New record of Philometra species from the marine edible fish Terapon jarbua collected from the Sindh, Arabian Sea, Pakistan.

Diseases in fish due to helminth parasites, especially Philometra species, are the primary worry in aquaculture. Philometra are responsible for health problem in fishes they directly affect fish growth and population parameters. A comprehensive survey was conducted involving the examination of the marine fish species Terapon jarbua, gathered from the coastal waters of Sindh, Pakistan In this research different Philometra species from marine fish Terapon jarbua during 2021 and 2022. Philometra nematodes, belonging to the family Philometridae, are common parasitic organisms inhabiting both marine and freshwater environments. Their prevalence, particularly when existing in high numbers within host organisms, can lead to severe and potentially lethal consequences. Employing light microscopy techniques, diverse species of Philometra were identified, including Philometra teraponi, P. jarbuai, P. arabiai, P. karachii, and P. awarii, localized primarily within the ovaries of the host fish. A total of 140 fish samples were examined and 76 were infected. The intensity of infected fish was 54.28%. The identification process encompassed meticulous analysis of crucial parameters, such as body size, esophagus length, positioning of the nerve ring, dimensions of the ventriculus, and ligament size. Intriguingly, the parasites were found in varying contexts; while some were free within the ovaries, others were embedded within tissues, inducing severe muscular dystrophy. This research presents novel findings of Philometra nematodes in the marine waters of Pakistan, extending their host and geographical distribution records. Future studies are needed to better evaluate and describe the dynamics and the epidemiology of Philometra infection in wild and cultured fish species.

Towards an in situ non-lethal rapid test to accurately detect the presence of the nematode parasite, Anguillicoloides crassus, in European eel, Anguilla anguilla.

Anguillicoloides crassus is an invasive nematode parasite of the critically endangered European eel, Anguilla anguilla, and possibly one of the primary drivers of eel population collapse, impacting many features of eel physiology and life history. Early detection of the parasite is vital to limit the spread of A. crassus, to assess its potential impact on spawning biomass. However accurate diagnosis of infection could only be achieved via necropsy. To support eel fisheries management we developed a rapid, non-lethal, minimally invasive and in situ DNA-based method to infer the presence of the parasite in the swim bladder. Screening of 131 wild eels was undertaken between 2017 and 2019 in Ireland and UK to validate the procedure. DNA extractions and PCR were conducted using both a Qiagen Stool kit and in situ using Whatman qualitative filter paper No1 and a miniPCR DNA Discovery-System™. Primers were specifically designed to target the cytochrome oxidase mtDNA gene region and in situ extraction and amplification takes approximately 3 h for up to 16 individuals. Our in-situ diagnostic procedure demonstrated positive predictive values at 96% and negative predictive values at 87% by comparison to necropsy data. Our method could be a valuable tool in the hands of fisheries managers to enable infection control and help protect this iconic but critically endangered species.

The impact of Anguillicoloides crassus (Nematoda) on European eel swimbladder: histopathology and relationship between neuroendocrine and immune cells.

The swimbladder functions as a hydrostatic organ in most bony fishes, including the European eel, Anguilla anguilla. Infection by the nematode Anguillicoloides crassus impairs swimbladder function, significantly compromising the success of the eel spawning migration. Swimbladders from 32 yellow eels taken from Lake Trasimeno (Central Italy) were analysed by histopathology- and electron microscopy-based techniques. Sixteen eels (50%) harboured A. crassus in their swimbladders and intensity of infection ranged from 2 to 17 adult nematodes per organ (6.9 ± 1.6, mean ± s.e.). Gross observations of heavily infected swimbladders showed opacity and histological analysis found a papillose aspect to the mucosa and hyperplasia of the lamina propria, muscularis mucosae and submucosa. Inflammation, haemorrhages, dilation of blood vessels and epithelial erosion were common in infected swimbladders. In the epithelium of parasitized swimbladders, many empty spaces and lack of apical junctional complexes were frequent among the gas gland cells. In heavily infected swimbladders, we observed hyperplasia, cellular swelling and abundant vacuolization in the apical portion of the gas gland cells. Numerous mast cells and several macrophage aggregates were noticed in the mucosal layer of infected swimbladders. We found more nervous and endocrine elements immunoreactive to a panel of six rabbit polyclonal antibodies in infected swimbladders compared to uninfected.

