Mass Administration of Ivermectin for the Elimination of Onchocerciasis Significantly Reduced and Maintained Low the Prevalence of Strongyloides stercoralis in Esmeraldas, Ecuador

Prevalence of Strongyloides stercoralis and other helminths in four districts of Madagascar

BACKGROUND

Estimation of prevalence of Strongyloides stercoralis infection is required in endemic areas, in order to identify areas in need of control programmes. Data on prevalence of strongyloidiasis in Madagascar are scant. Aim of this work was to estimate prevalence of S. stercoralis in four districts of Madagascar.

METHODS

Fecal and serum samples collected in the context of a previous study on schistosomiasis were tested with S. stercoralis real-time PCR and serology, respectively. A multiplex real-time PCR for Ascaris lumbricoides, Ancylostoma duodenalis, Necator americanus, and Trichuris trichiura was done on fecal samples collected in the areas demonstrating higher prevalence of strongyloidiasis. Comparisons between proportions were made using Fisher exact test, with false discovery rate correction used for post-hoc comparisons. A multivariable Firth logistic regression model was used to assess potential risk factors for S. stercoralis infection.

RESULTS

Overall, 1775 serum samples were tested, of which 102 of 487 (20.9%) and 104 of 296 (35.2%) were serological-positive in Marovoay and in Vatomandry districts (both coastal areas), respectively, compared to 28 of 496 (5.6%) and 30 of 496 (6.1%) in Tsiroanomandidy and in Ambositra districts (both highlands), respectively (adj. p < 0.001). PCR for S. stercoralis was positive in 15 of 210 (7.1%) and in 11 of 296 (3.7%) samples from Marovoay from Vatomandry, respectively, while was negative for all samples tested in the other two districts. High prevalence of A. lumbricoides (45.9%), hookworm (44.6%) and T. trichiura (32.1%) was found in Vatomandry. In the multivariable analysis, strongyloidiasis was associated with hookworm infection. Hookworm infection was also associated with male sex and lower education level.

CONCLUSIONS

S. stercoralis prevalence proved higher in coastal areas compared to highlands. Different climatic conditions may explain this distribution, along with previous rounds of anthelminthics distributed in the country, which may have reduced the parasite load in the population. The high prevalence of the other soil-transmitted helminths (STH) in Vatomandry was unexpected, given the good coverage with benzimidazole in control campaigns. Further studies are needed to explore the risk factors for STH and S. stercoralis infections in Madagascar, in order to align with the WHO recommendations.

Effectiveness of ivermectin mass drug administration in the control of soil-transmitted helminth infections in endemic populations: a systematic review and meta-analysis

BACKGROUND

Current soil-transmitted helminth (STH) control guidelines endorse the use of albendazole or mebendazole for school-based targeted preventive chemotherapy (PC), yet their reduced efficacy against Strongyloides stercoralis and Trichuris trichiura presents significant limitations. Emerging evidence indicates that community-wide PC [or mass drug administration (MDA)] using ivermectin, commonly used in other neglected tropical disease (NTD) control programs, may play an important role in controlling these parasites. We conducted a systematic review and meta-analysis to evaluate the effectiveness of ivermectin PC in reducing STH prevalence in endemic populations.

METHODS

We searched Pubmed, EMBASE, and Web of Science on February 14, 2023, for studies that investigated the effectiveness of ivermectin PC, either alone or in combination with other anthelmintic drugs, on STH infections, and provided a measure of STH prevalence before and after PC. We calculated pooled prevalence reductions for each STH using random-effects meta-analyses. Our protocol is available on PROSPERO (registration number CRD42023401219).

RESULTS

A total of 21 were eligible for the systematic review, of which 15 were eligible for meta-analysis. All studies delivered ivermectin through MDA. The pooled prevalence reduction of S. stercoralis following MDA with ivermectin alone was 84.49% (95% CI 54.96-94.66) across five studies and 81.37% (95% CI 61.62-90.96) across seven studies with or without albendazole. The prevalence reduction of T. trichiura was 49.93% (95% CI 18.23-69.34) across five studies with ivermectin alone, and 89.40% (95% CI 73.66-95.73) across three studies with the addition of albendazole. There was high heterogeneity for all syntheses (I2 > 65%).

CONCLUSIONS

This study underscores the key role of ivermectin-based MDA in addressing limitations in current global STH guidelines in terms of limited efficacy against S. stercoralis and T. trichiura. Based on these findings, revising international STH guidelines to include ivermectin is a promising option to progress the control and eventual elimination of STHs and other NTDs.

Progress towards the implementation of control programmes for strongyloidiasis in endemic areas: estimation of number of adults in need of ivermectin for strongyloidiasis

The World Health Organization has started a process to issue guidelines for the control of strongyloidiasis. The guidelines might recommend to implement preventive chemotherapy (PC) at community level (i.e. to all individuals above 5 years of age), over a defined prevalence threshold. We previously estimated the number of school-age children (SAC) who would need PC. Here we estimate the number of people above 15 years of age who might be included in PC for strongyloidiasis. Based on previous Strongyloides prevalence estimates and on countries' age distribution, we retrieved the number of adults in need of PC. We then subtracted the number of people already involved in ivermectin mass distribution for the elimination of onchocerciasis and lymphatic filariasis and people living in countries where Loa loa is endemic. The number of adults to be involved in PC was estimated at 905.4 (95% confidence interval (CI): 520.6-1177.2), 660.2 (95% CI: 512.7-1214.9), and 512.1 (95% CI: 276-719.4) million people, when the strongyloidiasis prevalence threshold for implementing PC was set to 10%, 15% and 20%, respectively. Estimates at country level are also provided.These estimates might help endemic countries wishing to implement PC for strongyloidiasis to allocate resources to include adults in addition to SAC in control programmes. This article is part of the Theo Murphy meeting issue 'Strongyloides: omics to worm-free populations'.

The transmission dynamics of Strongyloides stercoralis and the impact of mass drug administration

The epidemiology of Strongyloides stercoralis is briefly reviewed with an emphasis on cross section and longitudinal studies of infection prevalence stratified by age, performance of different diagnostic tools, mass drug administration (MDA) impact and estimates of key population parameters within the complex life cycle of the parasite that determine transmission intensity and response to control measures. The paucity of studies is highlighted, and gaps in current knowledge identified about the population biology of this very prevalent infection in tropical and sub-tropical regions around the world. A stochastic individual based stochastic model is described in part to highlight gaps in knowledge. The impact of repeated MDA is simulated to illustrate some aspects of transmission dynamics of this helminth infection. Specifically, the impact and bounce back times in either the intervals between treatment rounds, or post the cessation of treatment, depend critically on the magnitude of two distinct components of the basic reproductive number R0. The absence of data on these key components is highlighted, as is the value of studies of longitudinal cohorts of people in regions of endemic infection post rounds of MDA to record how infection levels bounce back post treatment at individual and population levels of study. This article is part of the Theo Murphy meeting issue 'Strongyloides: omics to worm-free populations'.

Effectiveness of one and two doses of ivermectin mass drug administration in reducing the prevalence and intensity of soil-transmitted helminth (STH) infections in Western Province, Solomon Islands: a cluster-randomised, before-after analysis

Background

Ivermectin mass drug administration (MDA) is effective for controlling onchocerciasis and scabies, with evidence supporting its role in some species of soil-transmitted helminth (STH) infections. In the context of RISE, a cluster-randomised trial for scabies, this study evaluated the effectiveness of ivermectin MDA in reducing STH burden in the Western Province of Solomon Islands.

