The economic value of identifying and treating Chagas disease patients earlier and the impact on Trypanosoma cruzi transmission

BACKGROUND

The World Health Organization's 2020 Goals for Chagas disease include access to antiparasitic treatment and care of all infected/ill patients. Policy makers need to know the economic value of identifying and treating patients earlier. However, the economic value of earlier treatment to cure and prevent the Chagas' spread remains unknown.

METHODS

We expanded our existing Chagas disease transmission model to include identification and treatment of Chagas disease patients. We linked this to a clinical and economic model that translated chronic Chagas disease cases into health and economic outcomes. We evaluated the impact and economic outcomes (costs, cost-effectiveness, cost-benefit) of identifying and treating different percentages of patients in the acute and indeterminate disease states in a 2,000-person village in Yucatan, Mexico.

RESULTS

In the absence of early treatment, 50 acute and 22 new chronic cases occurred over 50 years. Identifying and treating patients in the acute stage averted 0.5-5.4 acute cases, 0.6-5.5 chronic cases, and 0.6-10.8 disability-adjusted life years (DALYs), saving $694-$7,419 and $6,976-$79,950 from the third-party payer and societal perspectives, respectively. Treating in the indeterminate stage averted 2.2-4.9 acute cases, 6.1-12.8 chronic cases, and 11.7-31.1 DALYs, saving $7,666-$21,938 from the third-party payer perspective and $90,530-$243,068 from the societal perspective. Treating patients in both stages averted ≤9 acute cases and ≤15 chronic cases. Identifying and treating patients early was always economically dominant compared to no treatment. Identifying and treating patients earlier resulted in a cumulative cost-benefit of $7,273-$224,981 at the current cost of identification and treatment.

CONCLUSIONS

Even when identifying and treating as little as 5% of cases annually, treating Chagas cases in the acute and indeterminate stages reduces transmission and provides economic and health benefits. This supports the need for improved diagnostics and access to safe and effective treatment.

Cost-effectiveness analysis of thermotherapy versus pentavalent antimonials for the treatment of cutaneous leishmaniasis

OBJECTIVE

The treatment of cutaneous leishmaniasis is toxic, has contraindications, and a high cost. The objective of this study was to estimate the cost-effectiveness of thermotherapy versus pentavalent antimonials for the treatment of cutaneous leishmaniasis.

METHODS

Effectiveness was the proportion of healing and safety with the adverse effects; these parameters were estimated from a controlled clinical trial and a meta-analysis. A standard costing was conducted. Average and incremental cost-effectiveness ratios were estimated. The uncertainty regarding effectiveness, safety, and costs was determined through sensitivity analyses.

RESULTS

The total costs were $66,807 with Glucantime and $14,079 with thermotherapy. The therapeutic effectiveness rates were 64.2% for thermotherapy and 85.1% for Glucantime. The average cost-effectiveness ratios ranged between $721 and $1275 for Glucantime and between $187 and $390 for thermotherapy. Based on the meta-analysis, thermotherapy may be a dominant strategy.

CONCLUSION

The excellent cost-effectiveness ratio of thermotherapy shows the relevance of its inclusion in guidelines for the treatment.

Cost-effectiveness of meglumine antimoniate versus miltefosine caregiver DOT for the treatment of pediatric cutaneous leishmaniasis

BACKGROUND

Oral miltefosine has been shown to be non-inferior to first-line, injectable meglumine antimoniate (MA) for the treatment of cutaneous leishmaniasis (CL) in children. Miltefosine may be administered via in-home caregiver Directly Observed Therapy (cDOT), while patients must travel to clinics to receive MA. We performed a cost-effectiveness analysis comparing miltefosine by cDOT versus MA for pediatric CL in southwest Colombia.

METHODOLOGY/PRINCIPLE FINDINGS

We developed a Monte Carlo model comparing the cost-per-cure of miltefosine by cDOT compared to MA from patient, government payer, and societal perspectives (societal = sum of patient and government payer perspective costs). Drug effectiveness and adverse events were estimated from clinical trials. Healthcare utilization and costs of travel were obtained from surveys of providers and published sources. The primary outcome was cost-per-cure reported in 2015 USD. Treatment efficacy, costs, and adherence were varied in sensitivity analysis to assess robustness of results. Treatment with miltefosine resulted in substantially lower cost-per-cure from a societal and patient perspective, and slightly higher cost-per-cure from a government payer perspective compared to MA. Mean societal cost-per-cure were $531 (SD±$239) for MA and $188 (SD±$100) for miltefosine, a mean cost-per-cure difference of +$343. Mean cost-per-cure from a patient perspective were $442 (SD ±$233) for MA and $30 (SD±$16) for miltefosine, a mean difference of +$412. Mean cost-per-cure from a government perspective were $89 (SD±$55) for MA and $158 (SD±$98) for miltefosine, with a mean difference of -$69. Results were robust across a variety of assumptions in univariate and multi-way analysis.

CONCLUSIONS/SIGNIFICANCE

Treatment of pediatric cutaneous leishmaniasis with miltefosine via cDOT is cost saving from patient and societal perspectives, and moderately more costly from the government payer perspective compared to treatment with MA. Results were robust over a range of sensitivity analyses. Lower drug price for miltefosine could result in cost saving from a government perspective.

Cost-effectiveness of Chagas disease screening in Latin American migrants at primary health-care centres in Europe: a Markov model analysis

BACKGROUND

Chagas disease is currently prevalent in European countries hosting large communities from Latin America. Whether asymptomatic individuals at risk of Chagas disease living in Europe should be screened and treated accordingly is unclear. We performed an economic evaluation of systematic Chagas disease screening of the Latin American population attending primary care centres in Europe.

METHODS

We constructed a decision tree model that compared the test option (screening of asymptomatic individuals, treatment, and follow-up of positive cases) with the no-test option (screening, treating, and follow-up of symptomatic individuals). The decision tree included a Markov model with five states, related to the chronic stage of the disease: indeterminate, cardiomyopathy, gastrointestinal, response to treatment, and death. The model started with a target population of 100 000 individuals, of which 4·2% (95% CI 2·2-6·8) were estimated to be infected by Trypanosoma cruzi. The primary outcome was the incremental cost-effectiveness ratio (ICER) between test and no-test options. Deterministic and probabilistic analyses (Monte Carlo simulations) were performed.

