Submitting samples for lab-testing
The veterinary personnel always complain about the quality of materials collected and submitted by farmers for examination of animal diseases. Sometimes farmers will bring to the vet rotten samples of a piece of meat or a piece of the different organs such as the liver, kidneys and lungs or just the stomach content. Then this sample is contaminated with foreign germs that were not necessarily the ones that caused the disease in the first place. For a proper diagnosis of animal diseases, the type of material, time of collection, their storage and transport is of utmost importance.
Thus, for this week let’s look at a couple of materials farmers need to submit for diagnosis of animal diseases.
Fecal samples: Feces samples are often taken to determine if your animals are infested with worms (internal parasites). For sheep or goats it is easy to take a fresh dropping straight from the rectum with your fingers. Sometimes you could also pick the droppings immediately just after the animal has defecated, but be sure to take the sample that didn’t touch the ground. This is because feces touching the ground can easily be contaminated and won’t be useful. For cattle it is easy to put your glove over your hand and pick up the feces from the rectum. Then you can peel the gloves over your hand and tie it in order to store it. You can also put the feces in a glass or plastic container. This sample can then be transported to the laboratory on an ice pack or it can be kept cool in a refrigerator before being taken to the laboratory. Whichever way, it is important not to submit old or contaminated fecal samples.
Organ samples: When a farmer has opened the carcass and notices some irregularity of organs whether it is the colour, the shape or consistency, and it is not possible to take the whole carcass to the vet, it is advisable to cut fresh pieces of the major organs (preferably as soon as the animal has died). Thus, you take a piece of the kidney, the liver, the lungs, the heart or any other organ with lesions, and place them in a clean glass container that is immediately put on ice or in a refrigerator. At times it may be necessary to take pieces of the intestines and stomach, but this should be placed in a separate container than the other organs to avoid cross contamination. The containers should always be closed off tightly so as not to leak. As a precaution, it is also important to put this container in another box or container to make sure it is safe during transport.
Blood samples: Blood samples are taken quite regularly for testing of most infectious animal diseases. But this should be done by veterinary staff or by skilled farmers. The blood tubes can be bought from most veterinary drug suppliers or from veterinary services. What you do as a skilled/trained farmer is to first sterilize around the vein area where you will collect blood. Blood should be placed in the blood tubes immediately after collection and should be labelled clearly according to the date collected and identification of the individual animal. This should be placed on ice in a cool box before being transported to the laboratory or vet office. Take precaution never to shake the blood sample because the red part of the blood normally separate from the clear yellowish (serum) part and this is ideally what the laboratory looks for in order to test for infections in the serum.
Brain sample: For diseases such as rabies, the confirmatory test is done on the brain. But rabies is a dangerous disease that can be transmitted to people and thus all precautions have to be taken when handling animals that show suspicious signs of this disease. This is also true for carcasses of animals that died from suspicious signs of rabies. In fact, what we recommend is that the farmer calls in veterinary personnel in such cases. But if it is not possible to get hold of them especially in the villages far away from towns, the best idea is to submit the whole head of a suspicious animal for testing. But take caution to wear protecting clothing especially gloves and cover your nose when handling the carcass or the head. If you are not comfortable with cutting off the head or handling it, you should take the whole carcass to the vet office as soon as possible. Some farmers are so cautions that they rightfully label the container where they put the head with big bold letters “Dangerous Sample” or “Suspicious Rabies Sample” as to warn anyone to be careful around the sample.
While we are talking about rabies, farmers are warned to always take caution when any wild animals come close to the homestead without being afraid of people. You should rather shoot the animal and submit the carcass for rabies testing.
Then we have samples of external parasites such as ticks, maggots and flies that can also be taken to the laboratory/vet for identification. Mites cannot be seen with your naked eyes but with a microscope. Thus, if you suspect that your animals might be infested with mites, lice or fleas, especially when there is evidence that the animals are losing hair or seem to be itching, you can make a deep skin scraping on areas that are heavily affected and submit it in an airtight container to the laboratory.
Finally, samples should be collected and handled with all appropriate precaution. Remember that the state of samples you submit for disease investigation determines the quality or accuracy of the outcome of the test. Thus, take precaution not to submit those rotten, smelly materials, and the general rule is to keep samples cool at all times before delivery to laboratory or vet office, even during transport.