Identification Of Larvae Research Articles

Gastropods as intermediate hosts of Angiostrongylus spp. in the Americas: bioecological characteristics and geographical distribution.

BACKGROUND Intermediate hosts are key organisms in maintaining parasite life cycles, because they can act as amplifiers in the transmission from natural reservoirs to humans. One of the most important groups of intermediate hosts for zoonotic nematode infections are gastropods,slugs and snails. These are essential organisms in the larval development of Angiostrongylus species.OBJECTIVES The objective of this paper is to review reports of Angiostrongylus spp. in naturally infected gastropods from the Americas, taking into account the diagnostic methods used in their identification, to be able to provide more accurate list of their intermediate hosts. We also discuss the factors that aid the dispersion of Angiostrongylus spp. in the Americas.METHODS This study reviews scientific publications and book sections on Angiostrongylus spp. in the Americas, including original works assessing larvae of Angiostrongylus in intermediate hosts. The eligible reports were classified accordingly to their geographical location, year of first record, and the larvae identification methodologies used. Digital repositories were used for the search. The bioecological characteristics of the main intermediate hosts are summarised.FINDINGS A total of 29 gastropod species that are naturally infected with Angiostrongylus spp. have been reported as intermediate hosts, 16 of which are land snails, two are freshwater snails, and 11 land slugs.MAIN CONCLUSIONS This study highlights the importance of integrative studies, analysing both the etiological agent and its transmission dynamic in the environment, the biological and ecological characteristics of the hosts, and the impact on host populations. It is necessary to increase interdisciplinary studies to determine the potential epidemiological health risk of angiostrongyliasis in the Americas, and thus be able to establish prevention, monitoring and contingency strategies in the region.

Ontogeny of morphological traits in Oribatella palustris Hammer, 1962, with remarks on juveniles of Oribatellidae (Acari: Oribatida).

In this work, the larva and tritonymph of Oribatella palustris, an Antarctic and Subantarctic species of the Neotropical region are investigated along with supplementary re-description of adults. Comparative characteristics of juveniles of Oribatellidae, especially larvae and tritonymphs, are given based on this study and available literature sources; keys for identification of larvae and tritonymphs of Oribatella are also presented. Previous record of Oribatella palustris from a tropical island of Mexico is questioned.

Molecular identification of larvae for Anisakidae family reduced in benthic and pelagic fish

Molecular identification of larvae for Anisakidae family reduced in benthic and pelagic fish

Impact on beef cattle productivity of infection with anthelmintic-resistant nematodes

ABSTRACTAims: The main goal of the current study was to evaluate, on a commercial beef cattle farm, the impact of infection with gastrointestinal nematodes resistant to both ivermectin (IVM) and moxidectin (MXD) on the productivity of calves.Methods: Male Aberdeen Angus calves, aged 9–11 months, with faecal nematode egg counts (FEC) ≥200 epg and body weight ≥190 kg, were allocated to two herds. Herd A (n = 90) grazed a maize-winter forage crop rotation and Herd B (n = 90) grazed a 2-year-old Agropyrum pasture. On Day 0 in each herd, calves were randomly allocated into five groups (n = 18), which were treated with 0.2 mg/kg IVM; 0.2 mg/kg MXD; 3.75 mg/kg ricobendazole (RBZ), both IVM and RBZ, or remained untreated. Faecal samples collected on Days −1 and 19 were used to determine the percentage reduction in FEC, and genera of the nematodes were determined by the identification of the third-stage larvae recovered from faecal cultures. Total weight gain was determined from body weights recorded on Days −1 and 91.Results: Overall mean reduction in FEC was 42% for IVM, 67% for MXD, 97% for RBZ and 99% for IVM + RBZ. The reduction in FEC for Cooperia spp. was ≤78% for IVM and MXD, and for Haemonchus spp. was 0 and 36% for IVM and MXD, respectively, confirming the presence of parasites resistant to both anthelmintics. Only IVM + RBZ treatment resulted in 100% efficacy against Haemonchus spp. The overall estimated mean total weight gain for calves treated with IVM was 15.7 (95% CI = 11.9–19.7) kg and for calves treated with IVM + RBZ was 28.8 (95% CI = 25–32.5) kg (p < 0.001). Mean total weight gain for calves treated with MXD was 23.5 (95% CI = 19.7–27.2) kg.Conclusions and clinical relevance: In calves naturally infected with resistant nematodes, under the production system assessed here, weight gains were lower in calves treated with anthelmintics that were moderately or highly ineffective compared to those treated with highly effective anthelmintics. These results demonstrate to farmers and veterinarians the importance of a sustainable and effective nematode control under field conditions.

