Scabies outbreaks can be disruptive in institutional settings, and are associated with considerable but under-researched morbidity, especially in vulnerable populations. In this paper, we describe key findings from a retrospective review of scabies outbreaks reported in the literature over the past 30 years. We undertook this review to gain insights into the impact of institutional outbreaks, the burden in terms of attack rates, economic costs, treatment trends, the types of index cases and outbreak progression. We found 84 reports over 30 years, with outbreaks most frequently reported in aged care facilities (n = 40) and hospitals (n = 33). On average, scabies outbreaks persisted for 3 months, and the median attack rate was 38%. While 1% lindane was once the most commonly employed acaricide, 5% permethrin and oral ivermectin are increasingly used. Crusted scabies represented the index case for 83% of outbreaks, and scabies was misdiagnosed in 43% outbreaks. The frequency of reported scabies outbreaks has not declined consistently over time suggesting the disease is still highly problematic. We contend that more research and practice emphasis must be paid to improve diagnostic methods, surveillance and control, health staff education and management of crusted scabies to prevent the development of scabies outbreaks in institutional settings.

Scabies is an ectoparasitic infestation by the mite Sarcoptes scabiei. Although commonly self-limiting, a fraction of patients develop severely debilitating crusted scabies. The immune mechanisms underlying the development of crusted scabies are unclear, and undertaking longitudinal infection studies in humans is difficult. We utilized a porcine model to compare cellular immune responses in peripheral blood and skin of pigs with different clinical manifestations of scabies (n = 12), and in uninfected controls (n = 6). Although clinical symptoms were not evident until at least 4 weeks post-infestation, the numbers of peripheral IFNγ-secreting CD4(+) T cells and γδ T cells increased in infected pigs from week 1 post-infestation. γδ T cells remained increased in the blood at week 15 post-infestation. At week 15, skin cell infiltrates from pigs with crusted scabies had significantly higher CD8(+) T cell, γδ T cell and IL-17(+) cell numbers than those with ordinary scabies. Peripheral IL-17 levels were not increased, suggesting that localized skin IL-17-secreting T cells may play a critical role in the pathogenesis of crusted scabies development. Given the potential of anti-IL-17 immunotherapy demonstrated for other inflammatory skin diseases, this study may provide a novel therapeutic avenue for patients with recurrent crusted scabies.

A simple scheme is described for the classification of Miltenberger cell classes I to VI, which is consistent with the serologic definition of the determinants. The scheme is based on the reaction patterns obtained by immunoblotting the normal and abnormal sialoglycoproteins (SGPs) found in these cells with several murine monoclonal antibodies that recognize different epitopes on alpha-SGP (Glycophorin A). The abnormal alpha found in MiI and MiII cells is easily identified with these antibodies, as is the abnormal alpha-delta SGP found in MiV cells. Certain alpha-SGP antibodies recognize epitopes on the abnormal SGPs found in MiIII, MiIV, and MiVI cells, although the mode of inheritance of these abnormal SGPs suggests that they are related to delta-SGP (Glycophorin B). Antibody R18 reacts with the abnormal SGP of MiIII cells but not that of MiIV or MiVI cells, whereas antibody BRIC 119 reacts with MiIII, MiIV, and MiVI cells. None of the abnormal components in these three cell classes react with antibody R10 or with an antibody (BRIC 163) that recognizes an epitope on the cytoplasmic portion of alpha-SGP. The immunostaining of membranes from persons heterozygous for the MiVII and MiVIII classes revealed patterns identical to those of normal red cell membranes. However, antibody R18 did not react with any of the SGP components of homozygous MiVII cells.

An approach to improve the diagnosis of Strongyloides stercoralis infection is the use of serologic assays utilising the NIE antigen from S. stercoralis, with good diagnostic sensitivity and excellent specificity reported. Detection of antibody eluted from dried blood spots (DBS) has shown utility in large-scale seroepidemiological studies for a range of conditions and is appealing for use with children where sample collection is difficult. We adapted an existing NIE-enzyme linked immunosorbent assay (ELISA) for the testing of strongyloides antibody response on DBS, and evaluated it in a population screening and mass drug administration programme (MDA) for strongyloidiasis conducted in an Australian indigenous community. Study participants were treated with 200 μg/kg ivermectin (>15 kg) or 3× 400 mg albendazole (<15 kg). The sensitivity of the NIE DBS-ELISA was determined by receiver operator characteristic (ROC) analysis to be 85.7%. A total of 214 DBS were collected from 184 participants across two screening and MDA encounters. A total of 27 of 164 participants (16.5%) tested positive for S. stercoralis NIE-DBS prior to MDA treatment, and 6 of 50 participants (12.0%) tested positive after treatment. These prevalence values are similar to those documented by standard serology in the same community. For 30 participants where a DBS was collected at both MDA 1 and 2, a significant decline in ELISA values was evident post treatment (0.12–0.02, p = 0.0012). These results are in agreement with previous studies documenting the high seroprevalence of S. stercoralis in remote Australian Indigenous communities, and suggest that collection of dried blood spots may be a useful approach for field diagnosis of S. stercoralis seroprevalence.

Mozambique tilapia have been shown to be incredibly stress tolerant with respect to environmental salinity, hypoxia, and ammonia concentrations. Temperature challenges to this species have shown that they have difficulty with cold acclimation. The purpose of this study was to measure the effects of acclimation temperature and salinity on the thermal tolerance of Mozambique tilapia as assessed by critical thermal maxima (CT) and critical thermal minima (CT). We also monitored fish behavior and quantified ventilation rate. To our knowledge, this study was the first to investigate upper and lower thermal tolerances, and the effect of environmental salinity in this physiologically impressive species. Using predictive regression analyses of the thermal limits, thermal tolerance polygons were constructed and total areas were calculated 678.9°C for freshwater (FW)-acclimated tilapia, and 739.4°C seawater (SW)-acclimated tilapia. During the thermal challenges, we observed two novel behaviors in response to thermal challenge, ventilation cessation behavior (VCB) and aquatic surface respiration (ASR), and we conclude that the use of these behaviors extended the thermal limits of these fish in both FW and two-thirds SW by limiting the exposure of the gill epithelium to the changing environment.

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