Brucellosis is recognized globally as one of the most common zoonotic diseases and accounts for more than 500,000 human cases every year.1 Humans are infected mainly through contact with infected animals or by consumption of contaminated dairy products.2 Brucellosis remains a serious public health issue in developing countries, including China. At present, brucellosis is endemic in 30 provinces or autonomous regions in China; the incidence increased substantially from 1.41 per 100,000 population in 2005 to 2.7 per 100,000 population in 2009.3 The major epidemic species in China is Brucella melitensis.4 With an incidence of 0.01 per 100,000 population, Jiangsu Province is one of the lowest incidence areas of brucellosis in eastern China.3
On August 8, 2013, clinicians at the First Affiliated Hospital of Nanjing Medical University in Nanjing, Jiangsu Province, reported to Jiangsu Provincial Center for Disease Control and Prevention that four patients from the same family had contracted brucellosis. An investigation was initiated to determine the extent of spread, source of infection, and possible mechanisms of pathogen introduction into this area.
The four family members are residents of Shuyang County, located in the north of Jiangsu (Figure 1), where no cases of brucellosis have previously been reported. Active case finding was conducted by searching local hospital records and outpatient clinical files, and by interviewing brucellosis cases, family members, and neighbors dwelling in the same villages. Information about demography, clinical symptoms, possession of or contact with animals, participation in common meals, consumption of dairy products, or traveling to brucellosis-endemic areas was collected at the same time. The study was approved by the Ethics Committee of the Jiangsu Center for Disease Control and Prevention (CDC). Informed consent was voluntarily obtained from all participants.
We defined confirmed cases as any resident displaying positive by serum agglutination test (SAT) (Brucella agglutination titer greater than or equal to 1:160) or blood culture and at least one of the following symptoms: fever, night sweats, arthralgia, malaise, and headache. In total, six brucellosis cases from two families were identified in Shuyang County from January 1 to August 15, 2013. Five cases came from one extended family referred to as “family A” (Table 1). The remaining cases came from a family referred to as “family B.” Details of the six patients at presentation were described below.
Epidemiological and clinical features and laboratory results of 10 cases with brucellosis
|Filiation||Index case||Father||Cousin||Mother-in-law||Wife||Brother||Sister-in-law||Index case||Father||Mother|
|Pain||Arthralgia||shoulder and back pain||No||Body ache||No||/||/||No||/||/|
|PLT (125–350 × 103/μL)||184||176||180||248||135||/||/||130||/||/|
|ESR (0–15 mm/H)||8||70||31||/||25||/||/||6||/||/|
|ALT (0–50 U/L)||16.8||29.8||68||14.7||24.8||/||/||126.4||/||/|
|AST (0–50 U/L)||19.6||20.2||64||17.1||41.2||/||/||65.0||/||/|
|TBIL (5.1–19 μmol/L)||19.5||15.6||12.0||3.4||9||/||/||11.4||/||/|
|Isolation||Brucella melitensis||B. melitensis||B. melitensis||Negative||B. melitensis||/||/||B. melitensis||/||/|
F = female; M = male; n.d. = not done; SAT = serum agglutination test; / = NA; WBC = white blood cell; PLT = platelets; ESR = erythrocyte sedimentation rate; ALT = alanine aminotransferase; AST = aspartate aminotransferase; TBIL = total bilirubin.
We thank Ian J. Miller of the University of Wisconsin, Madison for his help with editing, and John Klena from the US Centers for Disease Control and Prevention for modifying our manuscript.
Pappas G, Papadimitriou P, Akritidis N, Christou L, Tsianos EV, 2006. The new global map of human brucellosis. Lancet Infect Dis 6: 91–99.
Chen JD, Ke CW, Deng X, Jiang S, Liang W, Ke BX, Li B, Tan H, Liu M, 2013. Brucellosis in Guangdong Province, People's Republic of China, 2005–2010. Emerg Infect Dis 19: 817–818.
Man T, Wang D, Cui B, Wang Y, Ding F, Li TF, 2009. Analysis on surveillance data of brucellosis in China, 2009 [in Chinese]. Dis Surveill 25: 944–946.
Mukherjee F, Jain J, Patel V, Nair M, 2007. Multiple genus-specific markers in PCR assays improve the specificity and sensitivity of diagnosis of brucellosis in field animals. J Med Microbiol 56: 1309–1316.
Bricker BJ, Halling SM, 1994. Differentiation of Brucella abortus bv. 1, 2, and 4, Brucella melitensis, Brucella ovis, and Brucella suis bv. 1 by PCR. J Clin Microbiol 32: 2660–2666.
Le Flèche P, Jacques I, Grayon M, Al Dahouk S, Bouchon P, Denoeud F, Nöckler K, Neubauer H, Guilloteau LA, Vergnaud G, 2006. Evaluation and selection of tandem repeat loci for a Brucella MLVA typing assay. BMC Microbiol 6: 9.
Whatmore AM, Shankster SJ, Perrett LL, Murphy TJ, Brew SD, Thirlwall RE, Cutler SJ, MacMillan AP, 2006. Identification and characterization of variable-number tandem-repeat markers for typing of Brucella spp. J Clin Microbiol 44: 1982–1993.
Jiang H, Fan M, Chen J, Mi J, Yu R, Zhao H, Piao D, Ke C, Deng X, Tian G, Cui B, 2011. MLVA genotyping of Chinese human Brucella melitensis biovar 1, 2 and 3 isolates. BMC Microbiol 11: 256.
Kılıç S, Ivanov IN, Durmaz R, Bayraktar MR, Ayaslioglu E, Uyanik MH, Aliskan H, Yasar E, Bayramoglu G, Arslantürk A, Vergnaud G, Kantardjiev TV, 2011. Multiple-locus variable-number tandem-repeat analysis genotyping of human Brucella isolates from Turkey. J Clin Microbiol 49: 3276–3283.