Tbphases.doc
STRATEGICAL PHASES OF BOVINE
TUBERCULOSIS ELIMINATION AT NATIONAL LEVEL
V. Kouba
Former Czechoslovak and Czech Chief Epizootiologist,
(Provisional text to be finalized and edited)
1. Introduction
First report about the occurrence of
tuberculosis in cattle caused by Mycobacterium bovis in the territory of future
Note: The programme was
called “elimination” (to reach zero prevalence) and not “eradication” (to reach
complete disease disappearing) due to the fact that M.bovis was exceptionally surviving among human population.
2. Strategic phases
National bovine tuberculosis elimination
programme initiated in 1956 lasted 12 years. It was subdivided in 5 basic
phases:
experimental phase – 1956-1958,
preparatory
phase – 1958-1959,
starting
phase – 1959-1960,
main attack phase – 1960-1967 and
final elimination phase – 1968.
Post-elimination period followed from 1969.
3. Experimental phase
- orientation investigations of epizootiological situation in cattle
tuberculosis
- testing of different elimination and eradication methods
- testing vaccines against bovine tuberculosis (BCG, M-vaccine)
- testing tuberculin (Old, PPD) and their results’ interpretation
- study of national and international publications on and experience in
cattle tuberculosis control
- analyses of bovine tuberculosis impact on human health, animal
production, livestock husbandry development, trade, etc. demonstrating catastrophic
situation in the country
- first specific postgraduate courses for veterinarians
- meetings of specialists and veterinarians at all levels discussing
bovine tuberculosis situation, problems and elimination feasibility
- campaign for convincing veterinarians, farmers, public and government
decision-makers on bovine tuberculosis elimination necessity and feasibility
-publication of first monograph on bovine tuberculosis
General Supporting measures:
- consolidation and strengthening of government veterinary services in
terms:
of infrastructure, manpower, diagnostic laboratory facilities,
tuberculin and specific instruments’ production capacities, material,
transport, communication, funds, etc.
- establishment of a new Department of Epizootiology at both
Universities of Veterinary Sciences (in
- establishment of Epizootiology
as a new subject in undergraduate curriculum and as final state exams component.
4. Preparatory phase
- declaration of bovine tuberculosis elimination as the priority for
veterinary and livestock services
- government decision on bovine tuberculosis elimination during one
cattle population generation to achieve zero prevalence
- issuing ant-tb legislation, directives and instructions for complex
preventive and eradication measures and specific surveillance
- establishment of government financial subsidies system complemented
by insurance agency contribution
- issuing standards for tb diagnosis (allergic and laboratory)
including uniform interpretation of the results
- elaboration of long-term programme with clear cut objectives in all
ranches, regions, provinces and at national level
- starting the production of a new PPD tuberculin
- obligatory special training of all government veterinarians starting
with provincial and regional Chief Veterinary Officers to assure uniform
application of anti-tb method
- production and distribution of anti-tb extension material attracting
public, farmers and decision-makers support
- establishment of special surveillance, monitoring, reporting and
information system with special forms and data processing (including uniform
epizootiological indicators and mapping)
General supporting measures:
. establishment of a network of provincial and regional epizootiologists
managed by national chief epizootiologist
- building dense veterinary
diagnostic laboratories’ network
- building a central veterinary
research institute
- building veterinary sanitation
institutes’ network
- establishment of an institute for postgraduate veterinary training
- establishment of an institute for veterinary extension (including printing facilities)
5. Starting phase
- prohibition of anti-tuberculosis vaccination of domestic animals
- allergic testing and registration of all cattle herds and their
epizootiological classification according to tests results
- adjustment of anti-tuberculosis methods and plans according to newly
discovered situation
- starting all anti-tuberculosis programmes at all levels
- all positive cattle ear-marked without further tuberculin testing
- culling tuberculosis cattle in ranches with low prevalence
- starting massive anti-tuberculosis extension activities
- starting annual anti-tuberculosis postgraduate training of veterinary