Methods

Twenty villages were randomised 1:1 to receive ivermectin MDA as one dose (IVM-1) or two doses (IVM-2) for scabies. The effectiveness of one and two doses in reducing STH prevalence and intensity was evaluated before (May 2019) and 21 months after (February 2021) MDA in May 2019. All residents aged 12 months or older in the study villages were eligible to participate and provide stool specimens. Species-specific STH infection and intensity were assessed using quantitative PCR. We compared prevalence and intensity of infection between baseline and 21 months in each intervention arm individually using cluster-level analysis (adjusted for clustering) and individual-level analysis (adjusted for sex, age, and clustering). The primary outcomes were the prevalence risk difference (RD) from the cluster-level analysis, and the change in adjusted odds of infection from the individual-level analysis. Secondary outcomes included change in incident rates of mean eggs per gram (epg) of stool from baseline to 21 months, relative risk difference in prevalence and relative change in odds of infection between arms at 21 months. Sex data (male/female) were self-reported.

Findings

Overall, STH infection was assessed in 830 participants from 18 villages at baseline and 1172 from 20 villages at follow-up. Females represented 58% (n = 478) of the sample at baseline and 59% (n = 690) at follow-up. We observed a reduction in Strongyloides spp. prevalence following two doses of ivermectin MDA in the cluster-level analysis from 7.0% (32/458 participants) to 1.2% (8/674 participants), corresponding to a RD of -0.07 (95% CI -0.14 to -0.01, p = 0.036), and in the individual-level analysis (OR 0.11, 95% CI 0.04-0.33, p < 0.001). T. trichiura prevalence decreased following one dose from 19.4% (74/372 participants) to 11.7% (56/505 participants) (OR 0.44, 95% CI 0.26-0.73, p = 0.0040), while egg count reduced in both arms (IVM-1: IRR 0.28, 95% CI 0.11-0.70, p = 0.0070; IVM-2: IRR 0.18, 95% CI 0.08-0.40, p < 0.001), in the individual-level analysis. We did not detect a significant difference in effect measures between the one- and two-dose arms for any species after 21 months.

Interpretation

Our study highlights the long-term benefits of ivermectin MDA in reducing the burden of Strongyloides spp. and T. trichiura. STH control programs should leverage the geographical overlap of NTDs, existing drug distribution channels, and broad-spectrum agents.

Funding

The National Health and Medical Research Council of Australia.

Impact of preventive chemotherapy on Strongyloides stercoralis: A systematic review and meta-analysis

BACKGROUND

Strongyloides stercoralis is a neglected soil-transmitted helminth (STH) that leads to significant morbidity in endemic populations. Infection with this helminth has recently been recognised by the World Health Organization (WHO) as a major global health problem to be addressed with ivermectin preventive chemotherapy, and therefore, there is now, the need to develop guidelines for strongyloidiasis control that can be implemented by endemic countries. This study aimed to evaluate the impact of ivermectin preventive chemotherapy (PC) on S. stercoralis prevalence in endemic areas to generate evidence that can inform global health policy.

METHODOLOGY/PRINCIPAL FINDINGS

This study was a systematic review and meta-analysis. We searched PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and LILACS for literature published between 1990 and 2022 and reporting prevalence of S. stercoralis before and after PC with ivermectin, administered either at school or at community level. The search strategy identified 933 records, eight of which were included in the meta-analysis. Data extraction and quality assessment were carried out by two authors. Meta-analysis of studies based on fecal testing demonstrated a significant reduction of S. stercoralis prevalence after PC: prevalence Risk Ratio (RR) 0.18 (95% CI 0.14-0.23), I2 = 0. A similar trend was observed in studies that used serology for diagnosis: RR 0.35 (95% CI 0.26-0.48), I2 = 4.25%. A sensitivity analysis was carried out for fecal tests where low quality studies were removed, confirming a post-intervention reduction in prevalence. The impact of PC could not be evaluated at different time points or comparing annual vs biannual administration due to insufficient data.

CONCLUSIONS/SIGNIFICANCE

Our findings demonstrate a significant decrease of S. stercoralis prevalence in areas where ivermectin PC has taken place, supporting the use of ivermectin PC in endemic areas.

Accuracy, acceptability, and feasibility of diagnostic tests for the screening of Strongyloides stercoralis in the field (ESTRELLA): a cross-sectional study in Ecuador

BACKGROUND

WHO recommends the implementation of control programmes for strongyloidiasis, a neglected tropical disease caused by Strongyloides stercoralis. Specific recommendations on the diagnostic test or tests to be used for such programmes have yet to be defined. The primary objective of this study was to estimate the accuracy of five tests for strongyloidiasis. Secondary objectives were to evaluate acceptability and feasibility of use in an endemic area.

METHODS

The ESTRELLA study was a cross-sectional study for which we enrolled school-age children living in remote villages of Ecuador. Recruitment took place in two periods (Sept 9-19, 2021, and April 18-June 11, 2022). Children supplied one fresh stool sample and underwent blood collection via finger prick. Faecal tests were a modified Baermann method and an in-house real-time PCR test. Antibody assays were a recombinant antigen rapid diagnostic test; a crude antigen-based ELISA (Bordier ELISA); and an ELISA based on two recombinant antigens (Strongy Detect ELISA). A Bayesian latent class model was used to analyse the data.

FINDINGS

778 children were enrolled in the study and provided the required samples. Strongy Detect ELISA had the highest sensitivity at 83·5% (95% credible interval 73·8-91·8), while Bordier ELISA had the highest specificity (100%, 99·8-100). Bordier ELISA plus either PCR or Baermann had the best performance in terms of positive and negative predictive values. The procedures were well accepted by the target population. However, study staff found the Baermann method cumbersome and time-consuming and were concerned about the amount of plastic waste produced.

INTERPRETATION

The combination of Bordier ELISA with either faecal test performed best in this study. Practical aspects (including costs, logistics, and local expertise) should, however, also be taken into consideration when selecting tests in different contexts. Acceptability might differ in other settings.

FUNDING

Italian Ministry of Health.

TRANSLATION

For the Spanish translation of the abstract see Supplementary Materials section.

Ivermectin inhibits tumor metastasis by regulating the Wnt/β-catenin/integrin β1/FAK signaling pathway

Tumor metastasis is the major cause of cancer mortality; therefore, it is imperative to discover effective therapeutic drugs for anti-metastasis therapy. In the current study, we investigated whether ivermectin (IVM), an FDA-approved antiparasitic drug, could prevent cancer metastasis. Colorectal and breast cancer cell lines and a cancer cell-derived xenograft tumor metastasis model were used to investigate the anti-metastasis effect of IVM. Our results showed that IVM significantly inhibited the motility of cancer cells in vitro and tumor metastasis in vivo. Mechanistically, IVM suppressed the expressions of the migration-related proteins via inhibiting the activation of Wnt/β-catenin/integrin β1/FAK and the downstream signaling cascades. Our findings indicated that IVM was capable of suppressing tumor metastasis, which provided the rationale on exploring the potential clinical application of IVM in the prevention and treatment of cancer metastasis.

A systematic review and an individual patient data meta-analysis of ivermectin use in children weighing less than fifteen kilograms: Is it time to reconsider the current contraindication?

