Characterization of insect stains produced by Dermestes maculatus De Greer (Coleoptera: Dermestidae) resulting from interactions with human blood.

Insect stains produced by adult Dermestes maculatus were characterized during interactions with human blood. Beetles were offered wet or dried blood positioned on ceramic tiles under laboratory conditions. Despite a life history strategy geared toward consumption of dried food stuffs, adult beetles interacted with wet blood more frequently than dried and produced more insect stains after ingesting wet blood. Most (> 95%) of the insect stains produced were the result of fecal elimination. These stains varied in morphologies but were consistently tan/light, black/grey, or red in color; were round to amorphous in shape; and frequently possessed tails. Tailed stains typically were tadpole-shaped or long and tapering from the stain body, yielding Ltl/Lb ratios greater than 1. Tails were the result of beetle locomotion while defecating. Human blood was detected in defecatory stains when using ABA Hematrace® lateral flow assays. When beetles interacted with dried blood, the bloodstains were most often modified due to physical disruption rather than feeding activity. This yielded flaking or dislodgement of the original stains. Within a forensic context, it is unknown whether D. maculatus interacts with any type of bloodstains at a crime scene.

The effect of postmortem penetrative trauma on oviposition behavior of Calliphora vicina.

Flies in the family Calliphoridae are purported to demonstrate a strong attraction to and preferential colonization of wounds when present on human corpses or carrion. This well-circulated concept in Forensic Entomology is based on surprisingly few empirical studies that have examined the oviposition behavior of necrophagous Diptera toward wounds of vertebrate animals. In the present study, the oviposition behavior of Calliphora vicina toward piglets inflicted with postmortem sharp force trauma was examined during a 10-h test period under controlled laboratory conditions and in an outdoor urban environment. Three species of flies (C. vicina, C. livida and Cynomya cadaverina) deposited eggs on wounded and non-wound piglets during the field studies, although more than 80% of all eggs laid were by C. vicina regardless of wound status. For all species, oviposition occurred predominately on the head, including in eyes, ears, nose and mouth, and less frequently in other locations on the body. Eggs were never found in or near wounds. Similar oviposition patterns were displayed by C. vicina under laboratory conditions, with the exception for limited egg deposition in wounds under overcrowded conditions. In this latter scenario, egg deposition represented only 0.14% of the total reproductive output of adult flies. The findings do not support the contention that calliphorids preferentially oviposit in wounds resulting from sharp force penetrating trauma.

The National Conference on Health Disparities Student Research Forum.

The annual National Conference on Health Disparities (NCHD) was launched in 2000. It unites health professionals, researchers, community leaders, and government officials, and is a catalyzing force in developing policies, research interventions, and programs that address prevention, social determinants, health disparities, and health equity. The NCHD Student Research Forum (SRF) was established in 2011 at the Medical University of South Carolina to build high-quality biomedical research presentation capacity in primarily underrepresented undergraduate and graduate/professional students. This paper describes the unique research training and professional development aspects of the NCHD SRF. These include guidance in abstract development, a webinar on presentation techniques and methods, a vibrant student-centric conference, and professional development workshops on finding a mentor and locating scholarship/fellowship funding, networking, and strategies for handling ethical issues in research with mentors. Between 2011 and 2018, 400 undergraduate and graduate/professional students participated in the NCHD SRF. Most students were women (80.5%). Approximately half were African American or black (52.3%), 18.0% were white, and 21.3% were of Hispanic/Latinx ethnicity. The NCHD SRF is unique in several ways. First, it provides detailed instructions on developing a scientific abstract, including content area examples. Second, it establishes a mandatory pre-conference training webinar demonstrating how to prepare a scientific poster. Third, it works with the research mentors, faculty advisors, department chairs, and deans to help identify potential sources of travel funding for students with accepted abstracts. These features make the NCHD SRF different from many other conferences focused on students' scientific presentations.

Occupational exposure to severe acute respiratory coronavirus virus 2 (SARS-CoV-2) and risk of infection among healthcare personnel.

