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Eosinophils are important immune cells that have been implicated in resistance to gastrointestinal nematode (GIN) infections in both naturally and experimentally infected sheep. Proteins of particular importance appear to be IgA-Fc alpha receptor (FcαRI), C-C chemokine receptor type 3 (CCR3), proteoglycan 3 (PRG3, major basic protein 2) and EPX (eosinophil peroxidase). We used known human nucleotide sequences to search the ruminant genomes, followed by translation to protein and sequence alignments to visualize differences between sequences and species. Where a sequence was retrieved for cow, but not for sheep and goat, this was used additionally as a reference sequence. In this review, we show that eosinophil function varies among host species. Consequently, investigations into the mechanisms of ruminant immune responses to GIN should be conducted using the natural host. Specifically, we address differences in protein sequence and structure for eosinophil proteins.
The genetic variation and taxonomic status of the four morphologically-defined species of Macropostrongyloides in Australian macropodid and vombatid marsupials were examined using sequence data of the ITS+ region (=first and second internal transcribed spacers, and the 5.8S rRNA gene) of the nuclear ribosomal DNA. The results of the phylogenetic analyses revealed that Ma. baylisi was a species complex consisting of four genetically distinct groups, some of which are host-specific. In addition, Ma. lasiorhini in the common wombat (Vombatus ursinus) did not form a monophyletic clade with Ma. lasiorhini from the southern hairy-nosed wombat (Lasiorhinus latifrons), suggesting the possibility of cryptic (genetically distinct but morphologically similar) species. There was also some genetic divergence between Ma. dissimilis in swamp wallabies (Wallabia bicolor) from different geographical regions. In contrast, there was no genetic divergence among specimens of Ma. yamagutii across its broad geographical range or between host species (i.e. Macropus fuliginosus and M. giganteus). Macropostrongyloides dissimilis represented the sister taxon to Ma. baylisi, Ma. yamagutii and Ma. lasiorhini. Further morphological and molecular studies are required to assess the species complex of Ma. baylisi.
This study assessed the in vitro anthelmintic (AH) activity of methanol and acetone:water leaf extracts from Annona squamosa, A. muricata and A. reticulata against Haemonchus contortus eggs. The egg hatch test was used to determine the effective concentrations required to inhibit 50% of eggs hatching (EC50). The role of polyphenols on AH activity was measured through bioassays with and without polyvinylpolypyrrolidone (PVPP). Methanolic extracts mainly caused the death of eggs at the morula stage (ovicidal activity). Meanwhile, acetone:water extracts caused egg-hatching failure of developed larvae (larvae failing eclosion (LFE) activity). The lowest EC50 values against H. contortus eggs were observed for the methanolic extracts from A. reticulata and A. muricata (274.2 and 382.9 µg/ml, respectively). From the six extracts evaluated, the methanolic extracts of A. muricata, A. reticulata and A. squamosa showed the highest ovicidal activity, resulting in 98.9%, 92.8% and 95.1% egg mortality, respectively. When the methanolic extract of A. squamosa was incubated with PVPP, its AH activity increased. Similarly, when acetone:water extracts of A. muriata and A. reticulata were incubated with PVPP, their LFE activity increased. Alkaloids were only evident in methanolic extracts, irrespective of PVPP incubation. The presence of acetogenins was not observed. In conclusion, methanolic extracts obtained from leaves of A. muricata, A. reticulata and A. squamosa showed ovicidal activity affecting the morula of H. contortus eggs, with minor LFE activity. Meanwhile, acetone:water extracts showed mostly LFE activity, with a lower proportion of ovicidal activity.
Meloidogyne paranaensis is responsible for considerable losses in coffee production. Because of the distribution of this species in the main Coffea arabica producing regions, there is a need for management practices to ensure the sustainability of coffee production. In this work, we evaluated the agronomic performance of resistant clones of the Conilon coffee cultivar Vitoria Incaper 8142 in areas infested by M. paranaensis in the west region of Minas Gerais, Brazil. Clones 2V, 3V, and 6V presented the lowest number of nematodes per gram of roots and were considered resistant to M. paranaensis. All other clones were considered tolerant to this nematode, and one had good vegetative growth but allowed nematode reproduction. Clones of Vitoria Incaper 8142 of C. canephora represent an alternative to coffee production in areas infested by M. paranaensis including areas traditionally cultivated with C. arabica.
