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International Journal For Parasitology.... Apr 2024Surveillance data for Ancylostoma spp. and the A. caninum benzimidazole treatment resistance associated F167Y polymorphism using molecular diagnostics was obtained in a...
Benzimidazole F167Y polymorphism in the canine hookworm, Ancylostoma caninum: Widespread geographic, seasonal, age, and breed distribution in United States and Canada dogs.
Surveillance data for Ancylostoma spp. and the A. caninum benzimidazole treatment resistance associated F167Y polymorphism using molecular diagnostics was obtained in a large population of dogs from the United States and Canada. Real-time PCR (qPCR) for Ancylostoma spp. and allele-specific qPCR detecting a single nucleotide polymorphism (SNP) F167Y was used in 262,872 canine stool samples collected between March and December of 2022. Ancylostoma spp. was found at an overall prevalence of 2.5% (6538/262,872), with the highest prevalence in the Southern US, 4.4% (4490/103,095), and the lowest prevalence in Canada 0.6% (101/15,829). The A. caninum F167Y polymorphism was found with the highest prevalence (13.4%, n = 46/343) in the Western US and the lowest in Canada at 4.1% (4/97). The F167Y polymorphism was detected every month over the 10-month collection period. Seasonal distribution showed a peak in June for both Ancylostoma spp. (3.08%, 547/17,775) and A. caninum F167Y (12.25%, 67/547). However, the A. caninum F167Y polymorphism prevalence was highest in September (13.9%, 119/856). Age analysis indicates a higher prevalence of both hookworm infections and occurrence of resistant isolates in puppies. The breeds with the highest F167Y polymorphism prevalence in Ancylostoma spp. detected samples were poodles (28.9%), followed by Bernese Mountain dogs (25%), Cocker spaniels (23.1%), and greyhounds (22.4%). Our data set describes widespread geographic distribution of the A. caninum benzimidazole resistance associated F167Y polymorphism in the United States and Canada, with no clear seasonality compared to the Ancylostoma spp. prevalence patterns. The F167 polymorphism was present in all geographic areas with detected hookworms, including Canada. Our study highlights that the F167Y polymorphism is represented in many dog breeds, including greyhounds.
Topics: Dogs; Animals; United States; Ancylostoma; Ancylostomatoidea; Seasons; Dog Diseases; Feces; Benzimidazoles
PubMed: 38237210
DOI: 10.1016/j.ijpddr.2024.100520 -
Parasitology Mar 2024Parasitic gastrointestinal nematodes pose significant health risks to humans, livestock, and companion animals, and their control relies heavily on the use of...
Parasitic gastrointestinal nematodes pose significant health risks to humans, livestock, and companion animals, and their control relies heavily on the use of anthelmintic drugs. Overuse of these drugs has led to the emergence of resistant nematode populations. Herein, a naturally occurring isolate (referred to as BCR) of the dog hookworm, , that is resistant to 3 major classes of anthelmintics is characterized. Various drug assays were used to determine the resistance of BCR to thiabendazole, ivermectin, moxidectin and pyrantel pamoate. When compared to a drug-susceptible isolate of , BCR was shown to be significantly resistant to all 4 of the drugs tested. Multiple single nucleotide polymorphisms have been shown to impart benzimidazole resistance, including the F167Y mutation in the -tubulin isotype 1 gene, which was confirmed to be present in BCR through molecular analysis. The frequency of the resistant allele in BCR was 76.3% following its first passage in the lab, which represented an increase from approximately 50% in the founding hookworm population. A second, recently described mutation in codon 134 (Q134H) was also detected at lower frequency in the BCR population. Additionally, BCR exhibits an altered larval activation phenotype compared to the susceptible isolate, suggesting differences in the signalling pathways involved in the activation process which may be associated with resistance. Further characterization of this isolate will provide insights into the mechanisms of resistance to macrocyclic lactones and tetrahydropyrimidine anthelmintics.
Topics: Humans; Dogs; Animals; Ancylostoma; Ancylostomatoidea; Larva; Anthelmintics; Drug Resistance, Multiple; Drug Resistance
PubMed: 38163962
DOI: 10.1017/S0031182023001385 -
Journal of Visualized Experiments : JoVE Dec 2023Diagnosis of canine parasites with zoonotic potential such as Toxocara canis and Ancylostoma caninum under field conditions is usually difficult due to limited access to...
