A Simple, Inexpensive Method for Mark-Recapture of Ixodid Ticks

Mark-recapture techniques have been widely used and specialized to study organisms throughout the field of biology. To mark-recapture ticks (Ixodida), we have created a simple method to mark ticks using nail polish applied with an insect pin secured in a pencil that allows for a variety of questions to be answered. For measuring tick control efficacy, estimating population estimates, or measuring movement of ticks, this inexpensive mark-recapture method has been easily applied in the field and in the lab to provide useful data to answer a variety of questions about ticks.

Low-cost internal controls for detection of Giardia cysts in water samples

Giardia cysts stained with hot carbolfuchsin were used as internal controls in a concentration method for surface water samples. The morphological integrity of stained cysts and the stain's stability and intensity were tested with each of the chemical reagents used in the aluminum sulfate flocculation method. No alterations in morphology or color were noted. The stained cyst preparation has a low cost, high stability, and suitability for both light and immunofluorescent microscopy, making it affordable to researchers in low- and middle-income countries.

[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.

Analysis of the sporozoite ELISA for estimating infection rates in Mozambican anophelines

Comparisons were undertaken to investigate cost-effective methods of implementing the enzyme-linked immunosorbent assay (ELISA) for sporozoite determination in anophelines when large numbers require processing. Comparisons between ELISA plate reader and visual assessments were performed with Anopheles funestus and Anopheles gambiae s.l. (Diptera: Culicidae), as were comparisons between whole-body mosquito samples, heads and thoraces, and abdomens alone. Rates obtained from pools of five or 10 mosquitoes were compared with those for individual mosquitoes, as were rates obtained using different sampling methods. A total of 41 792 An. funestus and 9431 An. gambiae s.l. collected in light traps, and 22 323 An. funestus and 6860 An. gambiae s.l. from exit collections were analysed. Visual assessments gave results similar to those of machine readings. Sporozoite rates were similar in both species, as were rates by collection method. The use of whole mosquitoes increased estimates of infection rate by 0.6%. Pool size did not affect infection rates of An. gambiae s.l., but rates were higher among individually tested An. funestus than among those tested in pools. For large-scale surveys, the use of whole mosquitoes in pools of 10 mosquitoes, with correction for overestimation, and the noting of results according to a simple three-stage visual assessment of positivity is the most cost-effective approach and is sufficient to obtain reliable data for comparative purposes.

Cost-effectiveness analysis of malaria rapid diagnostic test incentive schemes for informal private healthcare providers in Myanmar

BACKGROUND

The emergence of artemisinin-resistant Plasmodium falciparum parasites in Southeast Asia threatens global malaria control efforts. One strategy to counter this problem is a subsidy of malaria rapid diagnostic tests (RDTs) and artemisinin-based combination therapy (ACT) within the informal private sector, where the majority of malaria care in Myanmar is provided. A study in Myanmar evaluated the effectiveness of financial incentives vs information, education and counselling (IEC) in driving the proper use of subsidized malaria RDTs among informal private providers. This cost-effectiveness analysis compares intervention options.

METHODS

A decision tree was constructed in a spreadsheet to estimate the incremental cost-effectiveness ratios (ICERs) among four strategies: no intervention, simple subsidy, subsidy with financial incentives, and subsidy with IEC. Model inputs included programmatic costs (in dollars), malaria epidemiology and observed study outcomes. Data sources included expenditure records, study data and scientific literature. Model outcomes included the proportion of properly and improperly treated individuals with and without P. falciparum malaria, and associated disability-adjusted life years (DALYs). Results are reported as ICERs in US dollars per DALY averted. One-way sensitivity analysis assessed how outcomes depend on uncertainty in inputs.

RESULTS

ICERs from the least to most expensive intervention are: $1,169/DALY averted for simple subsidy vs no intervention, $185/DALY averted for subsidy with financial incentives vs simple subsidy, and $200/DALY averted for a subsidy with IEC vs subsidy with financial incentives. Due to decreasing ICERs, each strategy was also compared to no intervention. The subsidy with IEC was the most favourable, costing $639/DALY averted compared with no intervention. One-way sensitivity analysis shows that ICERs are most affected by programme costs, RDT uptake, treatment-seeking behaviour, and the prevalence and virulence of non-malarial fevers. In conclusion, private provider subsidies with IEC or a combination of IEC and financial incentives may be a good investment for malaria control.

