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Featured researches published by Heli Siikamäki.


The Journal of Infectious Diseases | 2007

Severe Dengue Virus Infection in Travelers: Risk Factors and Laboratory Indicators

Ole Wichmann; Joaquim Gascón; Mirjam Schunk; Sabino Puente; Heli Siikamäki; Ida Gjø; Rogelio López-Vélez; Joannes Clerinx; Gabriele Peyerl-Hoffmann; Anders Sundøy; Blaise Genton; Peter Kern; Guido Calleri; Miguel de Górgolas; Nikolai Mühlberger; Tomas Jelinek

BACKGROUND Dengue fever is the most common arboviral disease in travelers. In countries where dengue virus is endemic, sequential (secondary) infections with different dengue virus serotypes are associated with disease severity. Data on severity and secondary infection rates in a population of travelers are lacking. METHODS Intensified surveillance of dengue fever in travelers was performed within the European Network on Surveillance of Imported Infectious Diseases. Data were collected at 14 European clinical referral centers between 2003 and 2005. RESULTS A total of 219 dengue virus infections imported from various regions of endemicity were reported. Serological analysis revealed a secondary immune response in 17%. Spontaneous bleeding was observed in 17 (8%) patients and was associated with increased serum alanine and aspartate aminotransferase levels and lower median platelet counts. Two (0.9%) patients fulfilled the World Health Organization (WHO) case definition for dengue hemorrhagic fever. However, 23 (11%) travelers had severe clinical manifestations (internal hemorrhage, plasma leakage, shock, or marked thrombocytopenia). A secondary immune response was significantly associated with both spontaneous bleeding and other severe clinical manifestations. CONCLUSIONS In travelers, severe dengue virus infections are not uncommon but may be missed if the WHO classification is strictly applied. High liver enzyme levels and low platelet counts could serve as indicators of disease severity.


Malaria Journal | 2004

Epidemiology and clinical features of vivax malaria imported to Europe: Sentinel surveillance data from TropNetEurop

Nikolai Mühlberger; Tomas Jelinek; Joaquim Gascón; M Probst; T Zoller; Mirjam Schunk; Jiri Beran; Ida E. Gjørup; Ron H. Behrens; Joannes Clerinx; Anders Björkman; Paul McWhinney; Alberto Matteelli; Rogelio López-Vélez; Zeno Bisoffi; Urban Hellgren; Sabino Puente; Matthias L. Schmid; Bjørn Myrvang; Ml Holthoff-Stich; Hermann Laferl; C. Hatz; Herwig Kollaritsch; A. Kapaun; J. Knobloch; J Iversen; Kotlowski A; Djm Malvy; Peter Kern; G. Fry

BackgroundPlasmodium vivax is the second most common species among malaria patients diagnosed in Europe, but epidemiological and clinical data on imported P. vivax malaria are limited. The TropNetEurop surveillance network has monitored the importation of vivax malaria into Europe since 1999.ObjectivesTo present epidemiological and clinical data on imported P. vivax malaria collected at European level.Material and methodsData of primary cases of P. vivax malaria reported between January 1999 and September 2003 were analysed, focusing on disease frequency, patient characteristics, place of infection, course of disease, treatment and differences between network-member countries.ResultsWithin the surveillance period 4,801 cases of imported malaria were reported. 618 (12.9%) were attributed to P. vivax. European travellers and immigrants were the largest patient groups, but their proportion varied among the reporting countries. The main regions of infection in descending order were the Indian subcontinent, Indonesia, South America and Western and Eastern Africa, as a group accounting for more than 60% of the cases. Regular use of malaria chemoprophylaxis was reported by 118 patients. With 86 (inter-quartile range 41–158) versus 31 days (inter-quartile range 4–133) the median symptom onset was significantly delayed in patients with chemoprophylaxis (p < 0.0001). Common complaints were fever, headache, fatigue, and musculo-skeletal symptoms. All patients survived and severe clinical complications were rare. Hospitalization was provided for 60% and primaquine treatment administered to 83.8% of the patients, but frequencies varied strongly among reporting countries.ConclusionsTropNetEurop data can contribute to the harmonization of European treatment policies.


Lancet Infectious Diseases | 2009

Infection control in the management of highly pathogenic infectious diseases: consensus of the European Network of Infectious Disease

Philippe Brouqui; Vincenzo Puro; Francesco Maria Fusco; Barbara Bannister; Stephan Schilling; P Follin; René Gottschalk; Robert Hemmer; Helena C. Maltezou; K Ott; Renaat Peleman; Christian Perronne; Gerard Sheehan; Heli Siikamäki; Peter Skinhoj; Giuseppe Ippolito

Summary The European Network for Infectious Diseases (EUNID) is a network of clinicians, public health epidemiologists, microbiologists, infection control, and critical-care doctors from the European member states, who are experienced in the management of patients with highly infectious diseases. We aim to develop a consensus recommendation for infection control during clinical management and invasive procedures in such patients. After an extensive literature review, draft recommendations were amended jointly by 27 partners from 15 European countries. Recommendations include repetitive training of staff to ascertain infection control, systematic use of cough and respiratory etiquette at admission to the emergency department, fluid sampling in the isolation room, and analyses in biosafety level 3/4 laboratories, and preference for point-of-care bedside laboratory tests. Children should be cared for by paediatricians and intensive-care patients should be cared for by critical-care doctors in high-level isolation units (HLIU). Invasive procedures should be avoided if unnecessary or done in the HLIU, as should chest radiography, ultrasonography, and renal dialysis. Procedures that require transport of patients out of the HLIU should be done during designated sessions or hours in secure transport. Picture archiving and communication systems should be used. Post-mortem examination should be avoided; biopsy or blood collection is preferred.


