Disease and the Extended Phenotype: Parasites Control Host Performance and Survival through Induced Changes in Body Plan

BACKGROUND: By definition, parasites harm their hosts. However, some forms of parasite-induced alterations increase parasite transmission between hosts, such that manipulated hosts can be considered extensions of the parasite's phenotype. While well accepted in principle, surprisingly few studies have quantified how parasite manipulations alter host performance and survival under field and laboratory conditions. METHODOLOGY/PRINCIPAL FINDINGS: By interfering with limb development, the trematode Ribeiroia ondatrae causes particularly severe morphological alterations within amphibian hosts that provide an ideal system to evaluate parasite-induced changes in phenotype. Here, we coupled laboratory performance trials with a capture-mark-recapture study of 1388 Pacific chorus frogs (Pseudacris regilla) to quantify the effects of parasite-induced malformations on host locomotion, foraging, and survival. Malformations, which affected ~50% of metamorphosing frogs in nature, caused dramatic reductions in all measures of organismal function. Malformed frogs exhibited significantly shorter jumping distances (41% reduction), slower swimming speeds (37% reduction), reduced endurance (66% reduction), and lower foraging success relative to infected hosts without malformations. Furthermore, while normal and malformed individuals had comparable survival within predator-free exclosures, deformed frogs in natural populations had 22% lower biweekly survival than normal frogs and rarely recruited to the adult population over a two-year period. CONCLUSIONS/SIGNIFICANCE: Our results highlight the ability of parasites to deeply alter multiple dimensions of host phenotype with important consequences for performance and survival. These patterns were best explained by malformation status, rather than infection per se, helping to decouple the direct and indirect effects of parasitism on host fitness.Brett A. Goodman and Pieter T. J. Johnso

Reversal to air-driven sound production revealed by a molecular phylogeny of tongueless frogs, family Pipidae

<p>Abstract</p> <p>Background</p> <p>Evolutionary novelties often appear by conferring completely new functions to pre-existing structures or by innovating the mechanism through which a particular function is performed. Sound production plays a central role in the behavior of frogs, which use their calls to delimit territories and attract mates. Therefore, frogs have evolved complex vocal structures capable of producing a wide variety of advertising sounds. It is generally acknowledged that most frogs call by moving an air column from the lungs through the glottis with the remarkable exception of the family Pipidae, whose members share a highly specialized sound production mechanism independent of air movement.</p> <p>Results</p> <p>Here, we performed behavioral observations in the poorly known African pipid genus <it>Pseudhymenochirus </it>and document that the sound production in this aquatic frog is almost certainly air-driven. However, morphological comparisons revealed an indisputable pipid nature of <it>Pseudhymenochirus </it>larynx. To place this paradoxical pattern into an evolutionary framework, we reconstructed robust molecular phylogenies of pipids based on complete mitochondrial genomes and nine nuclear protein-coding genes that coincided in placing <it>Pseudhymenochirus </it>nested among other pipids.</p> <p>Conclusions</p> <p>We conclude that although <it>Pseudhymenochirus </it>probably has evolved a reversal to the ancestral non-pipid condition of air-driven sound production, the mechanism through which it occurs is an evolutionary innovation based on the derived larynx of pipids. This strengthens the idea that evolutionary solutions to functional problems often emerge based on previous structures, and for this reason, innovations largely depend on possibilities and constraints predefined by the particular history of each lineage.</p

Evaluating patterns and factors related to sleep disturbances in prostate cancer patients

Prostate cancer patients may experience disturbed sleep as a result of their diagnosis or treatment. This study sought to evaluate disturbed sleep and excessive daytime sleepiness in newly diagnosed patients and those receiving androgen deprivation therapy (ADT). This study was conducted with 74 patients. Subjective data using the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) and actigraphy data on ADT/ADT-naïve patients were collected. The prevalence of poor sleep quality, determined from PSQI and ESS scores, was 50% and 16.7% respectively. Those on ADT (n = 20) had poorer sleep quality as determined by significantly higher PSQI scores (70 vs. 40% scoring > 5) and were more likely to have poor sleep quality, sleep latency, and sleep efficiency than ADT-naïve patients (n = 40). Actigraphy data showed that ADT patients slept significantly longer (7.7 vs. 6.8 h), experienced a higher Fragmentation Index (48.3 vs. 37.4%), and had longer daytime nap duration (64.1 vs. 45.2 min) than ADT-naïve patients. The use of objective measures such as actigraphy in the clinical arena is recommended and may be used as a valuable tool for research into sleep assessment in prostate cancer patients

Development of a Sexual Quality of Life Questionnaire for Men-Who-Have-Sex-With-Men With Prostate Cancer

Background: Prostate cancer (PCa) is often diagnosed early with prolonged survival, which makes sexual quality of life (QoL) an increasingly important treatment consideration, but existing QoL questionnaires have limited applicability for men who-have-sex-with-men (MSM) beyond penile erections and penetrative sex. Aim: We aimed to create a validated survey instrument for assessing a variety of sexual activities beyond penile insertive sex for MSM after PCa treatment. Methods: Based on our previously published survey findings, we have generated a prototype questionnaire with 13 different domains, reviewed by both healthy MSM and pilot-tested by MSM treated for PCa. Outcomes: We report here on progress in developing the questionnaire and demonstrate the complexity of MSM sexual side effects resulting from PCa treatment(s). Results: Statistical analysis of 204 responses from MSM treated for PCa showed that each domain performed well individually (Cronbach's alpha coefficients ranged from 0.80 to 0.95; item-total correlations ranged from 0.16 to 0.89), with many significant intercorrelations between the domains (ranged from -0.048 to 0.93). Clinical Implications: The questionnaire can contribute to clinical diagnosis and treatment decisions that best fit the preferred sexual practices of individual MSM. Strengths & Limitations: The current questionnaire considers a much broader repertoire of MSM's sexual practices and preferences than other currently available questionnaires. The high intercorrelations between the many parameters demonstrate that problems in one domain can affect other domains. This preliminary analysis warrants further exploration with a larger sample size. Conclusions: Once validated our questionnaire should help develop tailored psychosocial supports for MSM experiencing sexual dysfunction after PCa treatment and help newly diagnosed MSM with PCa make treatment decisions informed by their preferred sexual practices. Wibowo E, Dowsett GW, Nelson CJ, et al. Development of a Sexual Quality of Life Questionnaire for Men-Who-Have-Sex-With-Men With Prostate Cancer. Sex Med 2021;XX:XXXXXX