Co-infection of Haemonchus contortus and Trichostrongylus spp. among livestock in Malaysia as revealed by amplification and sequencing of the internal transcribed spacer II DNA region

The identification of small molecule inhibitors with anthelmintic activities that target conserved proteins among ruminant gastrointestinal nematodes

Gastrointestinal nematode (GIN) infections are a major concern for the ruminant industry worldwide and result in significant production losses. Naturally occurring polyparasitism and increasing drug resistance that potentiate disease outcomes are observed among the most prevalent GINs of veterinary importance. Within the five major taxonomic clades, clade Va represents a group of GINs that predominantly affect the abomasum or small intestine of ruminants. However, the development of effective broad-spectrum anthelmintics against ruminant clade Va GINs has been challenged by a lack of comprehensive druggable genome resources. Here, we first assembled draft genomes for three clade Va species (Cooperia oncophora, Trichostrongylus colubriformis, and Ostertagia ostertagi) and compared them with closely related ruminant GINs. Genome-wide phylogenetic reconstruction showed a relationship among ruminant GINs structured by taxonomic classification. Orthogroup (OG) inference and functional enrichment analyses identified 220 clade Va-specific and Va-conserved OGs, enriched for functions related to cell cycle and cellular senescence. Further transcriptomic analysis identified 61 taxonomically and functionally conserved clade Va OGs that may function as drug targets for new broad-spectrum anthelmintics. Chemogenomic screening identified 11 compounds targeting homologs of these OGs, thus having potential anthelmintic activity. In in vitro phenotypic assays, three kinase inhibitors (digitoxigenin, K-252a, and staurosporine) exhibited broad-spectrum anthelmintic activities against clade Va GINs by obstructing the motility of exsheathed L3 (xL3) or molting of xL3 to L4. These results demonstrate valuable applications of the new ruminant GIN genomes in gaining better insights into their life cycles and offer a contemporary approach to discovering the next generation of anthelmintics.IMPORTANCEGastrointestinal nematode (GIN) infections in ruminants are caused by parasites that inhibit normal function in the digestive tract of cattle, sheep, and goats, thereby causing morbidity and mortality. Coinfection and increasing drug resistance to current therapeutic agents will continue to worsen disease outcomes and impose significant production losses on domestic livestock producers worldwide. In combination with ongoing therapeutic efforts, advancing the discovery of new drugs with novel modes of action is critical for better controlling GIN infections. The significance of this study is in assembling and characterizing new GIN genomes of Cooperia oncophora, Ostertagia ostertagi, and Trichostrongylus colubriformis for facilitating a multi-omics approach to identify novel, biologically conserved drug targets for five major GINs of veterinary importance. With this information, we were then able to demonstrate the potential of commercially available compounds as new anthelmintics.

Molecular and phylogenetic characterization of zoonotic Trichostrongylus species from goats for the first time in Bangladesh

BACKGROUND

Trichostrongylus is one of the most important nematodes infecting animals and humans. The current study was designed to identify the Trichostrongylus species infecting goats by multiplex PCR and phylogenetic analysis.

METHODS

A total of 124 goats' viscera were collected from different abattoirs of Mymensingh division. Trichostrongylus species were isolated and characterized based on morphometry, multiplex PCR and phylogenetic analysis.

RESULTS

Among 124 viscera of goats, 39 were positive with two species, Trichostrongylus colubriformis and Trichostrongylus vitrinus, revealing an overall 31.45% prevalence. Morphological identification of Trichostrongylus species was confirmed by multiplex PCR amplification of the ITS2 gene and sequencing. Partial sequencing of the ITS2 gene of two species revealed seven single nucleotide polymorphisms (three transitions and four transversions) in this study. The neighbor-joining phylogenetic tree demonstrated that T. colubriformis and T. vitrinus isolates were clustered together with the reference sequences that belong to the clade A and B without any geographical boundaries.

CONCLUSIONS

This is the first report on molecular and phylogenetic analysis of Trichostrongylus species from ruminants in Bangladesh. These results provide the baseline data for understanding the zoonosis and epidemiology of this parasite in Bangladesh and global perspectives.

