Dirofilariasis mouse models for heartworm preclinical research.

Introduction: Dirofilariasis, including heartworm disease, is a major emergent veterinary parasitic infection and a human zoonosis. Currently, experimental infections of cats and dogs are used in veterinary heartworm preclinical drug research. Methods: As a refined alternative in vivo heartworm preventative drug screen, we assessed lymphopenic mouse strains with ablation of the interleukin-2/7 common gamma chain (γc) as susceptible to the larval development phase of Dirofilaria immitis. Results: Non-obese diabetic (NOD) severe combined immunodeficiency (SCID)γc-/- (NSG and NXG) and recombination-activating gene (RAG)2-/-γc-/- mouse strains yielded viable D. immitis larvae at 2-4 weeks post-infection, including the use of different batches of D. immitis infectious larvae, different D. immitis isolates, and at different laboratories. Mice did not display any clinical signs associated with infection for up to 4 weeks. Developing larvae were found in subcutaneous and muscle fascia tissues, which is the natural site of this stage of heartworm in dogs. Compared with in vitro-propagated larvae at day 14, in vivo-derived larvae had completed the L4 molt, were significantly larger, and contained expanded Wolbachia endobacteria titres. We established an ex vivo L4 paralytic screening system whereby assays with moxidectin or levamisole highlighted discrepancies in relative drug sensitivities in comparison with in vitro-reared L4 D. immitis. We demonstrated effective depletion of Wolbachia by 70%-90% in D. immitis L4 following 2- to 7-day oral in vivo exposures of NSG- or NXG-infected mice with doxycycline or the rapid-acting investigational drug, AWZ1066S. We validated NSG and NXG D. immitis mouse models as a filaricide screen by in vivo treatments with single injections of moxidectin, which mediated a 60%-88% reduction in L4 larvae at 14-28 days. Discussion: Future adoption of these mouse models will benefit end-user laboratories conducting research and development of novel heartworm preventatives via increased access, rapid turnaround, and reduced costs and may simultaneously decrease the need for experimental cat or dog use.

Process mining to discover patterns in patient outcomes in a Psychological Therapies Service.

In the mental health sector, Psychological Therapies face numerous challenges including ambiguities over the client and service factors that are linked to unfavourable outcomes. Better understanding of these factors can contribute to effective and efficient use of resources within the Service. In this study, process mining was applied to data from the Northern Health and Social Care Trust Psychological Therapies Service (NHSCT PTS). The aim was to explore how psychological distress severity pre-therapy and attendance factors relate to outcomes and how clinicians can use that information to improve the service. Data included therapy episodes (N = 2,933) from the NHSCT PTS for adults with a range of mental health difficulties. Data were analysed using Define-Measure-Analyse model with process mining. Results found that around 11% of clients had pre-therapy psychological distress scores below the clinical cut-off and thus these individuals were unlikely to significantly improve. Clients with fewer cancelled or missed appointments were more likely to significantly improve post-therapy. Pre-therapy psychological distress scores could be a useful factor to consider at assessment for estimating therapy duration, as those with higher scores typically require more sessions. This study concludes that process mining is useful in health services such as NHSCT PTS to provide information to inform caseload planning, service management and resource allocation, with the potential to improve client's health outcomes.

Inpatient teledermatology improves diagnostic accuracy and management of erythroderma in hospitalized patients.

With the onset of the COVID-19 pandemic, healthcare providers have made increasing use of inpatient teledermatology; however, few studies have analysed the impact of teledermatology on patient outcomes. In this study, we investigated the diagnostic concordance between the primary team and teledermatologist, and we analysed the impact of this technology on the diagnosis and management of erythroderma, a condition with high morbidity and mortality. Overall, out of 2987 inpatient teledermatology encounters reviewed, we found 33 cases of erythroderma, and, of these, 78.8% had a change in diagnosis after teledermatology consult, 81.8% were recommended biopsy and all patients had a change in topical/systemic therapy. We hope to promote further study of the efficacy of teledermatology as it may begin to address large gaps in dermatological access to care particularly in regional and community hospitals.

Meteoroid Impacts as a Source of Bennu's Particle Ejection Events.