OBJECTIVE: To assess the rate and factors associated with healthcare personnel (HCP) testing positive for severe acute respiratory coronavirus virus 2 (SARS-CoV-2) after an occupational exposure. DESIGN: Retrospective cohort study. SETTING: Academic medical center with sites in Minnesota, Wisconsin, Arizona, and Florida. PARTICIPANTS: HCP with a high or medium risk occupational exposure to a patient or other HCP with SARS-CoV-2. METHODS: We reviewed the records of HCP with significant occupational exposures from March 20, 2020, through December 31, 2020. We then performed regression analysis to assess the impact of demographic and occupational variables to assess their impact on the likelihood of testing positive for SARS-CoV-2. RESULTS: In total, 2,253 confirmed occupational exposures occurred during the study period. Employees were the source for 57.1% of exposures. Overall, 101 HCP (4.5%) tested positive in the postexposure period. Of these, 80 had employee sources of exposure and 21 had patient sources of exposure. The postexposure infection rate was 6.2% when employees were the source, compared to 2.2% with patient sources. In a multivariate analysis, occupational exposure from an employee source had a higher risk of testing positive compared to a patient source (odds ratio [OR], 3.22; 95% confidence interval [CI], 1.72-6.04). Sex, age, high-risk exposure, and HCP role were not associated with an increased risk of testing positive. CONCLUSIONS: The risk of acquiring coronavirus disease 2019 (COVID-19) following a significant occupational exposure has remained relatively low, even in the prevaccination era. Exposure to an infectious coworker carries a higher risk than exposure to a patient. Continued vigilance and precautions remain necessary in healthcare settings.

Differential responses of adult Calliphora vicina to dry bloodstains on porous versus non-porous surface materials.

Necrophagous flies are presumed to feed on wet and dried blood at crime scenes, but no empirical information exists detailing fly interactions with dried bloodstains. In the present study, the foraging behavior of adult Calliphora vicina was characterized during interactions with dried bloodstains formed on a variety of porous, and non-porous materials that are commonly encountered in a household. Continuous digital recording and image analysis were used to monitor fly interactions with dried bloodstains and to determine mechanisms of stain modification. Flies displayed differential responses to bloodstains based on the porosity and topography of the surface material. For instance, blood that was not tightly adhered to the materials was flaked or dislodged by fly activity and was not consumed by the flies. On other non-porous surfaces, most stains were consumed following moistening by regurgitation. Feeding activity on such bloodstains frequently yielded partial, perimeter and skeletal stains. In contrast, adult flies rarely mechanically altered dried blood on porous fabrics and there was no evidence of modification due to feeding. Feeding avoidance behavior was observed due to tactile inhibition with blood dried on rough, uneven surfaces like cotton and denim.

Retention of Human Body Fluids in Adults of Calliphora vicina (Diptera: Calliphoridae).

Foraging by Calliphora vicina Robineau-Desvoidy often leads to a period of bubbling behavior, followed by either deposition of the regurgitate onto surfaces or reuptake of the bubble. Eventually, the partially or undigested food is passed in the excreta forming fecal or defecatory stains on surfaces in which deposition occurs. This study examined the digestive artifacts (i.e., regurgitate and defecatory stains) formed following consumption of human blood and semen by adult flies in an attempt to determine the length of time the meal was retained in the crop. The morphological appearance of either type of stain appeared consistent with the color of blood or semen for 10-20 d after feeding. When tested with ABA Hematrace immunochromatographic strip assays, blood was detectable in at least 33% of fly artifacts 25 d after the initial consumption of blood. Similarly, semen was detected in nearly 34% of digestive artifacts 30 d after feeding on human semen when using ABA p30 cards. Human body fluids were also detected in fly artifacts when using RSID lateral flow assays, but a much lower percentage of artifacts tested positive for blood (4.9%) and semen (4.6%) 25-d postfeeding in comparison to ABA strip assays. The difference between the types of lateral flow assays appeared to be due to extraction efficiencies of the buffers used for isolation of blood or semen from the fly artifacts. The implications of these observations in reference to seasonal adaptations and to bloodstain pattern analysis at crime scenes are discussed.

Species richness and redundancy promote persistence of exploited mutualisms in yeast.

Mutualisms, or reciprocally beneficial interspecific interactions, constitute the foundation of many ecological communities and agricultural systems. Mutualisms come in different forms, from pairwise interactions to extremely diverse communities, and they are continually challenged with exploitation by nonmutualistic community members (exploiters). Thus, understanding how mutualisms persist remains an essential question in ecology. Theory suggests that high species richness and functional redundancy could promote mutualism persistence in complex mutualistic communities. Using a yeast system (Saccharomyces cerevisiae), we experimentally show that communities with the greatest mutualist richness and functional redundancy are nearly two times more likely to survive exploitation than are simple communities. Persistence increased because diverse communities were better able to mitigate the negative effects of competition with exploiters. Thus, large mutualistic networks may be inherently buffered from exploitation.

Characterization of Insect Stains Deposited by Calliphora vicina (Diptera: Calliphoridae) on Shirt Fabrics.

