-
PLoS Neglected Tropical Diseases Oct 2022Soil-transmitted helminths (STH) infect 1.5 billion people and countless animals worldwide. In Australian Indigenous communities, STH infections have largely remained... (Meta-Analysis)
Meta-Analysis
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 Potential misclassification of hookworm species in humans and dogs due to outdated methodology, also obscures this picture.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.
Topics: Humans; Dogs; Animals; Soil; Bayes Theorem; Australia; Helminths; Ascaris lumbricoides; Trichuris; Helminthiasis; Hookworm Infections; Ancylostomatoidea; Ancylostoma; Zoonoses; Prevalence; Feces
PubMed: 36279298
DOI: 10.1371/journal.pntd.0010895 -
Parasites & Vectors May 2023Few anthelminthics are currently available, manifesting the urgent need for new treatment options. In vitro profiling of current anthelminthics against larval and adult...
BACKGROUND
Few anthelminthics are currently available, manifesting the urgent need for new treatment options. In vitro profiling of current anthelminthics against larval and adult stage helminths displayed varying effects on closely related worm species and between life stages of the same species. Conversely, limited research has been performed on the egg stage of human hookworms, and the effects of investigational compounds on the egg stage are not routinely assessed.
METHODS
We profiled the development and hatching of Heligmosomoides polygyrus, Ancylostoma duodenale and Necator americanus eggs isolated from rodent faeces in liquid media with various nutrient levels, osmolar concentrations, and acidities in dependence on incubation temperature and light exposure. Incubation conditions were optimised to allow the study of drug effect on immature and embryonated eggs. We analysed concentration-effect relationships of commercially available anthelminthics over 72 h.
RESULTS
Rapid embryonation and hatching were observed at room temperature with and without light exposure without nutrient supplementation in a wide range of acidities. Hookworms hatched optimally at room temperature in PBS achieving > 75% hatching over 34 h. Developmental delays were seen when eggs were stored at 4 °C with no effect on viability. Similar delays were also seen with increased osmolar concentrations resulting in decreased viability. Benzimidazole anthelminthics effectively reduced the viability and prevented hatching of hookworm eggs, with albendazole and thiabendazole eliciting particularly potent effects at EC values below 1 µM. Macrolide anthelminthics as well as emodepside, oxantel pamoate, and pyrantel pamoate were inactive while monepantel, levamisole, and tribendimidine displayed varied potencies among the hookworm species.
CONCLUSION
The presented egg-hatching assay will complement ongoing anthelminthic drug discovery and allow a full characterisation of drug activity against all life stages. In the development and application of the egg-hatching assay, good accordance was observed between the three hookworm species evaluated. Marketed anthelminthics show differences of drug action compared to larval and adult stages highlighting the importance of profiling drug activity against all life stages.
Topics: Animals; Adult; Humans; Anthelmintics; Hookworm Infections; Ancylostomatoidea; Albendazole; Necator americanus; Ancylostoma; Larva
PubMed: 37143169
DOI: 10.1186/s13071-023-05771-8 -
PLoS Neglected Tropical Diseases Sep 2022Limited understanding exists about the interactions between malaria and soil-transmitted helminths (STH), their potential geographical overlap and the factors driving...
BACKGROUND
Limited understanding exists about the interactions between malaria and soil-transmitted helminths (STH), their potential geographical overlap and the factors driving it. This study characterised the geographical and co-clustered distribution patterns of malaria and STH infections among vulnerable populations in sub-Saharan Africa (SSA).
METHODOLOGY/PRINCIPAL FINDINGS
We obtained continuous estimates of malaria prevalence from the Malaria Atlas Project (MAP) and STH prevalence surveys from the WHO-driven Expanded Special Project for the Elimination of NTDs (ESPEN) from Jan 1, 2000, to Dec 31, 2018. Although, MAP provides datasets on the estimated prevalence of Plasmodium falciparum at 5km x 5km fine-scale resolution, we calculated the population-weighted prevalence of malaria for each implementation unit to ensure that both malaria and STH datasets were on the same spatial resolution. We incorporated survey data from 5,935 implementation units for STH prevalence and conducted the prevalence point estimates before and after 2003. We used the bivariate local indicator of spatial association (LISA analysis) to explore potential co-clustering of both diseases at the implementation unit levels among children aged 2-10 years for P. falciparum and 5-14 years for STH, living in SSA. Our analysis shows that prior to 2003, a greater number of SSA countries had a high prevalence of co-endemicity with P.falciparium and any STH species than during the period from 2003-2018. Similar prevalence and distribution patterns were observed for the co-endemicity involving P.falciparum-hookworm, P.falciparum-Ascaris lumbricoides and P.falciparum-Trichuris trichiura, before and after 2003. We also observed spatial variations in the estimates of the prevalence of P. falciparum-STH co-endemicity and identified hotspots across many countries in SSA with inter-and intra-country variations. High P. falciparum and high hookworm co-endemicity was more prevalent in West and Central Africa, whereas high P. falciparum with high A. lumbricoides and high P. falciparum with high T. trichiura co-endemicity were more predominant in Central Africa, compared to other sub-regions in SSA.