BACKGROUND

Oral ivermectin is a safe broad spectrum anthelminthic used for treating several neglected tropical diseases (NTDs). Currently, ivermectin use is contraindicated in children weighing less than 15 kg, restricting access to this drug for the treatment of NTDs. Here we provide an updated systematic review of the literature and we conducted an individual-level patient data (IPD) meta-analysis describing the safety of ivermectin in children weighing less than 15 kg.

METHODOLOGY/PRINCIPAL FINDINGS

A systematic review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) for IPD guidelines by searching MEDLINE via PubMed, Web of Science, Ovid Embase, LILACS, Cochrane Database of Systematic Reviews, TOXLINE for all clinical trials, case series, case reports, and database entries for reports on the use of ivermectin in children weighing less than 15 kg that were published between 1 January 1980 to 25 October 2019. The protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO): CRD42017056515. A total of 3,730 publications were identified, 97 were selected for potential inclusion, but only 17 sources describing 15 studies met the minimum criteria which consisted of known weights of children less than 15 kg linked to possible adverse events, and provided comprehensive IPD. A total of 1,088 children weighing less than 15 kg were administered oral ivermectin for one of the following indications: scabies, mass drug administration for scabies control, crusted scabies, cutaneous larva migrans, myiasis, pthiriasis, strongyloidiasis, trichuriasis, and parasitic disease of unknown origin. Overall a total of 1.4% (15/1,088) of children experienced 18 adverse events all of which were mild and self-limiting. No serious adverse events were reported.

CONCLUSIONS/SIGNIFICANCE

Existing limited data suggest that oral ivermectin in children weighing less than 15 kilograms is safe. Data from well-designed clinical trials are needed to provide further assurance.

Metabolism and interactions of Ivermectin with human cytochrome P450 enzymes and drug transporters, possible adverse and toxic effects

The review presents metabolic properties of Ivermectin (IVM) as substrate and inhibitor of human P450 (P450, CYP) enzymes and drug transporters. IVM is metabolized, both in vivo and in vitro, by C-hydroxylation and O-demethylation reactions catalyzed by P450 3A4 as the major enzyme, with a contribution of P450 3A5 and 2C9. In samples from both in vitro and in vivo metabolism, a number of metabolites were detected and as major identified metabolites were 3″-O-demethylated, C4-methyl hydroxylated, C25 isobutyl-/isopropyl-hydroxylated, and products of oxidation reactions. Ivermectin inhibited P450 2C9, 2C19, 2D6, and CYP3A4 with IC₅₀ values ranging from 5.3 μM to no inhibition suggesting that it is no or weak inhibitor of the enzymes. It is suggested that P-gp (MDR1) transporter participate in IVM efflux at low drug concentration with a slow transport rate. At the higher, micromolar concentration range, which saturates MDR1 (P-gp), MRP1, and to a lesser extent, MRP2 and MRP3 participate in IVM transport across physiological barriers. IVM exerts a potent inhibition of P-gp (ABCB1), MRP1 (ABCC1), MRP2 (ABCC2), and BCRP1 (ABCG2), and medium to weak inhibition of OATP1B1 (SLC21A6) and OATP1B3 (SLCOB3) transport activity. The metabolic and transport properties of IVM indicate that when IVM is co-administered with other drugs/chemicals that are potent inhibitors/inducers P4503A4 enzyme and of MDR1 (P-gp), BCRP or MRP transporters, or when polymorphisms of the drug transporters and P450 3A4 exist, drug–drug or drug–toxic chemical interactions might result in suboptimal response to the therapy or to toxic effects.

Impact of Community Treatment With Ivermectin for the Control of Scabies on the Prevalence of Antibodies to Strongyloides stercoralis in Children

The prevalence of antibodies to Strongyloides stercoralis was measured in 0-12-year-olds using a bead-based immunoassay before and after ivermectin mass drug administration (MDA) for scabies in the Solomon Islands. Seroprevalence was 9.3% before and 5.1% after MDA (P = .019), demonstrating collateral benefits of ivermectin MDA in this setting.

World Gastroenterology Organisation Global Guidelines: Management of Strongyloidiasis February 2018-Compact Version>

Strongyloides stercoralis is a soil-transmitted helminth, but it has a unique life cycle that can be completed in the human host, in a process known as autoinfection. Worldwide, the burden of disease is substantial (300 to 400 million infections). Strongyloidiasis is mainly prevalent in the tropics and subtropics, but there is as yet no global public health strategy for controlling the parasite.

The global progress of soil-transmitted helminthiases control in 2020 and World Health Organization targets for 2030

Soil-transmitted helminth (STH) infections are the most widespread of the neglected tropical diseases, primarily affecting marginalized populations in low- and middle-income countries. More than one billion people are currently infected with STHs. For the control of these infections, the World Health Organization (WHO) recommends an integrated approach, which includes access to appropriate sanitation, hygiene education, and preventive chemotherapy (i.e., large-scale, periodic distribution of anthelmintic drugs). Since 2010, WHO has coordinated two large donations of benzimidazoles to endemic countries. Thus far, more than 3.3 billion benzimidazole tablets have been distributed in schools for the control of STH infections, resulting in an important reduction in STH-attributable morbidity in children, while additional tablets have been distributed for the control of lymphatic filariasis. This paper (i) summarizes the progress of global STH control between 2008 to 2018 (based on over 690 reports submitted by endemic countries to WHO); (ii) provides regional and country details on preventive chemotherapy coverage; and (iii) indicates the targets identified by WHO for the next decade and the tools that should be developed to attain these targets. The main message is that STH-attributable morbidity can be averted with evidence-informed program planning, implementation, and monitoring. Caution will still need to be exercised in stopping control programs to avoid any rebound of prevalence and loss of accrued morbidity gains. Over the next decade, with increased country leadership and multi-sector engagement, the goal of eliminating STH infections as a public health problem can be achieved.

Mapping the Prevalence of Strongyloides stercoralis Infection in Ecuador: A Serosurvey

Data on the prevalence of strongyloidiasis in Ecuador are patchy. The aim of this study was to document the presence of Strongyloides stercoralis infection in rural communities of different provinces of Ecuador. We tested 1,418 serum samples stored at the biobank of the Central University of Ecuador, Quito, with an ELISA test for Strongyloides. The samples had been collected in eight different provinces of Ecuador. Two hundred ninety-four samples (20.7%) were positive, and Jipijapa, Manabí Province, was the site with the largest proportion of positive samples (66.7%). Further surveys aimed at estimating the prevalence of the infection should be carried out in areas where the infection seems highly prevalent, and ad hoc control measures should be adopted.

Update on the major imported helminth infections in travelers and migrants

Helminth infections cause considerable morbidity worldwide and may be frequently underdiagnosed especially in areas of lower endemicity. Patients may harbor latent infections that may become symptomatic years or decades after the initial exposure and timely diagnosis may be critical to prevent complications and improve outcomes. In this context, disease in special populations, such as immunosuppressed patients, may be of particular concern. Heightened awareness and recent diagnostic developments may contribute to the correct management of helminth infections in nonendemic regions. A review of the main helminth infections in travelers and migrants (strongyloidiasis, taeniasis-neurocysticercosis and schistosomiasis) is presented, focusing on epidemiology, developments in diagnosis, treatment and prevention.

