New World screwworm (NWS, Cochliomyia hominivorax) is a serious pest recently detected in the Southwestern United States. It can lead to significant economic losses for livestock producers, highlighting the importance of awareness. This fact sheet answers common questions about NWS and how to protect your livestock.
What is NWS?
NWS is a parasitic fly widespread in the Caribbean and South America that mainly affects animal health. Their larvae (maggots) feed on the living tissue of warm-blooded animals by burrowing into the flesh. This infestation, called myiasis, causes painful lesions that can be lethal when left untreated.
Why is NWS a concern for livestock producers?
NWS infestations can cause severe lesions and predispose animals to secondary infections, resulting in economic losses due to reduced productivity, treatment costs, and mortality. Additionally, NWS not only affects livestock but can also affect wildlife, pets, birds, and occasionally humans.
How do animals get infested with NWS?
Female NWS flies lay eggs in wounds and sometimes in body openings such as the mouth, nose, vulva, and anus. The eggs hatch into larvae that look like screws. Animals are most at risk after routine procedures that create wounds, such as castration, dehorning, tail docking, and shearing. Other risk factors include untreated newborn navels, placenta retention, uterine prolapses, tick bites, and injuries caused by sharp objects, equipment, or fencing.
Source : psu.edu