Diagnosis of canine parasites with zoonotic potential such as Toxocara canis and Ancylostoma caninum under field conditions is usually difficult due to limited access to a laboratory in rural and suburban areas in Mexico. This study aimed to detect T. canis and Ancylostoma spp. in fecal samples collected from dogs in Mexico from 2017 to 2021 under field conditions. Sample size calculation resulted in a target enrollment of 534 dogs across the country. Samples were collected directly from the rectum or the ground after defecation. Samples were stored in individual, tightly sealed, plastic bags at 4 °C. A saturated solution of sodium chloride (specific gravity [SpG] 1.20) was prepared both under field and laboratory conditions. Within 3 days of collection, 2-4 g of feces were tested for parasites using a flotation method by suspending each fecal sample in a saline solution. Feces were mixed with the flotation solution and crushed using a metal spoon. Once a uniform consistency was achieved, the fecal sample was poured into a new plastic cup using a sieve and allowed to sit for 10-15 min. Three drops from the top of the mixture were collected using a sterilized inoculating loop. The slides were placed on the microscope and parasites were identified by trained parasitologists. Fecal samples from 1,055 dogs were screened microscopically. The number of positive samples for Ancylostoma spp. was 833 (78.95% frequency) and 222 (21.04%) for T. canis. These findings illustrate the importance of identifying zoonotic helminths in dogs living in urban and rural areas in Mexico using a coproparasitoscopic technique in the laboratory and under field conditions.
Topics: Animals; Dogs; Dog Diseases; Toxocara canis; Parasites; Ancylostoma; Feces
PubMed: 38163274
DOI: 10.3791/66110 -
PLoS Pathogens Dec 2023The impact of the host immune environment on parasite transcription and fitness is currently unknown. It is widely held that hookworm infections have an immunomodulatory...
The impact of the host immune environment on parasite transcription and fitness is currently unknown. It is widely held that hookworm infections have an immunomodulatory impact on the host, but whether the converse is true remains unclear. Immunity against adult-stage hookworms is largely mediated by Type 2 immune responses driven by the transcription factor Signal Transducer and Activator of Transcription 6 (STAT6). This study investigated whether serial passage of the rodent hookworm Nippostrongylus brasiliensis in STAT6-deficient mice (STAT6 KO) caused changes in parasites over time. After adaptation to STAT6 KO hosts, N. brasiliensis increased their reproductive output, feeding capacity, energy content, and body size. Using an improved N. brasiliensis genome, we found that these physiological changes corresponded with a dramatic shift in the transcriptional landscape, including increased expression of gene pathways associated with egg production, but a decrease in genes encoding neuropeptides, proteases, SCP/TAPS proteins, and transthyretin-like proteins; the latter three categories have been repeatedly observed in hookworm excreted/secreted proteins (ESPs) implicated in immunosuppression. Although transcriptional changes started to appear in the first generation of passage in STAT6 KO hosts for both immature and mature adult stages, downregulation of the genes putatively involved in immunosuppression was only observed after multiple generations in this immunodeficient environment. When STAT6 KO-adapted N. brasiliensis were reintroduced to a naive WT host after up to 26 generations, this progressive change in host-adaptation corresponded to increased production of inflammatory cytokines by the WT host. Surprisingly, however, this single exposure of STAT6 KO-adapted N. brasiliensis to WT hosts resulted in worms that were morphologically and transcriptionally indistinguishable from WT-adapted parasites. This work uncovers remarkable plasticity in the ability of hookworms to adapt to their hosts, which may present a general feature of parasitic nematodes.
Topics: Mice; Animals; Ancylostomatoidea; Cytokines; Hookworm Infections; Nippostrongylus; STAT6 Transcription Factor
PubMed: 38079450
DOI: 10.1371/journal.ppat.1011797 -
Zoonoses and Public Health May 2024This study aimed to characterize feline hookworms from stray cats living in Bangkok.
AIMS
This study aimed to characterize feline hookworms from stray cats living in Bangkok.
METHODS AND RESULTS
A total of 56 hookworm-positive faecal samples were identified for hookworm species by using PCR targeting the ITS1, 5.8S, and ITS2 fragment and qPCR targeting ITS2. Of 56 samples, 96.4% (54/56) were identified as Ancylostoma ceylanicum and 1.8% (1/56) as Ancylostoma caninum. With qPCR, 89.3% (50/56) were identified as single A. ceylanicum infection and 5.4% (3/56) as coinfection of A. ceylanicum and A. caninum. For genetic characterization of A. ceylanicum, 10 samples were pooled, and the partial COI gene was amplified, followed by deep amplicon sequencing. Five pooled samples were analysed, and 99.73% were identified with A. ceylanicum sequences, which were allocated into 19 haplotypes (AC01-AC19). Genetic diversity findings for A. ceylanicum in Asia revealed that three of eight haplotypes considered of zoonotic significance occurred in humans, dogs, and cats, including haplotypes H01, H20, and H21. The predominant haplotype in this study, AC01, was clustered with H01-a zoonotic haplotype.
CONCLUSIONS
The diversity obtained by deep amplicon sequencing supported that the A. ceylanicum community had high genetic variation. Deep amplicon sequencing was a useful method to determine source, zoonotic potential, and host-parasite relationship.
