Nematode Larvae Research Articles

Use of fine capillaries for cryopreservation of Caenorhabditis elegans by vitrification

Caenorhabditis elegans is an exceptional model organism. More than twenty thousand different strains have been developed, increasing knowledge on countless topics. However, the traditional method to cryopreserve this nematode, based on slow freezing, usually reaches recovery rates of around 35% for the L1 and L2 larval stages. Here, we propose two alternative methods to cryopreserve this nematode based on vitrification that are applicable in common laboratories and allow the selective individual cryopreservation of this organism. These new methods require ultra-high warming rates, which are achieved by employing very thin capillaries as the nematode container, and a very low final concentration of cryoprotectants, which, as compared to slow freezing, reduce toxicity damage. The recovery rate was 98.5% for larvae (L1 – L4) and 84.3% for adults. Given these results, our procedures offer an alternative to cryopreserve this nematode (larvae and adults) with higher recovery rates, avoiding expensive requirements. Indeed, it only needed a container with liquid nitrogen and a warming bath for water at 37 °C. The high performance of this approach has been revealed by preserving the long-term memory and, probably, the connectome of this nematode.

Occurrence and prevalence of third-stage larvae of the Anisakidae family in Macrouridae species captured from bathyal depths of Sagami Bay, Japan

Anisakiasis is the prevailing form of foodborne illness in Japan, with Anisakidae larvae, specifically Anisakis simplex sensu stricto, serving as its causative agents. These larvae are commonly found in mackerel, sardines, and skipjacks retailed at fresh fish establishments. While the infection rates of Anisakidae larvae in these surface-dwelling fish have been extensively studied, their prevalence in deep-sea fish species remains inadequately understood. This investigation aims to determine the infection rates of Anisakidae larvae in three Macrouridae species—namely Coryphaenoides acrolepis, Coelorinchus japonicus, and Coelorinchus macrochir—which represent the most significant inhabitants of the deep-sea realm. Employing artificial digestion techniques, we successfully retrieved all internal contents of the fish, including the nematode larvae. Some Anisakidae larvae were morphologically identified as A. simplex sensu lato and further identified to species by PCR-RFLP analysis. Two larvae showed a band pattern that appeared to be a hybrid between A. simplex sensu stricto and A. berlandi, which after sequence analysis was considered to be an intraspecific variation of A. berlandi. On the other hand, species considered to be unknown were sequenced and phylogenetic analysis was carried out along with identified larvae. The findings indicate that A. simplex sensu stricto was notably more abundant in C. acrolepis, obtained at a depth of 1000 m. In C. japonicus and C. macrochir, captured at a depth of 400 m, a considerable number of Skrjabinisakis paggiae and Pseudoterranova ceticola, were detected in the deep-sea dwelling Kogia breviceps and K. sima as definitive hosts, were detected. Notably, a single C. macrochir harbored seven species of Anisakidae larvae, with an infection tally of nearly 200 individuals of S. paggiae. Thus, a substantial prevalence of Anisakidae larvae in the deep-sea-dwelling Macrouridae species potentially plays a significant role in the transmission pathway to cetaceans as their final hosts.

Anisakis simplex and urticaria. What we know about its real incidence and management in dermatological settings?

Acute or chronic infections have been described among causes of chronic urticaria (CU). Anisakidosis is a human disease caused by the ingestion of larval nematodes of the family Anisakidae. The infestation is acquired by eating raw seafood or undercooked fish and squid. There are considerable variations in the frequency of underlying causes in the different studies and in different countries, such as differences in diets and the prevalence of infections. Anisakis simplex has been recognized as a trigger of both acute and CU manifestations. However, there is still a lack of evidence about its management and treatment in dermatology. We, therefore, reviewed some biologic properties of Anisakis simplex in order to understand the relationship between its biology and the mechanism it uses to establish chronic dermatological conditions such as urticaria and cause late complications. In addition, we herein report some concerns about the effectiveness of systemic treatment in preventing complications and management in dermatological settings.

