Levels Of Parasitism Research Articles

DESCRIPTIVE EPIDEMIOLOGY OF THE MAIN INTERNAL PARASITES ON ALTERNATIVE PIG FARMS IN FRANCE.

Alternative pig farms, which do not raise animals in closed buildings with slatted and/or concrete floors, have critical points that need particular attention. Internal parasitism is one, as the farming conditions in such structures are more favorable to the development and survival of parasites. The objectives of this study, carried out on 70 alternative farms in continental France, were to (i) estimate the frequency and level of infestation by the main internal parasites on these farms, and (ii) define their typology according to the level of parasitism. For this purpose, fecal samples were taken for coprological analysis from 10 sows, 10 pigs aged 10-12 wk, and 10 pigs at the end of the fattening period. Blood samples were also taken for serological analysis (targeting Ascaris suum and Toxoplasma gondii) from 10 sows and 10 pigs at the end of the fattening period. Of the 70 farms, only 5 had no helminth egg or coccidian oocyst. Coccidia oocysts were observed in 79% of the farms, while eggs of Oesophagostomum spp./Hyostrongylus rubidus, Ascaris suum, and Trichuris suis were found in 47%, 16%, and 36% of the farms, respectively. On each infested farm, an average of 56.8% of sows, 23.8% of grower pigs, and 38.9% of finisher pigs were parasitized. At least 1 Ascaris suum-seropositive finisher pig was found on 91% of the farms, and at least 1 Toxoplasma gondii-seropositive finisher pig or sow on 60% of the farms. Data on housing, animal management, and health management (particularly parasite control) were collected to characterize the typology of farms according to their level of parasitism. The variables defining these farm typologies differed according to the parasites. Access to the outdoors for breeding stock was a characteristic of the farms most heavily infested with helminths or T. gondii. Conversely, the farms with the lowest frequency of coccidia oocyst infestation were characterized by free-range farrowing facilities and also by the presence of slatted floors, mostly plastic in our study, rather than straw bedding in the farrowing rooms. The level of biosecurity concerning the storage of straw for pig bedding was another discriminating factor for parasitism level of helminths and T. gondii. Farms with the highest levels of helminth parasitism were more likely not to practice an all-in-all-out postweaning system and to deworm their grower/finisher pigs less frequently than farms with the lowest levels of helminth parasitism.

Preliminary Evaluation of Anti-trypanosome Impact of Methanol, Alkaloid and Flavonoid Extracts of Sarcocephalus latifolius in T. Brucei Infected Mice

The menace of ravaging infection of trypanosomiases in Africa is of concern in view of the parasites resistance to drug coupled with the cost and extended treatment practice with adverse effect. The prospect of exploiting medicinal plants as alternative in treating illnesses is heightened. This study evaluated the anti-trypanosome activities of the methanol, alkaloid and flavonoid extracts of sarocephalus latifolius leaves. Acute toxicity of the extracts was obtained using the Lorke’s method. In vitro and in vivo analysis of the test plant leaves was determined using different concentrations. The in vitro anti-trypanosome effect of the crude methanol, alkaloid and flavonoid extracts of Sarocephalus latifolius leaf showed that the activity was determined based on dosage with more influence at 4 mg/mL in relation to 0.4 and 0.04 mg/ml. There is significant different (p<0.05) between mice treated with extract and the reference drug. The acute toxicity test was safe as no mortality was recorded at 5000mg/kg of bodyweight of mice. However, in vivo Anti-trypanosome activity of the crude extract at 250 and 500mg/kg bodyweight exposed a trend of increase in the parasite level which was observed when compared with standard control. But, elongation of life in mice was observed. Methanol treatment of mice lasted for about nine (9) days before mortality occurred while, that of alkaloid and flavonoid lasted for about five (5) days respectively subsequent to mortality. Consequently, the in vivo anti-trypanosome activity of methanol, alkaloid and flavonoid extracts did not eradicate the parasite in the blood of the poisoned mice but, appear to have prolonged the life of the treated animal when compared with the infected untreated group. Therefore, methanol extract of Sarocephalus latifolius leaf having the most influence on mice has illustrated more potential in anti-trypanosome activity which can be utilize in controlling African trypanosomiasis.

