Multicenter Assessment of Cryoanalgesia Use in Minimally Invasive Repair of Pectus Excavatum: A 20-center Retrospective Cohort Study.

OBJECTIVE: To assess the clinical implications of cryoanalgesia for pain management in children undergoing minimally invasive repair of pectus excavatum (MIRPE). BACKGROUND: MIRPE entails significant pain management challenges, often requiring high postoperative opioid use. Cryoanalgesia, which blocks pain signals by temporarily ablating intercostal nerves, has been recently utilized as an analgesic adjunct. We hypothesized that the use of cryoanalgesia during MIRPE would decrease postoperative opioid use and length of stay (LOS). MATERIALS AND METHODS: A multicenter retrospective cohort study of 20 US children's hospitals was conducted of children (age below 18 years) undergoing MIRPE from January 1, 2014, to August 1, 2019. Differences in total postoperative, inpatient, oral morphine equivalents per kilogram, and 30-day LOS between patients who received cryoanalgesia versus those who did not were assessed using bivariate and multivariable analysis. P value <0.05 is considered significant. RESULTS: Of 898 patients, 136 (15%) received cryoanalgesia. Groups were similar by age, sex, body mass index, comorbidities, and Haller index. Receipt of cryoanalgesia was associated with lower oral morphine equivalents per kilogram (risk ratio=0.43, 95% confidence interval: 0.33-0.57) and a shorter LOS (risk ratio=0.66, 95% confidence interval: 0.50-0.87). Complications were similar between groups (29.8% vs 22.1, P =0.07), including a similar rate of emergency department visit, readmission, and/or reoperation. CONCLUSIONS: Use of cryoanalgesia during MIRPE appears to be effective in lowering postoperative opioid requirements and LOS without increasing complication rates. With the exception of preoperative gabapentin, other adjuncts appear to increase and/or be ineffective at reducing opioid utilization. Cryoanalgesia should be considered for patients undergoing this surgery.

Upper Gastrointestinal Series in the Workup for Pediatric Gastrostomy Placement: Does it Delay Care?

INTRODUCTION: Upper gastrointestinal (UGI) series is often part of the workup prior to the placement of gastrostomy tubes in children. Prior studies have suggested UGI to be limited in utility and an extra financial burden. The goal of this study was to investigate the utility and cost of UGI studies. METHODS: A retrospective, case control study of patients aged < 18 y receiving gastrostomy tubes at a free-standing children's hospital between 2012 and 2017. Total costs were obtained from the Pediatric Health Information System. RESULTS: Six hundred eighty five patients underwent gastrostomy placement during the study period. UGI was obtained in 90.8% of patients; 23.6% of studies were abnormal. The most common abnormal findings were reflux (13.8%) and abnormal anatomy (5.8%). The median time to obtain a UGI was 0.82 d (interquartile range 0.22-1.05). Obtaining a UGI was associated with delayed care in 104 patients (15.2%). If a delay was encountered, median time was 2.47 d (interquartile range 1.86-2.99). Ladd's procedures were performed in 12 patients (1.7%) found to have malrotation on UGI. None of the 63 patients who did not undergo UGI required a Ladd's procedure. Patients that had a UGI did not experience an increase in overall length of stay (14.3 versus 15.6 d, excluding intensive care unit patients), operative time (34 versus 39 min), or a change in rate of operative complications (11.5% versus 14.3%). In addition, UGI did not have a significant impact on total adjusted costs ($49,844 versus $83,438 without UGI, P = 0.12) but did slightly increase total adjusted costs per day ($2212 versus $1999 without UGI, P = 0.01). CONCLUSIONS: UGI prior to gastrostomy placement in children rarely identified abnormal findings that changed the operative plan, was associated with delayed care in 15% of patients, and was associated with slightly increased costs per day. Further analyses to identify subsets of children that may benefit from routine UGI are warranted.

Providers' Perceptions Versus Practices Inform Pediatric Colorectal Enhanced Recovery After Surgery Implementation.