Detection and Biocontrol of citrus nematode Tylenchulus semipenetrans in Wasit province

This study had been conducted to detecte the existence of citrus nematode Tylenchulus semipenetrans in Wasit province, and to evaluate the effect of three biocontrol agents (T.harzianum, T.hamatum, Paecilomyces lilacinus) on larvae and eggs of this nematode in laboratory. The results of the existence of nematode in the areas of study shown significant variation between the studied areas and the highest population of larvae and females were recorded in Al-ssaouira district, where the number of larvae was 8.5 larva/250 g soil and 54.6 Female / 1 g of roots and the lower population was recorded in the AL-Muwafaqiya district which were 2.47 larva/250 g soil and 33.6 female/1g roots. The results also revealed that all bioagentsare effective in parasitizing the eggs and the more effective one is T.hamatum where the percent of parasitism was 85.49%. Field Experiment revealed the capacity of all tested fungi in reducing the population of nematode larvae in treated soil compared with non treated soil and the highest percent of reduction recorded in the case of Trichoderma harzianum which was 76.9% compared with the control 28.2%.

Fungal Endophytes: A Potential Application in Integrated Plant Health Management

Fungal endophytes are asymptomatic inhabitants of plant tissues in most plant species, providing tissue-specific protection from disease and reducing crop yield losses by 30 to 50% annually. They can increase plant fitness by inhibiting biotic and abiotic stressors, promote plant growth and development, and reduce crop yield losses. Endophytes enhance plant resistance to fungal pathogens by strengthening cell walls, increasing photosynthesis and promoting plant defense responses. They produce antibacterial and antifungal compounds that protect plants against bacterial pathogens, such as javanicin, which is effective against Bacillus species and Escherichia coli. Endophytic fungi can produce broad-spectrum antimicrobial compounds, some of which can be used as biocontrol agents for phytopathogenic bacteria. They also reduce viral diseases by increasing plant defenses or preventing viruses from spreading. Plant-parasitic nematodes attack plant roots and stems, creating wounds through which secondary opportunistic fungal, bacterial, or viral pathogens can enter. Fungi can inhibit nematode growth and spread by producing nematocidal compounds, parasitizing nematode larvae, or using hyphal loops for nematode capture. Endophytic fungi are a rich source of novel natural compounds, have a high level of biodiversity, and may produce pharmaceutical-significant compounds. Further molecular research is necessary to facilitate the recognition of endophytes carrying host genes.

Efficacy in US cattle of a novel fixed-dose combination injectable (0.2 mg/kg doramectin + 6.0 mg/kg levamisole hydrochloride) against naturally acquired gastrointestinal nematode infections

Reports of macrocyclic lactone (ML) loss of efficacy suggest ML resistance in gastrointestinal nematodes (GINs) is a growing problem in the US cattle industry. Empirical and modeling data support combining an ML and second anthelmintic from a different drug class to help ML resistance development while effectively treating existing resistant parasite populations. Here, we present a novel fixed-dose combination injectable (FDCI) solution for cattle that delivers 0.2 mg of doramectin and 6.0 mg of levamisole hydrochloride (HCl) per kg of body weight. Field studies were conducted at six sites across the Midwest United States to investigate the efficacy of a single administration of the FDCI in treating common cattle GINs. Cattle (n = 425) with GIN infections confirmed by fecal egg count (FEC) on Day −10( ± 2) were randomly allocated to the control (saline) or treatment (FDCI) group. On Day 0, pre-treatment fecal samples were collected, and cattle were administered a single subcutaneous injection of saline (n = 106) or FDCI (n = 319). Post-treatment fecal samples were collected on Day 14. Fecal egg count reduction tests (FECRTs) were conducted using Day 0 and Day 14 FECs. Efficacy was evaluated using Day 14 FECs (FDCI-treated versus saline-treated). Within treatment, samples collected on Days 0 and 14 with ≥ 20 eggs per gram (EPG) were cultured for nematode larvae recovery and identification. Day −10 FECs for enrolled animals were similar between treatment groups. Coprocultures from cattle with FEC ≥ 20 EPG (n = 68 saline; n = 211, FDCI) on Day 0 showed the presence of Cooperia punctata, Ostertagia spp., Haemonchus spp., C. oncophora, Oesophagostomum spp. and Trichostrongylus spp. Day 14 FECs for FDCI-treated cattle were significantly reduced (0–3 EPG) compared to saline-treated cattle (0–1252 EPG) (p ≤ 0.0042). At all study sites, the efficacy of the new FDCI was ≥ 99.4% and the FECR was 0.99 or 1.00. Day 14 coprocultures from control cattle showed infections of common GIN genera, confirming the efficacy of the FDCI against GINs in the field. A single administration of the doramectin + levamisole HCl combination injectable effectively treats common and economically important cattle GINs.

