廣州引入食蚊魚抗擊登革熱

The southern Chinese city of Guangzhou has introduced a fish that eats mosquito larvae, in an effort to control its worst-ever dengue fever outbreak, state news media have reported. Some scientists have warned that use of the nonnative mosquito fish could have unexpected consequences, while others say that mosquito fish are already found in Guangdong waters and the environmental impact might not be significant, but that the effectiveness of the fish may also be limited.

據國家媒體報道，爲了控制當地有史以來最嚴重的登革熱疫情，中國南方城市廣州引進了一種吃蚊子幼蟲的魚。一些科學家警告說，投放外來物種食蚊魚可能會產生意想不到的後果，但也有人說，廣東水域中已有食蚊魚，因此其環境影響可能不會太大，但這種魚的效果可能也很有限。

As of Monday, the number of dengue cases in Guangdong Province this year had reached 41,155, the local health authorities reported, with six deaths. The province has seen 200 to 300 new cases a day in recent days. That is lower than the more than 400 per day last week and the more than 1,000 per day the week before that, offering some hope that the outbreak is beginning to ease.

據當地衛生部門報告，截至週一，廣東省今年的登革熱發病人數已經達到41,155人，其中有六人死亡。最近幾天中，全省每天有200到300個新病例出現。這比上週每天400例的新增病例要低，也比上上週的每天1,000例低得多，爲疫情開始緩解帶來一些希望。

Guangzhou, the capital of Guangdong and China’s third-largest city, has seen the most cases, with more than 34,000 reported infections and one death, followed by the city of Foshan, with more than 3,000 cases and one death.

中國第三大城市、廣東省省會廣州市的疫情最嚴重，已有超過34,000個報告的感染病例、一人死亡，其次是佛山市，有3,000多個病例、一人死亡。

The dengue virus, which is carried by Aedes mosquitoes, can cause extreme fever, headaches, and muscle and joint pain in infected humans, though death is rare when proper treatment is provided. China has traditionally not seen large-scale outbreaks, but widespread urbanization and climate change have made warmer coastal areas increasingly hospitable to the mosquitoes that spread the virus.

登革熱病毒通過伊蚊傳播，能在被感染者身上引起高燒、頭痛，以及肌肉和關節疼痛，但在有適當治療的情況下，很少有患者會死亡。中國很久以來已未曾出現過大規模的登革熱爆發，但大範圍的城市化、以及氣候變化讓較溫暖的沿海地區越來越有利於傳播病毒的蚊子生存。

Officials, blaming the outbreak this year on inadequate mosquito control efforts, have increased the application of pesticides in Guangzhou in an effort to reduce the insect population. The city’s water bureau also announced on Oct. 15 that it had introduced mosquito fish from North America to “controllable static waters,” Xinhua, the state-run news agency, reported.

官員把今年的疫情暴發歸咎於控蚊工作做得不好，並已在廣州增加了殺蟲劑的使用，試圖減少蚊子的數量。據國家通訊社新華社報道，廣州水務局還在10月15日宣佈，從北美引進了食蚊魚以“控制靜態水體”。

That move prompted criticism from some experts who suggested it could upset the ecological balance in Guangdong waterways.

此舉遭到一些專家的批評，他們認爲這個做法可能會破環廣東水域的生態平衡。

“The best solution to the dengue problem is to improve the overall environment,” Li Yanliang, chairman of the National Aquatic Wildlife Conservation Association, told Xinhua. “Introducing foreign species must be meticulous. The impacts must be controlled.”

全國水生野生動物保護分會會長李彥亮對新華社說，“登革熱的防治最好的辦法是提高整體的環境，對外來物種的引進要慎重，嚴格控制外來物種帶來的負面影響。”

Liu Hansheng, an official with the Administration of Oceans and Fisheries, told Guangzhou Daily that the fish were invasive and that their introduction should be carefully controlled.

廣州市海洋與漁業自然保護區管理站救護部部長劉漢生對《廣州日報》說，食蚊魚是外來入侵物種，其投放應受到嚴格控制。

“Previously the nation brought them in to help control mosquitoes, but afterward they spread,” Mr. Liu told the newspaper. “Whether or not this leads to a disaster, the city of Guangzhou at present doesn’t have enough data to say.”

劉漢生對該報說，“此前國家是將其作爲滅蚊的幫手引進中國的，但是後來就氾濫了，至於是否成災，廣州市暫時沒有調查數據可以支撐。”

Guangzhou Daily reported that the small, finger-length fish were first brought to China in 1924 and introduced to West Lake in Hangzhou. The fish then spread to other bodies of water, and since 2006 they have been introduced to parks in Guangzhou to control mosquitoes.

《廣州日報》報道說，中國在1924年首次引進這種手指長短的小魚，投放在杭州的西湖。這種魚後來擴散到其它水體，自2006年起，這種魚被引進廣州的公園，以控制蚊子。

“Mosquito fishes are already widespread all over southern Guangdong, and I would doubt very much that adding any more would have much effect — either on the mosquitoes or on the ecology of the receiving waters,” David Dudgeon, a professor of ecology and biodiversity at the University of Hong Kong, wrote in an email.

“食蚊魚在廣東南部已很普遍，因此我不覺得，引進更多魚會產生多大影響，無論是對蚊子，還是對接納水體的生態環境，”香港大學生態學及生物多樣性教授杜德俊(David Dudgeon)在電子郵件中寫道。

Scientific opinion on the effectiveness of the mosquito fish is divided, Dr. Dudgeon said. While the fish do eat mosquitoes, the insects are not the fish’s preferred food. And the mosquito fish can have a harmful effect by eating the eggs and larvae of other native species. If mosquitoes are breeding in flower pots, puddles and other small bodies of water where the fish aren’t introduced, then their effect will be further limited.

杜德俊說，科學家對食蚊魚的有效性存在意見分歧。雖然這種魚的確吃蚊子，但蚊子不是其首選食品。而食蚊魚也吃其他本地物種的卵和幼蟲，因此可能產生有害影響。如果蚊子在花盆、水坑和其他小水體中繁殖，而不把魚引進這些水體的話，其作用將進一步受到限制。