Dyed sterile fly pupae are used to combat the spread of New World screwworm at the Chaparrosa Ranch in La Pryor, Texas. (Eric Vrin/Bloomberg)
key takeaways:
- Four New World screwworm cases were confirmed at a property in Terrell County, Texas, the largest U.S. cluster reported since investigations began this month.
- The total number of cases in the US has reached 20, threatening Texas cattle as the national herd is already depleted, although officials say food security is unaffected.
- Parts of more than a dozen Texas counties are currently under quarantine as epidemiological investigations and tracebacks are ongoing, officials said.
Four cases of New World screwworm have been confirmed on the same property in Texas, marking the largest cluster to be reported since the parasite was found in the US earlier this month.
According to the US Department of Agriculture, screwworms were found in three cattle and one goat in Terrell County, adjacent to Mexico. The Texas Animal Health Commission said in an email June 24 that all were from the same complex.
Another bovine case was reported in Medina County late June 24, according to the USDA. That brings the total number of cases in the U.S. to 20 since early June, when the screwworm was originally found in a calf in Zavala County, Texas. The outbreak is the first in the US in a decade and the first in livestock in nearly 50 years, threatening the nation’s largest cattle state at a time when the nation’s livestock is already depleted.
Screwworm is a fly whose larvae burrow into the wounds of warm-blooded animals, and it is usually spread by the movement of infected animals. The infection is treatable but can lead to death if not detected. Screwworms pose no threat to the safety of the US food supply.
The commission said the epidemiological investigation on the Terrell County cases is not yet complete, but traceback is underway to determine how the infections occurred. Parts of more than a dozen Texas counties are currently under quarantine, according to the commission.
