Natural variation in host feeding behaviors impacts host disease and pathogen transmission potential.

Animals ranging from mosquitoes to humans often vary their feeding behavior when infected or merely exposed to pathogens. These so-called "sickness behaviors" are part of the innate immune response with many consequences, including avoiding orally transmitted pathogens. Fully understanding the role of this ubiquitous behavior in host defense and pathogen evolution requires a quantitative account of its impact on host and pathogen fitness across environmentally relevant contexts. Here, we use a zooplankton host and fungal pathogen as a case study to ask if infection-mediated feeding behaviors vary across pathogen exposure levels and natural genetic variation in susceptibility to infection. Then, we connect these changes in behavior to pathogen transmission potential (spore yield) and fitness and growth costs to the host. Our results validate a protective effect of altered feeding behavior during pathogen exposure while also revealing significant variation in the magnitude of this response across host susceptibility and pathogen exposure levels. Across all four host genotypes, feeding rates were negatively correlated with susceptibility to infection and transmission potential. The most susceptible genotypes exhibited either strong anorexia, reducing food intake by 26%-42%, ("Standard") or pronounced hyperphagia, increasing food intake by 20%-54% ("A45"). Together, these results suggest that infection-mediated changes in host feeding behavior-which are traditionally interpreted as immunopathology- may in fact serve as crucial components of host defense strategies and warrant further investigation.

Patient Reported Outcome Measures of Health-Related Quality of Life and Asthenia after Thyroidectomy.

BACKGROUND: After thyroidectomy some patients experience a chronic fatigue syndrome called asthenia. The purpose of this study was to determine the post-operative health related quality of life (HRQOL) and risk of asthenia in patients undergoing thyroidectomy. METHODS: A single institution prospective observational cohort study of adults undergoing thyroidectomy from September 2016 to July 2019 with four HRQOL surveys: preoperative baseline, 2 wk-, 6 mo- and 12 mo-postoperatively. Patients were surveyed using the Short Form 36 version 2 and Brief Fatigue Inventory. Asthenia was defined as Brief Fatigue Inventory > 60 at 12 mo. HRQOL was compared between patients undergoing thyroid lobectomy (TL) or total thyroidectomy (TT) with benign (-B) or malignant (-Ca) final pathology. RESULTS: A total of 182 patients were included: 67 (37%) with TL-B, 32 (17%) with TL-Ca, 40 (22%) with TT-B, and 43 (24%) with TT-Ca. The incidence of asthenia was 42% for TT and 4% for TL. In the TL-B group, 2 patients (3%) developed asthenia, compared with 2 patients (6.25%) in the TL-Ca group, 14 patients (35%) in the TT-B group, and 21 (48.8%) in the TT-Ca group (P = 0.0001). The odds ratio of asthenia for TT compared to TL was 10.4 (95% CI 3.86-28.16) and for patients with malignancy compared to benign disease was 2.05 (95% CI 1.17-3.61). CONCLUSIONS: Patients undergoing TT have a higher risk of developing asthenia than those undergoing TL, particularly if the final pathology shows malignancy.

A high-throughput method to quantify feeding rates in aquatic organisms: A case study with Daphnia.

Food ingestion is one of the most basic features of all organisms. However, obtaining precise-and high-throughput-estimates of feeding rates remains challenging, particularly for small, aquatic herbivores such as zooplankton, snails, and tadpoles. These animals typically consume low volumes of food that are time-consuming to accurately measure.We extend a standard high-throughput fluorometry technique, which uses a microplate reader and 96-well plates, as a practical tool for studies in ecology, evolution, and disease biology. We outline technical and methodological details to optimize quantification of individual feeding rates, improve accuracy, and minimize sampling error.This high-throughput assay offers several advantages over previous methods, including i) substantially reduced time allotments per sample to facilitate larger, more efficient experiments; ii) technical replicates; and iii) conversion of in vivo measurements to units (mL-1 hr-1 ind-1) which enables broad-scale comparisons across an array of taxa and studies.To evaluate the accuracy and feasibility of our approach, we use the zooplankton, Daphnia dentifera, as a case study. Our results indicate that this procedure accurately quantifies feeding rates and highlights differences among seven genotypes.The method detailed here has broad applicability to a diverse array of aquatic taxa, their resources, environmental contaminants (e.g., plastics), and infectious agents. We discuss simple extensions to quantify epidemiologically relevant traits, such as pathogen exposure and transmission rates, for infectious agents with oral or trophic transmission.