Community Epidemiology Approach to Parasitic Infection Screening in a Remote Community in Ecuador

The Awa indigenous people of Ecuador live in remote areas and were included in health programs only recently. The first screening for parasitic infections in the Awa communities was implemented in the context of community epidemiology. During the site visits in each community, the health-care staff collected the samples for stool microscopy and serology for Strongyloides. A total of 705 individuals consented for the study, representing 40% of the Awa population living in the targeted communities; 184 (26%) participants supplied a stool sample. Giardia intestinalis was found in about 11% of samples. Prevalence of Ascaris lumbricoides and Trichuris trichiura was 54.9% and 36.9%, respectively. No hookworm eggs were found. In addition, Strongyloides stercoralis larvae were found in eight individuals (4.3%), whereas serology was positive in 22.7% of the individuals tested. The community-based approach resulted in an impressive participation. There was a high prevalence of parasites associated with relevant morbidity.

Overcoming challenges in the diagnosis and treatment of parasitic infectious diseases in migrants

Introduction: Recent increases in population movements have created novel health challenges in many areas of the World, and health policies have been adapted accordingly in several countries. However, screening guidelines for infectious diseases are not standardized and generally do not include comprehensive screening for parasitic infections.Areas covered: Malaria, Chagas disease, leishmaniasis, amebiasis, filariases, strongyloidiasis, and schistosomiasis are reviewed, focusing on the challenges posed for their diagnosis and management in vulnerable populations such as migrants. The methodology included literature searches in public databases such as PubMed.gov and Google Scholar and search of the US National Library of Medicine online database of privately and publicly funded clinical studies (ClinicalTrials.gov) until November 2019.Expert opinion: Parasitic infections which may remain asymptomatic for prolonged periods, leading to chronic infection and complications, and/or may be transmitted in non-endemic areas are ideal candidates for screening. Proposed strategies to improve diagnosis in vulnerable groups such as migrants include facilitating access to healthcare in a multi-dimensional manner considering location, individual characteristics, and timing. Limitations and availability of specific diagnostic techniques should be addressed and focus on drug and vaccine development for these neglected infections should be prioritized through collaborative initiatives with public disclosure of results.

Long-Term Outcomes of a Cohort of Hypertensive Subjects in Rural Ecuador

BACKGROUND

In contrast with the abundance of global epidemiological descriptive data on cardiovascular diseases and their risk factors, information on the outcomes of real populations prospectively followed up in their life and care settings is much rarer, especially in low-income countries.

OBJECTIVES

This study sought to evaluate the feasibility and the overall results of a hypertension control program, based mainly on a network of community nonprofessional health promoters, in the poor rural region of Borbon (Ecuador).

METHODS

This is a prospective cohort study describing the results of a program of hypertension diagnosis, treatment and follow-up from 2004 to 2015 in the area, carried out mainly by the health promoters.

RESULTS

The number of hypertensive patients identified and followed over the years increased from 1,024 in 2004 to 1,733 in 2015. The percentage of patients with no visits during a year was reduced to <10%, whereas the proportion of hypertensive subjects attending all 4 scheduled annual checks approached and, in some years, exceeded 50%. From 2004 to 2015, the proportion of patients at high or very high cardiovascular risk progressively decreased from 26.6% in 2004 to 17.5% in 2015 (p for trend <0.01), whereas the proportion of hypertensive patients at low or very low risk increased from 30.4% in 2004 to 45.0% in 2015 (p for trend <0.01).

CONCLUSIONS

In a poor, disadvantaged area, a strategy of control mainly based on the involvement and responsibility of community health promoters (with health professionals as supporters more than direct actors) can achieve adequate follow-up of the population of hypertensive patients and improve their global cardiovascular risk level.

Strongyloidiasis: A Neglected Tropical Disease

Most of the 30 to 100 million people infected with Strongyloides stercoralis have subclinical (or asymptomatic) infections. These infections are commonly chronic and longstanding. A change in immune status can increase parasite numbers, leading to hyperinfection syndrome, dissemination, and death if unrecognized. The use of corticosteroids and HTLV-1 infection are most commonly associated with the hyperinfection syndrome. Strongyloides adult parasites reside in the small intestine and induce immune responses that are like other nematodes. Definitive diagnosis of S stercoralis infection is based on stool examinations for larvae. S stercoralis remains largely neglected.

Soil-Transmitted Helminthiasis in Children from a Rural Community Taking Part in a Periodic Deworming Program in the Peruvian Amazon

Children in the Peruvian Amazon Basin are at risk of soil-transmitted helminths (STH) infections. This study aimed to determine the prevalence of STH infection in children from a rural Amazonian community of Peru and to elucidate epidemiological risk factors associated with its perpetuation while on a school-based deworming program with mebendazole. Stool samples of children aged 2-14 years and their mothers were analyzed through direct smear analysis, Kato-Katz, spontaneous sedimentation in tube, Baermann's method, and agar plate culture. A questionnaire was administered to collect epidemiological information of interest. Among 124 children, 25.8% had one or more STH. Individual prevalence rates were as follows: Ascaris lumbricoides, 16.1%; Strongyloides stercoralis, 10.5%; hookworm, 1.6%; and Trichuris trichiura, (1.6%). The prevalence of common STH (A. lumbricoides, T. trichiura, and hookworm) was higher among children aged 2-5 years than older children (31.6% versus 12.8%; P = 0.01). In terms of sanitation deficits, walking barefoot was significantly associated with STH infection (OR = 3.28; CI 95% = 1.11-12.07). Furthermore, STH-infected children more frequently had a mother who was concomitantly infected by STH than the non-STH-infected counterpart (36.4% versus 14.1%, P = 0.02). In conclusion, STH infection is highly prevalent in children from this Amazonian community despite routine deworming. Institutional health policies may include hygiene and sanitation improvements and screening/deworming of mothers to limit the dissemination of STH. Further studies are needed to address the social and epidemiological mechanics perpetuating these infections.

Ivermectin reverses the drug resistance in cancer cells through EGFR/ERK/Akt/NF-κB pathway

Background

Discovery and development of novel drugs that are capable of overcoming drug resistance in tumor cells are urgently needed clinically. In this study, we sought to explore whether ivermectin (IVM), a macrolide antiparasitic agent, could overcome the resistance of cancer cells to the therapeutic drugs.

Methods

We used two solid tumor cell lines (HCT-8 colorectal cancer cells and MCF-7 breast cancer cells) and one hematologic tumor cell line (K562 chronic myeloid leukemia cells), which are resistant to the chemotherapeutic drugs vincristine and adriamycin respectively, and two xenograft mice models, including the solid tumor model in nude mice with the resistant HCT-8 cells and the leukemia model in NOD/SCID mice with the resistant K562 cells to investigate the reversal effect of IVM on the resistance in vitro and in vivo. MTT assay was used to investigate the effect of IVM on cancer cells growth in vitro. Flow cytometry, immunohistochemistry, and immunofluorescence were performed to investigate the reversal effect of IVM in vivo. Western blotting, qPCR, luciferase reporter assay and ChIP assay were used to detect the molecular mechanism of the reversal effect. Octet RED96 system and Co-IP were used to determine the interactions between IVM and EGFR.

Results

Our results indicated that ivermectin at its very low dose, which did not induce obvious cytotoxicity, drastically reversed the resistance of the tumor cells to the chemotherapeutic drugs both in vitro and in vivo. Mechanistically, ivermectin reversed the resistance mainly by reducing the expression of P-glycoprotein (P-gp) via inhibiting the epidermal growth factor receptor (EGFR), not by directly inhibiting P-gp activity. Ivermectin bound with the extracellular domain of EGFR, which inhibited the activation of EGFR and its downstream signaling cascade ERK/Akt/NF-κB. The inhibition of the transcriptional factor NF-κB led to the reduced P-gp transcription.

