found in previous years. However, erroneous results can be obtained in any laboratory and in clinically relevant determinations. A few deviations were observed in some controls, calling for critical reflection. Once again, the results of this program highlighted the need to complement internal with external controls, such as those offered by the SEIMC program.

Web-based virtual microscopy for parasitology: a novel tool for education and quality assurance

Background

The basis for correctly assessing the burden of parasitic infections and the effects of interventions relies on a somewhat shaky foundation as long as we do not know how reliable the reported laboratory findings are. Thus virtual microscopy, successfully introduced as a histopathology tool, has been adapted for medical parasitology.

Methodology/Principal Findings

Specimens containing parasites in tissues, stools, and blood have been digitized and made accessible as a “webmicroscope for parasitology” (WMP) on the Internet (http://www.webmicroscope.net/parasitology).These digitized specimens can be viewed (“navigated” both in the x-axis and the y-axis) at the desired magnification by an unrestricted number of individuals simultaneously. For virtual microscopy of specimens containing stool parasites, it was necessary to develop the technique further in order to enable navigation in the z plane (i.e., “focusing”). Specimens were therefore scanned and photographed in two or more focal planes. The resulting digitized specimens consist of stacks of laterally “stiched” individual images covering the entire area of the sample photographed at high magnification. The digitized image information (∼10 GB uncompressed data per specimen) is accessible at data transfer speeds from 2 to 10 Mb/s via a network of five image servers located in different parts of Europe. Image streaming and rapid data transfer to an ordinary personal computer makes web-based virtual microscopy similar to conventional microscopy.

Conclusion/Significance

The potential of this novel technique in the field of medical parasitology to share identical parasitological specimens means that we can provide a “gold standard”, which can overcome several problems encountered in quality control of diagnostic parasitology. Thus, the WMP may have an impact on the reliability of data, which constitute the basis for our understanding of the vast problem of neglected tropical diseases. The WMP can be used also in the absence of a fast Internet communication. An ordinary PC, or even a laptop, may function as a local image server, e.g., in health centers in tropical endemic areas.

Here, we describe a novel tool to observe parasites by virtual microscopy on the Internet. Microscopy-based identification of parasites is the basis for both diagnostics and epidemiological assessment of parasite burden globally. Yet, quality assessment of diagnostic parasitology laboratories is difficult, as delivering identical educational specimens has been impossible. In this study, a series of parasite specimens on ordinary glass slides were digitized using a recently developed microscope scanner technique. Up to 50,000 images captured at high magnification are digitally stitched together to form a representation of the entire glass slide. These “virtual slides” digitized at a thousand-fold magnification can hold more than 60 gigabytes of data. Handling such large amounts of data was made possible because of efficient compression techniques and a viewing system adopted from the geospatial imaging industry. Viewing the samples on the Internet very much resembles, for example, the use of Google Maps, and puts only modest requirements on the viewer's computer. In addition, we captured image stacks at different focal planes, and developed a web-based viewing system for three-dimensional navigation in the specimens. This novel technique is especially valuable for detailed visualization of large objects such as helminth eggs in stool specimens.

Different methods, different results: temporal trends in the study of nested subset patterns in parasite communities

The search for nested subset patterns has become a powerful tool for understanding the processes shaping parasite communities. Here, we re-examine the results of past studies on nestedness in parasite communities, to assess how sensitive they are to the analytical method used. Using the metricNand the null model RANDOM1, the first method available to study nested patterns, early studies concluded that nestedness was infrequent in parasite communities. In contrast later studies, using instead the metricTand the nestedness temperature calculator (NTC), found that nested subset patterns were very common in parasite communities. Recently, a new algorithm, the binary matrix nestedness temperature calculator (BINMATNEST), has been proposed to quantify nestedness. Using data on 31 helminth communities of fish hosts, we show that applying the NTC yields consistently more significant nested patterns than whenNand RANDOM1 are used on the same data. The use of BINMATNEST produced results that depend on the choice of the null model. To provide a benchmark, a straightforward comparison between the observed frequencies of co-occurrences of species with those expected from their prevalence under random assembly was also made for each community. This test indicates that random structure occurs in practically all communities, even those where one of the nestedness analyses found a significant pattern. We demonstrate that the probability of finding a nested pattern in a parasite community depends entirely on the metric and null model chosen for analysis.