Cosmopolitan habitat-forming taxa of algae such as the genus Corallina provide an opportunity to compare patterns of biodiversity over wide geographic scales. Nematode assemblages inhabiting Corallina turves were compared between the south coasts of the British Isles and South Korea. A fully nested design was used with three regions in each country, two shores in each region and replicate samples taken from three patches on each shore to compare differences in the taxonomic and biological trait composition of nematode assemblages across scales. A biological traits approach, based on functional diversity of nematodes, was used to make comparisons between countries, among regions, between shores and among patches. The taxonomic and biological trait compositions of nematode assemblages were significantly different across all spatial scales (patches, shores, regions and countries). There is greater variation amongst nematode assemblages at the scale of shore than at other spatial scales. Nematode assemblage structure and functional traits are influenced by the local environmental factors on each shore including sea-surface temperature, the amount of sediment trapped in Corallina spp. and tidal range. The sea-surface temperature and the amount of sediment trapped in Corallina spp. were the predominant factors determining nematode abundance and composition of assemblages and their functional diversity.
The gastrointestinal nematodes (GIN) stand out as an important cause of disease in small ruminant, especially on goat farm. Widespread resistance to synthetic anthelminthics has stimulated the research for alternative strategies of parasite control, including the use of medicinal plants. The present work summarizes the in vitro and in vivo studies of plants with activity against GIN of goats, focusing on the description of chemical constituents related to this effect. This review retrieved 56 scientific articles from 2008 to 2018 describing more than 100 different plant species. The most frequently investigated family was Fabaceae (30.7%). Most in vitro studies on the activity of plant extracts and fractions were carried out with of free-living stages nematodes. In vivo studies were conducted mainly with the use of plants in animal feed and generally showed lower effectiveness compared to in vitro assays. The main plant secondary metabolites associated with anthelmintic effect are condensed tannins, saponin and flavonoids. However, the studies with compounds isolated from plants and elucidation of their mechanisms of action are scarce. Herbal medicines are thought to be promising sources for the development of effective anthelmintic agents.
Strongyloides stercoralis is a neglected parasite that can cause death in immunocompromised individuals. There were no data on the epidemiology of S. stercoralis infection in San Marino Republic until two patients (one of whom died) were diagnosed with severe strongyloidiasis (hyperinfection) between September 2016 and March 2017. A serology test for Strongyloides spp. was introduced in routine practice in the laboratory of the State Hospital to test patients considered to be at risk for strongyloidiasis. Between August 2017 and August 2018, of 42 patients tested with serology, two (4.8%) were positive. An additional case was found by gastric biopsy. Two of the positive cases were presumably autochthonous infections (elderly people with no significant travel history), while the other was a probable imported case (young man born in Nigeria and settled in Europe since 2003). Epidemiology of strongyloidiasis in San Marino might be similar to Northern Italy, where a relevant proportion of cases was diagnosed in immigrants (mainly from sub-Saharan Africa) and in elderly Italians with eosinophilia. Screening for strongyloidiasis might be worthwhile in inhabitants of San Marino in the same categories of individuals, particularly those at risk of immune suppression.
Gastrointestinal nematodes significantly affect the ovine industry, and Haemonchus contortus is considered the most pathogenic parasite in tropical regions. This situation is aggravated when the main strategy to control worms fails because of the genetic resistance that parasites acquire against anthelmintics. Aiming to anticipate the events involved in anthelmintic resistance, we induced monepantel resistance in H. contortus by in vivo subdosing of sheep hosts. Four successive passages of a monepantel-susceptible H. contortus isolate in Santa Ines or Ile de France sheep hosts resulted in three monepantel-resistant (efficacy varying from 0 to 58.5%) H. contortus isolates. Sheep hosts were treated from 0.075 mg/kg to the therapeutic dose of 2.5 mg/kg of monepantel in 19–26 rounds of selection for 112–133 weeks. Success in inducing H. contortus resistance to monepantel may have been affected by worm burden and by host–parasite interactions, including a possible effect of the breed of sheep hosts. We conclude that subdosing of sheep, although time-consuming, is an efficient in vivo strategy for the induction of monepantel resistance in H. contortus. The resistant parasites can be used in further studies to elucidate the genetic and biochemical events involved in the acquisition of anthelmintic resistance.
