Parasitic Nematode Infections Research Articles

Gastrointestinal parasites of wild Bornean orang-utans (Pongo pygmaeus) in a habitat affected by wildfire smoke

Wildfires are becoming increasingly frequent and severe in the tropical peatlands of Southern Borneo, with major consequences for both wildlife and people that inhabit them. Burning peat releases vast amounts of toxic smoke that, when inhaled, can cause a plethora of health-related issues. With some of the largest remaining populations of Bornean orang-utans (Pongo pygmaeus) being found in peatland forests, wildfires are becoming one of the greatest threats to this Critically Endangered ape, yet the effects of the toxic smoke on their health are unknown. Wildfire has long been known to influence wildlife disease by reducing populations of free-living parasites in the environment (thus altering host exposure), and there is a growing body of evidence to suggest that smoke may affect host susceptibility to such parasites by diminishing physiological condition and immune function. In this study, we investigated parasitic nematode infections in wild Bornean orang-utans inhabiting a drained peatland forest prone to fire and smoke. We identified four gastrointestinal nematode taxa that varied significantly in their prevalence and intensity. Overall prevalence of nematode infection was high, but intensity was relatively low. We present some evidence for an increase the prevalence and intensity of certain nematode taxa after the wildfire smoke event. Namely, an increase in the prevalence of Enterobius spp. and Trichuris spp., and an increase in the intensity of hookworm infections, after the smoke period. We identify the need for multi-year, multi-fire event research to increase sample sizes, along with measuring endocrinological markers of physiological condition, in tandem with parasitological monitoring, to gain a more comprehensive understanding of the impacts of environmental changes on orang-utan health.

PSX-24 Effects of dietary protein level and gastrointestinal nematode parasite infection on carcass and non-carcass yield and meat composition of goats

Abstract A study was conducted to evaluate carcass and non carcass yield of parasite challenged goats, parasitized (INF) or non parasitized (NIF) with gastrointestinal nematode parasite Haemonchus contortus. Goats were fed either high protein (HP) diet containing 24% CP or low protein (LP) diet containing 20% CP. Sixteen growing, intact male meat goats were divided into two main groups of INF and NIF goats and were further divided into two groups of four goats and fed either a high (24% CP) or low (20% CP) containing diet. At the end of the study, empty (fasted) body weights were recorded after an overnight fast and animals transported to a commercial abattoir, and harvested. The weights of the hot carcass, blood and non-carcass pool, which included head, hide and visceral organs (intestine, lung, liver, kidney and spleen), and blood were recorded. Carcass yield was evaluated as dressing percentage (hot carcass weight/empty body weight). There was no difference (P > 0.05) in carcass yield (%), (HP diet=53.77 and LP diet=54.70; INF=53.85 and NIF=54.62); blood (gm) (HP diet=1029.52 and LP diet=1146.47) and INF = 1142.45 and NIF = 1032.54), head and hide (gm) (HP diet = 5645.32 and LP diet = 970.54; INF = 6221.32 and NIF = 5394.54); visceral organs (gm) (HP diet = 4151.66 and LP diet = 4740.92; INF = 4728.35 and NIF = 4164.23). The results of this study showed that supplementation of high dietary protein level above animals need may not be beneficial in improving the variables monitored against Haemonchosis.

Quantitative tests of albendazole resistance in Caenorhabditis elegans beta-tubulin mutants