Efecto del consumo de Leucaena leucocephala sobre la carga parasitaria de terneros destetados con pastoreo directo

&lt;p&gt;Con el objeto de evaluar el efecto del consumo de Leucaena sp sobre la carga parasitaria gastrointestinal de terneros destetados, se lle-vó a cabo un ensayo durante 105 días en el departamento Pilagás (Formosa, Argentina). Se seleccionaron 30 terneros y se los dividió en dos lotes: 15 terneros con Leucaena (TRAT c/L) y 15 sin Leucaena (TRAT s/L). El ensayo se desarrolló en un sistema de pastoreo directo donde los animales fueron infestados naturalmente. El lote TRAT c/L pastoreó en una intersiembra de L. leucocephala con Brachiaria brizantha. El grupo TRAT s/L, lo hizo sólo con B. brizantha. Se determinó la cantidad de huevos de parási-tos por gramo (HPG), cultivo e identificación de larvas, valores de hematocrito (Hto) y peso vivo. Los principales géneros recuperados en el coprocultivo fueron: Haemonchus y Trichostrongylus, siguiendo en orden decreciente Bunostomum, Oesophagostomum, Cooperia y Strongyloides. A partir del segundo muestreo, los animales que presentaron valores de Hto ≤ 22% debieron ser tratados con albendazol ya que estaba comprometi-do su estado de salud. Durante el ensayo un solo ternero del TRAT c/L debió ser trata-do, mientras que 9 individuos correspondientes al TRAT s/L requirieron tratamiento. En cuanto a la evolución de HPG, se observaron diferencias significativas en el segundo y cuarto muestreo (p valor de 0,3 y 0,006 respectivamente) a favor del TRAT s/L. Se con-cluye que bajo las condiciones de la presente experiencia, los resultados demostraron un efecto del consumo de L. leucocephala sobre la disminución de HPG, lo que amerita la realización de futuras experiencias para un mejor conocimiento de la alternativa de con-trol integrado de estos parásitos.&lt;/p&gt;&lt;p&gt; &lt;/p&gt;

Drift of Larval Darters (Family Percidae) in the Upper Roanoke River Basin, USA, Characterized Using Phenotypic and DNA Barcoding Markers

Larval fish ecology is poorly characterized because sampling is difficult and tools for phenotypically identifying larvae are poorly developed. While DNA barcoding can help address the latter problem, ‘universal’ primers do not work for all fish species. The Roanoke River in the southeastern United States includes seven darters (Family Percide: Tribe Etheostomatini). We made 393 collections of larval fishes in 2015 and 2018, examined darter larvae for morphometric and pigmentation traits, developed PCR primers amplifying darter DNA, and evaluated three gear types for collecting larval darters. Amplified DNA sequences for 1351 larvae matched archived mitochondrial cytochrome oxidase I sequences for darters occurring in the ecosystem. Larval darters were classified to genus with 100% accuracy using the ratio of pectoral fin length to body length; however, identification to species using morphometrics alone was subject to a misclassification rate of 11.8%, which can be resolved by considering pigmentation patterns. Gear-types varied considerably in their capture efficacy for larval darters; most Percina larvae were collected in drift nets. Larval Percina species appeared in the drift before Etheostoma species in both study years. Application of molecular genetic and phenotypic tools to larval fish identification can advance understanding of larval darter ecology.