Diagnostic accuracy and cost-effectiveness of alternative methods for detection of soil-transmitted helminths in a post-treatment setting in western Kenya

OBJECTIVES

This study evaluates the diagnostic accuracy and cost-effectiveness of the Kato-Katz and Mini-FLOTAC methods for detection of soil-transmitted helminths (STH) in a post-treatment setting in western Kenya. A cost analysis also explores the cost implications of collecting samples during school surveys when compared to household surveys.

METHODS

Stool samples were collected from children (n = 652) attending 18 schools in Bungoma County and diagnosed by the Kato-Katz and Mini-FLOTAC coprological methods. Sensitivity and additional diagnostic performance measures were analyzed using Bayesian latent class modeling. Financial and economic costs were calculated for all survey and diagnostic activities, and cost per child tested, cost per case detected and cost per STH infection correctly classified were estimated. A sensitivity analysis was conducted to assess the impact of various survey parameters on cost estimates.

RESULTS

Both diagnostic methods exhibited comparable sensitivity for detection of any STH species over single and consecutive day sampling: 52.0% for single day Kato-Katz; 49.1% for single-day Mini-FLOTAC; 76.9% for consecutive day Kato-Katz; and 74.1% for consecutive day Mini-FLOTAC. Diagnostic performance did not differ significantly between methods for the different STH species. Use of Kato-Katz with school-based sampling was the lowest cost scenario for cost per child tested ($10.14) and cost per case correctly classified ($12.84). Cost per case detected was lowest for Kato-Katz used in community-based sampling ($128.24). Sensitivity analysis revealed the cost of case detection for any STH decreased non-linearly as prevalence rates increased and was influenced by the number of samples collected.

CONCLUSIONS

The Kato-Katz method was comparable in diagnostic sensitivity to the Mini-FLOTAC method, but afforded greater cost-effectiveness. Future work is required to evaluate the cost-effectiveness of STH surveillance in different settings.

Mini-FLOTAC, an innovative direct diagnostic technique for intestinal parasitic infections: experience from the field

BACKGROUND

Soil-transmitted helminths and intestinal protozoa infection are widespread in developing countries, yet an accurate diagnosis is rarely performed. The aim of this study was to evaluate the recently developed mini-FLOTAC method and to compare with currently more widely used techniques for the diagnosis of intestinal parasitic infections in different settings.

METHODOLOGY/PRINCIPAL FINDINGS

The study was carried out in Dharamsala, Himachal Pradesh, India, and in Bukumbi, Tanzania. A total of 180 pupils from two primary schools had their stool analyzed (n = 80 in Dharamsala and n = 100 in Bukumbi) for intestinal parasitic infections with three diagnostic methods: direct fecal smear, formol-ether concentration method (FECM) and mini-FLOTAC. Overall, 72% of the pupils were positive for any intestinal parasitic infection, 24% carried dual infections and 11% three infections or more. The most frequently encountered intestinal parasites were Entamoeba coli, Entamoeba histolytica/dispar, Giardia intestinalis, hookworm, (and Schistosoma mansoni, in Tanzania). Statistically significant differences were found in the detection of parasitic infections among the three methods: mini-FLOTAC was the most sensitive method for helminth infections (90% mini-FLOTAC, 60% FECM, and 30% direct fecal smear), whereas FECM was most sensitive for intestinal protozoa infections (88% FECM, 70% direct fecal smear, and 68% mini-FLOTAC).

CONCLUSION/SIGNIFICANCE

We present the first experiences with the mini-FLOTAC for the diagnosis of intestinal helminths and protozoa. Our results suggest that it is a valid, sensitive and potentially low-cost alternative technique that could be used in resource-limited settings--particularly for helminth diagnosis.

A TaqMan-based multiplex real-time PCR assay for the simultaneous detection of Wuchereria bancrofti and Brugia malayi

With the Global Program for the Elimination of Lymphatic Filariasis continuing to make strides towards disease eradication, many locations endemic for the causative parasites of lymphatic filariasis are realizing a substantial decrease in levels of infection and rates of disease transmission. However, with measures of disease continuing to decline, the need for time-saving and economical molecular diagnostic assays capable of detecting low levels of parasite presence is increasing. This need is greatest in locations co-endemic for both Wuchereria bancrofti and Brugia parasites because testing for both causative agents individually results in significant increases in labor and reagent costs. Here we describe a multiplex, TaqMan-based, real-time PCR assay capable of simultaneously detecting W. bancrofti and Brugia malayi DNA extracted from human bloodspots or vector mosquito pools. With comparable sensitivity to established singleplex assays, this assay provides significant cost and labor savings for disease monitoring efforts in co-endemic locations.