Benzimidazole (BZ) anthelmintics are among the most important treatments for parasitic nematode infections in the developing world. Widespread BZ resistance in veterinary parasites and emerging resistance in human parasites raise major concerns for the continued use of BZs. Knowledge of the mechanisms of resistance is necessary to make informed treatment decisions and circumvent resistance. Benzimidazole resistance has traditionally been associated with mutations and natural variants in the C. elegans beta-tubulin gene ben-1 and orthologs in parasitic species. However, variants in ben-1 alone do not explain the differences in BZ responses across parasite populations. Here, we examined the roles of five C. elegans beta-tubulin genes (tbb-1, mec-7, tbb-4, ben-1, and tbb-6) in the BZ response as well as to determine if another beta-tubulin acts redundantly with ben-1. We generated C. elegans strains with a loss of each beta-tubulin gene, as well as strains with a loss of tbb-1, mec-7, tbb-4, or tbb-6 in a genetic background that also lacks ben-1. We found that the loss of ben-1 conferred the maximum level of resistance following exposure to a single concentration of albendazole, and the loss of a second beta-tubulin gene did not alter the level of resistance. However, additional traits other than larval development could be affected by the loss of additional beta-tubulins, and the roles of other beta-tubulin genes might be revealed at different albendazole concentrations. Therefore, further work is needed to fully define the possible roles of other beta-tubulin genes in the BZ response.

Evaluating anthelmintic activity through Caenorhabditis elegans egg hatching assay

The Caenorhabditis elegans egg hatching methodology is a valuable tool for assessing the anthelmintic activity of drugs and compounds and evaluating anthelmintic drug efficacy.Isolated eggs from gravid adults are exposed to different concentrations of selected drugs and the percentage of egg hatching is determined with respect to the control condition. The assay allows the construction of concentration-response curves and determination of EC50 or EC90 values for egg hatching inhibition. Also, it allows measurements of inhibition as a function of time of exposure.This approach addresses the urgent need for new anthelmintics, as resistance to current treatments poses a significant challenge in parasitic nematode infection. This resistance not only affects humans but also animals and plants, causing significant economic losses in livestock farming and agriculture.By using the free-living nematode C. elegans as a parasitic model organism, researchers can efficiently screen for potential treatments and assess drug combinations for synergistic effects. Importantly, this assay offers a cost-effective and accessible alternative to traditional methods, eliminating the need for specialized infrastructure, hosts, and trained animal maintenance personnel. Additionally, the methodology closely mimics natural conditions, providing insights into egg development and potential therapeutic targets.This method allows for evaluating the direct negative impact of drugs on egg hatching, which correlates with long-term anthelmintic effects, offering advantages in preventing or reducing the transmission and spread of worm infections by eggs.Overall, this approach represents a significant advancement for anthelmintic discovery, offering both practical applications and avenues for further scientific research.•The C. elegans egg hatching assay is a robust and effective method for assessing the anthelmintic potential of various drugs and compounds, allowing the generation of concentration-response curves.•By leveraging the free-living nematode C. elegans as a parasitic model organism, this method facilitates efficient screening of potential treatments and evaluation of drug combinations.•The method addresses the urgent need for new anthelmintics, offering a cost-effective and accessible alternative to traditional approaches.

The Influence of Flock Variation, Sample Size, Flock Size and Mean Egg Count on the Accuracy and Precision of the Estimated Mean Egg Count

The control of parasitic nematode infection in sheep and other animals is threatened by the evolution of drug resistance in parasite populations. One recommendation to delay the onset of drug resistance is to estimate the flock mean faecal egg counts by sampling a subpopulation and to treat sheep only when egg counts are high. However, there is little research on the accuracy and precision of estimates of the flock mean obtained from samples. In silico sampling was used to quantify the influence of flock variation, sample size, flock size and mean egg count on the accuracy and precision of the estimated mean egg count. Commonly used and recommended sampling schemes gave alarmingly imprecise estimates of the true flock means. Simply providing a point estimate of the flock egg count can be seriously misleading. Therefore, quantiles were provided for the proportion of estimates in a plausible scenario that is likely to require treatment. It may be more informative to use these quantiles to predict the probability that the true flock mean is sufficiently high to consider treatment.

VND Genes Redundantly Regulate Cell Wall Thickening during Parasitic Nematode Infection.

