Veterinary Epidemiology and Zoonosis

DIFFERENT SOURCES OF DATA COLLECTION

The different sources from where the data can be collected are as follows,

Government veterinary hospitals

• These organizations are responsible for investigating diseases (both infectious and non- infectious) in different species of livestock.
• Besides this, the Government has also set up various diagnostic laboratories where the specimens / samples received from the field are examined, thus helping in disease diagnosis.
• The Government Veterinary Hospitals are the major source of data collection.

Government organized farms

• There are organized farms manned by State Governments.
  • Examples in Tamil Nadu District Livestock farm (DLF), Udhagamandalam, Hosur and Orathanad, Tamil Nadu Veterinary and Animal Sciences University farms. These farms constitute the good source of data collection for retrospective studies as these data are recorded and stored routinely. These organizations can also help for prospective study as it is easy to collect information / random samples.

Central government institutes

• There are certain institutes / farms that are under direct control of ICAR / Central Government. In Tamil Nadu, Southern Regional Research Centre, Kodaikannal, Nuclear Jersey Farms, Udhagamandalam and other private farms. Besides these there are various research institutes in other States too. All these institutes are recording and storing data in relation to diseases and production events regularly. 

Private livestock farms

• Nowadays organized livestock farms are coming up in private sector also.
• The data related to milk production, type of feed used, AI practices, vaccination, number of deaths, disease occurrence, therapeutic measures followed, etc., are recorded routinely such information is very useful for knowing the patterns of diseases and its association with management / environmental factors in a particular area.

Slaughter houses

• In India, large numbers of animal (cattle, sheep, goat, pigs, etc.,) are slaughtered daily for human consumption generally apparently healthy animals are slaughtered, therefore majority of the diseases are diagnosed at meat inspection are subclinical or inapparent.
• The data related to the parasitic diseases like Taeniosis, Gastrointestinal nematodiosis and chronic diseases like TB, JD could be better obtained from these sources.
• During meat inspection it is possible to conduct auxiliary investigation of blood, sputum, lymph nodes and other tissues for specific studies for specific studies example examination of cysticercosis, echinococcosis, etc., these slaughter houses are primary sources of data for disease surveillance for conditions for which other diagnostic methods are not appropriate. Since the animals arriving at abattoir are from different places, it is possible to trace back the origin of infection.
• These sources have been used for Epidemiology surveys. Example: surveys of reasons for condemnation of sheep at Scottish abattoir.
• Abattoir investigation can also be used to indicate fault in husbandry practices.

Veterinary colleges

• All the Veterinary Colleges have Veterinary clinics where individual cases related to surgery, Gynaecology and Veterinary Medicine are treated. Thus the clinics provides useful data related to these disciplines.

Poultry farms

• There has been phenomenal growth of poultry industry in India during the last two decades.
• The data related to poultry diseases can be obtained from various broiler farms and layer farms and hatcheries.
• We can come to know the emergence of new diseases as well as reemergence of diseases if data are collected regularly.
• This in-turn helps in the understanding the disease patterns and association of various casual factors with these diseases.

Vaccine institutes

• These can provide information regarding type of vaccines produced, total doses produced and sold in a particular area / region / State.
• The vaccines for various diseases of livestock and poultry are being produced for both under government and private sectors.
• The total vaccine consumption in an area will indirectly help in knowing the disease status, and awareness among masses regarding the disease problems. 

Feed manufacturers

• Feed manufacturers (both under government and private sectors) can provide information about type of ingredients used in a mixed feed.
• We can also know the trend of ingredients used in a particular area.
• Further, if a disease is related to deficiency or excess of particular ingredient(s), increased incidence of that disease problem can be linked with that ingredient(s).
  • Example: Increased incidence of aflatoxicosis in poultry will indicate the use of contaminated ingredients like groundnut or corn in mixed feeds.

Pharmaceutical companies

• The sale records of pharmaceutical companies provide an indirect means of assessing the extent of disease in a particular area.
  • Examples: The sale of trypanocidal drugs will provide a rough estimate of the prevalence of the disease in livestock although the estimates may be inaccurate.

Private pet clinics

• Data related to health of pet animals particularly dogs, cats, lovebirds provide information regarding disease prevalence.

Government bulletins

• An international bulletin on animal diseases covering the member countries of the world is published by OIE (World Organisation for Animal Health) provides information related to disease prevalence, incidence, epidemics and pandemics in a population. Also other non governmental organizations, poultry packing plants, pet food manufacturers, zoological gardens, breed societies and Kennel clubs provide information on various diseases in animal population.

Knackers' yards

• The premises other than the slaughter houses where ill or dead animals, which are unfit for human consumption, are sent for slaughtering are referred as knacker yards.