Exzolt Product Profile

Exzolt is a unique parasiticide for chickens that provides potent efficacy against Poultry Red Mites and Northern Fowl Mites via a convenient oral solution dosage form for administration in the drinking water.

  • Treatment with Exzolt provides fast, convenient, and potent acaricidal efficacy, with proven safety for chickens and the users of the product.
  • Exzolt is approved for treatment of Poultry Red Mite (D. gallinae) and Northern Fowl Mite (O. Sylviarum) infestation in pullets, breeders, and layer hens when provided in drinking water at 0.5 mg fluralaner/kg BW, administered twice 7 days apart.
  • Exzolt has a zero-day withdrawal period for chicken eggs and a 14-day (13-day in some countries, check your local regulations) withdrawal period for meat and offal, with no contraindications, known adverse effects or known interactions.

Mode of Action

Fluralaner (carbamoyl-benzamide-phenyl-isoxazoline), the active ingredient of Exzolt, is a member of the novel antiparasitic compound class of isoxazoline-substituted benzamide derivatives. Once ingested by a mite feeding on a treated chicken, fluralaner acts as a potent inhibitor of parts of the arthropod nervous system by acting antagonistically on ligand-gated chloride channels (GABA-receptor and glutamate-receptor).

The compound has demonstrated high activity on various heterologous GABA-receptors but shows no activity on the tested mammalian GABA-receptor.1 In vitro bio-assays have shown that fluralaner is effective against parasites having proven field resistance, including organophosphates (tick, mite), pyrethroids (tick, mite), and carbamates (mite).2

gaba receptor graphic

Fast, Potent Efficacy

Treatment of the host with Exzolt is an innovative approach to targeting mite parasites. Convenient treatment of poultry with Exzolt causes effective levels of the acaricide to be systemically distributed within all birds, ready to kill mites whenever parasites extract a blood meal from their hosts.

Efficacy against Poultry Red Mites (D. gallinae) and Northern Fowl Mite (O. sylviarum) begins within 4 hours after exposure of mites to treated chickens, and any mites feeding on treated chickens for at least 2 weeks after the first Exzolt administration will be killed.

With Exzolt, both types of mites’ life cycles are disrupted due to:

  • Rapid onset of fluralaner activity
  • High mite-killing efficacy (duration of at least 2 mite life cycles)
  • Absence of egg production from female mites exposed to treated chickens

When implementing comprehensive biosecurity measures, Exzolt also contributes toward long-term control of mite populations in a poultry house.

Safe for Poultry and People

Fluralaner offers high selectivity for arthropods such as Poultry Red Mites and Northern Fowl Mites, and Exzolt has a large safety margin demonstrated in chickens. While spraying comes with extensive precautions, Exzolt is safe for layers and has a zero-day withdrawal period for eggs. Both factors are vital in large poultry operations.

Exzolt also minimizes the potential for exposure of chemicals by human workers and reduces the workload compared to spraying. With Exzolt, house workers do not have to:

  • Remove birds and/or eggs
  • Repeat spray applications
  • Quarantine
  • Wear extensive safety equipment
  • Meet application license requirements

Fight Resistance with Exzolt

Mites developing resistance to control agents is an ongoing concern, as with most medicinal or chemical interventions. However, because fluralaner is a new agent recently introduced in veterinary medicine, no resistance has been detected thus far and is not a current concern.

The Exzolt Difference

Isoxazolines like fluralaner act at previously unrecognized activity sites without cross-resistance to other chemotypes, and effects differ between insects and mammals so toxicity is selective.3 In vitro bioassays have indicated that fluralaner offers efficacy against parasites with known field resistance to various chemical classes, including:

  • Organophosphates (tick, mite)
  • Pyrethroids (tick, mite) and
  • Carbamates (mite)

During dose confirmation and field studies conducted in support of Exzolt approval, 12 mite isolates were collected in 2014 and 2015 from 12 chicken houses in France, Germany, and Spain. The collected isolates were tested for in vitro acaricide sensitivity to fluralaner (11 isolates) and several other acaricides (not all tested for each isolate), with the following outcomes for various agents:4

  • Fluralaner: Isolates were highly susceptible to fluralaner with LC90 < 15.63 ppm.
  • Phoxim: Demonstrated variable sensitivity as 6 of 11 isolates had LC90 greater than the recommended concentration for chicken houses (2,000 ppm). The average LC90 for the 11 recent isolates was 3 dilutions higher than an older isolate collected in 2011.
  • Deltamethrin: 3 of 3 isolates tested had LC90 exceeding the recommended concentration for chicken houses (250 ppm).
  • Propoxur: 2 of 2 isolates tested had LC90 > 1,000 ppm.
  • Spinosad: 1 of 11 isolates tested had LC90 (> 4000 ppm) higher than the highest recommended concentration in the field (4000 ppm).

The Results

The Exzolt dosage regimen was designed to ensure effective treatment and elimination of all mite development stages from the flock, which limits resistance development. In addition, research showed that female mites dying after a blood meal from a fluralaner-treated hen were unable to lay any eggs, suggesting that the development of less sensitive mite stages from eggs is unlikely.5 Correct use of Exzolt according to label directions cannot be overemphasized, such as providing the full-approved dose regimen and estimating bird weights as closely as possible.

1   Gassel M, Wolf C, Noack S, Williams H, Ilg T. The novel isoxazoline ectoparasiticide fluralaner: selective inhibition of arthropod γ-aminobutyric acid- and L-glutamate-gated chloride channels and insecticidal/ acaricidal activity. Insect Biochem Molec Biol 2014; 45:111-124.

2   European Public Assessment Report (EPAR) for Exzolt. European Medicines Agency.

3   Casida JE. Golden age of RyR and GABA-R diamide and isoxazoline insecticides: common genesis, serendipity, surprises, selectivity, and safety. Chem Res Toxicol 2015; 28:560-566.

4   Thomas E, Zoller H, Heckeroth AR, Liebisch G, Flochlay Sigognault A. Comparative In Vitro Susceptibility Of Dermanyssus gallinae Field Isolates To Fluralaner, Phoxim, Spinosad, Deltamethrin And Propoxur- Proceedings of the WVPA 2017 Congress. Edinburgh, September 2017.

5   Data on file. MSD Animal Health.

Technical Manual

The development and approval of Exzolt (fluralaner) solution for treatment via drinking water now offers an unparalleled approach for management of poultry red mites in chickens. The Exzolt Technical Manual provides useful and comprehensive information about this cost-effective and revolutionary product.

Technical Manual