INTRODUCTION: There are many barriers to the implementation of an enhanced recovery after surgery (ERAS) pathway. The aim of this study was to compare surgeon and anesthesia perceptions with current practices prior to the initiation of an ERAS protocol in pediatric colorectal patients and to use that information to inform ERAS implementation. METHODS: This was a mixed method single institution study of barriers to implementation of an ERAS pathway at a free-standing children's hospital. Anesthesiologists and surgeons at a free-standing children's hospital were surveyed regarding current practices of ERAS components. A retrospective chart review was performed of 5- to 18-y-old patients undergoing colorectal procedures between 2013 and 2017, followed by the initiation of an ERAS pathway, and a prospective chart review for 18 mo postimplementation. RESULTS: The response rate was 100% (n = 7) for surgeons and 60% (n = 9) for anesthesiologists. Preoperative nonopioid analgesics and regional anesthesia were rarely used. Intraoperatively, 54.7% of patients had a fluid balance of <10 cc/kg/h and normothermia was achieved in only 38.7%. Mechanical bowel prep was frequently utilized (48%). Median nil per os time was significantly longer than required at 12 h. Postoperatively, 42.9% of surgeons reported that patients could have clears on postoperative day zero, 28.6% on postoperative day one, and 28.6% after flatus. In reality, 53.3% of patients were started on clears after flatus, with a median time of 2 d. Most surgeons (85.7%) expected patients to get out of bed once awake from anesthesia; however, median time that patients were out of bed was postoperative day one. While most surgeons reported frequent use of acetaminophen and/or ketorolac, only 69.3% received any nonopioid analgesic postoperatively, with only 41.3% receiving two or more nonopioid analgesics. Nonopioid analgesia showed the highest rates of improvement from retrospective to prospective: preoperative use of analgesics increased from 5.3% to 41.2% (P < 0.0001), postoperative use of acetaminophen increased by 27.4% (P = 0.5), Toradol by 45.5% (P = 0.11), and gabapentin by 86.7% (P < 0.0001). Postoperative nausea/vomiting prophylaxis with >1 class of antiemetic increased from 8% to 47.1% (P < 0.001). The length of stay was unchanged (5.7 versus 4.4 d, P = 0.14). CONCLUSIONS: For the successful implementation of an ERAS protocol, perceptions versus reality must be assessed to determine current practices and identify barriers to implementation.

Association of Surgeon Representation on NIH Study Sections With Receipt of Funding by Surgeon-scientists.

OBJECTIVE: Our goal was to evaluate the relationship between surgeon representation on NIH study sections and success in grant funding. SUMMARY OF BACKGROUND DATA: NIH funding for surgeon-scientists is declining. Prior work has called for increased surgeon participation in the grant review process as a strategy to increase receipt of funding by surgeon-scientists. METHODS: A retrospective review of surgeon (primary department: General, Urology, Orthopedic, Ophthalmology, Otolaryngology, Neurosurgery) representation on NIH study sections and receipt of funding was performed using NIH Research Portfolio Online Reporting Tools Expenditures and Results (RePORTER) and 2019 Blue Ridge Institute for Medical Research data. NIH chartered study section panels and ad hoc reviewers for each 2019 review date were also obtained. RESULTS: In 2019, 9239 individuals reviewed in at least 1 of the 168 study sections [190 (2.1%) surgeons, 64 (0.7%) standing members, 126 (1.4%) ad-hoc]. Most surgeons on study sections were male (65%) professors (63%). Surgeons most commonly served on bioengineering, technology, and surgical sciences (29.6% surgeons), diseases and pathophysiology of the visual system (28.3%), and surgery, anesthesiology and trauma (21%). In 2019, 773 surgeons received 1235 NIH grants (>$580 M) out of a total of 55,012 awards (2.2%). Funded surgeons were predominantly male (79%), White (68%), non-Hispanic (97%), full professors (50%), and 43% had additional advanced degrees (MPH/PhD/MBA). surgery, anesthesiology and trauma, diseases and pathophysiology of the visual system, and bioengineering, technology, and surgical sciences were the most common study sections that reviewed funded grants to surgeon-scientists. Ninety-two surgeons both received grant funding and served on study section. Study sections with higher surgeon representation were more likely to fund surgeon-scientists (P < 0.001). CONCLUSIONS: Surgeon representation on NIH study sections is strongly associated with receipt of funding by surgeon-scientists. Increasing NIH study section representation by surgeons may help to preserve the surgeon-scientist phenotype.