Proliferative strongyloidiasis in a colony of colubrid snakes.

Strongyloides are small rhabditid nematodes primarily associated with enteric disease in a variety of animal species, including reptiles. Strongyloides spp life stages were associated with a disease outbreak in a large breeding colony of snakes. Multiple Pantherophis and Lampropeltis colubrids exhibited respiratory distress, anorexia, stomatitis, facial deformation, and waning body condition that resulted in death or necessitated euthanasia. Postmortem examinations of 13 snakes revealed epithelial hyperplasia and inflammation of the alimentary and respiratory tracts associated with varying numbers of adult and larval nematodes and embryonated or larvated ova. In a subset of snakes, aberrant nematode migration was also observed in the eye, genitourinary system, coelom, and vasculature. Histomorphology and gross examination of parasitic adult female nematodes from host tissues were consistent with a Strongyloides spp. Sedimented fecal material from 101/160 (63%) snakes housed in the affected facility was positive for nematodes and/or larvated ova. Polymerase chain reaction amplification and sequencing of portions of the 18S and 28S ribosomal ribonucleic acid (RNA) genes and the internal transcribed spacer region of adult female parasites and positive fecal samples supported the diagnosis of strongyloidiasis. Strongyloides spp possess a unique life cycle capable of alternating between parasitic (homogonic) and free-living (heterogonic) stages, resulting in the production of directly infective larvae. Commonly utilized husbandry practices in reptile collections can amplify the numbers of infective larvae generated in the captive environment, increasing the risk for rhabditid hyperinfections. This report documents morbidity, mortality, and non-enteric disease manifestations due to Strongyloides hyperinfections in a captive colubrid snake colony.

An initial investigation of the predatory activity of the phoretic mites of dung beetles, Macrocheles sp. (Mesostigmata: Macrochelidae), on the gastrointestinal nematode of sheep Haemonchus contortus (Strongylida: Trichostrongylidae)

Worldwide increasing levels of anthelmintic resistance are pushing farmers and health advisors towards a more sustainable management of gastrointestinal nematodes (GIN), one of the greatest threats to the viability of grazing small ruminant production systems, and to these animals’ welfare. These Strongyloidea develop freely in livestock dung, where they are exposed to predatory organisms that can eventually break their cycle. The aim of this study was to investigate the effect of phoretic mites of dung beetles Macrocheles sp. (Macrochelidae) on the gastrointestinal nematode Haemonchus contortus (Rudolphi, 1803) that has a free-living larval stage that evolves in sheep feces. Direct observations under a stereomicroscope confirmed that the studied Macrocheles mites may have an active predatory behavior on the third-stage (L3) larvae of H. contortus. In order to quantify the effects of the mites’ predation on the survival of L3 nematode larvae, we designed experimental units, replicated across five trials, and containing free-living stages of the nematode either in the presence or absence of mites. The number of H. contortus larvae that reached the third-stage was significantly reduced in the presence of mites, despite a variable intensity of the predatory effects between trials. This is the first report of a predatory activity of phoretic mites of dung beetles’ on a livestock gastrointestinal nematode. This first step encourages further studies in order to have a better quantification of this interaction, and to investigate to which extent the phoretic mites of dung beetles can impact H. contortus populations in natural conditions.