FINDINGS

In the deterministic analysis, total costs referred to 100 000 individuals in the test and no-test option were €30 903 406 and €6 597 403 respectively, with a difference of €24 306 003. The respective number of quality-adjusted life-years (QALYs) gained in the test and no-test option were 61 820·82 and 57 354·42. The ICER was €5442. In the probabilistic analysis, total costs for the test and no-test option were €32 163 649 (95% CI 31 263 705-33 063 593) and €6 904 764 (6 703 258-7 106 270), respectively. The respective number of QALYs gained was 64 634·35 (95% CI 62 809·6-66 459·1) and 59 875·73 (58 191·18-61 560·28). The difference in QALYs gained between the test and no test options was 4758·62 (95% CI 4618·42-4898·82). The incremental cost-effectiveness ratio (ICER) was €6840·75 (95% CI 2545-2759) per QALY gained for a treatment efficacy of 20% and €4243 per QALY gained for treatment efficacy of 50%. Even with a reduction in Chagas disease prevalence to 0·05% and with large variations in all the parameters, the test option would still be more cost-effective than the no-test option (less than €30000 per QALY).

INTERPRETATION

Screening for Chagas disease in asymptomatic Latin American adults living in Europe is a cost-effective strategy. Findings of our model provide an important element to support the implementation of T cruzi screening programmes at primary health centres in European countries hosting Latin American migrants.

FUNDING

European Commission 7th Framework Program.

Optimal combinations of control strategies and cost-effective analysis for visceral leishmaniasis disease transmission

Visceral leishmaniasis (VL) is a deadly neglected tropical disease that poses a serious problem in various countries all over the world. Implementation of various intervention strategies fail in controlling the spread of this disease due to issues of parasite drug resistance and resistance of sandfly vectors to insecticide sprays. Due to this, policy makers need to develop novel strategies or resort to a combination of multiple intervention strategies to control the spread of the disease. To address this issue, we propose an extensive SIR-type model for anthroponotic visceral leishmaniasis transmission with seasonal fluctuations modeled in the form of periodic sandfly biting rate. Fitting the model for real data reported in South Sudan, we estimate the model parameters and compare the model predictions with known VL cases. Using optimal control theory, we study the effects of popular control strategies namely, drug-based treatment of symptomatic and PKDL-infected individuals, insecticide treated bednets and spray of insecticides on the dynamics of infected human and vector populations. We propose that the strategies remain ineffective in curbing the disease individually, as opposed to the use of optimal combinations of the mentioned strategies. Testing the model for different optimal combinations while considering periodic seasonal fluctuations, we find that the optimal combination of treatment of individuals and insecticide sprays perform well in controlling the disease for the time period of intervention introduced. Performing a cost-effective analysis we identify that the same strategy also proves to be efficacious and cost-effective. Finally, we suggest that our model would be helpful for policy makers to predict the best intervention strategies for specific time periods and their appropriate implementation for elimination of visceral leishmaniasis.

Cost of Pediatric Visceral Leishmaniasis Care in Morocco

Background

Visceral leishmaniasis (VL) is a neglected parasitic disease that is fatal if left untreated. VL is endemic in Morocco and other countries in North Africa were it mainly affects children from rural areas. In Morocco, the direct observation of Leishmania parasites in bone marrow aspirates and serological tests are used to diagnose VL. Glucantime is the first line of treatment. The objective of this study was to report the costs associated to standard clinical management of pediatric VL from the provider perspective in Morocco. As a secondary objective we described the current clinical practices and the epidemiological characteristics of pediatric VL patients.

Methods

From March to June 2014 we conducted a survey in eight hospitals treating pediatric VL patients in Morocco. A pro-forma was used to collect demographic, clinical and management data from medical records. We specifically collected data on VL diagnosis and treatment. We also estimated the days of hospitalization and the time to start VL treatment. Costs were estimated by multiplying the use of resources in terms of number of days in hospital, tests performed and drugs provided by the official prices. For patients receiving part of their treatment at Primary Health Centers (PHC) we estimated the cost of administering the Glucantime as outpatient. We calculated the median cost per VL patient. We also estimated the cost of managing a VL case when different treatment strategies were applied: inpatient and outpatient.

Results

We obtained data from 127 VL patients. The median total cost per pediatric VL case in Morocco is 520 US$. The cost in hospitals applying an outpatient strategy is significantly lower (307 US$) than hospitals keeping the patients for the whole treatment (636 US$). However the outpatient strategy is not yet recommended as VL treatment for children in the Moroccan guidelines. VL diagnosis and treatment regimens should be standardized following the current guidelines in Morocco.

The impact of human immunodeficiency virus (HIV) co-infection on the economic burden of cutaneous leishmaniasis (CL) in Brazil and potential value of new CL drug treatments

Convergence of geographic regions endemic for human immunodeficiency virus (HIV) and cutaneous leishmaniasis (CL) raise concerns that HIV co-infection may worsen CL burden, complicating already lengthy and costly CL treatments and highlighting a need for newer therapies. We constructed two Markov decision models to quantify impact of HIV on CL and help establish a target product profile for new CL treatments, accounting for co-infection. The HIV co-infection increased lifetime cost per CL case 11-371 times ($1,349-45,683) that of HIV-negative individuals ($123) and Brazil's CL burden from $1.6-16.0 million to $1.6-65.5 million. A new treatment could be a cost saving at ≤ $254 across several ranges (treatments seeking probabilities, side effect risks, cure rates) and continues to save costs up to $508 across treatment-seeking probabilities with a drug cure rate of ≥ 50%. The HIV co-infection can increase CL burden, suggesting more joint HIV and CL surveillance and control efforts are needed.

Opportunity cost for early treatment of Chagas disease in Mexico

Background

Given current neglect for Chagas disease in public health programs in Mexico, future healthcare and economic development policies will need a more robust model to analyze costs and impacts of timely clinical attention of infected populations.

