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Biomedical subjects

M P Grobusch

Publications and source records attributed to M P Grobusch.

At least 37 records · Page 2Linked to original sources

Patterns of Plasmodium falciparum drug resistance in nonimmune travellers to Africa.

Falciparum malaria is a major cause of morbidity and mortality among tourists returning from endemic areas. Treatment of infected travellers is frequently standardised, and resistance tests are rarely done as they are difficult to perform and interpret. In vitro tests of resistance to chloroquine, mefloquine, quinine, halofantrine, tetracycline, and sulfadoxine/pyrimethamine were performed on Plasmodium falciparum isolates obtained from 52 German travellers returning from malarious areas in sub-Saharan Africa. All patients were treated successfully with a standard dose of mefloquine. No in vivo resistance was observed. Although 20 (38.5%) isolates showed no signs of in vitro resistance, the remaining 32 (61.5%) were resistant to at least one of the tested antimalarial agents. Of these 32 isolates, 11 were multiresistant. Resistance to chloroquine was most frequently observed (55.8%), followed by sulfadoxine/pyrimethamine (11.5%), mefloquine (9.6%), quinine (3.8%), and halofantrine (1.9%). In vitro resistance to tetracycline was not detected in this study group. Treatment of falciparum malaria without resistance testing appears to be effective in most cases, but possible therapeutic failure due to emerging drug resistance should be kept in mind.

Adolescent↗

A case of gnathostomiasis in a European traveller returning from Mexico.

Hundreds of human cases of gnathostomiasis have recently been reported from Mexico, where the disease is becoming a public health problem. We report a case of gnathostomiasis in a French tourist returning from Mexico. Tourists travelling in endemic countries are at risk of gnathostomiasis and should be advised about the risks of eating raw fish as a suspected source of infection.

Adult↗

Evaluation of a dipstick test for the rapid diagnosis of imported malaria among patients presenting within the network TropNetEurop.

Lack of experience on the part of involved laboratory personnel frequently complicates swift diagnosis of imported falciparum malaria in non-endemic areas. Diagnostic tools based on the dipstick principle for the detection of plasmodial histidine-rich protein 2 have been marketed for several years and have been extensively evaluated. Recently, a test kit capable of detecting antigen of Plasmodium falciparum and P. vivax has been introduced. In order to evaluate this newly available tool, specimens from 664 patients were screened during the course of a prospective multicentre study within the European Network on Imported Infectious Disease Surveillance (TropNetEurop). Among the screened specimens, samples from 82 patients (12.3%) were positive for falciparum malaria using expert microscopy. A further 17 samples were positive for vivax malaria. The evaluated test kit performed with a sensitivity of 87.8% and a specificity of 99% for detection of falciparum malaria. Respective values for vivax malaria were 76.5% and 100%. Dipstick tests have the potential of improving the speed and accuracy of the diagnosis of falciparum malaria, especially if non-specialized laboratories are involved. However, decreased values of sensitivity and specificity, in comparison with expert microscopy, still impose a clear limit on the usefulness of the currently available kits.

Antibodies, Protozoan↗

Automated malaria diagnosis using pigment detection.

Several new methods of malaria diagnosis have recently been developed, but these all rely on clinical suspicion and, consequently, an explicit clinical request. Although some methods lend themselves to automation (eg. PCR), no technique can yet be used for routine clinical automated screening. Detection of birefringent haemozoin has been used to diagnose malaria since the turn of the 20th century. A new generation of full blood count analysers, used widely in clinical laboratories, have the potential to detect haemozoin in white blood cells and probably erythrocytes. Thomas Hänscheid, Emilia Valadas and Martin Grobusch here describe this novel technique for malaria diagnosis and discuss its potential applications.

Blood Cell Count↗

Cutaneous gnathostomiasis in a woman from Bangladesh.

A woman from Bangladesh who had lived in Germany for more than 2 years presented with migratory, painful swellings on her left hand and arm of 5 months duration. Laboratory examinations yielded a marked eosinophilia and a grossly elevated IgE level in combination with an inflammatory reaction restricted to the subcutaneous tissues. A preliminary diagnosis of gnathostomiasis was established and confirmed by a positive gnathostoma serology by enzyme immunoassay (EIA). Treatment was initiated with albendazole, leading to the outward migration of a larva and complete resolution of clinical disease. Currently, there is no definitive therapy that has been proved to be both safe and highly effective. A wide range of potential agents has been used in clinical studies, but only albendazole has proved to be reliably effective to date, stimulating the outward migration of larvae in a proportion of cases of cutaneous disease, as observed in the present case.

