Parasitic Nematode Species Research Articles

Description of Pudica wandiquei n. sp. (Heligmonellidae: Pudicinae), a nematode found infecting Proechimys simonsi (Rodentia: Echimyidae) in the Brazilian Amazon.

A new species of nematode parasite of the subfamily Pudicinae (Heligmosomoidea: Heligmonellidae) is described from the small intestine of Proechimys simonsi (Rodentia: Echimyidae) from the locality of Nova Cintra in the municpality of Rodrigues Alves, Acre state, Brazil. The genus Pudica includes 15 species parasites of Neotropical rodents of the families Caviidae, Ctenomyidae, Dasyproctidae, Echimyidae, Erethizontidae, and Myocastoridae. Four species of this nematode were found parasitizing three different species rodents of the genus Proechimys in the Amazon biome. Pudica wandiquei n. sp. can be differentiated from all other Pudica species by the distance between the ends of rays 6 and 8 and the 1-3-1 pattern of the caudal bursa in both lobes.

Reação de genótipos de feijoeiro a nematoides de plantas

ABSTRACT Among the efficient strategies to manage plant parasitic nematodes, the use of resistant cultivars stands out for being frequently the easiest and least expensive approach that can be adopted by farmers. However, for the common bean, in Brazil, few sources of resistance have been identified so far. This study aimed to assess the reaction of 81 common bean genotypes to the most abundant and harmful plant parasitic nematode species in Brazilian crop fields. Genotypes resistant to all tested nematodes were observed: 7 to Heterodera glycines, 2 to Pratylenchus brachyurus, 15 to Meloidogyne incognita and 8 to M. javanica.

Parasitic Nematodes of Plant Persimmon (Diospyros Kaki, l.) Rhizosphere in District Swat, Kp Pakistan

Purpose: Different species of plant parasitic nematodes of persimmon (Diospyros kaki, L.) were identified from various localities of District Swat KPK Pakistan namely Chail, Madyan, Piya, Jare, Chikrai, Thesil, Fateh pur, Baghdheri, Naway kalay, Shin, Pirpatay, Sambat and Gurra. Methods: Soil samples were collected from the bases of persimmon trees along with rhizospheres that show stunted growth. The collected samples were then processed by using modified Bearmann funnel technique. Nematode specimens isolated in cavity block were killed by heat and treated with TAF (Triethylamine formaldehyde) solution. Findings and Practical implication: After 24 hours, the specimens were transferred to 1.25 % glycerin with trace amount of picric acid for staining of nematodes. Nine different species of nematodes were reported from these localities were Tylenchus spp, Psilenchus spp, Meloidogyne larvae, Aphelenchus spp, Tylenchus juveniles, Filenchus spp, Pratylenchus spp, Helicotylenchus pseudorobustus and Helicotylenchus dihystera. Helicotylenchus species were more common in the collected samples. Conclusion: It is concluded from analysis of soil samples that plant parasitic nematodes associated with persimmon cause economic loss in district swat. Persimmon plants show stunted and retarded growth in soil which has high nematode population density. Keywords: Nematodes, Persimmon, Swat, Diospyros kaki, Triethylamine formaldehyde.

A High Prevalence of Cardiopulmonary Worms Detected in the Iberian Wolf (Canis lupus): A Threat for Wild and Domestic Canids.

