Published Date: 2007-05-06 11:00:02
Subject: PRO/AH/EDR> Puumala virus infections - Germany
Archive Number: 20070506.1463
PUUMALA VIRUS INFECTIONS - GERMANY
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Thur 3 May 2007
Source: Eurosurveillance Weekly Release, Vol. 12 No 5. [edited]
[The above cited article contains an interesting
report of the hantavirus situation in Germany
this year (2007); excerpts are given below. - Mod.TY]
Hantaviruses (family Bunyaviridae) are
rodent-borne pathogens and occur worldwide.
Hantavirus infections in Europe and Asia can
result in a hemorrhagic fever with renal syndrome
(HFRS) of different severity. In Germany, the
predominant species is Puumala virus. Its main
reservoir is in bank voles (_Myodes glareolus_),
which predominantly live in forested areas dominated by deciduous trees.
The disease is characterised by an abrupt onset,
and the major symptoms include fever, abdominal
pain and other gastrointestinal symptoms,
headache, and back pain. Patients occasionally
develop acute renal failure that may require
haemodialysis. The virus is transmitted to humans
through inhalation of aerosolised rodent faeces.
It is reported that in endemic areas the
incidence of hantavirus infections among humans
is related to the size of the bank vole
population and prevalence of the virus . Peaks
in the bank vole population occur every 3 to 4
years and may result in an increase in human cases.
In Germany, the number of notified hantavirus
infections has considerably increased since the
beginning of the year 2007. Laboratory-confirmed
symptomatic hantavirus infections are mandatorily
notifiable since 2001 . Laboratory diagnosis
is based either on detection of nucleic acid, a
marked rise of IgG-antibodies in a paired sample,
or detection of IgM- or IgA-antibodies confirmed by IgG-antibodies.
In the period from 1 Jan 2007 to 15 Apr 2007, 164
symptomatic hantavirus cases were reported to the
Robert Koch-Institute. In the comparable time
period of the years 2001 to 2006, the mean number
of reported cases was only 38 (minimum: 13 cases
in 2006, maximum: 88 cases in 2005).
Of the 164 symptomatic hantavirus cases, 127 (77
percent) were male and 115 (70 percent) were
between 30 and 59 years old. No hantavirus cases
were reported in children younger than 10 years
of age. Age and sex distribution of hantavirus
cases in 2007 was not different to previous
years. In the years 2001 to 2006, a total of 1319
cases was reported (73 percent males, 68 percent
aged 30-59 years). All hantavirus diseases (with
known species) in 2007 were caused by Puumala
virus (n of 157), for 7 (4 percent) cases the
causative virus could not be specified.
The majority of infections in 2007 (127 or 77
percent) were acquired in Baden-Wuerttemberg, a
federal state in the south-west of Germany.
Further cases were observed in Bavaria (19
cases), North-Rhine-Westphalia (9 cases), Lower
Saxony (7 cases), Hesse (one case) and
Mecklenburg Western-Pomerania (one case).
Hantavirus cases in Baden-Wuerttemberg were
mostly residents of the Swabian Alb or their
neighbouring regions, an area which is known to
be endemic for hantavirus infections [2,3,4].
The incidence fluctuated substantially in
different years and generally reached a maximum
between May and August. Years of high incidence
such as 2005 alternate with years of low activity such as 2006.
The patterns of hantavirus activity over time
show not only a significant variation in the
incidence but also in the regional distribution.
Since the beginning of 2001, a total of 1487
laboratory-confirmed symptomatic hantavirus
infections has been reported to the Robert Koch
Institute of which 670 (45 percent) occurred in
Baden-Wuerttemberg. Annual incidence rates in the
years 2001 to 2006 were highest for
Baden-Wuerttemberg, which reflects hantavirus
activity in the known endemic area of Baden-Wuerttemberg [5,6].
