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11 result(s) for "Zendejas-Heredia, Patsy A."
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Using quantitative PCR to identify opportunities to strengthen soil-transmitted helminth control in Solomon Islands: A cross-sectional epidemiological survey
The Kato-Katz microscopy technique is the global standard for assessment of soil-transmitted helminth (STH) burden. However, major limitations include its poor sensitivity, requirement for rapid sample processing, and inability to differentiate hookworm species nor detect Strongyloides spp. infections. We assessed the prevalence and intensity of STH species in Solomon Islands by conducting a province-wide survey using quantitative PCR (qPCR) for diagnosis, which can provide much better characterisation of STH burden than microscopy. We conducted a cross-sectional survey in 18 villages in Western Province to detect infections with six STH species and quantify intensity with three. We used linear mixed model regression to identify potential water, sanitation, and hygiene (WASH) and environmental risk factors for infection. We collected stool specimens from 830 village residents. Overall STH prevalence was 63.3% (range 27.5 to 91.5% across villages), led by Necator americanus (54.5% [range 17.5-89.4%]), followed by Ancylostoma ceylanicum (15.5% [range 2.8-45.8%]), Trichuris trichiura (9.1% [range 0-79.2%]), and Strongyloides spp. (3.2% [range 0-29.2%]). Most infections were of light intensity for N. americanus (85.7%) and T. trichiura (90.7%). Owning a household latrine was associated with a lower risk of N. americanus infection (AOR 0.41, 95% CI 0.24-0.68) while greater precipitation was linked to more common T. trichiura infection (AOR 1.14, 95% CI 1.04-1.25). In this first large-scale population survey of STH in the Pacific using qPCR, we found evidence that ivermectin should be incorporated into STH control programmes because of the presence of T. trichiura and Strongyloides spp., both of which are poorly responsive to albendazole. Furthermore, One Health strategies are needed for improved A. ceylanicum and Strongyloides spp. control, WASH access and use should be improved to complement deworming programmes, and control efforts should ideally be expanded to entire communities. ClinicalTrials.gov Australian and New Zealand Clinical Trials Registry ACTRN12618001086257.
Comparison of the egg recovery rates and limit of detection for soil-transmitted helminths using the Kato-Katz thick smear, faecal flotation and quantitative real-time PCR in human stool
Background Monitoring the success of soil-transmitted helminth (STH) control programs relies on accurate diagnosis and quantitative assessment of infection prevalence and intensity. As preventative chemotherapeutic program coverage for STH expands, the necessity of gaining insights into the relative or comparative sensitivities, in terms of limits of detection (LOD) and egg-recovery-rates (ERR) for microscopy and quantitative polymerase chain reaction qPCR-based diagnostic techniques becomes imperative to inform suitability for their intended use for large scale STH monitoring and treatment efficacy studies. Methodology/Principal findings The diagnostic performance in terms of ERR and LOD of the Kato-Katz (KK) thick smear technique, sodium nitrate (NaNO.sub.3) faecal floatation (FF) and qPCR for the accurate detection and enumeration of STH eggs were calculated and expressed in eggs per gram (EPG), by experimentally seeding parasite-free human faeces with Ascaris spp., Trichuris spp. and Necator americanus eggs representing low, medium and high intensity infections. The efficiency of NaNO.sub.3 flotation was also calculated over a range of specific gravities (SpGr) for the optimum recovery of STH eggs. FF of SpGr 1.30 recovered 62.7%, 11% and 8.7% more Trichuris spp., Necator americanus and Ascaris spp. eggs respectively, than the recommended SpGr of 1.20. All diagnostic methods demonstrated strong direct correlation to the intensity of seeded EPG. KK and FF (SpGr 1.30) resulted in significant lower ERRs compared to qPCR (p <0.05). qPCR demonstrated significantly (p <0.05) greater sensitivity with an ability to detect as little as 5 EPG for all three STH, compared to 50 EPG by KK and FF (SpGr 1.30). Conclusions/Significance This study compares the diagnostic parameters in terms of LOD and ERRs of STHs for the KK, FF and qPCR. These results indicate that the diagnostic performance of qPCR assays should be considered by control programs in the phase that aims to seek confirmation of transmission break and cessation of preventive chemotherapy in low-transmission settings, in line with the control targets of the WHO neglected tropical diseases 2030 Roadmap.
Zoonotic Ancylostoma ceylanicum Infection in Coyotes from Guanacaste Conservation Area, Costa Rica, 2021
Ancylostoma ceylanicum is the second most common hookworm infecting humans in the Asia-Pacific region. Recent reports suggest presence of the parasite in the Americas. We report A. ceylanicum infections in coyotes from the Guanacaste Conservation Area, Costa Rica. Our findings call for active surveillance in humans and animals.
