Environmental Assessment for Canadian licensing of Boehringer Ingelheim Vetmedica Inc.'s: Salmonella Choleraesuis - Typhimurium Vaccine, Avirulent Live Culture

March 2016

Prepared and revised by the Canadian Centre for Veterinary Biologics (CCVB) of the Canadian Food Inspection Agency (CFIA), this environmental assessment includes information that was current at the time of its preparation. It is possible, however, that the situation may have changed since that time. Please consult CCVB, if you have any questions.

Table of Contents

Summary

Salmonella Choleraesuis-Typhimurium Vaccine, Avirulent, Live Culture (Trade Name: Enterisol Salmonella T/C) consists of a live Salmonella Choleraesuis from the same master seed as vaccines which are licensed in Canada, Enterisol SC-54 and Enterisol SC-54 FF; plus a live Salmonella Typhimurium strain, which is assessed in this document. The vaccine is recommended for oral use in healthy, susceptible swine, 2 weeks of age or older, as an aid in the prevention of disease due to Salmonella Choleraesuis and Salmonella Typhimurium. The vaccine was evaluated by the Canadian Centre for Veterinary Biologics of the Canadian Food Inspection Agency, for licensing in Canada. As part of the requirements for licensing this product in Canada, an "Environmental Assessment" was conducted, and a public document containing information on the biological characteristics of the modified, live organism, the target animal and non-target animal safety, human safety, environmental considerations, and risk mitigating measures was prepared.

1. Introduction

1.1 Proposed Action: The Canadian Centre for Veterinary Biologics (CCVB) of the Canadian Food Inspection Agency (CFIA) is responsible for licensing veterinary biologics for use in Canada. The legal authority for the regulation of veterinary biologics in Canada is provided under the Health of Animals Act and the Health of Animals Regulations. Any veterinary biologic manufactured, sold or represented for use in Canada must comply with the requirements specified by the CFIA regarding the safety, purity, potency, and efficacy of the product. Boehringer Ingelheim (Canada) Ltd. has submitted an application to license the following vaccines in Canada:

  • Salmonella Choleraesuis-Typhimurium Vaccine, Avirulent, Live Culture (Enterisol Salmonella T/C) CCVB File No. 880VB/S10.0/B8.2, USDA Product Code 19A2.00, and
  • Salmonella Choleraesuis-Typhimurium Vaccine, Avirulent, Live Culture Frozen Form (Enterisol Salmonella T/C FF) CCVB File No.880VB/S10.1/B8.2, USDA Product Code 19A2.01

This Environmental Assessment was prepared by the CCVB as part of the overall assessment for licensing the lyophilized and frozen forms of this Salmonella Typhimurium vaccine, in Canada.

1.2 Background: Salmonella Choleraesuis-Typhimurium (S C-T) Vaccine, Avirulent, Live Culture is manufactured by Boehringer Ingelheim Vetmedica Inc. (BIVI), US Veterinary Biologics Establishment License No. 124, and is currently licensed for sale in the US in lyophized form and in frozen form. This vaccine consists of a live Salmonella Choleraesuis (SC) strain with the same master seed as licensed vaccines Enterisol SC-54 and Enterisol SC-54 FF; and a live Salmonella Typhimurium (ST) strain, Salmonella enterica subsp. enterica ser Typhimurium, which is assessed in this document. The vaccine is intended for oral use in healthy pigs, 2 weeks of age or older, as an aid in the prevention of disease due to SC and ST.

The vaccine was purchased from IDT GmbH, Germany which used this master seed in their ZOOSALORAL line of vaccines, for pigs and chickens.

2. Purpose and Need for Proposed Action

There are SC vaccines licensed in Canada, for use in pigs; however, there are no ST vaccines available, for use in pigs.

2.1 Significance: The labelling for these live, S C-T vaccines, indicates that they are recommended for the oral vaccination of healthy pigs, 2 weeks of age or older, as an aid in the prevention of disease due to both, SC and ST.

2.2 Rationale: The CCVB evaluates submissions for licensure of veterinary biologics under the Health of Animals Act and the Health of Animals Regulations. The general criteria for licensing are as follows: a) the product must be pure, safe, potent and efficacious; b) vaccine components must be relevant to Canadian disease conditions; c) foreign products must be licensed in the country of origin; and d) the product must be produced and tested in accordance with generally accepted "good manufacturing practices." These US origin vaccines meet the general criteria and thus were evaluated for licensing by the CCVB.

3. Alternatives

The two alternative options being considered are: a) to issue a Permit to Import Veterinary Biologics to Boehringer Ingelheim (Canada) Ltd., allowing the importation of these S C/T vaccines if all licensing requirements are satisfactory; or b) not to issue a Permit to Import Veterinary Biologics if licensing requirements are not met.

