S1 De voorjaarsbijeenkomst van de Nederlandse ... - NVMM

2. Hamilton HL, Schwartz KJ, Dillard JP. J Bacteriol
2001;183:4718-26.
3. Hamilton HL, Dominguez NM, Schwartz KJ, Hackett
KT, Dillard JP. Mol Microbiol 2005;55:1704-21.
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epidemiology of erythema migrans and tick bites, and
infection of ticks with Borrelia
A. Hofhuis 1 , W. van Pelt1 , D.W. Notermans1 , F. Borgsteede2 ,
J. van der Giessen 1
1Centre for Infectious Disease Control, National Institute
for Public Health and the Environment (RIVM), Bilthoven,
2Central Veterinary Institute, Lelystad
Since Lyme disease is not notifiable in the Netherlands,
retrospective studies have been carried out to determine
the occurrence of tick bites, erythema migrans and Lyme
disease. In 1995, 2002 and 2006, all general practitioners
in the Netherlands (approximately 8000) were asked to
complete a postal questionnaire on tick bites and erythema
migrans case-patients seen in the previous year. Based on
these survey responses, the incidence of erythema migrans
consultations was estimated at 39 per 100,000 population
in 1994, which doubled to 74 per 100,000 in 2001, and
tripled to 103 per 100,000 in 2005. The incidence of tick
bite consultations increased from 191 per 100,000 in 1994
to 372 per 100,000 in 2001, and continued to increase to
446 per 100,000 in 2005. The largest increase in tick bites
and erythema migrans was seen in the south and northeast
of the country, and several locations along the coast in the
west. Statistical analysis of ecological risk factors by local
government showed that the increase in tick bites and
erythema migrans was associated with increases in tourism,
places with horse riding facilities, and new forest in urban
regions. Annual counts of hospital admissions, obtained
from a database of the Dutch National Medical Register,
coincided geographically with locations where physicians
were consulted for tick bites and erythema migrans. The
estimated annual number of hospital admissions for Lyme
disease increased gradually from 118 patients in 1991 to 233
patients in 2002. From thereon, the number of patients
increased strongly to 517 patients in 2006. To study the
tick density and the dynamics of Borrelia infection in ticks
in different habitats, ticks were collected from the field by
dragging a blanket in four habitat areas in the Netherlands:
dunes, heather, forest, and a city park. Results from 2000
to 2004 showed that the lowest tick density was observed
in the heather area the highest tick density was found in
the dune area. Tick densities and infection rates of ticks
varied between years and types of vegetation, 0.8% to 11.5%
of the collected ticks were infected with Borrelia burgdorferi
sensu lato. In addition, other potentially pathogenic microorganisms
like Anaplasma/Ehrlichia (1%-15%), Rickettsia
Ned Tijdschr Med Microbiol 2008;16:Supplement
S46
(5%–60%), and Babesia (0%-1%) were also found, which
poses an increasing but unknown threat for public health.
To gain more insight in the infection risk of Borrelia and
other tick borne pathogens, a prospective study started
in 2007: the National Tick bites study. The study design
included approximately 160 general practices throughout
the Netherlands. Patients with an erythema migrans or
a tick bite are enrolled into the study to gain insight in
the risk of transmission of tick-borne micro-organisms
as detected in the collected ticks from these patients to
humans and to observe their serological and clinical
outcomes. As data collection is ongoing in 2008, only
preliminary results will be presented.
O120
Where is the origin of the Cryptococcus gattii Vancouver
Island outbreak?
F. Hagen 1 , E.E. Kuramae 1 , M. Bovers 1 , D.J.C. Gerits 1 ,
C.H.A. Gerritzen 1 , W. Meyer 2 , T. Boekhout 1
1
Dept. of Yeast Research, CBS Fungal Biodiversity Centre,
Utrecht, 2Westmead Hospital, Sydney, Australia
The pathogenic basidiomycetous yeast Cryptococcus gattii
may cause a life-threatening disease of the central nervous
system, lungs and skin in humans and animals. C. gattii is
found mainly in tropical and sub-tropical regions of South
America, Africa, Asia and Australia where it is endemic.
Recently, a cryptococcosis outbreak in both humans and
animals occurred on Vancouver Island (British Columbia,
Canada) (Kidd et al., PNAS 101, 2004). This outbreak was
shown to be caused by a rare genotype of C. gattii (AFLP6A
or RAPD VGIIa). The objective of this study was to find the
origin of the outbreak isolates.
A selection of thirty-four C. gattii outbreak isolates and
ninety C. gattii reference strains were analysed by AFLP.
The six different AFLP fingerprint analyses were carried
out in duplicate. Reproducible marker fragments were used
for population genetic analysis. In addition, polymorphic
fragments from the AFLP analyses were used to develop a
multilocus sequence typing (MLST) approach.
Fraser et al. (Nature 437, 2005) suggested that the
Vancouver Island outbreak isolates originated from
Australia. However, our results based on AFLP and MLST
analyses show that the outbreak isolates originated from
South America. South American isolates were found to be
ancestral to Australian and Asian isolates as well.
References
- Kidd SE, Hagen F, Tscharke RL, Huynh M, Bartlett
KH, Fyfe M, L.et al. A rare genotype of Cryptococcus
gattii caused the cryptococcosis outbreak on Vancouver
Island (British Columbia, Canada). Proc Natl Acad Sci
USA 2004;101:17258-63.