Methodology/Principal Findings

A Markov decision model was constructed to simulate the natural history of a Chagas disease cohort in Mexico and to project the associated short and long-term clinical outcomes and corresponding costs. The lifetime cost for a timely diagnosed and treated Chagas disease patient is US$ 10,160, while the cost for an undiagnosed individual is US$ 11,877. The cost of a diagnosed and treated case increases 24-fold from early acute to indeterminate stage. The major cost component for lifetime cost was working days lost, between 44% and 75%, depending on the program scenario for timely diagnosis and treatment.

Conclusions/Significance

In the long term, it is cheaper to diagnose and treat chagasic patients early, instead of doing nothing. This finding by itself argues for the need to shift current policy, in order to prioritize and attend this neglected disease for the benefit of social and economic development, which implies including treatment drugs in the national formularies. Present results are even more relevant, if one considers that timely diagnosis and treatment can arrest clinical progression and enhance a chronic patient's quality of life.

Chagas disease is caused by the flagellated protozoan parasite Trypanosoma cruzi, vectored in Mexico in both rural and urban areas via one of 18 triatomine bug species. Despite ample morbidity and mortality evidence, however, health policy managers in Mexico have continued to neglect prevention, control and clinical attention for the disease. A computer simulation Markov model was programmed and fed with information from published evidence and an expert panel. The lifetime cost for a timely diagnosed and treated Chagas disease patient is US$ 10,160, while the cost for an undiagnosed individual is US$ 11,877. The cost of a diagnosed and treated case increases 24-fold from early acute to indeterminate stage. The major cost component for lifetime cost was working days lost, between 44% and 75%, depending on the program scenario for timely diagnosis and treatment. Timely medical attention for infected individuals is cheaper than doing nothing, especially if life and labor costs are included. The evidence provided, essential for decision-making, should be used to develop disease-specific prevention, control and patient clinical diagnosis and treatment policies for Chagas disease in Mexico.

Progress in the treatment of a neglected infectious disease: visceral leishmaniasis

Visceral leishmaniasis (kala-azar) is a disseminated intracellular protozoal infection. Most cases (90%) occur in the rural regions of five countries: India, Sudan, Nepal, Bangladesh and Brazil. As with other infectious diseases embedded in high-level poverty, developing and/or delivering new treatments for visceral leishmaniasis had been painfully slow or nonexistent. However, despite persistent unresolved obstacles (e.g., drug affordability), renewed interest in visceral leishmaniasis and numerous successful treatment trials have combined to turn a therapeutic corner in the past 5 years, yielding new alternatives to conventional pentavalent antimony. Advances include the use of low-cost generic pentavalent antimony, rediscovery of amphotericin B, short-course regimens via lipid formulations of amphotericin B, retesting injectible paromyomycin and, of clear-cut importance, identifying miltefosine (Impavido, Zentaris) as the first effective oral therapy for this neglected disease.

Effect of distillation waste water and plant hormones on spearmint growth and composition

BACKGROUND

Distillation waste water (DWW) is a by-product from steam distillation of essential-oil crops; and currently, it is discharged into streams and rivers. The effects of DWW from 13 essential-oil crops, extracts from two alkaloid-containing species, and three plant hormones (methyl jasmonate, MJ; gibberellic acid, GA3; and salicylic acid, SA) were evaluated on productivity, essential-oil content and composition of spearmint (Mentha spicata L.) cv. 'Native'.

RESULTS

Spearmint plant height was increased by the application of GA3 and Melissa officinalis DWW but suppressed by the application of Rosmarinus officinalis and Tagetes lucida DWW. Generally, MJ, GA3 and M. officinalis and Mentha arvensis DWW increased dry yields. The concentration of L-carvone in the oil ranged from 550 g kg(-1) (with Monarda citriodora DWW) to 670 g kg(-1) (with T. lucida DWW). M. citriodora DWW reduced the concentration of L-carvone in the oil by 23% relative to the control.

CONCLUSION

Results suggest that DWW from essential-oil crops may affect monoterpene synthesis in M. spicata and, hence, may have a direct effect on the essential oil composition. DWW from essential-oil crops may be used as a growth promoter and modifier of the essential oil composition of spearmint.

Cost-effectiveness analysis of combination therapies for visceral leishmaniasis in the Indian subcontinent

Background

Visceral leishmaniasis is a systemic parasitic disease that is fatal unless treated. We assessed the cost and cost-effectiveness of alternative strategies for the treatment of visceral leishmaniasis in the Indian subcontinent. In particular we examined whether combination therapies are a cost-effective alternative compared to monotherapies.

Methods and Findings

We assessed the cost-effectiveness of all possible mono- and combination therapies for the treatment of visceral leishmaniasis in the Indian subcontinent (India, Nepal and Bangladesh) from a societal perspective using a decision analytical model based on a decision tree. Primary data collected in each country was combined with data from the literature and an expert poll (Delphi method). The cost per patient treated and average and incremental cost-effectiveness ratios expressed as cost per death averted were calculated. Extensive sensitivity analysis was done to evaluate the robustness of our estimations and conclusions. With a cost of US$92 per death averted, the combination miltefosine-paromomycin was the most cost-effective treatment strategy. The next best alternative was a combination of liposomal amphotericin B with paromomycin with an incremental cost-effectiveness of $652 per death averted. All other strategies were dominated with the exception of a single dose of 10mg per kg of liposomal amphotericin B. While strategies based on liposomal amphotericin B (AmBisome) were found to be the most effective, its current drug cost of US$20 per vial resulted in a higher average cost-effectiveness. Sensitivity analysis showed the conclusion to be robust to variations in the input parameters over their plausible range.

Conclusions

Combination treatments are a cost-effective alternative to current monotherapy for VL. Given their expected impact on the emergence of drug resistance, a switch to combination therapy should be considered once final results from clinical trials are available.

