Encapsulated Larvae Research Articles

Efficacy of silver nanoparticles against Trichinella spiralis in mice and the role of multivitamin in alleviating its toxicity

Trichinellosis is a worldwide zoonotic disease. The majority of currently available anti-trichinellosis medications exhibit inadequate efficacy. The efficacy of a natively prepared new formulation of silver nanoparticles (Ag-NPs) was evaluated in the treatment of Trichinella spiralis (T. spiralis) infection in mice alone and combined with multivitamin-mineral (MM). After investigating the product’s biological and pharmacological characteristics, its therapeutic dose was estimated to be Ag-NPs at 21.5 mg/kg B.W. This dose was orally inoculated to experimentally infected mice at 3–5 days post-inoculation (dpi) against the mature worms, at 8–10 dpi against the newborn larvae, and at 33–35th dpi against the encapsulated larvae. Each treatment’s efficacy was assessed by scarifying control and treated mice 3 days post-treatment. The drug alone or in supplement form has a high trichinocidal effect exceeding that of the reference drug. Early treatment (3–5 dpi) by Ag-NPs or Ag-NPs + MM and albendazole revealed high efficacy against the intestinal stage, reaching 93.3%, 94.7%, and 90.6% for the three treatments, respectively. The materials causing a significant (P-value < 0.001) decrease in the mean encapsulated larvae reached 86.61%, 89.07%, and 88.84%/gm of muscles using the three treatments, respectively. Moreover, all larvae extracted from Ag-NPs-treated groups failed to induce infection post-inoculation in new mice. Additionally, combining the material with MM proved to overcome the reversible adverse effects of silver material on the estimated redox parameters and liver and kidney biomarkers, denoting its ability to alleviate Ag-NP toxicity. In conclusion, the high trichinocidal effect of Ag-NPs against the adult and encapsulated larvae during a short inoculation period introduced Ag-NPs as an alternative to other nematicidal drugs.

A STUDY OF IMMUNOTHERAPEUTIC EFFICACY OF TRICHINELLA SPIRALIS EXCRETORY-SECRETORY PROTEINS IN MURINE TRICHINELLOSIS

Trichinellosis is a serious zoonotic parasitic and globally endemic disease. Benzimidazole derivativesare apparently unable to kill encapsulated larvae and its effectiveness depends on solubility, dosage oftherapy, host biotransformation, selectivity patterns as well as onset of treatment after infection. Excretory-secretory (ES) proteins released by Trichinella induce a strong immune response when tested as avaccine. The current study investigated both therapeutic and protective effects of adult worm excretorysecretory protein (AW/ES), or larval excretory secretory protein (LES) on T. spiralis infected mice,conducted by parasitological, histopathological, immunohistochemical, serological and molecular investigations.Larval excretory secretory protein achieved more significant therapeutic and protectiveeffects than adult worm excretory secretory protein in experimentally infected mice, causing reductionin larval counts and decrease in pathological changes of both muscular and intestinal tissues. It increasedserum IgG OD values, decreased Foxp3 expressions and increased the mean cycle thres- holdvalues of muscular tissues but it had lesser effects on adult worm counts than albendazole.

The parasite community of the sharks Galeus melastomus, Etmopterus spinax and Centroscymnus coelolepis from the NW Mediterranean deep-sea in relation to feeding ecology and health condition of the host and environmental gradients and variables