Plant parasitic root-knot nematodes are major agricultural pests worldwide, as they infect plant roots and cause substantial damages to crop plants. Root-knot nematodes induce specialized feeding cells known as giant cells (GCs) in the root vasculature, which serve as nutrient reservoirs for the infecting nematodes. Here, we show that the cell walls of GCs thicken to form pitted patterns that superficially resemble metaxylem cells. Interestingly, VASCULAR-RELATED NAC-DOMAIN1 (VND1) was found to be upregulated, while the xylem-type programmed cell death marker XYLEM CYSTEINE PEPTIDASE 1 was downregulated upon nematode infection. The vnd2 and vnd3 mutants showed reduced secondary cell wall pore size, while the vnd1 vnd2 vnd3 triple mutant produced significantly fewer nematode egg masses when compared with the wild type. These results suggest that the GC development pathway likely shares common signaling modules with the metaxylem differentiation pathway and VND1, VND2, and VND3 redundantly regulate plant-nematode interaction through secondary cell wall formation.

Prevalence and Risk Factors of Parasitic Gastrointestinal Nematode Infections of Donkeys in Southern Ethiopia.

Gastrointestinal (GIT) parasites cause sickness and mortality in working donkeys, reducing their productivity. A cross-sectional study was done in the Damot Gale district of southern Ethiopia from November 2020 to June 2021 to determine the frequency of donkey GIT nematode parasite infection and to examine its related risk factors. Overall, 514 simple randomly selected donkeys from peasant associations were sampled for the coprological examination of gastrointestinal nematode infection. The flotation technique was employed to identify parasite eggs in feces. The total prevalence of parasitic gastrointestinal nematodes was 71.79% (95% CI: 67.73-75.52). The most prevalent nematodes were Strongyles (37.74%), Parascaris equorum (11.28%), Strongyloides (7.20%), and combined infections of Strongyles and Parascaris (14.01%) and Strongyles and Strongyloides (1.56%). The association between the prevalence of parasitic GIT nematode infections and body conditions score was statistically significant (p < 0.05). Comparatively, donkeys with semi-intensified systems were five times (OR = 5.36) and those with medium body condition were twice (OR = 1.94) had a higher risk of infection than donkeys with intensive systems and good body condition scores, respectively. In conclusion, the current study indicated that gastrointestinal nematode parasites of donkeys are highly prevalent in the study area. Thus, regular deworming, proper housing, and feeding management were recommended to improve the health and productivity of donkeys in the research area.

136 Evaluation of internal parasite burden in grazing beef cattle in North Carolina over a production lifecycle

Abstract Gastrointestinal nematode (GIN) parasite infections can be detrimental to not only cattle health and immunity, but also result in economic loss and poor performance. Cattle grazing in the southeast are challenged even further by the favorable environmental conditions for parasite development, especially those animals who have yet to develop an immunity to combat parasitism. To diminish potential economic and performance-based losses, many beef producers treat animals for GIN parasites with anthelmintics on a regular basis without proper diagnosis. Anthelmintic resistance(AR) develops when deworming products are overused and misused. To minimize the development of AR, selective deworming and sustainable management practices should be implemented. However, the severity of parasite burden over the production cycle needs to be better understood in beef cattle herds before recommendations can be made. Thus, the objective was to investigate the rates of GIN parasite infections through fecal egg counts (FEC) and the impact on body weight (BW) and body condition score (BCS). Angus-based cattle (6 mo-13 yr, n = 1,154) on a were utilized from five different research and educational herds across North Carolina. Cattle were categorized based on their age at the start of the project as either calves (n = 446), yearling heifers (n = 205), 2 year old (n = 260), 3-5 year old (n = 501), or 6+ year old (n = 206). Starting in September, FEC, BW, and BCS were collected and analyzed every 90 d at critical production timepoints (calving, breeding, weaning, and 90d post-weaning) to monitor the severity of GIN parasite challenge. Cattle on study were not treated with anthelmintics regardless of parasite load, with the exception of calves at four of the locations at the time of weaning. All data were analyzed using Proc MIXED in SAS with repeated measures. Statistical significance was declared at P ≤ 0.05 and a trend at 0.10 &amp;gt; P &amp;gt; 0.05. Age of cattle had an impact on FEC overall (P &amp;lt; 0.05), however, there was no difference between FEC of mature cattle over 3 yr (4.29 ± 4.9 eggs/gm). Calves had the greatest FEC (120.59 ± 4.2 eggs/gm) while cattle 6+ yr had the least (3.68 ± 4.5 eggs/gm). Cattle age at each location affected BCS and BW (P &amp;lt; 0.05). Between age groups across locations, time had an impact on FEC, BW, and BCS (P &amp;lt; 0.05). There was also a tendency (P = 0.6) for location to impact FEC. Calf sex did not affect (P &amp;gt; 0.05) FEC. Further FEC analysis of cattle under 2 yrof age is required to better understand when a natural immune response to GIN parasite infections develops.

