Gunnar Hasle

Oslo Travel Clinic

Ticks are important pathogen vectors, and large mammals and birds have the greatest potential for dispersing them. To study tick dispersal by migrating birds, we have analysed genetic variations in mitochondrial DNA control region from Ixodes ricinus from northward migrating blackbird, Turdus merula, and (European) robin, Erithacus rubecula, at the...

Background: Diarrhoea is a common medical problem affecting travellers to Asia, Africa and Latin America. The use of prophylactic antimicrobial agents may increase the risk of contracting resistant bacteria. Findings indicate that oligosaccharides, i.e. carbohydrate chains of 3-10 monosaccharides, reduce the risk of diarrhoea. Methods: We perfor...

Dispersal and gene flow are important mechanisms affecting the dynamics of vectors and their pathogens. Here, patterns of genetic diversity were analyzed in many North European populations of the tick, Ixodes ricinus. Population sites were selected within and between areas separated by geographical barriers in order to evaluate the importance of ti...

Background: Traveller's diarrhoea (TD) is the most common infectious problem for travellers, and we lack effective ways of preventing it, apart from antibiotic prophylaxis. This study aims to quantify the risk reduction of a hypothetic TD vaccine Norwegian travellers are willing to pay for. Methods: 1204 clients at Reiseklinikken responded to a...

In Evidence-based medicine, a certain treatment is indicated for patients «of a certain category». The art of medicine is evidence-based decisions of what is the best for your patient. If we only had to follow rules, we could have been replaced by machines. Dilemma: When breaking a rule, you are liable to legal persecution. In this lecture I presen...

Tourism may potentially damage nature and local culture. Advices concerning responsible tourism should be a natural part of a travel medicine consultation, in accordance with the World Tourism Organization (UNWTO) for the promotion of responsible, sustainable and universally accessible tourism. In this context we emphasize tourism in temperate and...

Birds, particularly passerines, can be parasitized by Ixodid ticks, which may be infected with tick-borne pathogens, like Borrelia spp., Babesia spp., Anaplasma, Rickettsia/Coxiella, and tick-borne encephalitis virus. The prevalence of ticks on birds varies over years, season, locality and different bird species. The prevalence of ticks on differen...

At Oslo Travel Clinic, the largest vaccination clinic in Norway, the annual number of immunizations against Japanese Encephalitis was significantly reduced after the introduction of Ixiaro®. We assume that this is due to the higher cost.

Bovine babesiosis is regarded as a limited health problem for Norwegian cows, and the incidence has decreased markedly since the 1930s. Rare cases of babesiosis in splenectomised humans from infection with Babesia divergens and B.venatorum have been described. The objective of this study was to determine whether birds can introduce Babesia-infected...

Birds are capable of transporting ticks and, consequently, tick-borne pathogens over long distances and across geographical barriers such as oceans and deserts. The purpose of this study was to assess the prevalence of Borrelia spp. in ticks transported by birds by using PCR. A total of 9768 northward-migrating passerine birds was examined for tick...

The incidence of bovine babesiosis, caused by Babesia divergens (Apicomplexa: Piroplasmida) has decreased markedly since the 1930 s, but may re-emerge as a consequence of climate change and changes in legislation and pasturing practices. This is a potentially serious disease, with both economical and animal welfare consequences. Therefore, there is...

Ticks can be transported over large distances and across geographical barriers by avian hosts. During the spring migrations of 2003 to 2005, 9,768 passerine birds from 4 bird observatories along the southern coastline of Norway were examined for ticks. Altogether, 713 birds carried a total of 517 larvae and 1,440 nymphs. The highest prevalence of t...

Approximately 3000 birds, mainly passerines, caught in mist nets in the northern provinces of South Africa, were examined for ticks. A total of 178 ticks, belonging to 14 species, were recovered from 83 birds of 43 different species. Hyalomma rufipes was the most numerous tick, with 26 larvae and 109 nymphs collected, followed by Amblyomma marmoreu...

Object The exact numbers of travellers in different age groups travelling abroad are difficult to obtain. We used vacinees in the year 2007 at a centre for travel medicine in Oslo as a proxy-parameter representing the age distribution of the travelling population, and related this distribution to statistics on people seeking help from the Euro-Alar...

Norwegian travellers spend billions of Norwegian kroner on journeying to exotic locations, polluting the Earth's atmosphere in the process. Travel medicine centres earn money on this traffic. As a "penance" we have decided to do our bit for nature conservation by supporting the World Wide Fund for Nature (WWF) and the Rainforest Foundation Norway....

This investigation examines multiple paternity in Ixodes ricinus (Acari: Ixodidae). Previous studies have shown that multiple mating occurs in this tick, but this is the first evaluation of multiple paternity. Three family groups were examined by a panel of polymorphic microsatellite loci; all ticks were bred from wild-collected engorged females wi...

In April 2004, the Norwegian Institute of Public Health was notified about an outbreak of a respiratory illness among participants on a cultural-historical theme tour to Central America. One patient was examined in a Swedish hospital where the clinician suspected histoplasmosis, which later was verified by serology and by culture of Histoplasma cap...

Ixodes ricinus is the main vector for important infectious diseases in both humans and in animals. Microsatellite loci were isolated from a dinucleotide-enriched library made from I. ricinus sampled in Norway. Seventeen polymorphic microsatellites were further characterized among 24 individuals sampled from an island in the Oslofjord region. The nu...

To estimate the incidence of, identify risk factors for, and describe the clinical presentation of travel-associated African tick bite fever (ATBF), a rapidly emerging disease in travel medicine, we prospectively studied a cohort of 940 travelers to rural sub-Equatorial Africa. Diagnosis was based on suicide polymerase chain reaction and the detect...

As travellers seek ever more exotic destinations they are more likely to encounter dangerous animals. Compared to risks such as AIDS, traffic accidents and malaria, the risk is not so great; many travellers are, however, concerned about this and those who give pre-travel vaccines and advice should know something about it. This article is mainly bas...

Suspected epidemiological links between three cases of human immunodeficiency virus type 1 (HIV-1) infection were verified by the finding of a shared unique virus genotype. A probable male index case was not available for testing. Case 1 was a female sexual partner of the index case. Case 2 was an adult son of case 1. Case 3 was a female sexual par...

We report on 8 Norwegian travellers to Southern Africa with African tick-bite fever (ATBF), a recently described spotted fever group rickettsiosis. All patients had acute flu-like symptoms and developed I or multiple inoculation eschars. The patients were treated with either doxycycline or ciprofloxacin, and all recovered. The diagnosis of ATBF was...

Tick-borne rickettsioses are important zoonoses in many tropical and subtropical areas. There has recently been an increase in the number of reported cases among tourists returning to Scandinavia. In this article we present all five serologically confirmed cases of tick-borne rickettsioses imported into Norway in 1997. The patients were Norwegian t...

During the last six years we have registered 237 persons with acute hepatitis A in Oslo, 96 of them with non-Scandinavian names. The number with non-Scandinavian names is increasing. Almost all the hepatitis A patients with non-Scandinavian names are children, and two of three had been infected in Pakistan. Adult immigrants from countries where hep...

The article briefly reviews the literature on risk of contracting HIV through heterosexual contacts when travelling abroad. Condoms seems to provide maximum 90% protection against HIV. The risk of contracting HIV during a single intercourse may be very high (about 50%) if the HIV-positive person has genital ulcer disease. The author disagrees with...