Lessons in control of Foot and Mouth Disease

                                   

The ongoing pandemic has added many words to the vocabulary of common man which earlier he was not aware of. Now people know and freely use words like virus, corona, strain, sub strain, variant, mutant, double mutant, immunity, immunity booster, vaccine, booster dose, efficacy, Covid-19 and even herd immunity. They also know various names of vaccines that are available to provide immunity against corona although its guarantee or duration is not exactly known even to the scientists. 

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The first time I heard these terms was when as a student in Veterinary College I studied subjects of Bacteriology ( including virology, immunology ) in 1967 followed by Veterinary Medicine in 68. 

As students we studied Foot & Mouth Disease (FMD) caused by virus and affecting all cloven footed animals. This virus exists as seven immunologically distinct serotypes and each has subtypes formed due to mutations. Further, we learnt  that in dairy cattle it causes huge economic losses due to severe drop in milk production and problems of breeding thereafter. In case of working bullocks the disease makes them lame and unfit for work for several days. We were taught that to control the disease it was  important to carry out vaccination twice in a year on a wider scale since the FMD virus being air borne  it spread quickly from village to village through infected animals and non-animate objects like fodder, vehicles etc. The Indian Veterinary Research Institute had produced a vaccine incorporating four strains of FMD virus identified as A, O, C and Asia 1. 

Now something about this disease in brief. As the name suggests, when animal gets infected with the virus there are lesions in mouth as well as in hooves. There are ulcers on tongue and gums which turn into painful blisters containing fluid. In cows the blisters may appear on the udder as well. Similar lesions appear on the skin fold between the hooves. Soon these blisters rupture resulting in wounds  and animal is unable to chew or ruminate the coarse food and goes lame. The animal goes off feed and in lactating animals milk production suffers for entire lactation. In the case of bullocks they are unable to work in field or pull a cart. The virus spreads through the fluid oozing out of mouth as well as from hooves. It takes several days or weeks for these animals to come back to normal feeding or working. The after effects, however, continue over several months with problems is breeding and general health. The disease affects all types of cattle and buffaloes, sheep, goats, pigs and in case of young calves lesions in heart are noticed. Although death occurs only in severe cases the other symptoms cripple the animals leading to economic losses said above. 

The second time I heard or rather had encounter with FMD was in 1972  when I joined NDDB and underwent training in Amul Dairy. When I went on mobile veterinary routes, I came across number of cases of FMD and  in some villages witnessed a situation almost like an outbreak. I saw hundreds of buffaloes suffering and the only treatment was first aid with glycerine and boric powder to avoid secondary infection; since there  is no treatment as such for the disease.

However, It was  around 1980 that I really came to know more about FMD and most importantly about its control in the field conditions. That time I was posted in NDDB Regional Office at Bangalore and the FMD Control Project  (FMDCP) was launched in southern peninsula. Actually it was a two-pronged approach, one was to step up use of FMD vaccine in the field progressively and produce a disease free status AND the second objective was to sustain the requirement of adequate vaccine by establishing additional capacity to produce FMD vaccine incorporating the required strains of virus as may be found necessary with first hand experience in field on a wider scale. The action was initiated from Ooty !

Now when I look forty years back I feel astonished as to how one animal disease was addressed by NDDB in the most scientific manner so as to control the disease and save the animal, the farmer, and the economic loss and while keeping the national interest on top of it. It was then estimated that the annual loss on account of FMD was to the tune of  Rs 1200 crores at all India level. A situation like that was not affordable for our agricultural economy and thinking about future it also would have posed problems in export of Indian dairy products. Unless you had massive vaccination program and produced a disease free status any export was unthinkable. Thus, a concept of disease free zone had emerged against FMD and NDDB had taken up the project facing all the related issues squarely. 

I would like to mention here the salient features of that project for the benefit of readers new to FMD as well as for many to understand the issues involved in controlling any contagious disease caused by virus whether in animals or in human beings.

The NDDB’s objective was to create a sort of disease free zone as far as FMD was concerned and therefore peninsular region was taken as project area. Ooty, a famous hill station ( later on named as Vathagamandalam ) in Tamil Nadu was selected as headquarter to receive and store the required vaccine, monitor the project and carry out laboratory analysis of the samples received from project area on continuous basis. For this purpose in a short span a full fledged laboratory was established on a piece of land provided by Govt. of Tamil Nadu.

Beginning from Ooty the project area comprising 23 districts was to be covered in concentric manner increasing the periphery in each phase. As the periphery increased the project extended into the area of other states namely Kerala, Karnataka and Andhra Pradesh. Given these conditions the project needed full support and cooperation from the Animal Husbandry Department (AHD) of each state. 