Equine enteroid-derived monolayers recapitulate key features of parasitic intestinal nematode infection

Stem cell-derived organoid cultures have emerged as attractive experimental models for infection biology research regarding various types of gastro-intestinal pathogens and host species. However, the large size of infectious nematode larvae and the closed structure of 3-dimensional organoids often hinder studies of the natural route of infection. To enable easy administration to the apical surface of the epithelium, organoids from the equine small intestine, i.e. enteroids, were used in the present study to establish epithelial monolayer cultures. These monolayers were functionally tested by stimulation with IL-4 and IL-13, and/or exposure to infectious stage larvae of the equine nematodes Parascaris univalens, cyathostominae and/or Strongylus vulgaris. Effects were recorded using transcriptional analysis combined with histochemistry, immunofluorescence-, live-cell- and scanning electron microscopy. These analyses revealed heterogeneous monolayers containing both immature and differentiated cells including tuft cells and mucus-producing goblet cells. Stimulation with IL-4/IL-13 increased tuft- and goblet cell differentiation as demonstrated by the expression of DCLK1 and MUC2. In these cytokine-primed monolayers, the expression of MUC2 was further promoted by co-culture with P. univalens. Moreover, live-cell imaging revealed morphological alterations of the epithelial cells following exposure to larvae even in the absence of cytokine stimulation. Thus, the present work describes the design, characterization and usability of an experimental model representing the equine nematode-infected small intestinal epithelium. The presence of tuft cells and goblet cells whose mucus production is affected by Th2 cytokines and/or the presence of larvae opens up for mechanistic studies of the physical interactions between nematodes and the equine intestinal mucosa.

IDENTIFICATION AND PREVALENCES PARASITE NEMATODE ON ETAWA CROSSBREED GOAT IN SUKAWATI SUBDISTRICT, GIANYAR REGENCY

Etawa crossbreed goat have farmed in Sukawati Subdistrict, Gianyar Regency. As a ruminant, goat had risked to get infected by nematode parasites in Sukawati Subdistrict, Gianyar Regency. This study had known to identification and prevalences parasite nematode cluster in Sukawati Subdistrict, Gianyar Regency. This study had bought some sample then have preserved with 10% formalin. The result is, prevalence of nematode parasite is 14% and nematode who can identification is Skrjabinema spp.; Strongyloides sp.; and Strongyl-type. Prevalence nematode in Sukawati Subdistrict more less than another place. From the results who have, cage cleanliness should be upgrade for minimalize nematode parasite infection.

Multi-infection parasitic nematodes in deer at Waru Farm Land, Ciampea, Bogor Regency

Deer is a protected wild animal in Indonesia, and currently, deer are often kept and used as part of amusement rides in recreational areas. This study aimed to identify the incidence of worm infections in deer kept in the Waru Farm Land recreation area in Tegalwaru, Ciampea Bogor. Nine deer were kept by Waru Farm Land, consisting of spotted deer and Timor deer. Samples were collected immediately after the deer had defaecated. Stool sample examinations included the flotation test, McMaster’s test, and multilevel filtration. The examination results showed that one deer had multiple parasitic nematode infections. Examination revealed strong and trichurid-type eggs. The degree of infection showed a very mild value, namely less than 50 EPG, so it can be concluded that worm infection in deer at Waru Farm Land is very low. Treatment by administering anthelmintics to deer that were positively infected with worms should be given, as well as preventing infection in other deer.

