Population genetics of Parascaris equorum based on DNA fingerprinting

Tydén, Eva; Morrison, David A.; Engström, Annie; Nielsen, Martin K.; Eydal, Matthías; Höglund, Johan

doi:10.1016/j.meegid.2012.09.022

Cited by 17 publications

(10 citation statements)

References 39 publications

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“…Low nucleotide diversity was observed in B. schroederi and this revealed a relative lack of genetic variation across the ascaridoid, regardless of geographical origin and population size. Interestingly, similar findings were also described for other Ascaris species, including Ascaris galli [ 50 ], Ascaris suum [ 60 , 61 ] and Parascaris equorum [ 51 ]. Together, these results implied that low level of diversity may be a common feature of ascaridoid nematodes.…”

Section: Discussionsupporting

confidence: 82%

“…More importantly, a better understanding of parasitic nematode population dynamics is fundamental to design new strategies to monitor and control these problematic organisms. Excitingly, many recent studies have used genetic markers (e.g., mitochondrial and nuclear DNA) to depict geographical movements of parasitic nematodes [ 49 - 51 ]. MtDNA markers are receiving increased attention for this purpose due to higher F st values than observed for nuclear DNA counterparts [ 31 - 33 , 52 , 53 ].…”

Section: Discussionmentioning

confidence: 99%

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Absence of genetic structure in Baylisascaris schroederi populations, a giant panda parasite, determined by mitochondrial sequencing

Xie

Zhou²,

Zhang

et al. 2014

Parasites Vectors

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BackgroundInfection with the parasitic nematode, Baylisascaris schroederi (Ascaridida: Nematoda), is one of the most important causes of death in giant pandas, and was responsible for half of deaths between 2001 and 2005. Mitochondrial (mt) DNA sequences of parasites can unveil their genetic diversity and depict their likely dynamic evolution and therefore may provide insights into parasite survival and responses to host changes, as well as parasite control.MethodsBased on previous studies, the present study further annotated the genetic variability and structure of B. schroederi populations by combining two different mtDNA markers, ATPase subunit 6 (atp6) and cytochrome c oxidase subunit I (cox1). Both sequences were completely amplified and genetically analyzed among 57 B. schroederi isolates, which were individually collected from ten geographical regions located in three important giant panda habitats in China (Minshan, Qionglai and Qinling mountain ranges).ResultsFor the DNA dataset, we identified 20 haplotypes of atp6, 24 haplotypes of cox1, and 39 haplotypes of atp6 + cox1. Further haplotype network and phylogenetic analyses demonstrated that B. schroederi populations were predominantly driven by three common haplotypes, atp6 A1, cox1 C10, and atp6 + cox1 H11. However, due to low rates of gene differentiation between the three populations, both the atp6 and cox1 genes appeared not to be significantly associated with geographical divisions. In addition, high gene flow was detected among the B. schroederi populations, consistent with previous studies, suggesting that this parasite may be essentially homogenous across endemic areas. Finally, neutrality tests and mismatch analysis indicated that B. schroederi had undergone earlier demographic expansion.ConclusionsThese results confirmed that B. schroederi populations do not follow a pattern of isolation by distance, further revealing the possible existence of physical connections before geographic separation. This study should also contribute to an improved understanding of the population genetics and evolutionary biology of B. schroederi and assist in the control of baylisascariasis in giant pandas.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-014-0606-3) contains supplementary material, which is available to authorized users.

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Section: Discussionsupporting

confidence: 82%

Section: Discussionmentioning

confidence: 99%

Absence of genetic structure in Baylisascaris schroederi populations, a giant panda parasite, determined by mitochondrial sequencing

Xie

Zhou²,

Zhang

et al. 2014

Parasites Vectors

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“…A recent karyotype investigation of worm specimens and ascarid eggs obtained from faecal samples collected from foals in Central Kentucky identified only P. univalens (Nielsen et al 2014a). Further, a recent study of the population structure among about 200 equine ascarid specimens collected in Sweden, Norway, Germany, Iceland, Brazil and USA concluded that all specimens were genetically homogenous (Tyden et al 2013), and one of the US isolates collected for this study was later identified to be P. univalens.…”