Sensitivity of Ribosomal RNA Character Sampling in the Phylogeny of Rhabditida.

Near-full-length 18S and 28S rRNA gene sequences were obtained for 33 nematode species. Datasets were constructed based on secondary structure and progressive multiple alignments, and clades were compared for phylogenies inferred by Bayesian and maximum likelihood methods. Clade comparisons were also made following removal of ambiguously aligned sites as determined using the program ProAlign. Different alignments of these data produced tree topologies that differed, sometimes markedly, when analyzed by the same inference method. With one exception, the same alignment produced an identical tree topology when analyzed by different methods. Removal of ambiguously aligned sites altered the tree topology and also reduced resolution. Nematode clades were sensitive to differences in multiple alignments, and more than doubling the amount of sequence data by addition of 28S rRNA did not fully mitigate this result. Although some individual clades showed substantially higher support when 28S data were combined with 18S data, the combined analysis yielded no statistically significant increases in the number of clades receiving higher support when compared to the 18S data alone. Secondary structure alignment increased accuracy in positional homology assignment and, when used in combination with paired-site substitution models, these structural hypotheses of characters and improved models of character state change yielded high levels of phylogenetic resolution. Phylogenetic results included strong support for inclusion of Daubaylia potomaca within Cephalobidae, whereas the position of Fescia grossa within Tylenchina varied depending on the alignment, and the relationships among Rhabditidae, Diplogastridae, and Bunonematidae were not resolved.

Can nematode infection cause internal bleeding in dogs? A case of Dirofilaria immitis infection in cavitary fluids.

A 9-year-old dog was presented with weight loss, respiratory effort, and an enlarged abdomen. Imaging studies and exploratory surgery showed pulmonary and splenic masses and bi-cavitary effusion, later classified as hemorrhage. Cytology of the peritoneal and pleural fluids also revealed several microfilariae. Immunologic and molecular analyses confirmed Dirofilaria immitis infection and histopathology of the spleen indicated a cavernous endothelial proliferation with undefined etiology (hemangiosarcoma vs reaction to parasite infestation). The nematode larvae are speculated to have entered body cavities via erratic migration or via hemorrhage and visceral lesions to be related to parasitism. Nematode infection should be considered as a differential diagnosis for internal bleeding of undetermined origin.

High prevalence and diversity of Toxoplasma gondii DNA in feral cat feces from coastal California.

Toxoplasma gondii is a zoonotic parasite that can cause severe morbidity and mortality in warm-blooded animals, including marine mammals such as sea otters. Free-ranging cats can shed environmentally resistant T. gondii oocysts in their feces, which are transported through rain-driven runoff from land to sea. Despite their large population sizes and ability to contribute to environmental oocyst contamination, there are limited studies on T. gondii oocyst shedding by free-ranging cats. We aimed to determine the frequency and genotypes of T. gondii oocysts shed by free-ranging domestic cats in central coastal California and evaluate whether genotypes present in feces are similar to those identified in sea otters that died from fatal toxoplasmosis. We utilized a longitudinal field study of four free-ranging cat colonies to assess oocyst shedding prevalence using microscopy and molecular testing with polymerase chain reaction (PCR). T. gondii DNA was confirmed with primers targeting the ITS1 locus and positive samples were genotyped at the B1 locus. While oocysts were not visualized using microscopy (0/404), we detected T. gondii DNA in 25.9% (94/362) of fecal samples. We genotyped 27 samples at the B1 locus and characterized 13 of these samples at one to three additional loci using multi locus sequence typing (MLST). Parasite DNA detection was significantly higher during the wet season (16.3%, 59/362) compared to the dry season (9.7%; 35/362), suggesting seasonal variation in T. gondii DNA presence in feces. High diversity of T. gondii strains was characterized at the B1 locus, including non-archetypal strains previously associated with sea otter mortalities. Free-ranging cats may thus play an important role in the transmission of virulent T. gondii genotypes that cause morbidity and mortality in marine wildlife. Management of free-ranging cat colonies could reduce environmental contamination with oocysts and subsequent T. gondii infection in endangered marine mammals and people.