Вплив нематоди Contracaecum (Ascaris) на риб водойми-охолоджувача Запорізької атомної електростанції

Purpose: To determine species composition and localization of anisakidosis pathogens, infestation of fish species in the Zaporizhzhia NPP cooling reservoir, and identify trends in their infestation compared to monitoring epizootic studies of the last year. Methodology. In the course of the work, we used the generalized results of the studies conducted in the summer and autumn of 2021. The fish species composition in the ZNPP cooling reservoir as well as the species composition of parasites of Anisakidae family and their localization were determined. The studies were carried out using the method of incomplete parasitological dissection of fish at the laboratory. Nematode larvae were detected by visual inspection. The parasites were identified using identification keys. The detected parasites were washed with a saline and stored in 70% ethanol. For the quantitative analysis of the parasitofauna, we used such parameters as prevalence (%) and intensity (ind./ fish). Findings. The parasitological analysis showed that Contracaecum (Ascaris) larvae were found in European, channel and redtail catfishes, which were localized as cysts or free-living in the abdominal cavity. The infestation intensify reached 86 ind./fish, and prevalence reached 100%. The parasites caused hyperemia (redness) and inflammation of internal organs. At the same time, no Contracaecum larvae were found in common and silver carps. Compared to 2020, the infestation of fish was less pronounced, namely: no monogenean Dactylogirus were found on the gills of carps as well as ciliates including Trichodina and Apiosoma, which were found in small amounts on the body surface and gills of common and silver carps. The Contracaecum larvae invasion intensity in catfish decreased by 17 %. Originality. For the first time, a large tendency to the spread of Contracaecum larvae among fish of the ZNPP cooling reservoir was detected, namely in European, channel and redtail catfishes. The importance of the threat of this invasion for fish was established. Practical value. The obtained results can be used to identify timely trends in the infestation of fish by Anisakidae and to develop sanitary and preventive measures in the reservoir. Key words: nematodes, parasites Contracaecum (Ascaris), fish, ZNPP, anisakidosis, prevalence, invasion intensity, anisakids (Anisakidae).

Effects of tri-n-butyl phosphate (TnBP) on neurobehavior of Caenorhabditis elegans.

As an emerging flame retardant, organic phosphate flame retardants have been extensively used worldwide. The aim of this study is to determine the effects of TnBP on neurobehavior of Caenorhabditis elegans (C. elegans) and its mechanisms. L1 larvae of wild-type nematodes (N2) were exposed to TnBP of 0, 0.1, 1, 10, and 20 mg/L for 72 hours. Then, we observed that the body length and body width were inhibited, the head swings were increased, the pump contractions and chemical trend index were reduced, the production of reactive oxygen species (ROS) was increased, and the expression of mitochondrial oxidative stress related genes (mev-1 and gas-1) and P38 MAPK signal pathway-related genes (pmk-1, sek-1, and nsy-1) was altered. After reporter gene strains BZ555, DA1240, and EG1285 were exposed to TnBP of 0, 0.1, 1, 10, and 20 mg/L for 72 hours, the synthesis of dopamine, glutamate, and Gamma-Amino Butyric Acid (GABA) was increased. In addition, the pmk-1 mutants (KU25) led to the sensitivity of C. elegans to TnBP in terms of head swings. The results showed that TnBP had harmful effects on the neurobehavior of C. elegans, oxidative stress might be one of the mechanisms of its neurotoxicity, and P38 MAPK signal pathway might play an important regulatory role in this process. The results revealed the potential adverse effects of TnBP on the neurobehavior of C. elegans.