Simple SummaryThe Iberian wolf (Canis lupus signatus) is a recognized reservoir of some zoonotic parasites that cause diseases transmissible to domestic animals and/or humans. The objective of this study was to determine the diversity of species of cardiopulmonary nematode parasites that affect wolves in northwestern Spain, and to estimate their prevalence and the relationship between these parasites and various epidemiological variables. The cardiopulmonary systems of 57 wolves from Galicia were examined using dissection and cup sedimentation techniques, and the collected worms were then morphologically identified. The overall prevalence of infection by cardiopulmonary nematodes was 24.5%, and the parasite species identified were Angiostrongylus vasorum (19.3%), Crenosoma vulpis (7%) and Eucoleus aerophilus (3.5%). The latter is of zoonotic interest. A significant relationship was found between age and C. vulpis infection, which was only found in animals under one year of age. Our findings indicate that the Iberian wolf could play an important role in maintaining cardiopulmonary parasites in the wild, and they highlight a need to identify potential risks for veterinary and public health.Cardiopulmonary nematodes are highly pathogenic parasites affecting domestic and wild canids. As the result of conservation programs, the Iberian wolf (Canis lupus signatus) population has recently expanded, and its distribution range covers lands from where it had long disappeared. However, the exact epidemiological role of the wolf in the life cycle of zoonotic parasites causing diseases transmissible to pets and/or humans is largely unknown. This study sought to determine the diversity of cardiopulmonary nematode parasite species that affect wolves inhabiting northwestern areas of the Iberian Peninsula, and to estimate their prevalence and the relationship between these parasites and several epidemiological variables. For this purpose, we examined the cardiopulmonary systems of 57 wolves from Galicia (from the provinces A Coruña n = 15, Lugo n = 21, Ourense n =15 and Pontevedra n = 6) using techniques of dissection and cup sedimentation. Collected worms were then identified under a light microscope according to their morphological features. Three species of nematodes were detected: Angiostrongylus vasorum (the “French-heartworm”), Crenosoma vulpis and Eucoleus aerophilus, the latter being of zoonotic interest. The prevalence was 24.5% (14/57; 95% CI 13.3–35.6%) overall, 19.3% for A. vasorum (11/57; 95% CI 8.8–29.2%), 7% for C. vulpis (4/57; 95% CI 0.4–13.6%) and 3.5% for E. aerophilus (2/57; CI −1.1–9.1%). A significant relationship (p = 0.002) was found between age and the presence of C. vulpis, which was only found in juvenile animals. Furthermore, a higher prevalence of A. vasorum and/or C. vulpis was observed in wolves with a lower body condition score (40% and 20%, respectively), though the difference was not significant (p = 0.221 and p = 0.444, respectively). Our findings indicate a high “French-heartworm” and lungworm burden in the wolf population of northern Spain, and they identify a need for studies designed to elucidate the epidemiological role played by the Iberian wolf and to identify possible risks for veterinary and public health.

Interactions of Caenorhabditis elegans β-tubulins with the microtubule inhibitor and anthelmintic drug albendazole.

Parasitic nematodes are major human and agricultural pests, and benzimidazoles are amongst the most important broad-spectrum anthelmintic drug class used for their control. Benzimidazole resistance is now widespread in many species of parasitic nematodes in livestock globally and an emerging concern for the sustainable control of human soil-transmitted helminths. β-tubulin is the major benzimidazole target, although other genes may influence resistance. Among the 6 Caenorhabditis elegans β-tubulin genes, loss of ben-1 causes resistance without other apparent defects. Here, we explored the genetics of C. elegans β-tubulin genes in relation to the response to the benzimidazole derivative albendazole. The most highly expressed β-tubulin isotypes, encoded by tbb-1 and tbb-2, were known to be redundant with each other for viability, and their products are predicted not to bind benzimidazoles. We found that tbb-2 mutants, and to a lesser extent tbb-1 mutants, were hypersensitive to albendazole. The double mutant tbb-2 ben-1 is uncoordinated and short, resembling the wild type exposed to albendazole, but the tbb-1 ben-1 double mutant did not show the same phenotypes. These results suggest that tbb-2 is a modifier of albendazole sensitivity. To better understand how BEN-1 mutates to cause benzimidazole resistance, we isolated mutants resistant to albendazole and found that 15 of 16 mutations occurred in the ben-1 coding region. Mutations ranged from likely nulls to hypomorphs, and several corresponded to residues that cause resistance in other organisms. Null alleles of ben-1 are albendazole-resistant and BEN-1 shows high sequence identity with tubulins from other organisms, suggesting that many amino acid changes could cause resistance. However, our results suggest that missense mutations conferring resistance are not evenly distributed across all possible conserved sites. Independent of their roles in benzimidazole resistance, tbb-1 and tbb-2 may have specialized functions as null mutants of tbb-1 or tbb-2 were cold or heat sensitive, respectively.