Morphological and molecular characterization of Haemonchus contortus isolated from the small ruminants of south Gujarat, India

The successful design of strategic control measures against the blood-sucking gastrointestinal nematode, Haemonchus contortus in small ruminants can be facilitated by revealing its general features from morphology to the molecular level. In the south Gujarat region of India, a total of 2408 H. contortus were collected from 84 slaughtered sheep's abomasum, consisting of 347 males and 2061 females (1:6 ratio) (p<0.05). Furthermore, 726 H. contortus were collected from 61 goats, comprising 145 males and 581 females (1:4 ratio) (p<0.05). The male worms were approximately 12±0.06 mm long, while female worms were about 20±0.09 mm long. The vulvar morphotypes of the female worms were found to be 17.7% linguiform, 76.6 % knobbed/button (p<0.05), and 5.7 % smooth type, demonstrating common features of H. contortus. The nucleotide sequences of the Internal Transcribed Spacer 1 (ITS-1) of 165 bp or ITS-2 plus of 256 bp were aligned, and it was found that the genotypes of male and female specimens of either sheep or goat origin were identical, with a 100 % match. The present isolates shared >95 % and >94 % homology with published sequences of ITS-1 and ITS-2 plus of H. contortus, respectively, with more nucleotide transitions than transversions in the aligned sequences. The reconstructed phylogram of either ITS-1 or ITS-2 plus revealed two major clades, one for H. contortus and another for other nematodes, with Haemonchus placei showing its proximity with the clade of H. contortus. The study established the role of morphological and molecular features in identifying and differentiating H. contortus parasite at the local level.

PREVALENCE OF Blastocystis sp. IN CATTLE, GOAT AND SHEEP REARED BY DIFFERENT FARM MANAGEMENT SYSTEMS IN PAHANG, MALAYSIA

Blastocystis sp. is a familiar parasite in the gastrointestinal tract causing infection in humans and animals. The purpose of this study is to evaluate the Blastocystis sp. prevalence in three sorts of livestock; cattle, goats, and sheep in Pahang, Malaysia, which are reared under two management systems; intensive and semi-intensive farm management system. About 92, 96, and 65 cattle, goat, and sheep fecal samples respectively were collected from different farms around Kuantan, Bera, and Pekan. The fecal samples were cultured in Jones’ medium supplemented with 10% heat-inactivated horse serum and incubated at 37 ºC for 2 weeks, then observed under light microscopy daily. The total prevalence of Blastocystis sp. was 29.34% in cattle (27/92), 29.16% in goats (28/96), and 43.07% in sheep (28/65). Supported the results of this study, Blastocystis sp. prevalence was higher in sheep and livestock reared by a semi-intensive farm management system (44.38%). However, further study could be done for Blastocystis sp. subtypes identification to determine its genetic diversity. Notwithstanding, this study has provided additional knowledge on the prevalence of each livestock reared in farms around Pahang that serve as important information in understanding host-parasite relationships, besides determining the best farm management system to be applied by farmers.

Helminth Infections in Cattle and Goats in Kanchanaburi, Thailand, with Focus on Strongyle Nematode Infections

Gastrointestinal helminths are major enteric parasites affecting the health of important livestock ruminants, such as cattle and goats. It is important to routinely survey these animals for helminth infections to allow effective management and control programs to be implemented. A cross-sectional helminth survey carried out in Kanchanaburi Province, Thailand, revealed the infection rate of gastrointestinal helminths in cattle (n = 157) and goats (n = 117) to be 35.7% and 88%, respectively, by microscopic fecal examination, and a 100% herd prevalence was observed in goats. Eggs of strongyle nematodes, Strongyloides spp., Trichuris spp., Capillaria spp., Paramphistomum spp., and Moniezia spp. were detected, with a relatively high rate of strongyle nematode infection in both cattle (28.7%) and goats (86.3%). Mixed infections were observed in 14.3% and 35.9% of egg-positive samples from cattle and goats, respectively. Risk factor analysis showed that dairy cattle were 5.1 times more likely to be infected with strongyles than meat cattle. In contrast, meat goats were 9.3 times more likely to be infected with strongyles than dairy goats. The inverse findings in cattle and goats are discussed. Female gender was associated with a higher risk of strongyle infection in goats. DNA sequencing and in-house semi-nested PCR with primers specific to a region in the internal transcribed spacer 2 (ITS2) were successfully used to identify strongyle genera in randomly selected egg-positive cattle (n = 24) and goat (n = 24) samples. Four strongyle genera, i.e., Cooperia spp., Haemonchus spp., Oesophagostomum spp., and Trichostrongylus spp. were identified by DNA sequencing. By semi-nested PCR, Cooperia spp. were detected as a major parasite of cattle (70.8%), whereas Haemonchus spp. were abundant in goats (100%). The majority of samples from cattle (58.3%) and goats (95.8%) were found to coinfect with at least two strongyle genera, suggesting that coinfection with multiple strongyle genera was more common than single infection in these animals.