Encapsulation of Anguillicola crassus reduces the abundance of adult parasite stages in the European eel (Anguilla anguilla).

Encapsulation of the parasitic nematode Anguillicola crassus Kuwahara, Niimi & Hagaki is commonly observed in its native host, the Japanese eel (Anguilla japonica Temminck & Schlegel). Encapsulation has also been described in a novel host, the European eel (A. anguilla L.), and there is evidence that encapsulation frequency has increased since the introduction of A. crassus. We examined whether encapsulation of A. crassus provides an advantage to its novel host in Lake Müggelsee, NE Germany. We provide the first evidence that encapsulation was associated with reduced abundance of adult A. crassus. This pattern was consistent in samples taken 3 months apart. There was no influence of infection on the expression of the two metabolic genes studied, but the number of capsules was negatively correlated with the expression of two mhc II genes of the adaptive immune response, suggesting a reduced activation. Interestingly, eels that encapsulated A. crassus had higher abundances of two native parasites compared with non-encapsulating eels. We propose that the response of A. anguilla to infection by A. crassus may interfere with its reaction to other co-occurring parasites.

New records of Philometra pellucida (Jägerskiöld, 1893) (Nematoda: Philometridae) from the body cavity of Arothron mappa (Lesson) and Arothron nigropunctatus (Bloch et Schneider) reared in aquariums, with synonymisation of Philometra robusta Moravec, Möller et Heeger, 1992.

We encountered two cases of infection with large female nematodes of the genus Philometra Costa, 1845 in the body cavity of a map puffer Arothron mappa (Lesson) caught off Okinawa, Japan, and a blackspotted puffer Arothron nigropunctatus (Bloch et Schneider) caught off Queensland, Australia, both reared in aquariums in Japan. No morphological difference was observed between the nematodes from A. mappa and A. nigropunctatus. We identified the nematodes as Philometra pellucida (Jägerskiöld, 1893) based on their morphology. The sequences of the nematodes from both hosts were identical to each other (1,643 bp) and formed a clade with other 17 nematodes belonging to the genera Philometra and Philometroides Yamaguti, 1935 with high bootstrap value (bp = 100). It is the first time that the genetic data on P. pellucida are provided. Philometra robusta Moravec, Möller et Heeger, 1992 is synonymised with the former species.

New records of Philometra spp. (Nematoda: Philometridae) from marine perciform fishes off Florida, USA, including descriptions of two new species.

Recent examinations of marine perciform fishes from off the Florida coast in the Gulf of Mexico and Straits of Florida, USA, revealed the presence of the following six species of Philometra Costa, 1845 (Nematoda: Philometridae): P. haemulontis sp. n. (males and females) from the ovary of Haemulon plumierii (Lacepède) (type host) and H. aurolineatum Cuvier (both Haemulidae); Philometra synagridis Moravec, Bakenhaster et Fajer-Ávila, 2014 (males and females) from the ovary and testes of Lutjanus synagris (Linnaeus) (Lutjanidae); P. margolisi Moravec, Vidal-Martínez et Aguirre-Macedo, 1995 (male) from the ovary of Hyporthodus nigritus (Holbrook) (Serranidae) (new host record; probably a paradefinitive host); P. andersoni sp. n. (male) from the ovary of H. nigritus; Philometra sp. 1 (male) from the ovary of Rhomboplites aurorubens (Cuvier) (Lutjanidae); and Philometra sp. 2 (females) from the subcutaneous tissue of the anterior-most head sinuses of Hyporthodus niveatus (Valenciennes) (Serranidae). Specimens of species are described and illustrated based on light and (except for Philometra sp. 1) scanning electron microscopical examinations. Philometra haemulontis sp. n. differs from all congeners in the unique structure of the gubernaculum, whereas P. andersoni sp. n. can be differentiated from other gonad-infecting congeners parasitising the Serranidae by a combination of morphological features. Females of P. synagridis are described for the first time. Gravid females of Philometra sp. 2 are similar to those of P. morii Moravec, Bakenhaster et Fajer-Ávila, 2010, a subcutaneous parasite of Epinephelus morio (Valenciennes) (Serranidae) in the Gulf of Mexico.

Experimental infection with Anguillicola crassus alters immune gene expression in both spleen and head kidney of the European eel (Anguilla anguilla).

