Written by Dr. Samuel Akpan
A disease outbreak is the sudden onset or increase of incidence of a particular disease in a given population at a particular time or period. For example, in a poultry farm of 1000 birds, a farmer may observe that on a certain day, about 20-30 birds are coughing, stooling blood or staying off feed. A similar occurrence may be observed in 50-60 birds on the second day, and progressively higher in subsequent days. Such occurrence is an indication of a disease outbreak.
Livestock diseases often arise from non-infectious or infectious causes. Non-infectious causes are majorly nutritional, environmental or hereditary; while infectious causes span across bacteria, viruses, fungi, and parasites. This is the category majorly responsible for disease outbreaks on a farm.
A farmer’s adequate response to such infectious animal disease outbreaks is of paramount importance to ensuring animal health and by extension – One Health. This is because healthy animals result to a healthy environment, safe food and healthy humans, and the need to protect humans from zoonotic diseases. Also, many people erroneously believe that it is the sole responsibility of the veterinarians to manage and prevent animal health infections on the farm. However, it is pertinent that veterinarians work together with other livestock farm management staff including the farm owners, nutritionists, feeders, cleaners etc for proper farm disease prevention and control.
For example, due to pedigree or other growth/production considerations, farmers/producers commit the error of introducing healthy-looking but infected animal/bird(s) into an already healthy herd/flock. The infected animal/bird then serves as source of infection. Outbreaks may also occur during vaccine failures, when a vaccine is administered on apparently healthy but sick animals/birds. Together with stress and other factors, this may compromise herd/flock immunity, and the viral/bacterial component of the vaccine becomes responsible for a rapid disease outbreak. In many cases, mortalities ensues outright before any morbidity trend or clinical signs can be observed.
As a farmer or farm personnel, your response or reaction to a disease outbreak can eradicate or slow down morbidity or mortality in your herd/flock, and reduce your losses. The first way to respond is by immediate removal of the dead animals/birds, and isolation of the sick ones for further observation or treatment. You should also respond in the following ways:
- Resist the temptation of selling any animal/bird to another farm for the purpose of production. You may be spreading the disease to another farm/location.
- Farm workers should wear adequate protective clothing while removing the dead carcasses, or moving the sick animals. This is in order to prevent animal-human transmission, in event of a zoonotic disease.
- The area or pen where the mortality/morbidity is recorded should be thoroughly disinfected, after the remaining healthy animals have been moved into another space/pen.
- Within 24 hours, endeavor to report the incidence to your local animal health authority or where possible, a veterinarian. They will take samples to determine the cause or nature of the disease, as well as treatment or stamping out measures. It is also important for surveillance purposes and emergency response preparation in case outbreaks occur in other farms in your location/area.
When only widespread clinical signs or conditions are seen, you should:
- Inspect the feedstuff, forage, or concentrate to determine if it is the bright one, wet, mouldy, or has other harmful material. If you suspect the feedstuff, change it immediately.
- Inspect the water source again
- Manage the ambient temperature to reduce stress.
- Remove any water troughs shared by the birds/animals (a precautionary measure to avoid spread, in case secondary infectious agents are involved).
- In the case of birds, manage the light intensity.
These can help to reverse the situation or slow down effects of an outbreak, until you are able to receive professional help and further instructions from the animal health or veterinary authorities.