A systematic review and meta-analysis of human and zoonotic dog soil-transmitted helminth infections in Australian Indigenous communities
Soil-transmitted helminths (STH) infect 1.5 billion people and countless animals worldwide. In Australian Indigenous communities, STH infections have largely remained endemic despite control efforts, suggesting reservoirs of infection may exist. Dogs fulfil various important cultural, social and occupational roles in Australian Indigenous communities and are populous in these settings. Dogs may also harbour zoonotic STHs capable of producing morbidity and mortality in dogs and humans. This review provides an overview of human and zoonotic STH infections, identifies the Australian Indigenous locations affected and the parasite species and hosts involved. The meta-analysis provides estimates of individual study and pooled true prevalence of STH infections in Australian Indigenous communities and identifies knowledge gaps for further research on zoonotic or anthroponotic potential. A systematic literature search identified 45 eligible studies documenting the presence of Strongyloides stercoralis , Trichuris trichiura , Ancylostoma caninum , Ancylostoma duodenale , Ancylostoma ceylanicum , undifferentiated hookworm, and Ascaris lumbricoides . Of these studies, 26 were also eligible for inclusion in meta-analysis to establish true prevalence in the light of imperfect diagnostic test sensitivity and specificity by Rogan-Gladen and Bayesian methods. These studies revealed pooled true prevalence estimates of 18.9% (95% CI 15.8–22.1) for human and canine S . stercoralis infections and 77.3% (95% CI 63.7–91.0) for canine A . caninum infections indicating continued endemicity, but considerably more heterogenous pooled estimates for canine A . ceylanicum infections, and A . duodenale , undifferentiated hookworm and T . trichiura in humans. This review suggests that the prevalence of STHs in Australian Indigenous communities has likely been underestimated, principally based on imperfect diagnostic tests. Potential misclassification of hookworm species in humans and dogs due to outdated methodology, also obscures this picture. High-quality contemporary studies are required to establish current true prevalence of parasite species in all relevant hosts to guide future policy development and control decisions under a culturally sound One Health framework.
Effect of experimental hookworm infection on insulin resistance in people at risk of type 2 diabetes
The reduced prevalence of insulin resistance and type 2 diabetes in countries with endemic parasitic worm infections suggests a protective role for worms against metabolic disorders, however clinical evidence has been non-existent. This 2-year randomised, double-blinded clinical trial in Australia of hookworm infection in 40 male and female adults at risk of type 2 diabetes assessed the safety and potential metabolic benefits of treatment with either 20 ( n  = 14) or 40 ( n  = 13) Necator americanus larvae (L3) or Placebo ( n  = 13) (Registration ACTRN12617000818336). Primary outcome was safety defined by adverse events and completion rate. Homoeostatic model assessment of insulin resistance, fasting blood glucose and body mass were key secondary outcomes. Adverse events were more frequent in hookworm-treated participants, where 44% experienced expected gastrointestinal symptoms, but completion rates were comparable to Placebo. Fasting glucose and insulin resistance were lowered in both hookworm-treated groups at 1 year, and body mass was reduced after L3-20 treatment at 2 years. This study suggests hookworm infection is safe in people at risk of type 2 diabetes and associated with improved insulin resistance, warranting further exploration of the benefits of hookworms on metabolic health. A beneficial effect of parasitic worms on metabolic health has been postulated based on epidemiological and animal studies. Here, the authors show in a phase I clinical trial that treatment of people at risk of type 2 diabetes with hookworms is safe and may improve key measures of metabolic health.
Zoonotic Soil-Transmitted Helminths in Free-Roaming Dogs, Kiribati
Soil-transmitted helminths are highly prevalent in the Asia-Pacific region. We report a 96.5% prevalence of zoonotic soil-transmitted helminths in dogs in Kiribati. We advocate for urgent implementation of treatment and prevention programs for these zoonotic pathogens, in line with the Kiribati-World Health Organization Cooperation Strategy 2018-2022.
Ancylostoma ceylanicum Hookworms in Dogs, Grenada, West Indies
Ancylostoma ceylanicum hookworms are recognized agents of human infection in the Asia-Pacific region. We investigated prevalence of zoonotic hookworm infections in dogs in Grenada in 2021; 40.8% were infected by hookworms, including Ancylostoma ceylanicum. Surveillance of this parasite in dogs and humans is needed in tropical/subtropical countries in the Americas.