Visceral leishmaniasis (VL) is a serious health problem in the Indian subcontinent affecting the rural poor. It has a significant economic impact on concerned households. The development of drug resistance is a major problem and threatens control efforts under the VL elimination initiative. With an unprecedented choice of antileishmanial drugs (but no newer compound in clinical development), policies that protect these drugs against the emergence of resistance are required. A possible strategy that has been successfully used for malaria and tuberculosis is the use of combination therapies. This study is the first comprehensive assessment of the cost-effectiveness of all possible mono- and combination therapies for the treatment of visceral leishmaniasis in the Indian subcontinent. The analysis was done from the societal perspective, including both health provider and household costs. The present work shows that combination treatments are a cost-effective alternative to current monotherapy for VL. Given their expected impact on emergence of drug resistance, the use of combination therapy should be considered in the context of the VL elimination programme in the Indian subcontinent.

A meta-analysis of the effectiveness of albendazole compared with metronidazole as treatments for infections with Giardia duodenalis

BACKGROUND

Metronidazole is the most commonly used drug for the treatment of giardiasis in humans. In spite of its therapeutic efficacy for giardiasis, low patient compliance, especially in children, side effects, and the emergence of metronidazole-resistant strains may restrict its use. Albendazole has been used to treat Giardia duodenalis infections in recent years. However, efficacy studies in vivo and in vitro have produced diverse results as to its effectiveness. A moderately benign side effect profile, combined with established efficacy against many helminths, renders it promising for treatment of giardiasis in humans.

METHODOLOGY AND PRINCIPAL FINDINGS

We performed a search in the PubMed, Scopus, EMBASE, the ISI Web of Science, LILIACS, and Cochrane Controlled Trials Register for trials published before February 2010 as well as in references of relevant research and review articles. Eight randomized clinical trials (including 900 patients) comparing the effectiveness of albendazole with that of metronidazole were included in meta-analysis. After extracting and validating the data, the pooled risk ratio (RR) was calculated using an inverse-variance random-effects model. Albendazole was found to be equally as effective as metronidazole in the treatment of giardiasis in humans (RR 0.97; 95% CI, 0.93, 1.01). In addition, safety analysis suggested that patients treated with albendazole had a lower risk of adverse effects compared with those who received metronidazole (RR 0.36; 95% CI, 0.10, 1.34), but limitations of the sample size precluded a definite conclusion.

CONCLUSIONS/SIGNIFICANCE

The effectiveness of albendazole, when given as a single dose of 400 mg/day for 5 days, was comparable to that of metronidazole. Patients treated with albendazole tended to have fewer side effects compared with those who took metronidazole. Given the safety, effectiveness, and low costs of albendazole, this drug could be potentially used as an alternative and/or a replacement for the existing metronidazole therapy protocols in the treatment of giardiasis in humans.

Single-dose liposomal amphotericin B for visceral leishmaniasis in India

BACKGROUND

Some 50% of patients with visceral leishmaniasis (kala-azar) worldwide live in the Indian state of Bihar. Liposomal amphotericin B is an effective treatment when administered in short courses. We wanted to determine whether the efficacy of a single infusion of liposomal amphotericin B was inferior to conventional parenteral therapy, consisting of 15 alternate-day infusions of amphotericin B deoxycholate.

METHODS

In this open-label study, we randomly assigned 412 patients in a 3:1 ratio to receive either liposomal amphotericin B (liposomal-therapy group) or amphotericin B deoxycholate (conventional-therapy group). Liposomal amphotericin B (at a dose of 10 mg per kilogram of body weight) was given once, and patients were discharged home 24 hours later. Amphotericin B deoxycholate, which was administered in 15 infusions of 1 mg per kilogram, was given every other day during a 29-day hospitalization. We determined the cure rate 6 months after treatment.

RESULTS

A total of 410 patients--304 of 304 patients (100%) in the liposomal-therapy group and 106 of 108 patients (98%) in the conventional-therapy group--had apparent cure responses at day 30. Cure rates at 6 months were similar in the two groups: 95.7% (95% confidence interval [CI], 93.4 to 97.9) in the liposomal-therapy group and 96.3% (95% CI, 92.6 to 99.9) in the conventional-therapy group. Adverse events in the liposomal-therapy group were infusion-related fever or rigors (in 40%) and increased anemia or thrombocytopenia (in 2%); such events in the conventional-therapy group were fever or rigors (in 64%), increased anemia (in 19%), and hypokalemia (in 2%). Nephrotoxicity or hepatotoxicity developed in no more than 1% of patients in each group.

CONCLUSIONS

A single infusion of liposomal amphotericin B was not inferior to and was less expensive than conventional therapy with amphotericin B deoxycholate. (ClinicalTrials.gov number, NCT00628719.)

Amphotericin B--fat emulsion in treatment of visceral leishmaniasis--a cost effective substitute for liposomal amphotericin B

In spite of high dosage and prolonged treatment schedule of sodium antimony gluconate, unresponsiveness and relapse ranging from 25 to 40% has been reported. The cure rate of 90 to 92.9% with amphotericin B-fat emulsion is comparable to that with liposomal amphotericin B (80 to 100%). Due to high cost liposomal amphotericin B is beyond the reach of most of the Indian patients, whereas the cost of treatment with amphotericin B-fat emulsion is quite affordable. Further large scale studies with amphotericin B-fat emulsion are required to evaluate its effectiveness in Indian kala-azar patients and to establish its optimal dose.

Prescription of fixed dose combination drugs for diarrhoea

Fixed-dose combinations (FDCs) of an antiprotozoal and an antibacterial, for treatment of diarrhoea, have been available in the Indian pharmaceutical market for about a decade. There is little evidence to substantiate this combination therapy. We evaluated 2,163 physician prescriptions for diarrhoea and found that 59 per cent of prescriptions were for FDCs. This is unethical because prescribing such combinations exposes a patient to higher risks of adverse drug reactions and also increases the chances of drug resistance. Physicians' prescribing practices in India are influenced by socioeconomic factors and the pharmaceutical industry's marketing techniques that include giving incentives to physicians to prescribe certain drugs.

Drug policy for visceral leishmaniasis: a cost-effectiveness analysis

OBJECTIVE

To facilitate the choice of the best visceral leishmaniasis (VL) treatment strategy for first-line health services in (VL)-endemic areas, we compared in a formal decision analysis the cost and the cost-effectiveness of the different available options.

