Lyme disease in Belluno 
Epidemiologic Study 
LYME DISEASE 
IN BELLUNO - A NORTH-EASTERN 
ITALIAN PROVINCE 
D. Grazioli, C. Balzan, S. Maso and L. Simioni 
ABSTRACT 
Lyme borreliosis (LB) has a world-wide distribution and may be seen where ixodes ticks are found. Ixodes 
ricinus is the vector: ticks have been found in the mountains and Borrelia burgdorferi was isolated from the 
vector. Our survey focuses on Belluno Province in Veneto Region, an Alpine mountain Region in the North-
East of Italy. Data on LB reported from 1977 to 1993 were examined according to incidence, localization 
and seasonal distribution of ticks-bites as well as age and sex of the patients. LB diagnosis was made in 284 
subjects: in 256 cases infection occurred in Belluno Province and in 28 cases outside of the Province. In 178 
cases (63%) the diagnosis was made in Dermatologic Out-Patient's Department. The disease was recognized 
by the presence of erythema migrans (EM). 
LB prevalence has been increasing from 10/ 100 000 in 1988 to 29/ 100 000 in 1992. Most of the people 
who developed borreliosis were in the 40-70 age range, 53% were females. The authors suppose that roe 
deers are mainly responsible for spreading LB in the Belluno Province. 
KEY WORDS 
Lyme bmreliosis, Belluno, Italy, roe deer 
INTRODUCTION 
The disease is named Lyme disease or Lyme 
borreliosis (LB) after an unusual outbreak of arthritis 
took place near the city Lyme (Connecticut, USA) 
in 1977 (1,2). Our survey focuses on the Belluno 
Province, an Alpine mountain region in the North-
East of ltaly (Figure 1). It is a hilly district at the 
foot of the Dolomites with wooded and grazing 
land. Villages are usually located in the mountains 
and they are surrounded by fields. Deciduous trees 
acta dennatovenerologica A.P.A. Vol 6, 97, No 3 
followed by conifers and grassland are situated at 
700-1000 meters above the sea level, where no 
major settlement is located. Agriculture and stock-
farming, major industries of the past, have now 
been superseded by new activities, like handicraft 
industries, services and tourism. This new environment 
modified the approach and the relationship bern:een 
the people and the surrounding wildlife. 
We collected and analyzed all available data on 
LB reported cases in the region from 1977 to 1993. 
111 
Lyme disease in Belluno 
D 
.. 
Fig. l. Geographical position of Belluno province in 
the North-East of Italy. 
284 cases have been found: 28 occurred outside of 
the Province of Belluno, 256 inside. In the present 
report only patients infected in Belluno region are 
included. 
AIMS 
l. To study the incidence and the prevalence of LB 
in the Province of Belluno. 
2. To identify age and sex distribution of subjects 
affected by LB. 
N 
60 
55 
,o 
U 45 
M 
8 40 
E 
R 35 
O 30 
F 
15 
C 
A 20 
s 
E 1' 
s 
10 
,. 
JI " 
" 
24 23 ,. 
~ ~ ~ ~ m ~ ~ ~ ~ ~ m ~ ~ ~ ~ w ~ 
YEARS 
~ NUMB[R OF CASES 
Fig. 2. Yearly distribution of illness occurred in Belluno 
province from 1977 to 1993. 
112 
3. To find if there is any seasonal distribution of 
infected tick bites. 
SUBJECTS AND METHODS 
The population of the investigated area is about 
200 000 inhabitants and no significant population 
changes happened since 1977. We analyzed all the 
data collected by Dermatologic diagnostic units, by 
the Hospital for lnfectious Disease, by Public Health 
Centers and by general practitioners in Belluno 
Province. Data related to hospitalized patients have 
been made available by the Computerized Data 
Processing Center of ULSS 2. The criteria for 
diagnosis of Lyme borreliosis have been the following: 
1 presence of EM or 
2 symptoms and signs of 2nd and 3rd stage of LB 
with borrelial antibodies in serum and/or in CSF . 
The diagnosis was made: 
- by dermatologists in 70% of cases (178/256) through 
clinical diagnosis of EM; 
- by attending physicians of Interna! Medicine, Infec-
tious Disease and Neurologic wards in 16% of cases 
( 42/256); diagnosis was made considering clinical 
and immunological data; 
- by Public Health Centers physicians in 10% of 
cases (26/256) diagnosing clinically EM; 
- by general practitioners in 4% of cases observing 
EM; 
The data collected by the different Health Centers 
included diagnosis, surname, first name, sex and age 
of the patients. Additional information e.g. area and 
'° 
35 
N 
u JO 
M 
B 
E " R 
o ,o 
r 
C " A 
s 
E 10 
s 
.. , 
,. 