Survey of large protein complexes in D. vulgaris reveals great structural diversity.

An unbiased survey has been made of the stable, most abundant multi-protein complexes in Desulfovibrio vulgaris Hildenborough (DvH) that are larger than Mr approximately 400 k. The quaternary structures for 8 of the 16 complexes purified during this work were determined by single-particle reconstruction of negatively stained specimens, a success rate approximately 10 times greater than that of previous "proteomic" screens. In addition, the subunit compositions and stoichiometries of the remaining complexes were determined by biochemical methods. Our data show that the structures of only two of these large complexes, out of the 13 in this set that have recognizable functions, can be modeled with confidence based on the structures of known homologs. These results indicate that there is significantly greater variability in the way that homologous prokaryotic macromolecular complexes are assembled than has generally been appreciated. As a consequence, we suggest that relying solely on previously determined quaternary structures for homologous proteins may not be sufficient to properly understand their role in another cell of interest.

The mitogen-activated protein kinome from Anopheles gambiae: identification, phylogeny and functional characterization of the ERK, JNK and p38 MAP kinases.

BACKGROUND: Anopheles gambiae is the primary mosquito vector of human malaria parasites in sub-Saharan Africa. To date, three innate immune signaling pathways, including the nuclear factor (NF)-kappaB-dependent Toll and immune deficient (IMD) pathways and the Janus kinase/signal transducers and activators of transcription (Jak-STAT) pathway, have been extensively characterized in An. gambiae. However, in addition to NF-kappaB-dependent signaling, three mitogen-activated protein kinase (MAPK) pathways regulated by JNK, ERK and p38 MAPK are critical mediators of innate immunity in other invertebrates and in mammals. Our understanding of the roles of the MAPK signaling cascades in anopheline innate immunity is limited, so identification of the encoded complement of these proteins, their upstream activators, and phosphorylation profiles in response to relevant immune signals was warranted. RESULTS: In this study, we present the orthologs and phylogeny of 17 An. gambiae MAPKs, two of which were previously unknown and two others that were incompletely annotated. We also provide detailed temporal activation profiles for ERK, JNK, and p38 MAPK in An. gambiae cells in vitro to immune signals that are relevant to malaria parasite infection (human insulin, human transforming growth factor-beta1, hydrogen peroxide) and to bacterial lipopolysaccharide. These activation profiles and possible upstream regulatory pathways are interpreted in light of known MAPK signaling cascades. CONCLUSIONS: The establishment of a MAPK "road map" based on the most advanced mosquito genome annotation can accelerate our understanding of host-pathogen interactions and broader physiology of An. gambiae and other mosquito species. Further, future efforts to develop predictive models of anopheline cell signaling responses, based on iterative construction and refinement of data-based and literature-based knowledge of the MAP kinase cascades and other networked pathways will facilitate identification of the "master signaling regulators" in biomedically important mosquito species.

Opioid Prescribing and Use After Pediatric Umbilical Hernia Repair.

BACKGROUND: Opioid overuse is a concern in adult and pediatric populations. Physician education may improve appropriate opioid prescribing and patient instruction for use. Prescribing and use of opioids for pain control after pediatric umbilical hernia (UH) repair before and after surgeon education was evaluated. This is a substudy of a multi-institutional study assessing prescribing practice before and after surgeon education. This study further assessed patient prescription filling patterns and parent report of pain control. METHODS: A retrospective study was performed evaluating children who underwent UH 6 months before and after an educational presentation on opioid use. Prescriptions, prescription fills, patient medication use, and pain control effectiveness were assessed. Adverse events were collected. RESULTS: There were 78 subjects in the pre-education and 99 in the post-education group. Opioid prescribed changed from 98.7% to 61.6% (P < .0001), and nonopioid prescriptions increased following education (P = .0063). The number of opioid prescriptions filled decreased (P = .0296). There were limited data on opioid doses used and quality of pain control, but the post-education group showed good pain control. There was no difference in adverse events. DISCUSSION: Surgeon education on the current opioid epidemic and strategies for opioid stewardship improves opioid prescribing and use without adversely impacting pain control or clinical outcome.

