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To know the prevalence of gastrointestinal nematode larvae (L ) in the grazing land of cattle in Guwahati, Kamrup district, Assam. Pastures were collected and examined for the presence of nematode larvae (L ) from six localities of Guwahati at monthly interval from August 2012 to July 2013. The counted larvae were then expressed as per kg dry matter of herbage (L /kg DM). Examination of pastures revealed presence of nematode larvae (L ) in pastures throughout the year which varied from 4.5 L /kg DM in January to a maximum of 106.33 L /kg DM in August. The L of , spp., spp., spp., and spp. were recovered from pastures. The average pasture larval burden (PLB) was 34.75±3.48 L /kg DM. Season-wise PLB revealed the presence of 23.89±3.01, 67.54±5.41, 26.67±1.92, and 7.28±0.89 L /kg DM during pre-monsoon, monsoon, post-monsoon, and winter seasons, respectively. Monsoon season has significant (p<0.05) effect on PLB. However, analysis of variance of different locations with respect to season revealed that there was no significant difference but season-wise it was highly significant (p<0.01). Pearson correlation of environmental variables (temperature, relative humidity, and rainfall) with PLB revealed correlation was statistically significant with rainfall (p<0.05). This study reveals the presence of five nematode larvae (L ) in the pastures of Guwahati, Assam throughout the year, statistically significant during monsoon season.

Anisakis spp. L3 larvae commonly found in marine fish species are an important biological hazard when raw or inadequately thermally processed fishery products are consumed with live larvae, highlighting the need for effective control strategies. This study evaluated the efficacy and mechanism of photodynamic inactivation (PDI) of Anisakis L3 larvae, using the cationic photosensitizer (PS) 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin tetraiodide (TMPyP). Larvae were collected from Atlantic horse mackerel and grouped by size: batch A (larvae ≈ 1.5 cm) and batch B (larvae ≈ 2.0 cm). Inactivation assays were performed in microcosms at 50 µM of TMPyP under different conditions: incubation times (15 min to 21 h); incubation temperatures (0.5 and 22 °C); irradiation period (2–8 h) and light irradiance (4, 14 and 67 mW/cm 2 ). Viability and tissue damage of the larvae were assessed at post-treatment. In both batches, 100% of larvae mortality was achieved after 21 h of dark incubation at 22 °C with TMPyP, followed by 6–8 h of white light irradiation at 67 mW/cm 2 . Similar results were observed in batch B, when the dark incubation was performed at 0.5 °C. Notably, batch B, larvae showed more exuberant cytotoxic effect, including severe damage of the intestinal epithelium, leading to loss of the characteristic triradiate appearance. These findings indicate that PDI using TMPyP is effective in inactivating Anisakis larvae and could be a potential alternative to freezing for ensuring the safety of fishery products in the food industry.

Gastrointestinal nematodes (GIN) use flexible life history strategies to maintain their fitness under environmental challenges. Costs incurred by a challenge to one life trait can be recouped by increasing the expression of subsequent life traits throughout their life cycle. Anticipating how parasites respond to the challenge of control interventions is critical for the long-term sustainability of the practice and to further ensure that the parasites withstand favourable adaptive responses. There is currently limited information on whether distinct populations of a GIN species respond to the same environmental challenge in a consistent manner, with similar alterations to their life history strategies or comparable fitness outcomes. This study compared the life history traits and experimental fitness of three distinct Haemonchus contortus isolates exposed to environmental challenges at both the parasitic (i.e., passage through resistant or susceptible sheep) and free-living (i.e., exposure to diverse climatic conditions) life stages. The key findings show that H. contortus maintain their fitness under challenge with isolate-specific alterations to their life history strategies. Further, partial exploration of the H. contortus isolates transcriptomes using cDNA-AFLP methods confirmed disparate expression profiles between them. These results bring fresh insights into our understanding of the non-genetic adaptive processes of GIN that may hinder the efficacy of parasite control strategies.

Several species of saprophytic filamentous fungi are able of disrupting the life cycle of certain soil-born parasites that are of veterinary and agronomy importance, offering a promising sustainable control alternative. This study consisted of designing an experimental model, using catnip (Nepeta cataria) trays to simulate a vegetated environment for evaluating the parasiticidal activity of Mucor circinelloides, Trichoderma atrobrunneum, and Duddingtonia flagrans. Fungal spores were added to treated trays before adding feces with protozoan (Eimeria spp.), and gastrointestinal nematodes (roundworms, strongyles), and untreated-control water. No differences in plant growth or vigor, regardless of fungal presence, were observed, confirming the safety of these biological agents for vegetation. In the control trays, the viability of parasites ranged from 50% to 85%. In the treated trays, the viability of Eimeria and roundworms decreased by 40–100%, and the strongyle egg counts were reduced by 74% within 15 days. It is concluded that the vegetated tray model effectively simulates field conditions and provides a reliable platform for evaluating fungal efficacy against the free-living stages of parasites, offering a versatile tool for future research on soil-borne pathogens affecting animals and plants.

