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Monitoring, surveillance and forecasting of infectious animal diseases in India.

Introduction

India has a fast growing livestock sector and home to 512 million domestic animals. Livestock and poultry sectors play a critical role in welfare of India's rural population and contribute significantly to the agro-based economy of India. Together with the fisheries sector, it accounts for nearly 29.0% of the value of output from total agriculture and allied sectors and contributes about 5.26% to the National GDP. This sector is emerging as an important growth leverage of Indian economy. As a component of agricultural sector, its share in gross domestic product has been rising gradually at a rate of about 5.0% per year, which is higher than the growth in agriculture. This enterprise provides a flow of essential food products, draught power, manure, employment, income and export earnings. Distribution of livestock wealth is more egalitarian as compared to land. Hence from the equity and livelihood perspective, it is considered an important component in poverty alleviation programs.

Though there has been a steady increase in contribution of this sector to National GDP, the real potential of this sector remains to be realized. Diseases of livestock can cause major losses, both to livestock owners and country as a whole. In many developing countries including India, outbreaks of major diseases occur frequently and are poorly controlled, resulting in large numbers of deaths. Diseases that are chronic or subclinical in nature may also cause high losses through decreased fertility, decreased weight gain and inefficient use of feed or inability of animals to work. In addition, zoonotic diseases (diseases affecting both animals and humans) may have an important impact on public health. Without accurate surveillance data, it is difficult to understand the true health status of animal population. Inadequate surveillance and consequent 'blindness' to health status of population has contributed to uncontrolled global spread of diseases in the past. Thus effective surveillance of animal diseases and protection of animal wealth through exclusion and containment of existing, emerging as well as transboundary or exotic diseases are a prerequisite for sustainable livestock production.

The epidemiological disease surveillance is a dynamic process involving the infectious agent, host, reservoirs, vectors and environment. Disease surveillance has long been recognized as an important tool for measuring the disease burden, studying morbidity, mortality trends and early detection of outbreaks for instituting effective control measures in timely manner.

The trade in animals and animal products has expanded dramatically over the last decade and will continue to increase. Political changes in world over and world trade agreements opened new markets for a wide variety of livestock products. However, the increased potential for international trade places additional constraints on both importing and exporting countries with regard to disease surveillance and monitoring of animal health.

Disease Surveillance in India

The protection of animal health is the responsibility of State Governments. Government of India through Department of Animal Husbandry, Dairying and Fisheries (DADF) is responsible for coordination and control of animal diseases at national level, while Indian Council of Agricultural Research (ICAR) through Animal Science Division is responsible for animal diseases research, diagnosis and their control.

Currently in India, the main method of collecting information on livestock diseases is through a passive disease reporting system. When an animal is noticed sick, the owner may contact the Veterinary authorities, who may then either submits a disease report or send specimen to a diagnostic laboratory. As such in this system, the information is not collected about all cases or all diseases and the population at risk are not recorded. Hence, this system of passive monitoring is being practiced because Veterinary services in the country have the primary objective of providing free treatment to ailing animals. These reports collected and compiled by animal husbandry department of respective state governments are further get compiled at the national level by Department of Animal Husbandry Dairying and Fisheries (DADF), Ministry of Agriculture, Government of India, which publishes these as animal disease surveillance bulletins (Fig.1).

Although not comprehensive, these reports/ bulletins provide the following information based on clinical diagnosis.

* Animal diseases that are present in the country and its occurrence

* Provides information to respond to disease

* Meet the basic disease reporting requirements of OIE

[FIGURE 1 OMITTED]

Disease Surveillance and Indian Council of Agricultural Research

Realizing that Animal health is vital to animal production in the country, the Indian Council of Agricultural Research (ICAR) has established three institutes to look after animal disease monitoring and surveillance in the country. The institute, Project Directorate on Foot and Mouth Disease (PD-FMD) carries out epidemiological studies on Foot and Mouth Disease (FMD), while National Institute for Veterinary Epidemiology and Disease Informatics (NIVEDi) (Formerly PDADMAS) looks after the major economically important livestock diseases in the country. Exotic disease surveillance is carried out by National Institute of High Security Animal Disease (NIHSAD), Bhopal.