service regional and provincial chief officers and epizootiologists
- introduction of obligatory pasteurization of cow milk before
distribution
- complementing veterinary service material provisions
6. Main attack phase
- executing anti-tuberculosis preventive and eradication programmes at
all levels
- temporary adjustment of cow milk and beef production and purchase to
assure national planned milk and beef consumption without reducing country cow
population: increasing beef production and purchase plans in highly affected
regions and provinces giving them chance to cull higher number of tuberculosis
cows and simultaneously decreasing them the milk production plan while opposite
approach was applied in tuberculosis free or with very low prevalence regions
and provinces
- organization of healthy heifers’ (of good genetic quality and usually
pregnant to can start new production process) transfers into tuberculosis
affected provinces, regions and ranches for the replacement of tuberculosis cattle
- systematic tuberculin testing of all cattle herds (e.g. cows twice a
year)
- culling all tuberculin positive cattle with follow-up sanitation –
disinfection of infected environment
- systematic postmortem investigations of all slaughtered domestic
mammals
- declaration and visible marking (gate tables) of tuberculosis-free
ranches
- provision of subsidies for covering losses due to tuberculosis cattle
premature elimination (difference between prices) to maintain cattle producers
income and standard of living
- intensive bovine tuberculosis surveillance in animal and human
populations
- establishment and running tuberculosis isolation ranches/farms for
temporary exploitation of selected high milking
cows affected by the diseases concentrated from different ranches and regions
finalizing the elimination programme
- regulation of anti-tuberculosis programmes to gradually reduce
population prevalence and to restrict tuberculosis affected territory
- continue with annual anti-tuberculosis postgraduate training of all
regional and provincial chief veterinary officers and epizootiologists
- complex epizootiological and laboratory investigations of all new outbreaks
and suspicions in to date tuberculosis free herds
- continuing monitoring and evaluation of anti-tuberculosis programmes’
execution and results with follow-up adjustment when and where necessary.
7. Final elimination
phase
- culling of all resting tuberculosis cattle in the country
- abolishment of last tuberculosis isolation ranches/farms
- sanitation – disinfection of the last affected ranches/farms
- final evaluation of tuberculosis elimination programme impact
- biological
- economic
- public health
- social
- final evaluation of cost/benefit of bovine tuberculosis elimination.
Preparation of post-elimination period
- adjustment of the methodology of specific tuberculosis surveillance
- decision on immediate
application of radical method for any eventual new cases
- adjustment of information system
- adjustment of veterinary services organization and management
- starting research of tuberculin non-specific reactions
- publication of results and experience.
8. Post-elimination
period
- realization of long-term post-elimination surveillance programmes
- continuation of systematic allergic investigations of all cattle herds
- epizootiological and allergic investigations of cattle in critical
places and moments (e.g. in quarantines, before and after transfer between
ranches)
- complex epizootiological and allergic investigations in cases of
bovine tuberculosis suspicion in domestic animals
- complex epidemiological and epizootiological investigations in cases
of M. bovis suspicion in humans
- increasing proportion of simultaneous tuberculin tests to distinguish
allergic reactions due to M. bovis
and M. avium
-strict post-mortem control of all slaughtered cattle
- use of laboratory investigations (incl. typing) in case of bovine tuberculosis
suspicion
- application of only radical method when and where new cases of bovine
tuberculosis appear
- significant restriction of cattle import (thanks also food
self-sufficiency achieved by bovine tuberculosis elimination)- very strict
import conditions regarding bovine tuberculosis free status and diagnostic
control
- allergic, post-mortem and epizootiological investigations on bovine tuberculosis
in other domestic mammals
- continuation of close collaboration between veterinary, public health
services (committee for anthropozoonoses, publishing common yearbook called
“Surveillance of anthropozoonoses”, etc.) and livestock services (helping
regulate national cattle population reproduction process).
More information in http://vaclavkouba.byl.cz/tuberculosis.htm