Morphological and Molecular Characterization of Anisakid Nematode Larvae (Nematoda: Anisakidae) in the Black Cusk eel Genypterus maculatus from the Southeastern Pacific Ocean off Peru

The back cusk eel, Genypterus maculatus (Tschudi, 1846), (Ophiidiformes: Ophiididae) is one of the benthic-demersal fish usually consumed in northern Peru. Here, we identified the third stage (L3) Anisakidae sampled from 29 specimens of G. maculatus captured off the south American Pacific coast, Lambayeque Region, Peru. A total of 20 anisakid nematode larvae were collected on the visceral surface and divided morphologically into three types (Type I–III). These larvae were identified by mtDNA Cox2 sequences analysis, which indicated that corresponded to Anisakis pegreffii Campana-Rouget and Biocca, 1955, Skrjabinisakis physeteris (Baylis, 1923) and S. brevispiculata (Dollfus, 1966) Safonova, Voronova, and Vainutis, 2021, respectively. This is the first record of S. brevispiculata in Peru. The results obtained in this study provide knowledge on the diversity and distribution of Anisakis Dujardin, 1845 and Skrjabinisakis Mozgovoi, 1951, species in the south American Pacific waters and their relevance for public health. In addition, we suggest that combined use of molecular and morphological approaches is needed to characterize L3 anisakid larvae.

An Overview of Angiostrongylus cantonensis (Nematoda: Angiostrongylidae), an Emerging Cause of Human Angiostrongylosis on the Indian Subcontinent.

Human angiostrongylosis is an emerging zoonosis caused by the larvae of three species of metastrongyloid nematodes of the genus Angiostrongylus, with Angiostrongylus cantonensis (Chen, 1935) being dominant across the world. Its obligatory heteroxenous life cycle includes rats as definitive hosts, mollusks as intermediate hosts, and amphibians and reptiles as paratenic hosts. In humans, the infection manifests as Angiostrongylus eosinophilic meningitis (AEM) or ocular form. Since there is no comprehensive study on the disease in the Indian subcontinent, our study aims at the growing incidence of angiostrongylosis in humans, alongside its clinical course and possible causes. A systematic literature search revealed 28 reports of 45 human cases from 1966 to 2022; eosinophilic meningitis accounted for 33 cases (75.5%), 12 cases were reported as ocular, 1 case was combined, and 1 case was unspecified. The presumed source of infection was reported in 5 cases only. Importantly, 22 AEM patients reported a history of eating raw monitor lizard (Varanus spp.) tissues in the past. As apex predators, monitor lizards accumulate high numbers of L3 responsible for acute illness in humans. For ocular cases, the source was not identified. Most cases were diagnosed based on nematode findings and clinical pathology (primarily eosinophilia in the cerebrospinal fluid). Only two cases were confirmed to be A. cantonensis, one by immunoblot and the other by q-PCR. Cases of angiostrongylosis have been reported in Delhi, Karnataka, Kerala, Maharashtra, Madhya Pradesh, Puducherry, Telangana, and West Bengal. With a population of more than 1.4 billion, India is one of the least studied areas for A. cantonensis. It is likely that many cases remain undetected/unreported. Since most cases have been reported from the state of Kerala, further research may focus on this region. Gastropods, amphibians, and reptiles are commonly consumed in India; however, typical preparation methods involve cooking, which kills the nematode larvae. In addition to studying rodent and mollusk hosts, monitor lizards can be used as effective sentinels. Sequence data are urgently needed to answer the question of the identity of Angiostrongylus-like metastrongylid nematodes isolated from all types of hosts. DNA-based diagnostic methods such as q-PCR and LAMP should be included in clinical diagnosis of suspected cases and in studies of genetic diversity and species identity of nematodes tentatively identified as A. cantonensis.

