Artemether-lumefantrine, mefloquine and atovaquone-proguanil in the treatment of uncomplicated Plasmodium falciparum malaria in travellers: A retrospective comparative study of efficacy and treatment failures.

BACKGROUND: The aim of this study was to evaluate the rates of parasitaemia clearance and the prevalence of treatment failure in patients with uncomplicated Plasmodium falciparum malaria treated with artemether-lumefantrine (AL), mefloquine (MQ), and atovaquone-proguanil (AP). METHOD: The retrospective descriptive study included adult patients with uncomplicated P. falciparum malaria treated at the University Hospital Bulovka in Prague from 2006 to 2019. Parasitaemia clearance was estimated using a linear regression model. RESULTS: The study included 72 patients with a median age of 33 years (IQR 27-45) and a male to female ratio of 3.2:1. Thirty-six patients (50.0%) were treated with AL, 27 (37.5%) with MQ and 9 (12.5%) with AP. The proportion of VFR and migrants was 22.2% with no significant differences among the three groups. The median time to the parasitaemia clearance was two days (IQR 2-3) in patients treated with AL versus four days in the MQ (IQR 3-4) and AP (IQR 3-4) groups, p < 0.001. The clearance rate constant was 3.3/hour (IQR 2.5-4.0) for AL, 1.6/hour (IQR 1.3-1.9) for MQ, and 1.9/hour (IQR 1.3-2.4) for AP, p < 0.001. Malaria recrudescence occurred in 5/36 (13.9%) patients treated with AL and in no patients treated with MQ or AP. CONCLUSIONS: The findings demonstrate the superior efficacy of AL compared to other oral antimalarials in early malaria treatment. However, we observed a higher rate of late treatment failure in patients treated with AL than previously reported. This issue warrants further investigation of possible dose adjustments, extended regimens, or alternative artemisinin-based combinations.

Epidemiology and clinical features of imported malaria: a 14-year retrospective single-centre descriptive study in Prague, Czech Republic.

BACKGROUND: Malaria represents one of the most important imported tropical infectious diseases in European travellers. The objective of the study was to identify changes in the epidemiological features of imported malaria and to analyse the clinical findings and outcomes of imported malaria. METHODS: This single-centre descriptive study retrospectively analysed the medical records of all imported malaria cases in travellers treated at the Department of Infectious Diseases of University Hospital Bulovka in Prague from 2006 to 2019. RESULTS: The study included 203 patients with a median age of 37 years (IQR 30-48) and a male to female ratio of 3.72:1. Plasmodium falciparum was the predominant species (149/203), and its proportion significantly increased from 35/60 cases (58.3%) in 2006-2011 to 69/80 (86.3%) in 2016-2019 (p < 0.001). In contrast, the incidence of Plasmodium vivax malaria decreased from 19/60 cases (31.7%) in 2006-2011 to 5/80 (6.3%) in 2016-2019 (p < 0.001). Malaria was imported from sub-Saharan Africa in 161/203 cases (79.3%). The proportion of travellers from Southeast and South Asia decreased from 16/60 (26.7%) and 6/60 (10.0%) in 2006-2011 to 2/80 (2.5%) and no cases (0.0%) in 2016-2019, respectively (p < 0.001 and p = 0.006). Tourism was the most common reason for travel (82/203), however, the proportion of non-tourists significantly increased over time from 29/60 (48.3%) in 2006-2011 to 55/80 (68.8%) in 2016-2019, p = 0.015. Severe malaria developed in 32/203 (15.8%) patients who were significantly older (p = 0.013) and whose treatment was delayed (p < 0.001). Two lethal outcomes were observed during the study period. CONCLUSIONS: This study demonstrated a significant increase in P. falciparum malaria, which frequently resulted in severe disease, especially in older patients and those with delayed treatment initiation. The rising proportion of imported malaria in non-tourists, including business travellers and those visiting friends and relatives, is another characteristic finding analogous to the trends observed in Western European and North American centres. The described changes in the aetiology and epidemiology of imported malaria may serve to optimize pre-travel consultation practices and improve post-travel diagnostics and medical care.

A case of amoebic colitis with Crohn-like endoscopic and histopathological features.

Amoebic colitis represents a common parasitic infection in developing countries. In western world, it is encountered only sporadically. The clinical presentation is usually non-specific, non-invasive laboratory tests are often false negative and endoscopic and histopathological appearance may mimic other illnesses, especially Crohns disease. The disease therefore harbours a huge risk of misdiagnosing and a proper diagnosis is usually challenging. We present a case of an amoebic colitis with Crohn-like features and negative parasitological testing in a 53-years-old woman, in which the final diagnosis was established on the basis of its histopathological examination.

[The first case of scrub typhus diagnosed in a Czech traveler].

This case report describes the first case of imported scrub typhus in a Czech traveler. The infection was diagnosed in a 38-year-old male traveler returning from a one-week business/tourist trip to Laos who presented with fever, chills, joint and muscle pain, localized inguinal lymphadenopathy, rash and a typical eschar. Although laboratory findings included elevation of CRP, hepatic aminotransferases and lactate dehydrogenase, complete blood count revealed only borderline leukocytosis with mild thrombocytopenia. The diagnosis of scrub typhus was made by serological detection of specific antibodies. The patient was treated with a 200 mg daily dose of oral doxycycline for 20 days. His clinical course was uncomplicated. The case underpins the need for a broader differential diagnosis in patients with travel-related health problems, especially those presenting with fever and rash, including less common or neglected tropical diseases.

Characterisation of Species and Diversity of Anopheles gambiae Keele Colony.

Anopheles gambiae sensu stricto was recently reclassified as two species, An. coluzzii and An. gambiae s.s., in wild-caught mosquitoes, on the basis of the molecular form, denoted M or S, of a marker on the X chromosome. The An. gambiae Keele line is an outbred laboratory colony strain that was developed around 12 years ago by crosses between mosquitoes from 4 existing An. gambiae colonies. Laboratory colonies of mosquitoes often have limited genetic diversity because of small starting populations (founder effect) and subsequent fluctuations in colony size. Here we describe the characterisation of the chromosomal form(s) present in the Keele line, and investigate the diversity present in the colony using microsatellite markers on chromosome 3. We also characterise the large 2La inversion on chromosome 2. The results indicate that only the M-form of the chromosome X marker is present in the Keele colony, which was unexpected given that 3 of the 4 parent colonies were probably S-form. Levels of diversity were relatively high, as indicated by a mean number of microsatellite alleles of 6.25 across 4 microsatellites, in at least 25 mosquitoes. Both karyotypes of the inversion on chromosome 2 (2La/2L+a) were found to be present at approximately equal proportions. The Keele colony has a mixed M- and S-form origin, and in common with the PEST strain, we propose continuing to denote it as an An. gambiae s.s. line.

DEAD-box RNA helicase is dispensable for mitochondrial translation in Trypanosoma brucei.

DEAD-box RNA helicase, a putative subunit of the mitochondrial ribosome of Trypanosoma brucei, has been down-regulated in the procyclic and bloodstream stage by RNA interference. Although ablation of the transcript leads to a week growth phenotype in the procyclic cells, the protein does not seem to be essential for mitochondrial translation under standard cultivation conditions, as shown by an assay that allows visualization of the de novo synthesized proteins. Furthermore, we show that synthesis of cytochrome c oxidase subunit I and cytochrome b does not occur in the mitochondrion of the bloodstream stage.