Zoonotic helminths of dogs and risk factors associated with polyparasitism in Grenada, West Indies
Canine soil-transmitted helminths (STHs) cause important zoonoses in the tropics, with varying degrees of intensity of infection in humans and dogs. This study aimed to investigate the prevalence and associated risk factors for STHs in community dogs residing in Grenada, West Indies. In May 2021, 232 canine fecal samples were examined for zoonotic helminths by microscopy (following flotation), and genomic DNA from a subset of 211 of these samples were subjected to multiplex qPCR for the detection and specific identification of hookworms, Toxocara spp. and Strongyloides. Microscopic examination revealed that 46.5% (108/232, 95% CI 40–52.9), 9% (21/232, 95% CI 5.35–12.7) and 5.2% (12/232, 95% CI 2.3–8) of the samples contained eggs of Ancylostoma spp., Toxocara spp. and Trichuris vulpis, respectively. Multiplex qPCR revealed that, 42.2% (89/211, 95% CI 35.5–48.8) were positive for at least 1 zoonotic parasite. Of these, 40.8% (86/211, 95% CI 34.1–47.3) of samples tested positive for Ancylostoma spp., 36% (76/211, 95% CI 29.5–42.9) were positive for A. caninum, 13.3% (28/211, 95% CI 9–18.6) for A. ceylanicum, 5.7% for T. canis (12/211, 95% CI 2.97–8.81) and 1% (2/211, 95% CI 0–2.26) for Strongyloides spp. (identified as S. stercoralis and S. papillosus by conventional PCR-based Sanger sequencing). Using a multiple logistic regression model, a low body score and free-roaming behaviour were significant predictors of test-positivity for these parasitic nematodes in dogs (P < 0.05). Further studies of zoonotic STHs in humans should help elucidate the public health relevance of these parasites in Grenada.
Imported zoonotic Ancylostoma ceylanicum and Ancylostoma braziliense infections in a cat in Romania
Hookworms are widespread zoonotic parasites affecting humans and companion animals worldwide. We report molecular characterization of Ancylostoma ceylanicum and A. braziliense in a cat imported into Romania from Guadeloupe, an overseas administrative region of the French Republic in the Caribbean. This finding underscores the role of molecular diagnostics in detecting the transboundary introduction of exotic hookworms with significant zoonotic potential. Graphical Abstract
An Integrated Coproscopic and Molecular Method Provides Insights into the Epidemiology of Zoonotic Intestinal Helminths of Dogs across Cambodia
Introduction. In Cambodia, a limited number of focal surveys targeting dogs in rural communities have reported intestinal helminths of potential zoonotic risk as highly endemic. In this study, we investigated the prevalence, diversity, distribution, and risk predictors associated with zoonotic intestinal helminths infecting pet, community, and pagoda dogs across rural and urban settings in Cambodia through an integrated coproscopic and molecular approach. Methods. Faecal samples, demographic, and clinical data were collected from 457 dogs across Cambodia. Faeces were screened for gastroenteric parasites using sodium nitrate faecal floatation (1.30 SpGr) and multiplex TaqMan-based quantitative polymerase chain reaction (qPCR) assays for differentiation of canine hookworm species (Ancylostoma ceylanicum, Ancylostoma braziliense, Ancylostoma caninum, and Uncinaria stenocephala) and for Strongyloides spp. Conventional polymerase chain reaction (PCR) and DNA sequencing was used to further characterise eggs resembling zoonotic helminths that could not be designated to a species level by light microscopy alone. In addition, infection intensities for hookworms and Toxocara as eggs per gram of faeces were estimated to assess the dog age-dependent contribution of these zoonotic parasites in the environment. Finally, multiple logistic regression analyses were performed to identify risk predictors for gastrointestinal parasitoses. Results. Using combined coproscopic and molecular methods, we detected at least one helminth in 79% of the sampled dogs. Of these, 78.8% were infected with at least one zoonotic species, with A. ceylanicum (50%) and A. caninum (50%) constituting the most common parasites followed by A. braziliense (20%), Toxocara canis (15%), Strongyloides spp. (5%), Dipylidium caninum (2%), and Eucoleus spp. (2%). The indirect zoonotic helminths Spirometra erinaceieuropaei, Spirometra mansoni, and Haplorchis yokogawai contributed to 14% of the total infections in dogs. Dogs were also found mechanically passing eggs of large trematodes such as Fischoederius elongatus, Schistosoma spp., Paramphistomatidae, and Gastrothylax crumenifer. Contradictory to previous reports, the prevalence of T. canis was highest in adult dogs with egg shedding intensity peaking in dogs more than 7 years of age. Finally, we found that pale mucous membranes and low total protein were predictors of hookworm infection in dogs (p<0.05). Conclusion. Dogs within both rural and urban settings across Cambodia are highly infected with a large diversity of zoonotic gastroenteric helminths. This study reports the presence of A. braziliense, the aetiological agent of hookworm-related “creeping eruptions” for the first time in Cambodia. Moreover, infection intensity data suggest that adult dogs should also be targeted by deworming campaigns to reduce the prevalence of zoonotic hookworm and T. canis infections within the country. These results highlight the need for an integrated approach to canine population management and parasite control in dogs across urban and rural settings in Cambodia to mitigate the public health risks and impacts posed by these helminths.