Top-down and bottom-up effects and relationships with local environmental factors in the water frog–helminth systems in Latvia

Semi-aquatic European water frogs (Pelophylax spp.) harbour rich helminth infra-communities, whose effects on host population size in nature are poorly known. To study top-down and bottom-up effects, we conducted calling male water frog counts and parasitological investigations of helminths in waterbodies from different regions of Latvia, supplemented by descriptions of waterbody features and surrounding land use data. We performed a series of generalized linear model and zero-inflated negative binomial regressions to determine the best predictors for frog relative population size and helminth infra-communities. The highest-ranked (by Akaike information criterion correction, AICc) model explaining the water frog population size contained only waterbody variables, followed by the model containing only land use within 500 m, while the model containing helminth predictors had the lowest rank. Regarding helminth infection responses, the relative importance of the water frog population size varied from being non-significant (abundances of larval plagiorchiids and nematodes) to having a similar weight to waterbody features (abundances of larval diplostomids). In abundances of adult plagiorchiids and nematodes the best predictor was the host specimen size. Environmental factors had both direct effects from the habitat features (e.g., waterbody characteristics on frogs and diplostomids) and indirect effects through parasite-host interactions (impacts of anthropogenic habitats on frogs and helminths). Our study suggests the presence of synergy between top-down and bottom-up effects in the water frog–helminth system that creates a mutual dependence of frog and helminth population sizes and helps to balance helminth infections at a level that does not cause over-exploitation of the host resource.

First morphological and molecular characterization of the genus Eustrongylides nematode larvae infecting fish in the Brazilian Amazon

First morphological and molecular characterization of the genus Eustrongylides nematode larvae infecting fish in the Brazilian Amazon

In vitro effect of burned pasture soil on eggs and free-living larvae of ruminant gastrointestinal nematodes

Gastrointestinal nematodes are the most expensive agent of disease currently facing the livestock production industry. Spending the beginning of their life cycle as eggs and free-living larvae, nematodes are vulnerable to a multitude of external environmental factors. Fire is a naturally occurring force of nature that has both destructive and reconstructive effects on soil characteristics which nematode stages rely on for survival. The aim of this project was to evaluate in vitro the effect of burned pasture soil (200 °C and 500 °C) on the free-living stages of ruminant nematodes. We tested the effect of burned soil on the ability of eggs to hatch and produce infective larvae, and then tested survival of infective larvae within burned soil. Adding burned soil (500 °C) to larval cultures improved larval yield compared to larval cultures containing raw soil or soil burned at a lower heat (200 °C), and raw soil improved longer term survival of infective larvae. We were able to recover significantly more larvae from samples with low soil content either as raw or soil burned at 200 °C, when compared with samples with soil burned at 500 °C. This study has shown that the survival of gastrointestinal nematodes at the L3 stage is negatively impacted by the addition of soil burned at 500 °C. Although this temperature is closest to that of a medium intensity wildfire, which is a typically destructive process in agriculture, it reduces the number of infective GIN larvae available for animals to ingest. These experiments enable us to address in vitro if post-fire soil conditions alter the number of infective larvae available on pasture, and thus the infectivity of the pasture to livestock.

Seals, fish, humans and parasites in the Baltic: ecology, evolution and history.