Project Directorate on Foot and Mouth Disease (PD-FMD)

Project Directorate on Foot and Mouth Disease, Mukteswar established by ICAR works on the epidemiological surveillance through regularly monitoring antigenicity and genomic make up of FMD vs strains responsible for disease outbreaks, to provide training in diagnosis and to develop technologies for making country free from FMD. The institute is a member of the Global FAO/ OIE Network of FMD Reference Laboratories that constitutes of ten other FMD laboratories in the world. The institute also functions as FAO Reference Centre for FMD in South Asia and SAARC Leading Diagnostic Laboratory for FMD. The institute is also a member of Global FMD Research Alliance.

National Institute for Veterinary Epidemiology and Disease Informatics (NIVEDI)

NIVEDI, Bengaluru was established in 1987 by ICAR to develop a system of disease monitoring and surveillance of economically important livestock diseases in the country, with a view to evolve strategic control measures.

In this direction, NIVEDI has made significant progress in developing short and long term disease and related databases and disease forecasting models using logistic, multiple regression and time series techniques. Accurate information about health status of a nation's animal population is critical in fight against livestock diseases and this forms basis for initiating disease control strategies through optimal utilization of meager funds, Veterinary resources and manpower.

NIVEDI has developed an innovative offline india. admas Epitrak and online NADRES epidemiology software which is a dynamic and interactive livestock disease relational database supported by Geographic Information System (GIS) (Fig. 2).

[FIGURE 2 OMITTED]

This software addresses the needs of data collection, retrieval, analysis and critical reporting of disease events as and when they occur and is useful for students and Veterinary colleges, field Veterinarians, administrators and technocrats.

The statistical model is being followed at NIVEDI include the risk factors identified are soil pattern, land use pattern, meteorological data, crop production, mineral content of soil, plants etc. The entire country has been divided into twenty zones based on major climate and plant growing period. The data on land cover viz. forest, permanent pastures, grazing lands, tree crops, food crops, wasteland, fallows, etc. The meteorological data comprise of monthly data on maximum and minimum temperature, rainfall, humidity, wind speed and direction. The data has been compiled, collated and correlated with animal diseases reported in the country by running a regression analysis. By doing so, probability of occurring of 15 major economically important livestock diseases can be predicted two months in advance. The same has been made user friendly by hosting the result at interactive website www.nadres.res.in. The input and output windows in NADRES for livestock disease forecast are shown in Fig.2.

To strengthen large scale epidemiological surveys, NIVEDI has successfully developed and released software based, highly sensitive, specific and user friendly ELISA diagnostic kits for bovine brucellosis and infectious bovine rhinotracheitis. It has also developed staining kits for diagnosis of leptospirosis. It has also created a national directory of 6.39 lakh villages for critical epidemiological sampling frames.

National Institute of High Security Animal Disease, Bhopal

NIHSAD is the country's premier facility working for handling exotic and emerging pathogens of animals by virtue of its bio-safety level IV containment laboratory and animal experi-mentation facility. Since its inception in June' 2000, NIHSAD has contributed significantly by checking entry of many animal diseases to our country. The containment laboratory, in principle, is an air tight building maintained under negative air pressure which can prevent the escape of organisms to environment through man, material, air and water.

Presently, NIHSAD undertaken research, diagnosis and surveillance of avian influenza, rabbit hemorrhagic disease, Bovine immuno-deficiency, Aujeszky's disease, porcine reproductive and respiratory syndrome, transmissible gastroenteritis, African swine fever, malignant catarrhal fever, caprine arthritis and encephalitis.

In 2001, rabbits were imported into the country for breeding program, NIHSAD was quick to diagnose that these were infected with rabbit hemorrhagic disease and their destruction during the quarantine period saved the country from ingress of the disease.

