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Trends in Parasitology Apr 2024
Topics: Animals; Raccoons; Ascaridoidea; Zoonoses; Nematode Infections
PubMed: 38151360
DOI: 10.1016/j.pt.2023.12.002 -
Avian Diseases Sep 2019is a heavily prevalent poultry parasite that thrives in the ceca of various species of gallinaceous birds. It is a small roundworm, measuring between 4 and 15 mm long,... (Review)
Review
is a heavily prevalent poultry parasite that thrives in the ceca of various species of gallinaceous birds. It is a small roundworm, measuring between 4 and 15 mm long, in the family Heterakidae. has a direct life cycle not requiring an intermediate host to complete development, and it is generally believed that poultry raised at high density on litter are at greatest risk for accumulating large numbers of the nematode. This species typically only causes mild pathology that does not significantly affect bird performance. However, is recognized as an economically important parasite by the poultry industry because its ovum serves as the vector for the protozoal parasite , the cause of histomonosis in poultry. Diagnosis of the nematode typically relies on fecal egg counts, which are prone to false negative diagnoses. Molecular tools are available for studying the nematode and diagnosing infected flocks. Treating and preventing infection is made difficult due to the low efficacy of anthelmintics for eradicating from infected birds and of disinfectants for destroying ova on contaminated farms.
Topics: Animals; Ascaridida; Ascaridida Infections; Chickens; Poultry Diseases; Turkeys
PubMed: 31967420
DOI: 10.1637/0005-2086-63.3.381 -
Journal of Helminthology Aug 2022The parasite biodiversity of mouse opossums in Brazil remains incompletely explored. We describe a new species of (Ascaridida: Subuluroidea) from the large intestine of...
The parasite biodiversity of mouse opossums in Brazil remains incompletely explored. We describe a new species of (Ascaridida: Subuluroidea) from the large intestine of the white-bellied woolly mouse opossum, , based on the results of light and scanning electron microscopy (SEM). We also partially sequenced the mitochondrial cytochrome c oxidase I (MT-CO1) gene of the new species, using molecular phylogenetic analyses to determine its relationships within the Subuluroidea superfamily. As molecular data on subuluroid species are extremely limited, few inferences could be drawn from our phylogenies. Our SEM observations showed the detailed morphology of the cephalic extremity, precloacal pseudo-sucker, caudal papillae, phasmids and vulva. sp. n. differs from the other four parasites species of marsupials by the number of caudal papillae and the structure dimensions, and size of the spicule. Moreover, sp. n. has ten pairs of caudal papillae, which is unique compared to other species. We present morphometric and molecular data on this new species, contributing to future studies on subuluroids.
Topics: Animals; Ascaridida; Brazil; Female; Mice; Opossums; Parasites; Phylogeny; Rainforest
PubMed: 35942907
DOI: 10.1017/S0022149X22000244 -
Advances in Parasitology 2020This review describes the morphology and ultrastructure of the third-stage larva of Toxocara canis, the larval stage that hatches from the egg and persists in the... (Review)
Review
This review describes the morphology and ultrastructure of the third-stage larva of Toxocara canis, the larval stage that hatches from the egg and persists in the tissues of various paratenic hosts including infected humans. This larva remains unchanged as it passes from host to host and lives for extended periods in this same body form until it makes its way to the gastro-intestinal tract of its final host. There has been less work on the anatomy and ultrastructure of the larva of Toxocara cati, but overall, it appears very similar to that of T. canis with the only apparent difference being that the larva is a few microns thinner in diameter. The paper describes the anatomy and ultrastructure of the larva and the various major structures of the various body systems including the cuticle, hypodermis, the nervous tissue, oesophagus and the lumen-free intestine, and the large excretory gland cell that fills much of the pseudocoel and which appears to be the source of the components that are recognized immunologically by the infected host. It is suggested that further detailed studies on the larva could provide significant information that would allow a greater understanding of how the larva persists within these hosts and may provide information that would make the larva an excellent link to work on nematode anatomy that would link the work being done with this model system to that of Caenorhabditis elegans and the large amount of historical work already performed on adult ascaridoid nematodes.
