The uncle suddenly changed from being diligent to being lazy, and it turned out to be because of this...

Grandpa Zhang, who has been raising cattle and sheep for his whole life, has become accustomed to the life of working from sunrise to sunset in the vast grassland with vast fields, wind blowing grass and cattle and sheep. But since when, Grandpa Zhang always feels feverish and weak, joint pain all over the body, and laziness. I can't remember the exact time, but I vaguely remember that it started after I bought a batch of lambs to feed last time. I went to the hospital in the town to see a doctor. He said that it was suspected to be lumbar disc herniation. There was no condition for surgery in the town, and conservative treatment was recommended. However, after half a year of treatment, there was no effect. After knowing this, the children who worked outside took Grandpa Zhang to the county hospital for treatment. After the doctor's consultation, he suggested to check whether there was Brucella infection? After blood culture was positive, it was screened by the tiger red plate agglutination test of the CDC, and the test tube agglutination test confirmed Brucellosis.

Recently, a beautiful female veterinarian who is a popular internet celebrity revealed that she failed to take protective measures during her daily consultations, which led to repeated Brucella infections.

1. What is brucellosis?

Brucellosis, also known as brucellosis, is a zoonotic infectious disease caused by Brucella. [1] In my country, the disease is classified as a Class B infectious disease under the Infectious Disease Prevention and Control Law, and is also an occupational disease caused by biological factors in the classification of occupational diseases. Brucella is a gram-negative bacterium and an important zoonotic pathogen. It can be divided into 12 species, of which Brucella melitensis, Brucella bovis, Brucella suis, and Brucella canis can infect humans, with Brucella melitensis being the most pathogenic. Brucella melitensis and Brucella bovis are the main prevalent species in my country. [2]

2. Transmission routes of Brucella

Brucella infects humans primarily through the following routes:

Contact transmission: direct contact with the tissues, blood, excrement or milk of sick animals, or infection through damaged skin or mucous membranes.

Digestive tract transmission: eating raw milk, dairy products or undercooked meat contaminated with Brucella.

Respiratory transmission: inhalation of contaminated aerosols.

3. Symptoms of Brucellosis

After infection with Brucella, the incubation period is generally 1-3 weeks. Common symptoms include:

Fever: The typical manifestation is "undulating fever", with the body temperature gradually rising to above 39°C, then dropping and recurring.

Excessive sweating: especially at night or when the fever subsides, the clothes may be soaked.

Joint and muscle pain: mostly migratory pain in large joints, often involving the spine, knee joints, etc.

Fatigue: Almost all patients experience it and it cannot be relieved even by rest.

Reproductive system symptoms: Men may experience orchitis and epididymitis; women may experience oophoritis and endometritis.

Other symptoms: enlarged liver, spleen and lymph nodes, headache, anorexia, weight loss, etc.

4. Treatment of suspected infection

If you suspect you have been infected with Brucella, you should go to a regular medical institution as soon as possible for diagnosis based on epidemiological history and laboratory tests. Treatment usually uses a combination of antibiotics and lasts for 6-8 weeks. If not treated in time, it may turn into a chronic infection, leading to complications in the bone and joint, cardiovascular, and nervous systems.

5. How to prevent Brucella infection?

1) The fundamental way to prevent brucellosis is to control and eliminate the spread of Brucella among livestock. Implementing an effective vaccination program for susceptible animals and regularly disinfecting breeding grounds can control the spread of brucellosis among livestock. In my country, human brucellosis vaccines are limited to immunization of high-risk groups.

2) Provide pre-operation training and guidance to high-risk groups such as those engaged in breeding, slaughtering, and fur processing, and ensure personal protection during the operation, with an emphasis on protecting the skin, cornea, and respiratory tract to prevent direct contact with pathogens.

3) Strengthen food safety, purchase fresh meat and meat products, dairy products such as beef and mutton from regular channels that have been quarantined. Develop good dietary hygiene habits, do not pursue extreme "freshness", do not eat unsterilized raw dairy products, do not eat half-cooked or raw meat products, separate raw and cooked food, avoid cross contamination, and prevent diseases from entering the body through eating.

4) In the natural environment, Brucella can survive in animal fur and soil for weeks or even months, but it is sensitive to physical and chemical factors. For example, pasteurization, sunlight exposure, and commonly used chemical disinfectants can effectively kill Brucella.

References:

[1]RoopRM 2nd, Barton IS, Hopersberger D, Martin DW. Uncovering the Hidden Credentials of Brucella Virulence. Microbiol Mol Biol Rev. 2021;85(1):e00021-19.

Published2021 Feb 10. doi:10.1128/MMBR.00021-19

[2] Tang Yuwei, Wang Yijia, Gao Jiani, Zhang Luyao, Mo Fei, Niu Shengli, Wang Yingyu. Research progress in the prevention and treatment of brucellosis[J]. Chinese Journal of Veterinary Medicine, 2024, (11): 98-106.

Written by: Wang Ya, deputy chief technician of Chongqing Jiangbei District Center for Disease Control and Prevention, Peng Jingyao, deputy chief technician of Chongqing Center for Disease Control and Prevention, and Zou Jingbo, chief technician of Zou's Science Garden