Remote Sensing Provides a Rapid Epidemiological Context for the Control of African Swine Fever in Germany.

Transboundary disease control, as for African swine fever (ASF), requires rapid understanding of the locally relevant potential risk factors. Here, we show how satellite remote sensing can be applied to the field of animal disease control by providing an epidemiological context for the implementation of measures against the occurrence of ASF in Germany. We find that remotely sensed observations are of the greatest value at a lower jurisdictional level, particularly in support of wild boar carcass search efforts.

Joining the club: First detection of African swine fever in wild boar in Germany.

African swine fever (ASF) has spread across many countries in Europe since the introduction into Georgia in 2007. We report here on the first cases of ASF in wild boar detected in Germany close to the border with Poland. In addition to the constant risk of ASF virus (ASFV) spread through human activities, movements of infected wild boar also represent a route of introduction. Since ASF emerged in Western Poland in November 2019, surveillance efforts, in particular examination of wild boar found dead, were intensified in the regions of Germany bordering with Poland. The first case of ASF in wild boar in Germany was therefore detected by passive surveillance and confirmed on 10 September 2020. By 24 September 2020, 32 cases were recorded. Testing of samples from tissues of carcasses in different stages of decomposition yielded cycle threshold values from 18 to 36 in the OIE-recommended PCR, which were comparable between the regional and national reference laboratory. Blood swabs yielded reliable results, indicating that the method is suitable also under outbreak conditions. Phylogenetic analysis of the ASFV whole-genome sequence generated from material of the first carcass detected in Germany, revealed that it groups with ASFV genotype II including all sequences from Eastern Europe, Asia and Belgium. However, some genetic markers including a 14 bp tandem repeat duplication in the O174L gene were confirmed that have so far been detected only in sequences from Poland (including Western Poland). Epidemiological investigations that include estimated postmortem intervals of wild boar carcasses of infected animals suggest that ASFV had been introduced into Germany in the first half of July 2020 or even earlier.

Differential innate immune responses of a living skin equivalent model colonized by Staphylococcus epidermidis or Staphylococcus aureus.

Staphylococcus epidermidis is a commensal on skin, whereas Staphylococcus aureus is a transient pathogen. The aim was to determine whether the skin's innate defence systems responded differently to these microorganisms. Differential gene expression of a human skin equivalent (SE) model was assessed by microarray technology, in response to colonization by S. epidermidis or S. aureus. Only a small number of transcripts were significantly (P<0.0001) increased (12) or decreased (35) with gene expression changes of >2-fold on SEs colonized with S. epidermidis compared with controls (no colonization). Expression of one innate defence gene, pentraxin 3 (PTX3), was upregulated, while psoriasin, S100A12, S100A15, beta defensin 4, beta defensin 3, lipocalin 2 and peptidoglycan recognition protein 2 were downregulated. In contrast, large numbers of transcripts were significantly increased (480) or decreased (397) with gene expression changes of >2-fold on SEs colonized with S. aureus compared with controls. There was upregulation in gene expression of many skin defence factors including Toll-like receptor 2, beta defensin 4, properdin, PTX3, proinflammatory cytokines tumour necrosis factor-alpha, IL-1 alpha, IL-1 beta, IL-17C, IL-20, IL-23A and chemokines IL-8, CCL4, CCL5, CCL20 and CCL27. These differences may partly explain why S. epidermidis is a normal skin resident and S. aureus is not.

Microbial colonization of an in vitro model of a tissue engineered human skin equivalent--a novel approach.

