Batrachochytrium dendrobatidis in natural and farmed Louisiana crayfish populations: prevalence and implications.

The pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd) has been linked to global declines and extinctions of amphibians, making it one of the most devastating wildlife pathogens known. Understanding the factors that affect disease dynamics in this system is critical for mitigating infection and protecting threatened species. Crayfish are hosts of this pathogen and can transmit Bd to amphibians. Because they co-occur with susceptible amphibian communities, crayfish may be important alternative hosts for Bd. Understanding the prevalence and seasonal dynamics of crayfish infections is of agricultural and ecological interest in areas where crayfish are farmed and traded for human consumption. We conducted a survey of Bd in farmed and natural crayfish (Procambarus spp.) populations in Louisiana, USA. We found that Bd prevalence and infection intensity was low in both farmed and native populations and that prevalence varied seasonally in wild Louisiana crayfish. This seasonal pattern mirrors that seen in local amphibians. As crayfish are an important globally traded freshwater taxon, even with low prevalence, they could be an important vector in the spread of Bd.

Postoperative chemoradiotherapy with cisplatin is superior to radioimmunotherapy with cetuximab and radiotherapy alone : Analysis of the Austrian head and neck cancer registry of the AGMT.

BACKGROUND: The addition of cisplatin or cetuximab to radiotherapy in patients with locally advanced squamous cell carcinoma of the head and neck (SCCHN) has significantly improved the outcome. While the superiority of cisplatin over cetuximab in combination with radiotherapy has been shown in a definitive setting, we set out to compare postoperative chemoradiotherapy with cisplatin to radioimmunotherapy with cetuximab and radiotherapy alone within the Austrian head and neck cancer registry of the Working Group on Pharmaceutical Tumor Treatment (AGMT) study group. MATERIAL AND METHODS: In the AGMT head and neck cancer registry, data of 557 patients with SCCHN from five Austrian cancer centers were prospectively collected between 2012 and 2017. Of these patients 120 received postoperative chemoradiotherapy with cisplatin, 26 patients received postoperative radioimmunotherapy with cetuximab and 56 patients were treated with adjuvant radiotherapy only. Patient characteristics, stage of disease, details on treatment as well as survival were analyzed by a chart-based review. RESULTS: In patients treated with postoperative radiotherapy the addition of cisplatin significantly improved progression-free survival (PFS) and overall survival (OS) compared to cetuximab (PFS 84.2 months vs. 17.0 months, p = 0.04, OS not reached vs. 46.0 months, p = 0.02) and PFS compared to radiotherapy alone (PFS 84.2 months vs. 28.5 months, p < 0.01). Patients treated with cetuximab were significantly older and had a worse performance score than patients receiving cisplatin or radiotherapy alone. CONCLUSION: This study confirmed the importance of multimodal treatment concepts in patients with locally advanced SCCHN. Postoperative cetuximab might be an option in patients not eligible for high-dose cisplatin but cisplatin should remain the standard of care.

Dynamics of Chytridiomycosis during the Breeding Season in an Australian Alpine Amphibian.

Understanding disease dynamics during the breeding season of declining amphibian species will improve our understanding of how remnant populations persist with endemic infection, and will assist the development of management techniques to protect disease-threatened species from extinction. We monitored the endangered Litoria verreauxii alpina (alpine treefrog) during the breeding season through capture-mark-recapture (CMR) studies in which we investigated the dynamics of chytridiomycosis in relation to population size in two populations. We found that infection prevalence and intensity increased throughout the breeding season in both populations, but infection prevalence and intensity was higher (3.49 and 2.02 times higher prevalence and intensity, respectively) at the site that had a 90-fold higher population density. This suggests that Bd transmission is density-dependent. Weekly survival probability was related to disease state, with heavily infected animals having the lowest survival. There was low recovery from infection, especially when animals were heavily infected with Bd. Sympatric amphibian species are likely to be reservoir hosts for the disease and can play an important role in the disease ecology of Bd. Although we found 0% prevalence in crayfish (Cherax destructor), we found that a sympatric amphibian (Crinia signifera) maintained 100% infection prevalence at a high intensity throughout the season. Our results demonstrate the importance of including infection intensity into CMR disease analysis in order to fully understand the implications of disease on the amphibian community. We recommend a combined management approach to promote lower population densities and ensure consistent progeny survival. The most effective management strategy to safeguard the persistence of this susceptible species might be to increase habitat area while maintaining a similar sized suitable breeding zone and to increase water flow and area to reduce drought.