The increase of hantavirus infections in 2007
started early. Such an early increase of cases
had also been observed in 2002. Throughout the
whole year 2002, most cases (72 percent)
continued to occur in Baden-Wuerttemberg. In
2005, however, a year with an early case increase
and with the highest hantavirus activity so far,
high numbers of cases were also diagnosed in many
other federal states, including areas previously
not known to be endemic such as urban settings [7,8]
In the past, the incidence of human hantavirus
infections in Germany seems to be correlated with
the size of the bank vole populations. The
population in endemic areas shows annual
fluctuations. Usually, the bank vole population
that comes into contact with humans reaches its
maximum size in the summer. The winter season
2006/2007, however, was exceptionally mild and in
many endemic regions there was no snow cover on
the ground. In addition, there was an abundant
supply of beech mast in the autumn of 2006. Under
such conditions rodents have high survival rates
and breed earlier. This may have lead to an early
increase in the bank vole population and probably
also to a higher hantavirus prevalence. Moreover,
humans may have been more exposed to rodent
droppings due to increased outdoor activities
(recreational and occupational) in forests and
gardens resulting in higher case numbers during
the winter season 2006/07. It is unclear,
however, why the hantavirus infections among
humans so far appear to be restricted to the
endemic area in Baden-Wuerttemberg.
1. Olsson GE, White N, Hjalten J, Ahlm C. Habitat
factors associated with bank voles (Clethrionomys
glareolus) and concomitant hantavirus in northern
Sweden. Vector Borne Zoonotic Dis 2005;5(4):315-23.
2. RKI: Hantavirus-Erkrankungen: Deutliche
Zunahme zu Beginn des Jahres 2007 in
S�ddeutschland. [In German]. Epid Bull
2007;14:120. Available from:
3. Ulrich R, Meisel H, Sch�tt M, Schmidt J, Kunz
A, Klempa B, et al. Verbreitung von
Hantavirusinfektionen in Deutschland. [In
German]. Bundesgesundheitsblatt 2004;47: 661-670.
4. Kimmig P, Silva-Gonzalez R, Backe H, Brockmann
S, Oehme R, Ernst E, Mackenstedt U. Epidemiologie
der Hantaviren in Baden-Wuerttemberg. [In
German]. Gesundheitswesen 2001;63(2):107-12.
5. RKI: Hantavirus-Erkrankungen im Zeitraum 2001
bis 2005. [In German]. Epid Bull 2006;40:341-343.
6. Z�ller L, Faulde M, Meisel H, Ruh B, Kimmig P,
Schelling U, Zeier M, Kulzer P, Becker C,
Roggendorf M, Bautz EKF, Kr�ger DH, Darai G.
Seroprevalence of hantavirus antibodies in
Germany as determined by a new recombinant enzyme
immunoassay. Eur J Clin Microbiol Inf Dis 1995;14:303-315.
7. Mailles A, Abu Sin M, Ducoffre G, Heyman P,
Koch J, Zeller H. Larger than usual increase in
cases of hantavirus infections in Belgium, France
and Germany, June 2005. Euro Surveill 2005;10
(7):E050721.4. Available from:
8. RKI: Bundesweite Fall-Kontroll-Studie zu
Verbreitung und Risikofaktoren von
Hantavirus-Infektionen. [In German]. Epid Bull
2006;40:344-346. Available from:
9. Landesgesundheitsamt Baden-Wuerttemberg:
H�ung von Hantavirus-Erkrankungen in
informiert �ber die Hintergr�nde. 27.04.2007. [In
[Byline: J Koch (KochJ@rki.de)1, SO Brockmann2, C Winter2, P Kimmig2, K Stark1
1. Robert Koch-Institut, Berlin, Germany
2. Staatliches Gesundheitsamt (State Health
Office), Baden-Wuerttemberg, Stuttgart, Germany]
[One wonders if this Puumala virus case increase
is a harbinger of climate warming
consequences. Time will tell. Figures and the
table and a map of Germany showing areas of cases
is available in the original article which can be
accessed at the URL given in the source, above.
Images of the bank vole reservoir of Puumala
virus in Germany can be accessed at: