Parapox ovis virus immunomodulator
**Parapox ovis virus immunomodulator** is a biologic immunostimulant primarily used in veterinary medicine to boost the non-specific immune response. Key characteristics include: * **Paramunity Inducer**: It utilizes an inactivated (killed) virus that originally causes 'orf' (contagious pustular dermatitis) in sheep. * **Equine Application**: In the US, it is labeled for healthy horses (4 months and older) to aid in reducing upper respiratory disease caused by **Equine Herpesvirus types 1 and 4 (EHV-1 and EHV-4)**. * **Reproductive Use**: Off-label, it is utilized in equine reproduction protocols for broodmares with delayed uterine clearance (DUC) or hyper-responsive uteri. * **Small Animal Use**: While not labeled in the US for small animals, similar products (e.g., Baypamun®) have been used in Europe for dogs and cats to stimulate non-specific immunity during viral infections or stress. > **Clinical Pearl**: Because the virus is inactivated, it cannot cause disease in the treated animal. It serves purely as a decoy to wake up the host's innate immune system.
Mechanism: The drug acts as a **paramunity inducer** through a process known as **viral interference**. * **Mechanism**: The inactivated parapoxvirus "infects" host cells with a defective, non-replicating viral particle. * **Immune Activation**: This pseudo-infection $\rightarrow$ triggers the host's innate immune system $\rightarrow$ leading to the induction and release of **interferons**, **cytokines**, and **colony-stimulating factors**. * **Cellular Response**: It also stimulates the activation of **natural killer (NK) cells**, which help clear pathogenic viruses before they can establish a robust infection.
Dosing by species
- Aid in reducing upper airway disease caused by herpesvirus types 1 and 4 · 2 mL IM · IM · Repeat doses on days 2 and 9 following the initial dose · 3 doses total · Retreatment is recommended during subsequent disease episodes or prior to stress inducing situations.
- Hyper-responding or delayed uterine clearance (DUC) broodmares · A single IM dose · IM · Once · The day before breeding · Followed by 12 mg of dexamethasone sodium phosphate IV at the time of breeding and 1 mL (20 Units) oxytocin and 1 mL (250 micrograms) estradiol with or without uterine lavage 6 hours later.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Contraindications
- Prior hypersensitivity to the agent
Adverse effects
- Anaphylaxis (rare but possible)
Monitoring
- Clinical efficacy (improvement in respiratory infection signs or uterine clearance)
- Signs of anaphylaxis or hypersensitivity immediately post-injection
Overdose
No specific information is available regarding acute toxicity or overdosage. Given its nature as an inactivated biologic, massive toxicity is unlikely, though the risk of immune-mediated or injection-site reactions may increase.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.