A. Van Gompel

Evaluation of two tests based on the detection of histidine rich protein 2 for the diagnosis of imported Plasmodium falciparum malaria.

The ParaSight-F dipstick test (Becton Dickinson, USA) and the ICT Malaria Pf test (ICT, Australia) both detect histidine rich protein 2 (HRP-2), a water-soluble antigen expressed by Plasmodium falciparum trophozoites. The present study compared the diagnostic performance of both tests in persons returning to Belgium from countries endemic for malaria. During a period of 18 months both tests were performed on all patients returning from the tropics with a positive malaria blood film. Patients with fever without an obvious cause were used as controls. For the ParaSight-F test, considering P. falciparum trophozoites only, sensitivity was 95% and specificity 90%. Considering trophozoites of all species of Plasmodium, sensitivity was 71% and specificity 87%. Finally, considering patients with clinical malaria, the sensitivity of the test was 72% and specificity 87%. For the ICT Malaria Pf test, sensitivity was 95% and specificity 89% for P. falciparum trophozoites only, 71% and 86% for trophozoites of all species, and 72% and 87% for clinical malaria. Both tests gave highly comparable results. However, antigen detection assays cannot replace conventional microscopy in diagnosing imported malaria. Thick blood film examination is more sensitive and more specific, it allows estimation of parasitaemia and distinction between parasite growth stages, and it covers all species. Moreover, with treated patients the use of antigen tests might lead to problems in determining the efficacy of therapy.

Heat-shock protein 70 gene sequencing for Leishmania species typing in European tropical infectious disease clinics

We describe Leishmania species determination on clinical samples on the basis of partial sequencing of the heat-shock protein 70 gene (hsp70), without the need for parasite isolation. The method is especially suited for use in non-endemic infectious disease clinics dealing with relatively few cases on an annual basis, for which no fast high throughput diagnostic tests are needed. We show that the results obtained from this gene are in nearly perfect agreement with those from multilocus enzyme electrophoresis, which is still considered by many clinicians and the World Health Organization (WHO) as the gold standard in Leishmania species typing. Currently, 203 sequences are available that cover the entire hsp70 gene region analysed here, originating from a total of 41 leishmaniasis endemic countries, and representing 15 species and sub-species causing human disease. We also provide a detailed laboratory protocol that includes a step-by-step procedure of the typing methodology, to facilitate implementation in diagnostic laboratories.

A Belgian traveler who acquired yellow fever in the Gambia.

A 47-year-old Belgian woman acquired yellow fever during a 1-week vacation in The Gambia; she had never been vaccinated against yellow fever. She died of massive gastrointestinal bleeding 7 days after the onset of the first symptoms. This dramatic case demonstrates that it is important for persons to be vaccinated against yellow fever before they travel to countries where yellow fever is endemic, even if the country, like The Gambia, does not require travelers to be vaccinated.

Hyperreactive malaria in expatriates returning from sub-Saharan Africa

Summary The extreme presentation of hyperreactive malaria is hyperreactive malarial splenomegaly syndrome (HMS). Some patients present with a less pronounced syndrome. To investigate whether the degree of splenomegaly correlates with the degree of immune stimulation, whether prophylaxis or recent treatment play a role, and whether short therapy alone is effective, we examined retrospectively the medical records of expatriates with exposure to P. falciparum who attended our outpatient department from 1986 to 1997, particularly subacute symptoms or signs, strongly elevated malarial antibodies and elevated total serum IgM. We analysed duration of stay, prophlyaxis intake, spleen size, serum IgM levels and response to antimalarial treatment. Serum IgM levels were significantly higher in patients with larger splenomegaly. The use of chloroquine alone as treatment for presumptive or proved malaria attacks was correlated with larger spleen size. Short adequate antimalarial therapy resulted in marked improvement or complete recovery. In nine patients the hyperreactive response reappeared after re‐exposure, in four of them twice. We conclude that patients with subacute symptoms but without gross splenomegaly may have very high levels of IgM and malarial antibodies, and relapse on re‐exposure, suggesting the existence of a variant of the hyperreactive malarial splenomegaly syndrome without gross splenomegaly.

Selective ambulatory management of imported falciparum malaria: a 5-year prospective study

The ambulatory management of imported Plasmodium falciparum malaria is controversial because criteria for safe selection of patients are imprecise. The aim of the present study was to investigate the evolution and outcome of patients diagnosed with Plasmodium falciparum malaria at a Belgian referral institute in order to assess the safety of the institute’s current selective ambulatory management protocol. From 2000 to 2005, all patients diagnosed with P. falciparum infection at the Institute of Tropical Medicine and the University Hospital of Antwerp were enrolled prospectively. Ambulatory treatment was offered to nonvomiting patients if they exhibited none of the 2000 World Health Organization criteria of severity and had parasitemia below 1% at the initial assessment. The treatment of choice was quinine (plus doxycycline or clindamycin) for inpatients and atovaquone-proguanil for outpatients. P. falciparum malaria was diagnosed in 387 patients, of whom 246 (64%) were Western travelers or expatriates and 117 (30%) were already on antimalarial therapy. At diagnosis, 60 (15%) patients had severe malaria. Vital organ dysfunction was initially seen in 34 and developed later in five others. Five patients died. Of the 327 patients initially assessed as having uncomplicated malaria, 113 (35%) were admitted immediately; of these, 4 developed parasitemia ≥5% at a later stage but without any clinical consequence. None of the 214 individuals initially treated as outpatients experienced any malaria-related complications, including 10 who were admitted later. Vital organ dysfunction was observed in only 2 of the 214 patients with initial parasitemia <1% who had not taken antimalarial agents (both patients had impaired consciousness at presentation). Ambulatory treatment is safe in treatment-naive malaria patients with parasitemia <1% who do not vomit and who do not exhibit any criteria of severe malaria.