PHYLOGEOGRAPHY OF BAYLISASCARIS PROCYONIS (RACCOON ROUNDWORM) IN NORTH AMERICA.

Sequences of the mitochondrial cytochrome c oxidase 1 (COI) gene of 115 Baylisascaris procyonis individuals from 13 U.S. states and 1 Canadian province were obtained from 44 raccoon hosts to assess genetic variation and geographic structure. The maximum genetic distance between individuals was low (1.6%), consistent with a single species. Moderate COI haplotype (h = 0.60) and nucleotide (π = 0.0053) diversity were found overall. Low haplotype diversity was found among samples east of the Mississippi River (h = 0.036), suggesting that historical growth and expansion of raccoon populations in this region could be responsible for high parasite gene flow or a selective sweep of B. procyonis mtDNA. There was low genetic structure (average Φst = 0.07) for samples east of the continental divide, but samples from Colorado showed higher diversity and differentiation from midwestern and eastern samples. There was marked genetic structure between samples from east and west of the continental divide, with no haplotypes shared between these regions. There was no significant isolation by distance among any of these geographic samples. The phylogeographic patterns for B. procyonis are similar to genetic results reported for their raccoon definitive hosts. The phylogeographic divergence of B. procyonis from east and west of the continental divide may involve vicariance resulting from Pleistocene glaciation and associated climate variation.

Retrospective study of canine endoparasites diagnosed by fecal flotation methods analyzed across veterinary parasitology diagnostic laboratories, United States, 2018.

BACKGROUND: Companion animal endoparasites play a substantial role in both veterinary medicine and public health. Updated epidemiological studies are necessary to identify trends in occurrence and distribution of these parasites, and their associated risk factors. This study aimed to assess the occurrence of canine endoparasites  retrospectively, using fecal flotation  test data available through participating academic veterinary parasitology diagnostic laboratories across the United States of America (USA). METHODS: Canine fecal flotation records from ten veterinary diagnostic laboratories located in nine states in the USA acquired from January 1, 2018, to December 31, 2018, were included. RESULTS: A total of 4692 fecal flotation test results were obtained, with a majority comprised of client-owned dogs (3262; 69.52%), followed by research dogs (375; 8.00%), and shelter dogs (122; 2.60%). Samples from 976 (20.80%) dogs were positive for at least one parasite, and co-infections of two or more parasites were found in 3.82% (179/4692) of the samples. The five most commonly detected parasites were: Giardia sp., (8.33%; 391/4692), Ancylostomatidae (5.63%; 264/4692), Cystoisospora spp. (4.35%; 204/4692), Toxocara canis (2.49%;117/4692), and Trichuris vulpis (2.43%; 114/4692). Various other internal parasites, including gastrointestinal and respiratory nematodes, cestodes, trematodes, and protozoans were detected in less than 1% of samples. CONCLUSIONS: These data illustrate the importance of parasite prevention, routine fecal screening, and treatment of pet dogs. Additionally, pet owners should be educated about general parasite prevalence, prevention, and anthelmintic treatment regimens to reduce the risks of environmental contamination and zoonotic transmission.

Opioid Prescribing and Use After Pediatric Umbilical Hernia Repair.

BACKGROUND: Opioid overuse is a concern in adult and pediatric populations. Physician education may improve appropriate opioid prescribing and patient instruction for use. Prescribing and use of opioid for pain control after pediatric umbilical hernia repair (UH) before and after surgeon education was evaluated. This is a substudy of a multi-institutional study assessing prescribing practice before and after surgeon education. This study further assessed patient prescription filling pattern and parent report of pain control. METHODS: A retrospective study was performed evaluating children who underwent UH 6 months before and after an educational presentation on opioid use. Prescriptions, prescription fills, patient medication use, and pain control effectiveness were assessed. Adverse events were collected. RESULTS: There were 78 subjects in the pre- and 99 in the posteducation group. Opioid prescribed changed from 98.7% to 61.6% (P < .0001), and nonopioid prescriptions increased following education (P = .0063). The number of opioid prescriptions filled decreased (P = .0296). There were limited data on opioid doses used and quality of pain control, but the posteducation group showed good pain control. There was no difference in adverse events. DISCUSSION: Surgeon education on current opioid epidemic and strategies for opioid stewardship improves opioid prescribing and use without adversely impacting pain control or clinical outcome.