Malaria Journal | 2007

The low and declining risk of malaria in travellers to Latin America: is there still an indication for chemoprophylaxis?

Ron H. Behrens; Bernadette Carroll; Jiri Beran; Olivier Bouchaud; Urban Hellgren; Christoph Hatz; Tomas Jelinek; Fabrice Legros; Nikolai Mühlberger; Bjørn Myrvang; Heli Siikamäki; Leo G. Visser

A comparison was made between local malaria transmission and malaria imported by travellers to identify the utility of national and regional annual parasite index (API) in predicting malaria risk and its value in generating recommendations on malaria prophylaxis for travellers.Regional malaria transmission data was correlated with malaria acquired in Latin America and imported into the USA and nine European countries. Between 2000 and 2004, most countries reported declining malaria transmission. Highest APIs in 2003/4 were in Surinam (287.4) Guyana (209.2) and French Guiana (147.4). The major source of travel associated malaria was Honduras, French Guiana, Guatemala, Mexico and Ecuador. During 2004 there were 6.3 million visits from the ten study countries and in 2005, 209 cases of malaria of which 22 (11%) were Plasmodium falciparum. The risk of adverse events are high and the benefit of avoided benign vivax malaria is very low under current policy, which may be causing more harm than benefit.


Journal of Clinical Virology | 2008

Japanese encephalitis in a Finnish traveler on a two-week holiday in Thailand

Ville A. Lehtinen; Eili Huhtamo; Heli Siikamäki; Olli Vapalahti

Japanese encephalitis (JE) virus is a mosquito-borne flavivirus, and one of the leading causes of epidemic encephalitis in Southeast Asia. Reports of symptomatic JEV encephalitis in tourists have been rare. We describe a case of symptomatic JE transmitted in 2004 during a short two-week trip to common tourist attractions in Thailand.


Journal of Travel Medicine | 2010

Imported Malaria in Finland 1995 to 2008: An Overview of Surveillance, Travel Trends, and Antimalarial Drug Sales

Sandra Guedes; Heli Siikamäki; Anu Kantele; Outi Lyytikäinen

BACKGROUND To improve pre-travel advice, we analyzed nationwide population-based surveillance data on malaria cases reported to the National Infectious Disease Register of Finland (population 5.3 million) during 1995 to 2008 and related it to data on traveling and antimalarial drug sales. METHODS Surveillance data comprised information on malaria cases reported to the National Infectious Disease Register during 1995 to 2008. Traveling data were obtained from Statistics Finland (SF) and the Association of Finnish Travel Agents (AFTA). SF data included information on overnight leisure trips to malaria-endemic countries during 2000 to 2008. AFTA data included annual number of organized trips during 1999 to 2007. Quarterly numbers of antimalarial drug sales were obtained from the Finnish Medicines Agency. Descriptive and time series analyses were performed. RESULTS A total of 484 malaria cases (average annual incidence 0.7/100,000 population) were reported; 283 patients were Finnish- and 201 foreign-born. In all, 15% of all cases were children; 72% foreign- and 28% Finnish-born. Malaria infections were mostly acquired in Africa (76%). Among foreign-born cases, 89% of the infections were acquired in the region of birth. The most common species were Plasmodium falciparum (61%) and Plasmodium vivax (22%). Although traveling to malaria-endemic areas increased, no increase occurred in malaria cases, and a decreasing trend was present in antimalarial drug sales. Traveling to malaria-endemic countries and drug sales followed the same seasonal pattern, with peaks in the first and last quarter of the year. CONCLUSIONS More efforts should be focused on disseminating pre-travel advice to immigrants planning to visit friends and relatives and travelers on self-organized trips.


Emerging Infectious Diseases | 2010

Fatal Babesiosis in Man, Finland, 2004

Karita Haapasalo; Pekka Suomalainen; Antti Sukura; Heli Siikamäki; T. Sakari Jokiranta

We report an unusual case of human babesiosis in Finland in a 53-year-old man with no history of splenectomy. He had a rudimentary spleen, coexisting Lyme borreliosis, exceptional dark streaks on his extremities, and subsequent disseminated aspergillosis. He was infected with Babesia divergens, which usually causes bovine babesiosis in Finland.


