By Cassandra Garrison
MEXICO CITY, Oct. 6 (Reuters) – Mexico’s agriculture ministry said on Monday another case of the flesh-eating screwworm parasite was detected in Nuevo Leon, which borders the United States, marking the state’s second confirmed case in about two weeks.
The infested calf had originated from the south of Mexico and was intercepted in the town of Montemorelos, south of Monterrey. None of the other 84 animals in the same shipment were found to be infested, the ministry said in a statement.
The New World screwworm larvae, which infest and can kill livestock if untreated, in the detected case were all found dead or dying as a result of mandatory treatments, including the antiparasitic ivermectin, the statement added.
Mexico’s agriculture ministry and sanitation agency Senasica recently told sector groups that ivermectin must be given 72 hours in advance of the movement of cattle under the supervision of staff from the International Regional Organization for Animal and Plant Health.
The screwworm outbreak has rattled the livestock sector and prompted the U.S. government to keep its border mostly closed to Mexican cattle imports since May.
“The condition in which the larvae arrived makes them unviable for reproduction, demonstrating the effectiveness of the inspection protocols at origin and destination applied to mitigate the risk of screwworm spreading,” the ministry said about the Montemorelos case.
The newly detected case was not related to a case of screwworm confirmed in Nuevo Leon state in September, the government said.
U.S. Agriculture Secretary Brooke Rollins said on X the case was believed to be an isolated incident, about 100 miles (160 km) further south than the previous case in Nuevo Leon.
“We will have boots on the ground within hours to independently verify the situation,” her post said.
Rollins has been critical of the Mexican government’s response to the outbreak, saying it had failed to curb cattle movements and tend to fly traps that monitor the wild population.
Mexico recorded 6,703 cases of animals infested with screwworm as of September 13 since the start of the outbreak in November of last year. That was compared to 5,086 confirmed cases during the previous period, which ended August 17.
(Reporting by Cassandra Garrison; additional reporting by Leah Douglass in Washington; Editing by Kylie Madry and Lincoln Feast.)
