Introduction
Brucellosis is one of the most common zoonotic diseases globally (Dean,
Schelling, & Zinsstag, 2014). More than 500,000 new human cases of
brucellosis are reported annually (Deng, Liu, Duan, & Peng, 2019), and
millions of livestock are either infected or at risk (Pappas, 2010). It
is a significant public health problem and causes serious harm to the
development of the livestock industry and human health (Saddique et al.,
2019). Brucella is most commonly transmitted by indirect or
direct contact with infected livestock and the consumption of
contaminated raw milk or their products (Kairu-Wanyoike et al., 2019).
At present, 12 species have been identified in Genus Brucella ,
including six classical species and six newly detected biovars. Among
them, Brucella melitensis is the most severe both in
infectiousness and pathogenicity to humans (Eschenbrenner et al., 2002).
Fever, fatigue, sweating, and muscle and joint pain are the main
manifestations in the acute stage of human brucellosis (W. Jiang et al.,
2019). The pathogen can invade various systems of the human body and
seriously affect the quality of life (Venyo, 2015).
Brucella spp. are highly infectious because the infectious dose
by an aerosol is only 10 to 100 organisms (D. L. Sewell, 2006), and it
has been considered the most important laboratory-acquired bacterial
infection (Al Dahouk & Nöckler, 2011). Aerosol transmission generated
accidentally or during microbiologic techniques from contaminated
materials are the proposed routes of transmission (Bossi et al., 2004;
Lowe et al., 2015). As aerosolization is the primary mechanism of
transmission in this setting (Memish & Mah, 2001), it is recommended
that the organism be handled according to level 3 biosafety precautions
(Fiori, Mastrandrea, Rappelli, & Cappuccinelli, 2000). These guidelines
can be challenging to follow, particularly in regions with a low
incidence of brucellosis. All the Brucella spp. have been
implicated in laboratory-associated infections, and they may account for
up to 2% of all laboratory-associated infections (Robichaud, Libman,
Behr, & Rubin, 2004). In China, several cases of brucellosis are
reported annually, but no national surveillance system specifically
identifies laboratory-acquired cases. Therefore, the epidemiological
profile of brucellosis resulting from laboratory transmission and S2
vaccine outbreak events of brucellosis in China remains unknown. The
purpose of this study is to summarize laboratory-acquired infection and
S2 vaccine outbreak events of brucellosis in China so that effective
countermeasures for the prevention of laboratory-acquired infections and
the promotion of public health safety can be designed.