The parasite communities of sharks have been largely neglected despite the ecological importance and vulnerability of this group of fishes. The main goal of the present study is to describe the parasite communities of three deep-dwelling shark species in the NW Mediterranean. A total of 120 specimens of Galeus melastomus, 11 Etmopterus spinax and 10 Centroscymnus coelolepis were captured at 400–2200m depth at two seasons and three localities off the mainland and insular slopes of the Balearic Sea. Environmental and fish biological, parasitological, dietary, enzymatic and histological data were obtained for each specimen, and the relationships among them tested. For G. melastomus, E. spinax and C. coelolepis a total of 15, two and eight parasite species were respectively recovered. The parasite community of G. melastomus is characterized by high abundance, richness and diversity, and the cestodes Ditrachybothridium macrocephalum and Grillotia adenoplusia dominate the infracommunities of juvenile and adult specimens, respectively. A differentiation of parasite communities, linked to a diet shift, has been observed between ontogenic stages of this species. E. spinax displays a depauperate parasite community, and that of C. coelolepis, described for the first time, shows moderate richness and diversity. Detailed parasite-prey relationships have been discussed and possible transmission pathways suggested for the three hosts. Parasites were mostly related to high water turbidity and O2 levels, which enhance zooplankton proliferation and could thus enhance parasite transmission. The nematodes Hysterothylacium aduncum and Proleptus obtusus were linked to high salinity levels, as already reported by previous studies, which are associated to high biomass and diversity of benthic and benthopelagic crustaceans. A decrease of acetylcholinesterase activity and lower hepatosomatic index, possibly linked to infection-related stress, have been observed. Lesions associated to encapsulated larvae of G. adenoplusia have been observed in the muscle of G. melastomus, especially in the tail region, which can be indicative of the hunting strategy of its final host and may compromise the escape response of G. melatomus thus facilitating parasite transmission.

How did phytoplankton-feeding larvae re-evolve within muricid gastropods? A view from developmental morphology

Post-Paleozoic life history transitions in mollusks and echinoderms have been biased toward switches from feeding, planktonic larvae (planktotrophic), to one of the non-feeding developmental modes, such as maternally provisioned planktonic larvae, fully encapsulated larvae, or direct development. Nevertheless, rare resurrections of feeding larvae from fully encapsulated larvae have occurred within calyptraeid and muricid gastropods. The only previous study on the developing foregut of a muricid with encapsulated larvae (Nucella lapillus) indicated loss of the larval esophagus, a potential barrier to evolutionary re-emergence of larval planktotrophy. However, histological and ultrastructural examination of foregut development in two other nucellids, Nucella lamellosa and N. ostrina, both with fully encapsulated development, revealed a transient larval esophagus in both, as identified by anatomical position, tissue composition, interconnections to other structures, and fate at metamorphosis. The larval esophagus is difficult to recognize in nucellids without a comparative framework and a complete developmental series extending from early veliger stages through to juveniles. Both the larval mouth and distal larval esophagus are completely destroyed at metamorphosis. Surprisingly, encapsulated larvae of N. lamellosa also developed all three velar ciliary tracts needed for capture and ingestion of particles, despite absence of nurse egg feeding by encapsulated larvae of this species and despite apparent absence of phytoplankton-feeding larvae in this genus since its origin 20 million years ago. Retention of a larval esophagus and a full complement of velar ciliary tracts needed for particle capture and ingestion in encapsulated larvae of some muricids may help explain how larval planktotrophy re-emerged within this clade.

Prevalence and Molecular Characterization of Anisakidosis in both European (Merluccius merluccius) and Lizard Head (Saurida undosquamis) Hakes

AbstractThis study focuses on Anisakidosis as a disease caused by a number of Anisakid larvae including Anisakis simplex, Pseudoterranova decipiens, Hysterothylacium spp. and Contracaecum spp., through assessing the clinical signs and the clinical examination of the disease in 170 Lizard head (Saurida undosquamis) and 160 European hakes (Merluccius merluccius) during the period from April 2011 to July 2012. In addition, identification of the recovered larvae morphologically and using random modified polymorphic DNA (RAPD-PCR) technique. No obvious clinical signs were observed in the examined fish. The post mortem examination revealed the presence of free or encapsulated larvae within the body cavity, on the visceral organs and in the musculature. The seasonal prevalence of Anisakid larvae was the highest in spring and summer and its lowest level was in autumn in both examined fish spp. The highest intensity of larvae was observed in the organs and viscera rather than in the musculature. RAPD technique identified the recovered larvae using four arbitrary primers. It could be concluded that Anisakid larvae can be easily identified using molecular tools by its well characterized genetic finger print and that in turn will help in its diagnosis in parallel with the traditional tools.