Conclusions

These findings demonstrated that ivermectin significantly enhanced the anti-cancer efficacy of chemotherapeutic drugs to tumor cells, especially in the drug-resistant cells. Thus, ivermectin, a FDA-approved antiparasitic drug, could potentially be used in combination with chemotherapeutic agents to treat cancers and in particular, the drug-resistant cancers.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1251-7) contains supplementary material, which is available to authorized users.

Occurrence, diagnosis and follow-up of canine strongyloidiosis in naturally infected shelter dogs

Strongyloidiosis by Strongyloides stercoralis is a disease of increasing interest in human and animal medicine. The scientific knowledge on canine strongyloidiosis is hindered by the poor diagnostics available. To assess the most sensitive and specific diagnostic method, feces and blood from 100 shelter dogs were screened for S. stercoralis by coprological, molecular and serological tests. Thirty-six dogs (36%) scored positive to S. stercoralis by coprology (22.3% to Baermann) and/or 30% to real time-polymerase chain reaction (rt-PCR). According to two composite reference standards (CRS) based on all coprological methods and rt-PCR (first CRS) or in combination with serology (second CRS), the most sensitive test was IFAT (93.8%; CI 82.8-98.7), followed by rt-PCR (80.6%; 95% CI 64-91.8) and Baermann (60.6%; 95% CI 42.1-77.1). The inconsistent shedding of L1 during the 4-week follow-up in infected dogs suggests the importance of multiple faecal collections for a reliable diagnosis. A combination of serological and coprological tests is recommended for the surveillance and diagnosis of S. stercoralis infection in dogs.

Tukahebwa E. Impact of a national deworming campaign on the prevalence of soil-transmitted helminthiasis in Uganda (2004-2016): Implications for national control programs

Background

Soil-transmitted Helminths and Anemia potentially reduce and retard cognitive and physical growth in school-age children with great implications for national control programs in Africa. After 13 years of deworming and limited health education campaigns, a study was undertaken to evaluate the impact of deworming interventions on the prevalence and intensity of soil-transmitted helminthic infections in school-age children in Uganda.

Methodology

A cross-sectional study was carried out in six regions of Uganda, where two districts were randomly selected per region based on the ecological zones in the country. Included in the study were the districts; Mpigi and Nakasongola from the Central; Nakapiripirit and Kotido from Karamoja; Arua and Yumbe from West Nile; Gulu and Alebtong from the North; Kaliro and Mbale from the East; Hoima and Bundibugyo in the West. Five schools were randomly selected from each district and in each school 50 children aged 6–14 years were randomly selected. Stool samples were taken each child and examined for the presence of helminthic infections. A short pretested questionnaire was administered to each participant to obtain their knowledge, attitude, and practice relating to STH infections, their control. General observations were made on environmental sanitation in the schools. The location of each school was geo-referenced using a GPS machine (Garmin^®GPSMAP62, Garmin Ltd, Southampton, UK).

Results

In total, 4,285 children were assessed including 719(16.82%) from central region, 718(16.80%) from eastern region, 719 (16.82%) from northern region, 689 (18.82%) from Karamoja region, 717(16.77%) from West Nile region and 723(16.91%) from western region. The average age of the children was 12.6 years with a standard deviation, SD 1.8 years and the minimum age was 6 years and upper age limit of 12 years. The percentage of boys (50.1%) and girls (49.9%) was comparable. 8.8% (95% CI; 8.0–9.7) were infected with at least any one STH species. Hookworm was the most prevalent (7.7%; 95% CI; 6.9–8.5) followed by whipworms (Trichuris trichiura) (1.3%; 95% CI; 1.0–1.7) and roundworms (Ascaris lumbricoides) (0.5%; 95% CI; 0.3–0.7). Some children had Schistosoma mansoni, 13.0% (95% CI; 12.0–14.0). All the children knew what soil transmitted helminths were (62.8%, 95% CI: 61.3–64.2) and most common knowledge of information were from; home (39%, 95% CI: 37.1–40.8), media (radio& newspaper)(11%, 95% CI: 9.8–12.2), school(65.7%, 95% CI: 63.9–67.5) and friends(11.5%, 95% CI: 10.3–12.7). Majority were aware of how one gets infected with soil transmitted helminths through; eating contaminated food (77.5%, 95% CI: 76.0–79.1), walking barefoot (59.6%, 95% CI: 57.8–61.5), drinking contaminated water (52.9%, 95% CI: 51.0–54.8), playing in dirty places (21.8%, 95% CI: 20.2–23.3) and dirty hands (2.3%, 95% CI: 1.7–2.9).

Conclusion

Semi-annual deworming campaigns have proved effective in significantly reducing helminthic infections in most of the districts in Uganda. Regular evaluations are vital to assess impact of the interventions and guide programme implementation. Our data shows that the prevalence of infection has been reduced to a level where STH morbidity is no longer of public health importance in most districts surveyed.

Soil-transmitted Helminths potentially reduce physical growth and retard cognitive development in school-age children (SAC) with great implications for national control programs in Africa. In Uganda, baseline investigations between 1998 and 2002, indicated STH prevalence was over 60.0% in most districts, the commonest worms infections were Hookworms, Ascaris and Trichuris. Twice a year national deworming campaign was initiated in 2003 targeting aged 1–14 years. Over ten years of deworming campaigns, has reduced the overall STH prevalence to 8.8% in 2016. The findings suggest routine deworming campaigns reduce STH exposure and infections. Periodic program evaluations are key to determining the progress made in order to achieve the elimination targets by 2020.

Mansonella perstans, Onchocerca volvulus and Strongyloides stercoralis infections in rural populations in central and southern Togo

Background

Mansonella perstans, Onchocerca volvulus and Strongyloides stercoralis are widespread helminth parasites in the tropics. Their distribution remains difficult to determine as it may change during national disease control programs and with regional mass drug administration (MDA). Epidemiological surveys are of importance to evaluate the geographical distribution of these helminth parasites and the diseases they may cause, however, up to date epidemiological evaluations on M. perstans and S. stercoralis in Togo are rare, and surveys on O. volvulus are important especially under the aspect of MDA of ivermectin which is performed since decades.

Methods

Dry blood samples (n = 924) were collected from rural populations in the Régions Central and Plateaux in Togo, and analyzed by parasite-specific real-time PCR and ELISA techniques.

Results

Dry blood samples from 733 persons where investigated by real-time PCR tested for DNA of blood-circulating M. perstans microfilaria, and a prevalence of 14.9% was detected. Distinct differences were observed between genders, positivity was higher in men increasing with age, and prevalence was highest in the Région Plateaux in Togo. IgG4 responses to O. volvulus antigen (OvAg) were studied in 924 persons and 59% were found positive. The distribution of parasite infestation between age and gender groups was higher in men increasing with age, and regional differences were detected being highest in the Région Plateaux. The diagnostic approach disclosed 64,5% positive IgG4 responses to S. stercoralis infective third-stage larvae-specific antigen (SsL3Ag) in the surveyed regions. Antigen cross reactivity of SsL3Ag with parasite co-infections may limit the calculated prevalence. Singly IgG4 positive for SsL3Ag were 13.9%, doubly positive for OvAg and SsL3Ag were 35.5% and triply positive for M. perstans, O. volvulus and S. stercoralis were 9.9%.

