Immunization of Nile tilapia (Oreochromis niloticus) Broodstock With Tilapia Lake Virus (TiLV) Inactivated Vaccines Elicits Protective Antibody and Passive Maternal Antibody Transfer

Tilapia lake virus (TiLV), a major pathogen of farmed tilapia, is known to be vertically transmitted. Here, we hypothesize that Nile tilapia (Oreochromis niloticus) broodstock immunized with a TiLV inactivated vaccine can mount a protective antibody response and passively transfer maternal antibodies to their fertilized eggs and larvae. To test this hypothesis, three groups of tilapia broodstock, each containing 4 males and 8 females, were immunized with either a heat-killed TiLV vaccine (HKV), a formalin-killed TiLV vaccine (FKV) (both administered at 3.6 ×106 TCID50 per fish), or with L15 medium. Booster vaccination with the same vaccines was given 3-weeks later, and mating took place 1 week thereafter. Broodstock blood sera, fertilized eggs and larvae were collected from 6-14 weeks post-primary vaccination for measurement of TiLV-specific antibody (anti-TiLV IgM) levels. In parallel, passive immunization using sera from the immunized female broodstock was administered to naïve tilapia juveniles to assess if antibodies induced in immunized broodstock were protective. The results showed that anti-TiLV IgM was produced in the majority of both male and female broodstock vaccinated with either the HKV or FKV and that and that these antibodies could be detected in the fertilized eggs and larvae from vaccinated broodstock. Higher levels of maternal antibody were observed in fertilized eggs from broodstock vaccinated with HKV than those vaccinated with FKV. Low levels of TiLV-IgM were detected in some of the 1-3-day old larvae but were undetectable in 7-14-day old larvae from the vaccinated broodstock, indicating a short persistence of TiLV-IgM in larvae. Moreover, passive immunization proved that antibodies elicited by TiLV vaccination were able to confer 85% to 90% protection against TiLV challenge in naïve juvenile tilapia. In conclusion, immunization of tilapia broodstock with TiLV vaccines could be a potential strategy for the prevention of TiLV in tilapia fertilized eggs and larvae, with HKV appearing to be more promising than FKV for maternal vaccination.

on Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae)

A study was undertaken on the ovicidal and larval repellent activity of Tagetes erecta leaf and flower extracts on Rhipicephalus sanguineus (Latreille, 1806), an important tick species in the world from an economic and medical point of view. Ethanol and methanol extracted plant products tested against the eggs and larvae of R. sanguineus indicated that the ethanol extract of flower had maximum ovicidal activity (86.1%), followed by the ethanol extract of leaf (75%) at 25 mg ml-1 concentration. In all analyses, the homogeneity of variance was significant. The probit analysis clearly indicated that the ethanol extract of the flower has a higher ability to kill the eggs. In the case of larval repellency tested, both extracts of leaf showed the highest repellency (83%) at 2.5 mg ml-1. Significant tick repellency (> 90%) was found in both methanol and ethanol extracts of flower at 2.5 mg ml-1. GC-MS analysis of extracts revealed the presence of bioactive insecticidal compounds such as yangambin, cyclohexane and neophytadine.

Evaluation Efficacy and Persistence of Some Volatile Plant Oils on Immature Stages of Galleria mellonella (L.)

The Experiment was carried out to measure the effect of four natural plant oils (namely: Cinnamonium zeylanicum L., Syzygium aromatic L., Citrus aurantium amara, and Lavandula spica) on controlling the greater wax moth and their ability to persist. The methodology included collecting and rearing the greater wax moth under laboratory conditions to be able to isolate the target tested stages. The immature stages (eggs and larvae) of the experiment moth were exposed to fumes of tested oils (50 µl/500 ml) to calculate hatchability and mortality percentage. The results were clear that fumes of C. zeylanicum and S. aromatic were caused 100% unhatching eggs after zero time as the same recorded by comparable compound (paradix) and able to persist their effect at the closed and limited zone for 60 days. On another side, C. zeylanicum and S. aromat were affected on last larval instars and emerged adults. The accumulative effect was appeared in the case of treatment by C. zeylanicum which was caused sterility to emerged adults and reduced eggs deposition to zero. The data indicated that some natural product compounds could be used as an alternative way of control insect pests.