Phylogenetic analysis of Trichostrongylus vitrinus isolates from southwest Iran

Background

Trichostrongylus is one of the most important zoonotic trichostrongylid nematodes, infecting mostly livestock. Data on its genetic characteristics are lacking in Iran.

Methods

We determined the phylogenetic relationships of Trichostrongylus species in three counties of Kohgiloyeh and Boyerahmad (K-B) province, southwest Iran. Small intestine and abomasum of 70 sheep and goats were investigated.

Results

A total of 35 isolates of Trichostrongylus worms were detected and all were genetically identified as Trichostrongylus vitrinus. Analysis of 321 bp of the internal transcribed spacer 2 (ITS2) of ribosomal DNA revealed 16 genotypes. All genotypes were single nucleotide polymorphisms, including some hypervariable points. All sequences were trimmed to 170 bp, compared with sequences on GenBank including short sequences from other endemic foci of Iran and other countries and all isolates were used to generate a maximum likelihood phylogenetic tree, which consisted of two clades A and B. Clade A included isolates from Iran, Russia, New Zealand, Australia and the UK; clade B only contained South African isolates. Most clade A isolates (north, southwest and west Iran, Russia, New Zealand, Australia and UK) were in a similar phylogenetic position. One subclade was detected in clade A (isolates from Southwest Iran, New Zealand and UK).

Conclusions

We hypothesize that drug resistant T. vitrinus may account for its exclusive detection in our samples. The high similarity of genotypes from Iran, New Zealand and UK may be due to their close political relationships during the colonial era. More research is needed to understand better the phylogeny of T. vitrinus and its relationship with drug resistance and human transmission.

Interaction between abomasal blood feeder Haemonchus contortus and intestinal mucosal browser Trichostrongylus colubriformis during co-infection in Boer goats

This study was conducted to investigate potential interactions between the abomasal blood feeder Haemonchus contortus and the intestinal mucosal browser Trichostrongylus colubriformis among deliberately infected Boer goats. Faecal and blood samples were collected twice a week for eight weeks from 25 parasite-naïve goats. Correlation analysis and multiple linear regression models were conducted to explore the association between phenotypic variables and variables taken at necropsy. Positive associations were identified between total FEC and log T. colubriformis number (r = 0.62, p < 0.05) as well as between IgA and peripheral eosinophil counts (r = 0.65, p < 0.05). A negative correlation was observed between T. colubriformis and log H. contortus number (r=-0.56, p < 0.05). Multiple linear regression models show that H. contortus and T. colubriformis interacted with each other. T. colubriformis appeared to contribute more significantly to the variation of FEC than H. contortus. Co-infection induced an IgA response which was only effective against T. colubriformis but not protective against H. contortus infection. This could be seen via significant associations of IgA with both nematode species but with the effect of IgA differing for H. contortus and T. colubriformis. In this study, H. contortus infection was not detrimental to the goats with no observed impact on PCV. This could be because the growth of T. colubriformis as represented by its length was associated with reduced number and composite burden of H. contortus during co-infection, or possibly due to low infection dosage. Improved understanding of the impact of H. contortus and T. colubriformis and their interaction from natural co-infection studies is beneficial for a better understanding of the goat-parasite interaction and its potential impacts on the health and productivity of animals.

Characterization of benzimidazole resistance in Haemonchus contortus: integration of phenotypic, genotypic and proteomic approaches

The field strain of Haemonchus contortus has a long history of anthelmintic resistance. To understand this phenomenon, the benzimidazole resistance profile was characterized from the Malaysian field-resistant strain by integrating phenotypic, genotypic and proteomic approaches. The faecal egg count reduction test (FECRT) demonstrated that benzimidazole resistance was at a critical level in the studied strain. The primary resistance mechanism was attributed to F200Y mutation in the isotype 1 β-tubulin gene as revealed by AS-PCR and direct sequencing. Furthermore, the protein response of the resistant strain towards benzimidazole (i.e., albendazole) treatment was investigated via two-dimensional difference gel electrophoresis (2D-DIGE) and tandem liquid chromatography-mass spectrometry (LC-MS/MS). These investigations illustrated an up-regulation of antioxidant (i.e., ATP-binding region and heat-shock protein 90, superoxide dismutase) and metabolic (i.e., glutamate dehydrogenase) enzymes and down-regulation of glutathione S-transferase, malate dehydrogenase, and other structural and cytoskeletal proteins (i.e., actin, troponin T). Findings from this study are pivotal in updating the current knowledge on anthelmintic resistance and providing new insights into the defence mechanisms of resistant nematodes towards drug treatment.

