Prevention and Control Methods and Countermeasures for Anthrax in Sheep
Recently, a large number of meat sheep died in Heilongjiang, and testing by the relevant departments found that the cause of death was an outbreak of acute anthrax. Anthrax is an acute febrile epidemic infectious disease caused by Bacillus anthracis. Anthrax is extremely contagious and, in severe cases, can even be transmitted to humans. Many friends do not know how to identify anthrax, nor do they know how to prevent and treat it. Below, the editor will give a brief introduction for everyone.
1. Disease Characteristics
In the natural environment of invasion, anthrax most easily invades various herbivorous animals, most easily infecting sheep, cattle, horses, and others, while the incidence rate in pigs is relatively low. It also has a certain invasive capacity for people who frequently come into contact with these animals. In an outbreak of sheep anthrax, sick sheep are the most important source of infection. The bacteria can spread through saliva, urine, and a series of other factors, and are also excreted from the body along with feces, spreading through various natural factors. After forming spores, it may turn the breeding area into an epidemic focus. The main cause of disease in sheep is eating water and feed containing the bacteria, resulting in infection through the digestive tract.
2. Disease Symptoms
The onset of anthrax is acute and sudden. After becoming ill, the sick sheep will suddenly become comatose, lie on the ground unable to rise, and be unable to stand normally, and the whole body will experience spasms. Body temperature will also rapidly increase to above 40 degrees, the mucous membranes will become cyanotic, breathing will be loud, and respiration will be rapid and may even become impossible. Death occurs within a few hours, and before death the natural orifices will begin to bleed. In cases with slower symptoms, there will initially be brief excitement and restlessness, running around and moving erratically, and discomfort whether sitting or lying down. After this stage, the animal will begin to show poor spirits, refuse to eat, have an accelerated heartbeat, and pass feces mixed with blood.
3. Diagnostic Methods
Wearing protective antibacterial equipment, collect a small amount of blood from the ear blood vessels of a dying or dead sick sheep for capsular smear staining, and examine it with a microscope. If many bacteria are found on the capsule, either single or in chains, with junctions like bamboo nodes, then it is undoubtedly anthrax. This bacterium is a Gram-positive large bacillus and is the main pathogen of anthrax. When collecting blood, special care must be taken not to let the blood spill on the ground. You can also take blood from a dead sheep, add it to physiological saline, boil for half an hour, cool it, filter it with filter paper, then add it to a thin glass tube, draw it up with a capillary pipette, and slowly drip it onto the upper layer of serum to observe the result. If a white precipitation ring is found, then it is anthrax.
4. Prevention Methods
Because sheep die within a few hours after contracting anthrax, there is currently no effective treatment method, so prevention in advance can only be the main approach. After discovering sick sheep, they must be isolated immediately. Sheep with similar symptoms must also be promptly moved out and raised separately, and the situation must be reported immediately to the relevant departments. For sheep that died of the disease, all materials contacted by the carcass, such as manure, urine, and soil, must be immediately deeply buried or completely burned, far away from normal sheep sheds. The sheep shed must be disinfected immediately, using hot alkaline water and bleaching powder for comprehensive disinfection at least three times, with an interval of at most one hour. If some sheep have already become ill, the remaining sheep must immediately be given anti-anthrax serum, with the dosage determined according to the instructions. The flock must be regularly injected with avirulent anthrax spore vaccine for prevention, but goats need to be injected with anthrax vaccine No. 2. Lambs under one year old must not be injected with any drugs.
The source of anthrax should be confirmed in a timely manner. If it is feed infection, the feed should be replaced promptly, and all remaining feed should be completely removed. If it is pasture infection, grazing should be stopped immediately and the infected area avoided. When handling anthrax, special attention must be paid, and people must wear antibacterial protective clothing to prevent transmission to humans. Anthrax is a very severe infectious disease. When it is discovered, corresponding preparations must be made immediately, otherwise it can cause the entire flock to become infected and die immediately. This causes incalculable economic losses.