Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, University of Georgia, Athens, GA, 30602, USA.
Pennsylvania Game Commission, Harrisburg, PA, 17110, USA.
Parasitol Res. 2019 Oct;118(10):2767-2772. doi: 10.1007/s00436-019-06387-7. Epub 2019 Aug 6.
For two decades, the incidence and range of sarcoptic mange in black bears (Ursus americanus) in Pennsylvania has increased. The causative agent, Sarcoptes scabiei, can be directly or indirectly transmitted; therefore, data on environmental persistence is important for guiding management and public communications. The objective of this study was to determine the survival of S. scabiei at different temperatures. Full section skin samples and superficial skin scrapes were collected from bears immediately after euthanasia due to severe mange. After ~ 24 h on ice packs (shipment to lab), samples were placed in dishes at 0, 4, 18, or 30 °C and 60, 20, 12, and 25% relative humidity, respectively, and the percentage of mites alive, by life stage, was periodically determined. Humidity was recorded but not controlled. Temperature significantly affected mite survival, which was shortest at 0 °C (mostly ≤ 4 h) and longest at 4 °C (up to 13 days). No mites survived beyond 8 days at 18 °C or 6 days at 30 °C. Mites from full-thickness skin sections survived significantly longer than those from superficial skin scrapes. Adults typically survived longer than nymphs and larvae except at 30 °C where adults survived the shortest time. These data indicate that at cooler temperatures, S. scabiei can survive for days to over a week in the environment, especially if on host skin. However, these data also indicate that the environment is unlikely to be a long-term source of S. scabiei infection to bears, other wildlife, or domestic animals.
二十年来，宾夕法尼亚州黑熊（Ursus americanus）中疥螨病的发病率和范围一直在增加。致病因子疥螨（Sarcoptes scabiei）可以直接或间接传播；因此，有关环境持久性的数据对于指导管理和公众沟通非常重要。本研究的目的是确定不同温度下疥螨的生存能力。从因严重疥螨病而被安乐死的熊身上立即采集完整皮肤切片和浅层皮肤刮片。在冰袋上放置约 24 小时（运往实验室）后，将样品分别放置在 0、4、18 或 30°C 以及 60、20、12 和 25%相对湿度的培养皿中，并定期确定按生活阶段存活的螨虫百分比。记录湿度但不控制湿度。温度显著影响螨虫的存活能力，在 0°C 时最短（大多≤4 小时），在 4°C 时最长（长达 13 天）。在 18°C 或 30°C 下，没有螨虫能存活超过 8 天或 6 天。来自全厚皮肤切片的螨虫比来自浅层皮肤刮片的螨虫存活时间显著更长。成年螨虫通常比若虫和幼虫存活时间更长，除了在 30°C 下，成年螨虫存活时间最短。这些数据表明，在较冷的温度下，疥螨在环境中可以存活数天到一周以上，尤其是如果在宿主皮肤上。然而，这些数据也表明，环境不太可能成为疥螨感染熊、其他野生动物或家畜的长期来源。