EPIDEMIOLOGY AND OUTCOME OF SHIGELLA, SALMONELLA AND CAMPYLOBACTER INFECTIONS IN TRAVELLERS RETURNING FROM THE TROPICS WITH FEVER AND DIARRHOEA

Abstract Introduction: During a study on fever after a stay in the tropics, we aimed at investigating the epidemiology and outcome of invasive bacterial enteritis due to Shigella, Salmonella or Campylobacter spp. in patients diagnosed with febrile traveller’s diarrhoea. Methods: From April 2000 to September 2006, we evaluated prospectively 594 travellers presenting with fever and diarrhoea within a month after a stay in the tropics. Patients not found with a systemic infection were assumed to have febrile traveller’s diarrhoea (TD). Invasive bacterial enteritis was confirmed by isolation of Shigella, Campylobacter or nontyphoidal Salmonella in stool cultures. Results: Systemic infections (mainly malaria) were diagnosed in 259 (44%) evaluated travellers. Invasive bacterial enteritis, either alone or with another infection, was confirmed in 114 (34%) of the 335 remaining patients with febrile TD. Aetiologies were distributed between Campylobacter jejuni (47, 41%), Shigella spp. (43, 38%), Salmonella spp. (22, 19%) and mixed Campylobacter-Salmonella infection (2, 2%). Invasive bacterial enteritis accounted for about a third of febrile TD cases occurring after a stay in sub-Saharan Africa, North Africa/Middle East or Latin America, and for half of those occurring after a travel to southern Asia (including 33% only due to C. jejuni). Resistance to fluoroquinolones was exclusively observed in C. jejuni isolates, but at an overall rate of 53%. Clinical failure occurred in 33% of the patients with C. jejuni infection empirically treated with a fluoroquinolone. Conclusion: Invasive bacterial enteritis was a frequent aetiology of febrile TD. C. jejuni was the leading pathogen after a travel to southern Asia, and was associated with high rate of resistance to fluoroquinolones and of clinical failure.

Kabisa: an interactive computer-assisted training program for tropical diseases

In Europe, tropical pathology is usually taught in special short courses, intended for those planning to practise in developing countries. The theoretical knowledge to be assimilated during this short period is considerable, and turning such newly acquired knowledge into competence is difficult.

Chikungunya virus and West Nile virus infections imported into Belgium, 2007–2012

Arboviral infections are emerging among tourists travelling to (sub)tropical regions. This study aims to describe the importation of chikungunya virus (CHIKV) and West Nile virus (WNV) into Belgium over a 6-year period from 2007 to 2012. Clinical samples were obtained from travellers presenting at the outpatient clinic of the Institute of Tropical Medicine (ITM), Antwerp, Belgium or submitted to the Central Laboratory for Clinical Biology of the ITM. Testing was performed by serology and/or by real-time reverse transcriptase-polymerase chain reaction. A total of 1288 returning travellers were investigated for CHIKV infection resulting in 34 confirmed and two probable diagnoses (2·80%). Out of 899 patients, four confirmed and one probable imported WNV infections were diagnosed (0·55%). No locally acquired cases have been registered in Belgium until now and the geographical origin of the imported infections reflects the global locations where the viruses are circulating.

The hypereosinophilic syndrome after residence in a tropical country: report of 4 cases

Abstract Severe eosinophilia may be complicated by acute or chronic visceral damage. The underlying origin of the hypereosinophilia may be infectious, allergic, toxic, malignant or systemic (the secondary or reactive hypereosinophilie syndrome), but in a number of cases no cause can be found (the idiopathic hypereosinophilie syndrome). We describe 4 cases with hypereosinophilia and sec-ondary visceral damage after residence in a tropical region. In three cases a helminthic infection was the obvious cause, the brain and the heart were the target organs. After treatment of the infection both the hypereosinophilia and the neurological and cardiac lesions disappeared. The fourth patient died of multiorgan disease. No definite trigger of the hypereosinophilia could be found. We discuss clinical findings, necessary investigations and therapeutic strategies.

FEVER AFTER A STAY IN THE TROPICS Part 2 : common imported tropical diseases

Since world-wide travel and migration increased considerably in the last decades, physicians of industrialised countries may face various travel-related health problems or infectious diseases coming from all regions of the world. In 1997, about 650000 Belgian travellers had visited tropical and subtropical regions (1). After a short-term visit to developing countries, 15 % of 7886 Swiss travellers reported health problems, abroad or upon return, and 8 % consulted a doctor (2). In another study, up to 64 % of 784 American travellers experienced some illness during or after their travel, and febrile episodes were reported by 13 % of them (3). In travel clinics, fever represents the second cause of posttravel consultation after diarrhoea and has been reported by 20-37% of sick travellers in 2 observational studies (4,5). The diagnostic approach of fever in travellers usually challenges the attending clinician. First, the possible exposure to tropical pathogens broadens widely the differential diagnosis. In addition, fever and associated symptoms may not be specific enough to allow early diagnosis, or at least early distinction between a minor, self-limited process and a progressive, potentially lifethreatening illness. Finally, physicians of European countries may be unfamiliar with tropical infections that the patient may have encountered while travelling. As the possible causes of imported febrile illnesses are numerous and potentially severe, the clinician needs a logical approach in order to establish promptly an etiologic diagnosis. This article (part 1) describes the prevalence of the different illnesses reported in recent observational studies among travellers returning from the tropics, and discusses the required diagnostic work up for such patients. The second article (part 2) provides an updated knowledge of the most common tropical infections.