Anisakid Nematodes and Potential Risk of Human Anisakiasis through the Consumption of Hake, Merluccius spp., Sold Fresh in Spanish Supermarkets

Nematode parasite species belonging to the Anisakis simplex complex are the most important cause of human anisakiasis through the consumption of (mainly) undercooked, previously not frozen, or conveniently treated fish. In Spain, the consumption of hake has been recognized as an important source of this parasitosis. With the aim of shedding light on the risk factors that can influence the potential risk of human anisakiasis in Spain through the consumption of fresh hake sold by nationwide supermarket chains, a total of 536 small hake specimens belonging to the species Merluccius bilinearis caught off the Northeast American coasts and Merluccius merluccius caught in the Northeast Atlantic and Mediterranean waters was analysed. Anisakids morphologically identified as Anisakis type I were found as the most prevalent and the most abundant species and were considered the main potential cause of human anisakiasis. Intrinsic and extrinsic factors concerning the hake, such as its origin and season of capture, its size, as well as the days passed between its capture and consumption, should be taken into account to avoid this human parasitosis. It is essential that consumers have access to fish label information which should include, as regulated by the European Commission, traceability data.

Opening a can of lungworms: Molecular characterization of Dictyocaulus (Nematoda: Dictyocaulidae) infecting North American bison (Bison bison).

Dictyocaulus is a globally distributed genus of lungworms of domestic and wild ungulates. Dictyocaulus adults inhabit the bronchi, frequently causing subclinical and clinical disease, and that impacts animal health and production. North American bison (Bison bison) and cattle (Bos taurus) share various parasitic nematode species, particularly in areas where co-grazing occurs. The current assumption is that North American bison share the lungworm D. viviparus with cattle, but this has not been confirmed on a molecular basis. The aim of this study was to molecularly characterize Dictyocaulus lungworm isolates from North American plains bison (Bison bison bison). Fecal samples were collected from 5 wild conservation bison herds located in Iowa, North Dakota, Oklahoma, Colorado, and Montana in 2019 and 2020, and from ranched and feedlot bison from 2 herds in Oklahoma and Texas. First-stage lungworm larvae (L1) were isolated via Baermann technique. Genomic DNA was extracted from L1s of up to 3 samples per herd and followed by PCR and sequencing targeting the internal transcribed spacer 2 (ITS2) region of the nuclear ribosomal DNA and the partial cytochrome oxidase c subunit 1 (cox1) of mitochondrial DNA. Phylogenetic analyses were performed in MEGA X 10.1. Sequences of North American plains bison Dictyocaulus belong to a single, uncharacterized species, clustering in well-supported clades (100% and 100% bootstrap support for ITS2 and cox1, respectively), differing from D. viviparus of cattle in North America and Europe, and European bison (Bison bonasus). Our results contradict previous assumptions regarding parasite identity, highlighting the need for characterization of this species through morphological and molecular methods, elucidating its biology and host range, and potential impact on host health. Further investigation into the biodiversity of Dictyocaulus species infecting bovids and cervids in North America is warranted.