In the search for alternative practices to chemical soil fumigation (CSF), anaerobic soil disinfestation (ASD) has proven to be a promising tool for soil-borne pest management and crop production improvement. The ASD treatment with composted poultry litter (CPL) and molasses (M, a labile carbon source) was identified as an effective approach for a biologically based soil disinfestation system in tomato (Solanum lycopersicum L.) production in Florida. However, environmental and food-safety concerns are associated with animal manure-based amendments, which led to the exploration of composted yard waste (CYW) as a potential substitute for CPL in ASD application. In this study, field trials were conducted in Citra and Immokalee, FL to examine the effects of ASD using CYW, CPL and M compared with a commercially available microbial amendment system on root-knot nematodes, weeds, fruit yield and quality of fresh-market tomato. Treatments included (1) ASD with CPL (11 Mg ha−1) and M (6.9 m3 ha−1) (ASD0.5), (2) ASD with CYW (26.9 Mg ha−1) and M (CYW1 + M), (3) ASD with CYW (13.5 Mg ha−1) and M (CYW0.5 + M), (4) Soil Symphony Amendment (SSA), (5) CYW (26.9 Mg ha−1) alone (CYW1) and (6) a combination of CYW1 + SSA, in comparison with (7) untreated control and (8) CSF (Pic-Clor 60 at 224 kg ha−1). Cumulative soil anaerobiosis was greater in ASD0.5 compared with all the other treatments. The root-knot nematode gall index ratings on the tomato crop were significantly lower in CSF, ASD0.5, CYW1 + M and CYW0.5 + M than untreated control in Citra. Although CYW1 and SSA alone had a moderately suppressive effect on weed coverage and root-knot nematodes, their positive impact on crop performance was limited when used alone. ASD0.5, CYW1 + M and CSF had significantly higher marketable and total fruit yields than untreated control in both locations, while all treatments showed promising results in the Immokalee trial in comparison with untreated control. In general, few differences in major fruit quality attributes were found. Although using CYW in ASD was not as effective as CPL in creating soil anaerobic conditions, the enhanced crop performance in CYW1 + M and CYW0.5 + M suggests the potential of using CYW as an alternative source of organic amendment in combination with M to achieve benefits similar to those obtained with CPL-based ASD.
Phasmarhabditis hermaphrodita is a parasitic nematode of terrestrial gastropods that has been formulated into a biological control agent for farmers and gardeners to kill slugs and snails. In order to locate slugs it is attracted to mucus, faeces and volatile cues; however, there is no information about whether these nematodes are attracted to snail cues. It is also unknown how wild isolates of P. hermaphrodita or different Phasmarhabditis species behave when exposed to gastropod cues. Therefore, we investigated whether P. hermaphrodita (commercial and wild isolated strains), P. neopapillosa and P. californica were attracted to mucus from several common snail species (Cepaea nemoralis, Cepaea hortensis, Arianta arbustorum and Cornu aspersum). We also examined whether snails (C. aspersum) collected from different locations around the UK differed in their attractiveness to wild isolates of P. hermaphrodita. Furthermore, we also investigated what properties of snail mucus the nematodes were attracted to, including hyaluronic acid and metal salts (FeSO4, ZnSO4, CuSO4 and MgSO4). We found that the commercial strain of P. hermaphrodita responded poorly to snail mucus compared to wild isolated strains, and C. aspersum collected from different parts of the UK differed in their attractiveness to the nematodes. We found that Phasmarhabditis nematodes were weakly attracted to all metals tested but were strongly attracted to hyaluronic acid. In a final experiment we also showed that pharmacological manipulation of cyclic guanosine monophosphate (cGMP) increased chemoattraction to snail mucus, suggesting that the protein kinase EGL-4 may be responsible for Phasmarhabditis sp. chemoattraction.
