Lab technique

ROLE OF LABORATORY TESTS IN ANIMAL HEALTH

March 14, 2023

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ROLE OF LABORATORY TESTS IN ANIMAL HEALTH

Diagnostics are essential tools to ensure the health of domestic and wild animals for both endemic and emerging diseases. They allow animal health professionals to understand and manage the general health status of domestic animals, and they are essential for animal health authorities during the emergence of disease and in the eradication or control of notifiable animal diseases. They are also important tools to support public health initiatives in the case of zoonotic disease control and can be used in the fight against antimicrobial resistance. Diagnostic assays can play an important role in the testing of new and authorised biologics.

Laboratory tests are a very important and useful tool for assisting us in the diagnosis of many health problems in our pets. They help veterinarians diagnose diseases which may not be clinically evident, confirm diseases which may be suspected upon clinical examination, and help us to monitor disease progression.

Animal disease diagnosis is considered to be an important issue in the country due to its implication for animal and poultry wealth, which is one of the most important sources of income and means of livelihood of the farming community. India lies in a biological hot spot and shares international boundary which adds to the risk of exotic diseases that are considered the most important problem facing this wealth. It is also necessary to accelerate the evaluation of the level of animal disease diagnostic laboratories in order to ensure the safety and protection of human food as one of the top priorities. The role of laboratories in protection of animal and poultry industry from endemic and exotic diseases, quick, efϐicient and accurate diagnosis of the causative agents and advocating and administering control measures cannot be denied.

As an example, FIV is a viral disease in cats which can remain subclinical for many years. The only reliable way of diagnosing this disease is by looking for antibodies in a blood sample. From clinical symptoms and from the patient history provided by you, we may be able to diagnose many diseases with a fair degree of certainty but will often need to confirm this disease with blood and urine testing. Monitoring disease progression and medical management of disease is often done with regular blood & urine testing also.

Blood and urine testing is considered part of the “minimum data base” (the minimum amount of information required to make an accurate diagnosis) for diagnosing many diseases. It is also essential in the diagnosis of diseases or medical conditions which are diagnosed by the exclusion of all other possible conditions, for example some behavioural problems.

Blood and urine testing are probably the most frequent tests we recommend in an initial investigation as they generally provide the most amount of information and are fairly simple to obtain. We will recommend these tests when a diagnosis is not clinically evident, to confirm a diagnosis or to make sure your pet has no underlying health problems, for example before your pet undergoes an anaesthetic.

It is evident that prevention is better than cure. The approach should be directed towards the prevention of diseases through better management practices as well as through vaccination programme. Even after possible control measures, the animals fall ill due to one reason or the other. In earlier day of veterinary practices, no doubt, much of the diagnosis was based on the history of the disease told by the owner which many a times lead to incorrect diagnosis, thereby delaying the treatment of the animal. This makes the treatment part costly and sometimes ineffective as well. The owner/farmer comes under heavy economic loss due to rising cost of treatment and the decreased productivity of the animal. Under such circumstances, the early and cost effective treatment becomes the need of the hour to prevent further production losses. To attain this objective the routine laboratory tests make a valuable contribution in early diagnosis of the disease condition, so that the problem can be dealt with on scientific lines. Therefore, in modern veterinary practice the laboratory tests are having a key position so as to ensure better prognosis as well as minimizing the treatment cost. These tests gain further significance since these help in prevention, control, containment and eradication besides deciding the line of appropriate treatment. The laboratory test play vital role in making early and correct diagnosis which cautions about introduction of a new disease among animals paving a way for its early containment that can save valuable resources of a nation in terms of money and man power. For laboratory tests, different materials are taken from the animal and are subjected to a series of techniques in the laboratory to get information about the health/disease status of the animal. The collection process and the importance of some useful materials for undertaking/laboratory tests is given here.

