Table 1.

 Clinically significant bacterial zoonoses

Pathogen	Comments
Anaplasma phagocytophilum	Human granulocytic anaplasmosis has been increasing and expanding its incidence: recently recognized in Canada; an ongoing outbreak is reported from China [7]. Exceeding 1000 cases annually in the USA, as of 2008 [8]
Bacillus anthracis	The, fortunately, only case of emergence caused by deliberate release
Bartonella sp.	There are 22 000 new annual cases of cat scratch disease reported annually in the USA [9]; Bartonellahenselae and Bartonella clarridgeiae implicated. B. henselae, Bartonella elizabethae and Bartonella grahamii are causes of zoonotic endocarditis [10]. Bartonella vinsonii and Bartonella alsatica are also zoonotic. The spectrum of agents is likely to expand as novel species are recognized
Borrelia sp.	Borrelia burgdorferi ecology has resulted in the re‐emergence of Lyme disease in the USA: 28 921 confirmed cases were reported in 2008 [8]. All other borreliae are zoonotic, excluding Borrelia recurrentis
Brucella sp.	Brucella melitensis, Brucella abortus, Brucella canis, Brucella suis, Brucella pinnipedialis and Brucella ceti cause human disease. It is estimated that there are more than 500 000 new cases annually [11], excluding chronic cases. Repeated outbreaks in former Communist republics of Central Asia, and emergence in Balkan states, previously brucellosis‐free. Experimental documentation of Brucella microti zoonotic potential. Unknown zoonotic origin of novel non‐characterized strains [12]
Burkholderia mallei and Burkholderia pseudomallei	The former causes glanders, a typical but very rare zoonosis. Melioidosis annual incidence in northeast Thailand exceeds 12  cases/105 [13], with significant mortality. Historical zoonotic outbreak in a Paris zoo in 1973 [14]
Campylobacter sp.	Campylobacter jejuni is possibly the commonest zoonotic foodborne pathogen worldwide; almost 200 000 cases are recorded anually in the European Union (EU) [15]. Campylobacter fetus, Campylobacter coli, Campylobacter hyointestinalis, Campylobacter lari and Campylobacter upsaliensis are also zoonotic
Capnocytophaga canimorsus and Capnocytophaga cynodegmi	Dog‐bite related; splenectomy and alcoholism may predispose—a recent review in The Netherlands detected more than ten annual cases [16]
Chlamydophyla psittaci	There are 10–20 cases of psittacosis documented annually by the CDC [8]. Micro‐outbreaks are irregularly reported, predominantly from Australia, but also in Japan and The Netherlands
Clostridium sp.	Can be considered to be zoonotic foodborne diseases, although the zoonotic aspect is of limited significance [17]. Clostridium botulinum infection is not typically zoonotic, even when foodborne
Corynebacterium ulcerans	Corynebacterium ulcerans is increasingly recognized as an important factor in possible diphtheria re‐emergence [18]. Other non‐diphtheria species are of limited significance
Coxiella burnetii	Massively under‐reported worldwide, despite being acknowledged as an important cause of endocarditis. There were 106 acute cases in the USA in 2008 [8]. A recent Netherlands outbreak highlighted limited surveillance issues [19], and increased the number of reported cases in the EU in 2008 to 1594. Germany, Spain, Slovenia and the UK report most other cases [15]
Ehrlichia chaffeensis and Ehrlichia ewingi	The number of human monocytotropic ehrlichiosis cases reported in the USA is continuously increasing, exceeding 900 in 2008 [8]. Human ewingii ehrlichiosis is more rare
Escherichia coli	The O157:H7 strain is consistently causing zoonotic foodborne and waterborne outbreaks [20]. Secondary effect through risk of haemolytic–uraemic syndrome development
Francisella tularensis	The tularaemia outbreak in Kosovo underlined the relationship of zoonoses with socio‐economic and political factors [21]. Outbreaks of varying intensity have also been reported in Bulgaria, Georgia, and Turkey. Disease is rare (or understudied) in the EU; approximately 100 cases are recorded annually in the USA [8]
Helicobacter sp.	A speculative zoonotic potential for non‐Helicobacter pylori Helicobacter sp. exists [22], although the role of animals in transmission of these species to humans has not been proven adequately
Leptospira sp.	The annual burden of leptospirosis is largely underestimated (inadequate surveillance; majority of cases mild or subclinical) [23]. The annual number of cases may exceed 500 000, the majority arising from India and Southeast Asia