Molecular detection of porcine Enterocytozoon bieneusi infection in Peninsular Malaysia and epidemiological risk factors associated with potentially zoonotic genotypes

Enterocytozoon bieneusi is an emerging opportunistic pathogen infecting humans, and both domestic and wild pigs are known to harbour zoonotic genotypes. There remains a paucity of information on the prevalence and epidemiology of this enteropathogen in Southeast Asia. The present study was undertaken to determine the molecular prevalence and risk factors associated with E. bieneusi infection among commercially farmed pigs in Malaysia. Faecal samples were collected from 450 pigs from 15 different farms and subjected to nested PCR amplification of the ribosomal internal transcribed spacer (ITS) gene of E. bieneusi. Phylogenetic analysis involved 28 nucleotide sequences of the ITS region of E. bieneusi. An interviewer-administered questionnaire provided information on the animal hosts, farm management systems and environmental factors and was statistically analysed to determine the risk factors for infection. The prevalence of E. bieneusi infection was relatively high (40.7%). The highest prevalence (51.3%) was recorded among the piglets, while the adults showed the lowest level of infection (31.3%). Multivariate analysis indicated that age of the pigs, distance of the farm from human settlement and farm management system were significant risk factors of infection. Three genotypes (EbpA, EbpC and Henan-III) detected among the pigs are potentially zoonotic. The high prevalence of E. bieneusi among locally reared pigs, the presence of zoonotic genotypes and the spatial distribution of pig farms and human settlements warrant further investigation on the possibility of zoonotic transmission.

Kinetics of IgA and eosinophils following a low-dose, predominantly Haemonchus contortus infection of Boer goats

AIMS

Most breeds of goat are more susceptible to nematode infection than sheep, and this appears to be a consequence of less effective immune responses. Several papers have considered the effectiveness of eosinophils and immunoglobulin A (IgA) in goats but differences in the induction of responses have not been studied in the same detail. The aim of this study was to look at the induction of eosinophil and IgA responses in Boer goats reared indoors under intensive conditions.

METHODS AND RESULTS

The goats were experimentally infected with a low dose of 2400 Haemonchus contortus, Trichostrongylus spp. and Oesophagostomum spp. at a 6:1:1 ratio. Faecal egg counts (FEC), packed cell volume (PCV), IgA activity against third-stage larvae and peripheral eosinophilia were measured twice a week for eight weeks. The infection generated an IgA response but did not significantly increase peripheral eosinophilia in the 25 infected kids compared with the 4 control animals. FEC was not associated with IgA activity or eosinophilia.

CONCLUSION

A detailed analysis of IgA and eosinophil responses to deliberate nematode infection in Boer goats showed that there was an increase in nematode-specific IgA activity but no detectable eosinophil response. In addition, there was no association between increased IgA activity or eosinophilia with egg counts and worm burdens. These suggest that IgA and eosinophils do not act to control nematode infection in goats.

Molecular detection of Trichostrongylus species through PCR followed by high resolution melt analysis of ITS-2 rDNA sequences

Polymerase chain reaction followed by high resolution melting (PCR-HRM) analysis is a simple, rapid and accurate method for molecular detection of various nematode species. The objective of the present study was, for the first time, to develop a PCR-HRM assay for the detection of various animal Trichostrongylus spp. A pair of primers targeting the ITS-2 rDNA region of the Trichostrongylus spp. was designed for the development of the HRM assay. DNA samples were extracted from 30 adult worms of Trichostrongylus spp., the ITS-2-rDNA region was amplified using PCR, and the resultant products were sequenced and characterized. Afterwards, the PCR-HRM analysis was conducted to detect and discriminate Trichostrongylus spp. Molecular sequence analysis revealed that 24, 4, and 1 of the samples were T. colubriformis, T. vitrinus and T. capricola, respectively. Results from PCR-HRM indicated that complete agreement was relatively found between speciation by HRM analysis and DNA sequencing for the detection of Trichostrongylus species. The PCR-HRM analysis method developed in the present study is fast and low-cost; the method can be comparable with other molecular detection techniques, representing a reliable tool for the identification of various species within the Trichostrongylus genus.