Asteroid (101955) Bennu, a near-Earth object with a primitive carbonaceous chondrite-like composition, was observed by the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) spacecraft to undergo multiple particle ejection events near perihelion between December 2018 and February 2019. The three largest events observed during this period, which all occurred 3.5 to 6 hr after local noon, placed numerous particles <10 cm on temporary orbits around Bennu. Here we examine whether these events could have been produced by sporadic meteoroid impacts using the National Aeronautics and Space Administration's (NASA) Meteoroid Engineering Model 3.0. Most projectiles that impact Bennu come from nearly isotropic or Jupiter-family comets and have evolved toward the Sun by Poynting-Robertson drag. We find that 7,000-J impacts on Bennu occur with a biweekly cadence near perihelion, with a preference to strike in the late afternoon (~6 pm local time). This timing matches observations. Crater scaling laws also indicate that these impact energies can reproduce the sizes and masses of the largest observed particles, provided the surface has the cohesive properties of weak, porous materials. Bennu's ejection events could be caused by the same kinds of meteoroid impacts that created the Moon's asymmetric debris cloud observed by the Lunar Atmosphere and Dust Environment Explorer (LADEE). Our findings also suggest that fewer ejection events should take place as Bennu moves further away from the Sun, a result that can be tested with future observations.

Host ABC transporter proteins may influence the efficacy of ivermectin and possibly have broader implications for the development of resistance in parasitic nematodes.

ABC transporter proteins function to extrude compounds from the cell. These proteins present an obstacle for treatment and for overcoming drug resistance as they are expressed by both host and parasite, and function similarly. The contribution of host ABC proteins to drug efficacy was examined using ivermectin and a Brugia malayi model system. Parallel in vitro and in vivo experiments were conducted using equal concentrations of ivermectin. The motilities and fecundity of B. malayi exposed to ivermectin in vitro were significantly lower than those treated in vivo. The higher motilities were correlated with low concentrations of ivermectin in worms extracted from treated hosts. The expression of ABC proteins was significantly higher in worms treated in vitro compared to those treated in vivo as well as in gerbils treated with ivermectin than in non-treated controls. The results suggest that host ABC transporters may influence the efficacy of ivermectin.

Identification of Dirofilaria immitis proteins recognized by antibodies from infected dogs.

The identification of excreted-secreted (ES) proteins of filarial nematodes as potential diagnostic reagents is an important requirement for the development of methods to determine level of infection in the host, especially for human filariae. Dirofilaria immitis, the canine heartworm, is a widespread and important veterinary pathogen and is a useful model for filarial parasites of humans. An analysis of proteins released from adult D. immitis (the secretome) in culture is available. We sought to identify D. immitis ES proteins found in vivo to validate the in vitro secretome and to investigate them as potential diagnostic reagents. Cultures of D. immitis adults obtained from infected dogs were maintained for 72 hr with daily changes of media. Proteins were concentrated from spent media by standard methods and were passed through Protein-A columns containing purified IgG antibodies from heartworm-infected dogs. Following extensive washing, heartworm proteins recognized by the antibodies were eluted from these columns and submitted for analysis by tandem mass spectrometry (MS/MS). As a comparison, somatic proteins from adult D. immitis female parasites and microfilaria were also processed and analyzed by the same protocol. Six, 9, and 12 proteins were identified by MS/MS in the ES, adult female, and microfilaria samples, respectively. The identification of the most abundant parasite proteins present in the serum of infected hosts offers a rational approach to the development of new diagnostic assays that may be applicable across the Filarioidea.

Infant feeding practices in the first 24-48 h of life in healthy term infants.

AIM: To examine in-hospital infant feeding practices, focusing on initiation and prevalence of breastmilk expression and to describe the proportion of women having a breast pump immediately after birth. METHODS: Postpartum women were recruited from three hospitals in Melbourne, Australia, between 2009 and 2011. INCLUSION CRITERIA: having had a healthy singleton term infant, intending to breastfeed and fluency in English. Data were collected using a structured questionnaire. RESULTS: Just over 1000 women were recruited at 24-48 h postpartum; 50% were primiparous. Forty-seven per cent of infants had been fully breastfeeding at the breast from birth, and another 47% had received at least some expressed breastmilk. Forty per cent of first-time mothers reported having had a problem breastfeeding, and 46% already had a breast pump prior to the birth of their infant. CONCLUSIONS: Early breastfeeding problems were common, and less than half the infants had fed only at the breast in the first days of life. Given the normalization of breastmilk expression, more evidence is needed regarding the impact of expressing on duration of breastmilk feeding and maternal health outcomes.

The Rab6 effector Bicaudal D1 associates with Chlamydia trachomatis inclusions in a biovar-specific manner.