Control of equine nematodes has relied on benzimidazoles (BZs), tetrahydropyrimidines and macrocyclic lactones. The intensive use of anthelmintics has led to the development of anthelmintic resistance (AR) in equine cyathostomins and Parascaris equorum. Field studies indicate that BZ and pyrantel resistance is widespread in cyathostomins and there are also increasing reports of resistance to macrocyclic lactones in cyathostomins and P. equorum. The unavailability of reliable laboratory-based techniques for detecting resistance further augments the problem of nematode control in horses. The only reliable test used in horses is the fecal egg count reduction test; therefore, more focus should be given to develop and validate improved methodologies for diagnosing AR at an early stage, as well as determining the mechanisms involved in resistance development. Therefore, equine industry and researchers should devise and implement new strategies for equine worm control, such as the use of bioactive pastures or novel feed additives, and control should increasingly incorporate alternative and evidence-based parasite control strategies to limit the development of AR. This review describes the history and prevalence of AR in equine nematodes, along with recent advances in developing resistance diagnostic tests and worm control strategies in horses, as well as giving some perspective on recent research into novel control strategies.
The importance of parasites as a selective force in host evolution is a topic of current interest. However, short-term ecological studies of host–parasite systems, on which such studies are usually based, provide only snap-shots of what may be dynamic systems. We report here on four surveys, carried out over a period of 12 years, of helminths of spiny mice (Acomys dimidiatus), the numerically dominant rodents inhabiting dry montane wadis in the Sinai Peninsula. With host age (age-dependent effects on prevalence and abundance were prominent) and sex (female bias in abundance in helminth diversity and in several taxa including Cestoda) taken into consideration, we focus on the relative importance of temporal and spatial effects on helminth infracommunities. We show that site of capture is the major determinant of prevalence and abundance of species (and higher taxa) contributing to helminth community structure, the only exceptions being Streptopharaus spp. and Dentostomella kuntzi. We provide evidence that most (notably the Spiruroidea, Protospirura muricola, Mastophorus muris and Gongylonema aegypti, but with exceptions among the Oxyuroidae, e.g. Syphacia minuta), show elements of temporal-site stability, with a rank order of measures among sites remaining similar over successive surveys. Hence, there are some elements of predictability in these systems.
Orca (Orcinus orca) strandings are rare and post-mortem examinations on fresh individuals are scarce. Thus, little is known about their parasitological fauna, prevalence of infections, associated pathology and the impact on their health. During post-mortem examinations of two male neonatal orcas stranded in Germany and Norway, lungworm infections were found within the bronchi of both individuals. The nematodes were identified as Halocercus sp. (Pseudaliidae), which have been described in the respiratory tract of multiple odontocete species, but not yet in orcas. The life cycle and transmission pathways of some pseudaliid nematodes are incompletely understood. Lungworm infections in neonatal cetaceans are an unusual finding and thus seem to be an indicator for direct mother-to-calf transmission (transplacental or transmammary) of Halocercus sp. nematodes in orcas.
Here, we describe a new microsporidium Percutemincola moriokae gen. nov., sp. nov., which was discovered in the intestinal and hypodermal cells of a wild strain of the nematode Oscheius tipulae that inhabits in the soil of Morioka, Iwate Prefecture, Japan. The spores of Pe. moriokae had an average size of 1.0 × 3.8 µm and 1.3 × 3.2 µm in the intestine and hypodermis, respectively, and electron microscopy revealed that they exhibited distinguishing features with morphological diversity in the hypodermis. Isolated spores were able to infect a reference strain of O. tipulae (CEW1) through horizontal transmission but not the nematode Caenorhabditis elegans. Upon infection, the spores were first observed in the hypodermis and then in the intestine the following day, suggesting a unique infectious route among nematode-infective microsporidia. Molecular phylogenetic analysis grouped this new species with the recently identified nematode-infective parasites Enteropsectra and Pancytospora forming a monophyletic sister clade to Orthosomella in clade IV, which also includes human pathogens such as Enterocytozoon and Vittaforma. We believe that this newly discovered species and its host could have application as a new model in microsporidia–nematode association studies.
