• Enforcing Ecology: Geographies of the Cattle Fever Tick
• Caroline Tracey (bio)

In June of 2013, the United States Department of Agriculture (USDA) released an Environmental Impact Statement (EIS) proposing 70 miles of wire-knot game fencing through portions of Texas’s Maverick, Starr, Webb, and Zapata Counties. The document speaks of invasion, smuggling, surveillance, and vigilance.¹

These are familiar words for the border. “These invaders have been crossing into Texas for as long as time remembers,” wrote a local newspaper in 2015.² Yet neither the government nor the newspaper is describing immigration. The invaders that concern them are Boophilus annulatus and Boophilus microplus, ticks capable of carrying babesiosis—known colloquially as “tick fever” or “Texas fever”³—a disease that can be lethal to cattle. Boophilus ticks have been present in the Americas since 1493; Boophilus habitat historically extended across the American South up to, roughly, the Mason-Dixon line, above which there were too few frost-free days for the ticks’ survival.⁴ Southern cattle remained immune to babesiosis as long as they were constantly reinfected by ticks carrying babesiosis, meaning that the disease did not pose a problem as long as cattle markets remained regional. After the Civil War, however, as Texas stockmen wanted access to northern ranges and markets, they needed eradication so that their cattle would stop killing northern livestock en masse.⁵ With the cooperation of the USDA and state agencies, the ticks were eradicated from all of the United States but a Permanent Quarantine Zone (PQZ) through the border counties along the Rio Grande during a five-decade campaign culminating in 1943.⁶ Since then, concern about ticks had fallen silent. But the EIS renewed concern by pointing to a sudden, sharp increase in infestations beyond the PQZ from 2004 to 2011 that it deemed a “threat to the Nation’s livestock health and food supply” and attributed to an increase in animals crossing the border.⁷ See figures 1 and 2. [End Page 789]

Map showing areas quarantined on account of tick fever in 1906. Dotted lines show the northern boundary of the infected area at the beginning of tick eradication. Source: William Penn Ellenberger, 1940, Cattle-Fever Ticks and Methods of Eradication, U.S. Department of Agriculture Farmer's Bulletin No. 1057, p. 6, Washington, D.C., U.S. Department of Agriculture.

Tick quarantine line in 2011. Source: Matthew Messenger, “Cattle Fever Tick Eradication Program—Tick Control Barrier: Draft Environmental Impact Statement, June 2013,” U.S. Department of Agriculture Animal and Plant Health Inspection Service, p. 11.

[End Page 790]

The EIS’s dates oddly parallel human migrant traffic through South Texas, which increased sharply beginning in 2004 and peaked in 2012.⁸ June 2013 also coincided with U.S. congressional passage of the Border Security, Economic Opportunity and Immigration Modernization Act of 2013, which approved 350 new miles of border fencing between the U.S. and Mexico.⁹ Thus, while the tick fence will serve no function against human migrants, it appears that anxieties surrounding illegal immigration and porous national sovereignty are reflected in the management of tick fever.¹⁰

Yet as newspapers, government white papers, and even scientific articles promulgate the unified conclusion that the United States is “threatened by unregulated movements of illegal cattle and wildlife,”¹¹ a spike so dramatic in a single year—from 19 infestations in 2003 to 94 in 2004—seems improbable, especially solely as a result of animal movement. Moreover, the extent of animal crossings beyond the PQZ remains a matter of debate.¹² The spike appears to have far less to do with increased crossings than with political and ecological circumstances on the United States side, most significantly a 2004 change to Texas Animal Health Commission regulations that permits premises to be designated as “infested” when a tick is found on white-tailed deer or exotic hunting game (particularly nilgai antelope), not only cattle.¹³ These species were not considered a factor in eradication—deer were nearly extirpated in Texas at the time (their numbers climbed after screwworm eradication in 1964) and nilgai...

• 加强生态：牛瘟的地理分布
• Caroline Tracey（生物）

2013年6月，美国农业部（USDA）发布了《环境影响声明》（EIS），提议通过得克萨斯州的特立独行者，斯塔尔，韦伯和扎帕塔县的部分地区进行70英里的绳结游戏围栏。该文件谈到入侵，走私，监视和警惕。^1个

这些是边界的常用词。“只要时间记得，这些入侵者就一直进入得克萨斯州，”当地一家报纸在2015年写道^。2然而，政府和报纸都没有描述移民。入侵者是关注他们的微小牛蜱annulatus和微小牛蜱，蜱可携带巴贝斯虫病的-俗称“蜱热”或“得克萨斯热” ³ -a疾病，可能是致命的牛。小牛蜱自1493蜱已经存在于美洲; Boophilus栖息地历史上一直延伸到美国南部，直到梅森-迪克森（Mason-Dixon）线，在该线以上，无the的生存天数很少。⁴南部的牛，只要经常受到携带巴贝西虫病的tick虫的重新感染，就仍然对巴贝西虫病免疫，这意味着只要牛市场仍处于区域性，该病就不会构成问题。但是，在内战之后，得克萨斯州的饲养员们希望进入北部山脉和市场，因此他们需要铲除牲畜，以免他们的牛群大量杀害北部牲畜。⁵在美国农业部和州政府机构的合作下，整个美国的but虫都被消灭了，但在1943年结束的长达五个十年的运动中，沿着里奥格兰德州的边境县建立了永久检疫区（PQZ）^。6自那时以来，对壁虱的担忧已经变得沉默了。但是，EIS再次表示关注，指出从2004年到2011年，PQZ以外地区的疫情突然急剧增加，它认为这“威胁到该国的牲畜健康和粮食供应”，并且归因于越境动物的增加。⁷参见图1和2。[结束页789]

该图显示了在1906年由于tick热而被隔离的区域。虚线显示了在tick消除开始时感染区域的北部边界。资料来源：威廉·佩恩·埃伦贝格尔，威廉·佩恩·埃伦贝格，1940年，《牛瘟和根除方法》，美国农业部《农民公报》第1057号，第1页。6，华盛顿特区，美国农业部。

2011年壁虱检疫生产线。资料来源：马修·信使（Matthew Messenger），“牛瘟根除ick牛病计划–壁虱控制壁垒：环境影响声明草案，2013年6月”，美国农业动植物卫生检验局，p。11。

[结束页790]

EIS的日期奇怪地平行于通过南德克萨斯州的人口流动，从2004年开始急剧增加，并在2012年达到顶峰。2013年6月⁸日也恰逢美国国会通过了2013年的《边境安全，经济机会和移民现代化法案》，该法案批准了350部新美国和墨西哥之间的边界栅栏数英里。⁹因此，尽管壁虱栅栏对移民没有任何作用，但似乎在壁虱热的管理中反映了围绕非法移民和国家主权渗透的焦虑。¹⁰

然而，随着报纸，政府白皮书甚至科学文章发布了一个统一的结论，即美国“受到非法牛和野生动植物的无节制流动的威胁”，¹¹一年中如此激增，从2003年的19例激增到94例。在2004年-似乎不太可能，尤其是仅由于动物运动而已。此外，超出PQZ的动物穿越的程度仍是一个争论的问题。¹²与美国方面的政治和生态环境相比，高峰的发生似乎与越过交叉口的关系要少得多，最重要的是，2004年对德克萨斯动物健康委员会的规定进行了更改，该规则允许在发现滴答声时将场所指定为“出没”在白尾鹿或外来狩猎游戏（尤其是尼尔盖羚羊）上，不仅是牛。¹³这些物种没有被认为是根除物种-当时在得克萨斯州几乎灭绝了鹿（1964年根除screw虫之后，鹿的数量有所攀升），而尼尔盖尔...