Topics: Humans; Animals; Cats; Dogs; Ancylostoma; Zoonoses; Thailand; Ancylostomatoidea; Feces; Genetic Variation; Dog Diseases; Cat Diseases
PubMed: 38053474
DOI: 10.1111/zph.13102 -
The Lancet. Microbe Dec 2023Vaccine development against hookworm is hampered by the absence of the development of protective immunity in populations repeatedly exposed to hookworm, limiting... (Randomized Controlled Trial)
Randomized Controlled Trial
Protective efficacy of short-term infection with Necator americanus hookworm larvae in healthy volunteers in the Netherlands: a single-centre, placebo-controlled, randomised, controlled, phase 1 trial.
BACKGROUND
Vaccine development against hookworm is hampered by the absence of the development of protective immunity in populations repeatedly exposed to hookworm, limiting identification of mechanisms of protective immunity and new vaccine targets. Immunisation with attenuated larvae has proven effective in dogs and partial immunity has been achieved using an irradiated larvae model in healthy volunteers. We aimed to investigate the protective efficacy of immunisation with short-term larval infection against hookworm challenge.
METHODS
We did a single-centre, placebo-controlled, randomised, controlled, phase 1 trial at Leiden University Medical Center (Leiden, Netherlands). Healthy volunteers (aged 18-45 years) were recruited using advertisements on social media and in publicly accessible areas. Volunteers were randomly assigned (2:1) to receive three short-term infections with 50 infectious Necator americanus third-stage filariform larvae (50L3) or placebo. Infection was abrogated with a 3-day course of albendazole 400 mg, 2 weeks after each exposure. Subsequently all volunteers were challenged with two doses of 50L3 at a 2-week interval. The primary endpoint was egg load (geometric mean per g faeces) measured weekly between weeks 12 and 16 after first challenge, assessed in the per-protocol population, which included all randomly assigned volunteers with available data on egg counts at week 12-16 after challenge. This study is registered with ClinicalTrials.gov, NCT03702530.
FINDINGS
Between Nov 8 and Dec 14, 2018, 26 volunteers were screened, of whom 23 enrolled in the trial. The first immunisation was conducted on Dec 18, 2018. 23 volunteers were randomly assigned (15 to the intervention group and eight to the placebo group). Egg load after challenge was lower in the intervention group than the placebo group (geometric mean 571 eggs per g [range 372-992] vs 873 eggs per g [268-1484]); however, this difference was not statistically significant (p=0·10). Five volunteers in the intervention group developed a severe skin rash, which was associated with 40% reduction in egg counts after challenge (geometric mean 742 eggs per g [range 268-1484] vs 441 eggs per g [range 380-520] after challenge; p=0·0025) and associated with higher peak IgG1 titres.
INTERPRETATION
To our knowledge, this is the first study to describe a protective effect of short-term exposure to hookworm larvae and show an association with skin response, eosinophilic response, and IgG1. These findings could inform future hookworm vaccine development.
FUNDING
Dioraphte Foundation.
Topics: Humans; Animals; Dogs; Necator americanus; Healthy Volunteers; Netherlands; Hookworm Infections; Immunoglobulin G; Larva
PubMed: 38042152
DOI: 10.1016/S2666-5247(23)00218-5 -
Parasitology Jan 2024Hookworm infection affects millions globally, leading to chronic conditions like malnutrition and anaemia. Among the hookworm species, stands out as a generalist,...
Hookworm infection affects millions globally, leading to chronic conditions like malnutrition and anaemia. Among the hookworm species, stands out as a generalist, capable of infecting various hosts, including humans, cats, dogs and hamsters. Surprisingly, it cannot establish in mice, despite their close phylogenetic relationship to hamsters. The present study investigated the development of in immunodeficient NSG mice to determine the contribution of the immune system to host restriction. The infections became patent on day 19 post-infection (PI) and exhibited elevated egg production which lasted for at least 160 days PI. Infective larvae reared from eggs released by infected NSG mice were infectious to hamsters and capable of reproduction, indicating that the adults in the NSG mice were producing viable offspring. In contrast, showed limited development in outbred Swiss Webster mice. Furthermore, the closely related canine hookworm was unable to infect and develop in NSG mice, indicating that different mechanisms may determine host specificity even in closely related species. This is the first report of any hookworm species completing its life cycle in a mouse and implicate the immune system in determining host specificity in .
Topics: Humans; Cricetinae; Adult; Animals; Dogs; Mice; Ancylostoma; Ancylostomatoidea; Phylogeny; Hookworm Infections; Host Specificity
PubMed: 38018393
DOI: 10.1017/S0031182023001208 -
Acta Parasitologica Mar 2024Hookworms are blood-feeding nematodes that infect millions of people and animals worldwide. The most common species infecting dogs in Europe are representatives of the...
