scholarly journals Helminth eggs from early cretaceous faeces

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sandra Barrios-de Pedro ◽  
Antonio Osuna ◽  
Ángela D. Buscalioni
Keyword(s):  
Early Cretaceous ◽  
Definitive Host ◽  
Helminth Eggs ◽  
Digenetic Trematodes ◽  
Fossil Site ◽  
Lacustrine Ecosystem

Abstract The exceptional fossil site of Las Hoyas (upper Barremian, Cuenca, Spain) yields abundant small to medium vertebrate coprolites, hindering the search for parasites. We studied the contents of 29 coprolites that were previously classified into distinct morphotypes. Several parasitic eggs were retrieved from two of these coprolites, confirming the second record of digenea trematode eggs and nematode (ascaridid) eggs from an Early Cretaceous locality. The cylindrical coprolite containing anisakid eggs was likely produced by a crocodylomorph as the parasite host, whereas the bump-headed lace coprolite indicates the role of a fish as an intermediary or definitive host of the trematodes and ascaridids. These trace and body fossils show that the Las Hoyas 126–129 Ma lacustrine ecosystem documents the early connection between basal Gonorynchiformes fish and digenetic trematodes.

Role of cats in human toxocarosis

2020 ◽  
Vol 11 (9) ◽  
pp. 400-408
Author(s):  
Pablo David Jimenez Castro ◽  
Sarah GH Sapp
Keyword(s):  
Definitive Host ◽  
Human Disease ◽  
Clinical Signs ◽  
Toxocara Canis ◽  
Infection Risk ◽  
Domestic Cats ◽  
Toxocara Cati ◽  
Related Disease ◽  
Paratenic Hosts

Toxocara cati, the feline ascarid, is ubiquitous in domestic cats globally and is increasingly recognised as an important zoonotic species. In the definitive host, infections with the adult ascarid usually do not present any clinical signs; if clinical signs do appear, it is usually in kittens infected with T. cati, especially by the trans-mammary route. Diseases may include cachexia, a pot-bellied appearance, respiratory disorders, diarrhoea, vomiting, among other signs, and these may present as early as 3 weeks of age. However, infections with Toxocara spp. larvae in paratenic hosts (including humans and many other animals), can result in serious complications from the migration of larvae. Historically, there has been an assumption that Toxocara canis was the most likely cause of Toxocara spp.-related disease; while it is probably true that T. canis is responsible for the majority of infections, it is important that those caused by T. cati are accurately identified so that the contribution of this parasite to human disease can be established and then handled appropriately. Overall, the detection of infections in cats and the control of parasite stages in the environment are essential to minimise the infection risk to other animals or humans.

scholarly journals Numerical Calculation of Sink Velocities for Helminth Eggs in Water

Computation ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 136
Author(s):  
Ali Cemal Benim
Keyword(s):  
Fluid Dynamics ◽  
Steady State ◽  
Numerical Calculation ◽  
Tap Water ◽  
Problem Formulation ◽  
General Purpose ◽  
Ansys Fluent ◽  
Helminth Eggs

The settling velocities of helminth eggs of three types, namely Ascaris suum (ASC), Trichuris suis (TRI), and Oesophagostomum spp. (OES), in clean tap water are computationally determined by means of computational fluid dynamics, using the general-purpose CFD software ANSYS Fluent 18.0. The previous measurements of other authors are taken as the basis for the problem formulation and validation, whereby the latter is performed by comparing the predicted sink velocities with those measured in an Owen tube. To enable a computational treatment, the measured shapes of the eggs are parametrized by idealizing them in terms of elementary geometric forms. As the egg shapes show a variation within each class, “mean” shapes are considered. The sink velocities are obtained through the computationally obtained drag coefficients. The latter are defined by means of steady-state calculations. Predicted sink velocities are compared with the measured ones. It is observed that the calculated values show a better agreement with the measurements, for ASC and TRI, compared to the theoretical sink values delivered by the Stokes theory. However, the observed agreement is still found not to be very satisfactory, indicating the role of further parameters, such as the uncertainties in the characterization of egg shapes or flocculation effects even in clean tap water.

scholarly journals Infections of Digenetic Trematode Metacercariae in Wrestling Halfbeak, Dermogenys pusilla from Bangkok Metropolitan Region in Thailand