Disease Surveillance and Department of Animal Husbandry, Dairying and Fisheries (DADF)

Disease Reporting is of utmost importance. Prompt reporting of any epidemic is essential not only for undertaking immediate control measures to prevent further spread of disease, but also for formulating long term disease control strategy in the country or region. Recording the incidence of diseases is essential for estimating the economic loss, conducting risk analysis and also for obtaining disease free status of the country. In this direction, DADF has made few initiations by establishing disease diagnostic laboratories and national animal disease reporting system.

In order to provide referral diagnostic services, one Central (CDDL) and five Regional Disease Diagnostic Laboratories (RDDL) have been setup/ strengthened by DADF. The Centre for Animal Disease Research and Diagnosis (CADRAD) of IVRI, Izatnagar is working as the Central Disease Diagnostic Laboratory. The Regional Laboratories are located at Kolkata (Eastern), Pune (Western), Jallandhar (Northern), Bengaluru (Southern) and Guwahati (North-eastern). These laboratories have been set up with following objectives

* To provide referral services for diagnosing various animal diseases.

* Networking these referral laboratories with ICAR, university and state laboratories to support their programmes on disease diagnosis.

* To study the problems of emerging diseases of animals.

* To undertake surveillance against emerging and exotic infections threatening the country.

National Animal Disease Reporting System (NADRS)

The main objective of this component is to establish computerized system of animal disease reporting linking each block, district and State headquarters to Central Disease Reporting and Monitoring Unit in New Delhi by replacing the present system of disease reporting which relies on postal means of communication and entails lot of delay As a result of this initiative, it will be feasible to take timely action for control and containment of any disease outbreak, preventing economic losses to livestock owners and the country. All activities relating to development of software and installation of hardware will be carried out by NIC, making full use of infrastructure and databases already available in the states. The existing State government staff posted at block/district and state levels will be trained by NIC for proper data recording, reporting, report preparation, data analysis, etc. Under this project, networking 6,350 blocks, 615-620 districts, all state and union territories and research institutions, a total of 7032 centres will be connected.

Establishment of quarantine stations

In order to prevent the entry of exotic animal diseases into the country, DADF has established four quarantine stations at Delhi, Mumbai, Chennai and Kolkata. Additionally, construction of quarantine stations at Bengaluru and Hyderabad are proposed recently.

Epidemiology and status of important livestock diseases in India

A number of animal diseases are found in India. Among the significant ones are Foot and Mouth disease, Blue-tongue, Infectious bovine rhinotracheitis, Haemorrhagic septicemia, Black quarter, Anthrax, Tuberculosis, Paratuberculosis, Rabies, Sheep and goat pox, Equine influenza, Newcastle disease, Fowl pox, Marek's disease, Infectious bursal disease, Egg drop syndrome, Infectious bronchitis, Avian infectious anemia, Infectious pericardium, Reo-viral arthritis, Inclusion body hepatitis etc. Some of these diseases have entered the country through import of animals, birds and biologicals. India is fortunate that it has remained, as per OIE report free from as many as 40 exotic diseases of livestock. Animal disease status in India is encouraging for the facts that we were able to eradicate Rinderpest, the most dreaded livestock disease that vanished herds of cattle. But there are several other infectious diseases and noninfectious diseases, both old and new that are prevailing in the country causing huge economic loss annually.

India has remained free from Bovine Spongiform Encephalopathy (BSE), Paramyxovirus infection in horses (Hendra) and pigs (Nipah) etc. Also, old diseases re-emerge in new guises that enable them to evade current control measures. These agents might have undergone subtle genetic changes or could be recombinants with other viral or cellular genes. Immunological pressure could also be responsible for such genetic changes. These organisms may also turn out to be really new, hitherto undiscovered agents. The concern is ability of new multi-drug resistant bacteria with a pathogenic potential for human via food chain like Salmonella enterica, Campylobactor, Enterococcus spp. etc. The recent reports of zoonotic [H.sub.5][N.sub.1] Avian influenza virus crossing the species barriers and infecting humans, pigs, cats and tigers have caused alarming situation worldwide. This is especially true for pigs that have strong genetic similarity to humans.