Microscophy Identification of Toxocara cati First Stage Larvae and Second Stage Larvae

This study was aimed to identify the ultra structural morphology of Toxocara cati First Stage Larvae and Second Stage Larvae using Light Microscope. Toxocara cati larvae were obtained from adult worm eggs then were treated in phospat buffer saline with comparasion 1 : 1 until it reached the stage of larvae 1 and 2. The shell of egg Toxocara cati were thick and usually consist of three layers. The first layer was inner membrane, the second layer was middle layer and the third was outer layer. The results of larvae morphology that were identified using light microscope showed that the anterior part of Toxocara cati first stage larvae has a dorsal lip and esophagus and intestine on the posterior part but it could not be identified perfectly. The anterior part of Toxocara cati second stage larvae that were identified has three lips that leads directly into the oesophagus. Three lips on the anterior part of Toxocara cati larvae 2 consist of a dorsal lip and two subventral lips. Morphological of Toxocara cati larvae similar with the Toxocara cati adult worms because morphology of larvae and adult stage was difficult to differentiated.

Molecular identification and morphological description of larvae for ten species of the family Pleuronectidae (Pleuronectiformes, PISCES) from Korea

Molecular identification and morphological description of larvae for ten species of the family Pleuronectidae (Pleuronectiformes, PISCES) from Korea

A protocol for fast identification of larval tephritid flies with a community-wide COI reference bank

Identifying dead insect larvae by morphology is mostly challenging but often required in ecological studies, which entails a molecular method. In this study, we developed a protocol of Cytochrome Oxidase c Subunit I (COI) DNA barcoding that could quickly identify larval tephritid flies in a Tibetan alpine meadow. The protocol includes two major operations. The first is to build up a comprehensive reference library after identifying adults of tephritid flies to species by morphology and by COI DNA barcoding sequences. The second is to calculate species-specific delimitation criteria using the sequences in the library, such that COI DNA sequences of insect larvae could be assigned to species using local blast. This protocol was proved successful in the species identification of larval flies among 27 tephritid species belonging to nine genera of subfamily Tephritinae. We suggest that such a protocol can be widely applied to fast identification of insect larvae.

Using DNA Barcodes to Aid the Identification of Larval Fishes in Tropical Estuarine Waters (Malacca Straits, Malaysia).

Larval descriptions of tropical marine and coastal fishes are very few, and this taxonomic problem is further exacerbated by the high diversity of fish species in these waters. Nonetheless, accurate larval identification in ecological and early life history studies of larval fishes is crucial for fishery management and habitat protection. The present study aimed to evaluate the usefulness of DNA barcodes to support larval fish identification since conventional dichotomous keys based on morphological traits are not efficient due to the lack of larval traits and the rapid morphological changes during ontogeny. Our molecular analysis uncovered a total of 48 taxa (21 families) from the larval samples collected from the Klang Strait waters encompassing both spawning and nursery grounds of marine and estuarine fishes. Thirty-two (67%) of the larval taxa were identified at the species level, two taxa (4%) at the genus level, and 14 taxa (29%) at family level. The relatively low rate of species-level identification is not necessarily due to the DNA barcoding method per se, but a general lack of reference sequences for speciose and non- commercial fish families such as Gobiidae, Blenniidae, and Callionymidae. Larval morphology remains important in species diagnoses when molecular matches are ambiguous. A lower ethanol percentage (50%) for larva preservation is also useful to keep the body of larvae intact for morphological identification, and to preserve DNA for subsequent molecular analyses. The 10% Chelex resin used to extract DNA is also cost- effective for long term monitoring of larval fishes. Hence, the DNA barcoding method is an effective and easy way to aid the identification of estuarine larval fishes at the species level.

Fly palaeo-evo-devo: immature stages of bibionomorphan dipterans in Baltic and Bitterfeld amber.