This was a preliminary investigation to define the conditions of colonization of a human skin equivalent (SE) model with cutaneous microorganisms. SEs of 24 mm diameter were constructed with a dermal matrix of fibrin containing fibroblasts and a stratified epidermis. Microbial colonization of the SEs was carried out in a dry environment, comparable to 'in vivo' skin, using a blotting technique to remove inoculation fluid. The microbial communities were sampled by scrub washing and viable cells enumerated on selective growth medium. Staphylococcus epidermidis, Propionibacterium acnes and Malassezia furfur (human skin commensals) and Staphylococcus aureus (transient pathogen) were colonized at inoculum densities of 10(2)-10(6) CFU SE(-1) on the surface of replicate SEs. Growth of all species was supported for upto 72-120 h, with recovery densities of between 10(4)-10(9) CFU SE(-1). A novel, real-time growth monitoring method was also developed, using S. aureus containing a lux cassette. Light output increased from 20 to 95 h, and colonization increased from 10(2) to 10(8) CFU SE(-1), as confirmed by conventional recovery. Thus, the SE model has potential to investigate interactions between resident and transient microbial communities with themselves and their habitat, and for testing treatments to control pathogen colonization of human skin.

The role of inflammation in the pathogenesis of acne and acne scarring.

Evidence now supports a pivotal role for cellular inflammatory events at all stages of acne lesion development, from preclinical initiation to clinical presentation of active lesions through to resolution. The emphasis has moved from acne as a primarily hyperproliferative disorder of the sebaceous follicle to that of an inflammatory skin disorder. However, although the sequence of events leading to lesion formation has become clearer, the triggers for initiation remain speculative. The development of noninvasive techniques to detect preclinical "acne-prone" follicles is essential before triggers for initiation can be defined. Finally, the differences highlighted in the inflammatory profiles of inflamed lesions from patients who scar, as compared with other nonscarring acne patients reinforces the view that acne is a disorder, which embraces a number of pathologies.

Inflammatory events are involved in acne lesion initiation.

The earliest subclinical acne "lesion" is a microcomedone, of which hyperproliferation of the follicular epithelium is a characteristic feature. Inflammatory cells have been observed at the periphery of these "lesions". This study investigated whether inflammatory events occur pre or post hyperproliferative changes. Cellular, vascular, and proliferative markers were examined by immunohistochemical techniques on biopsies of clinically normal follicles from uninvolved skin and early inflamed lesions from acne patients. Control follicles were obtained from non-acne subjects. Follicles from uninvolved skin exhibited no microcomedonal features. Proliferation in the epithelium was comparable to controls and was significantly lower than in inflamed lesions. Numbers of CD3+, CD4+ T cells were elevated in the perifollicular and papillary dermis although levels were not equivalent to those in papules. The number of macrophages was also greatly increased and similar to those in papules. There were no changes in blood vessel numbers or vascular intercellular adhesion molecule 1 expression but E-selectin expression was increased to levels found in papules and vascular adhesion molecule 1 levels were upregulated. Levels of the pro-inflammatory cytokine interleukin-1 were also upregulated perifollicularly. Moreover, aberrant integrin expression was demonstrated in the epidermis around these uninvolved follicles and inflamed lesions whereas the basement membrane was still intact. These results provide novel evidence for vascular endothelial cell activation and involvement of inflammatory responses in the very earliest stages of acne lesion development.

Activation of toll-like receptor 2 in acne triggers inflammatory cytokine responses.

One of the factors that contributes to the pathogenesis of acne is Propionibacterium acnes; yet, the molecular mechanism by which P. acnes induces inflammation is not known. Recent studies have demonstrated that microbial agents trigger cytokine responses via Toll-like receptors (TLRs). We investigated whether TLR2 mediates P. acnes-induced cytokine production in acne. Transfection of TLR2 into a nonresponsive cell line was sufficient for NF-kappa B activation in response to P. acnes. In addition, peritoneal macrophages from wild-type, TLR6 knockout, and TLR1 knockout mice, but not TLR2 knockout mice, produced IL-6 in response to P. acnes. P. acnes also induced activation of IL-12 p40 promoter activity via TLR2. Furthermore, P. acnes induced IL-12 and IL-8 protein production by primary human monocytes and this cytokine production was inhibited by anti-TLR2 blocking Ab. Finally, in acne lesions, TLR2 was expressed on the cell surface of macrophages surrounding pilosebaceous follicles. These data suggest that P. acnes triggers inflammatory cytokine responses in acne by activation of TLR2. As such, TLR2 may provide a novel target for treatment of this common skin disease.