Listeria sp.	Increasingly recognized in Europe—1300–1500 EU cases annually [15]; declining incidence in the USA that has stabilized below 0.3 cases/105 [8]. A recent Canadian outbreak exhibited significant mortality [24]
Mycobacterium sp.	Mycobacterium bovis still causes a small percentage of human tuberculosis by transmission from cattle or possums, as also observed less often with Mycobacterium caprae. Also included are Mycobacterium marinum, Mycobacterium microti, Mycobacterium avium, Mycobacteriumgenavense, possibly Mycobacterium malmoense, and Mycobacteriumfarcinogenes. There has been a long debate on the potential aetiological relationship between M. avium paratuberculosis and Crohn’s disease in humans [25]. The mycobacterial life cycle leading to Mycobacterium ulcerans human infection and Buruli ulcer, and the significance of animal reservoirs in this cycle, have not yet been clarified adequately enough for it to be classified as zoonotic or non‐zoonotic
Orientia tsutsugamushi	The burden of annual scrub typhus cases in Southeast Asia and the Southwest Pacific approaches 1 000 000 [26]
Pasteurella sp.	Pasteurellosis remains a relatively rare human infection,; it has been better understood and studied in animal disease
Rickettsia sp.	The numbers of cases of Rocky Mountain spotted fever reported annually were increasing in the USA in the early 2000s, exceeding 1000 cases in 2002. For rickettsial pox, the mild nature of human disease may contribute to underdiagnosis and under‐reporting. The same is partly true for Mediterranean spotted fever, which can, however, be considered to be endemic in the region [27], and for African tick bite fever [26]. The endemicity of North Asian tick typhus remains understudied, whereas Queensland tick typhus and Japanese spotted fever can be considered to be both rare and localized. Murine typhus is generally sporadic and under‐reported. Epidemic typhus shows an expanding animal reservoir frame (including flying squirrels in the USA), exhibits the secondary effect of BrillZinsser disease, and, more importantly, exhibits significant outbreak dynamics, which are nowhere better evaluated than in the notorious Burundi outbreak [28]
Salmonella sp.	Excluding Salmonella typhi, 51 030 cases of salmonellosis were recorded by the CDC in 2008 [8], the majority of which were caused by Salmonella enteritidis and Salmonella typhimurium; S. enteritidis was responsible for the 2008 US outbreak, with more than 1000 cases, more than 250 hospitalizations, and at least one fatality. More than 100 000 cases are recorded in the EU annually [15]
Shigella sp.	Shigellosis remains a major health issue worldwide, with tens of millions of cases and tens of thousands of deaths annually being attributed to it, particularly in young children, according to the WHO. Twenty‐two thousand six hundred and twenty‐five cases of shigellosis were reported by the CDC in 2008 [8]. EU data are inadequate on the subject
Staphylococcus aureus	The zoonotic significance of S. aureus is predominantly related to the role that animal reservoirs (such as pigs) play in expanding and sustaining the presence of methicillin‐resistant S. aureus in the community, as demonstrated in The Netherlands [29]
Streptococcus sp.	Streptococcus suis is increasingly recognized in East Asia—a Chinese outbreak in 2004 resulted in 38/204 fatalities [30]. An Streptococcus equi outbreak associated with goat cheese occurred in Finland in 2003 [31]. The frequency of Streptococcuscanis infection may be underestimated. Streptococcus acidominimus is also zoonotic. The zoonotic significance of Streptococcus bovis is of minor importance concerning its primary manifestations in human disease
Vibrio sp.	Including Vibrio parahaemolyticus and Vibrio vulnificus, characteristically identified in the USA in the aftermath of Hurricane Katrina [32], but excluding Vibrio cholerae. Also with zoonotic potential are Vibrio alginolyticus, Vibrio fluvialis, Vibrio furnissii, Grimontia hollisae, and Vibrio mimicus [33]
Yersinia sp.	Plague remains, for both historical and purely scientific reasons, a major bacterial threat [34]; the WHO data for 2003 recorded more than 2000 cases, with mortality reaching 8.5%; the vast majority of cases were in Africa. Isolated cases are reported annually in the USA. Yersiniosis annual incidence has been declining in the EU—8346 cases were recorded in 2008, the vast majority of them caused by Yersinia enterocolitica