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A comparison of helminth infections as assessed through coprological analysis and adult worm burdens in a wild host.

ABSTRACT: Coprological analysis is the most widely used diagnostic tool for helminth infection in both domestic and wild mammals. Evaluation of the efficacy of this technique is rare, due to the lack of availability of adult worm burden. Where information is available the majority of studies are in small ruminants and seldom in a wild host. This study of 289 wild badgers is the first to report the relationship between faecal egg/larval counts and adult worm burden in badgers whilst also evaluating the reliability of coprological analysis as a diagnostic tool for hookworm (Uncinaria criniformis) and lungworm (Aelurostrongylus falciformis) infection. The prevalence of hookworm and lungworm infection, as assessed through adult worm burden was 59.2% and 20.8% respectively. For both species of helminth, infection was consistently under-reported by coprological analysis compared to adult worm burden with a reported 41% sensitivity for hookworm and 10% for lungworm. A significant positive relationship was found between faecal counts and adult worm burden for both species of helminths. Additionally the density -dependent relationship often reported in helminth infection appears to be weak or non-existent in this study, up to the observed worm intensity of 500.

SUBMITTER: Byrne RL

PROVIDER: S-EPMC6261086 | biostudies-other | 2018 Dec

REPOSITORIES: biostudies-other

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A comparison of helminth infections as assessed through coprological analysis and adult worm burdens in a wild host.

Byrne Rachel L RL Fogarty Ursula U Mooney Andrew A Marples Nicola M NM Holland Celia V CV

International journal for parasitology. Parasites and wildlife 20181114 3

Coprological analysis is the most widely used diagnostic tool for helminth infection in both domestic and wild mammals. Evaluation of the efficacy of this technique is rare, due to the lack of availability of adult worm burden. Where information is available the majority of studies are in small ruminants and seldom in a wild host. This study of 289 wild badgers is the first to report the relationship between faecal egg/larval counts and adult worm burden in badgers whilst also evaluating the rel ...[more]

PMID: 30533382

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Project description:Parasitic helminths are extremely resilient in their ability to maintain chronic infection burdens despite (or maybe because of) their hosts' immune response. Explaining how parasites maintain these lifelong infections, identifying the protective immune mechanisms that regulate helminth infection burdens, and designing prophylactics and therapeutics that combat helminth infection, while preserving host health requires a far better understanding of how the immune system functions in natural habitats than we have at present. It is, therefore, necessary to complement mechanistic laboratory-based studies with studies on wild populations and their natural parasite communities. Unfortunately, the relative paucity of immunological tools for non-model species has held these types of studies back. Thankfully, recent progress in high-throughput 'omics platforms provide powerful and increasingly practical means for immunologists to move beyond traditional lab-based model organisms. Yet, assigning both metabolic and immune function to genes, transcripts, and proteins in novel species and assessing how they interact with other physiological and environmental factors requires identifying quantitative relationships between their expression and infection. Here, we used supervised machine learning to identify gene networks robustly associated with burdens of the gastrointestinal nematode Heligmosomoides polygyrus in its natural host, the wild wood mice Apodemus sylvaticus. Across 34 mice spanning two wild populations and across two different seasons, we found 17,639 transcripts that clustered in 131 weighted gene networks. These clusters robustly predicted H. polygyrus burden and included well-known effector and regulatory immune genes, but also revealed a number of genes associated with the maintenance of tissue homeostasis and hematopoiesis that have so far received little attention. We then tested the effect of experimentally reducing helminth burdens through drug treatment on those putatively protective immune factors. Despite the near elimination of H. polygyrus worms, the treatment had surprisingly little effect on gene expression. Taken together, these results suggest that hosts balance tissue homeostasis and protective immunity, resulting in relatively stable immune and, consequently, parasitological profiles. In the future, applying our approach to larger numbers of samples from additional populations will help further increase our ability to detect the immune pathways that determine chronic gastrointestinal helminth burdens in the wild.

Project description:Differences in rural and urban settings could account for distinct characteristics in the epidemiology of tuberculosis (TB). We comparatively studied epidemiological features of TB and helminth co-infections in adult patients from rural and urban settings of Tanzania.Adult patients (? 18 years) with microbiologically confirmed pulmonary TB were consecutively enrolled into two cohorts in Dar es Salaam, with ~?4.4 million inhabitants (urban), and Ifakara in the sparsely populated Kilombero District with ~?400?000 inhabitants (rural). Clinical data were obtained at recruitment. Stool and urine samples were subjected to diagnose helminthiases using Kato-Katz, Baermann, urine filtration, and circulating cathodic antigen tests. Differences between groups were assessed by ?2, Fisher's exact, and Wilcoxon rank sum tests. Logistic regression models were used to determine associations.Between August 2015 and February 2017, 668 patients were enrolled, 460 (68.9%) at the urban and 208 (31.1%) at the rural site. Median patient age was 35 years (interquartile range [IQR]: 27-41.5 years), and 454 (68%) were males. Patients from the rural setting were older (median age 37 years vs. 34 years, P?=?0.003), had a lower median body mass index (17.5 kg/m2 vs. 18.5 kg/m2, P?<? 0.001), a higher proportion of recurrent TB cases (9% vs. 1%, P?<? 0.001), and in HIV/TB co-infected patients a lower median CD4 cell counts (147 cells/?l vs. 249 cells/?l, P?=?0.02) compared to those from urban Tanzania. There was no significant difference in frequencies of HIV infection, diabetes mellitus, and haemoglobin concentration levels between the two settings. The overall prevalence of helminth co-infections was 22.9% (95% confidence interval [CI]: 20.4-27.0%). The significantly higher prevalence of helminth infections at the urban site (25.7% vs. 17.3%, P?=?0.018) was predominantly driven by Strongyloides stercoralis (17.0% vs. 4.8%, P?<? 0.001) and Schistosoma mansoni infection (4.1% vs. 16.4%, P?<? 0.001). Recurrent TB was associated with living in a rural setting (adjusted odds ratio [aOR]: 3.97, 95% CI: 1.16-13.67) and increasing age (aOR: 1.06, 95% CI: 1.02-1.10).Clinical characteristics and helminth co-infections pattern differ in TB patients in urban and rural Tanzania. The differences underline the need for setting-specific, tailored public health interventions to improve clinical management of TB and comorbidities.

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Dataset Information

A comparison of helminth infections as assessed through coprological analysis and adult worm burdens in a wild host.

Publications

A comparison of helminth infections as assessed through coprological analysis and adult worm burdens in a wild host.

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