Rapid diagnostic tests compared with malaria microscopy for guiding outpatient treatment of febrile illness in Tanzania: randomised trial

OBJECTIVE

To compare rapid diagnostic tests (RDTs) for malaria with routine microscopy in guiding treatment decisions for febrile patients.

DESIGN

Randomised trial.

SETTING

Outpatient departments in northeast Tanzania at varying levels of malaria transmission.

PARTICIPANTS

2416 patients for whom a malaria test was requested.

INTERVENTION

Staff received training on rapid diagnostic tests; patients sent for malaria tests were randomised to rapid diagnostic test or routine microscopy

MAIN OUTCOME MEASURE

Proportion of patients with a negative test prescribed an antimalarial drug.

RESULTS

Of 7589 outpatient consultations, 2425 (32%) had a malaria test requested. Of 1204 patients randomised to microscopy, 1030 (86%) tested negative for malaria; 523 (51%) of these were treated with an antimalarial drug. Of 1193 patients randomised to rapid diagnostic test, 1005 (84%) tested negative; 540 (54%) of these were treated for malaria (odds ratio 1.13, 95% confidence interval 0.95 to 1.34; P=0.18). Children aged under 5 with negative rapid diagnostic tests were more likely to be prescribed an antimalarial drug than were those with negative slides (P=0.003). Patients with a negative test by any method were more likely to be prescribed an antibiotic (odds ratio 6.42, 4.72 to 8.75; P<0.001). More than 90% of prescriptions for antimalarial drugs in low-moderate transmission settings were for patients for whom a test requested by a clinician was negative for malaria.

CONCLUSIONS

Although many cases of malaria are missed outside the formal sector, within it malaria is massively over-diagnosed. This threatens the sustainability of deployment of artemisinin combination treatment, and treatable bacterial diseases are likely to be missed. Use of rapid diagnostic tests, with basic training for clinical staff, did not in itself lead to any reduction in over-treatment for malaria. Interventions to improve clinicians' management of febrile illness are essential but will not be easy.

TRIAL REGISTRATION

Clinical trials NCT00146796 [ClinicalTrials.gov].

Production and validation of durable, high quality standardized malaria microscopy slides for teaching, testing and quality assurance during an era of declining diagnostic proficiency

Background

Sets of Giemsa-stained, blood smear slides with systematically verified composite diagnoses would contribute substantially to development of externally validated quality assurance systems for the microscopic diagnosis of malaria.

Methods

whole blood from Plasmodium-positive donors in Cambodia and Indonesia and individuals with no history of risk for malaria was collected. Using standard operating procedures, technicians prepared Giemsa-stained thick and thin smears from each donor. One slide from each of the first 35 donations was distributed to each of 28 individuals acknowledged by reputation as having expertise in the microscopic diagnosis of malaria. These reference readers recorded presence or absence of Plasmodium species and parasite density. A composite diagnosis for each donation was determined based on microscopic findings and species-specific small subunit ribosomal RNA (ssrRNA) DNA polymerase chain reaction (PCR) amplification.

Results

More than 12, 000 slides were generated from 124 donations. Reference readers correctly identified presence of parasites on 85% of slides with densities <100 parasites/μl, which improved to 100% for densities >350 parasites/μl. Percentages of agreement with composite diagnoses were highest for Plasmodium falciparum (99%), followed by Plasmodium vivax (86%).

Conclusion

Herein, a standardized method for producing large numbers of consistently high quality, durable Giemsa-stained blood smears and validating composite diagnoses for the purpose of creating a malaria slide repository in support of initiatives to improve training and competency assessment amidst a background of variability in diagnosis is described.

Utility of the detection of Plasmodium parasites for the diagnosis of malaria in endemic areas

Background

In populations where the prevalence of infection with Plasmodium parasites is high, blood tests that identify Plasmodium parasites in patients with fever may lead to false positive diagnosis of malaria-disease. We characterised the diminishing value of the parasite detection test as a function of the prevalence of infection.