Infection dynamics of gastrointestinal helminths in sympatric non-human primates, livestock and wild ruminants in Kenya

BACKGROUND

Gastrointestinal parasites are neglected infections, yet they cause significant burden to animal and human health globally. To date, most studies of gastrointestinal parasites focus on host-parasite systems that involve either a single parasite or a host species. However, when hosts share habitat and resources, they may also cross-transmit generalist gastrointestinal parasites. Here we explore multi-host-parasite interactions in a single ecosystem to understand the infection patterns, especially those linked to livestock-wildlife interfaces and zoonotic risk.

METHODS

We used both coprological methods (flotation and sedimentation; N = 1,138 fecal samples) and molecular identification techniques (rDNA and mtDNA; N = 18 larvae) to identify gastrointestinal parasites in nine sympatric host species (cattle, sheep, goats, wildebeest, Grant's gazelles, Thomson's gazelles, impala, vervet monkeys and baboons) in the Amboseli ecosystem, Kenya.

RESULTS

We found that the host community harbored a diverse community of gastrointestinal helminths, including 22 species and/or morphotypes that were heterogeneously distributed across the hosts. Six zoonotic gastrointestinal helminths were identified: Trichuris spp., Trichostrongylus colubriformis, Enterobius spp. Oesophagostomum bifurcum, Strongyloides stercoralis and Strongyloides fuelleborni. The dominant parasite was Trichuris spp, whose ova occurred in two morphological types. Baboons were co-infected with Strongyloides fuelleborni and S. stercoralis.

CONCLUSIONS

We found that the interface zone shared by wild ungulates, livestock and non-human primates is rich in diversity of gastrointestinal helminths, of which some are extensively shared across the host species. Closely related host species were most likely to be infected by the same parasite species. Several parasites showed genetic sub-structuring according to either geography or host species. Of significance and contrary to expectation, we found that livestock had a higher parasite richness than wild bovids, which is a health risk for both conservation and livestock production. The zoonotic parasites are of public health risk, especially to pastoralist communities living in areas contiguous to wildlife areas. These results expand information on the epidemiology of these parasites and highlights potential zoonotic risk in East African savanna habitats.

Molecular detection and epidemiological risk factors associated with Cryptosporidium infection among cattle in Peninsular Malaysia

Enteric protozoa infection among cattle may pose a threat to productivity and survival leading to negative impacts on the livestock industry. A number of these pathogens are also known to be zoonotic and are of public health concern. Despite the importance of these enteric protozoa to both animal and human health, there remains a paucity of published information on the epidemiological risk factors that may be associated with bovine cryptosporidiosis in Southeast Asia. The present study was undertaken to determine the molecular prevalence and associated risk factors for Cryptosporidium infection among beef and dairy cattle in Peninsular Malaysia. Faecal samples were collected from 824 cattle in 39 farms (526 beef and 298 dairy) situated in 33 locations throughout the country, and subjected to PCR detection for Cryptosporidium using primers targeting the 18S SSUrRNA gene. Epidemiological variables including host, environment and management factors were subjected to univariate and multivariate logistic regression analyses to determine the potential risk factors for infection. The prevalence of Cryptosporidium among the cattle was 12.5%, with significant difference in the infection rate among the various breeds. There was no significant effect of gender, and both the beef and dairy cattle were at similar odds for infection. The younger cattle had a significantly higher infection rate compared to the older animals. Multivariate analysis revealed that deworming practice, distance to human settlement, geographical location (zone) and farm management system were significant risk factors associated with Cryptosporidium infection. The cattle that were reared on farms located in the northeast of the country, closest (≤200 m) to human settlements, reared extensively, and dewormed every four months were at highest risk of infection. The present study constitutes the first attempt to analyze the multivariable epidemiological risk factors involved in bovine cryptosporidiosis in Malaysia and in Southeast Asia. It is envisaged that the data obtained will facilitate better control and prevention measures for Cryptosporidium infection among cattle in the region. Due to the potential zoonotic nature of the infection, serious steps should be instituted for animal treatment and biohazard waste management on local cattle farms.