Developing an adaptive management approach to cowbird control on the Santa Clara River, California

AbstractBrood parasitism by the brown‐headed cowbird (Molothrus ater) has caused population declines for conservation‐reliant songbird species such as the federally and state endangered subspecies least Bell's vireo (Vireo bellii pusillus). Although cowbird trapping has increased vireo populations, it is costly, and may prevent the development of parasitism‐avoidance behaviors and result in high rates of non‐target species captures. Therefore, wildlife managers have a compelling interest in evaluating multiple means of cowbird control. We conducted a study between 2016 and 2018 on the Santa Clara River (SCR) in Ventura County, California, USA, to test how the removal of cowbird traps would affect cowbird parasitism of the vireo. At our control site, cowbird trapping occurred in spring using modified Australian crow (Corvus spp.) traps. At our treatment site, we stopped this method of trapping and instead used target‐netting of individual cowbirds and a very short duration trap to capture specific individual cowbirds (i.e., contingency trapping). We also tested the impact of shortening the cowbird trapping period on nest parasitism rates, and used point counts to compare cowbird densities between sites. Additionally, we compared the costs of these techniques. A shorter trapping period still resulted in a large number of cowbird captures on the control site (n = 452 captures) with no observed brood parasitism (n = 67 nests). On the treatment site, cowbird parasitism rates varied from 0% to 14% (n = 75 broods). The target‐netting method was not effective for capturing female cowbirds, probably because of their low densities. The short‐term contingency trapping method effectively removed female cowbirds in the vicinity of vulnerable vireo nests. Cowbird traps captured >300 individuals of 9 different non‐target species each year on the control site, whereas target‐netting and contingency trapping resulted in only 8 captures of 4 different non‐target species. Costs of continuous trapping for 2 months versus point counts, nest monitoring, and contingency trapping were $21,100.00 versus $16,996.00, respectively. Based on these findings, we recommend that an adaptive cowbird management program to benefit songbird populations should consider using regular point counts and nest monitoring to provide data on cowbird impacts, in lieu of continued intensive trapping without monitoring. Thresholds for the density of cowbird females and the allowable level of parasitism for host species should also be established to guide an adaptive cowbird management program. Short‐term contingency trapping based on the thresholds should be considered, but restoration of native vegetation, especially in southwestern riparian areas, is also crucial and effective at limiting parasitism, and so should strongly be considered. Lastly, large numbers of non‐target species captures in cowbird traps are probably having consequential impacts to these species, and need to be monitored and minimized.

PARASITISM IN HYBRID SUNFISH (LEPOMIS SPP.): PATTERNS OF INFECTION AT THE INDIVIDUAL AND COMMUNITY LEVEL.

Sunfish (Lepomis spp.) are among the most common piscine inhabitants of freshwater lakes and ponds in North America. Lepomis spp. breed at the same time creating hybrid zones, where genetically distinct populations mate and produce mixed offspring that are sexually viable hybrids. One aspect of hybridization that may have important consequences is parasitism and its patterns of recruitment in the hybrid sunfish. This study investigated these patterns both at the level of the individual parasite species as well as in the parasite communities infecting the fish. Two sample sites possessing hybrid sunfish populations were investigated: 1 system had bluegill sunfish (Lepomis macrochirus), redear sunfish (Lepomis microlophus), and their hybrids, while the other system had bluegill sunfish (L. macrochirus), green sunfish (Lepomis cyanellus), and their hybrids. The hybrids were infected by mostly generalist parasites that commonly infect all Lepomis spp. Most of the individual parasite species followed a dominance pattern (59.1%) of infection, where parasite abundance in hybrids resembled at least one of the parental species, with the remainder exhibiting intermediate levels of parasitism, supporting an additive pattern of parasite recruitment (40.1%). At the community level, the patterns of parasite recruitment differed in L. macrochirus × L. microlophus hybrids, which showed a dominance pattern, and L. macrochirus × L. cyanellus hybrids, which showed an additive pattern of parasite recruitment. These differences in parasite recruitment between hybrid groups may be attributed to varying degrees of dietary and niche overlap between the parental species in the 2 study systems.