Invasive parasites have been implicated in the declines of several freshwater species. The swim bladder nematode Anguillicola crassus was introduced into Europe in the 1980s and is considered a threat to the European eel (Anguilla anguilla). Infection affects stress resistance and swimming behaviour. European eels produce an immune response against the parasite during the late stages of infection and after repeated infections. We used RNA-seq to examine the molecular response to infection during the poorly understood early stage and identify expression of genes and associated processes that are modified in two immune organs of European eels 3 days post infection with A. crassus. In the spleen, 67 genes were differentially expressed, 32 of which were annotated. Most of these were involved in immune processes and their regulation. Other differentially expressed genes in the spleen were important for heme metabolism and heme turn-over. In the head kidney, 257 genes (134 annotated) were differentially expressed. Several of these were associated with immune functions. Other differentially expressed genes in the head kidney were related to renal function, in particular osmoregulation and paracellular flow. We conclude that the early response of European eels to A. crassus is complex and involves various processes aside from the immune system. We identified molecular changes occurring early during the infection and identified candidate genes and processes which will facilitate future studies aimed at determining the factors affecting European eel viability in the face of this invasive parasite.

New records of philometrids (Nematoda: Philometridae) from marine fishes off Australia, including description of four new species and erection of Digitiphilometroides gen. n.

The following six species of the Philometridae (Nematoda: Dracunculoidea) were recorded from marine fishes off the northern coast of Australia in 2015 and 2016: Philometra arafurensis sp. n. and Philometra papillicaudata sp. n. from the ovary and the tissue behind the gills, respectively, of the emperor red snapper Lutjanus sebae (Cuvier); Philometra mawsonae sp. n. and Dentiphilometra malabarici sp. n. from the ovary and the tissue behind the gills, respectively, of the Malabar blood snapper Lutjanus malabaricus (Bloch et Schneider); Philometra sp. from the ovary of the goldbanded jobfish Pristipomoides multidens (Day) (Perciformes: all Lutjanidae); and Digitiphilometroides marinus (Moravec et de Buron, 2009) comb. n. from the body cavity of the cobia Rachycentron canadum (Linnaeus) (Perciformes: Rachycentridae). Digitiphilometroides gen. n. is established based on the presence of unique digital cuticular ornamentations on the female body. New gonad-infecting species, P. arafurensis and P. mawsonae, are characterised mainly by the length of spicules (252-264 µm and 351-435 µm, respectively) and the structure of the gubernaculum, whereas P. papillicaudata is characterised mainly by the body length (70 mm) of gravid female, extent of the oesophageal gland, size of caudal projections and the location in the host. Dentiphilometra malabarici differs from congeners mainly in the arrangement of circumoral teeth (in a single row), extent of the oesophageal gland and the absence of sclerotised teeth or protuberances on the oesophageal lobes in the mouth. Digitiphilometroides marinus has not previously been reported from fishes in Australian waters.

Transcript levels of members of the SLC2 and SLC5 families of glucose transport proteins in eel swimbladder tissue: the influence of silvering and the influence of a nematode infection.

The rate of glucose metabolism has been shown to be correlated to glucose uptake in swimbladder gas gland cells. Therefore, it is assumed that in the European eel silvering, i.e., the preparation of the eel for the spawning migration to the Sargasso Sea, coincides with an enhanced capacity for glucose uptake. To test this hypothesis expression of all known glucose transport proteins has been assessed at the transcript level in yellow and in silver eels, and we also included Anguillicola crassus infected swimbladders. Glucose uptake by rete mirabile endothelial cells could be crucial for the countercurrent exchange capacity of the rete. Therefore, this tissue was also included in our analysis. The results revealed expression of ten different members of the slc2 family of glucose transporters, of four slc5 family members, and of kiaa1919 in gas gland tissue. Glucose transporters of the slc2 family were expressed at very high level, and slc2a1b made up about 80% of all slc2 family members, irrespective of the developmental state or the infection status of the eel. Overall, the slc5 family contributed to only about 8% of all detected glucose transport transcripts in gas gland tissue, and the slc2 family to more than 85%. In rete capillaries, the contribution of sodium-dependent glucose transporters was significantly higher, leaving only 66% for the slc2 family of glucose transporters. Neither silvering nor the infection status had a significant effect on the expression of glucose transporters in swimbladder gas gland tissue, suggesting that glucose metabolism of eel gas gland cells may not be related to transcriptional changes of glucose transport proteins.

