Control programs for strongyloidiasis in areas of high endemicity: an economic analysis of different approaches.

BACKGROUND: Implementation of control programmes for Strongyloides stercoralis infection is among the targets of the World Health Organization Roadmap to 2030. Aim of this work was to evaluate the possible impact in terms of economic resources and health status of two different strategies of preventive chemotherapy (PC) compared to the current situation (strategy A, no PC): administration of ivermectin to school-age children (SAC) and adults (strategy B) versus ivermectin to SAC only (strategy C). METHODS: The study was conducted at the IRCCS Sacro Cuore Don Calabria hospital, Negrar di Valpolicella, Verona, Italy, at the University of Florence, Italy, and at the WHO, Geneva, Switzerland, from May 2020 to April 2021. Data for the model were extracted from literature. A mathematical model was developed in Microsoft Excel to assess the impact of strategies B and C in a standard population of 1 million subjects living in a strongyloidiasis endemic area. In a case base scenario, 15% prevalence of strongyloidiasis was considered; the 3 strategies were then evaluated at different thresholds of prevalence, ranging from 5 to 20%. The results were reported as number of infected subjects, deaths, costs, and Incremental-Effectiveness Ratio (ICER). A 1-year and a 10-year horizons were considered. RESULTS: In the case base scenario, cases of infections would reduce dramatically in the first year of implementation of PC with both strategy B and C: from 172 500 cases to 77 040 following strategy B and 146 700 following strategy C. The additional cost per recovered person was United States Dollar (USD) 2.83 and USD 1.13 in strategy B and C, respectively, compared to no treatment in the first year. For both strategies, there was a downtrend in costs per recovered person with increasing prevalence. The number of adverted deaths was larger for strategy B than C, but cost to advert one death was lower for strategy C than B. CONCLUSIONS: This analysis permits to estimate the impact of two PC strategies for the control of strongyloidiasis in terms of costs and adverted infections/deaths. This could represent a basis on which each endemic country can evaluate which strategy can be implemented, based on available funds and national health priorities.

Integrating testing for chronic strongyloidiasis within the Indigenous adult preventive health assessment system in endemic communities in the Northern Territory, Australia: An intervention study.

BACKGROUND: The life-threatening clinical manifestations of strongyloidiasis are preventable with early detection and effective treatment. The aim of this study was to assess if there was an increase to the number and proportion of persons tested for chronic strongyloidiasis, as a result of integrating Strongyloides stercoralis serology into the existing preventive health assessment system in four Aboriginal health services in endemic communities. METHODOLOGY: A prospective, longitudinal, before-and-after intervention study was conducted in four Aboriginal health services in remote endemically infected communities in the Northern Territory, Australia, from July 2012 to December 2016. The electronic patient information and recall systems enabled the integration of Strongyloides stercoralis serology into the adult preventive health assessment. Strongyloides reports for each health service were extracted half-yearly to examine the number and proportion of persons tested for chronic strongyloidiasis during the study and to measure the effect of the intervention. PRINCIPAL FINDINGS: The number and proportion of persons tested increased significantly during the study. From a total resident population of 3650 Indigenous adults over 15 years of age, 1686 persons (47.4%) were tested. The percentage of adults who had at least one serology test increased in all four health services to between 41% (446/1086) and 81.9% (172/210). Of the 1686 persons tested, 680 positive cases of chronic strongyloidiasis (40.3%) were identified. CONCLUSIONS/SIGNIFICANCE: This population health systems intervention increased the number and proportion of persons tested for chronic strongyloidiasis in four health services in endemically infected communities. This intervention is relevant to other health services with high-risk populations.

Impact of the health education and preventive equipment package (HEPEP) on prevention of Strongyloides stercoralis infection among rural communities in Northeast Thailand: a cluster randomized controlled trial.