Conclusions

Mansonelliasis, onchocerciasis and strongyloidiasis remain prevalent in the surveyed regions, yet with local differences. Our observations suggest that transmission of M. perstans, O. volvulus and S. stercoralis may be ongoing. The degree of positive test results in the examined rural communities advocate for the continuation of MDA with ivermectin and albendazole, and further investigations should address the intensity of transmission of these parasites.

Strongyloides stercoralis and hookworm co-infection: spatial distribution and determinants in Preah Vihear Province, Cambodia

BACKGROUND

Strongyloides stercoralis and hookworm are two soil-transmitted helminths (STH) that are highly prevalent in Cambodia. Strongyloides stercoralis causes long-lasting infections and significant morbidity but is largely neglected, while hookworm causes the highest public health burden among STH. The two parasites have the same infection route, i.e. skin penetration. The extent of co-distribution, which could result in potential high co-morbidities, is unknown in highly endemic settings like Cambodia. The aim of this study was to predict the spatial distribution of S. stercoralis-hookworm co-infection risk and to investigate determinants of co-infection in Preah Vihear Province, North Cambodia.

METHODS

A cross-sectional survey was conducted in 2010 in 60 villages of Preah Vihear Province. Diagnosis was performed on two stool samples, using combined Baermann technique and Koga agar culture plate for S. stercoralis and Kato-Katz technique for hookworm. Bayesian multinomial geostatistical models were used to assess demographic, socioeconomic, and behavioural determinants of S. stercoralis-hookworm co-infection and to predict co-infection risk at non-surveyed locations.

RESULTS

Of the 2576 participants included in the study, 48.6% and 49.0% were infected with S. stercoralis and hookworm, respectively; 43.8% of the cases were co-infections. Females, preschool aged children, adults aged 19-49 years, and participants who reported regularly defecating in toilets, systematically boiling drinking water and having been treated with anthelmintic drugs had lower odds of co-infection. While S. stercoralis infection risk did not appear to be spatially structured, hookworm mono-infection and co-infection exhibited spatial correlation at about 20 km. Co-infection risk was positively associated with longer walking distances to a health centre and exhibited a small clustering tendency. The association was only partly explained by climatic variables, suggesting a role for underlying factors, such as living conditions and remoteness.

CONCLUSIONS

Both parasites were ubiquitous in the province, with co-infections accounting for almost half of all cases. The high prevalence of S. stercoralis calls for control measures. Despite several years of school-based de-worming programmes, hookworm infection levels remain high. Mebendazole efficacy, as well as coverage of and compliance to STH control programmes should be investigated.

Ivermectin susceptibility, sporontocidal effect, and inhibition of time to re-feed in the Amazonian malaria vector Anopheles darlingi

BACKGROUND

Outdoor malaria transmission hinders malaria elimination efforts in the Amazon region and novel vector control tools are needed. Ivermectin mass drug administration (MDA) to humans kills wild Anopheles, targets outdoor-feeding vectors, and can suppress malaria parasite transmission. Laboratory investigations were performed to determine ivermectin susceptibility, sporontocidal effect and inhibition of time to re-feed for the primary Amazonian malaria vector, Anopheles darlingi.

METHODS

To assess ivermectin susceptibility, various concentrations of ivermectin were mixed in human blood and fed to An. darlingi. Mosquito survival was monitored daily for 7 days and a non-linear mixed effects model with Probit analysis was used to calculate lethal concentrations of ivermectin that killed 50% (LC₅₀), 25% (LC₂₅) and 5% (LC₅) of mosquitoes. To examine ivermectin sporonticidal effect, Plasmodium vivax blood samples were collected from malaria patients and offered to mosquitoes without or with ivermectin at the LC₅₀, LC₂₅ or LC₅. To assess ivermectin inhibition of mosquito time to re-feed, concentrations of ivermectin predicted to occur after a single oral dose of 200 μg/kg ivermectin were fed to An. darlingi. Every day for 12 days thereafter, individual mosquitoes were given the opportunity to re-feed on a volunteer. Any mosquitoes that re-blood fed or died were removed from the study.

RESULTS

Ivermectin significantly reduced An. darlingi survivorship: 7-day-LC₅₀ = 43.2 ng/ml [37.5, 48.6], -LC₂₅ = 27.8 ng/ml [20.4, 32.9] and -LC₅ = 14.8 ng/ml [7.9, 20.2]. Ivermectin compound was sporontocidal to P. vivax in An. darlingi at the LC₅₀ and LC₂₅ concentrations reducing prevalence by 22.6 and 17.1%, respectively, but not at the LC₅. Oocyst intensity was not altered at any concentration. Ivermectin significantly delayed time to re-feed at the 4-h (48.7 ng/ml) and 12-h (26.9 ng/ml) concentrations but not 36-h (10.6 ng/ml) or 60-h (6.3 ng/ml).

CONCLUSIONS

Ivermectin is lethal to An. darlingi, modestly inhibits sporogony of P. vivax, and delays time to re-feed at concentrations found in humans up to 12 h post drug ingestion. The LC₅₀ value suggests that a higher than standard dose (400-μg/kg) is necessary to target An. darlingi. These results suggest that ivermectin MDA has potential in the Amazon region to aid malaria elimination efforts.

Seroepidemiological trend of strongyloidiasis in the Bolivian Chaco (1987-2013) in the absence of disease-specific control measures

OBJECTIVES

The prevalence of Strongyloides stercoralis infections is grossly underestimated because infections go mostly undetected, although they can persist for a lifetime due to the auto-infective cycle. In the Bolivian Chaco, the prevalence of soil-transmitted nematodes dropped dramatically in the past 25 years, but the mebendazole used for preventive chemotherapy has no effect on S. stercoralis. Meanwhile, the prevalence of intestinal protozoan infections remains unchanged. We compared S. stercoralis seroprevalence in rural communities of the Bolivian Chaco from 1987 to 2013.

METHODS

Sera collected during two previous serosurveys, conducted in the Chaco region in 1987 and 2013, were tested for S. stercoralis using a commercial assay (Bordier-ELISA, Bordier Affinity Products, Switzerland).

RESULTS

Overall, 355 sera were analysed, 122 from the 1987 survey and 233 from the 2013 survey. Seropositivity for S. stercoralis was significantly more prevalent in 1987 (19/122, 16% in 1987 vs. 15/233, 6% in 2013, P = 0.006), accounted for by a drop from 17% to 3% in people under 26 years of age. Multivariate analysis showed a significant association between seropositivity for S. stercoralis and age in the 2013 population (OR 1.03 for each one-year increase, 95%CI 1.00-1.05, P = 0.04), but none in 1987.

CONCLUSIONS

The significant reduction in S. stercoralis seroprevalence in Bolivian Chaco cannot be explained by preventive chemotherapy or improved social-sanitary conditions. As the drop is seen in younger generations, it is consistent with little transmission occurring. However, the risk of transmission still exists, as prevalence is persistently high in older individuals, who present a potential reservoir due to the lifelong nature of S. stercoralis infections.

Albendazole and ivermectin for the control of soil-transmitted helminths in an area with high prevalence of Strongyloides stercoralis and hookworm in northwestern Argentina: A community-based pragmatic study

BACKGROUND

Recommendations for soil-transmitted helminth (STH) control give a key role to deworming of school and pre-school age children with albendazole or mebendazole; which might be insufficient to achieve adequate control, particularly against Strongyloides stercoralis. The impact of preventive chemotherapy (PC) against STH morbidity is still incompletely understood. The aim of this study was to assess the effectiveness of a community-based program with albendazole and ivermectin in a high transmission setting for S. stercoralis and hookworm.

