臺灣臺北野外蚊蟲中犬心絲蟲之盛行率

Abstract

犬 心 絲 蟲 症 (dirofilariasis) 是 由 小 桿 目 蟠 尾 絲 蟲 科 (Rhabditida: Onchocercidae) 的犬心絲蟲 (Dirofilaria immitis) 感染寄生所引起，屬於一種蚊媒性人畜共通傳染病。主要宿主為犬隻，成蟲棲息於犬隻的右心室和肺動脈，臨床症狀包括咳嗽、呼吸困難，甚至死亡。犬心絲蟲也可以感染貓、狼、郊狼和其他哺乳動物。本研究的主要目標在持續監測 2023 年 6 月至 2025 年 5 月臺北地區蚊子感染犬心絲蟲的情形。本研究於臺北市內湖區與木柵區使用以乾冰為誘餌的 CDC 捕蚊燈採集蚊子，每兩週採集一個晚上。蚊子鑒定和分池 (pool) 之後，以巢式聚合酶連鎖反應 (nested PCR) 分析可能參與犬心絲蟲傳播的蚊子種類及其族群動態。本研究共收集 1926 隻，417 池，包含 9 屬 31 種蚊子。以 nested PCR 檢測犬心絲蟲感染，得到 78 池陽性，共計 15 種蚊子感染犬心絲蟲，兩年均有感染。在 Culex quinquefasciatus、 Aedes albopictus 和 Cx. pipiens molestus 物種中發現的陽性池數量最多。臺北市蚊子感染率的偏差校正最大似然估計值 (bias-corrected MLE) 為 7.6% (95% 信賴區間: 6.2% - 9.1%)。此外，本研究也首次發現 Culex 屬、 Ｍansonia 屬、 Uranotaenia 屬共 9 種蚊蟲可以被犬心絲蟲感染。本研究所建立之犬心絲蟲病媒蚊族群動態資料將有助於了解犬心絲蟲在臺北地區流行之情形及與病媒蚊之間的交互作用，可提供病媒防治、獸醫及公共衛生領域防疫政策之重要資訊。

Canine heartworm, Dirofilaria immitis (Rhabditida: Onchocercidae), is a mosquito-borne parasitic nematode that resides in the right ventricle and pulmonary arteries of infected dogs, leading to canine dirofilariasis. Clinical signs of D. immitis infection include cough, difficulty breathing, and potentially death. Although dogs are the primary hosts, D. immitis can infect cats, wolves, coyotes, and other mammals. To investigate potential mosquito vectors of D. immitis in Taipei, Taiwan, adult mosquitoes were collected from June 2023 to May 2025 using CDC light traps baited with dry ice. Detection of D. immitis in mosquito samples was performed using nested PCR. A total of 1926 mosquitoes, grouped into 417 pools representing 31 species from 9 genera, were collected. Among these, 78 pools tested positive for D. immitis. Infections were identified in 15 mosquito species and occurred throughout two years. The highest number of positive pools were found in species Culex quinquefasciatus, Aedes albopictus, and Cx. pipiens molestus. The bias-corrected maximum likelihood estimation (bias-corrected MLE) of the mosquito infection rate in Taipei was 7.6% (95% confidence interval: 6.2–9.1%). Notably, this study is the first to report natural D. immitis infections in 9 mosquito species belonging to the genera Culex, Mansonia, and Uranotaenia. The infection prevalence data presented in this study provide valuable insights into the transmission patterns of D. immitis in Taipei and its interactions with diverse mosquito species. These findings provide critical information to enhance vector control strategies and support the development of disease prevention policies in both veterinary and public health contexts.