Neurocysticercosis: HP10 antigen detection is useful for the follow-up of the severe patients

BACKGROUND

The most severe clinical form of neurocysticercosis (NC) occurs when cysticerci are located in the subarachnoid space at the base of the brain (SaB). The diagnosis, monitoring and treatment of NC-SaB, constitutes a severe clinical challenge. Herein we evaluate the potential of the HP10 antigen detection enzyme-linked immunosorbent assay (HP10 Ag-ELISA) in the long term follow-up of NC-SaB cases. Assay performance was compared with that of Magnetic Resonance Imaging (MRI). In addition, the robustness of the HP10 Ag-ELISA was evaluated independently at two different institutions.

METHODOLOGY/PRINCIPAL FINDINGS

A double-blind prospective cohort trial was conducted involving 38 NC-SaB cases and a total of 108 paired serum and cerebrospinal fluid (CSF) samples taken at intervals of 4 to 8 months for up to 43 months. At each medical visit, results of sera and CSF HP10 Ag-ELISA and MRI obtained at last visit were compared and their accuracy was evaluated retrospectively, considering radiological evolution between appointments. In the long-term follow-up study, HP10 Ag-ELISA had a better agreement than MRI with retrospective radiological evaluation. High reproducibility of HP10 Ag-ELISA between laboratories was also demonstrated.

CONCLUSIONS

Results reported in this study establish for the first time the usefulness of the comparatively low cost HP10 Ag-ELISA for long term follow-up of NC-SaB patients.

A research agenda for helminth diseases of humans: towards control and elimination

Human helminthiases are of considerable public health importance in sub-Saharan Africa, Asia, and Latin America. The acknowledgement of the disease burden due to helminth infections, the availability of donated or affordable drugs that are mostly safe and moderately efficacious, and the implementation of viable mass drug administration (MDA) interventions have prompted the establishment of various large-scale control and elimination programmes. These programmes have benefited from improved epidemiological mapping of the infections, better understanding of the scope and limitations of currently available diagnostics and of the relationship between infection and morbidity, feasibility of community-directed or school-based interventions, and advances in the design of monitoring and evaluation (M&E) protocols. Considerable success has been achieved in reducing morbidity or suppressing transmission in a number of settings, whilst challenges remain in many others. Some of the obstacles include the lack of diagnostic tools appropriate to the changing requirements of ongoing interventions and elimination settings; the reliance on a handful of drugs about which not enough is known regarding modes of action, modes of resistance, and optimal dosage singly or in combination; the difficulties in sustaining adequate coverage and compliance in prolonged and/or integrated programmes; an incomplete understanding of the social, behavioural, and environmental determinants of infection; and last, but not least, very little investment in research and development (R&D). The Disease Reference Group on Helminth Infections (DRG4), established in 2009 by the Special Programme for Research and Training in Tropical Diseases (TDR), was given the mandate to undertake a comprehensive review of recent advances in helminthiases research, identify research gaps, and rank priorities for an R&D agenda for the control and elimination of these infections. This review presents the processes undertaken to identify and rank ten top research priorities; discusses the implications of realising these priorities in terms of their potential for improving global health and achieving the Millennium Development Goals (MDGs); outlines salient research funding needs; and introduces the series of reviews that follow in this PLoS Neglected Tropical Diseases collection, "A Research Agenda for Helminth Diseases of Humans."

Maternal serologic screening to prevent congenital toxoplasmosis: a decision-analytic economic model

OBJECTIVE

To determine a cost-minimizing option for congenital toxoplasmosis in the United States.

METHODOLOGY/PRINCIPAL FINDINGS

A decision-analytic and cost-minimization model was constructed to compare monthly maternal serological screening, prenatal treatment, and post-natal follow-up and treatment according to the current French (Paris) protocol, versus no systematic screening or perinatal treatment. Costs are based on published estimates of lifetime societal costs of developmental disabilities and current diagnostic and treatment costs. Probabilities are based on published results and clinical practice in the United States and France. One- and two-way sensitivity analyses are used to evaluate robustness of results. Universal monthly maternal screening for congenital toxoplasmosis with follow-up and treatment, following the French protocol, is found to be cost-saving, with savings of $620 per child screened. Results are robust to changes in test costs, value of statistical life, seroprevalence in women of childbearing age, fetal loss due to amniocentesis, and to bivariate analysis of test costs and incidence of primary T. gondii infection in pregnancy. Given the parameters in this model and a maternal screening test cost of $12, screening is cost-saving for rates of congenital infection above 1 per 10,000 live births. If universal testing generates economies of scale in diagnostic tools-lowering test costs to about $2 per test-universal screening is cost-saving at rates of congenital infection well below the lowest reported rates in the United States of 1 per 10,000 live births.