Despite the fact that necrophagous flies are known to alter bloodstains and create unique artifacts, no research has occurred to date that has examined the characteristics of insect stains on textiles or fabrics. This study represents the first effort to characterize artifacts produced by adult Calliphora vicina Robineau-Desvoidy deposited on a range of shirt fabrics that varied in type, color, orientation, and yarn tension. In general, artifact morphology on any type of fabric was distorted in comparison to those observed on smooth and/or nonporous surfaces in previous studies. Consequently, distinction of artifact type could only be made broadly as digestive artifacts and transfer patterns, in which the latter was predominantly detected as tarsal tracks. None of the artifacts displayed satellite stains typical of human bloodstains found on textiles. Wicking was evident on all fabrics but was most pronounced with dri wick and jersey knit polyester in comparison to cotton knit. Digestive artifacts on any colored fabric, but especially with green and yellow shirt samples, resembled the reported color, size, and morphology of bloodstains generated in laboratory studies on a range of fabrics. Unique digestive artifacts were also detected as small, black, and nearly spherical. These defecatory stains did not appear to wet or wick into any of the fabrics. Digestive artifacts and tarsal tracks differentially interacted with front face stitch loops of clothing fabrics to yield distinct stain patterns. The implications of these observations in reference to bloodstain pattern analysis at crime scenes are discussed.

Detection of fly artifacts from four species of necrophagous flies on household materials using immunoassays.

An immunoassay was previously developed as a technique to improve methods for detection and analysis of fly artifacts found at crime scenes. The dot blot assay utilized a polyclonal antiserum (anti-md3) based on a unique digestive cathepsin D found in cyclorrhaphous Diptera. In this study, artifacts produced by adults of Calliphora vicina, Cynomya cadaverina, Sarcophaga bullata, and Protophormia terraenovae were examined using the immunoassay to determine if insect-derived stains could be distinguished from a range of human body fluid stains. A lift technique was developed which permitted transfer of fly artifacts from test materials to filter paper for dot blot analyses. All species readily deposited artifacts on all test household materials regardless of diet consumed. Despite differences in texture and porosity of the household materials, artifacts of all species transferred to the filter paper. With all fly species, anti-md3 serum bound to artifacts produced after feeding on semen, blood, feces, urine, and saliva. By contrast, anti-md3 serum did not react with any of the human fluids tested, nor with any of the lifts from household materials not exposed to flies. There was no evidence of false positives with any of the fly species tested, regardless of diet consumed. There was also no indication of false negatives with any of the dot blot assays. These observations suggest that immunoassays using anti-md3 serum performed on a simple lift of suspected fly artifacts can be used effectively as a confirmatory assay to distinguish fly regurgitate and fecal stains from human body fluids.

Immunoassay detection of fly artifacts produced by several species of necrophagous flies following feeding on human blood.

Foraging behavior of necrophagous flies commonly leads to distortion of human bloodstains and production of artifacts that confound reconstruction efforts at crime scenes. Currently there is no reliable method for detection of fly-derived stains or distinction of the artifacts from human bloodstains. To overcome these deficiencies, a confirmatory test was developed based on immunological detection of cathepsin D found in digestive fluids of Musca domestica and Protophormia terraenovae. Anti-serum (anti-md3 serum) was generated toward a 17-amino acid synthetic peptide based upon predicted antigenic amino acid sequences for the propeptide and mature enzyme of cathepsin D proteinase from larvae of M. domestica. The serum was used to test the hypothesis that digestive artifacts produced by an array of necrophagous flies associated with human decomposition could be detected with the immunoassay. Anti-md3 serum was able to bind artifacts from 27 species of flies representing 9 families. The antiserum reacted with both regurgitate and defecatory stains, but not transfer patterns. Stains from 4 fly species displayed no reactivity with anti-serum in dot blot assays. Anti-md3 serum did not bind to either human or bovine blood stains on filter paper. However, when both types of blood were spiked with synthetic md3 peptide the antiserum was able to bind. Dot blot assays displayed positive reactions with stains produced from larvae and teneral adults of Sarcophaga bullata, and with artifacts as old as 7-years after deposition. These observations indicate that the immunoassay permits distinction of artifacts from a wide range of species from human bloodstains, from multiple development stages, and from artifacts that remain at crime scenes for many months to years after deposition. Further work is needed to determine whether the detection of fly artifacts using the antiserum is suitable for non-laboratory conditions.

Improving Undergraduate Life Science Education for the Biosciences Workforce: Overcoming the Disconnect between Educators and Industry.