Anthropogenic spreading of anguillid herpesvirus 1 by stocking of infected farmed European eels, Anguilla anguilla (L.), in the Schlei fjord in northern Germany.

The Schlei fjord in northern Germany is the recipient water of a comprehensive eel, Anguilla anguilla (L.), stocking programme. Since 2015, stocked eels become alizarin red S marked, but to date no control mechanism is implemented in this stock enhancement measure to prevent anthropogenic spreading of diseases. Consequentially, it was possible that farmed stocking cohorts of 2015 and 2016 (in total ca. 1040 kg) were subsequently tested positive for anguillid herpesvirus 1 (AngHV 1). For this study, 100 eels [total length (TL) 24.3-72.9 cm, age ca. 1-6 years] were caught in 2016 and investigated with regard to AngHV 1 infection, parasite load (Anguillicoloides crassus) and body conditions. 68% of the eels were found to be virus positive while larger specimens were more often infected. In addition, a fitted generalized linear model (area under the curve = 0.741) demonstrated that an increase in individual TL is accompanied with an increased risk of clinically relevant virus loads. Anguillicoloides crassus turned out to be an important stressor for eels, because parasite and virus load revealed a significant positive correlation. The results of this study evidently show the urgent need of a disease containment strategy for eel stocking programmes.

The effect of foraging and ontogeny on the prevalence and intensity of the invasive parasite Anguillicola crassus in the European eel Anguilla anguilla.

Infection patterns of the invasive Anguillicola crassus nematode were investigated in a population of the European eel Anguilla anguilla where parasite invasion is very recent, Loch Lomond, Scotland. Intensity levels of the parasite were associated with differences in fish ontogeny and trophic ecology. Although eels foraged on both fish and invertebrates, individuals which were smaller and fed on invertebrates (>70% contribution to diet) were found to contain a greater number of swim bladder parasites compared to larger eel with a predominance of fish (>60% contribution) in their diet. Within affected fish, a significant negative relationship was found between fish length and parasite intensity, with smaller individuals having higher parasite intensity than larger individuals. This study indicates that food intake and infection risk are linked in this recently infected host-parasite system. From a management perspective increasing our understanding of how infection intensity and repeated exposure is linked to resource use in an ecosystem is important for the future management of this endangered species in Europe.

The Hsp70 response of Anguillicola species to host-specific stressors.

The present study is based on infection experiments of two different swim bladder parasite species, Anguillicola crassus Kuwahara et al., 1974 and Anguillicola novaezelandiae Moravec and Taraschewski, 1988, which were experimentally transferred to the two eel species Anguilla anguilla Linnaeus, 1758 and Anguilla japonica Temmink and Schlegel, 1846, respectively. The host-parasite groups were selected due to their different grades of mutual adaptation. The main aim of this study was to analyze the stress responses within the parasites, which were confronted with different hosts, i.e. with different stressors related to the respective host. For this purpose, mean intensities, recovery rates, larvae output, and levels of synthesized heat shock proteins (Hsp70) were determined in nematodes of each infection group. Increased stress responses were detected in the endemic system of A. crassus parasitizing A. japonica and A. crassus in its recently acquired host A. anguilla, which seems to be associated with the immune response of the particular host species and the expenditure of energy on producing larvae. A. novaezelandiae showed overall weak activities in its unknown host species A. japonica, with the lowest recovery rate of all examined groups neither featuring elevated Hsp responses, nor a high mean intensity, nor any reproductive output. On the contrary, in A. anguilla, the parasite reached higher recovery rates, mean intensities, and reproductive output, but no increased Hsp70 levels could be detected. The four considered factors proved partially interdependent, whereas few results did not follow a clear pattern.

A new species of philometrid parasite (Nematoda, Philometridae) and histopathological lesions in juvenile whitemouth croakers, Micropogonias furnieri (Desmarest).