A multiplex restriction enzyme-PCR for unequivocal identification and differentiation of Trichostrongylus species in human samples

Trichostrongylus species remain one of the major health challenges in the tropical and summer rainfall regions worldwide. Identification of strongylid species diagnostic methods is vital for obtaining a deep understanding of the epidemiology, population biology, anthelmintic treatment efficacy, and drug resistance in order to design effective parasite control strategies. We evaluated a multiplex RE-PCR for the diagnosis of key Trichostrongylus spp. Genomic DNA amplification of Trichostrongylus colubriformis, Trichostrongylus axei and Trichostrongylus vitrinus was achieved as standard sample using specific primers located in the second internal transcribed spacer (ITSII) of nuclear ribosomal DNA (rDNA). The mentioned method was based on isolation of Trichostrongylus ova from human fecal samples using Willis method, the extraction of ova genomic DNA samples, followed by rDNA ITSII PCR and one-step multiplex RE-PCR using three restriction enzymes of HinfI, DraI, and MseI. The multiplex RE-PCR technique provides a useful tool for discriminating all Trichostrongylus spp., being useful for diagnostic, epidemiological, ecological studies, and control programs. This method is rapid, especially when numerous restriction enzymes are required for species differentiation or identification.

Molecular Phylogenetics of Trichostrongylus Species (Nematoda: Trichostrongylidae) from Humans of Mazandaran Province, Iran

The present study was performed to analyze molecularly the phylogenetic positions of human-infecting Trichostrongylus species in Mazandaran Province, Iran, which is an endemic area for trichostrongyliasis. DNA from 7 Trichostrongylus infected stool samples were extracted by using in-house (IH) method. PCR amplification of ITS2-rDNA region was performed, and products were sequenced. Phylogenetic analysis of the nucleotide sequence data was performed using MEGA 5.0 software. Six out of 7 isolates had high similarity with Trichostrongylus colubriformis, while the other one showed high homology with Trichostrongylus axei registered in GenBank reference sequences. Intra-specific variations within isolates of T. colubriformis and T. axei amounted to 0–1.8% and 0–0.6%, respectively. Trichostrongylus species obtained in the present study were in a cluster with the relevant reference sequences from previous studies. BLAST analysis indicated that there was 100% homology among all 6 ITS2 sequences of T. colubriformis in the present study and most previously registered sequences of T. colubriformis from human, sheep, and goat isolates from Iran and also human isolates from Laos, Thailand, and France. The ITS2 sequence of T. axei exhibited 99.4% homology with the human isolate of T. axei from Thailand, sheep isolates from New Zealand and Iran, and cattle isolate from USA.

Leucocyte-derived extracellular trap formation significantly contributes to Haemonchus contortus larval entrapment

BACKGROUND

Polymorphonuclear neutrophil (PMN) and eosinophil extracellular trap (ETs) formation has recently been described as an important host effector mechanism against invading pathogens. So far, scarce evidence on metazoan-triggered ET formation has been published. We here describe for the first time Haemonchus contortus-triggered ETs being released by bovine PMN and ovine eosinophils in response to ensheathed and exsheathed third stage larvae (L3).

METHODS

The visualization of ETs was achieved by SEM analysis. The identification of classical ETs components was performed via fluorescence microscopy analysis. The effect of larval exsheathment and parasite integrity on ET formation was evaluated via Pico Green®- fluorescence intensities. ETs formation under acidic conditions was assessed by using media of different pH ranges. Parasite entrapment was evaluated microscopically after co-culture of PMN and L3. ET inhibition experiments were performed using inhibitors against NADPH oxidase, NE and MPO. Eosinophil-derived ETs were estimated via fluorescence microscopy analysis.

RESULTS

L3 significantly induced PMN-mediated ETs and significant parasite entrapment through ETs structures was rapidly observed after 60 min of PMN and L3 co-culture. Co-localization studies of PMN-derived extracellular DNA with histones (H3), neutrophil elastase (NE) and myeloperoxidase (MPO) in parasite-entrapping structures confirmed the classical characteristics of ETs. Haemonchus contortus-triggered ETs were significantly diminished by NADPH oxidase-, NE- and MPO-inhibition. Interestingly, different forms of ETs, i.e. aggregated (aggETs), spread (sprETs) and diffused (diffETs) ETs, were induced by L3. AggETs and sprETs firmly ensnared larvae in a time dependent manner. Significantly stronger aggETs reactions were detected upon exposure of PMN to ensheathed larvae than to exsheathed ones. Low pH conditions as are present in the abomasum did not block ETosis and led to a moderate decrease of ETs. Eosinophil-ETs were identified extruding DNA via fluorescence staining.

CONCLUSION

We postulate that ETs may limit the establishment of H. contortus within the definitive host by immobilizing the larvae and hampering them from migrating into the site of infection. Consequently, H. contortus-mediated ET formation might have an impact on the outcome of the disease. Finally, besides PMN-triggered ETs, we here present first indications of ETs being released by eosinophils upon H. contortus L3 exposure.