Implications of sampling bias and population behaviour in the study of parasitoid-based biocontrol of Listronotus bonariensis in New Zealand’s exotic pasture ecosystems

ABSTRACT New Zealand’s economically vital exotic pastures are unique in their low complexity making them highly susceptible to invasive pest species such as the Argentine stem weevil Listronotus bonariensis. This field-based contribution further examined the ecology of the adult weevil and its parasitoid control agent Microctonus hyperodae. This included factors that affect field sampling accuracy, interpretation of population density and parasitism estimates. Compared to adult population estimates measured via turf flotation, suction sampling (G-vac) showed c.30% under-estimation of population densities while parasitism rates were over-estimated by c.26%. The bionomic implications of the sampling biases are discussed as they relate to the recently observed sharp declines in L. bonariensis parasitism. The weevil’s field parasitism rates showed no relationship to population density again confirming the parasitoid’s very high host searching efficiency. This study also coincided with meteorological conditions (>30°C) that resulted in a very large L. bonariensis ‘swarming’ event. The mass emigration from the experimental plots left only a low residual population of parasitised weevils that typically do not fly. Therefore, measured L. bonariensis populations and their M. hyperodae parasitism levels cannot always be presumed to be solely the result of population dynamics in situ.

Host-parasite relationships in invasive species: macroecological framework

Despite considerable research effort, many aspects of the host-parasite relationships and parasite spatial distribution in invasive hosts remain poorly understood due to complex and context-dependent phenomena related to both the bioinvasions and the parasitism. Using macroecological patterns and theory is a useful approach to analyzing parasitological observations, but in practice parasite ecology and classical macroecology are disconnected. We propose a new framework that can use the conventional parasitology sampling data much more effectively. The innovative concept combines the data inferred from populations, infra- and component communities of parasites and the application of a macroecological approach in the analysis of complex and frequently hidden relationships in host-parasite systems. This comparative analysis draws on parasite data across regions and host species at different organizational (population vs. community) and hierarchical (infra vs. component community) levels of parasites. Our framework based on assessing and analysis of parasitological and ecological indexes, including descriptors of parasite species richness (individual and total), infection parameters, parasite aggregation (Taylor´s power law) and macroecological models (abundance-variance and abundance-occupancy relationships), can produce mechanistic explanations of the Enemy Release Hypothesis and unravel host-parasite relationships of an invasive host and its parasites. Moreover, abundance-variance and abundance-occupancy relationships, core-satellite species hypothesis, patterns on the aggregation and the frequency distribution of prevalence, infrapopulation size and individual parasite species richness provide useful tools to distinguish co-introduced and acquired parasites in communities of the invasive host based on quantitative descriptors. We hope that our framework becomes widely applied as it can potentially contribute to enhance future practice and research in biodiversity conservation and control of invasive species.

Tanggap Parasitoid Braconidae (Hymenoptera) Terhadap Hama Invasif Liriomyza trifolii (Burgess) (Diptera: Agromyzidae) pada Tanaman Sayuran dan Hias di Bali

Response of Braconid Parasitoid Against Invasive Pest, Liriomyza trifolii (Burgess) (Diptera: Agromyzidae) on Vegetable and Ornamental Crops in Bali. Research on the respopnse of Braconid parasitoids to the invasive pest, Liriomyza trifolii that attacks ornamental plants and vegetables in Bali, was carried out from September 2020 to March 2021. This study aimed to determine the type and abundance of parasitoid populations that responded to Liriomyza trifolii on host plants in the field. In addition, this study also aims to evaluate the level of parasitization of each parasitoid against L. trifolii. This study used a purposive sampling method by taking leaf samples that showed active symptoms of Liriomyza larvae in the leaves of plants. The research focused on vegetables and ornamental plants cultivated in lowlands <500 meters above sea level (masl), mediumlands 500-1000 meters above sea level and highlands> 1000 meters above sea level. The results showed that there were two species of Braconid parasitoids that responded to Liriomyza trifolii in the field, namely Opius dissitus and Opius cromatomiyae. The relative abundance and degree of parasitization of the two parasitoids showed variation between host plant species and altitude. The relative abundance of O. dissituse was high in chrysanthemum (10.81%) at an altitude of >1000 masl and low in long beans (0.53%) at an altitude of <500 masl. The highest relative abundance of O. cromatomiyae was in marigold flowers (51.18%) at an altitude of <500 masl and the lowest was in chrysanthemum (44.83%) at an altitude of > 1000 masl. The highest level of parasitization of O. dissitus was found in pakcoy plants (50.00%) at an altitude of >1000 masl and the lowest was in mustard plants (6.06%) at an altitude of <500 masl. The highest level of parasitization of O. cromatomiyae was in celery (33.33%) at an altitude <500 masl and the lowest was in tomato plants (25.00%) at an altitude> 1000 masl. Both species of Braconid parasitoids have high potential as biological control agents for L. trifolii as indicated by their relative abundance and high levels of parasitization against these invasive pests.