CONCLUSION/SIGNIFICANCE

Universal screening according to the French protocol is cost saving for the US population within broad parameters for costs and probabilities.

Improved Cryptosporidium parvum oocyst propagation using dexamethasone suppressed CF-1 mice

This study evaluates Cryptosporidium parvum oocyst production in dexamethasone suppressed CF-1 and C57BL/6 mice. Both models can yield 1 x 10(9) total oocysts over a 20-day production period; however, only 20 CF-1 mice are required to reliably achieve this goal compared to 40 C57BL/6 mice. Although oocyst yields per mouse are similar for both mouse strains, the survival rate for CF-1 mice is higher, resulting in reduced lost production time per study when compared to the C57BL/6 mice. This study presents a more efficient and cost effective dexamethasone suppressed murine model of propagating high concentrations of C. parvum oocysts.

The impact of response to the results of diagnostic tests for malaria: cost-benefit analysis

OBJECTIVE

Rapid diagnostic tests for malaria seem cost effective in standard analyses, but these do not take account of clinicians' response to test results. This study tested the impact of clinicians' response to rapid diagnostic test or microscopy results on the costs and benefits of testing at different levels of malaria transmission and in different age groups.

DESIGN

Cost-benefit analysis using a decision tree model and clinical data on the effectiveness of diagnostic tests for malaria, their costs, and clinicians' response to test results.

SETTING

Tanzania.

METHODS

Data were obtained from a clinical trial of 2425 patients carried out in three settings of varying transmission.

RESULTS

At moderate and low levels of malaria transmission, rapid diagnostic tests were more cost beneficial than microscopy, and both more so than presumptive treatment, but only where response was consistent with test results. At the levels of prescription of antimalarial drugs to patients with negative tests that have been found in observational studies and trials, neither test methodis likely to be cost beneficial, incurring costs 10-250% higher, depending on transmission rate, than would have been the case with fully consistent responses to all test results. Microscopy becomes more cost beneficial than rapid diagnostic tests when its sensitivity under operational conditions approaches that of rapid diagnostic tests.

CONCLUSIONS

Improving diagnostic methods, including rapid diagnostic tests, can reduce costs and enhance the benefits of effective antimalarial drugs, but only if the consistency of response to test results is also improved. Investing in methods to improve rational response to tests is essential. Economic evaluations of diagnostic tests should take into account whether clinicians' response is consistent with test results.

Rapid microsphere assay for identification of cryptosporidium hominis and cryptosporidium parvum in stool and environmental samples

Cryptosporidium hominis and Cryptosporidium parvum are associated with massive disease outbreaks worldwide. Because these two species have different transmission cycles, identification of these parasites to the species level in clinical samples may provide laboratory data of crucial importance in epidemiologic investigations. To date, the most reliable way to differentiate C. hominis and C. parvum is based on DNA sequencing analysis of PCR amplicons. Although this approach is very effective for differentiation of Cryptosporidium species, it is labor-intensive and time-consuming compared with methods that do not require DNA sequencing analysis as an additional step and that have been successfully used for specific identification of a number of pathogens. In this study, we describe a novel Luminex-based assay that can differentiate C. hominis from C. parvum in a rapid and cost-effective manner. The assay was validated by testing a total of 143 DNA samples extracted from clinical specimens, environmental samples, or samples artificially spiked with Cryptosporidium oocysts. As few as 10 oocysts per 300 microl of stools could be detected with this assay. The assay format includes species-specific probes linked to carboxylated Luminex microspheres that hybridize to a Cryptosporidium microsatellite-2 region (ML-2) where C. hominis and C. parvum differ by one nucleotide substitution. The assay proved to be 100% specific when samples that had been characterized by direct fluorescent antibody test (DFA) and DNA sequencing analysis were tested. In addition, the assay was more sensitive than DFA and provided species identification, which is an advantage for epidemiologic studies.