The Neglected Angio-Neurotrophic Parasite Gurltia Paralysans (Nematoda: Angiostrongylidae): Northernmost South American Distribution, Current Knowledge, and Future Perspectives

Gurltia paralysans is a rare metastrongyloid nematode in South America that has begun to gain relevance in feline internal medicine as a differential diagnosis of progressive degenerative myelopathy disorders. The parasite life cycle has not been fully elucidated but probably involves invertebrate gastropod fauna as obligate intermediate hosts; thus, G. paralysans remaining an extremely neglected parasitosis. Feline gurltiosis intra vitam diagnosis is highly challenging due to lack of evidence in the excretion of G. paralysans eggs and larvae, neither in feces nor in other body secretions because environmental stages and the transmission route of the parasite remain unknown. Unfortunately, no experimental trials for the treatment of feline gurltiosis have been conducted to date. However, there are some reports of the successfully antiparasitic drugs used with different effectiveness and clinical improvement results in diagnosed cats. Further studies are needed to evaluate the parasite occurrence among domestic cats and the neotropical wild felid species distributed within Colombia in addition to the gastropod fauna that may harbor the developing larvae (L1–L3) stages of this underestimated parasite.

Improving the Knowledge on Distribution, Food Preferences and DNA Barcoding of Natura 2000 Protected Species Paracossulus thrips (Lepidoptera, Cossidae) in Romania

Paracossulus thrips (Lepidoptera, Cossidae) is one of the locally distributed and endangered species. In Europe, it is also one of the few protected moth species, through Annexes II and IV of the Council Directive 92/43/EEC, Annex II of the Bern Convention. To date, little is known about the biology and ecology of this species. Our study was conducted in Transylvania, Romania. Romania hosts some of the strongest populations of the species in the European region. As part of the study, we conducted field observations, vegetation analyses, and genetic analyses. In our paper, we show the habitat types where we encounter P. thrips in Transylvania and confirm Phlomis tuberosa as a host plant. Furthermore, a piece of important information for habitat conservation is given. In this paper, we present the eggs and larvae of P. thrips, the first DNA barcoding sequences, and four new populations of P. thrips in Romania. Our study provides baseline knowledge about the biology and ecology of P. thrips, which is important for conservation and establishing management measures.

A Field Efficacy Evaluation of In2Care Mosquito Traps in Comparison with Routine Integrated Vector Management at Reducing Aedes aegypti

ABSTRACT Aedes aegypti is the predominant vector of dengue, chikungunya, and Zika viruses. This mosquito is difficult to control with conventional methods due to its container-inhabiting behavior and resistance to insecticides. Autodissemination of pyriproxyfen (PPF), a potent larvicide, has shown promise as an additional tool to control Aedes species in small-scale field trials. However, few large-scale field evaluations have been conducted. We undertook a 6-month-long large-scale field study to compare the effectiveness and operational feasibility of using In2Care Mosquito Traps (In2Care Traps, commercially available Aedes traps with PPF and Beauveria bassiana) compared to an integrated vector management (IVM) strategy consisting of source reduction, larviciding, and adulticiding for controlling Ae. aegypti eggs, larvae, and adults. We found that while the difference between treatments was only statistically significant for eggs and larvae (P < 0.05 for eggs and larvae and P > 0.05 for adults), the use of In2Care Traps alone resulted in 60%, 57%, and 57% fewer eggs, larvae, and adults, respectively, collected from that site compared to the IVM site. However, In2Care Trap deployment and maintenance were more time consuming and labor intensive than the IVM strategy. Thus, using In2Care Traps alone as a control method for large areas (e.g., >20 ha) may be less practical for control programs with the capacity to conduct ground and aerial larviciding and adulticiding. Based on our study results, we conclude that In2Care Traps are effective at suppressing Ae. aegypti and have the most potential for use in areas without sophisticated control programs and within IVM programs to target hotspots with high population levels and/or risk of Aedes-borne pathogen transmission.