JO 
12 
5 
f 
f 
10-19 20-29 J0-]9 40-49 50-59 60-69 
AGE 
LJ MALES • FEMALES 
Fig. 3. Distribution of patient according to sex and age 
when bitten in Belluno province. 
acta dennatovenerologica A.P.A. Vol 6, 97, No 3 
Lyme disease in Belluno 
N 
60 
" 
u ,o 
M 
B 45 
E 
R '° 
o 35 
F 
T 30 
I 
C 25 
K 
20 
B 
I IS 
T 
E JO 
s 
SPRING SUMMER AUTUMN 
~ TICKBITES 
Fig. 4. The number of the registered tick-bites according 
to the seasons of the year. 
season of the tick bite were obtained by a telephone 
interview. 
RESULTS 
According to collected data the LB was diagnosed 
in 284 subjects since 1977 until 1993. 256 occurred 
in Belluno Province and 28 outside this area. The 
incidence of LB has been increasing since 1977 
when only one case has been reported and reached 
its maximum with 58 cases reported in 1992 (Figure 
2). In the past five years LB prevalence changed 
from 10/100 000 in 1988 to 29/100 000 in 1992. 
Females seem to be more often affected by LB 
than males (53% versus 47% ). It appears that 
females develop LB more often in the 40-70 age 
range (55 %, 89/163) while males are more involved 
in the 20-40 age range (55%, 30/55) (Fig. 3). 
190 out of 256 patients (74%) who were reached 
by phone, answered our additional questions. 139/ 
190 (73%) remembered the area of the tick-bite, 
140/190 (74%) remembered in which season they 
were bitten. Most of the people we interviewed 
(71 % ) have been bitten during spring and summer; 
only 4% suffered a tick bite in winter. 
DISCUSSION 
In Italy, as well as in Europe, Ixodes ricinus is 
the vector of Borrelia burgdorferi (3,4) and ticks of 
this species have been identified in the mountains 
of our region. Borrelia burgdorferi was isolated in 
the vectors in North-East of Italy: Friuli Venezia 
Giulia and Alto Adige ( 4,5) and in the South of 
Austria: Styria (6). In ltaly, from 1977 to 1993, 168 
cases of LB were identified in Liguria, 455 in Friuli 
Venezia Giulia, 25 in Toscana (7, 8) 7 in the 
Province of Pavia. On the basis of retrospective 
analysis of collected data we identified from 1977 to 
1993 284 cases of LB in the Province of Belluno. 
Our data point out that in Belluno Province 
prevalence increased from 10/100 000 in 1988 to 29/ 
100 000 in 1992, showing a slight decrease to 16/100 
000 in 1993. According to the figures it appears 
that LB disease incidence increased since 1977, but 
we should keep in mind that much more attention 
has recently been paid to LB diagnosis: so the 
increase is probably not only due to spreading of 
the disease. Cutaneous involvement is prevalent 
compared to other clinical symptoms. According to 
our data on infected ticks, the risk of acquiring LB 
is high along Piave River and especially on the left 
bank. 
In this area ticks are particularly abundant. Some 
authors (9) point out that the risk for roe deers of 
getting ectoparasites, and especially ticks, is higher 
on the left bank of Piave River, from its sources, 
near Mount Paralba, to Quero gorge. Animals living 
there are more infested by ticks then those living in 
other areas of Belluno Province, such as Comelico, 
Ampezzano and Upper Agordino. 
CONCLUSION 
We suppose that roe deers have a leading role in 
spreading LB in Belluno Province. 
Abundance of ticks can be considered as a resultant 
of the change in the ecological system due to great 
socio-economic modifications in the last few decades 
(10). 
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AUTHORS' ADDRESSES 
114 
Domenico Grazioli MD, Public Health Department of ULSS n. 2, Via Borgo Ruga 28, 32032 Feltre 
(Belluno ), ltaly 
Corrado Balzan MD, Physician ULSS n. 2, Via Roma 29, 32028 Trichiana (Belluno ), Italy 
Stefano Maso MD, same address 
Livio Simioni MD, Department of Internal Medicine, S. Maria del Prato Hospital, Via Bagnols sur 
Ceze 3, 32032 Feltre (Belluno ), Italy 
acta dennatovenerologica A.P.A. Vol 6, 97, No 3