[Diagnostic kits in parasitology: which controls?]

The development of new diagnostic tools particularly for some parasitic "neglected diseases", is slowed or even hindered by limited resources assigned for basic and applied research in public institution and private sector. Even if the time-line and costs needed for developing a new In Vitro Diagnostic (IVD) test are generally lower compared to vaccines or new drugs, industry is poorly engaged in investing resources due to the perception of limited markets. To accelerate the development of diagnostics for the world's most deadly diseases, the World Health Organization's (WHO) Special Programme for Research and Training in Tropical Diseases (TDR), the United Nations Development Programme, the World Bank and the Gates Foundation, last year launched a new initiative, FIND (Foundation for Innovative New Diagnostics, www.finddiagnostics.org). The aim is to "apply the latest biotechnology innovations to develop and validate affordable diagnostic tests for diseases of the developing world". Ideally, a new diagnostic test should be accurately evaluated prior to use in medical practice. The first step would be a pre-clinical evaluation, an analytic study to determine its laboratory performance. A crucial point in this phase is the calibration of reagents (antigens, antibodies, DNA probes, etc.) against a standard reference preparation. WHO, through the WHO International Laboratories for Biological Standards, "provides International Biological Reference Preparations which serve as reference sources of defined biological activity expressed in an internationally agreed unit" (www.who.int/biologicals/IBRP/index.htm). Standardization allows "comparison of biological measurements worldwide" and ensures the reliability of diagnostic procedures. These preparations are generally intended for use in the characterization of the activity of secondary reference preparations (regional, national or in-house working standards). Unfortunately, international reference standards for parasitic diseases are not available at present, except for Toxoplasma antibodies. The first international standard reagent for Anti-Toxoplasma Serum was established in 1968 and at present, an international standard reference serum, Anti-toxoplasma serum, human TOXM is available at the National Institute for Biological Standards and Control (NIBSC) in UK. Several collaborative, multicenter studies were carried out to assess the performance of different methods and commercial tests for the diagnosis of toxoplasmosis, by providing to participating laboratories a panel of well-defined sera to be tested. A four-phase process following well-accepted methodological standards for the development of diagnostics, analogous to those internationally accepted for drugs and vaccines was recently proposed. The pre-clinical evaluation, the analytic study to assess sensitivity, specificity, predictive values in laboratory (phase I), should be followed by a proof of principle study to distinguish diseased from healthy persons in easily accessible populations (phase II). The evaluation of test performance in populations of intended use (phase III), and finally the delineation of cost-effectiveness and societal impact of new tests in comparison with existing tools (phase IV) should complete the validation procedure. In this context, national regulatory agencies play a major role in pre-market approval and post-market surveillance of IVDs. The European Community in 1998 approved a directive (Directive 98/79/EC) which rules the marketing of IVD medical devices, in order to harmonise the performance levels and standards in European countries. But, among IVDs for parasitic diseases, only those to detect congenital toxoplasmosis are submitted to defined procedures to provide the verification of products before their placing on the market and the surveillance after their marketing by a notified body, which perform appropriate examinations, tests and inspections to production facilities to verify if the device meets the requirements of the directive. In U.S.A., the Food and Drug Administration (FDA), through the Office of In Vitro Diagnostic Device Evaluation and Safety (OIVD), provides a comprehensive and regulatory activity for IVDs through pre-market evaluation and post-market surveillance. In developing countries, the scarcity of resources limits the procedures through which the national control authority can assure safety, quality and efficacy of products marketed, both imported and locally manufactured.

Living on the edge: parasite taxonomy in Australia

The way in which the huge Australian parasite fauna is described (discovery and naming) is the subject of this address. The approach to the task has never been well-organised so that a few groups of parasites are now relatively well-known because of the efforts of small groups of workers who have made sustained efforts in these groups, but equally some host-parasite systems have been almost completely ignored in that no worker has ever given them sustained attention. A high proportion of Australian parasites have been described by international workers. The sustaining of interest in a group of parasites over a long period is the key to real progress being made. The nature of the organisation of Australian science presently means that few positions are available for parasite taxonomists and funding for taxonomic research is scarce. Thus, parasite taxonomy (like the taxonomy of many groups of Australian plants and animals) can only be considered to be in crisis.

[Cost and workload in the parasitology laboratory derived from attention to the immigrant]

INTRODUCTION

To determine the cost and volume of work implied in providing a parasitological diagnosis when attending immigrants in a referral Tropical Medicine Unit.