A new species of nematode parasite, Philometroides tahieli sp. nov. is described. The juvenile whitemouth croaker, Micropogonias furnieri Desmarest, was collected during the spring and summer of the years 2008-2010 from estuarial environments of Argentina. During investigations of the parasite fauna a nematode encapsulated in the musculature of the operculum was found. The nematodes were removed from the host's muscle tissue and slide-mounted in lactophenol solution to clarify the specimens. Opercular muscle with the parasite was processed for histopathological examination. Philometroides tahieli sp. nov. can be identified by the location of gravid females in the host, presence of anterior oesophageal bulb, bosses on the surface of the body, presence of transversal mounds and 14 cephalic papillae in two circular rows. The pathogenicity of the parasite is low in the natural environment, but lesions are consistent with a chronic process. The appearance of caseous necrosis suggests the presence of a locally acting substance. Philometroides tahieli sp. nov. is the second species of this genera described from brackish waters, and since the discovery of Philometroides maplestoni in 1928, is the first species of this genus recorded for South America.

Avioserpens in the Western Grebe (Aechmophorus occidentalis): A new Host and Geographic Record for a Dracunculoid Nematode and Implications of Migration and Climate Change.

We report a new host and geographic range for the dracunculoid nematode (Avioserpens sp.) in a Western Grebe (Aechmophorus occidentalis) from southern Arizona, US. This discovery underscores the importance of parasite discovery and identification in the wildlife rehabilitation setting. Climate change and weather events affect the migratory spread of unusual parasites.

Comparative imaging of European eels (Anguilla anguilla) for the evaluation of swimbladder nematode (Anguillicoloides crassus) infestation.

This study compares diagnostic imaging tools in detecting the parasitic swimbladder nematode Anguillicoloides crassus in Anguilla anguilla (L.) and focuses on ultrasound in an attempt to develop a non-destructive, field diagnostic test. Ultrasound use could allow the parasite to be diagnosed without decreasing the number of critically endangered European eels through post-mortem. In the preliminary study, eels were examined with computed radiography, computed tomography, magnetic resonance imaging, 14 MHz high-end ultrasound and 5 MHz low-end portable ultrasound, and the results were compared with post-mortem findings. This ultrasound scanning technique did not produce any promising results. A second batch of eels was examined using the same high-end and low-end ultrasounds, but employing a different scanning technique and comparing the results with post-mortem. This second study, scanning along the midline from below, allowed for the detection of anomalies associated with moderately infected animals. None of the eels used in this study were severely infected; thus, no conclusions can be made regarding the use of ultrasound in those animals. Overall, it was found that none of the techniques were useful in diagnosing mildly infected individuals; therefore, no single diagnostic imaging tool is sensitive enough to replace post-mortem for definite diagnosis.

First Record of Paratenic Hosts of the Swimbladder Nematode Anguillicola crassus in North America.

Anguillicola crassus is a non-native parasite of the American eel, Anguilla rostrata. Since being introduced into North America, the nematode has spread rapidly across the range of A. rostrata, but paratenic hosts, which may facilitate parasite dispersion, have yet to be identified in the region. We investigated infection of larval A. crassus in 261 fish specimens belonging to 23 species and 12 orders collected from estuarine habitats in South Carolina (salinities 0-9 ppt) and Nova Scotia (10-18 ppt). A total of 35 fish belonging to 5 species and 3 orders were infected with the third-stage larvae (L3) of A. crassus, providing the first record of paratenic hosts for the parasite in North America. In South Carolina, high prevalence and abundance of the worm were found in spot (Leiostomus xanthurus), silver perch (Bairdiella chrysoura), and highfin goby (Gobionellus oceanicus), and a high prevalence but lower abundance was found in mummichog (Fundulus heteroclitus). In Nova Scotia, 2 nematodes were found in a single specimen of tomcod (Microgadus tomcod). All of the infected species are associated with a benthic lifestyle, and some of them are known to move between estuaries along the coastline. Lower infection rates in Nova Scotia may be associated with lower water temperatures and/or higher salinity of the sampling site. Most of the L3 were found encapsulated in mesenteric tissue around the intestine and stomach. No L4 or pre-adult worms were found. Mean body length of the L3 was smaller than L3 stages found in American eels from Cape Breton. This suggests that development of A. crassus is arrested at the L3 in the 5 fish species reported here, supporting their status as paratenic hosts.

Infection ecology of Philometra ovata (Nematoda: Philometridae) in a wild European minnow (Phoxinus phoxinus) population in Finland.