METHODS

We selected four drug regimens for VL on the basis of frequency of use, feasibility and reported efficacy studies. The point estimates and the range of plausible values of effectiveness and cost were retrieved from a literature review. A decision tree was constructed and the strategy minimizing the cost per death averted was selected.

RESULTS

Treatment with amphotericin B deoxycholate was the most effective approach in the baseline analysis and averted 87.2% of all deaths attributable to VL. The least expensive and the most cost-effective treatment was the miltefosine regimen, and the most expensive and the least cost-effective was AmBisome treatment. The cost of drug and medical care are the main determinants of the cost-effectiveness ranking of the alternative schemes. Sensitivity analysis showed that antimonial was competitive with miltefosine in the low-resistance regions.

CONCLUSION

In areas with >94% response rates to antimonials, generic sodium stibogluconate remains the most cost-effective option for VL treatment, mainly due to low drug cost. In other regions, miltefosine is the most cost-effective option of treatment, but its use as a first-line drug is limited by its teratogenicity and rapid resistance development. AmBisome in mono- or combination therapy is too expensive to compete in cost-effectiveness with the other regimens.

Human African trypanosomiasis in a rural community, Democratic Republic of Congo

According to the World Health Organization, human African trypanosomiasis (HAT) (sleeping sickness) caused the loss of approximately 1.5 million disability-adjusted life years (DALYs) in 2002. We describe the effect of HAT during 2000-2002 in Buma, a rural community near Kinshasa in the Democratic Republic of Congo. We used retrospective questionnaire surveys to estimate HAT-related household costs and DALYs. The HAT outbreak in Buma involved 57 patients and affected 47 (21%) households. The cost to each household was equivalent to 5 months' income for that household. The total number of HAT-related DALYs was 2,145, and interventions to control HAT averted 1,408 DALYs. The cost per DALY averted was US $17. Because HAT has a serious economic effect on households and control interventions are cost-effective, considering only global burden of disease rankings for resource allocation could lead to misguided priority setting if applied without caution in HAT-affected countries.

Costs of patient management of visceral leishmaniasis in Muzaffarpur, Bihar, India

OBJECTIVES

To identify and quantify the direct and indirect economic cost of treatment for visceral leishmaniasis (VL) with conventional Amphotericin B deoxycholate, currently the first-line treatment in Muzaffarpur.

METHODS

Costs of patient management for VL were estimated from a societal and household perspective by means of a questionnaire designed for this study, interviews and financial reports.

RESULTS

The total cost of care per episode of VL from the societal perspective was estimated at US$355, equivalent to 58% of annual household income. The largest cost category was medical costs (55%), followed by indirect costs (36%) and non-medical costs (9%). The cost from the household perspective was equivalent to US$217. The largest cost category was indirect costs (59%), followed by medical costs (27%) and non-medical costs (15%). Loss of income because of illness and hospitalization and expenses for drugs were the largest cost components.

CONCLUSIONS

The economic costs related to VL are substantial, both to society and the patient. Public health authorities in Bihar should focus on policies that detect VL in the early stage and implement interventions that minimize the burden to households affected by VL.

Leishmaniasis and poverty

Leishmaniasis, a neglected tropical disease, has strong but complex links with poverty. The burden of leishmaniasis falls disproportionately on the poorest segments of the global population. Within endemic areas, increased infection risk is mediated through poor housing conditions and environmental sanitation, lack of personal protective measures and economically driven migration and employment that bring nonimmune hosts into contact with infected sand flies. Poverty is associated with poor nutrition and other infectious diseases, which increase the risk that a person (once infected) will progress to the clinically manifested disease. Lack of healthcare access causes delays in appropriate diagnosis and treatment and accentuates leishmaniasis morbidity and mortality, particularly in women. Leishmaniasis diagnosis and treatment are expensive and families must sell assets and take loans to pay for care, leading to further impoverishment and reinforcement of the vicious cycle of disease and poverty. Public investment in treatment and control would decrease the leishmaniasis disease burden and help to alleviate poverty.

Treatment options for visceral leishmaniasis

This review summarizes the current developments in therapy for visceral leishmaniasis. With the recent introduction of new drugs, the main limits in reducing deaths from visceral leishmaniasis are difficulty in diagnosis in the field and health inequality--patients lack of access to treatment. No new drugs are currently in the early stages of development. There are good reasons for the use of combination therapy; to prevent further development of resistance against the limited therapeutic options available.

Treatment of visceral leishmaniasis

The Leishmania donovani complex includes L. chagasi and L. infantum, and causes visceral leishmaniasis (VL), a disseminated and potentially fatal form of leishmaniasis. The treatment options for VL are limited. Pentavalent antimonials (Sbv) are the first-line treatment options worldwide except for in Europe and Sbv-unresponsive regions of India. Amphotericin B deoxycholate is the drug of choice in India, as are its lipid formulations in Europe. However, liposomal amphotericin B (AmBisome, Gilead Sciences, Inc.) is the best antileishmanial formulation, but its prohibitive cost limits its use in endemic countries. Preferential pricing of AmBisome for patients with VL may provide hope for these underprivileged patients. Oral miltefosine and paromomycin are the other drugs that have been recently developed. Limited therapeutic options, the potential for development of resistance and serious toxicity associated with antileishmanial drugs necessitates a change in the treatment policy. A shift from monotherapy to multi-drug combinations of short courses delivered at no or affordable cost, through directly observed therapy, seems to be the only way to develop the treatment of this disease.

Tinidazole: a nitroimidazole antiprotozoal agent

BACKGROUND

Tinidazole, a structural analogue of metrondazole, is an antiprotozoal agent that has been widely used in Europe and developing countries for >2 decades with established efficacy and acceptable tolerability. It was recently approved by the US Food and Drug Administration for the treatment of trichomoniasis, giardiasis, amebiasis, and amebic liver abscess.

OBJECTIVE

This article reviews the pharmacologic and pharmacokinetic properties and clinical usefulness of tinidazole.