The BioHealth Capital Region (Maryland, Virginia, and Washington, DC; BHCR) is flush with colleges and universities training students in science, technology, engineering, and mathematics disciplines and has one of the most highly educated workforces in the United States. However, current educational approaches and business recruitment tactics are not drawing sufficient talent to sustain the bioscience workforce pipeline. Surveys conducted by the Mid-Atlantic Biology Research and Career Network identified a disconnect between stakeholders who are key to educating, training, and hiring college and university graduates, resulting in several impediments to workforce development in the BHCR: 1) students are underinformed or unaware of bioscience opportunities before entering college and remain so at graduation; 2) students are not job ready at the time of graduation; 3) students are mentored to pursue education beyond what is needed and are therefore overqualified (by degree) for most of the available jobs in the region; 4) undergraduate programs generally lack any focus on workforce development; and 5) few industry-academic partnerships with undergraduate institutions exist in the region. The reality is that these issues are neither surprising nor restricted to the BHCR. Recommendations are presented to facilitate improvement in the preparation of graduates for today's bioscience industries throughout the United States.

Distinction of Fly Artifacts from Human Blood using Immunodetection.

Insect stains produced by necrophagous flies are indistinguishable morphologically from human bloodstains. At present, no diagnostic tests exist to overcome this deficiency. As the first step toward developing a chemical test to recognize fly artifacts, polyclonal antisera were generated in rats against three distinct antigenic sequences of fly cathepsin D-like proteinase, an enzyme that is structurally distinct in cyclorrhaphous Diptera from other animals. The resulting rat antisera bound to artifacts produced by Protophormia terraenovae and synthetic peptides used to generate the polyclonal antisera, but not with any type of mammalian blood tested in immunoassays. Among the three antisera, anti-md3 serum displayed the highest reactivity for fly stains, demonstrated cross-reactivity for all synthetic peptides representing antigenic sequences of the mature fly enzyme, and bound artifacts originating from the fly digestive tract. Further work is needed to determine whether the antisera are suitable for non-laboratory conditions.

Morphological Features of Regurgitate and Defecatory Stains Deposited by Five Species of Necrophagous Flies are Influenced by Adult Diets and Body Size.

The morphological characteristics of artifacts from five species of necrophagous flies were examined following feeding on several types of diets. Four types of insect stains were produced by each species: regurgitate, defecatory, translocation, and tarsal tracks. Regurgitate was the most frequent type deposited (70.9 ± 2.4%), followed by defecatory (19.8 ± 4.0%), tarsal tracks (8.6 ± 1.2%), and translocation (0.7 ± 0.1%). Artifact shapes, sizes, and color were highly variable and species and diet specific. Calliphora vicina and Sarcophaga bullata consistently deposited the largest artifacts after feeding, whereas Chrysomya rufifacies and Ch. megacephala produced more tarsal tracks than the other species examined. Artifacts with tails were infrequently observed (4.1 ± 0.6% of all stains) but occurred as either defecatory or regurgitate stains. The widely variable morphologies of all types of fly artifacts underscores the view that insect stains cannot be distinguished from human bloodstains based on morphology alone.

Insect Artifacts Are More than Just Altered Bloodstains.

The bases for forensic entomology are that insects and their arthropod relatives can serve as evidence in criminal, medical and civil legal matters. However, some of the very same species that provide utility to legal investigations can also complicate crime scenes by distorting existing body fluid evidence (e.g., bloodstains, semen, saliva) and/or depositing artifacts derived from the insect alimentary canal at primary or secondary crime scenes. The insect contaminants are referred to as insect stains, artifacts, specks or spots, and are most commonly associated with human bloodstains. This review will discuss the different types of insect artifacts that have been described from crime scenes and laboratory experiments, as well as examine insect contaminates (non-blood based artifacts, transfer patterns, meconium, and larval fluids) that have received little research or case attention. Methods currently used for distinguishing insect stains from human body fluids will also be discussed and compared to presumptive tests used for identification of human body fluids. Since all available methods have severe limitations, areas of new research will be identified for the purpose of development of diagnostic techniques for detection of insect artifacts.

First Record of the Larval Endoparasitoid Tachinaephagus zealandicus (Hymenoptera: Encyrtidae) From Fly Hosts Developing on Burnt Remains and in Pennsylvania.

Adults of the gregarious larval endoparasitoid Tachinaephagus zealandicus Ashmead (Hymenoptera: Encyrtidae) were collected from two species of carrion-inhabiting flies, Phormia regina Meigen (Diptera: Calliphoridae) and Hydrotaea aenescens Wiedemann (Muscidae), associated with the burnt remains of a domesticated pig, Sus scrofa L. (Artiodactyla: Suidae), during late summer in south central Pennsylvania. This represents the first reported occurrence of the wasp in the state and only the second in the mid-Atlantic region. Collection from P. regina is a new host record for T. zealandicus and also the first for this parasitoid being attracted to flies on burnt remains.