Mucosal Immunity of Major Gastrointestinal Nematode Infections in Small Ruminants Can Be Harnessed to Develop New Prevention Strategies.

Gastrointestinal parasitic nematode (GIN) infections are the cause of severe losses to farmers in countries where small ruminants such as sheep and goat are the mainstay of livestock holdings. There is a need to develop effective and easy-to-administer anti-parasite vaccines in areas where anthelmintic resistance is rapidly rising due to the inefficient use of drugs currently available. In this review, we describe the most prevalent and economically significant group of GIN infections that infect small ruminants and the immune responses that occur in the host during infection with an emphasis on mucosal immunity. Furthermore, we outline the different prevention strategies that exist with a focus on whole and purified native parasite antigens as vaccine candidates and their possible oral-nasal administration as a part of an integrated parasite control toolbox in areas where drug resistance is on the rise.

Pharmacological effects of monoterpene carveol on the neuromuscular system of nematodes and mammals.

The control of parasitic nematode infections relies mostly on anthelmintics. The potential pharmacotherapeutic application of phytochemicals, in order to overcome parasite resistance and enhance the effect of existing drugs, is becoming increasingly important. The antinematodal effects of carveol was tested on the free-living nematode Caenorhabditis elegans and the neuromuscular preparation of the parasitic nematode Ascaris suum. Carveol caused spastic paralysis in C. elegans. In A. suum carveol potentiated contractions induced by acetylcholine (ACh) and this effect was confirmed with two-electrode voltage-clamp electrophysiology on the A. suum nicotinic ACh receptor expressed in Xenopus oocytes. However, potentiating effect of carveol on ACh-induced contractions was partially sensitive to atropine, indicates a dominant nicotine effect but also the involvement of some muscarinic structures. The effects of carveol on the neuromuscular system of mammals are also specific. In micromolar concentrations, carveol acts as a non-competitive ACh antagonist on ileum contractions. Unlike atropine, it does not change the EC50 of ACh, but reduces the amplitude of contractions. Carveol caused an increase in Electrical Field Stimulation-evoked contractions of the isolated rat diaphragm, but at higher concentrations it caused an inhibition. Also, carveol neutralized the mecamylamine-induced tetanic fade, indicating a possibly different pre- and post-synaptic action at the neuromuscular junction.

The New Nematicide Cyclobutrifluram Targets the Mitochondrial Succinate Dehydrogenase Complex in Caenorhabditis elegans.

Today, agriculture around the world is challenged by parasitic nematode infections. Plant-parasitic nematodes (PPNs) can cause significant damage and crop loss and are a threat to food security. For a long time, the management of PPN infection has relied on nematicides that impact not only parasitic nematodes but also other organisms. More recently, new nematicides have been developed that appear to specifically target PPN. Cyclobutrifluram belongs to this new category of nematicides. Using the nematode Caenorhabditis elegans as a model organism, we show here that cyclobutrifluram strongly impacts the survival and fertility rates of the worm by decreasing the number of germ cells. Furthermore, using a genetic approach, we demonstrate that cyclobutrifluram functions by inhibiting the mitochondrial succinate dehydrogenase (SDH) complex. Transcriptomic analysis revealed a strong response to cyclobutrifluram exposure. Among the deregulated genes, we found genes coding for detoxifying proteins, such as cytochrome P450s and UDP-glucuronosyl transferases (UGTs). Overall, our study contributes to the understanding of the molecular mode of action of cyclobutrifluram, to the finding of new approaches against nematicide resistance, and to the discovery of novel nematicides. Furthermore, this study confirms that C. elegans is a suitable model organism to study the mode of action of nematicides.

