Non-Invasive Molecular Survey of Sarcoptic Mange in Wildlife: Diagnostic Performance in Wolf Faecal Samples Evaluated by Multi-Event Capture-Recapture Models

Serological and molecular survey of canine distemper virus in red foxes (Vulpes vulpes): Exploring cut-off values and the use of protein A in ELISA tests

The wide distribution and ecological plasticity of the red fox (Vulpes vulpes) make it a potential reservoir for many infectious diseases shared with domestic and wild carnivores. One of such diseases is canine distemper, which is caused by an RNA virus and its main domestic reservoir is the dog. However, other carnivores can also participate in its maintenance, as shown by the recent upsurge of reported cases in wildlife in many parts of the world, and by the fact that red foxes may act as true reservoirs for canine distemper virus (CDV). The lack of validated serological tests for wildlife or other non-target species may be a handicap for monitoring this virus. In this study, serological assays were compared in 147 red fox sera using a commercial ELISA validated for its use in dogs and a non-specific modified ELISA with Protein A peroxidase conjugate to detect bound antibodies. In addition, the presence of CDV RNA in brain, spleen, lung, and liver samples from 144 foxes was investigated by a RT-qPCR. Through the comparison of the results of both ELISAs and the use of a finite mixture model of the optical density values obtained by both techniques, we adjusted the cut-off point of the commercial ELISA to obtain the seroprevalence in foxes. The overall seroprevalence detected was 53.7% (79/147) and 57.1% (84/147) by the commercial and modified ELISA, respectively, with a moderate agreement according to Cohen's Kappa statistic (κ = 0.491, z = 5.97, p < 0.0001). CDV RNA was detected in 30 out of 144 foxes, which resulted in 20.8% of CDV-infected foxes. At individual level, the results obtained by relating the serological status and the presence/absence of RNA in different organs were explained in terms of the pathogenesis of the infection. Our results highlight the convenience of adjusting the cut-off point when using an ELISA assay developed in domestic dogs for its use in foxes. Moreover, Protein A is confirmed to be a good alternative to be used in red foxes, presenting a good reactivity towards its IgG.

Photodynamic Therapy-Current Limitations and Novel Approaches

Photodynamic therapy (PDT) mostly relies on the generation of singlet oxygen, via the excitation of a photosensitizer, so that target tumor cells can be destroyed. PDT can be applied in the settings of several malignant diseases. In fact, the earliest preclinical applications date back to 1900’s. Dougherty reported the treatment of skin tumors by PDT in 1978. Several further studies around 1980 demonstrated the effectiveness of PDT. Thus, the technique has attracted the attention of numerous researchers since then. Hematoporphyrin derivative received the FDA approval as a clinical application of PDT in 1995. We have indeed witnessed a considerable progress in the field over the last century. Given the fact that PDT has a favorable adverse event profile and can enhance anti-tumor immune responses as well as demonstrating minimally invasive characteristics, it is disappointing that PDT is not broadly utilized in the clinical setting for the treatment of malignant and/or non-malignant diseases. Several issues still hinder the development of PDT, such as those related with light, tissue oxygenation and inherent properties of the photosensitizers. Various photosensitizers have been designed/synthesized in order to overcome the limitations. In this Review, we provide a general overview of the mechanisms of action in terms of PDT in cancer, including the effects on immune system and vasculature as well as mechanisms related with tumor cell destruction. We will also briefly mention the application of PDT for non-malignant diseases. The current limitations of PDT utilization in cancer will be reviewed, since identifying problems associated with design/synthesis of photosensitizers as well as application of light and tissue oxygenation might pave the way for more effective PDT approaches. Furthermore, novel promising approaches to improve outcome in PDT such as selectivity, bioengineering, subcellular/organelle targeting, etc. will also be discussed in detail, since the potential of pioneering and exceptional approaches that aim to overcome the limitations and reveal the full potential of PDT in terms of clinical translation are undoubtedly exciting. A better understanding of novel concepts in the field (e.g. enhanced, two-stage, fractional PDT) will most likely prove to be very useful for pursuing and improving effective PDT strategies.