There has been always a risk of introduction of new diseases/pathogenic organisms into a country causing serious animal health problems in terms of mortality and morbidity. Exotic pathogens, once introduced into a country, can escalate into an epidemic due to absence of vaccine or effective drugs, lack of resistance in host animals and limited resources to diagnose and restrict spread of these pathogens. Hence, there is a need to take extra precaution in import of animals infected with pathogens. As national capabilities vary from country to country, there is a vast scope for international cooperation and collaborative approaches among countries in addressing regional animal disease problems including sanitary and phyto-sanitary measures and control systems to cope with these problems. The WTO has permitted countries to exercise their sovereign rights to protect their livestock industry from such diseases.

Future perspectives

Disease monitoring and surveillance programme to be successful, availability of good diagnostics is a prerequisite. Choice of diagnostic test depends on the disease, its prevalence, number of samples to be screened, purpose of survey, etc. Currently, arrays of diagnostic tests starting from conventional tests to molecular one are being used for disease surveillance and monitoring. In future, the progress in animal disease surveillance, diagnosis and containment will largely depend on development of more accurate laboratory tests/assays. The enormous progress in biomedical science including that in biotechnology during the last two decades has made the development of novel tests possible. However, harmonization of test methodologies is necessary for uniformity in diagnosis and control measures. India is also involving in developing diagnostic technologies for exotic diseases. Steps are also being taken to disseminate technologies in advance to laboratories and facilities at various levels in the country for diagnosis and control measures. The country is in a position to handle emergencies caused by appearance of a potentially disastrous animal disease or even suspicion of existence of such a disease. Organizational structures to enact statues and provide committed to establish a comprehensive national campaign for diagnosis and control of emergency diseases similar to that developed for control of Rinderpest, Foot and Mouth disease and Avian influenza.

Further, animal disease monitoring and surveillance program suitable to Indian scenario is required as an interactive, herd/ village based national program to achieve enhanced livestock production through disease control. This will serve as a model to generate highly reliable national database by initiating activities like active monitoring through national random sample surveys, develop computerized national relational data bases and networks, analysis and GIS mapping of national epidemiological disease data, develop interactive national animal health information system for benefit of end-users, contributors, planners, decision makers and researchers. The most practical way to achieve this is through use of stringently structured national disease surveys. Surveys have two further advantages: they are quick to conduct, accurate to provide totality of disease situation and are relatively inexpensive and more precise compared to the cost of running an effective passive reporting system.

References

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Frisen, M. (1992). Evaluation of methods for statistical surveillance. Stat. Med.11: 1489-1502

Hueston, W.D. (1993). Assessment of national systems for the surveillance and monitoring of animal health. Rev. Sci. Tech. Off. Int. Epiz. 12: 1187-96.

Michael Thrusfield (2007). Veterinary Epidemiology. 3rd Edn. Blackwell Science Ltd. Oxford.UK

Myers, M.F., D.J. Rogers, J. Cox, A. Flahault and S.I. Hay (2000). Forecasting Disease Risk for Increased Epidemic Preparedness in Public Health. Adv. Parasitol. 47: 309-30.

Paskin, R. (1999). Manual on livestock disease surveillance and information systems. FAO. p.71.

Wilson, M.E. (1994). Detection, surveillance and response to emerging diseases. Annals New York Acad. Sc. 740: 336-40.

H. Rahman (1)

ICAR--National Institute of Veterinary Epidemiology and Disease Informatics (NIVEDI) Yelahanka

Bengaluru--560064 (Karnataka)

(1.) Director and Corresponding author. E-mail: hricar@gmail.com
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Author:Rahman, H.
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Article Type:Report
Geographic Code:9INDI
Date:Jul 1, 2015
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