In southern Mexico, the New World screwworm fly (Cochliomyia hominivorax) has caused a real veterinary emergency. The parasite fly invasion causes severe damage to livestock: the larvae of adult flies develop in the wounds of live cattle, sheep, and other mammals, and can cause serious, potentially fatal infections within a few weeks. The U.S. agricultural authorities have suspended the import of Mexican cattle, horses, and bison for an indefinite period to contain the epidemic. This strict measure also indicates the serious threat posed by the screwworm fly. As a result, trade tensions have emerged between the USA and Mexico, as the import stop affects the cattle sectors of both countries. The New World screwworm fly is a parasite from the blowfly family (Calliphoridae) that attacks warm-blooded host animals in a particularly destructive manner. Female flies lay their eggs in open wounds. The hatching larvae literally burrow into the flesh of the attacked animal and begin to ...