First application of two distinguishment techniques: Using Linear Discriminate Function method and Artificial Neural Networks approach according to the ovary types for some plant parasitic nematodes

In this study mono and dual ovaries, which belonged to female individuals of different plant parasitic nematode species that were obtained from the quince (Cydonia oblonga Mill.) (Rosales: Rosaceae) cultivated areas in Sakarya Province (Turkey), were classified. The total number of 109 and 121 female nematodes, which were taken from the soil, were used in 2016, July and 2017, July, respectively. Overall body length (L), spear length (Stylet) and tail/distance from vulva to anus (T/VA) parameters belonged to these nematodes were measured and examined. The mono and dual ovary groups were distinguished by using the Linear Discriminate Function (LDF) method (Fisher’s method) and Artificial Neural Networks (ANNs) approach taking correlation between those parameters into consideration. The pair of parameters L and (T/VA) had higher accuracy percentage (as 97% for LDF method and 100% for ANNs approach) than the pair of parameters L and Stylet (as 91% for LDF method and 97% for ANNs approach) for the classification using 2017, July data set. The second approach was more successful than the first method. This research is the first study that was used these method and approach together at the nematology study area in Turkey and the World. The taxonomical studies may be improved using different statistical methods and artificial neural networks approaches together at the nematology.

Nematode Orthologs of Macrophage Migration Inhibitory Factor (MIF) as Modulators of the Host Immune Response and Potential Therapeutic Targets.

One of the adaptations of nematodes, which allows long-term survival in the host, is the production of proteins with immunomodulatory properties. The parasites secrete numerous homologs of human immune mediators, such as macrophage migration inhibitory factor (MIF), which is a substantial regulator of the inflammatory immune response. Homologs of mammalian MIF have been recognized in many species of nematode parasites, but their role has not been fully understood. The application of molecular biology and genetic engineering methods, including the production of recombinant proteins, has enabled better characterization of their structure and properties. This review provides insight into the current state of knowledge on MIF homologs produced by nematodes, as well as their structure, enzymatic activity, tissue expression pattern, impact on the host immune system, and potential use in the treatment of parasitic, inflammatory, and autoimmune diseases.

Calves gastrointestinal nematodes and Eimeria prevalence and associated risk factors in dairy farms, southern Ethiopia

Dairy production is an important component of livestock farming in Ethiopia. Nevertheless, the productivity of the sector has been impacted negatively by the morbidity and mortality of replacement animals. A Cross-sectional study was, therefore, aimed at estimating the prevalence of Nematode and Eimeria infection in calves in Hawassa, Shashemene and Arsi Negelle, southern Ethiopia. To this end, a flotation technique was used to recover Nematode egg and Eimeria oocyst from rectally collected faeces. The overall prevalence of gastrointestinal parasitic infection, Nematode and Eimeria species collectively, was 43.9% (95% CI=38.6-49.4). The estimated proportion of Nematode, Eimeria and mixed infection was 35.8%, 21.5% and 13.3%, respectively. Among the potential factors considered faecal consistency, age and study area were found to increase recovery of Nematode egg and Eimeria oocyst in faeces (p< 0.05). Area wise, the prevalence has been noted to be higher at Arsi Negelle followed by Hawassa and Shashemene (p< 0.05). Besides, younger and diarrheic calves were found more infected by Nematode and Eimeria species than their adult and non-diarrheic counterpart. Based on their morphological appearance, Strongyle type (20.3%), Trichuris (4.2%) and Ascaris (16.3%) eggs, Eimeria oocysts (21.5%) were observed. In the light of this finding, the authors would like to advise the need for strategic intervention.

Bacillus thuringiensis toxins with nematocidal activity against the pinewood nematode Bursaphelenchus xylophilus

