Occupational brucellosis is a brucellosis caused by infection with Brucella abortus in human occupational activities, which is a veterinary infectious-anaphylactic disease and is a national legal occupational disease, and laborers in a number of industries, such as aquaculture and food processing industries, can suffer from this disease. With the development of livestock farming in China, the incidence of occupational brucellosis has increased. According to the statistics of World Health Organization in recent years, there are nearly 1 million cases of brucellosis in the world, and the rate of new cases is increasing by 10,000-20,000 cases every year. I. Characteristics of Brucella abortus In 1886, Bruce isolated Brucella abortus from the spleen of a soldier who died of Malta fever. Brucella is a gram-positive short bacillus, its host is domestic or wild animals, it is in the secretions, feces and organs of dead animals about 4 months survival, in the food can survive for 2 months. Transmitted through the skin, mucous membranes, digestive tract, respiratory tract, etc. Humans are generally susceptible, and generally do not spread between people. People are susceptible to all kinds of Brucella, from three kinds of Brucella to human pathogenicity, to sheep species of bacteria for the strongest, pig species of bacteria often have a tendency to pus, to cattle species of bacteria to human pathogenicity is the weakest. Brucella resistance to natural environmental factors is strong, in direct sunlight can survive, but the bacterium is not strong resistance to heat and humidity, heating 60 ℃ that is killed, boiling immediately die. Resistance to disinfectants is also not strong, carbolic acid, Lysol, caustic soda solution or mercury, can be killed within the bacteria. Fresh milk of lime or formalin, can kill it. Chlorhexidine or Dumiphene, disinfectant or Neosporin, and can kill the bacteria within. Brucella can invade the human body through the intact skin, and it can also invade the body through the conjunctiva of the eyes, the mucous membranes of the digestive tract, the vagina, and the mucous membranes of the genitals. However, the pathogenicity of different strains of Brucella to the same animal or the same strain to different animals is different. The pathogenicity of Brucella, on the one hand, is related to the hyaluronidase of the bacterium itself, other enzyme systems of the bacterium, toxins and so on, but also closely related to the state of the host. Diseased animals carry pathogenic bacteria in a variety of body fluids, their vaginal secretions are particularly infectious, more bacteria in the milk, the bacteria can be months to years. Borrelia burgdorferi invades the human body after being phagocytosed, because the bacteria have pods, can resist phagocytosis, and can proliferate in the cell. Through the blood, lymphatic vessels to the local lymph nodes, to be reproduced to a certain number, break through the lymph node barrier and enter the bloodstream, repeated bacteremia. Due to the effect of endotoxin, the patient has fever, weakness and other symptoms of poisoning, after which the bacteria invade with the blood into the spleen, liver, bone marrow, etc. to parasitize within the cells, and the bacteria in the blood stream gradually disappear, and the body temperature gradually subsides. When the bacteria multiply to a certain extent in the cells, they enter the blood stream again and bacteremia occurs, and the body temperature rises again and again in the form of wave fever, and at the same time, the bacteria circulate with the blood to all organs in the body, and various complications arise. Second, the epidemic characteristics of China’s epidemic experienced the peak of the 20th century 50-70 generation, 80-90s basic control period, the epidemic rebounded in the mid-1990s. Due to various reasons sick animals elimination difficulties, the source of infection is not controlled in a timely manner, the masses of the harm of brucellosis awareness is insufficient, the current scope of the epidemic area to expand, the country spread to 24 provinces (cities and districts), and from pastoral areas to semi-agricultural and semi-pastoral areas, agricultural areas and the urban areas spread to the point of multiple dispersal of epidemic instead of large-scale outbreaks of epidemics, the number of new patients increased year by year, occupational groups, the non-occupational groups of people infected with the rate of relative increase, the elderly and children have also increased. There is also an increase in the incidence of old age and children. Most cases of brucellosis should be categorized as occupational diseases. The risk of occupational exposure to brucellosis is about 25%, and the main modes of exposure are: animal consignments, driving or catching animals, birth control and