Brucellosis in cows
One of the most common diseases in cattle is brucellosis in cows. Brucellosis can also be diagnosed in sheep, goats and pigs, but does not occur in poultry. Importantly, brucellosis in cattle can be a source of danger to humans, being transmitted in case of contact of the latter with a sick animal or through the consumption of milk and meat from infected livestock. It is not recommended to treat brucellosis in cows, as it does not bring the desired results, but worsens the symptoms and the current quarantine situation.
Brucellosis in cows
The essence of the disease
Brucellosis is also called Maltese fever (in some cases, goat fever), and this disease is provoked by the bacterium of the same name, the nature of which was first discovered in the Maltese goat and described in 1887 by a doctor in the military field, D. Bruce.
An environmentally resistant bacterium can be active for up to 2 months from the moment it enters the animal's body. In the wool of cattle, it remains tenacious for at least 4 months. When in the soil layers, brucella remains viable for up to 3.5 months.
A bacterium of the genus Brucella infects the human body through penetration through the skin and mucous membranes, through the respiratory tract. Eating contaminated foods leads to illness because the infection remains active for a long time in water and unpasteurized dairy products.
The risk group for brucellosis includes agricultural workers who are in direct contact with animals, including veterinarians, milkmaids, and farmers.
In the body of cows, brucellosis begins to develop after up to 10 or more microbes enter through microcracks on the skin and mucous membranes, into the digestive organs through feed and drinking water, into the respiratory organs from close communication with sick individuals. The pathogen of brucellosis that has entered the body through an open wound passes through the lymphatic system, subsequently entering the blood of a calf or cow.
At elevated temperatures ranging from 60 to 65 ° C, brucella dies after 15 minutes - half an hour, when the boiling point is reached, the death of the infection occurs instantly. At low temperatures, the ability of Brucella to be active can be maintained for up to 7 days in milk; in frozen meat products, it remains for 5 months. Direct sunlight and disinfecting chemical treatment have a detrimental effect on the infectious process.
Symptoms and course of infection
Brucellosis in cows can take one of 3 forms, including:
- acutely manifested, which lasts from 1 to 2 months, and its course depends on the state of the immune system of a particular animal,
- the subacute stage of the disease manifests itself within 3 months,
- in a chronic condition, the causative agent of the disease in the animal's body progresses from 3 months or more.
The pathogenesis of brucellosis most often has a chronic form of the manifestation of the disease.
When brucellosis occurs in cows, symptoms specific to the disease are observed:
- decrease in appetite and activity in cattle, decrease in productivity.
- inflammation of the joints on the front limbs (bursitis), abscesses on the hind limbs, the appearance of which can be seen in the photo,
- miscarriages frequently occurring in heifers, amounting to 50-90% per herd, more often occurring at about 7 months,
- the birth of dead or non-viable calves, a delay in the release of the placenta at calving,
- in rare cases - increased body temperature in cows,
- sick bulls have orchitis.
During the course of brucellosis, cows lose weight. Sometimes the infection leads to the concomitant appearance of endometritis in animals. If the immunity of animals is too low, accompanied by poor-quality conditions of housing and nutrition, the presence of other infections, a calf or a cow may die due to brucellosis.
Due to the fact that the infection spreads among cattle at a rapid rate, if the first symptoms appear, treatment is not carried out: to prevent more severe consequences, they resort to sanitary slaughter of animals.
Symptoms in cows in the presence of brucellosis are rather blurred, therefore, it is often not possible to diagnose the disease by only one obvious sign. To make an accurate diagnosis, laboratory tests are carried out.
Diagnostics
A veterinarian or the owner himself may suspect an ailment due to the increased incidence of miscarriages in animals. For an accurate diagnosis, they make a choice in favor of laboratory tests, which can be carried out:
- bacteriological method,
- serological method,
- allergic method.
An aborted embryo or milk or blood from a cow is taken as a material for diagnostics and research.
RA
The Wright agglutination test is the most accessible way to determine the presence of brucellosis in an animal, during which the antigen taken for the reaction is monitored.
Allergic test
To identify the causative agent of the disease, abortin is introduced into the animal's body, according to the reaction to which, after a day, sometimes after 2, but no later than 3, it is studied and a conclusion is made about the presence or absence of the disease. In the case of a positive reaction, there is a swelling at the injection site. However, when using this method, one should not forget that in the case of brucellosis transferred by a cow, the animal will continue to give a positive reaction to the drug.
Disease control scheme
Treatment of cows from infection has not yet confirmed its effectiveness, effective drugs against the disease have not been found. The most effective way in the fight against the disease of brucellosis in cows in order to maintain a healthy livestock is not the desire to cure the animals, but the stamping out of sick individuals, if there is a diagnosis.
It is possible to reduce the risk of a disease on the farm by taking preventive measures.
Vaccination
Vaccination is still the most effective way to avoid brucellosis compared to trying to treat animals. The vaccine is vaccinated on a voluntary basis every year.
Creating a supportive environment
Keeping animals must meet the necessary sanitary and hygienic requirements, which require thorough disinfection of cowsheds where there are sick individuals and the timely resettlement of sick animals. When there are cases of miscarriages in cows, healthy individuals are moved to other isolated premises so that the remains of the aborted corpses do not enter their body with water and feed.
Human precautions
Brucellosis, characteristic of cattle, is dangerous to humans.As a result of infection when eating milk or meat from a sick animal in humans, under the influence of the causative agent of the disease, the work of the heart, blood vessels, digestive system, and urinary organs is disrupted.
In order to prevent dairy and meat products acquired in epidemiologically unfavorable conditions and areas for brucellosis, a number of additional measures can and should be taken, including the following processing methods:
- subject the meat to heat treatment for at least 3-4 hours,
- bring milk to a boil and simmer for at least 10 minutes,
- make products from milk only after it has been pasteurized.
In humans, the symptoms of the disease appear no earlier than 2-3 weeks after the pathogen enters the body. Sometimes this period of manifestation of the infection is delayed up to a month. The first signs will be:
- weakness and malaise
- high temperature
- appeared pain in the temporal region,
- joint aches,
- rapid weight loss,
- the emergence of a constant desire to drink.
The course of brucellosis in humans and characteristic symptoms can be traced for up to 4 months, during which treatment is carried out. In this case, an aggravated period of infection can be observed, which passes in the form of an increase in temperature to 40 ° C, increased pain, often there is a loss of consciousness due to a disruption in the functioning of the nervous system, hallucinations are noted.
Most often, brucellosis affects men in the age group from 25 to 35 years. The male to female ratio is approximately 6: 2. Cases of the disease in children are rare: up to 2%.
Prevention helps to prevent yourself from contracting an infection, which involves the use of special clothing and shoes when working with livestock. In addition, people at risk are offered vaccinations.