SUMMARYThe protective efficacy of BCG vaccination against pulmonary tuberculosis (TB) is highly variable in different populations. The reason remains to be elucidated. This study aims to investigate the possible effect of intestinal helminths on the immune response to PPD in naturally immunized or BCGvaccinated humans. The study population was assessed for helminthic infection and those found to be positive were randomly assigned to either an albendazole treatment group or a control group who received a placebo. The immune response to PPD was compared between the two groups. In addition, subjects who were tuberculin skin test-negative in both groups were BCG vaccinated and later on tested for PPD-specific responses. Albendazole induced elimination/or reduction in intestinal worms resulting in a significant improvement in T cell proliferation and in interferon-gamma production by peripheral blood mononuclear cells (PBMC) stimulated with PPD. Moreover, BCG vaccination significantly improved PPD-specific immune responses in the treated group but not in the placebo group. The differences in the in vivo skin test responses were not significant. The data show that cellular immune responses to PPD are reduced in persons with concurrent helminthic infections, perhaps reflecting a lowered resistance to mycobacterial infections. This could explain, at least in part, the reduced efficacy of BCG against TB in helminth-endemic areas of the world.

Travelers have the potential both to acquire and to spread dengue virus infection. The incidence of dengue fever (DF) among European travelers certainly is underestimated, because few centers use standardized diagnostic procedures for febrile patients. In addition, DF is currently not reported in most European public health systems. Surveillance has commenced within the framework of a European Network on Imported Infectious Disease Surveillance (TropNetEurop) to gain information on the quantity and severity of cases of dengue imported into Europe. Descriptions of 294 patients with DF were analyzed for epidemiological information and clinical features. By far the most infections were imported from Asia, which suggests a high risk of DF for travelers to that region. Dengue hemorrhagic fever occurred in 7 patients (2.4%) all of whom recovered. Data reported by member sites of the TropNetEurop can contribute to understanding the epidemiology and clinical characteristics of imported DF.

Plasmodium knowlesi is typically found in nature in macaques and has recently been recognized as the fifth species of Plasmodium causing malaria in human populations in south-east Asia. A case of knowlesi malaria is described in a Swedish man, who became ill after returning from a short visit to Malaysian Borneo in October 2006. His P. knowlesi infection was not detected using a rapid diagnostic test for malaria, but was confirmed by PCR and molecular characterization. He responded rapidly to treatment with mefloquine. Evaluation of rapid diagnostic kits with further samples from knowlesi malaria patients are necessary, since early identification and appropriate anti-malarial treatment of suspected cases are essential due to the rapid growth and potentially lifethreatening nature of P. knowlesi. Physicians should be aware that knowlesi infection is an important differential diagnosis in febrile travellers, with a recent travel history to forested areas in south-east Asia, including short-term travellers who tested negative with rapid diagnostic tests.