Parasitology

Federal officials have confirmed additional New World screwworm detections in Texas and New Mexico, bringing the total to 5 cases in 6 days, including the first in a companion animal since the parasite’s return to the United States.

Christopher Lee, DVM, MPH, DACVPM, DACVM (Parasitology), on why the NWS detection in Texas signals something far bigger—and what clinicians need to do now. Plus: early warning signs, identification, lab submission, and risk to pets.

Coverage of New World screwworm detections, FDA treatment authorizations, and response efforts across animal health and agriculture as the parasite reemerges in the United States.

The affected animal is a 3-week-old calf in Zavala County, Texas. To date, APHIS has reported no further detections.

Zoetis' doramectin injection is now indicated for use in dairy cows, horses, sheep, swine, and deer to help mitigate NWS myiasis.

New research and treatment methods are finding ways to combat the parasitic Varroa mite to save colonies from collapsing.

Researchers at the University of Washington have found a dangerous tapeworm in Washington coyotes, raising potential concerns for dogs and humans.

Tick risk is no longer seasonal—Susan E. Little, DVM, PhD, DACVM (Parasitology), explains what’s changed and how to protect patients year-round.

A US Environmental Protection Agency emergency exemption is allowing US officials to import Tanidil as part of a growing federal response to prevent New World screwworm from entering the country.

The authorization adds to a growing list of treatments cleared under emergency use as federal agencies ramp up efforts to prevent New World screwworm from reestablishing in the United States.

A study from The Ohio State University provides the first quantitative evidence that 2 tick species can survive for weeks on common household flooring, underscoring the need for veterinarians to reinforce year-round tick prevention and home risk mitigation strategies with clients.

The FDA emergency use authorization (EUA) expands the New World screwworm treatment tool kit to cattle, small ruminants, horses, exotic mammals, and wild and pet birds.

The construction of a sterile fly production facility is underway at Moore Air Base in Edinburg, Texas, to help combat New World screwworm (NWS).

Susan E. Little, DVM, PhD, DACVM (Parasitology), explains why tapeworm and heartworm tests miss cases, how fecal flotation falls short, and why clinician judgment matters most.

Long-duration flea and tick collars can be a valuable, practical component of comprehensive parasite prevention.

The American Heartworm Society has released the results of its latest survey mapping where the parasite's presence is growing, declining, or staying the same.

Global veterinary leaders unite in a Prevention Pledge urging year-round parasite control as fleas, ticks, and worms spread, raising emerging disease risks for pets and people.

Global survey finds many pets get parasites, yet owners want clearer prevention advice; vets urge year‑round flea, tick and heartworm protection.

Fluralaner for extended-release injectable suspension (Bravecto Quantum; Merck Animal Health) is indicated for treating flea and tick infestations in dogs.

The FDA has indexed Faunamor, an antiparasitic and antimicrobial treatment for white spot disease (Ichthyophthirius multifiliis) in ornamental finfish, making the drug legally available in the United States.

Once eradicated from the US in the 1960s, New World screwworm is again driving prevention efforts as cases move closer to the US-Mexico border.

In September 2025, the FDA issued a conditional approval for another drug indicated to prevent and treat New World screwworm (NWS) larval infestations in cattle.

Although the parasite has not yet been detected in the US, officials warn that its northward movement poses a serious risk to livestock and wildlife.

A new study from Australia reveals the complex evolutionary history of canine heartworms, challenging previous beliefs about their global spread and origins.