ABOVE: DAFF notice of possible importation of live attenuated salmonella vaccines for use in chickens and turkeys. Photo: Victor Talashuk
This notice affects stakeholders who have an interest in the possible importation of live attenuated salmonella vaccines for use in chickens and turkeys.
The application
The Department of Agriculture, Fisheries and Forestry has received a permit application from Elanco Australasia to import the following live attenuated veterinary vaccines:
- AviPro Salmonella Duo
- AviPro Salmonella Vac E
- AviPro Salmonella Vac T.
The application is being assessed against the requirements of Australia’s current import policies and guidelines for live veterinary vaccines:
- Australian Quarantine Policy and Requirements for the Importation of Live and Novel Veterinary Bulk and Finished Vaccines, November 1999
- Guidelines for managing the risk of transmitting transmissible spongiform encephalopathies via veterinary vaccines and other in vivo veterinary products, October 2012
- Assessment of genetic recombination and re-assortment of imported veterinary vaccines, July 2018.
Summary of product information
Vaccines are presented as a lyophilisate for suspension.
AviPro Salmonella Vac E
Live attenuated salmonella enteritidis bacteria, strain Sm24/Rif12/Ssq.
AviPro Salmonella Vac T
Live attenuated salmonella typhimurium bacteria, strain Nal2/Rif9/Rtt).
AviPro Salmonella Duo
Live attenuated salmonella enteritidis bacteria, strain Sm24/Rif12/Ssq and live attenuated salmonella typhimurium bacteria, strain Nal2/Rif9/Rtt).
AviPro Salmonella Duo is a live attenuated vaccine combining the strains of salmonella in AviPro Salmonella Vac E and AviPro Salmonella Vac T.
Target species
Chickens (breeders and layers) and turkeys (breeders and meat production).
Route of administration
For administration after resuspension via the drinking water.
Manufacturer
Lohmann Animal Health GmbH, Heinz-Lohmann Str. 4, 27472 Cuxhaven, Germany.
Indications for use
For active immunisation of healthy and susceptible chickens to reduce faecal excretion and colonisation of internal organs with salmonella enteritidis and s typhimurium field strains and to reduce colonisation of eggs with s enteritidis field strains.
For active immunisation of healthy and susceptible turkeys to reduce colonisation of internal organs with s enteritidis and s typhimurium field strains.
The AviPro Salmonella vaccines contribute to the reduction in the prevalence of salmonella input into the human food chain via avian products.
Mechanism of attenuation
The vaccine strains are natural metabolic drift mutants, that is they lack or do not express certain metabolic pathways which results in attenuation.
The genetic basis results in defective ribosomal protein S12 affecting polypeptide synthesis (streptomycin resistance), defective gyrase affecting DNA replication (nalidixic acid resistance) and defective RNA polymerase affecting transcription of DNA to RNA (rifampicin resistance).
The vaccine strains also have attenuations that increase the permeability of the cell membrane for harmful agents such as detergents and antibiotics.
This means that the strains have poor survival in the environment and are highly sensitive to fluoroquinolones and unlike field strains are sensitive to erythromycin.
Withdrawal period
Meat, offal and eggs – 21 days.
Endemicity
An analysis of whole genome sequencing of the AviPro vaccine strains confirmed that sequences were homologous to those isolated in Australia from non-travel associated human cases.
If a permit were issued to import these vaccines, DAFF has assessed the level of risk to Australia’s trade in avian products to be very low. Photo: Finn Mund
Risk of reversion to virulence
It has been determined that the risk of vaccine strains reverting to a virulent state is very low following an assessment of the mechanism of attenuation and associated mutations of the vaccine strains, as well as a review of test reports demonstrating stability of the vaccine strains.
There are also a variety of independent published reports with a satisfactory view on the likelihood of reversion to virulence.
The applicant has provided data on the volume of international vaccine sales in markets with animal disease reporting systems equivalent to those in Australia.
This data demonstrates a safe history of use of the vaccine over a significant timeframe.
Risks of genetic recombination and reassortment
The importation and use of live bacterial vaccines may be associated with a risk of genetic recombination between vaccines strains and other strains already circulating in Australia.
This can lead to disease events caused by strains of the agent that demonstrate increased pathogenicity through the introduction of mutations or virulence factors that currently do not exist in Australia.
While the likelihood of this occurring is low, it has been confirmed in published research that recombination involving live veterinary vaccines has occurred under Australian field conditions.
DAFF has done an assessment of the risk of inter-genomic recombination of the salmonella vaccine strains as well as between vaccine strains and indigenous strains circulating in Australia.
This assessment considered evidence provided by the applicant as well as other published studies.
It was determined that the likelihood of disease outbreaks resulting from recombination or reassortment events resulting from the importation of the AviPro Salmonella vaccines was very low.
Potential impacts on trade
DAFF has assessed the level of risk to Australia’s trade in avian products to be very low if a permit were issued to import these vaccines.
What’s next?
DAFF will continue assessing biosecurity risks associated with the importation of the AviPro Salmonella vaccines, including an assessment of the quality management system of the overseas manufacturer.
If the assessment determines that the level of biosecurity risk associated with the importation of the vaccines is very low then a permit will be issued to import the goods.
Further information
If you require further information, call 1800 900 090, email imports@aff.gov.au or visit agriculture.gov.au/biosecurity-trade/import/industry-advice/2024/70-2024