The United States Department of Agriculture has confirmed a second instance of New World screwworm infestation in Texas, prompting state-level emergency measures and the imposition of livestock import bans by Canada.

美國農業部已確認德州出現第二起新世界螺旋蠅感染個案，促使州政府採取緊急措施，且加拿大已實施牲畜進口禁令。

The New World screwworm (Cochliomyia hominivorax) is a parasitic dipteran whose larvae consume the viable tissue of warm-blooded hosts, potentially resulting in fatality if clinical intervention is absent. The current crisis commenced with the detection of a three-week-old calf with an umbilical lesion in La Pryor, Texas. Subsequently, a second case was identified in a one-month-old calf in Zavala County, situated approximately 5.6 miles from the primary site. These detections represent the first occurrences of the parasite in the United States since the 1960s, following a northward progression from Central America and Mexico observed in 2023.

新世界螺旋蠅 (Cochliomyia hominivorax) 是一種寄生雙翅目昆蟲，其幼蟲會消耗溫血宿主的活組織，若缺乏臨床干預，可能會導致死亡。目前的危機始於在德州 La Pryor 發現一頭三週大、臍部有病變的小牛。隨後，在距離主場地約 5.6 英里的 Zavala 郡又發現了第二起個案，為一頭一個月大的小牛。這些發現代表了該寄生蟲自 1960 年代以來首次在美國出現，此前在 2023 年觀察到其從中美洲和墨西哥向北推進。

In response to these findings, the USDA's Animal and Plant Health Inspection Service (APHIS) and the Texas Animal Health Commission (TAHC) have implemented a quarantine zone characterized by stringent movement controls and enhanced surveillance. Governor Greg Abbott has issued a statewide disaster declaration to facilitate the reallocation of government resources. A primary component of the mitigation strategy involves the deployment of millions of sterile male flies to disrupt the reproductive cycle of the wild population, supplemented by the construction of specialized sterile fly facilities and the utilization of detection canines.

為了回應這些發現，美國農業部的動植物衛生檢驗局 (APHIS) 與德州動物健康委員會 (TAHC) 已實施隔離區，其特點是嚴格的移動管制與加強監測。州長 Greg Abbott 已發布全州災難宣言，以利於政府資源的重新分配。緩解策略的主要組成部分包括投放數百萬隻不孕雄飛，以破壞野生族群的繁殖週期，並輔以建設專業的不孕飛設施及利用偵測犬。

The economic implications are substantial, as Texas is the preeminent cattle-producing state in the U.S. The potential for a widespread outbreak threatens to diminish cattle supplies and increase production costs. Furthermore, the northward migration of the parasite has already contributed to a contraction in the U.S. beef industry due to the closure of the U.S.-Mexico border to live cattle imports. Internationally, the Canadian Food Inspection Agency (CIFA) has enacted a temporary prohibition on the entry of livestock, including horses, that were present in Texas within 21 days of arrival. While CIFA noted that Canada's temperate climate is generally inhospitable to the long-term establishment of the fly, the measure is characterized as a necessary risk mitigation protocol.

經濟影響十分重大，因為德州是美國首屈一指的牛隻生產州。大規模爆發的可能性威脅到牛隻供應的減少並增加生產成本。此外，該寄生蟲的北移已導致美國牛肉業萎縮，因為美墨邊境已禁止進口活牛。在國際方面，加拿大食品檢驗局 (CIFA) 已對抵達前 21 天內曾於德州停留的牲畜（包括馬匹）實施臨時禁入令。儘管 CIFA 指出加拿大的溫帶氣候通常不利於該蠅類的長期建立，但此措施被定性為必要的風險緩解協定。

Current efforts are focused on the containment of the parasite within the established quarantine zones through biological control and rigorous veterinary surveillance.

目前的努力集中於透過生物控制與嚴格的獸醫監測，將寄生蟲控制在已建立的隔離區內。