Biological Control Options for the Golden Twin-Spot Moth, Chrysodeixis chalcites (Esper) (Lepidoptera: Noctuidae) in Banana Crops of the Canary Islands.

Simple SummaryThe golden twin-spot moth, Chrysodeixis chalcites, is a pest whose larvae cause serious skin injuries to banana fruits in the Canary Islands, reducing their commercial value. The use of Integrated Pest Management (IPM) strategies (cultural, biological, and chemical control) is recommended for the effective and sustainable management of this pest. The identification of its parasitoids and the quantification of their effects on pest populations are essential for the development of biological controls. In this study, we conducted an extensive survey to identify the most important parasitoid species of Ch. chalcites and evaluated the efficacy of the egg parasitoid Trichogramma achaeae as a biological control agent in banana plantations in the Canary Islands. Our findings indicate that populations of native parasitoids can exert a certain degree of natural control over Ch. chalcites. However, their naturally occurring populations are insufficient to minimize the damage caused by this pest. Thus, the development of IPM programs based on the use of selective insecticides, the conservation of natural enemies and inundative releases of mass-reared wasps is also necessary. The parasitoid T. achaeae has been identified as a promising biological control agent of Ch. chalcites in greenhouse banana crops, but it is necessary to carry out further studies to establish the most appropriate release strategies.Chrysodeixis chalcites (Esper) (Lepidoptera: Noctuidae) is a significant pest in banana plantations in the Canary Islands. Field surveys were carried out to identify its naturally occurring parasitoids and estimate their parasitism rates between September 2007 and October 2010. Ch. chalcites was parasitized by six different larval/pupal parasitoid species: Cotesia sp., C. glomerata L. (Hym.: Braconidae), Aplomyia confinis Fallén (Dip.: Tachinidae), Hyposoter rufiventris Perez, Ctenochares bicolorus L. (Hym.: Ichneumonidae) and Aleiodes sp. (Hym.: Braconidae). Among them, Cotesia sp. was the most frequent species, accounting for 8.18% of parasitized larvae. High levels of egg parasitism were detected, with Trichogramma achaeae Nagaraja and Nagarkatti (Hym.: Trichogrammatidae) being the most widely distributed egg parasitoid. A greenhouse assay was also carried out on a commercial banana crop with the aim of evaluating the potential of T. achaeae as a biological control agent and compared with a chemical control. Five periodic inundative releases of 35 adults/m2 every 21 days were necessary to achieve an adequate parasitism level (56.25 ± 1.61%). Moreover, there was 15.75% less foliar damage in the biological control plot compared to the chemical control plot. These results indicate that T. achaeae could be a promising biocontrol agent of Ch. chalcites in greenhouse banana crops.

Aphid‐parasitoids trophic relationship in a cereal crop succession system: Population oscillation and food webs

Abstract In the 1970s, cereal aphids populations (specially Metopolophium dirhodum) were out of balance in the subtropical region of South America and a successful biological control program with the introduction of parasitoids restored equilibrium. After that, changes in crop systems may have affected aphid‐parasitoid communities. The objective of this work was to evaluate the current assemblage of cereal aphid parasitoids, describing their oscillations, parasitism level, and trophic relationships in food webs in a cereal succession system (wheat‐corn‐oat) currently adopted in this region. Over a year, the associated parasitoid/hyperparasitoid species were inventoried by field‐exposed Rhopalosiphum padi, Schizaphis graminum, M. dirhodum, and Sitobion avenae (recruitment method) and by Moericke traps. Six species of primary parasitoids were sampled in both aphids and traps with the same abundance sequence: A. platensis, A. rhopalosiphi, L. testaceipes, D. rapae, A. uzbekistanicus, and A. ervi. Parasitism and complexity of food webs were higher during the wheat season (winter–spring), decreasing in corn (summer) and increasing again in oat (autumn). In the current assemblage of cereal aphid parasitoids in the subtropical region of South America, three species of parasitoids that were already present before the biological control program and three that were introduced oscillate in abundance throughout the year, resulting in an alternation of the complexity of the food webs and in the levels of parasitism in the crop seasons. A. platensis and A. rhopalosiphi are the most abundant species and A. rhopalosiphi remains fundamental in the control of M. dirhodum and S. avenae.