The aim of this experiment was to determine the yield of Haemonchus contortus third-stage larvae (L3) in faecal cultures in different conditions, including incubation time (7 or 14 days), the addition of inert additives (polystyrene pellets, vermiculite or no additive) and physical condition of the incubated faeces (ground or whole pellets). Twelve groups of 10 cultures each were arranged and incubated at 24 °C to evaluate the interaction of the above-mentioned conditions. Significantly, more L3 (p=0.0019 to p=0.0200) were recovered from cultures incubated for 7 days than for 14 days, except for the groups containing whole pellets with no additives (p=0.53) or with vermiculite (p=0.41). Larval yields from 7-day incubated cultures did not differ between groups (p=0.47), but for the whole pellets with vermiculite group, which yielded significantly less L3 (p<0.0001) than the rest of the cultures. Incubation for 14 days showed that cultures containing whole pellets with no additives yielded significantly more L3 (p<0.05) than the rest. Culturing faeces with H. contortus seems not to require inert additives or extra manipulation to obtain good L3 yields.

The original host of the swimbladder nematode Anguillicola crassus, the Japanese eel (Anguilla japonica) and the recently colonized European eel (Anguilla anguilla) were immunized with 40 irradiated (500 Gy) 3rd-stage larvae (L3) of this parasite and challenged with an infection of 40 normal L3. The immunization induced a significant reduction of the number of adult worms developing from the challenge infection in A. japonica, but not in A. anguilla. The induced resistance (calculated using the relation of the number of adult worms in immunized eels and in non-immunized control eels) in A. japonica was 87·3%±30·4%. Following a single infection, the percentage of adult worms found in A. japonica was lower as compared to A. anguilla, and the few adult worms were much smaller, revealing a lower susceptibility of A. japonica to A. crassus in comparison to A. anguilla. Both eel species developed an antibody response against A. crassus, but the level of antibody responses was not positively correlated with the protection against infection, suggesting that the antibody response is not a key element in resistance of eels against A. crassus. This study suggests that the original host of A. crassus is able to mount efficient protective immune responses against its parasite, whereas the newly acquired host seems to lack this ability.

BACKGROUND: Ashworthius sidemi, a blood-sucking nematode, is a primary parasite of Asiatic cervides, primarily sika deer (Cervus nippon). As A. sidemi infections are common in bison, red and roe deer, and gastrointestinal nematodes are often exchanged between animals, it is possible that other farm animals such as cows and sheep that may use the same pastures can be infected. Hence, histopathological changes observed in the walls of the abomasa and duodena of infected wildlife caused by a strong parasite presence may become an important health problem also for farm animals. METHODS: In the present study, a simple PCR test for the detection of A. sidemi infection in European bison based on DNA from third stage infective larvae (L3) has been optimized. RESULTS: The species-specific primers generated a 406 bp fragment, and A. sidemi DNA could be detected at concentrations of 0.1 pg/μl. The specificity of PCR was confirmed by the use of the genomic DNA of adult Ostertagia ostertagi, Haemonchus contortus, Cooperiaoncophora as negative controls. CONCLUSION: It is possible to detect A. sidemi infection in European bison using DNA from L3. If this nematode infection is transmitted to cows this method may be effective to diagnose invasion in breeding animals in vivo.

The third larval stage (L3) of Anisakis simplex (Anisakidae) is one of the zoonotic parasitic nematodes in the musculature and visceral organs of marine fishes belonging to family Moronidae. The consumption of these high-commercial-value fish is widespread in many countries around the Mediterranean Sea including Egypt. The presence of these larvae in fish muscles poses a potential consumer hazard due to the parasite’s ability to cause anisakidosis. Forty-two out of 60 (70 %) of the European seabass Dicentrarchus labrax were found to be naturally infected by L3 of A. simplex in the form of encapsulated juveniles in the fish musculature. Morphological examination of recovered parasites by light and scanning electron microscopy showed that, in general, all specimens examined closely resembled A. simplex (L3). To evaluate the allergenicity of this nematode, white blood cell count; levels of T helper 1 (Th1) [interferon (IFN)-γ and tumor necrosis factor (TNF)-α)], Th2 [IL-4, IL-5, and IL-6], and Th17 [IL-17] related cytokines; total IgE and IgG antibodies; and nitric oxide (NO) were measured in the plasma of Wistar rats sensitized by oral inoculation with fresh, frozen, and heat-treated A. simplex L3 or rats intraperitoneally injected with L3 crude extract. Rats sensitized with fresh and frozen L3 larvae produced significantly higher levels of IFN-γ, IL-5, IL-17, and total IgE as compared to control rats. Heat-treated larvae administration resulted in a significant rise of IFN-γ, TNF-α, IL-5, and total IgE in comparison to control rats. Intraperitoneal sensitizations enhanced release of IFN-γ, TNF-α, and total IgE. Oral sensitization led to a significant production of NO. Thereby, frozen or cooked larval L3 cannot inhibit the release of Th-related cytokines and IgE, which might impact on the overall anti-parasitic immunity.