For this to happen directives from Govt. of India were absolutely necessary and they were sought. Accordingly the state governments made the Animal Disease Control Act applicable by gazette notifications declaring the concerned districts where FMD vaccinations were made compulsory for all cattle, buffaloes, pigs, sheep and goats. Each vaccinated animal was also to be ear-tagged with a permanent plastic tag having unique identification number which enabled the project authority to follow it up with next round of vaccination and also for collecting blood for serum analysis when selected randomly. 

From outside the district movement of animals was also checked at the posts established at the entry point of the district. It was made compulsory that the animal should have been vaccinated at least 14 days prior to the date of entry. In addition, all the animals coming to market yard or in weekly cattle markets were vaccinated compulsorily. This was carried out by the staff of the AHD. 

The  NDDB had appointed Dr. M. Poornachandra Rao as Officer on Special Duty. He had retired as Executive Director in Andhra Pradesh Dairy Corporation with previous experience in AHD.  

Dr.S. Ramkrishnan who was Zonal Manager in Tamil Nadu Dairy Federation, came on deputation to help in project implementation. There was one expert from UK stationed at Ooty to provide guidance. Few scientists and a Virologist were appointed to run the laboratory. However, to carry out actual vaccinations in animals a large number of vaccinators and helpers were necessary and it was not possible to create permanent positions. As an alternative they were appointed locally on contract basis and trained in batches. ( A certificate towards the end of program was promised.)  The helpers were arranged through dairy societies organized under OF, and where there was no society through Gram  Panchayat. The vaccinators and helpers were paid basic remuneration and on the basis of actual number of vaccinations carried out by them. This approach offered them good incentive and had positive effect on achieving the targets. For mobility of vaccinators the project provided motorcycles and paid maintenance cost.

To implement this vaccination program over a wide area of 23 districts and also over a span of several years  a consistent flow of appropriate vaccine was absolutely necessary. The capacity of the then existing units in our country was limited. Accordingly arrangements were made with Wellcome Foundation, UK to obtain adequate vaccine during the entire project period which was as Aid from Oversees Development Administration. Assistance was also sought from FMD  World Reference Laboratory ( WRL ) at Pirbright UK for typing of strains/ sub strains encountered in the field from time to time as and when there was outbreak anywhere in project area. 

Cold chain was very important to keep vaccine between 4 and 8 degree Celsius till it was injected in animal body. Accordingly cold storages, refrigerators, and supply of ice were arranged so that vaccinators carried vaccine in the field at ideal temperature in insulated boxes. 

Vaccinations were carried out in each revenue village and all hamlets in its jurisdiction. All Primary Milk Producers’ Societies and District Cooperative Milk Unions under OF participated in the exercise and their infrastructure like Milk Chilling Centre was put to use. The villages in forest area were also covered. The actual data collected during last Animal Census was used as a guideline while trying to cover hundred percent cattle and buffaloes and also other vulnerable stock like sheep goats and pigs. The number of animals thus covered was compared with census figures to work out percentage of herd  covered for protection against FMD. Parallel arrangements were made to randomly collect blood samples from vaccinated animals post 14 days from all villages to know the immunity level achieved by vaccination. The inferences were drawn on village basis as well as they pertained for each vaccinator. So their was a sort of surveillance on the vaccinations carried out. 

In spite of series of vaccinations as and when there was FMD outbreak, immediate arrangements were made to quarantine the village animals and collect tissue samples for laboratory analysis and for referring to WRL Pirbright for typing of the strain. Simultaneously to stamp out the disease the entire population of cattle, buffaloes and pigs within the radius of few kilometers was vaccinated again.

With this approach the FMDCP was implemented in number of phases spread over many years. 

I was in NDDB Regional Office, Bangalore till March 1985 and can say that the project was achieving desired results as more and more districts were covered and periphery increased from Ooty. Although I don’t remember exact figures but can say that beyond 80% animals were covered by vaccination and protected against FMD in the area covered by the time I left Bangalore.

Under the two-pronged approach of NDDB as referred to above, the other part was to establish additional capacity to produce FMD vaccine. Accordingly at Gachchibowali, Hyderabad a Vaccine plant was erected by NDDB in 1982 and it was run as a unit. It was corporatized as Indian Immunologicals Ltd. ( IIL )in 1999. Now in 2021 it is engaged in producing several vaccines as Animal Health products and also Human Health products.  What more, it is the World’s largest manufacturer of FMD vaccine producing 360 million doses per year ! The FMD Control Project started in Ooty way back in 1980 has also continued till this day with more and more budgetary support from the Govt. of India covering all the districts in India. 

And last but not least, from its website one finds that the IIL is presently in tie up with Australia’s Griffith University for COVID-19 vaccine research that is expected to provide long-lasting protection with a single dose administration to we people.

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