Pathophysiological aspects of Platelet-Mediated Thrombosis and Bleeding in Essential Thrombocythemia:

Thrombocytosis, i.e. an elevation of the platelet count, is a common finding in clinical practice. In general, patients with thrombocytosis are distinguished into two main categories, primarily based on the cause underlying the increased platelet count. The term "reactive thrombocytosis (RT)" has commonly been applied to the condition of an increased platelet count after a period of bone marrow suppression associated with chronic or acute inflammation or infections, malignant diseases, hemorrhage, iron deficiency, or after splenectomy. In contrast, the condition in those patients in whom there is a clonal proliferative drive to enhanced platelet production is termed "thrombocythemia". Thrombocythemia may occur in its primary form (also known as essential thrombocythemia) or may accompany any of the other myeloproliferative disorders polycythemia vera (PV), myeloid metaplasia with myelofibrosis (MMM), chronic myeloid leukemia (CML) as well as myelodysplastic syndromes. The clinical course, treatment and prognosis vary considerably for patients with reactive thrombocytosis, myeloproliferative disorders and myelodysplastic syndromes. Therefore, a thorough analysis of the cause for the increased platelet count is warranted. This thesis will deal with essential thrombocythemia (ET), a myeloproliferative disorder characterized by a sustained elevation of the platelet count and a paradoxical predisposition to both thrombotic and bleeding complications

The knowledge, attitudes and practices of wintersun vacationers to the Gambia toward prevention of malaria: Is it really that bad?

Background: Each year clusters of imported malaria cases are observed in Dutch wintersun vacationers returning from The Gambia. To gain more insight in the travel health preparation and awareness of these travellers, the knowledge, attitudes and practices (KAP) of this travel group was studied by analysing the data of the Continuous Dutch Schiphol Airport Survey. Methods. In the years 2002 to 2009 a questionnaire-based survey was conducted at the Dutch Schiphol Airport with the aim to study the KAP, i.e. accuracy of risk perception ("knowledge"), intended risk-avoiding behaviour ("attitude") and use of personal protective measures and malaria chemoprophylaxis ("practice") toward prevention malaria in travellers to The Gambia. Travellers to other high-risk destinations served as controls. Results: The KAP of travellers to The Gambia toward prevention of malaria was significantly better than that observed in other travellers. Trend analyses indicated that attitude improved over time in both groups but knowledge did not change. Only in travellers to high-risk countries other than The Gambia significant increases in protection rates were observed over time. Conclusions: The KAP of travellers to The Gambia toward prevention of malaria was better than that observed in travellers to destinations other than The Gambia. Trend analyses revealed a significant improvement of intended risk avoiding behaviour but not in protection rates or risk perception

Is paromomycin the drug of choice for eradication of Dientamoeba fragilis in adults?

Dientamoeba fragilis is a debated protozoan parasite that is often detected in stools of patients with chronic gastro-intestinal complaints. A retrospective follow-up study of a large cohort of patients was performed to better understand the natural course of the infection and possible treatment options. D. fragilis was spontaneously cleared in 41% of untreated cases. With an eradication rate of 98%, treatment with paromomycin appeared more effective than treatment with clioquinol (83%) or metronidazole (57%)

Trends in the knowledge, attitudes and practices of travel risk groups towards prevention of malaria: Results from the Dutch Schiphol airport survey 2002 to 2009

Background: Previous studies investigating the travellers knowledge, attitudes and practices (KAP) profile indicated an important educational need among those travelling to risk destinations. Initiatives to improve such education should target all groups of travellers, including business travellers, those visiting friends and relatives (VFRs), and elderly travellers. Methods: In the years 2002 to 2009, a questionnaire-based survey was conducted at the Dutch Schiphol Airport with the aim to study trends in KAP of travel risk groups towards prevention of malaria. The risk groups last-minute travellers, solo-travellers, business travellers, VFRs and elderly travellers were specifically studied. Results: A total of 3,045 respondents were included in the survey. Travellers to destinations with a high risk for malaria had significantly more accurate risk perceptions (knowledge) than travellers to low-risk destinations. The relative risk for malaria in travellers to high-risk destinations was probably mitigated by higher protection rates against malaria as compared with travellers to low risk destinations. There were no significant differences in intended risk-taking behaviour. Trend analyses showed a significant change over time in attitude towards more risk-avoiding behaviour and towards higher protection rates against malaria in travellers to high-risk destinations. The KAP profile of last-minute travellers substantially increased their relative risk for malaria, which contrasts to the slight increase in relative risk of solo travellers, business travellers and VFRs for malaria. Conclusions: The results of this sequential cohort survey in Dutch travellers suggest an annual 1.8% increase in protection rates against malaria coinciding with an annual 2.5% decrease in intended risk-seeking behaviour. This improvement may reflect the continuous efforts of travel health advice providers to create awareness and to propagate safe and healthy travel. The KAP profile of last-minute travellers, in particular, substantially increased their relative risk for malaria, underlining the continuous need for personal protective measures and malaria chemoprophylaxis for this risk group

Severe leptospirosis in a Dutch traveller returning from the Dominican Republic, October 2011

In October 2011, a case of leptospirosis was identified in a Dutch traveller returning from the Dominican Republic to the Netherlands. The 51-year-old man had aspired muddy water in the Chavón river on 29 September. Twenty days later he presented with fever, nausea, vomiting, diarrhoea, arthralgia, headache, conjunctival suffusion and icterus. Leptospira serovar Icterohaemorrhagiae or Australis infection was confirmed ten days later by laboratory testing

Acquired von Willebrand disease as a cause of recurrent mucocutaneous bleeding in primary thrombocythemia: Relationship with platelet count

We present a 4-year follow-up of a 42-year-old patient with primary thrombocythemia whose clinical course was complicated by two major mucocutaneous bleeding episodes. On both occasions an acquired functional von Willebrand factor deficiency was demonstrated. In contrast to what is reported in the literature, an inverse relationship between platelet number and plasma high-molecular-weight multimers of von Willebrand factor was established