Paromomycin Reduces Vairimorpha (Nosema)ceranae Infection in Honey Bees but Perturbs Microbiome Levels and Midgut Cell Function.

Paromomycin is a naturally occurring aminoglycoside antibiotic that has effects on both prokaryotic and eukaryotic microbes. However, previous reports have indicated that it has little effect on microsporidia, including Vairimorpha (Nosema) ceranae, in cell culture models. V. ceranae is one of a number of microsporidia species that cause disease in honey bees and substantial efforts to find new treatment strategies for bees that are infected with these pathogens are ongoing. When testing compounds for potential activity against V. ceranae in whole organisms, we found that paromomycin reduces the infection intensity of this parasite. Critically, the necessary doses of paromomycin have high activity against the bacteria of the honey bee microbiome and cause evident stress in bees. Microsporidia have been shown to lack an essential binding site on the ribosome that is known to allow for maximal inhibition by paromomycin. Thus, it is possible that paromomycin impacts parasite levels through non-cell autonomous effects on microsporidia infection levels via effects on the microbiome or midgut cellular function. As paromomycin treatment could cause widespread honey bee health issues in agricultural settings, it does not represent an appropriate anti-microsporidia agent for use in the field.

Adventive Larval Parasitoids Reconstruct Their Close Association with Spotted-Wing Drosophila in the Invaded North American Range.

Two species of larval parasitoids of the globally invasive fruit pest, Drosophila suzukii (Diptera: Drosophilidae), Leptopilina japonica, and Ganaspis brasiliensis (both Hymenoptera: Figitidae), were detected in British Columbia, Canada in 2016 and 2019, respectively. Both are presumed to have been unintentionally introduced from Asia; however, the extent of their establishment across different habitats with diverse host plants used by D. suzukii was unclear. In addition, there was no knowledge of the temporal dynamics of parasitism of D. suzukii by these two parasitoids. To address these gaps, we repeatedly sampled the fruits of known host plants of D. suzukii over the entire 2020 growing season in British Columbia. We documented the presence of L. japonica and G. brasiliensis and estimated the apparent percentage of D. suzukii parasitized among host plant species. Across a large region of southwestern British Columbia, both L. japonica and G. brasiliensis were found to be very common across a variety of mostly unmanaged habitats over the entire course of the season (May-October) in the fruits of most host plants known to host D. suzukii larvae. Parasitism of D. suzukii was variable (0-66% percent parasitism) and appeared to be time-structured. Our study demonstrates that the close association between the two larval parasitoids and D. suzukii that exists in Asia has evidently been reconstructed in North America, resulting in the highest parasitism levels of D. suzukii yet recorded outside of its area of origin.

Colony-Level Viral Load Influences Collective Foraging in Honey Bees.

Nutrition is an important component of social insect colony health especially in the face of stressors such as parasitism and viral infections. Honey bees are known to preferentially select nectar and pollen based on macronutrient and phytochemical contents and in response to pathogen loads. However, given that honey bees live in colonies, collective foraging decisions may be impacted directly by forager infection status but also by colony health. This field experiment was conducted to determine if honey bee viral infections are correlated with pollen and nectar foraging and if these associations are impacted more by colony or forager infection. By comparing regressions with and without forager and colony variables and through structural equation models, we were able to determine the relative contributions of colony and forager virus loads on forager decisions. We found that foragers had higher numbers and levels of BQCV and CBPV but lower levels of DWV viruses than their respective colonies. Overall, individuals appeared to forage based a combination of their own and colony health but with greater weight given to colony metrics. Colony parasitism by Varroa mites, positively correlated with both forager and colony DWV-B levels, was negatively associated with nectar weight. Further, colony DWV-B levels were negatively associated with individually foraged pollen protein: lipid ratios but positively correlated with nectar weight and sugar content. This study shows that both colony and forager health can simultaneously mediate individual foraging decisions and that the importance of viral infections and parasite levels varies with foraging metrics. Overall, this work highlights the continued need to explore the interactions of disease, nutrition, and genetics in social interactions and structures.

Investigation of The Effect of Curcumin on Oxidative Stress, Local Inflammatory Response, COX-2 Expression, and Microvessel Density in Trichinella Spiralis Induced Enteritis, Myositis and Myocarditis in Mice.