METHODS

The total number and type of samples, requests processed and parasitology laboratory costs were quantified after attending 1258 immigrants during the period January 1989 to December 2001. Estimation of laboratory workload for the total was made on the basis of results from 748 of these patients. A reference to relative value units (RVU) was established for each of the tests used in the parasitological diagnosis. The evaluation included costs related to disposable material and time spent by technicians and medical staff, but did not include costs related to sample extraction or processing of the test request. Modified indicators from the Catalogue of Microbiology studies of the Valencian Community for the year 2000 were used, establishing the equivalence of 1 RVU as the value of one urine culture 5 2.39 3 (398 pesetas).

RESULTS

The overall cost was 99,680.99 3 (16,585,522 pesetas) or 45,934.94 RVU, and the cost per patient was 79.24 3 (13.185 pesetas) or 36.51 URV. The volume of work dedicated to attending immigrants was 9.7% of the total of samples received in the laboratory.

CONCLUSIONS

The cost and volume of work involved in attending this group of patients in the parasitology laboratory was not high.

The future of veterinary parasitology

Current evidence suggests research in veterinary parasitology is in decline despite its importance. This is particularly true in the UK where research funds have been diverted into BSE. Decline in interest in veterinary parasitology is at least in part due to the success of major pharmaceutical companies in producing a range of effective and safe anti-parasitic drugs. Research is needed because of the effects of parasites on animal welfare and the economic costs of parasites. However, there is little information on the actual costs of animal parasites. Another major reason for research is the development of drug resistance in protozoa, helminths and arthropods of veterinary importance. This is a serious problem particularly for sheep and goats in the southern hemisphere. A prioritised list of research requirements is suggested: (i) new drugs; (ii) resistance management; (iii) vaccines; (iv) breeding for resistance; (v) improved diagnostics; (vi) zoonoses; (vii) global warming and parasites. There is a major political challenge to raise the profile of veterinary parasitology and thus the funding essential for its advancement and the continued welfare and productivity of animals.

The future of veterinary parasitology: a time for change?

The future of veterinary parasitology is discussed at a time when R&D funding from the pharmaceutical industry is declining, yet the opportunities for veterinary parasitologists to diversify their activities has never been greater. Emerging and re-emerging areas requiring input from veterinary parasitologists include: veterinary public health; conservation and wildlife diseases; emerging and exotic infectious diseases; surveillance strategies; economic effects of parasitic diseases; aquaculture; molecular epidemiology; dietary and biological control of parasitic diseases; animal welfare; organic agricultural systems; novel vaccination strategies; drug target characterisation and rational drug design. Without change, the survival of veterinary parasitology as a viable, distinct discipline is under threat. In this environment, veterinary parasitologists must be adaptable, imaginative and pro-active in terms of setting the agendas for establishing strategic alliances, promoting research needs and developing research programs.

Parasites, parasitology and parasitologists

The science of parasitology is one of the many new disciplines of the twentieth century, as such it is a dynamic and rapidly evolving science which encompasses an increasing number of sub-disciplines and technologies. However, will the fragmentation involved in current methods of scientific enquiry and the competition for funding mean the decline of certain areas of parasitology or perhaps the complete loss of the discipline. This paper attempts to address these questions by considering the development of the discipline of parasitology especially within Australia and by considering the mechanisms of attaining funding for science. Technological change and its impact on parasitology is also considered, and requirements for maintenance of the discipline and its practitioners are suggested.

[Santa Fe triatomine bug detector. A high sensitivity and low cost design]

In 1987, Wisnivesky et al. developed "Maria" sensor box (MSB) which was assayed by sanitary agents, during a surveillance phase. In 1987, this design, with the same strategy, was assayed in an area of Santa Fe Province where very good results were obtained. Due to the deterioration of the Primary Health Care system, Santa Fe's Control Programme has carried out a study with MSB used by the owners of the houses. Some difficulties related with the internal structure of MSB were detected. A new model named "Detector SANTA FE" (DSF) was designed in order to overcome these difficulties. The sensitivity and cost of both models were compared in this study. Evaluation of 63 households was carried out with 172 elements distributed in bedrooms, in Villa Minetti (9 de Julio Department). One MSB and one DSF were placed on the walls above the bed-heads, separated by 30 cm, 1.5 m from the floor. Results show that 22 houses were positive after the evaluations. Of those 22 positives, 7 were detected by both models simultaneously, 1 only by MSB and 14 by DSF alone. Sensitivity for MSB was 36% and for DSF was 95%. Regarding efficiency, MSB costs $3.00 per unit, while DSF costs $1.00 per unit. The conclusion of the study is that DSF is remarkably more sensitive and cheaper than MSB.

