New data on EXZOLT® by MSD Animal Health to fight red mite


MSD Animal Health, a division of Merck & Co., Inc., Kenilworth, N.J., USA, announced new data on EXZOLT® (fluralaner), the first systemic treatment for poultry red mite infestations (Dermanyssus gallinae), presented at the 21st World Veterinary Poultry Association Congress (WVPAC 2019), September 16-20, in Bangkok, Thailand.

Conveniently administered via drinking water, EXZOLT® takes a novel approach that virtually eliminates poultry red mites in production houses of any size or type, including free-range.

“Red mite infestations significantly impact the welfare of chickens by inducing chronic stress and cause economic loss for poultry producers by diminishing egg quality and production,” said Rik Koopman, DVM, Global Technical Director, MSD Animal Health. “The physiological stress caused by poultry red mite infestations, indicated by increased levels of the stress hormone corticosterone, has previously been studied only under lab conditions. We are pleased to share data from the first study of mite-related stress under field conditions that show the benefits of EXZOLT® for chickens and producers.” The study found EXZOLT® reduced physiological parameters of stress, including levels of corticosterone in the blood, feathers and eggs, as well as behavioral parameters, including head, body and wing shaking, head-scratching, preening plumage, gentle and severe feather pecking, aggression, and activity during the day and night. Hens showed a return to normal or improvement of stress indicators and a reduced incidence of comb discoloration, an indicator of blood loss, within a few days after the first application of EXZOLT®. Results were consistent across different housing systems, breeds and ages.

The 13-week study of approximately 180 hens on selected farms in Spain (n=20), Germany (n=15-30) and France (n=80-130) was conducted to evaluate the effect of EXZOLT® on red mite infestation-related stress in laying hens in different housing systems. Physiological, behavioral and health parameters of mite-related stress were measured before and after treatment with EXZOLT®.

Poultry red mites are a top-five cause of economic loss in European layer and breeder operations and in many other countries, as infestations cause significant stress to poultry, decrease reproductive potential in males, egg production in females and weight gain in young birds. The total annual cost of poultry red mite infestations in the European egg laying industry is estimated to be 360 million euros, with more than 430 million hens in all production types – pullets, breeders and layer hens – suffering from infestations.

About EXZOLT® (fluralaner)
EXZOLT®, a first-of-its-kind product based on the fluralaner molecule for the treatment of poultry red mite infestations, works on the parasites’ nervous system and kills mites that have taken a blood meal, while remaining safe for the host animal. Chickens are treated during an infestation. This ensures that both adult mites and their eggs are killed.
Clinical data from three European dose-confirmation studies and an extensive nine-site field study showed EXZOLT® provided virtual elimination of poultry red mite populations in all treated layer, breeder and/or pullet houses. In these studies, the recommended EXZOLT® dosage regimen (0.5 mg/kg body weight twice at a seven-day interval) achieved 99 percent mite-killing efficacy for at least 15 days, which spans two mite life cycles. EXZOLT® starts working in mites within four hours after mites start to feed on treated chickens, resulting in effective elimination of the mites.

Please see prescribing information for EXZOLT® at