SummaryBackgroundCurcumin exerts anti-oxidant and anti-inflammatory properties that have proven to be of value in the management of several parasitic infections.ObjectiveInvestigation of the value of curcumin in the management of trichinosis either alone or as an adjuvant to albendazole.MethodsAnimals received either curcumin 150 mg/kg, curcumin 300 mg/kg, albendazole 50 mg/ kg or combined curcumin 150mg/kg and albendazole 50 mg/kg and were compared with control infected and non-infected mice. Estimation of intestinal and muscular parasitic load and blood malondialdehyde level, in addition to the histopathological examination of small intestine, skeletal muscle tissue and heart was performed. Also, assessment of the local expression of cyclooxygenase-2 enzyme (COX-2) and CD34 in these samples was done by immunohistochemistry.ResultsCurcumin was found efficient in reducing parasitic load. It also lowered serum MDA level, local COX-2 and CD34 expression. An evident anti-inflammatory effect of curcumin was observed in intestinal, skeletal muscle and cardiac muscle histopathological sections.ConclusionThe anti-inflammatory, anti-oxidant and anti-angiogenic effects of curcumin can help to improve trichinellosis-induced pathology. Curcumin can therefore be of value as an adjuvant therapy to conventional antiparasitic agents and can also produce promising results when used alone at higher doses.

Parasite Community Analysis of The Gray Snapper Lutjanus Griseus (Perciformes,Lutjanidae) in a Tropical Region of The Southern Gulf of Mexico.

SummaryThe gray snapper Lutjanus griseus is a commercially important fish species along its distribution range in the western Atlantic Ocean. However, despite its importance, there is still little knowledge about its parasitic fauna for the Mexican coasts of the Gulf of Mexico. The aims of this research were to generate a list of the parasitic fauna present in juvenile gray snapper L. griseus from a coastal lagoon located in southeastern Mexico, to evaluate the infection levels of parasites and to determine the relationship between the abundance of parasites and the fish size and condition factor. Samples of L. griseus (12 – 29.2 mm) were obtained in two periods of the year (dry and rainy seasons) to examine the intra-annual variability of its parasitic fauna. A total of 17 parasite species were recorded belonging to six taxonomic groups (Myxozoa, Monogenea, Digenea, Cestoda, Nematoda and Acanthocephala). The highest levels of infection (abundance, prevalence and intensity of infection) were found for the monogeneans Euryhaliotrema griseus and Euryhaliotrema fastigatum. There were no significant correlations between the total abundance of parasites and the fish condition and size (total length) in not any of the two seasons studied, suggesting that the body size and the biological condition index of the host did not directly influence the abundance of parasites in early life stages of L. griseus. Moreover, the species of parasites found that could be zoonotic for humans through the consumption of raw or inadequately cooked fish were the nematodes Contracaecum sp. type 1, Contracaecum sp. type 2, Cucullanus pargi and Pseudoterranova sp. The presence of the monogeneans E. griseus and E. fastigatum was also highlighted because these ectoparasite species are known to cause harm to fish under culture systems. All the parasite species found in this study, except nematodes, were new records of geographic distribution.

A real-time quantitative PCR assay using hydrolysis probes for monitoring scuticociliate parasites in seawater

Scuticociliatosis is a serious disease that affects flatfish during culture and against which no effective control measures have yet been developed. Monitoring parasite levels in the water may be a valuable way of establishing the risk of infection and enabling appropriate control measures to be taken, thus representing an advance in controlling the disease. To achieve this objective, we have designed a quantitative real-time PCR (qPCR) assay using primers (f / r ITS2) and a hydrolysis probe that specifically amplify a region of the internal transcribed spacer 2 (ITS2) of the main aetiological agents of scuticociliatosis: Philasterides dicentrarchi and Miamiensis avidus. The slope (m), efficiency (E) and linearity (R2) determined from the standard curves generated are within the optimal values for qPCR. The high analytical sensitivity of the qPCR assay enables quantification of less than 120 pg of DNA per μL of reaction and detection of 1 ciliate per assay. The qPCR assay also exhibits high precision, with intra- and inter-assay coefficients of variation (CV) of respectively 0.27 and 7.57%. The protocol developed for isolating and quantifying ciliates seawater samples it has a recovery efficiency greater than 75% when the ciliate levels are between 103 and 2 × 103 ciliates/L and the turbidity of the water does not exceed one nephelometric turbidity unit (NTU). The real-time qPCR assay developed is a useful and appropriate tool for the specific and sensitive monitoring of scuticociliates in the water used in flatfish farms, enabling the establishment of effective prevention and control programmes.