Nematicidal Characterization of Newly Synthesized Thiazine Derivatives Using Caenorhabditis elegans as the Model Organism.

In humans, animals, and agriculture, parasitic nematode infection is a very serious issue. Many drugs are being used to control nematode infections. Owing to toxicity and nematodes' resistance to the available drugs, special attention is required to synthesize new drugs that are environmentally friendly with high-level efficacy. In the present study, various substituted thiazine derivatives (1 to 15) were synthesized, and the structures were confirmed by infrared, proton (1H), and 13C NMR spectroscopies. The nematicidal potential of the synthesized derivatives was characterized using Caenorhabditis elegans (C. elegans) as a model organism. Among all synthesized compounds, 13 (LD50 = 38.95 μg/mL) and 15 (LD50 = 38.21 μg/mL) were considered the most potent compounds. Most compounds showed excellent anti-egg-hatching activity. Fluorescence microscopy confirmed that compounds 4, 8, 9, 13, and 15 displayed a high apoptotic effect. The expressions of gst-4, hsp-4, hsp16.2, and gpdh-1 genes were high in affected (treated with thiazine derivatives) C. elegans in comparison with normal C. elegans. The present research revealed that modified compounds are highly effective as they showed the gene level changes in the selected nematode. Due to structural modification in thiazine analogues, the compounds showed various modes of action. The most effective thiazine derivatives could be excellent candidates for novel broad-scale nematicidal drugs.

Root-knot nematode modulates plant CLE3-CLV1 signaling as a long-distance signal for successful infection.

Plants use many long-distance and systemic signals to modulate growth and development, as well as respond to biotic and abiotic stresses. Parasitic nematodes infect host plant roots and cause severe damage to crop plants. However, the molecular mechanisms that regulate parasitic nematode infections are still unknown. Here, we show that plant parasitic root-knot nematodes (RKNs), Meloidogyne incognita, modulate the host CLAVATA3 (CLV3)/EMBRYO SURROUNDING REGION (CLE)-CLV1 signaling module to promote the infection progression. Plants deficient in the CLE signaling pathway show enhanced RKN resistance, whereas CLE overexpression leads to increased susceptibility toward RKN. Grafting analysis shows that CLV1 expression in the shoot alone is sufficient to positively regulate RKN infection. Together with results from the split-root culture system, infection assays, and CLE3-CLV1 binding assays, we conclude that mobile root-derived CLE signals are perceived by CLV1 in the shoot, which subsequently produce systemic signals to promote gall formation and RKN reproduction.

Study on gastrointestinal nematode parasite infections of donkey in and around shone town, Hadiya zone, Southern Ethiopia

One of the most common factors limiting donkey health and productivity is infection with gastrointestinal nematode parasites. From December 2021 to May 2022, a cross-sectional study was conducted in and around Shone town, Hadiya zone, southern Ethiopia, to estimate the prevalence of donkey GIT nematode parasite infection and to assess its associated risk factors. For the coprological examination, 384 simple randomly selected donkeys were sampled from four peasant associations. To identify parasitic eggs in feces, the standard flotation technique was used. In the donkeys examined, the overall prevalence of gastrointestinal nematodes was 75.26% Strongyles (48.17%), Parascaris equorum (11.45%), Strongyloides (5.99%), and mixed infection (Strongyles + Parascaris (9.11%) and Strongyles + Strongyloides (0.52%)) were the most commonly encountered nematodes. There was also a statistically significant difference in the prevalence of donkey gastrointestinal parasites by sex, body condition, and management system (p < 0.05). Donkeys with semi-intensified (OR = 8.99) and poor body condition (OR = 6.48) were at an increased risk of infection compared to intensive management and good body condition. In conclusion, the current study demonstrated that gastrointestinal nematodes are the major health challenges for donkeys in the study area. As a result, strategic regular deworming, improved housing, and feeding management were recommended to improve the health and productivity of donkeys in the study area.

Variation in anthelmintic responses are driven by genetic differences among diverse C. elegans wild strains.