4. Biological Characteristics of Parent and Vaccine Organisms

4.1 Identification, Sources and Strains of Parental Organisms: The parental ST strain is a wild-type ST strain, originally isolated in Germany.

4.2 Description and function of attenuating change: This information is on file with CCVB. The attenuated strain is less competitive than the parent strain and has reduced survivability in the environment.

4.3 Method of Accomplishing Attenuation: The ST vaccine strain was developed in Germany at Leipzig University using chemical mutagenesis.

4.4 Phenotypic Stability of the Vaccine Organism: The current manufacturer, BIVI, USA, purchased the strain from IDT GmbH, Germany. They received this information from IDT GmbH:
The vaccine strain is distinguishable from the parent strain by gas chromatography. Plasmid analysis, ribotyping, IS200 typing and macrorestriction analysis can also be used (Schwarz S. and liebisch, B. 1994; Schwarz S. et al., 1995).
Reversion rates for the vaccine strain were unchanged after 10 sequential passages in vitro.

4.5 Horizontal Gene Transfer and Potential for Recombination: The vaccine strain does not contain any new genes.

ST can acquire genes through horizontal gene transfer and almost one quarter of the entire ST genome may have been introduced in this manner (Porwollik and McClelland, 2003). Since the vaccine strain's survivability is low, it is expected to die out within a short period, and is not expected to acquire virulence or resistance genes and persist as strain with increased virulence. IDT GmbH's data indicated no evidence of transfer of plasmids between field and vaccine strains over a 22 month period in chicken populations using the vaccine ZOOSALORAL H.

4.6 Host Range/Specificity, Tissue Tropism and Shed/Spread Capabilities: The wild-type strain can infect humans, domestic and wild animals and birds, causing disease. It has a tissue tropism for the small and large intestines. Shedding is intermittent but prolonged; "Once a pig is infected with Salmonella, it will carry and shed Salmonella intermittently at low numbers throughout its life" (Verbrugghe et al., 2011). "It has been estimated that 5–30% of finisher pigs originally infected may still excrete Salmonella at the end of the finishing period, and this percentage can double in periods of stress, for example during transport and lairage (Berends et al., 1996)."

The vaccine strain host range and tissue tropism are expected to be the same, while its shed/spread capability is expected to be lower. In a dissemination and transmission study in which 33 pigs, 2 weeks of age, were administered the vaccine organism and observed daily, no clinical signs were seen. There were some positive cultures from each of the organs sampled, indicating that the vaccine organism is invasive. Vaccinates shed intermittently until 28 days post-vaccination. No shedding was seen after day 31. The organism was not cultured from faecal swabs from sentinel pigs housed with inoculated ones, however, very few sentinels (no more than 6 at any given time) were used.

4.7 Comparison of the Properties of Vaccine Organism to Parent: The attenuated strain is less competitive and less capable than the parent strain, of survival in the environment.

4.8 Route of Administration/Transmission: Administration is by oral route, either by individual oral dosing or in drinking water.

5. Human Safety

This vaccine has not been administered to humans. There are no known, health risks to humans from consumption of meat from vaccinated animals or from administration of vaccine and handling waste from vaccinates. Health Canada's opinion was solicited and consequently label statements regarding human safety while handling vaccine, vaccinates and waste were added on the labels, as a precaution.

5.1 Previous Safe Use: The vaccine strain is used in vaccines 'ZOOSALORAL R' and ' ZOOSALORAL H' registered in Germany by IDT GmbH for more than 2 decades, with no reports of human safety issues.

The 2 forms of the vaccine currently under review have been licensed in the USA since July 2014. ST infections of humans are not uncommon, and use of this vaccine may lower the incidence of such cases, to some extent.

5.2 Probability of Human Exposure: Low from consumption of meat from vaccinated animals, since there is a withdrawal period.
Veterinarians and farm workers will have exposure to the vaccine strain while administering vaccine and also through direct contact with vaccinated animals and their feces.

5.3 Possible Outcomes of Human Exposure: There are no known risks to humans, and the vaccine strain is less invasive and persistent than the parent strain when injected into pigs. Some statements about precautionary measures for to minimizing exposure are on the label.

5.4 Pathogenicity of Parent Microorganisms in Humans: Pathogenic to humans.

5.5 Effect of Attenuation, on Pathogenicity in Humans: Pathogenicity is expected to be diminished. Vaccines using the same master seed have been in use in livestock in Germany for more than two decades.