BACKGROUND: Strongyloidiasis is prevalent in northeast Thailand. This study aimed to evaluate the impact of the Health Education and Preventive Equipment Package (HEPEP), a package we developed to improve awareness and aid in the prevention of Strongyloides stercoralis infection among rural communities in northeast Thailand. METHODS: This was an intervention trial conducted in 12 villages (six interventions and six controls) in rural areas of northeast Thailand from March 2016 to September 2017. Single stool sample was collected from each participant and examined using agar plate culture (APC) technique. Each participant was interviewed using a pre-tested questionnaire, treated with single dose of ivermectin (200 µg/Kg), and allocated to either the intervention or control group. Members of the intervention group were given "Practices to Prevent Strongyloidiasis" poster and vinyl boards containing information aimed at raising awareness of S. stercoralis and strongyloidiasis. In addition, they were given a poster lecture regarding the lifecycle of S. stercoralis before being treated with ivermectin. Aside from that, they were also given a protective equipment package. Monthly refresher courses were provided by village health volunteers (VHVs) regarding the health information they had received and proper equipment usage. The control group, on the other hand, was only provided with a five-minute lecture regarding strongyloidiasis. Assessment of new infection was conducted 3 months later in 327 and 318 participants in the intervention group and control group, respectively. RESULTS: The HEPEP had 41% greater efficacy in preventing S. stercoralis infection in the intervention group than the measures taken in the control group (adjusted Odds Ratio (aOR) = 0.59; 95%CI: 0.41 to 0.85, P-value = 0.005). The intervention group also scored significantly higher on all aspects of a test of S. stercoralis knowledge compared with the control group (mean difference (mean dif.) = 2.89, P-value = < 0.05). CONCLUSIONS: The HEPEP was the first model that has been found to be effective in controlling of S. stercoralis in rural communities in the northeast Thailand. The results should encourage policy makers and public health personnel to improve control programs, as well as health promotion, with regard to parasites. TRIAL REGISTRATION: Thai Clinical Trials Registry (TCTR), Medical Research Foundation of Thailand, Medical Research Network of the Consortium of Thai Medical Schools: MedResNet (Thailand) (identification number: TCTR20180404002 ) Registered 4 April 2018 (retrospectively registered).

Serologic Monitoring of Public Health Interventions against Strongyloides stercoralis.

Northwestern Argentina is endemic for soil-transmitted helminths, and annual deworming programs are carried out in prioritized areas. High prevalence of Strongyloides stercoralis was reported in this area; therefore, control programs including ivermectin are being evaluated. The NIE-enzyme linked immunosorbent assay (ELISA) was used for this purpose. In this community trial, two groups of patients, classified according to housing and living conditions were evaluated. Simultaneous with baseline survey, Group 1 was moved to new households with access to improved water and sanitation facilities (W and S), where deworming (MDA, massive drug administration) took place within 1 month; whereas Group 2 received MDA but remained living with unimproved W and S. The mean time interval between baseline and the follow-up was 331 days for Group 1 and 508 for Group 2. Anti-NIE levels were measured for each individual before and after interventions and follow-up optical density (OD) ratios were calculated to quantify the variation. A significant decrease of the anti-NIE levels between baseline and follow-up was observed in both groups. Nonetheless, the number of patients that achieved the cure criteria (OD ratio < 0.6) was higher in Group 1 than Group 2 with values of 72.7% (24/33) and 45.0% (18/40), respectively (P = 0.0197). Our results support the conclusion that a combined intervention including deworming and improvements in life conditions is more effective, in terms of the proportion of subjects cured than deworming alone. Furthermore, we found that NIE-ELISA is a useful test for assessing the response to treatment and to evaluate the outcome of control intervention programs.

The cost-effectiveness of ivermectin vs. albendazole in the presumptive treatment of strongyloidiasis in immigrants to the United States.

The presumptive treatment of parasitosis among immigrants with albendazole has been shown to save both money and lives, primarily via a reduction in the burden of Strongyloides stercoralis. Ivermectin is more effective than albendazole, but is also more expensive. This coupled with confusion surrounding the cost-effectiveness of guiding therapy based on eosinophil counts has led to disparate practices. We used the newly arrived year 2000 immigrant population as a hypothetical cohort in a decision analysis model to examine the cost-effectiveness of various interventions to reduce parasitosis among immigrants. When the prevalence of S. stercoralis is greater than 2%, the incremental cost-effectiveness ratios of all presumptive treatment strategies were similar. Ivermectin is associated with an incremental cost-effectiveness ratio of 1700 dollars per QALY gained for treatment with 12 mg ivermectin relative to 5 days of albendazole when the prevalence is 10%. Any presumptive treatment strategy is cost-effective when compared with most common medical interventions.

Opportunistic strongyloidiasis in renal transplant recipients.

Eight patients with severe strongyloidiasis complicating renal transplantation are reported. Twenty-one additional cases from the English-language literature are reviewed. In this setting, systemic strongyloidiasis is an often baffling illness involving multiple organ systems that is frequently complicated by serious bacterial infection. Bacteremia, meningitis, urinary tract infection, and pneumonia resulting from enteric organisms are common. In order to make the diagnosis, larvae must be sought by direct microscopy of stool, upper intestinal fluid, sputum, urine, or biopsy specimens. Treatment with oral thiabendazole in prolonged or repeated courses is recommended. Effective parenteral therapy is not available. Following treatment, previously parasitized patients must be tested at regular intervals to detect therapeutic failure or reinfection. Screening of patients awaiting renal transplantation for chronic intestinal strongyloidiasis is suggested. Improvement of the observed 52% mortality will depend upon heightened awareness by physicians caring for renal transplant candidates, and upon improved therapeutic regimens.