Evolutionary and ecological processes affecting the interactions between hosts and parasites in the aquatic environment are at display in the Baltic Sea, a young and ecologically unstable marine ecosystem, where fluctuating abiotic and biotic factors affect the parasitofauna in fish. The dynamic infections of Baltic cod, a subpopulation of the Atlantic cod (Gadus morhua Linnaeus), with third stage anisakid nematode larvae of Pseudoterranova decipiens (Krabbe, 1878) and Contracaecum osculatum (Rudolphi, 1802) have increased following a significant increase of the Baltic grey seal Halichoerus grypus (Fabricius) population in the region. Cod serves as a paratenic host and marine mammals, pinnipeds, are definitive hosts releasing parasite eggs, with faeces, to the marine environment, where embryonation and hatching of the third stage larva take place. The parasite has no obligate intermediate hosts, but various invertebrates, smaller fish and cod act as paratenic hosts transmitting the infection to the seal. Contracaecum osculatum has an impact on the physiological performance of the cod, which optimises transmission of the larva from fish to seal. Thus, a muscle mass decrease of nearly 50% may result from heavy C. osculatum infections, probably amplified by a restricted food availability. The muscle atrophy is likely to reduce the escape reactions of the fish when meeting a foraging seal. In certain regions, where fish and seals are restricted in their migration patterns, such as the semi-enclosed Baltic Sea, the predation may contribute to a severe cod stock depletion. The parasites are zoonotic and represent a human health risk, when consumers ingest insufficiently heat- or freeze-treated infected products. Marked infections of the cod were previously reported during periods with elevated seal populations (late 19th and middle 20th century) and various scenarios for management of risk factors are evaluated in an evolutionary context.

Multispecies helminth parasitism of grazing dairy cows in Germany and Austria, examined in the housing period

Helminth composition and burden data for dairy cows have not been reported for >40years for Germany and even less information is available for Austria. In the context of two recent studies, helminth parasitism was studied in 32 cows (23 from six farms in Bavaria and Tyrol; 9 from one farm in Saxony) from pasture-based dairy farms necropsied during the housing period. Helminths were enumerated and identified based on morphological characters (all helminths but rumen flukes) or molecular techniques (rumen flukes). Thirteen species of gastrointestinal nematodes and two species each of liver flukes (Fasciola hepatica, Dicrocoelium dendriticum) and rumen flukes (Calicophoron daubneyi, Paramphistomum leydeni) were recorded; no lungworms were recovered from any cow. Early fourth-stage (inhibited) larval Ostertagia species nematodes (210 to 140,600) were recovered from all cows, 31 each had adult Ostertagia ostertagi/Ostertagia lyrata (40 to 2020) and Trichostrongylus axei (10 to 53,400), 23 Oesophagostomum radiatum (1 to 242) and 20 Cooperia punctata (10 to 3330). Other nematodes present in descending order of prevalence were: Cooperia oncophora/Cooperia surnabada, Ostertagia leptospicularis/Ostertagia kolchida, Oesophagostomum venulosum, Bunostomum phlebotomum, Chabertia ovina, Nematodirus helvetianus, Trichostrongylus longispicularis, Haemonchus contortus and Aonchotheca bilobata. The cows from Bavaria and Tyrol harbored more total gastrointestinal nematodes than that from Saxony (geometric mean adult plus inhibited larval nematodes, 6510 vs. 2051, respectively). However, in both cohorts of cows abomasal nematodes accounted for ∼97% of the total nematode burden with inhibited larval Ostertagia species nematodes contributing over 70% of the total gastrointestinal nematode burden and∼96% of the Ostertagia species burden. Approximately 44%, 37% and 19% of the cows harbored <5000, 5000 to 10,000 or>10,000 total gastrointestinal nematodes, respectively. Fecal nematode egg and coproculture nematode larval counts significantly correlated with the cows' total adult nematode burden (rs=0.354, p<0.05, and rs=0.608, p<0.001, respectively). Although the magnitude of nematode burden to exert production effects on dairy cows is not well defined and may vary relative to several factors including nutritional supplementation, the level of mixed parasitism found in this investigation supports consideration of grazing dairy cows in helminth control measures, especially at the time of housing in autumn.