Larvae of flies and gnats (Diptera) form a crucial component of many terrestrial and freshwater ecosystems in the extant biosphere. Larvae of Diptera play a central role in water purification, matter and energy transfer in riparian ecosystems in rivers, carbon cycling in lakes and forests as well as being major decomposers of dead organic matter. Despite all these important roles, dipteran larvae are most often ignored in palaeoecological studies, due to the difficulty of the taxonomic identification of fossil larvae, but also due to the perceived importance of adult dipterans in palaeoentomological and taxonomic studies. Despite that, much information on palaeoecosystems can be gained from studying fossil dipteran larvae, in particular for well preserved specimens from fossil resins (ambers and copals). Since ambers are selectively preserving fauna of trunks and leaf litter, it allows us to learn a lot about xylophages and saprophages of amber forests, such as Eocene Baltic amber forest. Here we present immature stages (larvae and pupae) of the dipteran ingroup Bibionomorpha, from Baltic and Bitterfeld amber forests. We have recorded at least four different larval morphotypes, one with four distinct instars, and at least three pupal morphotypes. One larva is recognised as a new species and can be interpreted either as a representative of a highly derived ingroup of Bibionidae or as a sister species to Bibionidae. Also represented by single larval specimens are the groups Pachyneura (Pachyneuridae) and Sylvicola (Anisopodidae). The majority of the recorded specimens are representatives of the group Mycetobia (Anisopodidae). Due to the abundance of immature stages of Mycetobia, we have been able to reconstruct the number of larval stages (4) and relative growth rate of these fossil dipterans. We discuss implications of these finds.

The using of morphometric indices in the identification of mosquito larvae of the genus Aedes Meigen, 1818 (Diptera, Culicidae) of fauna of Ukraine

As a result of the morphometric analysis on the mosquito larval structures of the genus Aedes Meigen, 1818 from our own collections and literature analyses, a wide variation in quantitative and qualitative indices was revealed. The morphological and metric indices of mosquito larvae are quite similar and vary under the influence of environmental factors, which must be taken into account when determining species. The tables for rapid determination of common mosquito species of Ukraine, with the use of external features that do not require the manufacture of permanent slide mounts, are given in the article. All modern keys for identification are based on dichotomous tables. This process is quite long, does not take into account the individual variability and does not allow the quick identification of species. After analyzing the literature and summing up the result, it can be confirmed that 35 species of bloodsucking mosquitoes of the genus Aedes occur within Ukraine, so there is a need to create a new regional key. The purpose of the study is to propose tables for determining the common mosquitoes of the genus Aedes in Ukraine using external morphometric characteristics. The material used for this study was collected by the author in March–October of 2017–2018 at the territory of Volyn Region. Over the entire study period, a total of 185 samples were collected, 1580 species of mosquito larvae of the genus Aedes were analyzed. During the work, 12 morphometric characters of bloodsucking mosquitoes were used and the results were tabulated to determine species of the genus Aedes. The proposed keys for definition are presented in the form of a tables and have certain advantages, such as, the ability not to take into account the characters lost in the process of collecting or storing and to complete the diagnostics on other features, that is quite problematic with the dichotomous keys, since they have a certain algorithms. The proposed tables are based on the using of quantitative and qualitative external characters and do not require the preparation of slide mounts in further work. There is also the possibility of creating an electronic key, which will greatly facilitate the work on the determination of the larvae in the genus Aedes.

Spawning time of Acanthaster cf. solaris on the Great Barrier Reef inferred using qPCR quantification of embryos and larvae: do they know it\u2019s Christmas?

Outbreaks of crown-of-thorns seastars (CoTS; Acanthaster spp.) are a major contributor to degradation of Indo-Pacific coral reefs. Understanding the dispersal and fate of planktonic life stages is crucial to understand and manage outbreaks, but visual detection of CoTS larvae is challenging. We apply a quantitative PCR (qPCR) assay to enumerate CoTS larvae in a 3-year time series of plankton samples from two reefs (Agincourt and Moore Reefs) on the Great Barrier Reef. Plankton surveys were complemented with settlement assays, and benthic surveys of juvenile and adult densities over time. Only one out of 109 plankton samples from Agincourt Reef had detectable CoTS mtDNA compared to 41 out of 575 samples from Moore Reef. This may be explained by differences in adult densities, or differences in connectivity and larval retention. Detections of larval CoTS were restricted to summer (November–February), with first detections each year coinciding with water temperatures reaching 28 °C and peak detections late December. A disproportionate number of larval detections occurred in 7 days around full moon. Complementary sampling of settlement and post-settlement life stages confirmed that elevated densities of CoTS larvae at Moore Reef translated to high rates of settlement adding to infestations at this reef. Moreover, there were declines in the detection of larvae, as well densities of juvenile and adult CoTS at Moore Reef, in 2017 and 2018. This study demonstrates that qPCR for genetic identification and quantification of larvae can assist to elucidate life history parameters of nuisance species difficult to obtain with other tools.