Adult↗

Malaria diagnosis with the haematology analyser Cell-Dyn 3500: What does the instrument detect?

The Cell-Dyn 3500 instrument could become a sensitive and specific tool in the diagnosis of malaria. The instrument appears to detect malaria-pigment within monocytes and granulocytes. A case of P. vivax malaria in a patient with increased osmotically resistant erythrocytes illustrates the potential of the instrument to detect intraerythrocytic parasites with pigment. However, in most malaria-patients with normal red cell osmotic resistance the observed phenomena seem rather to represent intraleukocytic pigment. This can remain in the circulation of clinically and parasitologically cured individuals and thus may not indicate acute infection. While the instrument can indicate those patients who have been infected a diagnosis of acute malaria must be established independently.

Animals↗

Acute fascioliasis with multiple liver abscesses.

Human fascioliasis is distributed worldwide with several foci of high endemicity. Being a rare disease in Europe, we describe here a case in the initial hepatic phase of the disease. Therapeutic and, with reference to the 2 distinct stages of disease, diagnostic standards are discussed.

Acute Disease↗

Self-use of rapid tests for malaria diagnosis by tourists.

In a survey among febrile European tourists in Kenya, only 68% were able to carry out immunochromatographic dipstick tests for detection of Plasmodium falciparum antigen correctly, and ten of 11 with malaria failed to diagnose themselves correctly. Rapid tests for self-diagnosis by tourists cannot be recommended without appropriate training before departure.

Female↗

High recombination rate in natural populations of Plasmodium falciparum.

Malaria parasites are sexually reproducing protozoa, although the extent of effective meiotic recombination in natural populations has been debated. If meiotic recombination occurs frequently, compared with point mutation and mitotic rearrangement, linkage disequilibrium between polymorphic sites is expected to decline with increasing distance along a chromosome. The rate of this decline should be proportional to the effective meiotic recombination rate in the population. Multiple polymorphic sites covering a 5-kb region of chromosome 9 (the msp1 gene) have been typed in 547 isolates from six populations in Africa to test for such a decline and estimate its rate in populations of Plasmodium falciparum. The magnitude of two-site linkage disequilibrium declines markedly with increasing molecular map distance between the sites, reaching nonsignificant levels within a map range of 0.3-1.0 kb in five of the populations and over a larger map distance in the population with lowest malaria endemicity. The rate of decline in linkage disequilibrium over molecular map distance is at least as rapid as that observed in most chromosomal regions of other sexually reproducing eukaryotes, such as humans and Drosophila. These results are consistent with the effective recombination rate expected in natural populations of P. falciparum, predicted on the basis of the underlying molecular rate of meiotic crossover and the coefficient of inbreeding caused by self-fertilization events. This is conclusive evidence to reject any hypothesis of clonality or low rate of meiotic recombination in P. falciparum populations. Moreover, the data have major implications for the design and interpretation of population genetic studies of selection on P. falciparum genes.

Africa↗

Sensitivity and specificity of dipstick tests for rapid diagnosis of malaria in nonimmune travelers.

Swift diagnosis of Plasmodium falciparum malaria in areas where the disease is not endemic is frequently complicated by the lack of experience on the side of involved laboratory personal. Diagnostic tools based on the dipstick principle for the detection of plasmodial histidine-rich protein 2 (HRP-2) and parasite-specific lactate dehydrogenase (pLDH), respectively, have become available for the qualitative detection of P. falciparum malaria. In order to evaluate two of the currently available assays, specimens from 231 patients were screened during a prospective multicenter study. Among the screened specimens, samples from 53 patients (22.9%) were positive for P. falciparum malaria by microscopy and/or PCR. While the test kit based on the detection of HRP-2 performed with a sensitivity of 92.5% and a specificity of 98.3%, the kit for the detection of pLDH showed a sensitivity of 88.5% and a specificity of 99.4%. Dipstick tests have the potential of enhancing speed and accuracy of the diagnosis of P. falciparum malaria, especially if nonspecialized laboratories are involved.

Biomarkers↗