CONCLUSIONS/SIGNIFICANCE
Wide spatial heterogeneity exists in the prevalence of malaria and STH co-endemicity within the regions and within countries in SSA. The geographical overlap and spatial co-existence of malaria and STH could be exploited to achieve effective control and elimination agendas through the integration of the vertical control programmes designed for malaria and STH into a more comprehensive and sustainable community-based paradigm.
Topics: Africa South of the Sahara; Ancylostomatoidea; Animals; Child; Feces; Helminthiasis; Helminths; Humans; Malaria; Malaria, Falciparum; Prevalence; Soil
PubMed: 36178964
DOI: 10.1371/journal.pntd.0010321 -
The Korean Journal of Parasitology Sep 2006Soil-transmitted helminths (STH), namely Ascaris, Trichuris and hookworms (Ancylostoma and Necator), present a global health problem to about a half of the earthos... (Review)
Review
Soil-transmitted helminths (STH), namely Ascaris, Trichuris and hookworms (Ancylostoma and Necator), present a global health problem to about a half of the earthos population. In the Republic of Korea, STH were highly prevalent and were considered a high priority target for national control. To promote the control, a non-governmental organization named Korea Association for Parasite Eradication (currently Korea Association of Health Promotion) was founded in 1964, and mass fecal examination followed by selective mass chemotherapy with anthelmintics was performed twice a year from 1969 to 1995 targeting whole nationwide schoolchildren. Meanwhile, decreasing patterns of national STH infections have been monitored by 7 timeso quinquennial national surveys targeting general population. In 1971, the overall intestinal helminth egg positive rate was 84.3% (Ascaris 58.2%, Trichuris 65.4%, and hookworms 10.7%), which became 63.2% in 1976, 41.1% in 1981, 12.9% in 1986, 3.8% in 1992, 2.4% in 1997, and 4.3% (Ascaris 0.03%, Trichuris 0.02%, and hookworms 0%) in 2004. During the control period, national economy rapidly developed, and living standards including environment, sanitation, and agricultural technology greatly improved, which undoubtedly boosted the STH control effects. Our experience indicates that social driving force to establish an eligible national control system to conduct repeated mass chemotherapy, together with improvement of environment and sanitation, is important for initiating and achieving STH control in a developing community.
Topics: Ancylostomatoidea; Animals; Antinematodal Agents; Ascaris lumbricoides; Humans; Korea; Nematoda; Nematode Infections; Soil; Trichuris
PubMed: 16969055
DOI: 10.3347/kjp.2006.44.3.177 -
International Journal For Parasitology.... Aug 2023Ancylostoma caninum is the most common and important gastrointestinal nematode of dogs in the United States. Despite recent reports of A. caninum isolates resistant to...
Ancylostoma caninum is the most common and important gastrointestinal nematode of dogs in the United States. Despite recent reports of A. caninum isolates resistant to all classes of anthelmintics, little is known about the frequency and extent of this anthelmintic resistance. The study aim was to evaluate the efficacy of three commercial anthelmintic products in the treatment of foxhound dogs with a history of persistent A. caninum infections. In the first phase of this study, 35 foxhounds were randomly divided into three treatment groups: moxidectin/imidacloprid (MI), pyrantel pamoate/febantel/praziquantel (PFP), and emodepside/praziquantel (EP). Fecal samples were collected on day 0, 11, and 33 post-treatment (PT), and hookworm eggs were quantified using the mini-FLOTAC technique with a multiplication factor of 5 eggs per gram (EPG). The fecal egg count reduction (FECR) on day 11 PT was 65% (95% CI: 62%-68%) for MI, 69% (95% CI: 66%-72%) for PFP, and 96% (95% CI: 94%-97%) for EP. On day 33 PT, the FEC in the MI and PFP groups returned to almost the same values as on day 0, while in the EP group, the FEC remained low. Since MI and PFP proved ineffective, 32 animals were randomly divided into two groups in the second phase. They were treated either with a combination of MI/PFP or EP. The FECR at day 13 PT for the combination MI/PFP was 89% (95% CI: 87%-91%) and 99% (95% CI: 98%-99%) for EP. These results suggest that this A. caninum population is resistant to multiple anthelmintics. Although the combination of MI/PFP improved the anthelmintic efficacy, the FECR remained below 90%. Future studies are indicated to evaluate further the epidemiology of persistent hookworm infections in dogs in the US and to identify more effective treatment protocols as they pose a significant health risk to canine and human health.