Over a century ago microfaunal diversity was first recorded by James Murray in lakes at Cape Royds, Ross Island, Antarctica. The report stands as the seminal study for today’s biodiversity investigations, and as a baseline to evaluate changes in faunal communities and introductions. In the present study, Cape Royds lakes were revisited and the mitochondrial c oxidase subunit I (COI) gene and morphology were used to compare diversity of Rotifera, Tardigrada and Nematoda with the records Murray published in the early 1900s. Cyanobacterial mats and the water column were sampled for microfauna from the five largest lakes using methods described by Murray. Across all five lakes similar patterns were observed for species distribution of all three phyla reported by Murray over 100 years ago. Some changes in species assemblages were identified within and between lakes, but there were no new introductions of named species for the Cape Royds region. Some of the species included by Murray in his monograph have been recently redescribed as Antarctic endemics, but others still retain their original name from the Northern Hemisphere holotypes and are also in need of revision to adequately determine the true endemism for these faunal groups.
Northern bobwhite quail (Colinus virginianus), a popular gamebird among hunters, have been declining over recent decades in the Rolling Plains ecoregion. Investigations in the past few years have revealed a high prevalence of eyeworms (Oxyspirura petrowi) and caecal worms (Aulonocephalus pennula) in this ecoregion, prompting a need to better understand their host–parasite interaction and other factors that influence infection. In this study, the efficiency of a mobile laboratory was tested by deploying it to three field sites in the Rolling Plains between July and August of 2017 and collecting cloacal swabs from bobwhites. The DNA was extracted from swabs for quantitative PCR and was run in the mobile and reference laboratory to specifically detect A. pennula and O. petrowi infection. When compared with the Wildlife Toxicology's reference laboratory, the mobile laboratory had a 97 and 99% agreement for A. pennula and O. petrowi, respectively. There were no significant differences in infection levels between field sites. Due to its efficiency, it is proposed that the mobile laboratory would be an effective way to monitor infection levels, in addition to factors that may affect infection such as climate, diapause, and intermediate host populations.
In Tunisia and other North African countries, there is a lack of knowledge about parasite biodiversity within threatened wild ruminants and there are not any studies on their gastrointestinal nematodes. Thus the aim of this study was to identify gastrointestinal fauna in the faecal samples of Tunisian wild ruminants. A total of 262 faecal samples were collected from domestic sheep and goat, and wild ruminants (Addax, Barbary sheep, Barbary red deer, Dorcas gazelle, Slender-horned gazelle and Scimitar-horned Oryx) living in protected areas. Samples were examined with floatation (saturated sodium chloride solution), polymerase chain reaction and sequencing of the second internal transcribed spacer region of the rDNA. Microscopic analysis allowed the identification of only Nematodirus genus or molecular tools allowed a first identification of five gastrointestinal nematode species in North African wild ruminants: Chabertia ovina (1.6%), Camelostrongylus mentulatus (1.6%), Marshallagia marshalli (4.7%), Nematodirus helvetianus (62.5%) and Nematodirus spathiger (29.7%). This study reported the first records of C. mentulatus and M. marshalli in Addax and of M. marshalli in Dorcas gazelle and it was the first reported record of N. helvetianus and M. marshalli in Tunisia.