Identifying nauplial stages of the Black Sea copepods of Calanidae family in fish larvae guts

Nauplial stages of copepods are known to be the main food items for fish larvae. Their identification in fish larvae guts is usually a difficult task and a time-consuming procedure. Original approach to identification of larvae and juvenile fish common food items – nauplial stages of the Black Sea copepods of family Calanidae – is proposed. This work is a continuation of the initiated studies on the developing a method for determining the juvenile copepod stages from fish larvae guts. On the example of nauplial stage III of Calanus euxinus Hulsemann, 1991, specific features that can be used in identifying nauplial stages of three species of the Black Sea copepods from fish larvae guts are shown.

Non‐destructive DNA extractions from fly larvae (Diptera: Muscidae) enable molecular identification of species and enhance morphological features

AbstractInsects preserved as reference specimens are important in a wide range of fields, including health, pest management and forensics. The aim of the present study was to test a non‐destructive DNA extraction method on samples of soft‐bodied insects, fly larvae, which are otherwise hard to identify morphologically. This not only provides DNA enabling molecular identification but also retains morphological reference specimens for samples belonging to collections and museums that cannot be destroyed. In this work, fly larvae identified as belonging to the family Muscidae were non‐destructively processed. DNA barcoding molecular identification allowed most of these specimens to be assigned to species. Furthermore, the visibility of seven important larval morphological characters – anterior and posterior spiracles, mouth hooks, cephalopharyngeal skeleton, locomotory welts, segmentation and colour – was assessed pre‐ and post‐DNA extraction. It was found that the morphology generally did not deteriorate post‐DNA extraction but actually improved through increased visibility of internal features. Therefore, this non‐destructive DNA extraction method not only allowed COI barcode sequences to be obtained, but also enabled a better morphological identification of the fly larvae retaining physical reference voucher specimens and avoiding the need for dissections.

Survey of lungworm infection of domestic cats in Hungary.

From 61 settlements of 12 Hungarian counties, 303 domestic cats were included in this survey. Between autumn 2016 and spring 2018, fresh faecal samples were randomly collected and examined by flotation and by the Baermann-Wetzel method for the presence of lungworm infection. No eggs of Eucoleus aerophilus were detected. Morphological identification of first instar larvae (L1) was also carried out. In the faeces of 60 cats (19.8%) from 17 settlements and Budapest, L1 of Aelurostrongylus abstrusus were found. More than half of the cats were from the western part of the country. The average number of larvae per gram of faeces was 190.2 ± 304.88. These results are in line with the former findings on the prevalence of aelurostrongylosis of domestic cats in Hungary. In addition, Oslerus rostratus was also found for the first time in the faecal samples of three cats from the eastern part of the country, infected also with Ae. abstrusus. The average age (2.51 ± 1.26 years) of infected cats indicates that lungworm infection is more common among younger cats. No relationship was found between the lung-worm infection and the sex of cats. Non-neutered cats had a significantly higher proportion of lungworm infections. Two-thirds of the infected cats were apparently healthy, and only 19 individuals showed clinical signs of respiratory disorders.

A Direct and Simple Method to Assess Drosophila melanogaster's Viability from Embryo to Adult.