METHODS

Relevant information was identified through a search of MEDLINE (1966-August 2005), Iowa Drug Information Service (1966-August 2005), and International Pharmaceutical Abstracts (1970-August 2005) using the terms tinidazole, Fasigyn, and nitroimidazole.

RESULTS

In vitro, tinidazole exhibits activity against pathogenic protozoa (eg, Tricbomonas vaginalis, Entamoeba bistolytica, Giardia duodenalis), a wide range of clinically significant anaerobic bacteria (eg, Bacteroides fragilis, Clostridium difficile), and the microaerophilic bacterium Helicobacter pylori. In susceptible protozoal and bacterial cells, tinidazole is reduced to cytotoxic intermediates that covalently bind to DNA, causing irreversible damage. In human adults, tinidazole had a bioavailability of 100% and a V(d) of 50.7 L, was minimally bound to plasma protein (12%), had a plasma elimination t((1/2)) of 12.3 hours, and was eliminated primarily by hepatic metabolism (approximately 63%). Dose adjustment does not appear to be necessary on the basis of race, sex, or renal function. No data were found on the disposition of tinidazole in patients with hepatic insufficiency; therefore, use of tinidazole in patients with severe hepatic impairment (Child-Pugh class C) is not recommended. Clinical cure rates in patients with trichomoniasis, giardiasis, amebiasis, and amebic liver abscess were generally >90%. In comparative trials, tinidazole was as effective as metronidazole in the treatment of trichomoniasis and was significantly more effective than metronidazole in the treatment of giardiasis (P < 0.05) and amebiasis (P < 0.05). The most commonly reported (>1%) adverse effects included bitter taste, nausea, abdominal discomfort, anorexia, vomiting, and fatigue. The recommended dosage of tinidazole is a single dose of 2 g for trichomoniasis and giardiasis, and 2 g/d for 3 to 5 days for amebiasis.

CONCLUSIONS

Tinidazole appears to be a promising agent for the treatment of trichomoniasis, giardiasis, amebiasis, and amebic liver abscess. Clinical studies are needed to evaluate the use of tinidazole against anaerobic bacteria and H pylori.

Infection of calves with Theileria annulata in Tunisia: Economic analysis and evaluation of the potential benefit of vaccination

A field study aiming to estimate the costs of tropical theileriosis was carried out in an endemic region of the North of Tunisia. Three farms were monitored for two successive summer seasons. A total number of 56 calves and 12 sentinel cows were monitored. Calves were ranked into four groups: non infected animals, diseased animals with clinical tropical theileriosis, sub-clinical Theileria annulata infected animals with anaemia and sub-clinical T. annulata infected animals without anaemia. The total costs due to disease and infection were estimated to be 15,115.058 TD (Euro 9388.20). A high proportion of these costs (50.81%) is accounted for by asymptomatic infection. Sub-clinical infections with anaemia showed the highest losses in live weight, while disease cases (prevalence 42.86%) are responsible for 23.64% of the losses with death as the most important element. A cost-benefit analysis of vaccination using a Tunisian attenuated cell line vaccine was also undertaken. Considering that the vaccine would cost 5 TD (Euro 3.10), the cost-benefit ratio of vaccination is 23.7. Sensitivity analysis of the vaccination costs shows that the indifference decision point is around 118 TD (Euro 73.29).

Cost-effectiveness of Chagas disease interventions in latin america and the Caribbean: Markov models

Chagas disease is a parasitic disease in Latin America. Despite vector control programs that have reduced incidence by 70%, there are at least 12-14 million prevalent cases. We used a Markov model to examine strategies for control and treatment of Chagas disease that compared annual costs, life expectancies, and cost-effectiveness of three vector control and drug treatment strategies. Vector control programs alone and vector control plus drug treatment are dominant over no vector control (i.e., less costly and save more lives), and vector control plus drug is highly cost-effective compared with vector control alone. We demonstrated expected changes in deaths over time resulting from various prevention approaches. Vector control affects primarily incidence, not decreasing deaths and prevalence for 30 years, while drug treatment affects prevalence and deaths immediately. The best strategy to combat Chagas disease is combinations of vector control and a potential new drug.

Treatment of visceral leishmaniasis in 2004

In 2004, visceral leishmaniasis (kala-azar) maintains its status as a neglected, if not "most neglected" disease. Lack of affordable new drugs, still a basic unsolved problem, has also been joined by additional therapeutic obstacles including large-scale resistance to pentavalent antimony (Sb) in India and coinfection with human immuno-deficiency virus in all endemic regions. Nevertheless, available treatment options have actually expanded because the energetic clinical trials effort of the past decade has yielded tangible advances. This progress includes successful application of less expensive generic Sb; rediscovery of the high-level efficacy of amphotericin B; implementation of short-course parenteral regimens (lipid formulations of amphotericin B); potential to replace Sb and amphotericin B with price-capped paromyomycin; and identification of the first effective oral agent (miltefosine). How to sustain and move this progress ahead, make new advances practical (e.g., affordable, and therefore, deployable), and how to translate promising experimental approaches into actual therapy remain difficult next steps in the treatment of kala-azar.

Leishmaniasis: current situation and new perspectives

Leishmaniasis represents a complex of diseases with an important clinical and epidemiological diversity. Visceral leishmaniasis (VL) is of higher priority than cutaneous leishmaniasis (CL) as it is a fatal disease in the absence of treatment. Anthroponotic VL foci are of special concern as they are at the origin of frequent and deathly epidemics (e.g. Sudan). Leishmaniasis burden remains important: 88 countries, 350 million people at risk, 500,000 new cases of VL per year, 1-1.5 million for CL and DALYs: 2.4 millions. Most of the burden is concentrated on few countries which allows clear geographic priorities. Leishmaniasis is still an important public health problem due to not only environmental risk factors such as massive migrations, urbanisation, deforestation, new irrigation schemes, but also to individual risk factors: HIV, malnutrition, genetic, etc em leader Leishmaniasis is part of those diseases which still requires improved control tools. Consequently WHO/TDR research for leishmaniasis has been more and more focusing on the development of new tools such as diagnostic tests, drugs and vaccines. The ongoing effort has already produced significant results. The newly available control tools should allow a scaling up of control activities in priority areas. In anthroponotic foci, the feasibility of getting a strong impact on mortality, morbidity and transmission, is high.