Mentoring Strategies and Outcomes of Two Federally Funded Cancer Research Training Programs for Underrepresented Students in the Biomedical Sciences.

The US is experiencing a severe shortage of underrepresented biomedical researchers. The purpose of this paper is to present two case examples of cancer research mentoring programs for underrepresented biomedical sciences students. The first case example is a National Institutes of Health/National Cancer Institute (NIH/NCI) P20 grant titled "South Carolina Cancer Disparities Research Center (SC CaDRe)" Training Program, contributing to an increase in the number of underrepresented students applying to graduate school by employing a triple-level mentoring strategy. Since 2011, three undergraduate and four graduate students have participated in the P20 SC CaDRe program. One graduate student published a peer-reviewed scientific paper. Two graduate students (50 %) have completed their master's degrees, and the other two graduate students will receive their degrees in spring 2015. Two undergraduate students (67 %) are enrolled in graduate or professional school (grad./prof. school), and the other graduate student is completing her final year of college. The second case example is a prostate cancer-focused Department of Defense grant titled "The SC Collaborative Undergraduate HBCU Student Summer Training Program," providing 24 students training since 2009. Additionally, 47 students made scientific presentations, and two students have published peer-reviewed scientific papers. All 24 students took a GRE test preparation course; 15 (63 %) have applied to graduate school, and 11 of them (73 %) are enrolled in grad./prof. school. Thirteen remaining students (54 %) are applying to grad./prof. school. Leveraged funding provided research-training opportunities to an additional 201 National Conference on Health Disparities Student Forum participants and to 937 Ernest E. Just Research Symposium participants at the Medical University of South Carolina.

Phylogenetic analysis of RAD-seq data: examining the influence of gene genealogy conflict on analysis of concatenated data.

One of the major issues in phylogenetic analysis is that gene genealogies from different gene regions may not reflect the true species tree or history of speciation. This has led to considerable debate about whether concatenation of loci is the best approach for phylogenetic analysis. The application of Next-generation sequencing techniques such as RAD-seq generates thousands of relatively short sequence reads from across the genomes of the sampled taxa. These data sets are typically concatenated for phylogenetic analysis leading to data sets that contain millions of base pairs per taxon. The influence of gene region conflict among so many loci in determining the phylogenetic relationships among taxa is unclear. We simulated RAD-seq data by sampling 100 and 500 base pairs from alignments of over 6000 coding regions that each produce one of three highly supported alternative phylogenies of seven species of Drosophila. We conducted phylogenetic analyses on different sets of these regions to vary the sampling of loci with alternative gene trees to examine the effect on detecting the species tree. Irrespective of sequence length sampled per region and which subset of regions was used, phylogenetic analyses of the concatenated data always recovered the species tree. The results suggest that concatenated alignments of Next-generation data that consist of many short sequences are robust to gene tree/species tree conflict when the goal is to determine the phylogenetic relationships among taxa.

Spatial characterization of proteolytic enzyme activity in the foregut region of the adult necrophagous fly, Protophormia terraenovae.

The spatial distribution of proteolytic enzymes in the adult foregut of Protophormia terraenovae was studied in the context of protein digestion and regurgitation. Based on substrate specificity, pH optima, and use of specific protease inhibitors, all adults tested displayed enzyme activity in the foregut consistent with pepsin, trypsin and chymotrypsin. Chymotrypsin-like and trypsin-like enzyme activity were detected in all gut fluids and tissues tested, with chymotrypsin displaying the highest activity in saliva and salivary gland tissue, whereas maximal trypsin activity was evident in the crop. Pepsin-like activity was only evident in crop fluids and tissues. The activity of all three enzymes was low or undetectable (pepsin) in the fluids and tissue homogenates derived from the esophagus and cardia of any of the adults assayed. Fed adult females displayed higher enzyme activities than fed males, and the activity of all three enzymes were much more prevalent in fed adults than starved. The pH optimum of the trypsin-like enzyme was between pH 7.0 and 8.0; chymotrypsin was near pH 8.0; and maximal pepsin-like activity occurred between pH 1.0 and 2.0. Regurgitate from fed adult females displayed enzyme activity consistent with the proteolytic enzymes detected in crop gut fluids. Enzymes in regurgitate were not derived from food sources based on assays of bovine liver samples. These latter observations suggest that adult flies release fluids from foregut when encountering dry foods, potentially as a means to initiate extra-oral digestion.