Chlamydia species are obligate intracellular bacteria that replicate within a membrane-bound vacuole, the inclusion, which is trafficked to the peri-Golgi region by processes that are dependent on early chlamydial gene expression. Although neither the host nor the chlamydial proteins that regulate the intracellular trafficking have been clearly defined, several enhanced green fluorescent protein (EGFP)-tagged Rab GTPases, including Rab6, are recruited to Chlamydia trachomatis inclusions. To further characterize the association of Rab6 with C. trachomatis inclusions, we examined the intracellular localization of guanine nucleotide-binding mutants of Rab6 and demonstrated that only active GTP-bound and not inactive GDP-bound EGFP-Rab6 mutants were recruited to the inclusion, suggesting that EGFP-Rab6 interacts with the inclusion via a host Rab6 effector or a chlamydial protein that mimics a Rab6 effector. Using EGFP-tagged fusion proteins, we also demonstrated that the Rab6 effector Bicaudal D1 (BICD1) localized to C. trachomatis inclusions in a biovar-specific manner. In addition, we demonstrated that EGFP-Rab6 and its effector EGFP-BICD1 are recruited to the inclusion in a microtubule- and Golgi apparatus-independent but chlamydial gene expression-dependent mechanism. Finally, in contrast to the Rab6-dependent Golgi apparatus localization of endogenous BICD1, EGFP-BICD1 was recruited to the inclusion by a Rab6-independent mechanism. Collectively, these data demonstrate that neither Rab6 nor BICD1 is trafficked to the inclusion via a Golgi apparatus-localized intermediate, suggesting that each protein is trafficked to the C. trachomatis serovar L2 inclusion by a unique, but as-yet-undefined, mechanism.

The GTPase Rab4 interacts with Chlamydia trachomatis inclusion membrane protein CT229.

Chlamydiae, which are obligate intracellular bacteria, replicate in a nonlysosomal vacuole, termed an inclusion. Although neither the host nor the chlamydial proteins that mediate the intracellular trafficking of the inclusion have been clearly identified, several enhanced green fluorescent protein (GFP)-tagged Rab GTPases, including Rab4A, are recruited to chlamydial inclusions. GFP-Rab4A associates with inclusions in a species-independent fashion by 2 h postinfection by mechanisms that have not yet been elucidated. To test whether chlamydial inclusion membrane proteins (Incs) recruit Rab4 to the inclusion, we screened a collection of chlamydial Incs for their ability to interact with Rab4A by using a yeast two-hybrid assay. From our analysis, we identified a specific interaction between Rab4A and Chlamydia trachomatis Inc CT229, which is expressed during the initial stages of infection. CT229 interacts with only wild-type Rab4A and the constitutively active GTPase-deficient Rab4AQ67L but not with the dominant-negative GDP-restricted Rab4AS22N mutant. To confirm the interaction between CT229 and Rab4A, we demonstrated that DsRed-CT229 colocalized with GFP-Rab4A in HeLa cells and more importantly wild-type and constitutively active GFP-Rab4A colocalized with CT229 at the inclusion membrane in C. trachomatis serovar L2-infected HeLa cells. Taken together, these data suggest that CT229 interacts with and recruits Rab4A to the inclusion membrane and therefore may play a role in regulating the intracellular trafficking or fusogenicity of the chlamydial inclusion.

Trichinellosis in the United States, 1991-1996: declining but not gone.

Since the U.S. Public Health Service began recording statistics on trichinellosis in 1947, the number of cases reported by state health departments has decreased steadily. In the late 1940s, health departments reported an average of 400 cases and 10-15 deaths each year. From 1991 to 1996, the period covered in this report, three deaths in 230 cases were reported to the Centers for Disease Control and Prevention (an average of 38 cases per year), including 14 multiple case outbreaks from 31 states and Washington, DC. Information on the suspected food item was available for 134 (58%) of the 230 reported cases. Pork was implicated in 80 (60%) cases, bear meat in 31 (23%), walrus meat in 13 (10%), and cougar meat in 10 (7%). Sausage was the most frequently implicated pork product (i.e., 57 of the 64 cases for which the form of the pork product was identified). The proportion of trichinellosis cases attributable to consumption of commercial pork continued to decrease; this decrease was probably due to a combination of factors, including the continued reduction in the prevalence of Trichinella spiralis in domestic swine, the increased use of home freezers, and the practice of thoroughly cooking pork. As a proportion of all cases reported, those associated with wild game meat products has increased; however, the absolute numbers of such cases have remained similar at approximately 9-12 per year. The continued multiple case outbreaks and the identification of nonpork sources of infection indicate the need for further education and control measures.