Evaluation of rapid diagnostic tests for malaria in Swedish travellers.

Rapid diagnostic tests (RDTs) for malaria have become valuable tools for the diagnosis of malaria in both endemic and non-endemic areas. During a 7-year period, first the MalaQuick rapid test and then the NOW Malaria test, were evaluated by well-trained laboratory technicians in a university hospital laboratory of parasitology. A total of 635 blood samples were selected from 4731 blood specimens obtained from travellers at the emergency department, at wards and at out-patient clinics. The samples were analysed by microscopy and RDT. Malaria parasites were detected in the blood films of 134 (21%) samples. The sensitivity of the RDT for Plasmodium falciparum was 97.7% (84 of 86 samples) with a negative predictive value of 99.6%. The two false-negative results were associated with low levels of parasitaemia. For non-falciparum species the sensitivity was only 58.3% (28 of 48 samples). Based on the excellent ability of the RDTs to detect P. falciparum infections, we recommend the use of the NOW Malaria test as a complement to microscopy in the laboratory.

Serologic analysis of returned travelers with fever, Sweden.

We studied 1,432 febrile travelers from Sweden who had returned from malaria-endemic areas during March 2005-March 2008. In 383 patients, paired serum samples were blindly analyzed for influenza and 7 other agents. For 21% of 115 patients with fever of unknown origin, serologic analysis showed that influenza was the major cause.

Swedish traveller with Plasmodium knowlesi malaria after visiting Malaysian Borneo.

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 life-threatening 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.

Travellers returning to Sweden with falciparum malaria: pre-travel advice, behaviour, chemoprophylaxis and diagnostic delay.

We have investigated pre-travel advice, behaviour, chemoprophylaxis and diagnostic delay in travellers returning to Sweden with falciparum malaria. Questionnaires were distributed to patients having been notified with falciparum malaria from 1994 to 2001. Of 408 notified patients, 237 (58%) returned the questionnaires; 62% were males and 43% above the age of 45 y. Africa was the travel destination in 90% of the cases, and 27% had travelled to Kenya. 69% had spent more than 1 night in the countryside, and 6% had stayed in modern urban areas only. 40% took an adequate dose of chemoprophylaxis, although this proportion decreased from 55% to 12% during the study period. Nine per cent used both bed nets and mosquito repellents regularly. The median time from onset of symptoms to contact with health care professionals was 2 d, and from that contact to start of malaria treatment the median time was less than 24 h.

Coccidioidomycosis mimicking lung cancer.

A 65-year-old female smoker was admitted due to haemoptysis and a pulmonary infiltrate in the right lower lung lobe. Tumour was suspected, but there was also a history of 2 years spent in Arizona, known to be endemic for the dimorphic fungus Coccidioides immitis. IgG antibodies and airway culture for C. immitis were negative, and surgery was performed for suspected lung cancer. No malignancy was detected at histopathological investigation, but typical coccidioidal spherulae were observed by silver stain. Coccidioidoma may be a differential diagnosis to malignant tumour in individuals visiting endemic areas.

Polyclonal Plasmodium falciparum malaria in travelers and selection of antifolate mutations after proguanil prophylaxis.

The polymorphism of malaria parasites will greatly influence the efficiency of antimalarial drugs and vaccines. This study determined the genetic diversity of Plasmodium falciparum infections in 107 travelers and estimated the importance of mutations in the parasite dihydrofolate reductase (dhfr) gene for clinical breakthrough during proguanil prophylaxis. Genotyping with regards to the three highly polymorphic antigen-coding regions (merozoite surface protein-1 [msp-1], msp-2, and the glutamate-rich protein [glurp]) revealed multiple genotypes (up to five) in 64% of the patients. Single genotype infections were mainly associated with prior intake of antimalarial drugs, but also with a shorter stay in a malaria-endemic area and low parasite density. Malaria breakthrough despite proguanil prophylaxis was always associated with mutations in the dhfr gene; always the Asn-108 mutation and often the Ile-51 and Arg-59 mutations. The Leu-164 mutation was found in four travelers from Africa. Travelers with limited time in an endemic area were often infected with polyclonal P. falciparum infections, which suggests that single mosquito inoculations are often composed of several genetically diverse parasites. Chemoprophylaxis reduces the number of infecting clones and selects for resistant parasites as shown for proguanil through mutations in the dhfr gene.

Cluster of African trypanosomiasis in travelers to Tanzanian national parks.

Game parks in Tanzania have long been considered to be at low risk for African trypanosomiasis; however, nine cases of the disease associated with these parks were recently reported. The outbreak was detected through TropNetEurop, a sentinel surveillance network of clinical sites throughout Europe.