Topics: Animals; Dogs; Ancylostoma; Ancylostomatoidea; Anthelmintics; Dog Diseases; Feces; Hookworm Infections; Nematoda; Parasite Egg Count; Praziquantel
PubMed: 37481894
DOI: 10.1016/j.ijpddr.2023.07.001 -
The Cochrane Database of Systematic... Apr 2012Allergic rhinitis is a disorder of the nasal membranes and surrounding tissues, and a worldwide cause of illness and disability. Helminths are complex tissue-dwelling or... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Allergic rhinitis is a disorder of the nasal membranes and surrounding tissues, and a worldwide cause of illness and disability. Helminths are complex tissue-dwelling or lumen-dwelling organisms that inhabit larger organisms and are frequently asymptomatic. Helminths modulate the natural immune responses of their human hosts, and may prevent or cure immune-mediated or allergic diseases (e.g. allergic rhinitis) in the host. Non-randomised studies support this hypothesis.
OBJECTIVES
To assess the safety and effectiveness of helminth therapy in people with allergic rhinitis.
SEARCH METHODS
We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; ICTRP and additional sources for published and unpublished trials. The date of the search was 24 June 2011.
SELECTION CRITERIA
All randomised controlled trials where the intervention was any helminth species or combination of helminth species, administered to people with allergic rhinitis in any dose, by any route and for any duration of exposure. We accepted both intermittent and persistent allergic rhinitis patients.
DATA COLLECTION AND ANALYSIS
We independently extracted data and assessed eligibility and risk of bias using a standardised data collection form. We resolved any disagreement through discussion. We combined dichotomous data using risk ratio (RR) and continuous data using mean difference (MD), presenting both with 95% confidence intervals (CI).
MAIN RESULTS
We found five reports of two single-centre, placebo-controlled, double-blinded studies (130 participants). Participants in both studies were a mix of adults with either intermittent or persistent allergic rhinitis. Both studies had a low risk of bias. One study, with 12 weeks' follow-up, used a single percutaneous application of 10 Necator americanus (i.e. human hookworm) larvae. The other study, with 24 weeks' follow-up, used three-weekly oral dosing with 2500 Trichuris suis (i.e. pig whipworm) eggs in aqueous suspension. Of 17 outcomes evaluated in this review, eight were positive (i.e. favoured helminths). Participants taking helminths had no reduction in allergic rhinitis symptoms, percentage of well days (i.e. days with minimal symptoms and no use of medication for allergic rhinitis), lung function measures and quality of life scores. Total use of medication for allergic rhinitis (eye drops, nasal sprays, tablets) did not change; however, in the helminth group there was a statistically significant reduction in the percentage of days during the grass pollen season when participants needed to take tablets as rescue medication for their allergic rhinitis symptoms (MD -14.0%, 95% CI -26.6 to -1.40); in a typical 60-day pollen season this 14% reduction translates into 19 days when tablets would be needed in the helminth group versus 27 days when tablets would be needed in the placebo group. Participants taking helminths percutaneously (i.e. as hookworm larvae) had local skin itching and redness in the first few days after administration. Participants taking helminths were more likely to report any gastrointestinal adverse event (RR 1.79, 95% CI 1.31 to 2.45), moderate or severe abdominal pain (RR 7.67, 95% CI 1.87 to 31.57), moderate or severe flatulence (RR 2.01, 95% CI 1.06 to 3.81) and moderate or severe diarrhoea (RR 1.99, 95% CI 1.18 to 3.37). There was no difference between the helminth and placebo groups in the incidence of serious adverse events, and in study withdrawals.
AUTHORS' CONCLUSIONS
There is currently insufficient evidence on the efficacy, tolerability and likely costs of helminth therapy to support its use in the routine management of allergic rhinitis. Administered to humans in carefully measured doses, helminths appear to be safe. More preclinical studies should be performed, before larger and extended duration trials of helminths for allergic rhinitis are carried out. Future studies should collect and report comparative data on the costs of helminth therapy versus conventional pharmacotherapy.