5.6 Risk Associated With Widespread Use of the Vaccine: None identified, due to low survivability of the vaccine strain.

6. Animal Safety

6.1 Previous Safe Use: The vaccine strain is used in the vaccines 'ZOOSALORAL R' and 'ZOOSALORAL H' registered in Germany by IDT GmbH and in use for more than 2 decades.

6.2 Fate of the Vaccine in Target and Non-Target Species:
Target animals: Vaccine organism is shed intermittently for at least 4 weeks, and there is a possibility of spread.

In BIVI's dissemination and transmission study, there were some positive cultures from each of the organs sampled, indicating that the vaccine organism was invasive. Vaccinates shed intermittently until 28 days post-vaccination.

Non-target animals: BIVI Study 2012251 was completed in which rats, mice and chickens were inoculated with a S C-T vaccine dose comparable to the intended commercial pig dose and were evaluated for 14 days. There was minimal shedding and organ colonization.

In a study in chickens, a vaccine using this master seed remained avirulent and auxotrophic through 5 passages in day old chicks, carried out using organisms recovered from the liver of a chick in the previous passage (Schwarz S. et al., 1995).

6.3 Potential of Shed and/or Spread from Vaccinate to Contact Target and Non-Target Animals: Vaccine organism is shed intermittently for at least 4 weeks, and there is a possibility of spread. In BIVI's dissemination and transmission study was carried out in which 33 pigs, 2 weeks of age, were administered the vaccine organism. Vaccinates shed intermittently until 28 days post-vaccination but no shedding was seen after day 31. The organism was not cultured from faecal swabs from sentinel pigs, which were housed with inoculated ones, however, very few sentinels (no more than 6 at any given time) were used.

In BIVI's reversion to virulence study no clinical signs were seen at passage 1 in pigs. The vaccine organisms were not recoverable from the second back-passage as well as from the repeat second back passage.

6.4 Reversion to Virulence Resulting from Back Passage in Animals: In BIVIs reversion to virulence study no. 6131-1311-10P-024 ST with the master seed, no clinical signs were seen at passage 1 in pigs. The vaccine organisms were not recoverable from the second back-passage and from the repeat second back passage.
A publication by Schwartz et al., 1995, using Zoosaloral vaccine, demonstrated that the vaccine organism did not revert to virulence after 5 passages in day-old chicks.

6.5 Effect of the Vaccine in Target and Non-Target Species:
Target animals: In BIVI's dissemination and transmission study, 33 pigs, 2 weeks of age, were administered the vaccine organism and observed daily and no clinical signs were seen. There were some positive cultures from each of the organs sampled, indicating that the vaccine organism is invasive. Vaccinates shed intermittently until 28 days post-vaccination but no shedding was seen after day 31.

Non-target animals: BIVI Study 2012251 was completed in which rats, mice and chickens were inoculated with a S C-T ALC vaccine dose comparable to the intended commercial pig dose and were evaluated for 14 days. There were no adverse reactions to the vaccine exposure. There was minimal shedding and organ colonization. There were no lesions reported in any of the rats or mice; only one chicken had mild hyperemia in the colon at necropsy.

6.6 The Extent of the Host Range of the Attenuated Organism: Host range is expected to be as wide as for the parent. Spread is expected to be limited due to low survivability and reduced capacity to compete with wild-type organisms.

7. Affected Environment

7.1 Extent of Release into the Environment: Vaccine organism is shed intermittently for 4 weeks.

7.2 Persistence of the Vaccine Organism in the Environment and Cumulative Impacts: The attenuated strain's environmental persistence is greatly reduced from the parent strain.

7.3 Extent of Exposure to Non-Target Species: Exposure is expected to be low for mice; none to low for other animals.

7.4 Behaviour of Parent Microorganisms and Vaccine Organism in Non-Target Species: The parent organism is pathogenic in many animal species, including rodents, birds and humans.

The vaccine organism is not expected to be virulent. BIVI demonstrated safety in non-target animals by administering it to mice, rats and chickens.
Studies carried out in Germany were summarized but not submitted. These included 10 passages in mice; 5 passages in swine; and a chicken study carried out over 22 months.

8. Environmental Consequences

8.1 Risks and Benefits: The safety of this vaccine in target and non-target animals has been demonstrated. The benefit of the vaccine is its ability to aid in the prevention of the infection of pigs with wild type pathogenic ST and SC.

8.2 Relative Safety Compared to other Vaccines: There are no ST vaccines licensed for use in pigs in Canada.

9. Mitigative Measures

9.1 Worker Safety: The vaccine will be manufactured at BIVI, a veterinary biologics establishment licensed by the US Department of Agriculture. Individuals working with the vaccine, such as employees in the production facility, veterinarians, animal health technicians or poultry operators could be exposed to the live vaccine organism. The vaccine organism is not expected to be pathogenic.