The pine wilt disease is caused by the pinewood nematode Bursaphelenchus xylophilus and it results in serious ecological and economic losses. Therefore, effective prevention and control methods for the pinewood nematode are urgently required. Bacillus thuringiensis (Bt), a widely used microbial insecticide, produces toxins that are toxic to several species of parasitic nematodes, however, its effects on B. xylophilus have not been determined. In this study, Cry5Ba3, App6Aa2, Cry12Aa1, Cry13Aa1, Cry14Aa1, Cry21Aa3, Cry21Fa1, Xpp55Aa1, and Cyt8Aa1 toxins’ nematocidal activity against B. xylophilus was evaluated, six toxins with high toxicity were identified: App6Aa2 (LC50 = 49.71 μg/mL), Cry13Aa1 (LC50 = 53.17 μg/mL), Cry12Aa1 (LC50 = 58.88 μg/mL), Cry5Ba3 (LC50 = 63.99 μg/mL), Xpp55Aa1 (LC50 = 65.14 μg/mL), and Cyt8Aa1 (LC50 = 96.50 μg/mL). The six toxins caused shrinkage and thinning of the intestinal cells, contraction of the intestine from the body wall, vacuolization, and degenerated appearance of the pinewood nematodes. The results of this study provide basic information to study the action mechanism of nematocidal toxins on the pinewood nematode and direction for the use of nematocidal toxins in the biological control of B. xylophilus.

Molecular analysis of nematode-responsive defence genes CRF1, WRKY45, and PR7 in Solanum lycopersicum tissues during the infection of plant-parasitic nematode species of the genus Meloidogyne.

Several pathogens, including nematodes, have severe effects on plant development and growth, and immense populations of parasitic nematodes may cause plant death and crop loss. Obligate plant-parasitic nematodes and root-knot nematodes belonging to the genus Meloidogyne are significant parasites in crops. During nematode infection, damage-associated molecular patterns play a role in the activation of plant defence responses to pathogens. Several genes are involved in Meloidogyne parasitism. However, the expression of nematode-responsive genes CRF1, WRKY45, and PR7 during infection with different parasitic nematode species is not well understood. Therefore, this study aimed to reveal plant responses to differential gene expression of nematode-responsive genes in tomato plants, and their relationship to nematode reproduction and comparative phylogeny. Molecular methods for gene expression, greenhouse work for nematode reproduction, and phylogenetic analysis were used to determine nematode-plant interactions. The results revealed that differential gene expression of CRF1, WRKY45, and PR7 depended on the nematode species. The relative CRF1 gene expression reached its highest level at 3 dpi, following nematode infection. In conclusion, plant defense responses disturbed the expression of nematode-responsive genes, and the differential expression of nematode-responsive genes was affected by nematode species and nematode parasitism.

Ecological and Morphological Differentiation Among COI Haplotype Groups in the Plant Parasitic Nematode Species Mesocriconema Xenoplax.

DNA barcoding with the mitochondrial COI gene reveals distinct haplotype subgroups within the monophyletic and parthenogenetic nematode species, Mesocriconema xenoplax. Biological attributes of these haplotype groups (HG) have not been explored. An analysis of M. xenoplax from 40 North American sites representing both native plant communities and agroecosystems was conducted to identify possible subgroup associations with ecological, physiological, or geographic factors. A dataset of 132 M. xenoplax specimens was used to generate sequences of a 712 bp region of the cytochrome oxidase subunit I gene. Maximum-likelihood and Bayesian phylogenies recognized seven COI HG (≥99/0.99 posterior probability/bootstrap value). Species delimitation metrics largely supported the genetic integrity of the HG. Discriminant function analysis of HG morphological traits identified stylet length, total body length, and stylet knob width as the strongest distinguishing features among the seven groups, with stylet length as the strongest single distinguishing morphological feature. Multivariate analysis identified land cover, ecoregion, and maximum temperature as predictors of 53.6% of the total variation (P = 0.001). Within land cover, HG categorized under “herbaceous,” “woody wetlands,” and “deciduous forest” were distinct in DAPC and RDA analyses and were significantly different (analysis of molecular variance P = 0.001). These results provide empirical evidence for molecular, morphological, and ecological differentiation associated with HG within the monophyletic clade that represents the species Mesocriconema xenoplax.

The Caenorhabditis elegans DEG-3/DES-2 Channel Is a Betaine-Gated Receptor Insensitive to Monepantel.