Ascaridoid nematodes infecting commercially important marine fish and squid species from Bangladesh waters in the Bay of Bengal

Parasitic ascaridoid nematodes occur in a wide range of marine organisms across the globe. Some species of the anisakid family (Ascaridoidea: Anisakidae) can cause gastrointestinal disease in humans (i. e. anisakidosis). Despite their importance as potentially hazardous parasites, the occurrence and infection characteristics of ascaridoids are still poorly known from many host species and geographical areas. This study investigated the diversity and infection levels of ascaridoid parasites in various commercial fish and squid host species off Bangladesh. Fish and squid specimens were visually inspected for nematodes using the UV-press method. Nematodes were assigned to genus level based on morphology and identified by sequence analyses of the entire ITS region and partial 28S rDNA and mtDNA cox2 genes. Third-stage larvae (L3) of Anisakis typica occurred at low prevalence (P = 10% and 8%, respectively) in the viscera of Selar crumenophthalmus and Trichiurus lepturus, while Hysterothylacium amoyense occurred in the viscera of Sardinella fimbriata (P = 1%) and the viscera and muscle of Harpadon nehereus (P = 32%) and T. lepturus (P = 76%). Lappetascaris sp. Type A L3 occurred in the mantle of the squid Uroteuthis duvaucelii (P = 11%). Anisakis and Lappetascaris species, and H. amoyense were firstly identified in the Bay of Bengal. The potentially zoonotic A. typica was only found in fish viscera. Hysterothylacium amoyense and Lappetascaris sp., both generally regarded as non-zoonotic, occurred at low prevalence in the muscle or mantle of fish or squid, respectively. Since consumption of raw or lightly processed seafood seems to be rare in Bangladesh, the risk of acquiring anisakidosis from consuming fishery products from off Bangladesh appears to be low. Due to its reddish appearance, the visual presence of H. amoyense larvae in fish flesh may represent a food quality issue.

Relative risk scores generated from laboratory specificity tests predict non-target impacts of Microctonus spp. parasitoids in the field

A ‘relative risk score’ approach to help determine the potential impact of biological control agents on non-target species, previously proposed for weed biocontrol agents and aphid parasitoids, was examined in a retrospective study for Microctonus spp. parasitoids introduced to control pest weevils in New Zealand. ‘Relative risk scores’ (% parasitism for non-target weevil species/% parasitism for target weevil species) were calculated for 20 weevil (New Zealand adventive and indigenous) species and 3 introduced (New Zealand) Microctonus biocontrol taxa (Microctonus aethiopoides Moroccan biotype, Microctonus aethiopoides Irish biotype,and Microctonus hyperodae), based on previously published no-choice host range laboratory testing. Field hosts for each parasitoid and host combination were also examined through an extensive literature review and targeted field surveys. Strong correlations between ‘relative risk scores’ for no-choice laboratory assays and field host binary values (host: yes or no) were obtained for each Microctonus/weevil dataset, but there was no threshold score indicating that the approach cannot be relied upon to predict parasitoid field host ranges with a high degree of certainty. A second analysis that categorized weevil hosts as ‘major field hosts’, if literature records indicated high (≥10%) levels of parasitism in the field, showed a clearer relationship between relative risk score and the probability of a weevil being a major field host. There were no observations of a weevil being a major field host when the relative risk score value was <0.26. There was only one observation of a weevil not being a major field host where the relative risk score was >0.33. This nevertheless, indicates that the approach can mistakenly exclude some acceptable agents that would be host specific in the field. We conclude that this approach could potentially be used to assist risk assessment when introducing Microctonus spp. biocontrol agents, but other factors need to be assessed concurrently to reliably assess risk.

Modeling the consequences of the dikaryotic life cycle of mushroom-forming fungi on genomic conflict.