Methods

We computed the ability of the parasite detection test to identify malaria at various levels of prevalence (0% to 90%), assuming plausible estimates of sensitivity (95% and 85%) and specificity (99% and 95%) for the detection of parasites. In each situation, we computed likelihood ratios of malaria (or absence of malaria) for positive and negative parasite detection tests. Likelihood ratios were classified as clinically useful (≥ 10), intermediate (5–10), or unhelpful (<5).

Results

Likelihood ratios of positive tests were strongly related to the prevalence of infection in the general population: a positive test was unhelpful when the prevalence was 20% or more, and useful only when prevalence was 5% or less. The sensitivity and specificity of the test had little influence on these results. Likelihood ratios of negative tests were clinically useful when prevalence was 70% or less, but only for high levels of sensitivity (95%). If sensitivity was low (85%), the negative test was at best of intermediate utility, and was unhelpful if the prevalence of asymptomatic infection exceeded 30%.

Conclusion

Identification of Plasmodium parasites supports a diagnosis of malaria only in areas where the prevalence of Plasmodium infection is low. Wherever this prevalence exceeds about 20%, a positive test is clinically unhelpful.

[Discussion on the usage of terminology of some parasites and parasitic diseases]

According to the International Code of Zoological Nomenclature and the Standardized Nomenclature of Animal Parasitic Diseases (SNOAPAD), and considering the new advances in parasitology, the usage of the terminology of some parasites and parasitic diseases (such as Trichinella and trichinellosis, filariae and filariasis, Echinococcus and echinococcosis, etc.) was discussed.

Use of rapid diagnostic tests for diagnosis of malaria in the UK

BACKGROUND

Malaria is currently diagnosed almost exclusively by microscopy in clinical laboratories. The introduction of rapid diagnostic tests (RDTs) may be useful in achieving rapid detection of malaria parasites, especially in situations where malaria is not often seen or where staff are inexperienced.

AIM

To explore the use of RDT in UK laboratories.

METHODS

The current use of RDTs was surveyed in UK laboratories subscribing to the United Kingdom National External Quality Assessment Scheme blood parasitology and haematology schemes.

RESULTS

An overall survey response rate of 60.3% was seen. RDTs were found to be the preferred choice, either alone or in conjunction with microscopy in 31.2% of the samples examined during normal working hours and in 44.3% of the specimens examined on call.

CONCLUSIONS

During on-call hours, the use of RDTs was observed to increase and RDTs changed the diagnosis in 12% of laboratories. No established protocol for RDT use was, however, observed in the UK. A protocol that needs to be validated in the laboratory setting is suggested.

[Role of parasitological laboratories in sociohygienic monitoring]

The data available in the 2003-2004 statutory forms of the Russian Federation's subjects show that the parasitological laboratories of state sanitary surveillance centers in the Russian Federation make little use of sanitary-and-parasitological studies during sanitary monitoring. Studies of the parasitological indices of foodstuffs, drinking water, wastewater and their sediments are not under way in some regions. There is a poor material and technical basis in the parasitological laboratories; the work of parasitological laboratories does not meet the requirements stipulated in Sanitary Regulations 1.2.731-99 "Safety of work with microorganisms of pathogenicity groups 3-4 and with helmints". Intralaboratory monitoring is not always under way in the parasitological laboratories. Highly skilled staff is lacking. It is necessary to extend the list of sanitary-and-parasitological studies in accordance with MU 3.2.1756-03 "Epidemiological surveillance of parasitic diseases".

Nomenclature for parasitic diseases: cohabitation with inconsistency for how long and why?

The author surveys the early history of nomenclature for parasitic diseases or infections which led to the existing usage of synonymous names with diverse spellings for denominating the same disease entities. In order to diminish heterogeneity in nomenclatural usage, principles of the standardized nomenclature of parasitic diseases (SNOPAD) have been put forward by the World Association for the Advancement of Veterinary Parasitology. Pros and cons regarding the SNOPAD concept are discussed in seeking consensus terminology. The need for a standard nomenclature may be judged differently. SNOPAD is just a guideline based on carefully reasoned and clearly defined principles for those authors and editors dissatisfied with the existing heterogeneous and inconsistent nomenclatural usage and wish to rely on a uniform and standard disease nomenclature. The major suggestion of SNOPAD is the use solely of suffix -osis when disease name is coined from the name of a parasite taxon. Meanwhile, the proposed principles were found sensible and accepted more in the field of veterinary, less in medical parasitology. In a recent survey it has been revealed that the majority (73.8%) of 126 national language parasitological textbooks or compendia from 21 countries of Europe published since 1990 adopted consistent '-osis' disease terminology and the rest (26.2%) used a mixture of disease names ending in '-osis' and '-iasis' inconsistently. For achieving substantial shift towards the use of more consistent disease terminology, the interest and support of the parasitologists' community is required. Editorials and database producers hold the key to further progress provided they see the advantages of the use of a single name of worldwide currency for each disease entity.