Molecular phylogenetics and species-level systematics of Baylisascaris.

Nucleotide sequences representing nine genes and five presumptive genetic loci were used to infer phylogenetic relationships among seven Baylisascaris species, including one species with no previously available molecular data. These genes were used to test the species status of B. procyonis and B. columnaris using a coalescent approach. Phylogenetic analysis based on combined analysis of sequence data strongly supported monophyly of the genus and separated the species into two main clades. Clade 1 included B. procyonis, B. columnaris, and B. devosi, species hosted by musteloid carnivores. Clade 2 included B. transfuga and B. schroederi from ursids, B. ailuri, a species from the red panda (a musteloid), and B. tasmaniensis from a marsupial. Within clade 2, geographic isolates of B. transfuga, B. schroederi (from giant panda), and B. ailuri formed a strongly supported clade. In certain analyses (e.g., some single genes), B. tasmaniensis was sister to all other Baylisascaris species rather than sister to the species from ursids and red panda. Using one combination of priors corresponding to moderate population size and shallow genetic divergence, the multispecies coalescent analysis of B. procyonis and B. columnaris yielded moderate support (posterior probability 0.91) for these taxa as separate species. However, other prior combinations yielded weak or no support for delimiting these taxa as separate species. Similarly, tree topologies constrained to represent reciprocal monophyly of B. columnaris and B. procyonis individuals (topologies consistent with separate species) were significantly worse in some cases, but not others, depending on the dataset analyzed. An expanded analysis of SNPs and other genetic markers that were previously suggested to distinguish between individuals of B. procyonis and B. columnaris was made by characterization of additional individual nematodes. The results suggest that many of these SNPs do not represent fixed differences between nematodes derived from raccoon and skunk hosts.

Transuterine infection by Baylisascaris transfuga: Neurological migration and fatal debilitation in sibling moose calves (Alces alces gigas) from Alaska.

Larval Baylisascaris nematodes (L3), resulting from transuterine infection and neural migration, were discovered in the cerebrum of sibling moose calves (Alces alces gigas) near 1-3 days in age from Alaska. We provide the first definitive identification, linking morphology, biogeography, and molecular phylogenetics, of Baylisascaris transfuga in naturally infected ungulates. Life history and involvement of paratenic hosts across a broader assemblage of mammals, from rodents to ungulates, in the transmission of B. transfuga remains undefined. Neural infections, debilitating young moose, may seasonally predispose calves to predation by brown bears, facilitating transmission to definitive hosts. Discovery of fatal neurological infections by L3 of B. transfuga in mammalian hosts serves to demonstrate the potential for zoonotic infection, as widely established for B. procyonis, in other regions and where raccoon definitive hosts are abundant. In zones of sympatry for multi-species assemblages of Baylisascaris across the Holarctic region presumptive identification of B. procyonis in cases of neurological larval migrans must be considered with caution. Diagnostics in neural and somatic larval migrans involving species of Baylisascaris in mammalian and other vertebrate hosts should include molecular-based and authoritative identification established in a phylogenetic context.

Similar yet different: co-analysis of the genetic diversity and structure of an invasive nematode parasite and its invasive mammalian host.