Anthelmintic Resistance Status in Gastrointestinal Nematodes of Seven Different Breeds of Sheep in intensive management

The severe use of anthelmintics to control gastrointestinal nematodes has become an essential issue in many countries, especially related to resistance issues. A study was carried out to determine the anthelmintic resistance status of intestinal nematodes of sheep, which were kept intensively in Bogor District, Indonesia. A total of 220 sheep of 7 breeds that routinely received Benzimidazole anthelmintics group to control gastrointestinal nematode were designated for this study. The animals were divided into 7 groups based on the breed and treated with Albendazole at the required dose. The Fecal Egg Count Reduction Test (FECRT) method was used to evaluate the anthelmintic’s effectiveness. The mean fecal egg count reduction was recorded at seven and fourteen days of treatment. The result indicated that 7 breeds of sheep were resistant to the anthelmintic used. Garut Local and Barbados Cross breeds showed relatively high resistance to Albendazole, with the mean fecal egg count at fourteen days of treatment being 60.24% and 67.97%, respectively. Haemonchus spp. larvae were the nematode larvae of strongyles species that grew the most in each breed of sheep from the fecal samples on day 0 (before treatment), day 7, and day 14 after treatment.

Angie-LAMP for diagnosis of human eosinophilic meningitis using dog as proxy: A LAMP assay for Angiostrongylus cantonensis DNA in cerebrospinal fluid

Angiostrongylus cantonensis (rat lungworm) is recognised as the leading cause of human eosinophilic meningitis, a serious condition observed when nematode larvae migrate through the CNS. Canine Neural Angiostrongyliasis (CNA) is the analogous disease in dogs. Both humans and dogs are accidental hosts, and a rapid diagnosis is warranted. A highly sensitive PCR based assay is available but often not readily accessible in many jurisdictions. An alternative DNA amplification assay that would further improve accessibility is needed. This study aimed to assess the diagnostic utility of a newly designed LAMP assay to detect DNA of globally distributed and invasive A. cantonensis and Angiostrongylus mackerrasae, the other neurotropic Angiostrongylus species, which is native to Australia. Cerebrospinal fluid (CSF) from dogs with a presumptive diagnosis of A. cantonensis infection (2020-2022) were received for confirmatory laboratory testing and processed for DNA isolation and ultrasensitive Angiostrongylus qPCR targeting AcanR3390. A newly designed LAMP assay targeting the same gene target was directly compared to the reference ultrasensitive qPCR in a diagnostic laboratory setting to determine the presence of A. cantonensis DNA to diagnose CNA. The LAMP assay (Angie-LAMP) allowed the sensitive detection of A. cantonensis DNA from archived DNA specimens (Kappa = 0.81, 95%CI 0.69-0.92; n = 93) and rapid single-step lysis of archived CSF samples (Kappa = 0.77, 95%CI 0.59-0.94; n = 52). Only A. cantonensis DNA was detected in canine CSF samples, and co-infection with A. mackerrasae using amplicon deep sequencing (ITS-2 rDNA) was not demonstrated. Both SYD.1 and AC13 haplotypes were detected using sequencing of partial cox1. The Angie-LAMP assay is a useful molecular tool for detecting Angiostrongylus DNA in canine CSF and performs comparably to a laboratory Angiostrongylus qPCR. Adaptation of single-step sample lysis improved potential applicability for diagnosis of angiostrongyliasis in a clinical setting for dogs and by extension, to humans.

Soil of periurban dwellings like scenario of development and/or infection of potentially zoonotic parasites in northeast of Argentina

In this research, soil contamination in household environment with soil-borne parasites species in dwellings of a periurban neighborhood and a shantytown in northeast of Argentina was described and associated with sanitary variables. Each house evaluated was considered as a unit of analysis. The samples were analyzed under three different techniques: centrifugal sedimentation; Willis Molloy flotation and flotation with Sheather's solution. Out of the 30 houses analyzed, 12 (40.0%) presented at least one parasitic forms in soil samples. We recorded three taxa, the most prevalent were nematodes larvae (related to hookworms), reported in the 30% of dwellings followed by Toxocara canis and Trichuris vulpis eggs and Cytoisospora canis oocyst in the 3,3% of houses. No statistical association was observed between soil contamination and the sanitary variables (p &gt; 0.05). These preliminary results demonstrate that domestic environment soil could represent a high potential for infection and re-infection for humans, principally young children and their pets.