Validation of molecular-diagnostic techniques in the parasitological laboratory

Diagnostic laboratories today often operate according to standard quality management procedures such as ISO/IEC 17025. This requires that only validated methods are used. Validation procedures help to document that a particular protocol used by the accredited laboratory has a guaranteed performance in that particular laboratory. Several study designs exist for validation procedures. Computer programmes are available to help with the statistical analysis of validation results. The agreement beyond chance of results obtained in the protocol that is to be validated can be compared to those achieved in an already established test (agreement). For a method that is used under routine conditions or for epidemiological studies, it is necessary to assess the diagnostic sensitivity and diagnostic specificity of the technique. These parameters can be estimated by comparing the method that needs to be validated with an existing reliable method ('gold standard'). This is done by testing a standard set of well-documented samples using both techniques in parallel. Approaches using Bayes' theorem are used to perform gold standard-free validations. Many PCR-based methods are characterised by an excellent analytical sensitivity and are thus good candidates for diagnostic tools of the required diagnostic sensitivity. However, the high level of analytical sensitivity can also make molecular techniques susceptible to cross-contamination and carry-over problems leading to false-positive results. Moreover, the presence of inhibitors can cause false-negative results. After an initial validation, test performance needs to be continuously monitored, e.g. by using combined Shewhart-CUSUM control routines, and test results compared to those obtained by other laboratories (proficiency testing).

Quality assessment of malaria laboratory diagnosis in South Africa

To assess the quality of malaria diagnosis in 115 South African laboratories participating in the National Health Laboratory Service Parasitology External Quality Assessment Programme we reviewed the results from 7 surveys from January 2000 to August 2002. The mean percentage incorrect result rate was 13.8% (95% CI 11.3-16.9%), which is alarmingly high, with about 1 in 7 blood films being incorrectly interpreted. Most participants with incorrect blood film interpretations had acceptable Giemsa staining quality, indicating that there is less of a problem with staining technique than with blood film interpretation. Laboratories in provinces in which malaria is endemic did not necessarily perform better than those in non-endemic areas. The results clearly suggest that malaria laboratory diagnosis throughout South Africa needs strengthening by improving laboratory standardization and auditing, training, quality assurance and referral resources.

[External quality control system in medical microbiology and parasitology in the Czech Republic]

The External Quality Control System (EQAS) of laboratory activities in medical microbiology and parasitology was implemented in the Czech Republic in 1993 with coded sera samples for diagnosis of viral hepatitis and bacterial strains for identification distributed to first participating laboratories. The number of sample types reached 31 in 2003 and the number of participating laboratories rised from 79 in 1993 to 421 in 2003. As many as 15.130 samples were distributed to the participating laboratories in 2003. Currently, almost all microbiology and parasitology laboratories in the Czech Republic involved in examination of clinical material participate in the EQAS. Based on the 11-year experience gained with the EQAS in the Czech Republic, the following benefits were observed: higher accuracy of results in different tests, standardisation of methods and the use of most suitable test kits.

Cryptosporidiosis in children in a north Jordanian paediatric hospital

We investigated the rate of infection by Cryptosporidium parvum among children from birth to 12 years attending Princess Rahma Teaching Hospital in Irbid, Jordan and evaluated various diagnostic methods. We collected single stool specimens from 300 children; 7 specimens were from children undergoing chemotherapy treatment for cancer. Diagnostic methods used for detection of infection were direct wet mount preparation, flotation concentration, cold Kinyoun Ziehl-Neelsen stain and direct immunofluorescence. We detected C. parvum oocysts in 112 samples (37.3%) using direct immunofluorescence, which showed the highest sensitivity. Source of drinking water appeared to be an important risk factor for transmission of infection. A higher incidence of infection was recorded during January-May, the rainy season.