Ocean acidification impairs vermetid reef recruitment

Vermetids form reefs in sub-tropical and warm-temperate waters that protect coasts from erosion, regulate sediment transport and accumulation, serve as carbon sinks and provide habitat for other species. The gastropods that form these reefs brood encapsulated larvae; they are threatened by rapid environmental changes since their ability to disperse is very limited. We used transplant experiments along a natural CO2 gradient to assess ocean acidification effects on the reef-building gastropod Dendropoma petraeum. We found that although D. petraeum were able to reproduce and brood at elevated levels of CO2, recruitment success was adversely affected. Long-term exposure to acidified conditions predicted for the year 2100 and beyond caused shell dissolution and a significant increase in shell Mg content. Unless CO2 emissions are reduced and conservation measures taken, our results suggest these reefs are in danger of extinction within this century, with significant ecological and socioeconomic ramifications for coastal systems.

Growth and survival of blue swimming crab (&amp;lt;i&amp;gt;Portunus pelagicus&amp;lt;/i&amp;gt;) reared on frozen and artificial foods

Experiments were conducted to evaluate the efficacy of two frozen organism (with and without instant Nannochloropsis oculata and with and without instant encapsulated Spirulina) and artificial diet (with and without artificial encapsulated shrimp larvae feed) with live food as continues feed in the larval rearing of blue swimming crab, Portunus pelagicus. The larvae were conducted with six treatments and each treatment with three replications on newly one day hatched larvae in each replication. Results showed that these larvae fed with a combination diet of instant frozen N. oculata, Artemia nauplii and rotifer give a higher survival rate till 1st day juvenile crab compared to the treatment with instant encapsulated Spirulina and artificial diet (with artificial encapsulated shrimp larvae feed). One of experiments treated with encapsulated Spirulina recorded only 16 days for the zoea to reach the C1, one day earlier as compared to previous trials treated with and without instant frozen N. oculata. One of the experiments treated with artificial encapsulated shrimp larvae feed recorded 18 days for the zoea to reach the C1, 1 to 2 days longer as compared to all the previous trials earlier. Food type influenced survival, development, and metamorphosis to megalopa and 1st day juvenile crab of P. pelagicus zoea larvae. Our findings illustrate that the best survival, the most rapid development and the highest number of 1st day juvenile crabs were obtained from larvae fed with a combination diet of frozen N. oculata, Artemia nauplii and rotifer from hatching till the 1st day juvenile crab.

Comparative Efficacy of Ivermectin and Levamisole for Reduction of Migrating and Encapsulated Larvae ofBaylisascaris transfugain Mice

The comparative efficacy of 2 anthelmintics (ivermectin and levamisole) against Baylisascaris transfuga migrating and encapsulated larvae was studied in mice. A total of 60 BALB/c mice inoculated each with about 1,000 embryonated B. transfuga eggs were equally divided into 6 groups (A-F) randomly. Mice of groups A and B were treated with ivermectin and levamisole, respectively, on day 3 post-infection (PI). Mice of groups A-C were killed on day 13 PI. Similarly, groups D and E were treated with ivermectin and levamisole, respectively, on day 14 PI, and all mice of groups D-F were treated on day 24 PI. The groups C and F were controls. Microexamination was conducted to count the larvae recovering from each mouse. The percentages of reduction in the number of migrating larvae recovered from group A (ivermectin) and B (levamisole) were 88.3% and 81.1%, respectively. In addition, the reduction in encapsulated larvae counts achieved by ivermectin (group D) and levamisole (group E) was 75.0% and 49.2%, respectively. The results suggested that, to a certain extent, both anthelmintics appeared to be more effective against migrating larvae than encapsulated larvae. However, in the incipient stage of infection, ivermectin may be more competent than levamisole as a larvicidal drug for B. transfuga.

