#19,223
The spread of the New World Screwworm (NWS) in Texas continues to accelerate with 10 counties now reporting detections in livestock. Thus far, we've not seen any reports in wildlife, although they must certainly exist.
Currently Edwards county has reported the most detections (n=6), followed closely by Crockett County (n=5).
Given the life cycle of the NWS can be as short as 21 days (see below) we are likely already well into the second generation in Texas, which may account for the doubling of cases reported over the past 7 days.
Note: The NWS is extremely cold intolerant, and can only successfully overwinter in extreme south Texas and Southern Florida (and then, only during mild winters).
While the return of cold weather in the fall should kill off the NWS population in the United States, we could see 5 or 6 more generations emerge before then, each likely larger than the last.
At least, until the release of sterile flies begins to have an effect.
Reportedly, the USDA is able to disperse between 4 and 8 million sterile screwworm flies per week into the known infested counties of Texas.
New production facilities are being constructed, including a massive sterile fly production facility at Moore Air Base in South Texas, which is expected to produce 100 million sterile flies per week by November 2027 (increasing to 300 million a week by the end of 2028).
If we start seeing a decline in cases later in the summer, it could be an early indication the program is having an impact. Until then, Texas (and potentially other states) have a long hot battle ahead.
