Dipartimento di Sanità Pubblica e Malattie Infettive, Sapienza Università di Roma, Rome, Italy.
Dipartimento di Malattie Infettive, Istituto Superiore di Sanità, Rome, Italy.
Parasit Vectors. 2024 Nov 6;17(1):455. doi: 10.1186/s13071-024-06526-9.
Five species of the Phortica genus (Diptera: Drosophilidae) are known in Europe and the Middle East. Among these, Phortica variegata and Phortica okadai are better known for their role as vectors of the zoonotic eyeworm Thelazia callipaeda. Other species, such as Phortica semivirgo and Phortica oldenbergi, have been studied less. Given the paucity of data about these Phortica spp. vectors, we explored the population dynamics and ecology of Phortica spp. in an area highly endemic for T. callipeada (Manziana, Rome, Central Italy).
Phortica spp. flies were collected over a 3-year period (2018-2020) during their active season (April-October) with a sweep net while hovering around fermenting fruits or a human operator acting as baits. Collected flies were morphologically identified and tested for a T. callipeada infection and for the presence of Wolbachia, by polymerase chain reaction (PCR). Population dynamics of species collected was associated to environmental drivers through generalized additive models.
Of the 5564 flies collected, 90.8% were P. variegata, 9.1% were P. oldenbergi, 0.05% were P. semivirgo, and one specimen was P. okadai. Only P. variegata scored molecularly infected with T. callipeada throughout the 3-year sampling period (1.8%). Phortica oldenbergi, observed consistently during the entire sampling period, exhibited a marked preference for fruit traps, contrasting with the lachryphagous activity of P. variegata. Analysis of environmental drivers of P. oldenbergi and P. variegata population dynamics indicated temperature, wind speed, and pressure as significant factors. In addition, Wolbachia pipientis endosymbiont was detected in P. oldenbergi and P. okadai.
For the first time, this study analysed several ecological aspects of Phortica species coexisting in a T. callipeada endemic area, highlighting different behaviors in the same environment and their vectorial role. Notably, this is also the first report of the presence of P. oldenbergi in Italy and P. okadai in Europe, underscoring the importance of extensive sampling for detecting potential vectors and alien species with direct implications for vector-borne disease epidemiology.
欧洲和中东已知有五种 Phortica 属（双翅目：果蝇科）。其中，Phortica variegata 和 Phortica okadai 因其作为动物眼部寄生虫 Thelazia callipaeda 的传播媒介而更为人所知。其他物种，如 Phortica semivirgo 和 Phortica oldenbergi，则研究较少。鉴于这些 Phortica spp. 媒介物的数据稀缺，我们在一个高度流行 T. callipeada 的地区（意大利罗马的 Manziana）探索了 Phortica spp. 的种群动态和生态学。
在 2018 年至 2020 年的活跃季节（4 月至 10 月），我们使用捕蝇网收集了 Phortica spp. 苍蝇，这些苍蝇在发酵水果或充当诱饵的人类操作员周围盘旋。收集的苍蝇通过聚合酶链反应（PCR）进行形态鉴定和 T. callipeada 感染以及 Wolbachia 存在的检测。通过广义加性模型将收集到的物种的种群动态与环境驱动因素联系起来。
在收集的 5564 只苍蝇中，90.8%为 P. variegata，9.1%为 P. oldenbergi，0.05%为 P. semivirgo，还有一只标本为 P. okadai。只有 P. variegata 在整个 3 年采样期间在分子上感染了 T. callipeada（1.8%）。在整个采样期间一直观察到的 Phortica oldenbergi 对水果陷阱表现出明显的偏好，与 P. variegata 的泪液摄取活动形成对比。对 Phortica oldenbergi 和 P. variegata 种群动态的环境驱动因素分析表明，温度、风速和压力是重要因素。此外，还在 P. oldenbergi 和 P. okadai 中检测到 Wolbachia pipientis 内共生体。
这是首次分析共存于 T. callipeada 流行地区的 Phortica 物种的几个生态方面，强调了在相同环境中不同行为及其媒介作用。值得注意的是，这也是首次在意大利报告 P. oldenbergi 的存在和欧洲的 P. okadai 的存在，强调了广泛采样对于检测潜在媒介物和具有直接影响虫媒传播疾病流行病学的外来物种的重要性。