Animal parasitic nematodes can cause serious diseases and their emergence in new areas can be an issue of major concern for biodiversity conservation and human health. Their ability to adapt to new environments and hosts is likely to be affected by their degree of genetic diversity, with gene flow between distinct populations counteracting genetic drift and increasing effective population size. The raccoon roundworm (Baylisascaris procyonis), a gastrointestinal parasite of the raccoon (Procyon lotor), has increased its global geographic range after being translocated with its host. The raccoon has been introduced multiple times to Germany, but not all its populations are infected with the parasite. While fewer introduced individuals may have led to reduced diversity in the parasite, admixture between different founder populations may have counteracted genetic drift and bottlenecks. Here, we analyse the population genetic structure of the roundworm and its raccoon host at the intersection of distinct raccoon populations infected with B. procyonis. We found evidence for two parasite clusters resulting from independent introductions. Both clusters exhibited an extremely low genetic diversity, suggesting small founding populations subjected to inbreeding and genetic drift with no, or very limited, genetic influx from population admixture. Comparison of the population genetic structures of both host and parasite suggested that the parasite spread to an uninfected raccoon founder population. On the other hand, an almost perfect match between cluster boundaries also suggested that the population genetic structure of B. procyonis has remained stable since its introduction, mirroring that of its raccoon host.

Protein kinase C-dependent signaling controls the midgut epithelial barrier to malaria parasite infection in anopheline mosquitoes.

Anopheline mosquitoes are the primary vectors of parasites in the genus Plasmodium, the causative agents of malaria. Malaria parasites undergo a series of complex transformations upon ingestion by the mosquito host. During this process, the physical barrier of the midgut epithelium, along with innate immune defenses, functionally restrict parasite development. Although these defenses have been studied for some time, the regulatory factors that control them are poorly understood. The protein kinase C (PKC) gene family consists of serine/threonine kinases that serve as central signaling molecules and regulators of a broad spectrum of cellular processes including epithelial barrier function and immunity. Indeed, PKCs are highly conserved, ranging from 7 isoforms in Drosophila to 16 isoforms in mammals, yet none have been identified in mosquitoes. Despite conservation of the PKC gene family and their potential as targets for transmission-blocking strategies for malaria, no direct connections between PKCs, the mosquito immune response or epithelial barrier integrity are known. Here, we identify and characterize six PKC gene family members--PKCδ, PKCε, PKCζ, PKD, PKN, and an indeterminate conventional PKC--in Anopheles gambiae and Anopheles stephensi. Sequence and phylogenetic analyses of the anopheline PKCs support most subfamily assignments. All six PKCs are expressed in the midgut epithelia of A. gambiae and A. stephensi post-blood feeding, indicating availability for signaling in a tissue that is critical for malaria parasite development. Although inhibition of PKC enzymatic activity decreased NF-κB-regulated anti-microbial peptide expression in mosquito cells in vitro, PKC inhibition had no effect on expression of a panel of immune genes in the midgut epithelium in vivo. PKC inhibition did, however, significantly increase midgut barrier integrity and decrease development of P. falciparum oocysts in A. stephensi, suggesting that PKC-dependent signaling is a negative regulator of epithelial barrier function and a potential new target for transmission-blocking strategies.

Population and infection dynamics of Daubaylia potomaca (Nematoda: Rhabditida) in Helisoma anceps.

Daubaylia potomaca is an unusual parasite for several reasons. Specifically, it has a direct life cycle in which it uses a planorbid snail, Helisoma anceps , as the definitive host. In addition, adult females have been shown to be both the infective stage and the only stage documented to be shed from a live, infected host. Finally, adults, juveniles, and eggs have been observed in all tissues and blood spaces of the host, suggesting the parasite consumes and actively migrates through host tissue. The present study examined the population and infection dynamics of D. potomaca in Mallard Lake, a 4.9-ha public access pond in the Piedmont region of North Carolina. In particular, the study examined the role of seasonality on the prevalence and mean intensity of infection of D. potomaca in the snail host. Data collected from August 2008 to October 2009 suggest that prevalence and mean intensity were inversely related in the spring and fall. Prevalence in fall 2008 was 10.3% but increased to 47.3% in spring 2009. Conversely, intensity was high in fall 2008 at 52.4 ± 8.9 worms/infected host but dropped to 3.1 ± 0.3 worms/infected host in spring 2009. During the same time, the parasites within the snails went from highly aggregated populations in the fall to a less aggregated distribution in the spring. It is hypothesized that D. potomaca induces mortality of the snail hosts during the winter, followed by a rapid recruitment event of the nematodes by the snail population after torpor.