2,4-Decadienal: Exploring a novel approach for the control of polychaete pests on cultured abalone

Infestations by shell-boring polychaete worms represent a threat to the continued growth of the abalone culture industry. The South African cultivated abalone, Haliotis midae, is affected by 3 species; the spionids Boccardia proboscidea and Polydora hoplura and the sabellid, Terebrasabella heterouncinata. Currently there are no effective treatments that do not cause undue harm to the abalone host while proving effective against the worms. Here we report on the efficacy of the diatom-derived polyunsaturated aldehyde 2,4-decadienal as a potential chemotherapeutic agent against shell-infesting polychaetes. Exposure to decadienal had pronounced dose- and time-dependent negative effects on larval mortality, growth and developmental rate. There was a variation in the response to treatment in relation to larval strategy, with planktotrophic B. proboscidea larvae more susceptible than adelphophagic larvae, and species, with lecithotrophic T. heterouncinata generally more sensitive than planktotrophic B. proboscidea larvae. Emergent larvae were more susceptible than encapsulated larvae. The egg capsule appears to provide an effective barrier to decadienal exposure. Decadienal could therefore prove effective as a control agent at several life history stages by reducing the number of larvae that survive and are able to settle, and also the fitness of the larvae that do survive and settle.

Anisakid Larvae in Atlantic Salmon (Salmo salar L.) Grilse and Post-Smolts: Molecular Identification and Histopathology

The molecular identification and histopathology are described for the parasitic larvae of a nematode species present in the abdominal cavity of Atlantic salmon ( Salmo salar ) grilse caught in fish traps on their natal river in the west of Ireland and post-smolts collected during experimental trawls on the continental shelf edge of the northeast Atlantic Ocean. Larvae in the adult and juvenile salmon were identified as Anisakis simplex sensu stricto by PCR amplification and RFLP and sequencing of the ITS gene and PCR amplification and sequencing of the cox2 gene. Parasitic nematode larvae in the grilse were either encapsulated in the abdominal mesentery associated with the pyloric ceca or on the serosal surface of the liver and in the vent region. In some fish, larvae were found in the parenchyma of the liver and muscularis circularis of the intestine. In general, the larvae induced a limited cellular response apart from the occurrence of focal melanin macrophage aggregates and individual eosinophilic granular cells in the connective tissue capsule. Melanin macrophage aggregates were also present among the hepatocytes adjacent to encapsulated larvae in the liver. The reaction to the parasites was more severe in the wall of the intestine. Encapsulated nematode larvae caused displacement, vacuolation, and necrosis of the circular muscle fibers. The stratum compactum was also disrupted with focal areas of degeneration. Overall, the intestinal wall had a hypercellular appearance with extensive cellular infiltration comprising eosinophilic granular cells, macrophages, lymphocytes, and fibrocytes. The post-smolts were caught in May during the early oceanic phase of their life cycle. In these fish, A. simplex sensu stricto larvae were found lying free on the serosal surface of the intestine and liver without any apparent histologic changes. This is the earliest in the marine migration of Atlantic salmon that A. simplex sensu stricto infection has been recorded.

Dynamics of hepatic stellate cells, collagen types I and III synthesis and gene expression of selected cytokines during hepatic fibrogenesis following Mesocestoides vogae (Cestoda) infection in mice