hemostasis, skinning or mastectomy, flushing or disinfection process, etc. There are many industries and types of work involved, and the incidence rate of infection in this group of people is significantly higher than that of people engaged in other occupations, vaccine producers, and laboratory workers, such as animal husbandry workers, veterinarians, slaughterers, meat and fur processors, and laboratory workers. People engaged in other occupations, vaccine production personnel and disease control personnel can also be infected or morbidity. Transmission route: Brucellosis can be infected through skin mucosa, digestive tract and respiratory tract, and occupational brucellosis is transmitted through skin mucosa and respiratory tract. The former is common with the contact of diseased animals, animal husbandry personnel, veterinarians, feeding, milking, livestock processing, slaughter and other occupational groups; the latter for the laboratory and the production of Brucella vaccine staff of the infection pathway. Close contacts can also be infected from these two ways at the same time. Third, the clinical manifestations of Brucella can violate the system, often involving the liver, spleen, bone marrow, lymph nodes, but also can involve the bone, joints, blood vessels, nerves, endocrine and reproductive systems, etc., the clinical manifestations of the complexity and variability of the common prolonged fever, hyperhidrosis, joint pain, liver and spleen enlargement, but the lack of specificity. It is easy to be misdiagnosed. Bone joints are involved in about 40% of the cases, most often involving hip joints and knee joints, followed by sacroiliac joints, shoulder joints, ankle joints, small joints of the spine and bursitis, etc. Clinical manifestations are myalgia, arthralgia and arthritis. Asymmetric, some joints are red, swollen, indurated and dyskinesia; muscle strength of both lower limbs is decreased, and walking is difficult. Lung involvement about 10%, mainly manifested as cough, sputum and dyspnea; chest X-ray showed pulmonary nodules, lobular pneumonia, paratracheal lymph node enlargement and pleural exudation. Neurological complications are about 1.7%-10%, with peripheral nerve damage being common and central nervous system damage being rare. Sciatica is the most common peripheral nerve damage; meningitis, polyneuritis and myelitis are the most common central nervous system injuries. Damage to the auditory nerve, cerebrospinal meningitis, cerebellitis, and cerebrovascular endocarditis are rare. Gastrointestinal involvement may manifest as loss of appetite, abdominal pain, and diarrhea; occasionally there are mild blood abnormalities, such as anemia, leukopenia, thrombocytopenia and thrombocytopenic purpura, and bleeding. Some patients manifest only a single system or a single symptom, such as orchitis, meningitis, optic neuritis, acute cholecystitis, cervical lymph node enlargement, lower limb paralysis. Transient proteinuria, hematuria, urinary frequency, urinary urgency and urinary pain in the kidney and urinary system are misdiagnosed as glomerulonephritis. There has been a marked increase in atypical cases in recent years, which are characterized by a short course of the disease, mild symptoms, and a marked decrease in lymph nodes, hepatosplenomegaly, and osteoarticular deformity and ankylosis, which are replaced by prolonged low-grade fever, malaise, arthralgia, polyneuralgia, and polyneuritis. In some cases, the diagnosis is delayed by the manifestation of undulating fever pattern, unremarkable phenomenon of excessive sweating, joint pain, and late appearance of neurologic and genitourinary symptoms. Brucellosis is an infectious disease with multi-system involvement. Routine laboratory tests, except for elevated blood sedimentation and C-reactive protein, have no obvious abnormality, and it is easy to be misdiagnosed as viral infection, tuberculosis, arthritis, and vasculitis, etc. In particular, atypical cases are increasing. In particular, the increase of atypical cases may be related to the long time of misdiagnosis, the use of various antibiotics and other informal treatment. Once the diagnosis of occupational brucellosis is established, treatment should be given immediately. The principle is to combine the drugs, the dose is sufficient, the course of treatment is enough, generally combine two antimicrobial agents, commonly used cephalosporins combined with quinolones, three courses of treatment, each course of treatment time varies, the interval between the two courses of treatment for about 10 days, for the small number of acute infections or serious conditions, can be added with rifampicin, and appropriately prolong the period of treatment. Immunomodulators are also given to enhance cellular immune function and reduce or avoid intracellular parasitism of Brucella.