Treatment of parasitic nematode infections in humans and livestock relies on a limited arsenal of anthelmintic drugs that have historically reduced parasite burdens. However, anthelmintic resistance (AR) is increasing, and little is known about the molecular and genetic causes of resistance for most drugs. The free-living roundworm Caenorhabditis elegans has proven to be a tractable model to understand AR, where studies have led to the identification of molecular targets of all major anthelmintic drug classes. Here, we used genetically diverse C. elegans strains to perform dose-response analyses across 26 anthelmintic drugs that represent the three major anthelmintic drug classes (benzimidazoles, macrocyclic lactones, and nicotinic acetylcholine receptor agonists) in addition to seven other anthelmintic classes. First, we found that C. elegans strains displayed similar anthelmintic responses within drug classes and significant variation across drug classes. Next, we compared the effective concentration estimates to induce a 10% maximal response (EC10) and slope estimates of each dose-response curve of each strain to the laboratory reference strain, which enabled the identification of anthelmintics with population-wide differences to understand how genetics contribute to AR. Because genetically diverse strains displayed differential susceptibilities within and across anthelmintics, we show that C. elegans is a useful model for screening potential nematicides before applications to helminths. Third, we quantified the levels of anthelmintic response variation caused by genetic differences among individuals (heritability) to each drug and observed a significant correlation between exposure closest to the EC10 and the exposure that exhibited the most heritable responses. These results suggest drugs to prioritize in genome-wide association studies, which will enable the identification of AR genes.

Occurrence and Distribution of Root-Knot Nematodes in Kiwifruit Orchard

The study was conducted to investigate the infestation and distribution of plant-parasitic nematodes on kiwi orchards in Korea. Plant parasitic nematodes genus and densities were investigated at a total of 102 sites in Jeollanam-do, Gyeongsangnam-do, and Jeju-do, which are the main production areas of domestic kiwi orchards. Plant parasitic nematodes detected were of 9 genera, including root-knot nematodes (Meloidogyne spp.), spiral nematodes (Helicotylenchus spp.), and needle nematodes (Paratylenchus spp.), and 56% of the 102 plantations were infected with root-knot nematodes. Root-knot nematodes were found to be the most important plant parasitic nematode in domestic kiwi orchards. The average density of root-knot nematodes is 97 per 300 cm&lt;sup&gt;3&lt;/sup&gt; soil, and there is concern about the kiwi yield reduction. As a result of identifying the root-knot nematode species: M. arenaria, M. hapla, M. incognita, and M. javanica. Among them, M. arenaria is the most dominant. As the plant parasitic nematode infection route in fruit trees is often spread through the transplantation of infected seedlings, attention should be paid to the production of nematode-free plants during the production and supply of kiwifruit plants.

Parasitic nematode secreted phospholipase A2 suppresses cellular and humoral immunity by targeting hemocytes in Drosophila melanogaster.

A key aspect of parasitic nematode infection is the nematodes' ability to evade and/or suppress host immunity. This immunomodulatory ability is likely driven by the release of hundreds of excretory/secretory proteins (ESPs) during infection. While ESPs have been shown to display immunosuppressive effects on various hosts, our understanding of the molecular interactions between individual proteins released and host immunity requires further study. We have recently identified a secreted phospholipase A2 (sPLA2) released from the entomopathogenic nematode (EPN) Steinernema carpocapsae we have named Sc-sPLA2. We report that Sc-sPLA2 increased mortality of Drosophila melanogaster infected with Streptococcus pneumoniae and promoted increased bacterial growth. Furthermore, our data showed that Sc-sPLA2 was able to downregulate both Toll and Imd pathway-associated antimicrobial peptides (AMPs) including drosomycin and defensin, in addition to suppressing phagocytosis in the hemolymph. Sc-sPLA2 was also found to be toxic to D. melanogaster with the severity being both dose- and time-dependent. Collectively, our data highlighted that Sc-sPLA2 possessed both toxic and immunosuppressive capabilities.