In the present study, the relationship between progression of Mesocestoides vogae infection in the liver of mice, the accumulation rate of collagen types I and III, gene expression of fibrogenic factors and cytokines was examined within 6weeks p.i. Due to asexual multiplication, the total number of larvae in the liver increased considerably and 63.4% were found in collagen capsules on day 42 p.i. Intense staining for both collagens was recorded in the activated hepatic stellate cells (HSCs) throughout the period of this study in the inflammatory lesions. With progressing infection, cellular expression of both collagens was confined to the flat cells, myofibroblasts, which were scattered among collagen fibres in parenchymal lesions and capsules. Collagen-positive areas mirrored immunostaining of α-smooth muscle actin (α-SMA) in HSCs and myofibroblasts. Gene expression of both collagens increased rapidly within 14days p.i. and their expression pattern resembled that for pro-fibrotic cytokine transforming growth factor (TGF)-β1 and α-SMA protein. IL-10 cytokine expression was up-regulated following day 14 p.i. and that of IL-13 was up-regulated early p.i., then transcription elevated gradually mirroring the activity of other pro-fibrotic markers. In contrast, transcription activity of TNF-α and IFN-γ was elevated shortly after infection, followed by the partial down-regulation of gene expression, indicating the lack of larval killing, enhanced granulomatous inflammation and the perpetuation of hepatic fibrosis. Histomorphometric analysis of the parenchymal fibrous lesions, surface areas of larvae surrounded with the inflammatory infiltrates and surface areas of developing or mature larva-containing granulomas, correlated with the proportion of free and encapsulated larvae, immunostaining and gene expression patterns of collagens and pro-fibrotic markers. At a later stage of infection (day 28 p.i. onwards) collagen I-positive areas occupied a greater surface area and formed mature larval capsules and scars in the liver. In contrast, collagen III was less abundant and was localised mainly in the fibrous lesions in damaged parenchyma, suggesting their specific up-regulation as the part of host-protecting and tissue-healing responses.

Comparison of the effects of Artemisia vulgaris and Artemisia absinthium growing in western Anatolia against trichinellosis (Trichinella spiralis) in rats

Trichinellosis often causing diarrhea and more rarely fever, periorbital edema and myositis in human, is commonly treated with benzimidazole derivatives. The Artemisia genus has been found to be effective against a variety of parasites. In the present study, the efficacy against trichinellosis (Trichinella spiralis) of Artemisia vulgaris and Artemisia absinthium was examined for the first time in rats. The results of trichinoscopy and artificial digestion, during the enteral (adult) phase of the illness show that 300mg/kg doses of methanol extracts of the aerial parts of A. vulgaris and A. absinthium reduced the larval rate by 75.6% and 63.5% in tongue, 53.4% and 37.7% in diaphragm, 67.8% and 46.2% in quadriceps, and 66.7% and 60.5% in biceps–triceps muscles of rats, respectively. Furthermore, during the parenteral (encapsulated larvae) phase, 600mg/kg doses of A. vulgaris and A. absinthium extracts decreased the larval rate by 66.4% and 59.9% in tongue, 57.4% and 50.0% in diaphragm, 47.6% and 43.7% in quadriceps, 60.2% and 46.4% in biceps–triceps muscles of rats, respectively. Analysis of antibody also showed that A. vulgaris significantly reduced the antibody response (P<0.05) during the enteral and parenteral phases. Thus, the results of the present study revealed that A. vulgaris could be an alternative drug against trichinellosis.

Unusual source of food: impact of dead siblings on encapsulated embryo development of Crepipatella fecunda (Gastropoda : Calyptraeidae)

Embryonic cannibalism has been identified in directly developing calyptraeid species through observation of the ingestion of encapsulated sibling embryos. The object of the present study was to determine the effects of experimentally induced cannibalism on larval development in encapsulated larvae of Crepipatella fecunda (a species having mixed development). The effects studied included the time of intracapsular development, protoconch size and velar characteristics of the larvae. Mortality was induced during intracapsular development through mechanical disruption (‘treatment’) of embryos. A treatment and control group of embryos from the same female were compared. Encapsulated veligers actively fed on their sacrificed congeners. Larvae hatched in less than 10 days from treated capsules and had mean shell lengths and velum areas significantly lower than those from the control, but no significant differences in cilia length. In treated capsules where the embryos underwent a slow development (&gt;20 days), the larvae produced shells, vela and cilia larger than those of the controls. In an intermediate period of intracapsular development, the differences recorded among larval characters were not statistically significant. The results showed that: (1) the encapsulated veligers were capable of feeding on exogenous food before hatching; (2) the consumption of non-living congeners decreased the time of intracapsular development; and (3) the morphometry of the larvae hatching from treated capsules varied depending on the period of intracapsular development and seems to be adaptively stabilised towards homogeneous larval morphometry.

