I: Purpose: 

Replication-defective adeno-associated virus (AAV) is a nonpathogenic organism commonly used as a viral vector in research applications. AAV is listed as a Risk Group 1 (RG1) agent by the NIH Guidelines and, under many circumstances, can be worked with at Animal Biosafety Level 1 (ABSL-1). When administered to animals, AAV may be shed in the urine or feces. To comply with NIH Guidelines requirements (App. G-II.) for the destruction of all recombinant organisms before release, all animal bedding with recombinant AAV must be decontaminated before disposal. 

II: Policy:

a) Housing

• Experiments containing replication-defective adeno-associated virus may be carried out in animals at Biosafety Level 1 (ABSL-1) unless:
• a helper virus is present (i.e. the AAV is replication competent) 
• the cargo encodes an oncogene or toxin.
  In such cases, animal experiments must be performed at ABSL-2. 
• This policy applies to all AAV administration routes, including intra-cranial, as AAV is known to cross the blood-brain barrier in multiple animal species, including rodents.
• Animals that are administered replication-defective AAV at ABSL-1 may be housed in reusable or disposable cages. 10% bleach or an approved vivarium disinfectant may be used for any AAV-contaminated supplies. However, 70% ethanol is not effective against AAV. 

b) Cage Changes Responsibility 

• Cages must be labeled to identify AAV-infected animals but do not require a biohazard sign.
• AAV-infected animals pose minimal shedding risk 72 hours post-injection. Accordingly, after administration of AAV to rodents, all cage changes within the first 72 hours and the first cage change after 72 hours must be treated as biohazardous: 
• All bedding and disposable cages must be disposed of as biohazardous waste and performed by laboratory staff.
• Reusable cages must be decontaminated prior to washing.  
• Following the first cage change after 72 hours, the AAV label may be removed from the cage, and vivarium staff may take over standard husbandry duties.
• Laboratory staff without access to autoclaves should double bag the bedding in red biohazardous waste bags and seal both bags with zip ties or autoclave tape. 
• The bags should be lightly sprayed with disinfectant and transported to the designated EH&S red biowaste drum as determined by the vivarium location.

III: References:

1. Assessment of Hazard Risk Associated with the Intravenous Use of Viral Vectors in Rodents. Reuter et al. 2012, Comparative Medicine 62:5
2. Biodistribution of rAAV following intraocular Administration – evidence for the presence and persistence of vector DNA in the optic nerve and in the brain. Provost et al. 2004, Molecular Therapy 11:2.
3. Preclinical Differences of intravascular AAV9 delivery to neurons and glia: A comparative study of adult mice and nonhuman primates. Gray et al. 2011, Molecular Therapy 19:6 (1058-1069).

Created 02/11/2020; Reviewed 02/12/2024