Natural plant compounds, such as betaine, are described to have nematocidal properties. Betaine also acts as a neurotransmitter in the free-living model nematode Caenorhabditis elegans, where it is required for normal motility. Worm motility is mediated by nicotinic acetylcholine receptors (nAChRs), including subunits from the nematode-specific DEG-3 group. Not all types of nAChRs in this group are associated with motility, and one of these is the DEG-3/DES-2 channel from C. elegans, which is involved in nociception and possibly chemotaxis. Interestingly, the activity of DEG-3/DES-2 channel from the parasitic nematode of ruminants, Haemonchus contortus, is modulated by monepantel and its sulfone metabolite, which belong to the amino-acetonitrile derivative anthelmintic drug class. Here, our aim was to advance the pharmacological knowledge of the DEG-3/DES-2 channel from C. elegans by functionally expressing the DEG-3/DES-2 channel in Xenopus laevis oocytes and using two-electrode voltage-clamp electrophysiology. We found that the DEG-3/DES-2 channel was more sensitive to betaine than ACh and choline, but insensitive to monepantel and monepantel sulfone when used as direct agonists and as allosteric modulators in co-application with betaine. These findings provide important insight into the pharmacology of DEG-3/DES-2 from C. elegans and highlight the pharmacological differences between non-parasitic and parasitic nematode species.

Molecular and morphological characterization of stunt nematodes of wheat, maize, and rice in the savannahs of northern Nigeria

Stunt nematodes (Tylenchorhynchus spp.) are obligate migratory root ecto-parasitic nematodes found in the fields of many cultivated crops. These nematodes, with phyto-sanitary potential, are frequently ignored or misdiagnosed as pests, and this may pose a threat to food security. The accuracy of its identification based on a morphological approach has been challenged recently, due to the overlapping of the morphological and morphometric characters of the species. Consequently, the objective of this study is to identify and characterize stunt nematodes present in 54 fields cultivated with cereal crops (wheat, maize and rice) in the savannahs of northern Nigeria, using integrative taxonomy and molecular approaches. The molecular and morphological studies identified and confirmed the presence of T. annulatus as the occurring specie in the savannahs of northern Nigeria. The phylogenetic analysis was carried out using the internal transcribed spacer (ITS) and 28S genes of ribosomal DNA further confirmed the presence of T. annulatus. The first molecular characterization and sequences of the ITS and 28S rDNA gene for T. annulatus from Nigeria were provided by this research. Also, according to our literature search, this is the first report on T. annulatus in wheat, maize and rice in the savannahs of northern Nigeria. Further study to test the pathogenicity of the parasitic nematode species found in this survey is recommended for the prioritization and development of efficient management strategies.

Распространение дирофилярий (Spirurida, Onchocercidae) в природных популяциях малярийных комаров (Diptera, Culicidae) Томского Приобья

