Tickborne Encephalitis Virus, Northeastern Italy
http://www.100md.com
《传染病的形成》
University of Udine, Udine, Italy
Hospital of San Daniele, San Daniele, Italy
Hospital of Pordenone, Pordenone, Italy
San Antonio Abate Hospital, Tolmezzo, Italy
Hospital of Udine, Udine, Italy
From July 2003 through November 2005, 20 cases of TBEV infection were detected; their demographic, epidemiologic, and clinical characteristics are given in the Table. Cases occurred throughout the year, with a biphasic peak in June and September–November. A biphasic clinical course was reported in 10 patients. The median period between tick bite and date of referral to hospital was 22 days (range 15–46 days). Seventeen cases were classified as confirmed, 2 as probable, and 1 case could not be classified because symptoms started after tick season (December) (6). Two patients were coinfected with Borrelia burgdorferi.
The most common symptoms were fever, headache, nausea, vomiting, and myalgia; the most common central nervous system signs were stiff neck, irritability, and limb paresis. Five patients only reported headache and fever without neurologic signs. Lumbar puncture, performed in 15 patients, showed mild pleocytosis with neutrophil predominance in 13 patients, elevated protein level in 14 patients, and normal glucose level in all.
The clinical syndrome was classified, in accordance with Kaiser et al., into febrile form (4 cases), aseptic meningitis (3 cases), encephalitis (2 cases), meningoencephalitis (8 cases), and meningoencephalomyelitis (3 cases) (7). None of the patients died, but 3 required respiratory support in the intensive care unit. Outcome was favorable for 9 patients; major neurologic sequelae were observed in 6 and minor sequelae in 5.
During the past 20 years, TBEV has reemerged in several European areas that had been disease free (1,8). In FVG, which borders disease-endemic areas such as Slovenia and Austria, the first cases of TBEV infection were documented recently (4). Several explanations, in addition to the well-established role of climate change, can be proposed (1). First, in Slovenia, after the end of the Communist regime, recreational activities increased considerably, with the creation of natural parks and hunting grounds, densely populated with deer, chamois, rodents, foxes, and other wild animals that can easily cross national borders (9). Second, after the 1976 earthquake that destroyed a large number of mountain villages in FVG, economic activities were progressively concentrated in the plains of the region, which rapidly increased urbanization of the plains towns. As a consequence, the mountains in the northern part of the region were progressively abandoned by humans and returned to wilderness. A final possible explanation is that TBEV cases were undiagnosed because awareness among local physicians was low; however, this variable likely played a minor role, since a recent serologic survey of persons at high risk (forest rangers) yielded a low positivity ratio (3). If even workers at risk had a low seroprevalence, TBEV cases were likely uncommon in the region.
The implementation of a regional active surveillance system allows the highest sensitivity in assessing the epidemiologic features of TBEV infections, which are characterized by highly disease-endemic microfoci in areas free of the problem (10). Precisely defining areas where risk is particularly will lead to optimal use of prevention programs and design of educational programs for residents, tourists, and healthcare workers.
Acknowledgments
We are grateful to Maria Grazia Ciuffolini for TBEV serologic testing (hemagglutination-inhibition antibody test and neutralization assay).
References
Günther G, Haglund M. Tick-borne encephalopathies: epidemiology, diagnosis, treatment and prevention. CNS Drugs. 2005;19:1009–32.
Cristofolini A, Bassetti D, Schallenberg G. Zoonoses transmitted by ticks in forest workers (tick-borne encephalitis and Lyme borreliosis): preliminary results. Med Lav. 1993;84:394–402.
Cinco M, Barbone F, Ciufolini M, Mascioli M, Anguero Rosenfeld M, Stefanel P, et al. Seroprevalence of tick-borne infections in forestry rangers from northeastern Italy. Clin Microbiol Infect. 2004;10:1056–61.
Beltrame A, Cruciatti B, Ruscio M, Scudeller L, Cristini F, Rorato G, et al. Tick-borne encephalitis in Friuli Venezia Giulia, northeastern Italy. Infection. 2005;33:158–9.
Holzmann H, Kundi M, Stiasny K, Clement J, McKenna P, Kunz C, et al. Correlation between ELISA, hemagglutination inhibition, and neutralization tests after vaccination against tick-borne encephalitis. J Med Virol. 1996;48:102–7.
Stefanoff P, Eidson M, Morse DL, Zielinski A. Evaluation of tickborne encephalitis case classification in Poland. Euro Surveill. 2005;10:23–5.
Kaiser R. The clinical and epidemiological profile of tick-borne encephalitis in southern Germany 1994–98: a prospective study of 656 patients. Brain. 1999;122:2067–78.
Skarpaas T, Ljostad U, Sundoy A. First human cases of tickborne encephalitis, Norway. Emerg Infect Dis. 2004;10:2241–3.
Lesnicar G, Poljak M, Seme K, Lesnicar J. Pediatric tick-borne encephalitis in 371 cases from an endemic region in Slovenia, 1959 to 2000. Pediatr Infect Dis J. 2003;22:612–7.