BACKGROUND
Hookworms are blood-feeding nematodes that infect millions of people and animals worldwide. The most common species infecting dogs in Europe are representatives of the family Ancylostomatidae, which differ in invasiology, biology and morphological features. However, the differentiation of invasions of species such as Uncinaria stenocephala and Ancylostoma caninum based on a coproscopic examination is problematic. For this reason, it is recommended to use molecular diagnostics for this purpose. The authors of the article investigated the prevalence of U. stenocephala in dogs kept in various living conditions in Slovakia and developed a two-step morphology-molecular analysis-based strategy to identify the genus and the species of eggs and larvae of the Ancylostomatidae family in dogs.
CONCLUSIONS
In our opinion, this work is very much needed as it shows how to effectively diagnose hookworm infestations. However, we do not agree with the information in the title of the article because such studies have already been carried out in Central Europe by other authors.
Topics: Animals; Dogs; Dog Diseases; Hookworm Infections; Ancylostomatoidea; Slovakia; Prevalence; Larva; DNA, Helminth; Feces
PubMed: 37991680
DOI: 10.1007/s11686-023-00737-3 -
Indian Journal of Medical Microbiology 2023Traditional microscopy-based methods may provide inaccurate estimates of Soil transmitted helminth (STH) infections in mild intensity of infection. Therefore, we aimed...
PURPOSE
Traditional microscopy-based methods may provide inaccurate estimates of Soil transmitted helminth (STH) infections in mild intensity of infection. Therefore, we aimed to determine the prevalence of STH infections using molecular diagnostic methods and compare the diagnostic performance of microscopy with polymerase chain reaction (PCR) in stool samples collected from pregnant women in primary care settings in Puducherry, India.
METHODOLOGY
A singleplex PCR assay was developed to detect three species of STHs, namely Ascaris lumbricoides, Necator americanus, and Ancylostoma duodenale, by targeting the internal transcribed spacer regions (ITS1 and ITS2) of 5.8S rRNA. The PCR generated 420, 662, and 515 base pairs of DNA for the respective organisms. In addition to singleplex PCR, wet and concentration microscopy techniques were used. The results were expressed as percentages with 95% confidence intervals, and the diagnostic performance of microscopy was compared with PCR in terms of sensitivity, specificity, and positive, negative predictive values and kappa statistics.
RESULTS
Among the 650 pregnant women included, 48.8% were aged 25 years or less, 59% were primigravida, and half were from rural areas. The overall prevalence of any STH infection was higher in PCR compared to microscopy (8.9% vs. 7.2%). The prevalence of Ascaris lumbricoides was higher by microscopy (5.4% vs 2.6%), while the prevalence of Necator americanus was higher by PCR (6.3%) than by microscopy (1.8%). No species of Ancylostoma duodenale was detected. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of microscopy for detecting any STH infection was 22.4%, 94.3%, 27.7%, and 92.5%, respectively. The agreement between microscopy and PCR for the identification is as follows: for any STH infection, k = 0.12, Ascaris k = 0.16, and Necator k = 0.20, respectively.
CONCLUSION
The prevalence of any STH infection identified by PCR was higher than microscopy, and the agreement between the two methods was poor.
Topics: Pregnancy; Animals; Female; Humans; Soil; Prevalence; Microscopy; Helminthiasis; Ascaris lumbricoides; Necator americanus; Polymerase Chain Reaction; Feces
PubMed: 37945120
DOI: 10.1016/j.ijmmb.2023.100427 -
Clinical and Experimental Dermatology Mar 2024Cutaneous larva migrans (CLM) results from hookworm larvae infestation, mainly Ancylostoma braziliense or Ancylostoma caninum. It is common in Sub-Saharan Africa, often...
Cutaneous larva migrans (CLM) results from hookworm larvae infestation, mainly Ancylostoma braziliense or Ancylostoma caninum. It is common in Sub-Saharan Africa, often acquired through soil contact, especially in sandy beaches, manifesting as serpiginous, erythematous and intensely pruritic tracts within the epidermis, and presenting with diverse clinical appearances. Diagnosis is mostly clinical; however, dermoscopy can enhance diagnostic accuracy and distinction from mimics. The current body of literature is deficient in its representation of dermoscopic data for CLM in Black patients. This study explores dermoscopy in nine dark-skinned patients with 16 CLM lesions. Distinctive serpiginous structureless areas displaying a range of colours, peripheral scales surrounding brown areas and brown dots were predominant features, whereas vascular characteristics were less evident. This article highlights the presence of distinct reaction patterns, including brown dots, scales, and accentuated, often disrupted brown reticular lines in addition to the characteristic winding tracts in darker skin.
Topics: Animals; Humans; Larva Migrans; Gambia; Epidermis; Ancylostoma; Black People
PubMed: 37940115
DOI: 10.1093/ced/llad381