In Drosophila melanogaster, viability assays are used to determine the fitness of certain genetic backgrounds. Allelic variations can result in partial or complete loss of viability at different stages of development. Our lab has developed a method to assess viability in Drosophila from embryo to fully mature adult. The method relies on quantifying the number of progeny present at different stages during development, starting with hatched embryos. After embryos have been quantified, additional stages are counted, including L1/L2, pupae, and mature adults. After all stages have been examined, a statistical analysis such as the chi-square test is used to determine if there is a significant difference between the starting number of progeny (hatched embryos) and later stages culminating in the observed number of adults, thus rejecting or accepting the null hypothesis (that the number of hatched embryos will be equal to the number of larvae, pupae, and adults recorded throughout the stages of development). The primary advantage of this assay is its simplicity and accuracy, as it does not require an embryo rinse to transfer them to the food vial, avoiding losses from technical errors. Although the protocol described here does not directly examine L2/L3 larvae, additional steps can be added to account for these. Comparing the number of hatched embryos, L1, pupae, and adults can help determine if viability was compromised during the L2/L3 stages for further studies (the use of colored food helps with visual identification of larvae). Overall, this method can help Drosophila researchers and educators determine when viability is compromised during the fly life cycle. Routine assessment of stocks using this assay can prevent accumulation of secondary mutations that may affect the phenotype of the originally isolated mutant, especially if the original mutations affect fitness. For this reason, our lab maintains multiple copies of each of our Dm ime4 alleles and routinely checks the purity of each stock with this method in addition to other molecular analyses.

Human intestinal myiasis caused by Clogmia albipunctata larvae (Diptera: Psychodidae): First report in Egypt

This is the first case report in Egypt and Middle East region of human intestinal myiasis caused by Clogmia albipunctata larvae. A 36-year-old male patient presented to the Outpatient Clinic of Internal Medicine in Beni-Suef University Hospital complaining of abdominal pain, bloating, and diarrhea intermittent with constipation. Patient's stool sample was referred to the Department of Medical Parasitology for examination of passed larvae and treatment prescription. Examination of larvae by light and scanning electron microscopy confirmed the morphological identification of fourth instar larvae of C. albipunctata. Human intestinal myiasis is an unusual cause of gastrointestinal manifestations.

EFFECT OF KILLING METHODS AND PRESERVATIVE SOLUTIONS ON THE LARVAL BODY LENGTH OF CHRYSOMYA MARGINALIS (DIPTERA: CALLIPHORIDAE)

Estimation of the minimum post mortem interval (PMI) is the essential role of forensic entomology. The accurate determination of this interval depends on the correct larval identification and accurate estimation of larval age. One method of larval age estimation is the larval length measurement. Killing methods and the type of preservative solutions can greatly affect the larval length and therefore reduce the accuracy of PMI estimation. This study was conducted to determine which killing method and preservative can preserve the best larval length of Chrysomya marginalis. Third instar C. marginalis larvae were either placed live in the preservatives, 10% formalin, 70% ethanol, XAA, Kahleˊs solution and Pampleˊs fluid, or killed by boiling water (BWK) before being placed in the same preservatives. The larval length was recorded after day 1, 3, 5, 7 and 15 and for BWK larvae only; the length was recorded immediately after killing the larvae and before being placed in the preservatives. The larval length of C. marginalis was significantly affected by killing method (live or BWK) and the type of the preservative used. The mean length of the larvae placed live in the preservativesdecreases significantly than those killed by boiling water before being placed in the preservatives.It was observed that killing larvae by boiling water then preserved in 10% formalin and Kahleˊs solution is the best method for preserving the larval length, but 10% formalin is not recommended if DNA recovery is desired.

How Does eDNA Compare to Traditional Trapping? Detecting Mosquito Communities in South-African Freshwater Ponds

Improved biomonitoring of mosquitoes requires an in-depth understanding on occurrences of both vector and non-vector species, in larval, and adult stages. Accurate descriptions of the ecological context in which mosquitoes thrive remain limited, particularly for larval stages. The aim of this study was to develop a mixed-amplicon eDNA approach to assess (i) whether mosquito larval communities of stagnant fresh-water bodies can be detected using a Culicidae-specific primer and (ii) how these results compare to traditional trapping of adult mosquitoes. Results from 32 ponds inside and outside Kruger National Park, South Africa show that our primer detected mosquito eDNA. However, it yielded only a subset of the species found using adult trapping methods. Particularly the less frequent and container-breeding species were not found. Our approach provides the first steps toward an eDNA-based method to assess the entire community of larval-stage mosquitoes. It may thereby overcome current taxonomic hurdles presented by morphological identification of larvae. As such, it holds great promise for biomonitoring and ecological studies of mosquitoes.