External quality assessment schemes raise standards: evidence from the UKNEQAS parasitology subschemes

BACKGROUND

The burden of parasitic disease imported into the temperate zone is increasing, and in the tropics remains very high. Thus, high quality diagnostic parasitology services are needed, but to implement clinical governance a measure of quality of service is required.

AIM

To examine performance in the United Kingdom National External Quality Assessment Scheme for Parasitology for evidence of improved standards in parasite diagnosis in clinical specimens.

METHODS

Analysis of performance was made for the period 1986 to 2001, to look for trends in performance scores.

RESULTS

An overall rise in performance in faecal and blood parasitology schemes was found from 1986 to 2001. This was seen particularly in the identification of ova, cysts, and larvae in the faecal scheme, the detection of Plasmodium ovale and Plasmodium vivax in the blood scheme, and also in the correct identification of non-malarial blood parasites. Despite this improvement, there are still problems. In the faecal scheme, participants still experience difficulty in recognising small protozoan cysts, differentiating vegetable matter from cysts, and detecting ova and cysts when more than one species is present. In the blood scheme, participants have problems in identifying mixed malarial infections, distinguishing between P ovale and P vivax, and estimating the percentage parasitaemia. The reasons underlying these problems have been identified via the educational part of the scheme, and have been dealt with by distributing teaching sheets and undertaking practical sessions.

CONCLUSIONS

UK NEQAS for Parasitology has helped to raise the standard of diagnostic parasitology in the UK.

Detection of natural infections with Theileria annulata on calves at first theileriosis season: comparison of the Indirect Fluorescent Antibody Test (IFAT) and blood smears

The Indirect Fluorescent Antibody Test (IFAT) remains so far the most commonly used test for sero-epidemiological investigations on tropical theileriosis (infection of cattle with Theileria annulata). The present studies evaluated the ability of both IFAT with schizont antigen (schizont IFAT) and blood smears to detect infected animals just after the theileriosis season. This evaluation was performed on a group of 89 calves of known infection status for T. annulata at first disease season, from farms with endemic stability for tropical theileriosis. An additional retrospective group of 84 cattle free of infection was also used for the estimation of the specificity of the schizont IFAT. The sensitivity and the specificity of schizont IFAT were 88.9% (64/72) and 97% (98/101), respectively. Blood smears showed a lower sensitivity of 63.9% (46/72). The agreement between the two detection techniques and the infection status of the animals, evaluated by the Kappa coefficient, was 0.85 and 0.64 for IFAT and blood smears, respectively.

[Quality control of the diagnosis of malaria in the province of Cienfuegos, Cuba]

Data were collected by surveying all the technicians that worked at the different primary and secondary health care units. A quality control was carried out in the diagnosis of paludism in the 18 laboratories of the province of Cienfuegos. Various parameters were controlled. The method A considered 4 aspects to be evaluated: preparation of the material, sample taking, staining and microscopy. The method B consisted in an efficiency test by the observation of a set of laminae negative and positive to Plasmodium vivax and Plasmodium falciparum. In both cases, it was established a scoring scale. Besides, the physical conditions of the laboratory, the personnel permanence, as well as the time of experience in the diagnosis of paludism, were taken into account. The best results were obtained with the fixed personnel working in the paludism section. It was proved with a statistical significance level that the good category predominated for methods A and B after evaluating all the technicians. The study showed a better preparation of the personnel with less than 5 years of experience, which was related to the participation in the training course conducted at the provincial level by "Pedro Kouri" Tropical Medicine Institute 6 months before the investigation. Deficiencies were found in the conditions of the clinical and microbiology laboratories.

[Basics of PCR and related techniques applied in veterinary parasitology]

We attempte through the following overall review pertaining to the basics of PCR techniques (Polymerase Chain Reaction), to introduce the main applications used in veterinary parasitology. A major problem restricting the application possibilities of molecular biology techniques is of quantitative nature. Amplification techniques represent a real revolution, for it makes possible the production of tens, even hundreds of nanogrammes of sequences when starting from very small quantities. The PCR technique has dramatically transformed the strategies used so far in molecular biology and subsequently research and medical diagnosis.