Emerging Infectious Diseases | 2008

Molecular Epidemiology of Dengue Virus Strains from Finnish Travelers

Eili Huhtamo; Nathalie Y. Uzcátegui; Heli Siikamäki; Auli Saarinen; Heli Piiparinen; Antti Vaheri; Olli Vapalahti

Molecular Epidemiology of Dengue Virus Strains from Finnish Travelers


Journal of Travel Medicine | 2011

Fever in travelers returning from malaria-endemic areas: don't look for malaria only.

Heli Siikamäki; Pia Kivelä; Pyry Sipilä; Annikaisa Kettunen; M. Katariina Kainulainen; Jukka Ollgren; Anu Kantele

BACKGROUND Returning travelers with fever pose challenges for clinicians because of the multitude of diagnostic alternatives. Case data in a Finnish tertiary hospital were analyzed in order to define the causes of fever in returned travelers and to evaluate the current diagnostic approach. METHODS A retrospective study of patient records comprised 462 febrile adults who, after traveling in malaria-endemic areas, were admitted to the Helsinki University Central Hospital (HUCH) emergency room from 2005 to 2009. These patients were identified through requests for malaria smear. RESULTS The most common groups of diagnoses were acute diarrheal disease (126 patients/27%), systemic febrile illness (95/21%), and respiratory illness (69/15%). The most common specific main diagnosis was Campylobacter infection (40/9%). Malaria was diagnosed in 4% (20/462). Blood culture was positive for bacteria in 5% of those tested (21/428). Eight patients were diagnosed with influenza. HIV-antibodies were tested in 174 patients (38%) and proved positive in 3% of them (5/174, 1% of all patients). The cause of fever was noninfectious in 12 (3%), remaining unknown in 116 (25%). Potentially life-threatening illnesses were diagnosed in 118 patients (26%), the strongest risk factors were baseline C-reactive protein (CRP) ≥100 (OR 3.6; 95% CI 2.0-6.4) and platelet count ≤140 (OR 3.8; 95% CI 2.0-7.3). Nine patients (2%) were treated in high dependency or intensive care units; one died of septicemia. Forty-five patients (10%) had more than one diagnosis. CONCLUSION The high proportion of patients with more than one diagnosis proves the importance of careful diagnostics. Every fourth returning traveler with fever had a potentially life-threatening illness. Septicemia was as common as malaria. The proportion of HIV cases exceeded the prevalence in population for which Centers for Disease Control and Prevention, USA (CDC) recommends routine HIV testing. Both blood cultures and HIV tests should be considered in febrile travelers.


Malaria Journal | 2013

Imported malaria in Finland 2003-2011: prospective nationwide data with rechecked background information

Heli Siikamäki; Pia Kivelä; Outi Lyytikäinen; Anu Kantele

BackgroundAlthough described in several reports, imported malaria in Europe has not been surveyed nationwide with overall coverage of patients and individually rechecked background information. Plasmodium falciparum infections have been reported despite regularly taken appropriate chemoprophylaxis, yet the reliability of such questionnaire-based retrospective data has been questioned. This was the starting-point for conducting a prospective nationwide survey of imported malaria where compliance data was double-checked.MethodsData was collected on all cases of imported malaria confirmed and recorded by the reference laboratory of Finland (population 5.4 million) from 2003 to 2011, and these were compared with those reported to the National Infectious Disease Register (NIDR). Background information was gathered by detailed questionnaires sent to the clinicians upon diagnosis; missing data were enquired by telephone of clinician or patient. Special attention was paid to compliance with chemoprophylaxis: self-reported use of anti-malarials was rechecked for all cases of P. falciparum.ResultsA total of 265 malaria cases (average annual incidence rate 0.5/100,000 population) had been recorded by the reference laboratory, all of them also reported to NIDR: 54% were born in malaria-endemic countries; 86% were currently living in non-endemic regions. Malaria was mainly (81%) contracted in sub-Saharan Africa. Plasmodium falciparum proved to be the most common species (72%). Immigrants constituted the largest group of travellers (44%). Pre-travel advice was received by 20% of those born in endemic regions and 81% of those from non-endemic regions. Of those with P. falciparum, 4% reported regular use of appropriate chemoprophylaxis (mefloquine or atovaquone/proguanil or doxycycline for regions with chloroquine-resistant and atovaquone/proguanil or doxycycline for regions with mefloquine-resistant P. falciparum); after individual rechecking, however, it was found that none of them had been fully compliant.ConclusionsInformation on compliance with chemoprophylactic regimen cannot be relied on, and it should be rechecked if malaria is suspected. The results of the present study suggest that mefloquine, atovaquone/proguanil and doxycycline are effective as chemoprophylaxis against P. falciparum malaria, when taken conscientiously.

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Anu Kantele

University of Helsinki

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René Gottschalk

Centers for Disease Control and Prevention

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Giuseppe Ippolito

Istituto Superiore di Sanità

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K Ott

Centers for Disease Control and Prevention

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V. Puro

National Institutes of Health

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Helena C. Maltezou

Centers for Disease Control and Prevention

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P Follin

Centers for Disease Control and Prevention

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