Section: Introductionmentioning

confidence: 62%

“…Further, a recent study of the population structure among about 200 equine ascarid specimens collected in Sweden, Norway, Germany, Iceland, Brazil and USA concluded that all specimens were genetically homogenous (Tyden et al . ), and one of the US isolates collected for this study was later identified to be P. univalens . Thus, it appears that P. univalens is uniformly found in horses all over the world, whereas it remains an open question whether P. equorum may still be encountered and, if so, where.…”

Section: Introductionmentioning

confidence: 97%

Evidence‐based considerations for control of Parascaris spp. infections in horses

Nielsen

2015

Equine Veterinary Education

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Summary Parascaris spp. infection is virtually ubiquitous in young foals and worm burdens can achieve high numbers. The most important disease manifestation is impaction of the small intestine, which occurs in a small proportion of infected foals but is associated with a guarded prognosis for survival. Control of Parascaris spp. is complicated by emerging resistance to currently available anthelmintic drug classes. Resistance to macrocyclic lactones has been reported worldwide and a few studies have also documented signs of resistance to pyrantel salts and benzimidazoles. Foals generally develop immunity to Parascaris spp. parasites around age 6 months, but a proportion of weanlings and yearlings can harbour smaller burdens at age 8–10 months. Older horses have occasionally been reported with substantial ascarid burdens as well. Qualitative detection of ascarid eggs has good diagnostic value whereas an actual egg count does not correlate well with the size of the worm burden. A recent investigation documented the applicability of a transabdominal ultrasound technique for semiquantitatively monitoring ascarid burdens in foals. Control of ascarids is complicated by the limited drug classes available for treating this parasite, and by the fact that foals are often concurrently infected with strongyles. In many cases, none of the 3 available anthelmintic classes are simultaneously effective against both parasite groups, so close monitoring is required to select the most appropriate anthelmintic in each case.

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“…Independent evidence of ivermectin resistant Parascaris spp. populations have also been accumulating in recent years (Laugier et al, 2012; Lyons et al, 2008; Tyden et al, 2013). However, the quantification of parasitic community evolution through time remains difficult and limited reports have been made so far.…”

Section: Introductionmentioning

confidence: 99%

Compilation of 29-yearpostmortemexaminations identifies major shifts in equine parasite prevalence from 2000 onwards

Sallé

Guillot

Tapprest

et al. 2019

Preprint

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0Horses are infected by a wide range of parasite species that form complex communities. 1Parasite control imposes significant constraints on parasite species assemblage whose 2 2 monitoring remains however difficult to track through time. Postmortem examination is a 2 3 reliable method to quantify parasite communities. Here, we compiled 1,673 necropsy reports 2 4 accumulated over 29 years, in the reference necropsy centre from Normandy (France). The 2 5 burden of non-strongylid species was quantified. Details of horse deworming history and the 2 6 cause of death (resulting from a parasitic infection or not) were registered. Data analyses 2 7 revealed the seasonal fluctuations of non-strongylid parasite species and the least exposure 2 8of race horses to these parasites. Beyond these observations, we found a shift in the species 2 9 responsible for fatal parasitic infection from the year 2000 onward, whereby fatal 3 0 cyathostominosis and Parascaris spp. infection have replaced death cases caused by S. 3 1 vulgaris and tapeworms. Concomitant break in the temporal trend of parasite species 3 2prevalence was also found within a 10-year window (1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)) that has seen the rise of 3 3Parascaris spp. and the decline of both Gasterophilus spp. and tapeworms. A few cases of 3 4 parasite persistence following deworming were identified that all occurred after 2000.3 5Altogether, these findings provide a unique assessment of the major remodelling of equine 3 6 parasitic communities over the last 29 years. They also underscore the critical importance of 3 7Parascaris spp. in young equids.3 8 3 9

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Population genetics of Parascaris equorum based on DNA fingerprinting

Cited by 17 publications

References 39 publications

Absence of genetic structure in Baylisascaris schroederi populations, a giant panda parasite, determined by mitochondrial sequencing

Absence of genetic structure in Baylisascaris schroederi populations, a giant panda parasite, determined by mitochondrial sequencing

Evidence‐based considerations for control of Parascaris spp. infections in horses

Compilation of 29-yearpostmortemexaminations identifies major shifts in equine parasite prevalence from 2000 onwards

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