Comparison of culture and different PCR assays for detection of Trichomonas vaginalis in self collected vaginal swab specimens

OBJECTIVES

DNA amplification techniques have become widely used for the diagnosis of sexually transmitted infections. For the detection of Trichomonas vaginalis, PCR techniques are not yet widely used despite the publication of several assays. The sensitivity and specificity of five independent primer sets were determined on self collected vaginal specimens obtained from female commercial sex workers.

METHODS

Self collected specimens were obtained from symptomatic and asymptomatic women attending a female sex workers clinic in Abidjan, Côte d'Ivoire. Two vaginal specimens were collected, the first one was processed for culture and the second was processed for PCR analysis. PCR techniques for trichomonads were performed, using the primers as reported by Riley (TVA5/TVA6), Kengne (TVK3/TVK7), Madico (BTUB 9/BTUB 2), Shiao (IP1/IP2), and Mayta (TV1/TV2). An EIA amplicon detection method was designed for each of the primer sets.

RESULTS

True positive specimens were defined as culture positive and/or two positive PCR results with EIA amplicon detection in any combination. According to this definition a prevalence of 20% was obtained compared to 7% obtained by culture. The PCR primer set TVK3/TVK7 gave the highest sensitivity (89.2%). Poor sensitivities were obtained with the primer sets TV1/TV2 (60.2%) and TVA5/TVA6 (63.9%). PCR showed a sensitivity improvement of 2.4% up to 12% when EIA was used for amplicon detection.

CONCLUSIONS

Overall, the sensitivities of the different PCR assays resulting from this study were lower than those previously described. These findings could be the result of the nature of the specimen population and suggests a strain variability.

Field evaluation of latex agglutination test for detecting urinary antigens in visceral leishmaniasis in Sudan

A latex agglutination test to detect urinary antigens for visceral leishmaniasis (VL) was studied. In 204 patients with suspected VL, KAtex had a sensitivity of 95.2% with good agreement with microscopy smears but poor agreement with 4 different serology tests. It was also positive in 2 confirmed VL cases co-infected with HIV. In all K4tex-positive confirmed cases actively followed up after treatment, the test became negative 1 month after completion of treatment. While IC4tex had a specificity of 100% in healthy endemic and non-endemic controls, the direct agglutination test (DAT) was positive in 14% of the KAtex-negative healthy endemic controls. KAtex is a simple addition to the diagnostics of VL particularly at field level and as a complementary test for the diagnosis of VL in smear-negative cases with positive DAT results.

[Quality control in parasitology]

Between 1990 and 1996 we coordinated a Quality Control (QC) Program in Parasitology directed to Public Health Institutions in Spain. Periodically, parasited specimens, mainly feces or blood, were sent to Microbiology Laboratories for identification. Each QC was accompanied by a short clinic and epidemiological information in order to help in the diagnostic approach. After the answers to the QC were received a bulletin that included the solution to the QC, comments on the several answers received and a chapter with parasitological themes related with the QC, was sent to each participating Laboratory. The bulletin was accompanied by a card that included a photograph and a short description of the organism object of the QC.

Direct identification of Leishmania species in biopsies from patients with American tegumentary leishmaniasis

Accurate identification of Leishmania species is important for monitoring clinical outcome, adequately targeting treatment, and evaluation of epidemiological risk in tegumentary leishmaniasis. This is especially the case in regions where several species coexist and for travel medicine where the geographical source of infection is not always obvious. Species identification presently depends on parasite isolation, which is not very sensitive and not necessarily representative of parasites actually present in human tissues. We evaluated a polymerase chain reaction (PCR) assay combining amplification of the gp63 genes and restriction fragment length polymorphism (RFLP) analysis (gp63 PCR-RFLP) for direct Leishmania species-identification in tissues collected from Peruvian patients in 1999. By comparison with a kinetoplast DNA-based PCR, our PCR assay showed a detection sensitivity of 85%. Three species were encountered among patient samples, Leishmania (Viannia) braziliensis, L. (V.) peruviana and L. (V.) guyanensis, and their frequency and geographical distribution corresponded to earlier epidemiological studies of leishmaniasis in Peru. However, unexpected results raised questions about (i) the contribution of human migration to the emergence of new foci of given species, (ii) the pathogenicity of some species, and (iii) the frequency of mixed or hybrid infections.