Apical sensory neurones mediate developmental retardation induced by conspecific environmental stimuli in freshwater pulmonate snails.

Freshwater pond snails Helisoma trivolvis and Lymnaea stagnalis undergo larval development and metamorphosis inside egg capsules. We report that their development is permanently under slight tonic inhibitory influence of the anterior sensory monoaminergic neurones, which are the remnants of the apical sensory organ. Conspecific juvenile snails, when reared under conditions of starvation and crowding, release chemical signals that are detected by these neurones in encapsulated larvae and reversibly suppress larval development, thus providing a link between environmental signals and developmental regulation. Induced retardation starts from the trochophore stage and results in up to twofold prolongation of the larval lifespan. Upon stimulation with the signal, the neurones increase synthesis and release of monoamines [serotonin (5-HT) in Helisoma and dopamine in Lymnaea] that inhibit larval development acting via ergometrine-sensitive internal receptors. Thus, the novel regulatory mechanism in larval development of molluscs is suggested and compared with the phenomenon of dauer larvae formation in the nematode Caenorhabditis elegans.

Barium and strontium uptake into larval protoconchs and statoliths of the marine neogastropod Kelletia kelletii

The trace elemental composition of calcified larval hard parts may serve as useful tags of natal origin for invertebrate population studies. We examine whether the trace metal barium (Ba) deposits into the calcium carbonate matrix of molluscan larval statolith and protoconch in proportion to seawater Ba concentration at two temperatures (11.5 and 17°C). We also examine strontium (Sr) uptake as a function of temperature. Using encapsulated larvae of the marine gastropod, Kelletia kelletii, reared in the laboratory under controlled conditions, we demonstrate a significant inverse effect of temperature and a positive effect of seawater Ba/Ca ratio on Ba incorporation into larval carbonates. Ba/Ca partition coefficients ( D Ba ) in protoconch were 1.13 at 11.4°C and 0.88 at 17.1°C, while D Ba in larval statolith measured 1.58 at 11.4°C and 1.29 at 17.1°C. Strontium incorporation into statoliths is also inversely affected by temperature, but there was a significant positive effect of temperature on Sr incorporation into protoconch. These data suggest larval statoliths and protoconchs can meaningfully record variation in seawater physical and chemical properties, and, hence, have potential as natural tags of natal origin.

Metazoan parasites of flounder Platichthys flesus (L.) along a transect from the southwestern to the northeastern Baltic Sea

In connection with the BMB/ICES Sea-going Workshop “Fish Diseases and Parasites in the Baltic Sea”, 200 specimens of flounder Platichthys flesus from eight stations (25 from each) distributed from the southwestern (Mecklenburg Bight) to the northeastern Baltic Sea (Gulf of Finland) were examined for metazoan parasites. A few species (e.g. Hysterothylacium aduncum, Cucullanus heterochrous, Cucullanellus minutus, and Pomphorhynchus laevis) were found at virtually all stations. Typical “marine” species (Podocotyle atomon, Brachyphallus crenatus, Anisakis simplex, Holobomolochus confusus, and Lernaeocera branchialis) were found at the western stations only, whereas the metacercariae of Diplostomum spathaceum, and Cotylurus sp., immature Corynosoma sp., the larvae of Raphidascaris acus and Contracaecum osculatum were most common towards the east and north. Echinorhynchus gadi only occurred at the western and southern stations. The small encapsulated larvae of the bird nematodes Contracaecum sp., Paracuaria sp., and Cosmocephalus sp. were found at most stations. The effects of salinity on the patterns observed in relation to the distribution of intermediate and final hosts are discussed.

Discovery of mammalian hosts to Gnathostoma nipponicum larvae and prevalence of the larvae in rodents and insectivores.