Exotic predators are not better biocontrol agents: the harlequin ladybird is not the most voracious in Mexico

The use of exotic species for pest biocontrol has been a common pathway for introduction and dispersal of invasive species that may have undesired outcomes. Biocontrol agents are believed to be a less damaging alternative than pesticides, but some species may also prey on or parasitize native species or outcompete them for resources. The harlequin ladybird (Harmonia axyridis) is a well-known biocontrol agent originally from Asia that has established invasive populations in 59 countries around the globe. Harlequin ladybirds are generalist predators that in addition to pests prey on an array of different species including other coccinelids’ eggs and larvae. In Mexico, native ladybirds that share ecological requirements with harlequin ladybirds are at risk of being outcompeted and predated upon. The aim of our study was to compare the foraging efficiency of harlequin ladybirds against three species of native coccinelids when preying on aphids. We investigated the foraging behaviour of ladybirds alone and in pairs with a conspecific, a native heterospecific or an exotic heterospecific. We found that the native Cycloneda sanguinea was the species that consumed the most aphids, while Hippodamia convergens was the fastest to find and consume each aphid. Harlequin ladybirds and H. convergens consumed the same number of aphids while P. vittigera consumed less. Conspecific competition was stronger than heterospecific competition. We discuss the suitability of using the exotic invasive harlequin ladybird for aphid biocontrol in comparison with native coccinelids.

Sanitary parasitological and sanitary–bacteriological condition of the soil in the astrakhan region

This article analyzes the sanitaryparasitological and sanitarybacteriological state of the soil of the Astrakhan region for 2015 to 2019. In total, 7587 soil samples taken from various environmental objects were studied, and 18.197 studies have been performed. Of the samples, 333 (4.4%) samples did not meet the hygiene standards. For parasitic purity, 4566 (60.2%) soil samples were examined, and 9132 (50.2%) studies have been performed. The largest number of soil samples were collected and examined in 2015 and 2016, which amounted to 943 (20.7%) in 2015 and 1046 (22.9%) in 2016. The number of samples that do not meet hygienic standards was 62 (6.6%) in 2015 and 91 (8.7%) in 2016. In 2015, the positive findings were helminthiasis caused by unfertilized eggs of Ascaris lumbricoides (4 [0.5%]), eggs of Toxocara canis (37 [3.9%]), and larvae of Strongyloides stercoralis (21 [2.2%]). For microbiological indicators, the largest number of soil samples were collected and examined in 2019 and amounted to 694 (23.0%), of which positive findings in the form of common coliform bacteria of Escherichia coli amounted to six (0.9%). Studies for bacteriological indicators in 2016 have used 662 (21.9%) samples, which is 0.9 times less than the samples taken in 2019. The sanitary condition of the soil of the Astrakhan region remains stably tense, as evidenced by positive findings in the form of eggs and larvae of helminths, as well as pathogenic bacteria of Escherichia coli. The presence of ascarid eggs, toxocars, and strongylid larvae in the soil indicates contamination of these objects with the feces of infected people and animals. The presence of coliform bacteria of Escherichia coli in the soil also indicates contamination with the feces of sick people.

Effect of hot-water immersion on eggs and larvae of Anastrepha grandis (Macquart, 1846) (Diptera: Tephritidae) “in vitro” and on squash (Cucurbita moschata Duchesne, 1786)

There are risks involved in the production and exportation of fruit fly hosts due to the possible spread of tephritid pests during distribution. Anastrepha grandis attacks cucurbit fruits and is considered an A1 quarantine pest in many countries. The objective of this study was to evaluate the effect of hot water treatment on the eggs and larvae of A. grandis in vitro, and on ‘Atlas’ squash (Cucurbita moschata). The eggs and third-instar larvae of A. grandis were exposed to hot water at temperatures of 42.0, 44.0, 46.0, 46.5, 47.0, 47.5, 48.0, 49.0 and 50.0 (± 0.5) °C for durations of 0 (control), 10, 20, 30 and 60 minutes. Water temperatures of at least 44 °C affected the in vitro larval eclosion of A. grandis during all exposure times. No adults were obtained when in vitro A. grandis larvae were treated at 49 °C and 50 °C at all exposure times and, 48 °C for 30 and 60 minutes. No adults were obtained when squashes infested with A. grandis eggs or larvae were treated at temperatures of 49 °C and 50 °C during any exposure time, as well as subjected to 48 °C for 20 minutes. Anastrepha grandis larvae were slightly more susceptible to hydrothermal treatment than eggs in squashes. Hot water treatment applies at a temperature of 48 °C for 20 minutes is an effective phytosanitary treatment for squashes cv. Atlas infested with eggs and larvae of A. grandis.