Dirofilariasis is a dangerous transmissible disease of carnivores and humans caused by two species of parasitic nematodes - Dirofilaria repens Railliet et Henry and D. immitis Leidy. The intermediate hosts of Dirofilariae are blood-sucking mosquitoes. Both species are typical of the mild climate of southern Europe, but in recent decades the parasites have spread to the north and northeast due to the global climate change. They have been registered in Western Siberia since 1989, and diro-filariasis cases in both animals and humans cause concern. To assess prospects for the spread of dirofilariasis and develop strategies to combat this disease, one has to determine the main mosquito vectors. Malaria mosquitos are the significant dirofilaria vectors in Europe, but there is a shortage of information on potential dirofilariasis vectors in Siberia. This paper is meant to estimate how extensive the invasion of different species of the malaria mosquitos D. repens and D. immitis is in the territory of Tomsk Region due to the global climate change. 64 samples of mosquitos from 36 localities of Tomsk Region were taken during the summer seasons of 2018 to 2020. Mosquitos were caught in stables, dissected to determine invasion via light microscopy. The species of malaria mosquitos and dirofilariae were identified through an ITS2 PCR-RFLP analysis (Artemov et al., 2021) and COI site-specific PCR (Rishniw et al., 1998), respectively. In total, the authors analyzed 7,591 female malaria mosquitos and 233 female non-malaria mosquitos, where 159 and 1 of them were infected with dirofilariae, respectively. They registered invasion in 44 samples from 21 localities, including the northernmost one - Strezhevoy town (60°44N, see Figure 1). Dirofilariasis is a common helminthiasis in Tomsk Region. The average invasion extensiveness is 2.1+0.2% in the region. In the natural populations of malaria mosquitos on the right bank of the River Ob, the invasion extensiveness is 3.7 times higher vs. the left bank of the Ob, despite the high transport accessibility of this bank (see Figure 2). Invasion extensiveness decreases from the south to the north, but the local conditions might disrupt this trend (see Table 3). Three species of malaria mosquitos - Anopheles daciae, An. messeae and An. beklemishevi (but not An. claviger) - are dirofilariasis vectors in Tomsk Region (see Table 1). South of 57° N, only D. repens and one mixed invasion case were found in An. daciae being the dominant species in this area. However, all the three species mainly invaded with D. repens were detected as vectors north of 57° N. One case of An. messeae invasion with the nematode D. immitis and mixed invasions of An. daciae and An. beklemishevi were found in Kolpashevo agglomeration. All the invasions with D. immitis (including mixed ones) were observed on the right bank of the Ob (see Table 2). The extensiveness of An. messeae and An. daciae invasion were significantly higher vs. An. beklemishevi, despite its domination north of 57° N. The northernmost location where an infective female of An. beklemishevi invaded with D. repens was found is Bolshaya Griva village at 59° N. Approximately 6.5% of the infected mosquitos had superinvasion - re-invasion with dirofilariae (see Figure 3). Thus, malaria mosquitos play a significant role in the circulation and, probably, the spread of dirofilariasis in Tomsk Region. Conclusion: 1. Dirofilariae are widespread within Tomsk Region. The northernmost border of the Dirofilaria repens spread is 60° 44' and that of D. immitis - 58° 32' N. The northernmost border of the D. repens transmission is 59° N. 2. The contribution made by malaria mosquitos to the spread of dirofilariasis in Tomsk Region is as high as that of other blood-sucking mosquitos. 3. Anopheles daciae, An. messeae and An. beklemishevi are the vectors of Dirofilaria repens and D. immitis. Anopheles beklemishevi get infected less often than the two remaining species. 4. The invasion extensiveness of malaria mosquitos is higher on the right bank of the River Ob. 5. Mixed invasions and superinvasions of malaria mosquitos with dirofilariae are frequent phenomena for Tomsk Region. The article contains 4 Figures, 3 Tables, 55 References. The Authors declare no conflict of interest.

A new species of Rhabdias (Nematoda: Rhabdiasidae), a lung parasite of Pristimantis chiastonotus (Anura: Strabomantidae) from the Brazilian Amazon: description and phylogenetic analyses.

Rhabdias Stiles and Hassal, 1905 comprises approximately 90 species of parasitic lung nematodes of amphibians and reptiles that have a wide distribution, with 21 species occurring in the Neotropics. In the present study, we describe Rhabdias waiapi n. sp. found parasitizing the lungs of the anuran species Pristimantis chiastonotus from the Amazon Biome in the Amapá State, Northern Brazil. The new species is characterized by havingan elongated body, expansions of the cuticular inflation in the anterior end that become more discrete along the body, an anterior end with a slight constriction at the level of the esophageal apex with four rounded subapical elevations of the body wall, six lips, four near the edge of the oral opening and two more distant lateral ones, and a gradually tapering elongated tail. In addition, molecular analyses and phylogenetic reconstructionswere made, with sequences from the coding region of the mitochondrial cytochrome c oxidase subunit I gene. Those resultsstrongly support the status of the new taxon, which formed a poorly supported clade with Rhabdias sp. 5 from Anolis brasiliensis from Northeast Brazil. Rhabdias waiapi n. sp. is the 19th species of the genus described in the Neotropics for amphibians, the 10th in Brazil, the second described from hosts of the family Strabomantidae from the Neotropical region, and the first amphibian nematode species described in the Amapá State.