2020 ◽  
Vol 58 (1) ◽  
pp. 27-35 ◽  
Author(s):  
Laddawan Patarwut ◽  
Thapana Chontananarth ◽  
Jong-Yil Chai ◽  
Watchariya Purivirojkul
Keyword(s):  
Metropolitan Region ◽  
Digenetic Trematode ◽  
Head Part ◽  
Intermediate Hosts ◽  
Mean Intensity ◽  
Digenetic Trematodes ◽  
The Mean ◽  
Study Sites ◽  
Digestion Methods

This study aimed to investigate metacercarial infections in the wrestling halfbeak, <i>Dermogenys pusilla</i>, collected from Bangkok metropolitan region of Thailand. A total of 4,501 fish from 78 study sites were commonly examined with muscle compression and digestion methods (only head part of fish) during September 2017 to July 2018. The overall prevalence of metacercarial infection was 86.1% (3,876/4,501 individuals), and the mean intensity was 48.9 metacercariae per fish infected. Four species, i.e., <i>Posthodiplostomum</i> sp., <i>Stellantchasmus falcatus</i>, Cyathocotylidae fam. sp., and <i>Centrocestus formosanus</i>, of digenetic trematode metacercariae (DTM) were detected. The prevalences were 65.8%, 52.0%, 2.1%, and 1.2%, respectively and their mean intensities were 23.1, 51.6, 1.4, and 3.2 per fish infected, respectively. The seasonal prevalences were 81.0% in winter, 87.8% in summer and 87.4% in rainy, and the mean intensities were 38.9, 46.6, and 55.2 metacercariae per fish infected, respectively. Conclusively, it was confirmed that the wrestling halfbeak play the role of second intermediate hosts of 4 species of digenetic trematodes including <i>S. falcatus</i> and <i>Posthodiplostomum</i> sp. in Bangkok metropolitan region. And then the metacercariae of <i>C. formosanus</i> and Cyathocotylidae fam. sp. are to be first found in the wrestling halfbeak by this study.

scholarly journals Levels of changes in the genus Pinus Linné in the composition of Mesozoic and Cenozoic flora and vegetation as an additional criterion for the division of sediments by the Mesozoic and Cenozoic of Ukraine

2021 ◽  
Vol 30 (4) ◽  
pp. 741-753
Author(s):  
Olena A. Sirenko ◽  
Olena A. Shevchuk
Keyword(s):  
Species Diversity ◽  
Early Cretaceous ◽  
Late Jurassic ◽  
Middle Miocene ◽  
Geological Time ◽  
Tectonic Structures ◽  
Historical Aspect ◽  
Quantitative Changes ◽  
Cenozoic Sediments

The article presents an analysis of a large array of results of palynological studies of Mesozoic and Cenozoic sediments of Ukraine and adjacent regions of Belarus and Russia. Numerous literature data on the palynological characteristics of Meso-Cenozoic sediments and the materials of the authors are summarized according to the results of spore-pollen analysis of Mesozoic and Cenozoic sediments within the main tectonic structures of Ukraine. It has been established that the genus Pinus (Pinaceae) is an integral part of the Meso-Cenozoic flora of Ukraine. Although, the participation in the flora and vegetation of the genus Pinus and its species diversity in different periods of geological time were different. Despite the long history and significant achievements of palynological research of Meso-Cenozoic sediments of Ukraine, no attention has been paid to the historical aspect of Pinus development in the Meso-Cenozoic flora. This work is presented as the first stem to fill this gap. The genus Pinus has a large stratigraphic range, but its species diversity and quantitative changes in the composition of Mesozoic and Cenozoic flora of different ages are markedly different. The analysis of these changes made it possible to trace the emergence and main levels at which the species composition was renewed and the role of Pinus in flora increased during the Mesozoic and Cenozoic. According to the results of the research, 5 levels of increasing the participation of the genus Pinus and changes in its species affiliation in the Mesozoic flora were established: Aalenian period of the Middle Jurassic (appearance of the first representatives of Pinus); Oxfordian time of the Late Jurassic; Valanginian – Early Barremian times of the Early Cretaceous; Albian time of the Early Cretaceous; Late Campanian time of the Late Cretaceous. 5 levels of increasing the role of Pinus and its species diversity for the flora and vegetation of the Cenozoic were also established: Oligocene time of the Paleogene, Konkian-early Sarmatian time of the Middle Miocene; early Pontian (Ivankov) time of the Late Miocene; early Kimmerian time (early Sevastopol) of the Early Pliocene and Martonosha time of the Early Neopleistocene. Certain levels have been traced for the similar age of Cenozoic flora of Belarus and Russia.

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