9.2 Handling Vaccinated or Exposed Animals:

The following statements have been added to the label, as a precaution.

  • There are no known safety risks to humans, but workers should use protective equipment (gloves, mask) while handling the vaccine during administration and while handling farm wastes.
  • Measures to prevent accidental exposure of immunocompromised or vulnerable individuals should be taken.
  • Municipal and provincial regulations, as well as current Best Management Practices, should be strictly followed for appropriate disposal of the waste from vaccinated pigs.

10. Monitoring

10.1 General: The vaccine licensing regulations in Canada require manufacturers to report all significant suspected adverse reactions to the CFIA within 15 days of receiving notice from an owner or a veterinarian. Veterinarians may also report suspected adverse reactions directly to the CFIA. If an adverse reaction complaint is received by the CCVB, the manufacturer is asked to investigate and prepare a report for the owner's veterinarian and the CFIA. If the problem is resolved to the satisfaction of the veterinarian or client, usually, no further action is requested by the CCVB. However, if the outcome of the investigation is unsatisfactory, the CCVB may initiate regulatory action, depending on the case; this may include further safety testing, temporary stoppage of product sales, or product withdrawal from the market.

10.2 Human: No special monitoring of the human safety of the product will be carried out. Statements regarding additional human safety precautions were added to the label, and should be followed.

10.3 Animal: Veterinarians, vaccinators, and producers should report any suspected adverse reactions to the CCVB, using Form CFIA/ACIA 2205 – Notification of Suspected Adverse Events to Veterinary Biologics.

11. Consultations and Contacts

Manufacturer: Boehringer Ingelheim Vetmedica Inc. (BIVI)
Importer: Boehringer Ingelheim (Canada) Ltd.

12. Conclusions and Actions

Based on our assessment of the available information, the CCVB has concluded that the importation and use of Salmonella Choleraesuis-Typhimurium Vaccine, Avirulent, Live Culture (Enterisol Salmonella T/C) in Canada would not be expected to have any significant adverse effect on the environment, when manufactured and tested as described in the approved Outline of Production, and used according to label directions.

Following this assessment and the completion of the Canadian veterinary biologics licensing process, the Permit to Import Veterinary Biologics held by Boehringer Ingelheim (Canada) Ltd. may be amended to allow the importation and distribution of the following products in Canada:

Salmonella Choleraesuis-Typhimurium Vaccine, Avirulent, Live Culture (Enterisol Salmonella T/C) USDA Product Code 19A2.00, CCVB File 880VB/S10.0/B8.2 and Salmonella Choleraesuis-Typhimurium Vaccine, Avirulent, Live Culture, Frozen Form (Enterisol Salmonella T/C FF) USDA Product Code 19A2.01, CCVB File 880VB/S10.1/B8.2

All serials of this product must be released by the USDA prior to importation into Canada. All conditions described in the Permit to Import Veterinary Biologics must be followed with respect to the importation and sale of this product.

13. References

Summary Information Format for Conventional Live Veterinary Biologics (12/19/2013), Salmonella Typhimurium. Boehringer Ingelheim Vetmedica Inc. (Est. No. 124).

Ahmer B.M.M., Tran M. and Heffron F., 1999. "The virulence plasmid of Salmonella Typhimurium is self-transmissible" in J. Bacteriol. vol 181 (4): 1364-1368.

Berends B.R. et al., 1996 Identification and quantification of risk factors in animal management and transport regarding Salmonella spp. in pigs. Intl J of Food Microbiol vol 30 (1–2): 37–53.

Marcus S.L. et al., 2000. "Salmonella pathogenicity islands: Big virulence in small packages" Microbes Infect. vol 2 (2): 145-156.

Porwollick S. and McClelland M., 2003. "Lateral gene transfer in Salmonella." Microbes Infect. vol 5 (11): 977-89.

S. Schwarz and Liebisch B., 1994 "Use of ribotyping, IS200 typing and plasmid analysis for the identification of Salmonella enterica subsp.. Enterica serovar Typhimurium vaccine strain Zoosaloral H and its differentiation from wild type strains of the same serovar." Zbl. Bakt. 281, 442-450.

S. Schwarz et al., 1995 (translated from German) The complex characterization of salmonella strains for live vaccines – using an auxotrophic S. Typhimurium mutant as an example." Tierarztl. Umschau 50, 832-843.

Verbrugghe E. et al., 2011. Vet Res "Stress induced Salmonella Typhimurium recrudescence in pigs coincides with cortisol induced increased intracellular proliferation in macrophages." Vet Res 42(1): 118.

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