Phytonematodes as a limiting biotic factor of agricultural production in the world (review)

Purpose. To analyze domestic and foreign scientific literature on the species composition and harmfulness of the world's most dangerous parasitic species of phytonematodes in crops.
 Results. Today, according to the available literature, the most dangerous species of phytonematodes include: gall nematode (Meloidogyne spp.), cyst-forming nematode (Heterodera spp. and Globodera spp.), root lesion nematode (Pratylenchus spp.), banana drill nematode (Radoholus similis), stem nematode (Ditylenchus dipsaci), pine stem nematode (Bursaphelenchus xylophilus), reniform nematode (Rotylenchulus reniformis), xiphinema index (Xiphinema index), false head nematode (Nacobbus aberrans), and rice leaf nematode (Aphelenchoides besseyi).
 Conclusions. The results of research on the prevalence and harmfulness of parasitic nematode species in crops convince us of the need for a more detailed study of this group of microorganisms. Due to the rapid development of molecular genetic methods in the last decade, scientists have been able to expand and improve their knowledge of identifying species, races and pathotypes of phytonematodes, their biological and environmental characteristics, and most importantly, to discover and understand extremely complex mechanisms of parasite and host plants. Nematologists are confident that further research in these and other areas in the future will create a basis for developing a new strategy for long-term and environmentally safe control of these dangerous plant parasites.

Lurking in the water: testing eDNA metabarcoding as a tool for ecosystem-wide parasite detection.

In the light of global biodiversity change and emerging disease, there is an urgent need to establish efficient monitoring programmes of parasites in aquatic ecosystems. However, parasite identification is time-consuming, requires a high degree of taxonomic expertize and in general requires lethal sampling. The use of environmental DNA methodology to identify parasites has the potential to circumvent these limitations. This study evaluates the use of eDNA metabarcoding to detect the presence of all species of nematode and platyhelminth parasites in two New Zealand lakes. We developed two novel metabarcoding primer pairs targeting a region of cytochrome oxidase I gene (COI) specific to platyhelminths and nematodes. We successfully detected parasite DNA in both lakes. Platyhelminth DNA yield was in general greater than nematode DNA yield. This most likely results from the larger biomass of the former quantified using traditional methods, or the presence of free-swimming life stages in the life cycle of many platyhelminths. By using eDNA, we did not detect all expected parasite families revealed through traditional methods, likely due to a lack of sequencing data available from public databases such as GenBank. As such, genetic resources need to include full reference sequences if parasitology is to truly harness eDNA to characterize and monitor parasite biodiversity in natural systems.

DESCRIPTION OF PRATYLENCHUS SIDDIQI N. SP. FROM BANANA (MUSA ACUMINATA L.) MALIR CANTT, KARACHI, SINDH, PAKISTAN

During the surveys for isolation of plant and soil nematodes from different fruit of Sindh and Balochistan, different plant and soil nematodes were found. The new species was captured from banana (Musa acuminata L.) vegetation at Malir Cantt. Karachi, Sindh. Soil sample analysis revealed that the new species of plant parasitic nematode, Pratylenchus siddiqi n. sp. It is characterized by body posture irregularly curved after fixation, lateral field with six incisures, 2 annuli in the cephalic region, stylet = 15-16 μm long, V%= 71-78, tail sub-cylindrical to conoid with smooth terminus and the absence of males. Present paper deals with detailed taxonomical studies of new species with measurements, descriptions, illustrations and microphotographs.