Vaccination - Uruguay

This very interesting report (March 2002) has just been received from the Uruguayan Embassy, by Ann Lambourne, it concerns their FMD outbreak and the vaccination programme. It is worth recalling the Minister, Elliot Morley's remarks to the Standing Committee on 4th December:

"My information is that prophylactic vaccination in Uruguay failed to eradicate the disease, and it is still endemic."
1. How then does one reconcile that with this from the Report?

in 1994 Uruguay was granted Disease Free Status with vaccination. It then stopped vaccinating in order to obtain DFS without vaccination, which it was granted in 1996. It was disease free until October 2000 when stamping out was applied. It again achieved DFS without vaccination in January 2001. However in April 2001 FMD struck again. Vaccination started in May after stamping out had failed to contain the disease.

The disease has extinguished in all 2057 affected holdings... The last focus of the disease was reported on 21st August 2001...and

On Tuesday 9th October 2001, the Veterinary Committee of the European Union proposed to the Commission to grant authorisation to Uruguay to resume meat production (cattle, sheep and goats) for the European Union. The Commission issued Decision 2001/767/CE, dated 31 October 2001, authorising to resume production as from 1st November 2001. Other markets have also lifted their restrictions and resumed importation of meat and meat products from Uruguay, e.g., Israel, Egypt, Polony, Hungary, Chile, Mercosur countries and other Latin-American countries.

2. We are now importing and consuming vaccinated meat from Uruguay again, but I don't hear any concerns raised about this by the very individuals who are claiming that UK consumers would not wish to buy UK vaccinated meat.

3. This report quite clearly states that serological testing revealed absence of the virus in Uruguay immediately prior to the outbreak, thus counteracting Morley's claim that it was endemic. It instead indicates that the disease must have been imported into the country, and suggests the most likely source.

On 23rd April 2001, a suspicion of FMD occurrence was reported. The Veterinary Services investigated and clinically confirmed the disease on 24th April 2001.

The official laboratory confirmed the diagnosis by serology, identifying antibodies against type A virus (VIAA and ELISA) on 25th April 2001.

The most probable hypothesis is that the virus was mechanically introduced from active outbreaks of the disease in the Republic of Argentine, in areas close to our border. This hypothesis is supported by the fact that the virus type identified is the same in both cases and cattle and other species susceptible to FMD from Argentine have not been introduced into Uruguay.

There are other very salient points:

The outbreak was tackled by stamping out to begin with, followed by ring vaccination because it had spread outside the original area. When it was found that the virus had already seeded in other areas of the country, a mass vaccination programme of the entire cattle population was quickly implemented. Thus the wide spread of the disease to many centres was used as the rationale for using mass vaccination and abandoning the culling. This contrasts dramatically with the arguments used by some scientists in this country who reiterate that the disease had spread too far for vaccination to have been of any use in bringing the disease under control. Uruguay illustrates quite dramatically how vaccination was precisely the tool to use in that situation, with the last case of the disease being in late August 2001, after vaccination was begun on 5th May. Notice the different strategies in the Contingency Plan. It would seem that Uruguay was very well prepared. How does our Contingency Plan stand up to that?

Actions taken

Immediate intervention, banning of animal movement and stamping out of the sick and in contact animal population susceptible to FMD, of affected farms within the outbreaks zone, was decided. It began on April 24th, 2001.

Immediate and voluntary discontinuation of Export Certification as from April 24th, 2001 as well as discontinuation of slaughter and production for export.

The ban on the movement and transit of animals was extended to all the country, on a national wide scale, as from April 27th, 2001, with the support, enforcement and back-up of the Police and Army due the powers and attributions of the DGSG. The response of the CCA (Competent Central Authority) was based on the National Animal Health Emergency Situation declared by Resolutions from the General Department of Livestock Services, and within the mandatory regulations provided by the Animal Health Legislation (Law Nº 3,606, dated April 13th, 1910 and Law Nº 16,082, dated October 4th, 1989).

On April 27, the epizootics outspread outside the original areas. The sanitary authorities decided to implement alternative 2 of the Sanitary Contingency Plan, including stamping out of affected animals and their contacts within the focus, ring vaccination and anticipated mandatory slaughter of all vaccinated animals.

Alternative 4 of the Contingency Plan was quickly implemented when FMD outbreaks were reported in other areas of the country. Alternative 4 includes discontinuation of stamping out and massive vaccination of the national cattle stock.

The second round of massive emergency vaccination (re-vaccination) began on June 15th and was completed on July 22nd 2001 providing, due to its booster effect, an expected 99 to 100% effective protection. This helped consolidate the mass population protection.

It is interesting to note how they dealt with sheep. Even though field testing of sheep showed evidence of viral activity, albeit at low levels, it seems that they were dismissed as not relevant.

Sero-epidemiological surveillance in FMD affected areas, carried out in August 2001 indicated that infection in sheep was lower than originally expected (7,684 samples were processed, with 206 VIAA positives, a prevalence of 2.7%).

These results indicate that the animals had been exposed to infection but the Uruguayan authorities considered that the low prevalence demonstrated that sheep did not play a role in the epidemic.

Instead the authorities focused on other agents of disease spread, and reported:

The Departments of Soriano and Colonia have a mixed farming system, combining milk and meat production with intensive agriculture. This system involves intense movement of trucks, machinery and persons. This is an important factor contributing to viral spread (high contact rate and higher probabilities of massive mechanical spread). The investigation carried out suggests that the latter was a determinant factor in the spread of the disease.

I think the UK would have been far better advised in concentrating its attention on the dangers of the above-mentioned methods of disease spread, instead of mass culling to clear great swathes of countryside of sheep, an operation which in itself resulted in spread, with all the personnel, vehicles, machinery involved. It seems that the Uruguay veterinary officials managed to come up with a sensitive, risk-based assessment of disease spread using veterinary and not mathematical principles.

Another interesting point is the protection level achieved by vaccination. Again this report counters claims by UK scientists.

A serological sampling of cattle was carried out in September 2001, with the aim of estimating the protection level achieved with vaccination.

The results suggest that an estimated protection level of 99.6% was achieved.

At present, we can assure that the disease has been controlled, the strategy applied has been successful, the vaccines used were appropriate and the emergency actions were positive. In fact, during the last 213 days, no new focus has been reported.

Finally, it is interesting to note the lack of fuss about vaccinating such large numbers of cattle (11 million I think). The report makes a brief statement that all has been achieved, and then gives details of the programme.

Report on the February 2002 vaccination

According to the FMD eradication strategy carried out in Uruguay, between 1st and 28th February 2002, the whole cattle stock was vaccinated.

As in previous cases, vaccination Control Routes were established and the farmers were assigned a date and time to apply the vaccine. Therefore, a direct control was carried out, as shown in the following table....

All the vaccine doses used since the beginning of the Vaccination Programme have been provided to the farmers by the Ministry of Livestock, Agriculture and Fisheries, free of cost.

Ann Lambourne

To read the report click here!