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Control of Salmonella in Swedish cattle herds
Jonas Carlsson
Växa Sverige
Seminar at SLU in Uppsala
6 April 2017
Background
• In 1953 a severe domestic outbreak of S. Typhimurium involved more than 9000 people
• Since than the strategy has been to prevent Salmonella in all parts of the production chain
• When Sweden joined EU 1995 the Swedish control program was accepted and additional guarantees were achieved
• Around 3000 human cases is reported yearly and 75-80 % are infected abroad
Notified incidence of Salmonella in Swedish cattle herds during 1968-2015
Surveillance of Infectious diseases in animals and humans in Sweden 2015Report National Veterinary Institute, et al.
Short about the Swedish
Salmonella control program
• All findings of Salmonella is notifiableand actions is taken to eliminate contamination or infections
• Animal feed, the operators is responsible producing S-free feed
• Animals, investigations is required upon clinical suspicion
• Food, contaminated food products is considered unfit for human consumption
• Humans, salmonellosis in humans is notifiable and a trace back investigation is completed for all domestic cases
Surveillance in the Swedish
Salmonella control program
• Feed, focus on feed raw materials, heat treatment and prevention for recontamination
• Feed mills, sampling from the processing line and feed mill environment
• Food enterprises, in house control programs common
• Abattoirs, approx. 20 000 samples per year
• Cutting plants, approx. 5000 samples per year (red meat)
Control in cattle herds
• Compulsory part– investigations upon clinical suspicion– Sampling from postmortem investigations
– All imported animals are sampled
– When Salmonella is confirmed on a farm, the holding is put under restrictive measures, an investigation will be done and a plan to eradicate Salmonella is designed. Animals to and from the farm is stopped.
• Voluntary parts– Preventive biosecurity program
”Smittsäkrad besättning”
– Holdings affiliated to the program receive higher compensation in case of positive findings
• Developed 2011 - 2015 (state funded), launched in 2015
• Växa Sverige operates the program (assigned by the Swedish Board of Agriculture)
• Optional for farmers to affiliate, yearly fee 985 sek
To reduce the spread of infectious diseases between and within cattle farms
Which implies:- a positive effect on animal health
and animal welfare - a safe food production and a
reduced risk for spread of zoonotic diseases
- a reduced cost for the society and farmers regarding controlling infectious animal diseases
• State economic compensation in case of Salmonella
• Relevant education and advice -increased knowledge
• Different program levels
• Farmer-to-farmer communication
• User friendly solutions
• Group pressure
• Demand and/or decreased fee insurance companies
Web based biosecurity risk assessment questionnaire
Web based education
Controlled animal movementsBiosecurity advice service when planning new buildings for cattle
Veterinary inspection & advice
On-farm education
Web based biosecurity risk assessment questionnaire
Web based educationControlled animal movements
Veterinary inspection & advice
On-farm education
• Web based questionnaire regarding biosecurity routines and facilities of the farm
• Divided into 7 areas– Animal contact, visitors/staff,
transport/equipment, hygiene/health monitoring, feed, manure, surroundings
• Result after each section along with advice
• Results saved on the program page
• Repeated every 18-24 months
Web based biosecurity risk assessment questionnaire
Web based education part 1
Controlled animal movements
Veterinary inspection & advice
On-farm education
Based on:
- Results of the risk assessment
- Results of the checkpoints
Support to the veterinarians:
- Education
- Guidelines
- Access to notes from previous veterinary visits in the program
Web based biosecurity risk assessment questionnaire
Web based education part 1
Controlled animal movements
Veterinary inspection & advice
On-farm education
On-farm education
Focus course
• Workshops with owner and employees
• Motivation through education
• On farm – near the animals
• Practical exercises
Web based biosecurity risk assessment questionnaire
Web based education
Controlled animal movements
Veterinary inspection & advice
On-farm education
• Regulations in Smittsäkradbesättning for purchase of animals- From BVDV free herds- Born in Sweden (dairy herds)- Import controlled by SDS- Isolation on farm demand if
ingoing animals from > 5 herds
• Recommendations: use ”Säkerlivdjurshandel” in animal trade
• Subscription of milk analyses• Single sampling occasion kit• Health declaration forms• Advice for the seller/purchaser
Säker Livdjurshandel (SÄL)
= tools for safe animal trade
Subscription of milk analyses
Four samples/year on bulk tank milk• Salmonella
PrioCHECK® Salmonella Antibody bovine ELISA and PrioCHECK® Salmonella Ab bovine Dublin ELISA, Thermo Fischer Scientific
• Streptococcus agalactiae and Mycoplasma bovisThermofischer Pathoproof® Immuno Assay x-kit
Two samples/year on pooled milk from 3 primiparous cows (test milking scheme)• BRSV
SVANOVIR® BRSV-Ab
Four successive negative samples (Salmonella, M. bovis and Str. agalactiae) -> Green list Herds in milk recording have also info about BRSV-status (yellow=positive)
The Green list
• Farmers own declaration regarding the disease status of the herd, Eg. SCC, digital dermatitis, ringworm, parasites, symptoms of diarrea/cough
• Also to raise awareness of the risks involved in animal trading
Health declaration forms
Increasing costs due to:
• Increasing herd size
• In average longer time under restriction
• ”Epizootic attitude”
Herd size number of cattle
Skr
per
cat
tle
Average compensation from government per animalvs herd size for eradication of Salmonella (cases 1999-2013)
Source: The Swedish Board of Agriculture
Notified incidence of Salmonella in Swedish cattle herds during 1968-2015
Surveillance of Infectious diseases in animals and humans in Sweden 2015Report: National Veterinary Institute et al.
Results from serological screenings
for Salmonella on bulk milk
2007: 4% (S Dublin 1.3 %)
2013: 3% (S Dublin 0.9 %)
Source: National Veterinary Institute and Board of Agriculture
What´s the problem and there by
the challenge in future?
• More and more expensive eradications in relatively few herds, with little impact on national prevalence
• National screenings showed that ”the true prevalence” is much higher, there is normally no restrictions on these herds
• Concerning public health it seems that the additional guarantees is most important
Some thoughts for the future Swedish
Salmonella control program
• We have to be more cost-efficient in control
• Take full advantage of serological diagnostics
• Epizootic vs endemic perspective
• Secure animal trade not only for Salmonella but also for other relevant pathogens
• Spread knowledge, use an advisory service like in Denmark
• Avoid to overdramatize Salmonella
Pilot project
Testing the danish model of eradication of salmonella
• Biosecurity risk scoring protocol to identify critical infection routes
• Advice on action plan
• ELISA tests
• Follow-up