Male Mating Competitiveness of a Wolbachia-Introgressed Aedes polynesiensis Strain under Semi-Field Conditions

Aedes polynesiensis is the primary mosquito vector of lymphatic filariasis (LF) in the island nations of the South Pacific. Control of LF in this region of the world is difficult due to the unique biology of the mosquito vector. A proposed method to control LF in the Pacific is through the release of male mosquitoes that are effectively sterile. In order for this approach to be successful, it is critical that the modified male mosquitoes be able to compete with wild type male mosquitoes for female mates. In this study the authors examined the mating competitiveness of modified males under semi-field conditions. Modified males were released into field cages holding field-collected, virgin females and field collected wild type males. The resulting proportion of eggs that hatched was inversely related to the number of modified males released into the cage, which is consistent with the hypothesized competitiveness of modified males against indigenous males. The outcome indicates that mass release of modified A. polynesiensis mosquitoes could result in the suppression of A. polynesiensis populations and supports the continued development of applied strategies for suppression of this important disease vector

The Genetic Links to anxiety and depression (GLAD) study: Online recruitment into the largest recontactable study of depression and anxiety

Background: Anxiety and depression are common, debilitating and costly. These disorders are influenced by multiple risk factors, from genes to psychological vulnerabilities and environmental stressors, but research is hampered by a lack of sufficiently large comprehensive studies. We are recruiting 40,000 individuals with lifetime depression or anxiety and broad assessment of risks to facilitate future research. Methods: The Genetic Links to Anxiety and Depression (GLAD) Study (www.gladstudy.org.uk) recruits individuals with depression or anxiety into the NIHR Mental Health BioResource. Participants invited to join the study (via media campaigns) provide demographic, environmental and genetic data, and consent for medical record linkage and recontact. Results: Online recruitment was effective; 42,531 participants consented and 27,776 completed the questionnaire by end of July 2019. Participants’ questionnaire data identified very high rates of recurrent depression, severe anxiety, and comorbidity. Participants reported high rates of treatment receipt. The age profile of the sample is biased toward young adults, with higher recruitment of females and the more educated, especially at younger ages. Discussion: This paper describes the study methodology and descriptive data for GLAD, which represents a large, recontactable resource that will enable future research into risks, outcomes, and treatment for anxiety and depression

Can the intake of antiparasitic secondary metabolites explain the low prevalence of hemoparasites among wild Psittaciformes?

Background: Parasites can exert selection pressure on their hosts through effects on survival, on reproductive success, on sexually selected ornament, with important ecological and evolutionary consequences, such as changes in population viability. Consequently, hemoparasites have become the focus of recent avian studies. Infection varies significantly among taxa. Various factors might explain the differences in infection among taxa, including habitat, climate, host density, the presence of vectors, life history and immune defence. Feeding behaviour can also be relevant both through increased exposure to vectors and consumption of secondary metabolites with preventative or therapeutic effects that can reduce parasite load. However, the latter has been little investigated. Psittaciformes (parrots and cockatoos) are a good model to investigate these topics, as they are known to use biological control against ectoparasites and to feed on toxic food. We investigated the presence of avian malaria parasites (Plasmodium), intracellular haemosporidians (Haemoproteus, Leucocytozoon), unicellular flagellate protozoans (Trypanosoma) and microfilariae in 19 Psittaciformes species from a range of habitats in the Indo-Malayan, Australasian and Neotropical regions. We gathered additional data on hemoparasites in wild Psittaciformes from the literature. We considered factors that may control the presence of hemoparasites in the Psittaciformes, compiling information on diet, habitat, and climate. Furthermore, we investigated the role of diet in providing antiparasitic secondary metabolites that could be used as self-medication to reduce parasite load. Results: We found hemoparasites in only two of 19 species sampled. Among them, all species that consume at least one food item known for its secondary metabolites with antimalarial, trypanocidal or general antiparasitic properties, were free from hemoparasites. In contrast, the infected parrots do not consume food items with antimalarial or even general antiparasitic properties. We found that the two infected species in this study consumed omnivorous diets. When we combined our data with data from studies previously investigating blood parasites in wild parrots, the positive relationship between omnivorous diets and hemoparasite infestation was confirmed. Individuals from open habitats were less infected than those from forests. Conclusions: The consumption of food items known for their secondary metabolites with antimalarial, trypanocidal or general antiparasitic properties, as well as the higher proportion of infected species among omnivorous parrots, could explain the low prevalence of hemoparasites reported in many vertebrates

Insemination rate of <i>A. polynesiensis</i> females after 24 h in field cages.

<p>Insemination rate of <i>A. polynesiensis</i> females after 24 h in field cages.</p

Assessment of <i>A. polynesiensis</i> CP male competitiveness in field cages.

<p>A; The results of Experiment A. B; The results of Experiment B. Females were considered to have produced a hatching brood when egg hatch was >10%. Circles and bars indicate the mean ± standard deviation for each male ratio. The trend line (dashed line) with 95% confidence intervals (dotted line) is generated based on observed values. Predicted values of compatibly mated broods (solid line) were calculated assuming equal competitiveness of the APA and CP males. R² value is fitted to the observed values. Females were scored according to the observed egg hatch rate as either ‘compatible mating’ (>10% egg hatch) or ‘incompatible mating’ (<10% egg hatch). ‘All broods’ is the average egg hatch resulting from both compatible and incompatible broods. The egg hatch rates are based upon combined oviposition of females within the same treatment field cages. Differing superscripted letters indicate significant differences. Experiment A (Wilcoxon Rank-Sum test, p<0.016, Bonferroni corrected); Experiment B (Wilxocon Rank-Sum test, p<0.01, Bonferroni corrected).</p

Box-plot showing the distribution of brood hatch rates for treatment groups from Experiment A and Experiment B.

<p>A; The results from experiment A. B; The results from experiment B. Median and 1^st (Q₁) and 3^rd (Q₃) quartiles of brood hatch rates for each of the CP:APA treatments. The whiskers of the box-plot represent 1.5*Q₁ and 1.5*Q₃ and circles represent outliers. Hatch categories; h = high (≥70%), i = intermediate (11–69%), l = low (≤10%).</p

Statement in Support of: “Virology under the Microscope—a Call for Rational Discourse”

[Extract] We, members of the Australasian Virology Society, agree with and support the statement entitled “Virology under the Microscope—a Call for Rational Discourse” (1). Like virologists everywhere, we have worked with scientist and clinician colleagues worldwide to develop knowledge, tests, and interventions which collectively have reduced the number of deaths due to COVID-19 and curtailed its economic impact. Such work adds to the extraordinary achievements resulting from virology research that have delivered vaccines and/or antivirals against a long list of diseases and global scourges, including AIDS, smallpox, and polio (1). We believe the question of the origin of SARS-CoV-2 should be approached with an open mind and in consideration of the best scientific evidence available. We concur with the view that the zoonosis hypothesis has the strongest supporting evidence (2–4), and this is a scenario that has been observed repeatedly in the past (5), including in Australia (6). Recent data strongly support the zoonosis hypothesis (7). We share the concern that emotive and fear-based dialogues in this area add to public confusion and can lead to ill-informed condemnation of virology research