This study presents patterns of spatial and temporal variation in the meiofaunal community and nematode associations on the volcanic sandy beaches of Trindade Island, a remote oceanic island in the South-east Atlantic Ocean. Samples were collected in August (rainy season) and December 2014 (dry season) on four beaches (Tartarugas, Parcel, Cabritos and Portugueses) at three zones of the intertidal (high, mid and low). A total of 10 meiofaunal groups were found. Copepods (31%) and nematodes (27%) dominated the meiofauna in all beaches and zones, regardless of the season. Nematodes were comprised mainly of non-selective deposit feeders, with a total of 27 genera from 12 families, with Cyatholaimidae, Xyalidae and Oncholaimidae as the most diverse and abundant. Significant differences were found in the meiofaunal community, as well as in nematode associations, among seasons and intertidal zones but not among beaches. The sediment characteristics were the main drivers regulating the structure of meiobenthic fauna in Trindade Island. Our findings are also compared to other studies focusing on the meiofauna and nematodes of oceanic islands with carbonate and volcanic sediments; the major patterns are herein presented.
The suitability of a single mid-season targeted selective treatment (TST) for gastrointestinal nematodes control, based on flexible average daily weight gain (ADWG) thresholds, was investigated in 23 groups of first grazing season calves. In each group, animals were weighed three times: before turnout, at mid-season and at housing. Just after the first weighing, each group was divided in two homogenous sub-groups in terms of age, breed and weight, and randomly allocated to one of two sub-groups intented for two different mid-season anthelmintic treatment strategies: (1) a treatment of all calves composing the sub-group (whole-group treatment (WT)) or (2) a targeted selective weight gain-based treatment (TST) of the animals showing an individual pre-treatment ADWG inferior to the mean pre-treatment ADWG of the corresponding WT sub-group. Anthelmintic treatment (levamisole 7.5 mg/kg BW) was performed 3 to 4 months after turnout. At housing, two parasitological parameters (the anti-Ostertagia ostertagi antibody level-Ostertagia optical density ratio (ODR) and the pepsinogen level) and a clinical parameter (the breech soiling score) were assessed at individual level in each group. Then, the high exposed groups to gastrointestinal nematode (GIN) were defined as groups for which untreated animals exhibited a mean Ostertagia ODR ⩾0.7 and among these groups, the ones characterized by high abomasal damage due to Ostertagia for which untreated animals exhibited a mean pepsinogen level ⩾2.5 U Tyr were also identified. Among TST sub-groups, the treatment ADWG thresholds varied from 338 to 941 g/day and the percentage of treated animals from 28% to 75%. Pre- and post-treatment ADWG as well as parasitological and clinical parameters measured at housing were similar between TST and WT sub-groups including the 17 high exposed groups to GIN. Within these 17 groups, the treatment allowed to significantly improve post-treatment ADWG compared with untreated animals. In the six high exposed groups showing mean pepsinogen level ⩾2.5 U Tyr, the average effect of treatment on post-treatment ADWG was the highest and estimated up to 14 kg after a grazing duration of 4 months. In contrast, in six other groups showing mean Ostertagia ODR<0.7 in untreated animals, no effect of treatment was seen suggesting an absence of production losses related to a low level of GIN infection. This study highlighted the suitability of a convenient mid-season TST strategy for first grazing season calves, based on the use of flexible thresholds of ADWG, allowing similar growth compared with a whole-group treatment while keeping a GIN population in refugia.
Syphacia stroma (von Linstow, 1884) Morgan, 1932 and Syphacia frederici Roman, 1945 are oxyurid nematodes that parasitize two murid rodents, Apodemus sylvaticus and Apodemus flavicollis, on the European mainland. Only S. stroma has been recorded previously in Apodemus spp. from the British Isles. Despite the paucity of earlier reports, we identified S. frederici in four disparate British sites, two in Nottinghamshire, one each in Berkshire and Anglesey, Wales. Identification was based on their site in the host (caecum and not small intestine), on key morphological criteria that differentiate this species from S. stroma (in particular the tail of female worms) and by sequencing two genetic loci (cytochrome C oxidase 1 gene and a section of ribosomal DNA). Sequences derived from both genetic loci of putative British S. frederici isolates formed a tight clade with sequences from continental worms known to be S. frederici, clearly distinguishing these isolates from S. stroma which formed a tight clade of its own, distinct from clades representative of Syphacia obvelata from Mus and S. muris from Rattus. The data in this paper therefore constitute the first record of S. frederici from British wood mice, and confirm the status of this species as distinct from both S. obvelata and S. stroma.