Biodiversity: the scene in Australia and the role of the Australian Biological Resources Study

It is estimated that Australia is home to more than 1 million species, less than 15% of which have been described. No estimate is given for parasites, but brief speculation on the potential is presented. The Commonwealth Government has a clear role in funding biosystematic research in Australia in support of its Natural Heritage Trust programmes, the National Biodiversity Strategy and its responsibilities under the Biodiversity Convention, and in order to maintain adequate taxonomic capacity. As a Government programme of Environment Australia, the Australian Biological Resources Study has disbursed around A$12 million towards taxonomic and biogeographic research on animals and Protozoa. Approximately 10% of this amount has gone towards parasitology. With funding for the Study being in a somewhat parlous state, it is argued that priorities for research funding need to focus clearly on issues of national significance as expressed in Government policies, strategies and environment programmes. In addition to scientific merit, research questions and projected outputs in project applications for funding should be justified in terms of meeting the needs of end users in conservation management, primary industry, and the wider biological research community.

Research collaboration in parasitology between Indonesia and Australia

Indonesia and Australia are close neighbours sharing agro-ecological zones and common parasitological interests. Australia is an industrialised country and Indonesia is both industrialising and a developing country. The types of collaboration, contractual, collegiate, research collaboration and partnerships are briefly described. All forms of collaboration have and continue to exist between Australia and Indonesia. A survey of mammalian parasitology publications over the last 23 years indicates that the bulk of papers have been by Indonesian and non-Australian authors. Australian and Indonesian authors provided 4% of the total number of publications. The rational for collaboration is suggested to be the high degree of common multiple interests and the synergy of effort that can be derived from research partnerships. The most difficult issues in research collaboration are establishing the research priorities and, to a lesser extent, funding. The globalisation of the international research centre, International Livestock Research Institute, to include Asia will expand the opportunities for research collaboration. Details of the Australian Centre for International Agricultural Research mandate in supporting parasitology research collaboration is briefly described. The past and current research collaborative activities are reviewed and opportunities for future collaboration are listed.

Comparison of two methods for detection of Giardia cysts and Cryptosporidium oocysts in water

The steps of two immunofluorescent-antibody-based detection methods were evaluated for their efficiencies in detecting Giardia cysts and Cryptosporidium oocysts. The two methods evaluated were the American Society for Testing and Materials proposed test method for Giardia cysts and Cryptosporidium oocysts in low-turbidity water and a procedure employing sampling by membrane filtration, Percoll-Percoll step gradient, and immunofluorescent staining. The membrane filter sampling method was characterized by higher recovery rates in all three types of waters tested: raw surface water, partially treated water from a flocculation basin, and filtered water. Cyst and oocyst recovery efficiencies decreased with increasing water turbidity regardless of the method used. Recoveries of seeded Giardia cysts exceeded those of Cryptosporidium oocysts in all types of water sampled. The sampling step in both methods resulted in the highest loss of seeded cysts and oocysts. Furthermore, much higher recovery efficiencies were obtained when the flotation step was avoided. The membrane filter method, using smaller tubes for flotation, was less time-consuming and cheaper. A serious disadvantage of this method was the lack of confirmation of presumptive cysts and oocysts, leaving the potential for false-positive Giardia and Cryptosporidium counts when cross-reacting algae are present in water samples.

Evaluation of a commercially available ELISA assay for detection of Giardia lamblia in fecal specimens

A total of 417 fecal samples preserved in 10% buffered formalin and PVA were submitted to a commercial microbiology laboratory only for the detection of Giardia lamblia. Results from fecal specimens collected from 411 patients with gastrointestinal symptoms were compared using the following methods: (a) standard Ova & Parasite (O&P) concentration; (b) Alexon's ProspecT/Giardia enzyme-linked immunosorbent assay (ELISA) test, and (c) Meridian's Direct Fluorescent Antibody (DFA) Stain. In the 29 specimens in which G. lamblia was detected, 10 were O&P, DFA and ELISA positive, 17 were only ELISA positive and two were only Ova & Parasite and Direct Fluorescent Antibody positive. Of the 29 positive specimens, 22 were confirmed as true positives. The ELISA sensitivity was 91% and the specificity was 98%. The expense associated with these methods to detect the presence of Giardia is $11.00, $8.95, and $12.80, respectively. In symptomatic patients, the ProspecT/Giardia ELISA is a cost-effective, rapid, and sensitive method for detecting the presence of G. lamblia in fecal specimens.