Blood: It is the most important body fluid that performs different kinds of functions in the body. For taking blood, a small amount of spirit is applied at the site of a superficial vein. With the help of a sharp hypodermic needle, the blood is collected in a clean glass vial containing a very small amount of an anticoagulant. An anticoagulant is a substance which prevents clotting blood and EDTA is used @ 1 mg/ml of blood. After collection, blood vial should be tightly closed, gently rotated between the palms, however, should not be vigorously shaken to avoid unnecessary damage to the blood sample. The sample should be taken to the nearest veterinary diagnostic laboratory or to the GADVASU Hospital as soon as possible. But, if its immediate transportation is not ensured, then it can be kept for one day in refrigerator (4°-8°C). About 2-3 ml of blood is sufficient for haematological and prozoal examination. The haematology, in general tells us about anaemia, dehydration and the disease status of the animal. The prozoal examination helps to diagnose some common diseases like trypanosomiasis, babesiosis, anaplasmosis and theleiriasis etc.

The serum (fluid portion of the blood) is obtained by collecting the blood without anticoagulant. This is analysed for enzymes and other constituents/toxic substances to monitor the function of different organs/systems of the animal. In additional to this, it also constitutes an important material for the diagnosis of diseases like brucellosis, haemorrhagic saepticaemia (Gal Ghotu), foot and mouth disease (Muh Khur) etc. The help of the Veterinary Doctor of your area may be taken to collect the blood sample.

Urine: The blood is filtered through kidneys. The extra substances and water which is not required by the body excreted out in the form of urine. So the composition of urine reflects the functioning of urinary system from kidney to urethra and of other systems as well. About 100 ml of urine should be collected in a clean dry and colourless bottle and should be transported in a ice pack. The examination of urine helps in the diagnosis of albuminuria, ketouria, jaundice and other infectious conditions of urinary tract.

Stool (Feaces): The stool or faecal examination of the animal is performed to detect the presence of particular parasite/ova in the animal body. This help in the specific treatment of the animal. The stool sample should preferably be collected in the morning in a bottle or a match box or in polythene bag. If the stool sample is to be collected from the floor then the sample from the mid internal portion should be taken out with the help of a small stick. The sample should reach the laboratory as early as possible.

Milk: Examination of milk helps to defect the cause and cases of mastitis. For this, hands should be washed thoroughly with soap and water for collection of milk. Remove any dirt from the udder and then wash it with a dilute solution of disinfectant (potassium permanganate 1:1000 water). Dry the teats with the help of clean muslin cloth and apply some disinfectant at the end of teats. For culture and sensitivity the milk sample should be collected in sterile test tubes after discarding first, two or three streams. It should be sent for examination as soon as possible in a container having ice. Culture and sensitivity test (CST):

This test consists of two processes: 1. Culturing of the organisms present in blood/milk/urine/stool on some particular media, to identity the causative agents. Its second part consists of selecting medicine which is most effective against these causative agents. In this way the treatment becomes accurate, rational and also economical. The sample should be collected strictly according to instructions of the Veterinarian.

Radiography: (X-ray) and ultrasound scanning: Radiography is often used to diagnosis and confirm fractures of bone and to locate other lesions of the musculoskeletal system, the cases of foreign body ingestion and diseases of feet. Ultrasound scanning is used to diagnose the conditions like urolithiasis, gallbladder stones, tumors, intestinal

obstructions and pregnancy diagnosis etc.

Biopsy: For this a small portion of the affected part is surgically removed or taken with instruments from the living animal and is examined under micro-scope after the portion has been subjected to a series of different techniques. This procedure is mostly used to diagnose different kinds of tumours or growths in and outside the body.

Post-mortem: It is the examination of the body and organs after death. It can be conducted on all animals and birds. The body parts and organs are examined for changes in gross appearance, or microscopically for changes in tissues. Postmortem examination should invariably be got done. Its results can help save lives of other animals and birds.

It is hereby advised that one should make efforts to bring their animals or samples early for diagnosis. This can give better dividends in terms of saving lives of animals and to prevent economic loses.