METHODOLOGY

Community-based pragmatic trial conducted in Tartagal, Argentina; from 2012 to 2015. Six communities (5070 people) were enrolled for community-based PC with albendazole and ivermectin. Two communities (2721 people) were re-treated for second and third rounds. STH prevalence, anemia and malnutrition were explored through consecutive surveys. Anthropometric assessment of children, stool analysis, complete blood count and NIE-ELISA serology for S. stercoralis were performed.

PRINCIPAL FINDINGS

STH infection was associated with anemia and stunting in the baseline survey that included all communities and showed a STH prevalence of 47.6% (almost exclusively hookworm and S. stercoralis). Among communities with multiple interventions, STH prevalence decreased from 62% to 23% (p<0.001) after the first PC; anemia also diminished from 52% to 12% (p<0.001). After two interventions S. stercoralis seroprevalence declined, from 51% to 14% (p<0.001) and stunting prevalence decreased, from 19% to 12% (p = 0.009).

CONCLUSIONS

Hookworm' infections are associated with anemia in the general population and nutritional impairment in children. S. stercoralis is also associated with anemia. Community-based deworming with albendazole and ivermectin is effective for the reduction of STH prevalence and morbidity in communities with high prevalence of hookworm and S. stercoralis.

Prevalence of Strongyloides stercoralis and Other Intestinal Parasite Infections in School Children in a Rural Area of Angola: A Cross-Sectional Study

Strongyloides stercoralis is widely distributed in the tropics and subtropics. The aim of this study was to determine the prevalence of S. stercoralis and other intestinal parasites and identify the risk factors for infection with S. stercoralis in a rural area of Angola. A cross-sectional study was conducted in school-age children (SAC) in Cubal, Angola. A questionnaire collecting clinical and epidemiological variables was used, and two stool samples were collected. A concentration technique (Ritchie) and a technique for detection of larvae migration (Baermann) were performed. Of 230 SAC, 56.1% were female and the mean age was 9.3 years (SD 2.45). Severe malnutrition, according to body mass index (BMI)-for-age, was observed in 20.4% of the SAC, and anemia was found in 59.6%. Strongyloides stercoralis was observed in 28 of the 230 (12.8%) SAC. Eggs of other helminths were observed in 51 (22.2%) students: Hymenolepis spp. in 27 students (11.7%), hookworm in 14 (6.1%), Schistosoma haematobium in four (1.7%), Enterobius vermicularis in four (1.7%), Ascaris lumbricoides in three (1.3%), Taenia spp. in two (0.9%), and Fasciola hepatica in one (0.4%). Protozoa were observed in 17 (7.4%) students. Detection of S. stercoralis was higher using the Baermann technique versus using formol-ether (11.3 vs. 3%). Overall prevalence of S. stercoralis in the school population of 16 studied schools in the municipal area of Cubal was greater than 10%. This fact must be considered when designing deworming mass campaigns. The use of specific tests in larvae detection is needed to avoid overlooking this parasite.

Control of chronic Strongyloides stercoralis infection in an endemic community may be possible by pharmacological means alone: Results of a three-year cohort study

Objectives

To assess the effect of treatment with ivermectin on the prevalence of S. stercoralis infection in an Australian Aboriginal population over a three year period, and to assess the validity of using a lower ELISA cut-off in diagnosis.

Methods

A three-year cohort study of 259 adult Australian Aboriginals living in a remote community in northern Australia. S stercoralis infection was diagnosed using commercial ELISA testing, and employed a lower threshold for treatment than that recommended. Follow up was conducted at 6 months and 3 years following ivermectin treatment.

Findings

Treatment with ivermectin was highly effective and resulted in a sustained fall in the prevalence of infection in the study group (Initial prevalence 35.3%, 3 year prevalence 5.8%, McNemar’s chi² = 56.5, p<0.001). Results of treatment suggested use of a lower ELISA threshold for treatment was valid in this setting. Follow up identified a small group of subjects with persistently positive ELISA serology despite repeated treatment.

Interpretation

Control of S. stercoralis infection in this cohort appears to be feasible using pharmacological treatment alone.

Infection with the worm Strongyloides stercoralis is common throughout the developing world, and in some resource poor communities living within developed societies, such as the Aboriginal communities of northern Australia. It is generally agreed that reliable diagnosis of this infection is possible by blood tests, and that the medication ivermectin represents the best available treatment, however questions remain over how to best control and eliminate the infection in areas where it is common. Strongyloides infections may be asymptomatic, and may persist indefinitely without the need for re-infection. The worm is transmitted by contact with contaminated soil. Suggested strategies for control have therefore included mass administration of ivermectin in affected areas, and environmental measures to prevent the contamination of soil. In this study we follow up a group of subjects living in an endemic community three years after they were tested and treated for strongyloides infection. We find a persisting low prevalence of infection in this group in the absence of any environmental changes or further treatment, suggesting that control of the infection in this community might be achieved through simple case finding and treatment alone. In addition, we suggest the use of a lower cut-off value for serological testing in these communities, in order to avoid missing cases of infection.

Occurrence of strongyloidiasis in privately owned and sheltered dogs: clinical presentation and treatment outcome

BACKGROUND

The increasing number of reports of human infections by Strongyloides stercoralis from a range of European countries over the last 20 years has spurred the interest of the scientific community towards this parasite and, in particular, towards the role that infections of canine hosts may play in the epidemiology of human disease. Data on the epidemiology of canine strongyloidiasis is currently limited, most likely because of the inherent limitations of current diagnostic methods.

METHODS

Faecal samples were collected directly from the rectal ampulla of 272 animals of varying age and both genders living in Apulia, southern Italy. Dogs included were either privately owned (n = 210), living in an urban area but with unrestricted outdoor access (Group 1), or shelter dogs (n = 62 out of ~400) hosted in a single shelter in the province of Bari in which a history of diarrhoea, weight loss, reduced appetite and respiratory symptoms had been reported (Group 2). Strongyloides stercoralis infection was diagnosed by coproscopy on direct faecal smear and via the Baermann method.

RESULTS

Six of 272 dogs were positive for S. stercoralis at the Baermann examination; all but one were from the shelter (Group 2) and displayed gastrointestinal clinical signs. The only owned dog (Group 1) infected with S. stercoralis, but clinically healthy, had been adopted from a shelter 1 year prior to sampling. Five infected dogs were treated with fenbendazole (Panacur®, Intervet, Animal Health, 50 mg/kg, PO daily for 5 days), or with a combination of fenbendazole and moxidectin plus imidacloprid spot-on (Im/Mox; Advocate® spot-on, Bayer). Post-treatment clearance of infection was confirmed in three dogs by Baermann examination, whereas treatment failure was documented in two dogs by Baermann and/or post-mortem detection of adult parasites.

CONCLUSIONS

This study describes, for the first time, the presence of S. stercoralis infection in sheltered dogs from southern Italy. Data indicate that S. stercoralis infection may pose a concern for sheltered animals and raise questions on potential risks of infection for staff of municipal shelters in southern European countries. Given that a single course of treatment with fenbendazole, associated or not with Im/Mox spot-on, may not eliminate the infection, effective treatment protocols should be investigated and control strategies targeting the environment considered for reducing the risk of zoonotic infection.