Nitazoxanide Treatment for Giardiasis and Cryptosporidiosis in Children

OBJECTIVE

To review the pharmacology, pharmacokinetics, adverse effects, drug interactions, dosing recommendations, and clinical efficacy of nitazoxanide, a new antiprotozoal/anthelmintic/antibacterial agent.

DATA SOURCES

A MEDLINE search (1966-February 2004) of both human and animal research data published in the English language was conducted.

STUDY SELECTION AND DATA EXTRACTION

All primary and review articles pertaining to the MEDLINE search were reviewed for inclusion. Emphasis was placed on randomized, double-blind, placebo-controlled trials.

DATA SYNTHESIS

Nitazoxanide is approved for the treatment of giardiasis and cryptosporidiosis (first drug approved for the latter indication) in immune-competent children <12 years of age. Most studies in immune-competent patients have reported clinical and parasitologic response rates close to 80% and 70%, respectively, for both indications. Response rates have been lower in immune-compromised patients.

CONCLUSIONS

Nitazoxanide should be available for patients unable to tolerate or adhere to first-line therapy employed for these intestinal protozoa. THIS ARTICLE IS APPROVED FOR CONTINUING EDUCATION CREDIT ACPE UNIVERSAL PROGRAM NUMBER: 407-000-04-014-H01

Single-dose liposomal amphotericin B in the treatment of visceral leishmaniasis in India: a multicenter study

Widespread antimony resistance renders conventional amphotericin B the only option for the treatment of visceral leishmaniasis (VL) in North Bihar, India. Because of its excellent safety profile, a large dose (7.5 mg/kg) of liposomal amphotericin B (L-AmB) was given to each of 203 patients with VL at 4 treatment centers, and the patients were discharged the next day. At initial clinical and parasitological follow-up, performed on day 30 after treatment, evidence of a cure was seen in 195 (96%) of 203 patients (95% CI, 92-98); 4 patients experienced treatment failure. Two patients were lost to follow-up, 2 died (one due to progressive disease and another, 5 months after treatment, due to an unrelated illness), and 12 experienced relapses during follow-up. Thus, 183 patients (90%; 95% CI, 85-94) had obtained final cure 6 months after treatment. Very few adverse events (fever with rigor, in 9.8% of patients) were seen. Single-dose L-AmB (7.5 mg/kg) treatment is safe and effective, and it may be used for the mass treatment of VL in India.

[A comparative study between the efficacy of pentamidine isothionate given in three doses for one week and N-methil-glucamine in a dose of 20mgSbV/day for 20 days to treat cutaneous leishmaniasis]

Seventy-nine patients with cutaneous leishmaniasis were included in this study. The experimental group (n = 38) was treated with pentamidine isothionate in a dose of 4mg/kg/day on alternate days, for one week. The control group (n = 41) was treated with N-methylglucamine in a dose of 20mgSbV/kg/day for 20 days. Twenty-one isolates were identified using monoclonal antibody technique. We characterized Leishmania (Viannia) braziliensis, most frequently. There was a cure rate of 71.05% of the patients in the experimental group and 73.17% in the control group (p = 0.47). We found a statistical significance regarding frequency of ECG alterations between the experimental and control group (p<0.05). In our study pentamidine was as effective as antimonial for the treatment of american cutaneous leishmaniasis. It proved to be a safer drug considering heart toxicity. Moreover, it requires less time to complete the treatment.

Two doses of a lipid formulation of amphotericin B for the treatment of Mediterranean visceral leishmaniasis

To evaluate the efficacy of a short course of a lipid formulation of amphotericin B (L-AmB) for the treatment of Mediterranean visceral leishmaniasis (VL), an open prospective study was conducted. Forty-one children with parasitologically confirmed leishmaniasis received L-AmB, 10 mg/kg daily for 2 days. The comparison groups were 30 children who, in a previous study, were treated with L-AmB, 4 mg/kg daily for 5 days, and 52 children who were treated with meglumine antimoniate. At 6 months after completion of treatment, overall treatment success was noted for 40 of 41 children treated with 2 doses of L-AmB, 27 of 30 children treated with 5 doses of L-AmB, and 47 of 52 children treated with meglumine antimoniate. Abatement of fever, reduction in spleen size, and correction of laboratory parameters occurred more quickly among the children who received 2 doses of L-AmB than among the comparison groups, and the total estimated cost of the 2-dose regimen was also lower than that of the other regimens. Two doses of L-AmB, 10 mg/kg each, is cost-effective therapy for Mediterranean VL in children.

Recent understanding in the treatment of visceral leishmaniasis

Visceral leishmaniasis (VL) is a severe disease associated with infection of the reticuloendothelial system by Leishmania species. The infection is acquired through sandfly bites. Recent large scale epidemics of VL in east Africa and India and the emergence of a HIV epidemic make VL a priority for the World Health Organization. Pentavalent antimonials have been cornerstone of treatment for the last six decades. The appearance of antimonial-resistance and the development of lipid formulations of amphotericin B have changed the pattern of VL treatment. Within the past five years, miltefosine has been demonstrated as the first effective and safe oral treatment against VL. The price of miltefosine is yet to be determined. However, miltefosine will certainly be cheaper than lipid formulations of amphotericin B, which are beyond the financial capacity of the poor countries. Because it can be administered orally, miltefosine is suited for the treatment of large number of patients who get affected during epidemics, particularly in regions where the parasites are resistant to the currently used agents. Here, we recommend different treatment schedules according to the resistance pattern and the region-specific socio-economical and cultural factors.