Topics: Animals; Humans; Larva; Toxocara; Toxocara canis
PubMed: 32381209
DOI: 10.1016/bs.apar.2020.03.002 -
Journal of Helminthology Jul 2017This review provides an inventory of the biodiversity of the anisakid species identified so far from fish and marine mammals of the NE Atlantic Ocean. The paper reviews... (Review)
Review
This review provides an inventory of the biodiversity of the anisakid species identified so far from fish and marine mammals of the NE Atlantic Ocean. The paper reviews and discusses various taxonomical and epidemiological aspects related to biodiversity assessment, with emphasis on: (1) taxa recognized as 'biological species' based on molecular/genetic markers; (2) current molecular/genetic approaches to identify the species at different developmental stages; (3) ecological data related to the actual geographical distribution and definitive host preferences of the species; (4) their distribution in various, commercially important fish species in northern European waters; (5) their possible occurrence in farmed fish; and, finally, (6) an update of their zoonotic potential as causative agents of anisakidosis in humans.
Topics: Animals; Anisakiasis; Anisakis; Aquatic Organisms; Atlantic Ocean; Biodiversity; Fishes; Mammals; Phylogeography
PubMed: 28397641
DOI: 10.1017/S0022149X1700027X -
Archives of Razi Institute Jul 2021The present study investigated the fine structure of amphids and phasmids, cuticle, muscles, and digestive tracts of Toxocara canis using optical and electron...
The present study investigated the fine structure of amphids and phasmids, cuticle, muscles, and digestive tracts of Toxocara canis using optical and electron microscopy, hematoxylin-eosin (H&E) staining, and other specific stains. A number of 38 adult T.canis worms were obtained from the animal shelter of Urmia, and their small intestines were fixated in acidified formal alcohol and 10% formalin solutions. The anterior and posterior parts of male and female T.canis worms were prepared and cut at a thickness of 4-5 μm according to the conventional method in the histological laboratory. The samples were then stained using H&E and specific periodic acid-Schiff, Masson's trichrome, and Orcein staining. The structure of amphid (anterior), phasmid (posterior), cuticle, muscles, and digestive tracts of male and female worms were studied under light microscopy. Basal, intermediate, cortex, and cuticle surface coating of the parasite were visible. Alae were also observed as the thickenings in the cuticle. The muscle layer structure consists of non-branched cylindrical cells. The intestinal tract is composed of cuticular cogs, the esophagus is of filamentous-muscular structure, and the intestine is made of columnar epithelial tissue with microvilli and glycocalyx. The amphid structure consisted of cuticular protrusions with penetrations of the cephalic framework into their inner layers. Phasmid structure also includes protrusions in the cuticle and invagination of sensory neurons. It was concluded that for the most part, the histological structure of the cuticle can be studied by optical microscopy. The muscle structure in this parasite was very similar to the skeletal muscle in mammals. Furthermore, the epithelial structure of the intestine in this parasite was largely similar to the intestinal epithelium in mammals. Finally, regarding the amphid and phasmid structures, it was observed that they were protrusions covered by cuticles where neural, filamentous, and muscular structures were the core of these protrusions.
Topics: Animals; Female; Male; Mechanoreceptors; Microscopy, Electron, Scanning; Toxocara canis
PubMed: 34223730
DOI: 10.22092/ari.2020.342252.1457 -
Veterinary Parasitology Oct 2023Parascaris spp. infect foals worldwide and foals typically shed eggs in the feces from about three to six months of age, upon which natural immunity is incurred. High...