Side Benefits of Mass Drug Administration for Lymphatic Filariasis on Strongyloides stercoralis Prevalence on Pemba Island, Tanzania

Strongyloides stercoralis, although endemic in many countries, is not included in helminth control programs. Few data are available on the prevalence and morbidity linked to this infection. We compared data from two studies conducted in 1998 and 2013 on Pemba Island, Tanzania, involving 525 and 509 schoolchildren, respectively. In 1998, the diagnostic method used was Harada Mori, whereas in 2013 diagnosis was made by both Koga agar plate and Baermann methods. The prevalence registered was 41% in 1998 and 7% in 2013. This data suggest that the prevalence of S. stercoralis on Pemba was significantly reduced 7 years after the last ivermectin administration for preventive chemotherapy and underlines the importance and impact of large-scale preventive chemotherapy, which often goes beyond its actual target. Preventive chemotherapy with ivermectin should be recommended in areas where S. stercoralis is endemic.

Upon entering an age of global ivermectin-based integrated mass drug administration for neglected tropical diseases and malaria

Ivermectin mass drug administration (MDA) in humans to reduce malaria vectors is yet another use for this remarkable medicine whose discoverers shared the 2015 Nobel Prize in Medicine with the discoverer of artemisinin. The malaria community should join those who have long used ivermectin MDA in an integrated battle to break transmission of three vector-borne parasitic diseases.

Epidemiology of Strongyloides stercoralis in northern Italy: results of a multicentre case-control study, February 2013 to July 2014

Strongyloides stercoralis is a soil-transmitted helminth widely diffused in tropical and subtropical regions of the world. Autochthonous cases have been also diagnosed sporadically in areas of temperate climate. We aimed at defining the epidemiology of strongyloidiasis in immigrants and Italians living in three northern Italian Regions. Screening for S. stercoralis infection was done with serology, confirmation tests were a second serological method or stool agar culture. A case–control approach was adopted and patients with a peripheral eosinophil count ≥ 500/mcL were classified as cases. Of 2,701 individuals enrolled here 1,351 were cases and 1,350 controls; 86% were Italians, 48% women. Italians testing positive were in 8% (97/1,137) cases and 1% (13/1,178) controls (adjusted odds ratio (aOR) 8.2; 95% confidence interval (CI): 4.5–14.8), while positive immigrants were in 17% (36/214) cases and in 2% (3/172) controls (aOR 9.6; 95% CI: 2.9–32.4). Factors associated with a higher risk of infection for all study participants were eosinophilia (p < 0.001) and immigration (p = 0.001). Overall, strongyloidiasis was nine-times more frequent in individuals with eosinophilia than in those with normal eosinophil count.

High prevalence of Strongyloides stercoralis in school-aged children in a rural highland of north-western Ethiopia: the role of intensive diagnostic work-up

Background

Soil-transmitted helminthiases (hookworms, Ascaris lumbricoides and Trichuris trichiura) are extremely prevalent in school-aged children living in poor sanitary conditions. Recent epidemiological data suggest that Strongyloides stercoralis is highly unreported. However, accurate data are essential for conducting interventions aimed at introducing control and elimination programmes.

Methods

We conducted a cross-sectional survey of 396 randomly selected school-aged children in Amhara region in rural area in north-western Ethiopia, to assess the prevalence of S. stercoralis and other intestinal helminths. We examined stools using three techniques: conventional stool concentration; and two S. stercoralis-specific methods, i.e. the Baermann technique and polymerase chain reaction. The diagnostic accuracy of these three methods was then compared.

Results

There was an overall prevalence of helminths of 77.5%, with distribution differing according to school setting. Soil-transmitted helminths were recorded in 69.2%. Prevalence of S. stercoralis and hookworm infection was 20.7 and 54.5%, respectively, and co-infection was detected in 16.3% of cases. Schistosoma mansoni had a prevalence of 15.7%. Prevalence of S. stercoralis was shown 3.5% by the conventional method, 12.1% by the Baermann method, and 13.4% by PCR, which thus proved to be the most sensitive.

Conclusions

Our results suggest that S. stercoralis could be overlooked and neglected in Ethiopia, if studies of soil-transmitted helminths rely on conventional diagnostic techniques alone. A combination of molecular and stool microscopy techniques yields a significantly higher prevalence. In view of the fact that current control policies for triggering drug administration are based on parasite prevalence levels, a comprehensive diagnostic approach should instead be applied to ensure comprehensive control of helminth infections.

Comparison of S. stercoralis Serology Performed on Dried Blood Spots and on Conventional Serum Samples

Background: Dried blood spots (DBS) are used for epidemiological surveys on infectious diseases in settings where limited resources are available. In fact, DBS can help to overcome logistic difficulties for the collection, transport and storage of biological specimens.

Objective: To evaluate the accuracy of Strongyloides stercoralis serology performed on DBS.

Methods: A survey was proposed to children attending a school in the village of Borbon, Ecuador, and to their parents/guardians. Each participant gave consent to the collection of both serum and DBS specimens. DBS absorbed on filter papers were analyzed with a commercially available ELISA test for S. stercoralis antibodies, as well as with standard serology. The agreement between the two methods was assessed through the Cohen’s kappa coefficient.

Results: The study sample was composed of 174 children and 61 adults, for a total of 235 serum and 235 DBS samples. The serology was positive in 31/235 (13%) serum samples, and in 27/235 (11%) DBS: 4 samples resulted discordant (positive at standard serology). Cohen’s kappa coefficient was 0.921 (95% CI 0.845 – 0.998), indicating a high rate of concordance.

Conclusion: DBS are suitable for in field-surveys requiring serological testing for S. stercoralis.

Ivermectin Treatment and Sanitation Effectively Reduce Strongyloides stercoralis Infection Risk in Rural Communities in Cambodia

BACKGROUND

Strongyloides stercoralis is the only soil-transmitted helminth with the ability to replicate within its host, leading to long-lasting and potentially fatal infections. It is ubiquitous and its worldwide prevalence has recently been estimated to be at least half that of hookworm. Information on the epidemiology of S. stercoralis remains scarce and modalities for its large-scale control are yet to be determined.

METHODOLOGY/PRINCIPAL FINDINGS

A community-based two-year cohort study was conducted among the general population in a rural province in North Cambodia. At each survey, participants infected with S. stercoralis were treated with a single oral dose of ivermectin (200μg/kg BW). Diagnosis was performed using a combination of the Baermann method and Koga agar plate culture on two stool samples. The cohort included participants from eight villages who were either positive or negative for S. stercoralis at baseline. Mixed logistic regression models were employed to assess risk factors for S. stercoralis infection at baseline and re-infection at follow-up. A total of 3,096 participants were examined at baseline, revealing a S. stercoralis prevalence of 33.1%. Of these participants, 1,269 were followed-up over two years. Re-infection and infection rates among positive and negative participants at baseline were 14.4% and 9.6% at the first and 11.0% and 11.5% at the second follow-up, respectively. At follow-up, all age groups were at similar risk of acquiring an infection, while infection risk significantly decreased with increasing village sanitation coverage.

CONCLUSIONS/SIGNIFICANCE

Chemotherapy-based control of S. stercoralis is feasible and highly beneficial, particularly in combination with improved sanitation. The impact of community-based ivermectin treatment on S. stercoralis was high, with over 85% of villagers remaining negative one year after treatment. The integration of S. stercoralis into existing STH control programs should be considered without further delay.