Seasonal life cycle of body cavity dwelling (BCD) Philometra ovata (Nematoda: Philometridae) has been reported in southern and central European countries, but its swim bladder dwelling (SBD) stage and northern populations have remained unstudied. In this study, we investigated the seasonal life cycle and infection ecology of P. ovata in both swim bladder and body cavity in the European minnow (Phoxinus phoxinus) in Finland. The larval P. ovata infected the swim bladder of minnows mainly in August. Female SBD P. ovata emigrated to body cavity mostly in September, grew to their full size by the end of the next June, and evacuated from minnows in July. In addition, female SBD P. ovata retarding their development and staying in swim bladder were found commonly in minnows, thus the mean monthly prevalence (6·7 ± 3·9%) and mean intensity (1·4 ± 0·8) of BCD P. ovata was lower than that of SBD P. ovata (37·8 ± 15·1% and 2·0 ± 1·5, respectively). Finally, despite the large size of BCD individuals, infection of P. ovata did not impair body condition and relative gonad size of minnows, but increased the mortality and caused physical damages in their hosts during the evacuation period.

Influence of adult Anguillicoloides crassus load in European eels swimbladder on macrophage response.

Anguillicoloides crassus has become one of the most important threats to the European eel (Anguilla anguilla). Adult parasites colonize the swimbladder leading to an impaired functioning of this organ. The infection is also responsible for an increased in the stress level of infected eels, that could produce an altered immune response as well. Differences in parasite loads and effects in the European and Japanese eel (Anguilla japonica) have been described. We have studied the influence of the number of adult parasites present in the swimbladder of wild eels on the macrophage response (phagocytosis and respiratory burst) as part of the first immune response to pathogens. Our results show an increased phagocytozed bacterial survival 24 h post-infection in macrophages of eels infected with more than ten adult parasites compared to macrophages from eels infected with less than those ten adult parasites. Respiratory burst results also showed a less efficient response in macrophages from eels infected with more than ten adult parasites, although in this case results were not found to be significant.

Two new gonad-infecting species of Philometra Costa, 1845 (Nematoda: Philometridae) from marine fishes off the northern coast of Australia.

Based on light and electron microscopical studies, two new gonad-infecting species of Philometra Costa, 1845 (Nematoda: Philometridae) are described from the ovary of marine perciform fishes off the northern coast of Australia (near Darwin): Philometra carangis n. sp. from the bluespotted trevally Caranx bucculentus Alleyne & Macleay (Carangidae) and P. carponotati n. sp. from the Spanish flag snapper Lutjanus carponotatus (Richardson) (Lutjanidae). Philometra carangis is mainly characterised by the length of the spicules (153-189 µm), the presence of a distinct dorsal protuberance consisting of two dorsolateral lamellar parts separated from each other by a smooth median field, a V-shaped mound on the male caudal extremity, a pair of large post-cloacal papillae and the body length of the males (3.22-4.15 mm). Philometra carponotati is distinguished from other congeneric species parasitising lutjanids by the length of the spicules and gubernaculum (225-252 and 99-117 µm, respectively), the absence of a dorsal protuberance on the distal lamellar part of the gubernaculum, the presence of a U-shaped mound on the male caudal extremity, a pair of large post-cloacal papillae and the body length of the male (3.74-4.31 mm). Besides the recently established Philometra zabidii Moravec & Diggles, 2014 (based on a single female), these two newly described nematodes are the only nominal gonad-infecting species of Philometra known to parasitise marine fishes in Australian waters.

Effects of Anguillicola novaezelandiae on the levels of cortisol and hsp70 in the European eel.

The nematodes Anguillicola novaezelandiae and Anguillicola crassus are both alien parasites of the European eel with severe adverse effects on their new host. Both species differ in terms of their invasiveness and their severity of harmful effects on the European eel. The purpose of this study was to determine under laboratory conditions whether stages of A. novaezelandiae induce stress in European eels (Anguilla anguilla) and if these levels differ from stress levels induced by A. crassus. We analysed levels of plasma cortisol and hepatic hsp70 of eels experimentally infected with A. novaezelandiae and compared them to uninfected eels as well as to eels experimentally infected with A. crassus. Larval stages of A. novaezelandiae induced higher levels of plasma cortisol compared to uninfected controls, while adult parasites increased the levels of hepatic hsp70 above those of uninfected controls. The eels' cortisol response is induced by larval stages of A. novaezelandiae, while adult stages elevate levels of hepatic hsp70. Levels of stress induced by A. novaezelandiae are comparable to those induced by A. crassus.