Parascaris spp. infect foals worldwide and foals typically shed eggs in the feces from about three to six months of age, upon which natural immunity is incurred. High levels of anthelmintic resistance of Parascaris spp. are a global concern, and further understanding egg shedding patterns and fecal egg counting (FEC) data variability is of high importance. The aims of this study were to monitor Parascaris spp. egg shedding in untreated foals during 12-23 weeks of age, estimate sources of data variability, and assess precision of two ascarid FEC techniques. Fecal samples were collected weekly from 11 foals born in 2022, from May through November (29 weeks). Six subsamples were extracted from each weekly sample to determine 30 FECs between two techniques: a McMaster technique and an Automated Egg Counting System (AECS). Mixed linear modeling was carried out with age, sex, birth month, seasonality, spring- or summer-born foals, and egg counting technique as explanatory variables. Ascarid FECs were associated with age (p < 0.001), seasonality (p < 0.001), and technique (p < 0.001). The McMaster technique was more precise with a mean coefficient of variation (CV) of 34.57% and a 95% confidence interval (CI) of 30.80%- 38.30% compared to the CV for the AECS, which was 42.22% (CI: 37.70%-46.70%). Seasonality accounted for the highest proportion of variance (PV) of all covariates, but differences in PVs for covariates existed between techniques with foal age and subsample contributing more variance to the McMaster, and individual foal and seasonality contributing more to the AECS. Subsamples and replicate counts accounted for less than 1% of the total data variance. The results highlighted substantial differences in PVs between the two techniques at the subsample (AECS: 57.14%; McMaster: 77.51%) and replicate count levels (AECS: 42.86%; McMaster: 22.49%). While differences in precision were observed between the two FEC techniques, they were negligible in the data set, as the overwhelming majority of the data variability in ascarid FECs was attributed to individual foal, seasonality, and foal age.
Topics: Animals; Horses; Ascaridoidea; Horse Diseases; Ascaridida Infections; Parasite Egg Count; Ovum; Feces
PubMed: 37734131
DOI: 10.1016/j.vetpar.2023.110029 -
Diseases of Aquatic Organisms Mar 2017Despite Indonesia's high marine biodiversity, there is a lack of information regarding fish parasites in Indonesian waters. During a sampling of 136 teleost species from...
Despite Indonesia's high marine biodiversity, there is a lack of information regarding fish parasites in Indonesian waters. During a sampling of 136 teleost species from Indonesian waters, 22 of them were infected with larvae of Anisakis Dujardin, 1845, a genus with zoonotic potential. We genetically identified 118 worms, provide a revision of all available sequences of the ITS-1-5.8S-ITS-2 marker from Indonesian Anisakis in GenBank (n = 125), and establish 16 new host records. So far, 53 Indonesian teleosts harbour Anisakis spp., 32 of them with known sequence data, increasing the worldwide teleosts with genetically identified Anisakis from 155 to 177. Sequence analyses of this marker in the 243 Anisakis specimens identified 3 Anisakis sp. HC-2005 and 39 (16%) A. typica (sensu stricto). A. berlandi and A. pegreffii are reported for the first time from teleosts in the equatorial region and A. physeteris from the Pacific Ocean. The latter 3 species were exclusively found in the migratory scombrid Auxis rochei. Most common infection sites were the body cavity, with 299 (of 848) worms in the mesenteries surrounding the liver, and 129 unattached. Musculature infection was very low, demonstrating minor risk of anisakiasis for human consumers. A total of 193 worms (~79%) had a distinct genotype distinguished from A. typica by 4 positions in the ITS-1 region. This genotype is reported since 2008 as 'A. typica', 'sibling', 'Anisakis sp./type 1', 'sp. I', 'sp. 2' or 'sp. II'. To avoid further misleading identification, we hereby apply the subspecific entity Anisakis typica var. indonesiensis until description of the adults becomes available.
Topics: Animals; Anisakis; Biodiversity; DNA, Helminth; DNA, Ribosomal Spacer; Fish Diseases; Fishes; Indonesia
PubMed: 28262635
DOI: 10.3354/dao03091 -
Equine Veterinary Journal Sep 2021Strongylid and ascarid parasites are omnipresent in equine stud farms, and ever-increasing levels of anthelmintic resistance are challenging the industry with finding...