How better drugs could change kala-azar control. Lessons from a cost-effectiveness analysis

Conditional on correct diagnosis and treatment, current drug regimens for visceral leishmaniasis (VL) will only prevent about 90% of deaths. Furthermore, the cost of pentavalent antimonials, the long duration of the regimen and its parenteral administration are major obstacles for patients. Poor patient compliance and the use of counterfeit drugs contribute to therapeutic failure, amplification of the reservoir and the appearance of drug resistance. We assessed the impact of potential improvements in chemotherapy on the cost-effectiveness of VL test-treatment strategies. Competing test-treatment strategies were compared in a formal decision analysis - from the viewpoint of the clinician facing a VL suspect -, with avoided VL-mortality and cost as outcomes of interest. Sensitivity analysis was done involving the following parameters: efficacy, toxicity and cost of treatment including patient care. When safer and more efficacious drugs are considered, they only result in a more cost-effective strategy if the total cost of treatment falls below US$ 390 per patient. A serological test-treatment strategy remains the optimal choice, also when better drugs become available.

Prophylaxis for human immunodeficiency virus-related Pneumocystis carinii pneumonia: using simulation modeling to inform clinical guidelines

BACKGROUND

Human immunodeficiency virus (HIV)-infected patients receiving highly active antiretroviral therapy (HAART) have experienced a dramatic decrease in Pneumocystis carinii pneumonia (PCP), necessitating reassessment of clinical guidelines for prophylaxis.

METHODS

A simulation model of HIV infection was used to estimate the lifetime costs and quality-adjusted life expectancy (QALE) for alternative CD4 cell count criteria for stopping primary PCP prophylaxis in patients with CD4 cell count increases receiving HAART and alternative agents for second-line PCP prophylaxis in those intolerant of trimethoprim-sulfamethoxazole (TMP/SMX). The target population was a cohort of HIV-infected patients in the United States with initial CD4 cell counts of 350/microL who began PCP prophylaxis after their first measured CD4 lymphocyte count less than 200/microL. Data were from randomized controlled trials and other published literature.

RESULTS

For patients with CD4 cell count increases during HAART, waiting to stop prophylaxis until the first observed CD4 cell count was greater than 300/microL prevented 9 additional cases per 1000 patients and cost $9400 per quality-adjusted life year (QALY) gained compared with stopping prophylaxis at 200/microL. For patients intolerant of TMP/SMX, using dapsone increased QALE by 2.7 months and cost $4500 per QALY compared with no prophylaxis. Using atovaquone rather than dapsone provided only 3 days of additional QALE and cost more than $1.5 million per QALY.

CONCLUSIONS

Delaying discontinuation of PCP prophylaxis until the first observed CD4 cell count greater than 300/microL is cost-effective and provides an explicit "PCP prophylaxis stopping criterion." In TMP/SMX-intolerant patients, dapsone is more cost-effective than atovaquone.

Pricing of drugs and donations: options for sustainable equity pricing

Effective medicines exist to treat or alleviate many diseases which predominate in the developing world and cause high mortality and morbidity rates. Price should not be an obstacle preventing access to these medicines. Increasingly, drug donations have been established by drug companies, but these are often limited in time, place or use. Measures exist which are more sustainable and will have a greater positive impact on people's health. Principally, these are encouraging generic competition; adopting into national legislation and implementing TRIPS safeguards to gain access to cheaper sources of drugs; differential pricing; creating high volume or high demand through global and regional procurement; and supporting the production of quality generic drugs by developing countries through voluntary licenses if needed, and facilitating technology transfer.

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.

A single high dose treatment of kala-azar with Ambisome (amphotericin B lipid complex): a pilot study

Thirty four patients with parasitologically confirmed visceral leishmaniasis were divided randomly into two groups of 17. Group A received Ambisome (amphotericin B lipid complex) at a dose of 15mg/kg body weight infused over 2h as a single dose; patients in group B received amphotericin B deoxycholate at a dose of 1mg/kg body infused for 2h for 20days. All 34 patients had a clinical, parasitological and ultimate cure. Ambisome was much better tolerated than amphotericin B, and adverse events were fewer in the Ambisome group. It was concluded that, if the cost of Ambisome were reduced, it would be a suitable first line drug. A longer study comparing three regimes of Ambisome: 15mg/kg body weight, 11mg/kg body weight and 7.5mg/kg body weight, should be undertaken.

[Drugs for 'neglected diseases': a bitter pill]

Neglected diseases are diseases restricted to poor areas; diseases for which there exist no commercial incentives to invest in the development of new treatments. Patients suffering from these diseases often have no access to essential drugs; this can be a matter of life and death. Lack of research and patent protection play a crucial role. Both are cost driven; greed in the West curtails the availability of life-saving drugs for all. Treatment options for trypanosomiasis and visceral leishmaniasis are lacking. It is recommended that drugs for the treatment of 'neglected diseases' be developed via a centralised, public approach that is not based on profit, rather than leaving it to free enterprise.

Short-course, cost-effective treatment with amphotericin B-fat emulsion cures visceral leishmaniasis

Although short-course therapy with new lipid formulations of amphotericin B represents an advance over lengthy traditional treatments in visceral leishmaniasis (kala-azar), high cost has rendered these agents largely irrelevant in developing countries where the disease is endemic. Therefore, we tested standard amphotericin B deoxycholate mixed with a commercial fat emulsion as short-course treatment for Indian visceral leishmaniasis in Bihar in 1997/98. Seventy children and adults with splenic aspirate-documented infection, 23 of whom had failed prior antimony (Sb) therapy, received 5 alternate-day infusions of 2 mg/kg. Apparent cure, which required a parasite-free splenic aspirate smear, was assessed 20 days after treatment (day 30); definitive cure was determined at 6 months. Other than anticipated infusion-related fever and/or chills, treatment was safe and well tolerated. One patient required dose modification because of mild, reversible renal insufficiency. Sixty-nine patients (98.6%, CI 92.3-100%) had apparent cures; during follow-up, there were 4 treatment failures (relapses, 3; unrelated death, 1), yielding definitive cures in 65 of 70 patients (92.9%, CI 84.1-97.6%). Including retreatment costs for patients in Bihar (who now often fail initial Sb therapy), the final per patient cost of the tested regimen (US $260) was 59% and 43% less than treatment with Sb or conventional amphotericin B alone, respectively. Short-course treatment with amphotericin B-fat emulsion is active, cost-effective treatment for patients with visceral leishmaniasis including those with Sb-unresponsive infection.