Zeman P. Objective assessment of risk maps of tick-borne encephalitis and Lyme borreliosis based on spatial patterns of located cases. Int J Epidemiol. 1997;26:1121–9.(Anna Beltrame, Maurizio R)
Hospital of San Daniele, San Daniele, Italy
Hospital of Pordenone, Pordenone, Italy
San Antonio Abate Hospital, Tolmezzo, Italy
Hospital of Udine, Udine, Italy
From July 2003 through November 2005, 20 cases of TBEV infection were detected; their demographic, epidemiologic, and clinical characteristics are given in the Table. Cases occurred throughout the year, with a biphasic peak in June and September–November. A biphasic clinical course was reported in 10 patients. The median period between tick bite and date of referral to hospital was 22 days (range 15–46 days). Seventeen cases were classified as confirmed, 2 as probable, and 1 case could not be classified because symptoms started after tick season (December) (6). Two patients were coinfected with Borrelia burgdorferi.
The most common symptoms were fever, headache, nausea, vomiting, and myalgia; the most common central nervous system signs were stiff neck, irritability, and limb paresis. Five patients only reported headache and fever without neurologic signs. Lumbar puncture, performed in 15 patients, showed mild pleocytosis with neutrophil predominance in 13 patients, elevated protein level in 14 patients, and normal glucose level in all.
The clinical syndrome was classified, in accordance with Kaiser et al., into febrile form (4 cases), aseptic meningitis (3 cases), encephalitis (2 cases), meningoencephalitis (8 cases), and meningoencephalomyelitis (3 cases) (7). None of the patients died, but 3 required respiratory support in the intensive care unit. Outcome was favorable for 9 patients; major neurologic sequelae were observed in 6 and minor sequelae in 5.
During the past 20 years, TBEV has reemerged in several European areas that had been disease free (1,8). In FVG, which borders disease-endemic areas such as Slovenia and Austria, the first cases of TBEV infection were documented recently (4). Several explanations, in addition to the well-established role of climate change, can be proposed (1). First, in Slovenia, after the end of the Communist regime, recreational activities increased considerably, with the creation of natural parks and hunting grounds, densely populated with deer, chamois, rodents, foxes, and other wild animals that can easily cross national borders (9). Second, after the 1976 earthquake that destroyed a large number of mountain villages in FVG, economic activities were progressively concentrated in the plains of the region, which rapidly increased urbanization of the plains towns. As a consequence, the mountains in the northern part of the region were progressively abandoned by humans and returned to wilderness. A final possible explanation is that TBEV cases were undiagnosed because awareness among local physicians was low; however, this variable likely played a minor role, since a recent serologic survey of persons at high risk (forest rangers) yielded a low positivity ratio (3). If even workers at risk had a low seroprevalence, TBEV cases were likely uncommon in the region.
The implementation of a regional active surveillance system allows the highest sensitivity in assessing the epidemiologic features of TBEV infections, which are characterized by highly disease-endemic microfoci in areas free of the problem (10). Precisely defining areas where risk is particularly will lead to optimal use of prevention programs and design of educational programs for residents, tourists, and healthcare workers.
Acknowledgments
We are grateful to Maria Grazia Ciuffolini for TBEV serologic testing (hemagglutination-inhibition antibody test and neutralization assay).
References
Günther G, Haglund M. Tick-borne encephalopathies: epidemiology, diagnosis, treatment and prevention. CNS Drugs. 2005;19:1009–32.
Cristofolini A, Bassetti D, Schallenberg G. Zoonoses transmitted by ticks in forest workers (tick-borne encephalitis and Lyme borreliosis): preliminary results. Med Lav. 1993;84:394–402.
Cinco M, Barbone F, Ciufolini M, Mascioli M, Anguero Rosenfeld M, Stefanel P, et al. Seroprevalence of tick-borne infections in forestry rangers from northeastern Italy. Clin Microbiol Infect. 2004;10:1056–61.
Beltrame A, Cruciatti B, Ruscio M, Scudeller L, Cristini F, Rorato G, et al. Tick-borne encephalitis in Friuli Venezia Giulia, northeastern Italy. Infection. 2005;33:158–9.
Holzmann H, Kundi M, Stiasny K, Clement J, McKenna P, Kunz C, et al. Correlation between ELISA, hemagglutination inhibition, and neutralization tests after vaccination against tick-borne encephalitis. J Med Virol. 1996;48:102–7.
Stefanoff P, Eidson M, Morse DL, Zielinski A. Evaluation of tickborne encephalitis case classification in Poland. Euro Surveill. 2005;10:23–5.
Kaiser R. The clinical and epidemiological profile of tick-borne encephalitis in southern Germany 1994–98: a prospective study of 656 patients. Brain. 1999;122:2067–78.
Skarpaas T, Ljostad U, Sundoy A. First human cases of tickborne encephalitis, Norway. Emerg Infect Dis. 2004;10:2241–3.
Lesnicar G, Poljak M, Seme K, Lesnicar J. Pediatric tick-borne encephalitis in 371 cases from an endemic region in Slovenia, 1959 to 2000. Pediatr Infect Dis J. 2003;22:612–7.
Zeman P. Objective assessment of risk maps of tick-borne encephalitis and Lyme borreliosis based on spatial patterns of located cases. Int J Epidemiol. 1997;26:1121–9.(Anna Beltrame, Maurizio R)