BACKGROUND
Strongylid and ascarid parasites are omnipresent in equine stud farms, and ever-increasing levels of anthelmintic resistance are challenging the industry with finding more sustainable and yet effective parasite control programs.
OBJECTIVES
To evaluate egg count levels, bodyweight and equine health under defined parasite control protocols in foals and mares at two Standardbred and two Thoroughbred stud farms.
STUDY DESIGN
Longitudinal randomised field trial.
METHODS
A total of 93 foals were enrolled and split into two treatment groups, and 99 mares were enrolled and assigned to three treatment groups. All horses underwent a health examination, and episodes of colic or diarrhoea were recorded at each faecal collection date. Bodyweights were assessed using a weight tape, and mares were body condition scored. Group A foals (FA) were dewormed at 2 and 5 months of age with a fenbendazole/ivermectin/praziquantel product, while group B foals (FB) were dewormed on a monthly basis, alternating between the above-mentioned product and an oxfendazole/pyrantel embonate product. Group A mares (MA) were dewormed twice with fenbendazole/ivermectin/praziquantel, group B mares (MB) were dewormed with the same product, when egg counts exceeded 300 strongylid eggs per gram, and group C mares (MC) were dewormed every 2 months, alternating between the two products. Health data were collected monthly for 6 months (foals) and bimonthly for 13 months (mares). Data were analysed with mixed linear models and interpreted at the α = 0.05 significance level.
RESULTS
There were no significant bodyweight differences between foal groups, but MA mares were significantly lighter than the other two groups. Very few health incidents were recorded. Foals in group FA had significantly higher ascarid and strongylid egg counts, whereas no significant differences were observed between mare groups.
MAIN LIMITATIONS
Study duration limited to one season.
CONCLUSIONS
Anthelmintic treatment intensity was lowered from the traditional intensive regimes without measurable negative health consequences for mares and foals.
Topics: Animals; Anthelmintics; Ascaridida Infections; Ascaridoidea; Feces; Female; Fenbendazole; Horse Diseases; Horses; Parasite Egg Count; Parasites
PubMed: 33119179
DOI: 10.1111/evj.13374 -
PLoS Neglected Tropical Diseases Jul 2018To gain further insight on the association between human toxocariasis and epilepsy in light of the new evidence in the last years. (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
To gain further insight on the association between human toxocariasis and epilepsy in light of the new evidence in the last years.
METHODS
A systematic review was conducted without date and language restriction in the following electronic databases: MEDLINE (PubMed), Ingenta Connect, Science Direct (Elsevier), RefDoc, Scopus, HighWire, Scielo and the database of the Institute of Neuroepidemiology and Tropical Neurology of the Limoges University (IENT). Two investigators independently conducted the search up to November 2017. A pooled odds ratio (OR) was estimated using a random effects model. Meta-regression was conducted to investigate potential sources of heterogeneity.
RESULTS
Database search produced 204 publications. Eleven case-control studies were included that were carried out in 13 countries worldwide. A total number of 4740 subjects were considered (2159 people with epilepsy and 2581 people without epilepsy). The overall pooled OR was 1.69 (95% CI 1.42-2.01) for the association between epilepsy and Toxocara spp. seropositivity. A positive association was constantly reported in the restricted analysis (WB as confirmatory or diagnostic test, younger population, and population-based studies). Meta-regression showed no statistically significant association between covariates and outcome.
CONCLUSION
The updated meta-analysis provides epidemiological evidence of a positive association between Toxocara seropositivity and epilepsy. New surveys supported the association, mainly population-based studies. On this basis, health strategies to reduce the impact of Toxocara spp are strongly advised. Further research should be performed to understand the physiopathological mechanisms of toxocara-associated epileptogenesis.
Topics: Animals; Epilepsy; Humans; Toxocara; Toxocariasis
PubMed: 30028858
DOI: 10.1371/journal.pntd.0006665