Topics: Adult; Ancylostomatoidea; Animals; Helminths; Humans; Immunotherapy; Randomized Controlled Trials as Topic; Rhinitis, Allergic, Perennial; Rhinitis, Allergic, Seasonal; Trichuris
PubMed: 22513973
DOI: 10.1002/14651858.CD009238.pub2 -
Malaria Journal Sep 2011In the past decade there have been an increasing number of studies on co-infections between worms and malaria. However, this increased interest has yielded results that... (Review)
Review
In the past decade there have been an increasing number of studies on co-infections between worms and malaria. However, this increased interest has yielded results that have been at times conflicting and made it difficult to clearly grasp the outcome of this interaction. Despite the heterogeneity of study designs, reviewing the growing body of research may be synthesized into some broad trends: Ascaris emerges mostly as protective from malaria and its severe manifestations, whereas hookworm seems to increase malaria incidence. As efforts are made to de-worm populations in malaria endemic areas, there is still no clear picture of the impact these programmes have in terms of quantitative and qualitative changes in malaria.
Topics: Ancylostomatoidea; Animals; Ascariasis; Ascaris; Comorbidity; Hookworm Infections; Humans; Incidence; Malaria
PubMed: 21910854
DOI: 10.1186/1475-2875-10-259 -
Journal of Travel Medicine 2007
Review
Topics: Albendazole; Ancylostomatoidea; Animals; Anthelmintics; Diagnosis, Differential; Hookworm Infections; Humans; Larva Migrans; Travel; Tropical Climate
PubMed: 17883464
DOI: 10.1111/j.1708-8305.2007.00148.x -
Scientific Reports Apr 2022The dual effects of co-infection of Plasmodium spp. and hookworm on malaria remain under debate. This study investigated prevalence, prevalence odds ratio (POR) of... (Meta-Analysis)
Meta-Analysis
The dual effects of co-infection of Plasmodium spp. and hookworm on malaria remain under debate. This study investigated prevalence, prevalence odds ratio (POR) of co-infection and impact of co-infection on malaria parasite density and haemoglobin levels in comparison to Plasmodium mono-infection. The protocol for this systematic review and meta-analysis is registered at PROPERO under ID: CRD42020202156. Relevant literatures were obtained from PubMed, ISI Web of Science, and Scopus on 25 December 2020. Mean difference (MD) and confidence interval (CI) of malaria parasite density and haemoglobin were compared using a random effect model. Heterogeneity was assessed using Cochrane Q and I statistics. Publication bias was determined by visualising funnel plot asymmetry. Of 1756 articles examined, 22,191 malaria cases across 37 studies included 6096 cases of co-infection of Plasmodium spp. and hookworm. The pooled prevalence was 20% (95% CI 15-26%, I 99.6%, 37 studies) and was varied in terms of geographical region. Co-infection occurred by chance (OR 0.97, p 0.97, 95% CI 0.73-1.27, I 95%, 30 studies). The mean malaria parasite density for co-infection (478 cases) was similar to Plasmodium mono-infection (920 cases) (p 0.24, MD 0.86, 95% CI - 0.58-2.29, I 100%, 7 studies). The mean haemoglobin level for co-infection (90 cases) was similar to Plasmodium mono-infection (415 cases) (p 0.15, MD - 0.63, 95% CI - 1.49-0.23, I 98%, 4 studies). Co-infection was common and occurred by chance but varied by geographic region. Further studies are required to investigate the mechanism of hookworm infection on malaria severity. Additionally, detection of hookworm infections among patients with malaria in endemic areas of both diseases is recommended to prevent severe malaria.
Topics: Ancylostomatoidea; Animals; Coinfection; Hookworm Infections; Humans; Malaria; Parasites; Plasmodium; Prevalence
PubMed: 35477943
DOI: 10.1038/s41598-022-10569-2 -
Parasite Immunology Jun 2022In Hookworm infection, neutrophils have long had the image of the villain, being recruited to the site of larval migration because of damage but participating themselves... (Review)
Review
In Hookworm infection, neutrophils have long had the image of the villain, being recruited to the site of larval migration because of damage but participating themselves in tissue injury. With recent developments in neutrophil biology, there is an increasing body of evidence for the role of neutrophils as effector cells in hookworm immunity. In particular, their ability to release extracellular traps, or neutrophil extracellular traps (NETs), confer neutrophils a larvicidal activity. Here, we review recent evidence in this nascent field and discuss the avenue for future research on NETs/hookworm interactions.
Topics: Ancylostomatoidea; Animals; Extracellular Traps; Hookworm Infections; Neutrophils
PubMed: 35124825
DOI: 10.1111/pim.12911