Generally, sexual organisms contain two haploid genomes, one from each parent, united in a single diploid nucleus of the zygote which links their fate during growth. A fascinating exception to this is Basidiomycete fungi, where the two haploid genomes remain separate in a dikaryon, retaining the option to fertilize subsequent monokaryons encountered. How the ensuing nuclear competition influences the balance of selection within and between individuals is largely unexplored. We test the consequences of the dikaryotic life cycle for mating success and mycelium-level fitness components. We assume a trade-off between mating fitness at the level of the haploid nucleus and fitness of the fungal mycelium. We show that the maintenance of fertilization potential by dikaryons leads to a higher proportion of fertilized monokaryons, but that the ensuing intradikaryon selection for increased nuclear mating fitness leads to reduced mycelium fitness relative to a diploid life cycle. However, this fitness reduction is lower compared to a hypothetical life cycle where dikaryons can also exchange nuclei. Prohibition of fusion between dikaryons therefore reduces the level of nuclear parasitism. The number of loci influencing fitness is an important determinant of the degree to which average mycelium-level fitness is reduced. The results of this study crucially hinge upon a trade-off between nucleus and mycelium-level fitness. We discuss the evidence for this assumption and the implications of an alternative that there is a positive relationship between nucleus and mycelium-level fitness.

Nutritional status, intestinal parasitic infections, and socio-environmental conditions in Mbyá-guaraní children: The current situation in communities in central Misiones, Argentina.

Our previous research in Mbyá-guaraní communities of central Misiones showed high levels of growth stunting and intestinal parasites in children, as well as associations between these variables and deficient sanitary conditions. New studies were necessary to update the present health status of the previously studied Mbyá populations after around two decades. Therefore, we evaluated the current nutritional status, intestinal parasites, and socio-environmental conditions among Mbyá-guaraní children from these communities. Body weight and height of 102 individuals (aged 2-14) were measured and nutritional status was estimated according to the World Health Organization criteria. Serial fecal samples and anal swabs were analyzed from 75 children (aged 1-14). Socio-environmental data were obtained from questionnaires. The prevalence of undernutrition was 31.4% and excess of weight was 10.8%. The prevalence of stunting and of overweight reached 30.4% and 8.8%, respectively. About 85% of the children were infected with at least one of the 14 species identified, and around 44% had multiple parasite infections. The most prevalent species were Enterobius vermicularis and hookworms. Among undernourished children, 88.2% were parasitized by at least one of the potentially pathogenic species detected. Most of the families lived in overcrowded conditions in precarious houses, defecated in latrines, and consumed well water. A higher risk of parasitosis was associated with the source of drinking water. Although the prevalence of undernutrition and intestinal parasites decreased compared with our previous studies, we still observed the coexistence of stunting, excess weight, and parasitic infections, in a context of socio-environmental vulnerability.

Genetic Polymorphism of Merozoite Surface Protein-2 (MSP-2) in Plasmodium falciparum Isolates from Endemic Sub-Counties, A Case Study in Kisii County, Kenya

Background: Despite a lot of efforts being put in place globally to reduce malaria burden, malaria is still one of the major public health problem. P. falciparum analysis of the Msp2 gene gives paramount evidence in the evaluation of malaria epidemiology to assist in the ongoing malaria control and elimination programs. Therefore this study aimed at examining genetic polymorphism of msp-2 gene of P. falciparum and its multiplicity of infection (MOI) from endemic Sub-Counties in Kisii County, Kenya.&#x0D; Methodology: Dried blood spots were collected from 249 study participants who were positive for P. falciparum parasite in endemic Sub – Counties in Kisii County from January to April 2021. Parasites density/μl of blood was calculated by multiplying the number of parasites counted and 8000 white cells/μl then dividing by number of white cells counted. Parasite level was considered low if the parasite/μl of blood was &lt; 500, moderate 501 ≤ 5000 and high if it was &gt; 5000 Parasites DNA was extracted using chelex-100® method and nested PCR for amplification followed by fragment analysis using gel electrophoresis.&#x0D; Results: 246 samples were identified with msp2 alleles where 94% belonged to 3D7 and 83% belonged to FC27. 40 different polymorphic alleles were identified where 13 belonged to FC27 and 27 belonging to 3D7. 86% isolates had multiple msp2 alleles where the Multiplicity of infection (MOI) overall mean was 2.75.&#x0D; Conclusion: The study isolates showed high genetic polymorphism. Therefore, this suggests that there is high local malaria transmission, meaning there is failure to the scale up of malaria control interventions in the endemic areas of the County.