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

Smittsäkrad

besättning

A biosecurity program

for cattle herds in

Sweden

• 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

Linked to hands on advice for each area

at www.smittsakra.se

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

A program for safe 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

Green list gives also info about how many contact herds latest 12 month

• 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

Thank you for listening!and special thanks to

Sofie Andersson & Anna Ohlson