[Comparative study of four malaria diagnostic techniques used in Ivory Coast]

The biological diagnosis of malaria plays an important part in the patients' treatment for malaria. Thus, many techniques have been developed to reach this purpose. We have compared four of them concerning 196 patients from October, 1996 to January, 1997 in Abidjan. Thick blood film has been chosen as the technique for reference. It has come out that the plasmodic index was 18.3%. The Plasmodium falciparum has been the only encountered species. The different sensitivities of the QBC test and of the Parasight F test reached 100% against 83.3% in the case of the thin blood film. The QBC test and the thin blood film had each a specificity of 100% against 88.1% for the Parasight F test. Unlike the QBC test, the thick blood film and the thin blood film have remained the most difficult to be realised. Therefore, the analysis of parameters of credibility (sensitivity, specificity), predictable values and the time involved will allow in a given situation to use the appropriate biological diagnosis technique.

Resolution on teaching veterinary parasitology. World Association for the Advancement of Veterinary Parasitology (WAAVP)

The principles of this resolution were adopted by the General Assembly of the WAAVP on 30 August 2001 at the occasion of the 18th International WAAVP Congress in Stresa, Italy. The resolution has been published in [WAAVP Newslett. 5 (1) (2002) 3-4] and is added to the series of manuscripts on teaching of veterinary parasitology published in this issue, as it defines minimum requirements of contact hours in undergraduate teaching of veterinary parasitology.

[Evaluation of the Malaria Evaluation Program in the national laboratory network in Colombia]

In 1995, the Parasitology Group--National Reference Laboratory--at the Instituto Nacional de Salud (INS) started a national malaria diagnosis program with the Public Health Laboratory Network which included training, indirect quality control, external quality control, technical assistance, advisory, reference and counter-reference, together with an annual review of the program. The purpose of this study was to carry out a three year (1997-1999) analysis of the program. In the indirect quality control program, average positive and negative concordances of 98% and 97%, respectively, and a kappa index of 0.95 were obtained by the state public health laboratories. In the external quality control program, an average concordance of 74.2% was obtained with an 89.2% participation of the registered laboratories. At the municipal level, the indirect quality control had an average concordance of 91.4% in positivity, 92.5% concordance in negativity, and a kappa index of 0.84. On the other hand, indirect quality control has been scarcely implemented by the state public health laboratories in the municipalities under their jurisdiction. In general, the program shows a good performance, despite some economic and conflict-related difficulties in the country, because people responsible at all levels for the Malaria Program have permanently carried out all other activities of the network, either according to annual programming or upon request. However, it is important to improve its coverage and the participation in its activities.

Field and laboratory comparative evaluation of ten rapid malaria diagnostic tests

The paper reports on a comparative evaluation of 10 rapid malaria tests available in South Africa in 1998: AccuCheck (AC, developmental), Cape Biotech (CB), ICT Malaria Pf (ICT1) and Pf/Pv (ICT2), Kat Medical (KAT), MakroMal (MM), OptiMAL (OP), ParaSight-F (PS), Quorum (Q), Determine-Malaria (DM). In a laboratory study, designed to test absolute detection limits, Plasmodium falciparum-infected blood was diluted with uninfected blood to known parasite concentrations ranging from 500 to 0.1 parasites per microlitre (P/microL). The 50% detection limits were: ICT1, 3.28; ICT2, 4.86; KAT, 6.36; MM, 9.37; CB, 11.42; DM, 12.40; Q, 16.98; PS, 20; AC, 31.15 and OP, 91.16 P/microL. A field study was carried out to test post-treatment specificity. Blood samples from malaria patients were tested with all products (except AC and DM) on the day of treatment and 3 and 7 days thereafter, against a gold standard of microscopy and polymerase chain reaction (PCR). OP and PS produced fewer false-positive results on day 7 (18 and 19%, respectively) than the other rapid tests (38-56%). However, microscopy, PCR, OP and PS disagreed largely as to which individuals remained positive. The tests were further compared with regard to general specificity, particularly cross-reactivity with rheumatoid factor, speed, simplicity, their ability to detect other species, storage requirements and general presentation.