[Congenital Chagas in Bolivia: comparative study of the effectiveness and cost of diagnostic methods]

Eight hundred and twenty newborn babies with a mean weight of < or = 2500g from the Maternity Hospital P Boland in Santa Cruz- Bolivia were examined in 1988-1989 by different methods to diagnose Chagas disease, (placental pathology, serology, parasitologically and clinically) to determine the efficiency and cost of these methods. The histopathological exam detected 87 cases of placenta infection. Out of this total 43 (49%) newborns were positive on the parasitological exam of the chord blood. This number increased by repeating the blood test during the first month of the baby's life, reaching the same level as the histopathology. With the serology, only 2 cases were detected as positive. The clinical sign with a high specificity in children infected with Chagas disease is the hepatosplenomegaly. The advantages and disadvantages regarding the cost and feasibilty of two strategies to detect congenital Chagas disease are being discussed. The first in based on the histopathology and the other over on parasitology. It is concluded that the control programs for this non vectorial form of Chagas' disease cannot be uniform since the aspects to consider are: prevalence of the disease, existence of the vector and availability to laboratory techniques.

New approaches to social and economic research on schistosomiasis in TDR (Special Programme for Research and Training in Tropical Diseases)

This paper describes new approaches to social and economic research being developed by the Social and Economic Research component of the Special Programme for Research and Training in Tropical Diseases of the World Health Organization. One of these is a study to assess the possibility of identifying high risk communities for urinary schistosomiasis through a "mailed" questionnaire approach distributed through an existing administrative system, thereby eliminating the need for face-to-face interviews by the research or disease control team. This approach, developed by the Swiss Tropical Institute in Ifakara, Tanzania, is currently being tested in seven other African countries. The paper also describes a change of emphasis of economic research on schistosomiasis, focusing on the intra-household effects of the disease on rural households, rather than, as previously done, studying the impact of the disease on the productivity of individual wage labourers. Other priorities involve the identification of epidemiological information needed for improved decision-making regarding acceptable treatment strategies in endemic areas with limited financial capacity, as well as research on how the adverse effects of economic development projects can be alleviated.

[Parasitic fecal analyses. Prescription, application and interpretation of results]

The increasing ease of intercontinental travel, immigration and the multiplication of cases of immune depression are such that European physicians are now frequently required to prescribe stool examinations for parasites. This article defines the laboratory approach to the diagnosis of intestinal parasites: indications for tests, based upon clinical and epidemiological data; methods of prescription and recommendations to patients; techniques used in the laboratory and their cost; minimum answer times; interpretation of results, in particular in the immune depressed.

Cryptosporidiosis: multiattribute evaluation of six diagnostic methods

Six diagnostic methods (Giemsa staining, Ziehl-Neelsen staining, auramine-rhodamine staining, Sheather's sugar flotation, an indirect immunofluorescence procedure, and a modified concentration-sugar flotation method) for the detection of Cryptosporidium spp. in stool specimens were compared on the following attributes: diagnostic yield, cost to perform each test, ease of handling, and ability to process large numbers of specimens for screening purposes by batching. A rank ordering from least desirable to most desirable was then established for each method by using the study attributes. The process of decision analysis with respect to the laboratory diagnosis of cryptosporidiosis is discussed through the application of multiattribute utility theory to the rank ordering of the study criteria. Within a specific health care setting, a diagnostic facility will be able to calculate its own utility scores for our study attributes. Multiattribute evaluation and analysis are potentially powerful tools in the allocation of resources in the laboratory.

Direct wet mounts versus concentration for routine parasitological examination: are both necessary?

The authors evaluated the usefulness of direct wet mount microscopic examination of stool samples for routine parasitologic diagnosis compared with formalin-ethyl acetate concentration detection. Over a three-year period, there were no instances in which an intestinal parasite was detected only by the direct wet mount examination. Elimination of routine direct wet mount examinations can reduce laboratory cost and save significant technologist time without decreasing the sensitivity of microscopic examinations for common parasitic agents.