From September 1993 to November 1995, to clarify the natural infection of Gnathostoma nipponicum (G.n.) larvae in small wild mammals, a total of 313 animals consisted of three species of rodents and two species of insectivores, collected from an endemic area of this nematode in Aomori Prefecture, were investigated. Two species, Rattus norvegicus (R.n.) and Chimarrogale himalayica (C.h.) were infected with G.n. larvae, and the infection rate was extremely high with 27.2% and 72.7% in the former and latter. The infected animals harbored the larvae of 2-10 (mean: 6.0) in R.N. and 2-40 (10.6) in C.h., and a total of 273 larvae was recovered. The all larvae (18) from R.n. and the vast majority of the larvae (216/255: 82.4%) from C.h. were recovered from the musculature, and many encapsulated larvae were found in these portions of C.h. Taxonomically, all the larvae were identified as the advance third-stage larvae (AdL3) of G.n. The body length was 1,056-2,110 microns, and was larger than those of the naturally-infected AdL3 reported from cold-blooded animals. No morphological alterations or death of the larva was observed. From these results, it would seem that R.n. and C.h. are highly susceptible to G.n. larvae, and has very suitable characteristics as the hosts. Furthermore, a hypothesis is advanced that these mammals serves as the plausible paratenic hosts in the life cycle of G.n. This report is the first record of R.n. (Rodentia) and C.h. (Insectivora) naturally-infected with AdL3 of G.n.

Role of Predation and Parasitism in Growth and Mortality of Yellow Perch in Dauphin Lake, Manitoba

Abstract Total mortality, mortality due to predation, and the contribution of parasite-induced mortality were estimated for yellow perch Perca flavescens infected with the nematode Raphidascaris acus. Total annual natural mortality of yellow perch in Dauphin Lake, Manitoba, was approximately 61%; predation by northern pike Esox lucius accounted for 19% and 45% of natural mortality for female and male yellow perch, respectively. Yellow perch harbored 18 species of parasites, of which R. acus was the most abundant; 95% of all R. acus larvae inhabited the liver. The number of free and encapsulated larvae and nodules in the liver of yellow perch varied seasonally and with fish gender, but it was not correlated with water temperature or fish habitat. Mean intensity but not recruitment increased with age of yellow perch. Density of R. acus (larvae per gram of liver) was highest in young, immature yellow perch and decreased with age in mature yellow perch. Yellow perch with high-density infections had lower cond...

Movse-Cuterebra Animal Systemic Insecticide Test, 1986

Abstract Movse-Cuterebra Animal Systemic Insecticide Test, 1986: White mice are infested ocularly with 5 newly hatched larvae of Cuterebra fontinella Clark. Two days later, female mice are weighed and treated orally with candidate insecticides usually formulated in Tween 20; male mice have i plastic collar placed around their necks to prevent grooming, and their bodies are dipped into 80-200 ml of an emulsion of the candidate insecticide usuallv formulated as an EC (w/v) in xylene (65 parts), Triton X-100 (10 parts), and AI (25 parts). Highest dosages are 100 mg/kg orally and 1% dermally. Four days later, mice are killed and bodies examined carefully for encapsulated larvae usually found in the inguinal region. Effectiveness is determined by comparing numbers of larvae in treated mice with numbers in untreated mice. Probit analysis is conducted with corrected percent-kill data.

Movse-Cuterebra Animal Systemic Insecticide Test, 1985

Abstract White mice are infested ocularly with 5 newly hatched larvae of Cuterebra fontinella Clark. Two days later, female mice are weighed and treated orally with candidate insecticides usually formulated in Tween 20; male mice have a plastic collar placed around their necks to prevent grooming, and their bodies are dipped into 80-200 ml of an emulsion of the candidate insecticide usually formulated as an EC (w/v) in xylene (65 parts), Triton X-100 (10 parts), and AI (25 parts). Highest dosages are 100 mg/kg orally and 1% dermally. Four days later, mice are killed and bodies examined carefully for encapsulated larvae usually found in the inguinal region. Effectiveness is determined by comparing numbers of larvae in treated mice with numbers in untreated mice. Probit analysis conducted with corrected percent-kill data.