BackgroundBlastocystis sp. are among the most commonly observed intestinal parasites in routine clinical parasitology. Blastocystis in humans consists of at least 9 genetic subtypes. Different subtypes of Blastocystis may be associated with differences in pathogenicity and symptomatology.MethodsAdvanced microscopy on two samples and sequence-confirmed PCR on a third sample from the same individual were used for Blastocystis diagnosis and subtype analyses on routine clinical samples in a university hospital.ResultsWith a combined gold standard of sequence-confirmed PCR and positive advanced microscopy, 107 out of 442 (24.2%) patients were diagnosed with Blastocystis. infection, which is a high frequency of detection in comparison to previous reports from industrialized countries. The sensitivity of microscopy and sequence-confirmed PCR was 99.1% (106/107) and 96.3% (103/107), respectively.Among 103 typable samples, subtype 3 was most abundant (n = 43, 42%), followed by subtypes 1 and 2 (both n = 23, 22%), subtype 4 (n = 12, 12%), and single samples with subtypes 6 (1%) and subtype 7 (1%). The prevalence of Blastocystis infection was 38% in patients from the Department of Tropical Medicine and 18% in patients from other departments.ConclusionsA high prevalence of Blastocystis infection was found with both advanced microscopy and sequence-confirmed PCR in our patient population. Most cases were caused by subtypes ST1, ST2, ST3 and ST4. A significantly higher prevalence was found among patients with a history of recent travel to tropical countries.

b Plasmodium knowlesi infection with low parasitemia presents a diagnostic challenge, as rapid diagnostic tests are often negative and identification to the species level by microscopy is difficult. P. knowlesi malaria in a traveler is described, and real-time PCR is demonstrated to support fast and reliable diagnosis and identification to the species level. CASE REPORT In July 2011, a 32-year-old woman with a blank medical history presented to her general practitioner with complaints of spiking fever with chills, nausea with vomiting, severe headache, and a backache. One day before, she had returned from a 3-week vacation in Malaysia. During the first week of the vacation, she had done a 2-day jungle trek in Borneo, where she had been repeatedly bitten by mosquitoes. Advised by a Dutch travel clinic, she had not used malaria prophylaxis. Three days before her return to The Netherlands, her complaints started. The patient had visited a local doctor and been prescribed ciprofloxacin at 500 mg three times a day and acetaminophen with minimal relief of symptoms.On request of the general practitioner, a malaria diagnosis was performed. The thick blood film was reported dubiously positive, with both a negative thin blood film and a negative antigen test (Binax NOW Malaria, Inverness Medical). Being severely ill, possibly due to malaria, the patient was sent to the first aid department of our hospital for further examination.There, she presented as a sick, hemodynamically stable patient with complaints of fever spiking to 40.2°C. Her physical examination was normal. Laboratory results revealed a normal hemoglobin concentration of 8.4 mmol/liter (reference range, 7.5 to 10.0 mmol/liter), thrombocytopenia at 72 platelets/nl (150 to 400/nl), leukopenia at 3.5 leukocytes/nl (4.0 to 10.0/nl), and a C-reactive protein of level of 190 mg/liter (Ͻ6.0 mg/liter). The total bilirubin level was 12 mol/liter (Ͻ17 mol/liter), the lactate dehydrogenase level was 330 U/liter (Ͻ250 U/liter), the aspartate aminotransferase level was 76 U/liter (Ͻ30 U/liter), the alanine aminotransferase level was 80 U/liter (Ͻ35 U/liter), the alkaline phosphatase level was 65 IU/liter (40 to 120 IU/liter), the ␥-glutamyltransferase level was 66 U/liter (Ͻ40 U/liter), and the prothrombin time was 15.4 s (12 to 14.5 s). Urinalysis was normal.A second malaria test was performed. An antigen test (Binax NOW Malaria) was negative; in both thick and thin blood films, several malaria parasites were observed with a parasite index of 0.0005% (Fig. 1A to C). Although not completely typical, the morphology of the parasites resembled that of Plasmodium malariae. Combining the patient's vacation destination, her severe symptoms, and the morphological resemblance of her parasites to P. malariae, malaria infection with Plasmodium knowlesi was suspected. A blood specimen was sent to a specialized laboratory for molecular diagnosis and correct identification to the species level.The patient was admitted to the hospital. Because the species of the infecting malaria paras...

Ulcerative colitis (UC) is thought to originate from a disbalance in the interplay between the gut microbiota and the innate and adaptive immune system. Apart from the bacterial microbiota, there might be other organisms, such as parasites or viruses, that could play a role in the aetiology of UC. The primary objective of this study was to compare the prevalence of Blastocystis sp. in a cohort of patients with active UC and compare that to the prevalence in healthy controls. We studied patients with active UC confirmed by endoscopy included in a randomised prospective trial on the faecal transplantation for UC. A cohort of healthy subjects who served as donors in randomised trials on faecal transplantation were controls. Healthy subjects did not have gastrointestinal symptoms and were extensively screened for infectious diseases by a screenings questionnaire, extensive serologic assessment for viruses and stool analysis. Potential parasitic infections such as Blastocystis were diagnosed with the triple faeces test (TFT). The prevalence of Blastocystis sp. were compared between groups by Chi-square testing. A total of 168 subjects were included, of whom 45 had active UC [median age 39.0 years, interquartile range (IQR) 32.5–49.0, 49 % male] and 123 were healthy subjects (median age 27 years, IQR 22.0–37.0, 54 % male). Blastocystis sp. was present in the faeces of 40/123 (32.5 %) healthy subjects and 6/45 (13.3 %) UC patients (p = 0.014). Infection with Blastocystis is significantly less frequent in UC patients as compared to healthy controls.

The pathogenic role of the enteric parasite Blastocystis remains controversial. Recent studies have suggested that various subtypes (STs) found in human samples could be correlated to the presence or absence and variability of clinical manifestations, and that STs can differ with respect to drug sensitivity. Polymerase chain reaction (PCR) techniques used to determine these STs are expensive and are usually restricted to research laboratory settings. This study evaluates the potential application of the inexpensive matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) technique to discriminate Blastocystis STs. A database of parasitic protein signatures was constructed for five Blastocystis STs, and the reference spectra were challenged with those from 19 axenic cultures of ST1, ST2, ST3, ST4 and ST8 and those from nine xenic liquid cultures of ST3 and ST4. Samples from axenic cultures were prepared using standard formic acid extraction and direct deposition procedures. The reference spectra revealed five distinct spectral profiles, and the database library allowed for discrimination between all of the cultures with reliability indices ranging from 2.038 to greater than 2.8 when an extraction was performed. The direct deposition procedure resulted in greater variability in the discrimination and direct MALDI-TOF MS identification from xenic liquid cultures was effective in 3 out of 9 samples. MALDI-TOF MS proved to be an effective technology for efficiently discriminating Blastocystis STs in axenic cultures.

This study shows that Blastocystis carriage in travellers is highly dynamic. The observed acquisition and loss of Blastocystis could either be travel-related or reflect the natural course of Blastocystis carriage. We demonstrate that the majority of Blastocystis detected in post-travel samples were already carried before travel.

BackgroundThere is significant need for accurate diagnostic tools for Cryptosporidium spp. and Giardia duodenalis infections in resource limited countries where diarrhoeal disease caused by these parasites is often prevalent. The present study assessed the diagnostic performance of three commercially available rapid diagnostic tests (RDTs) based on faecal-antigen detection for Cryptosporidium spp. and/or G. duodenalis infections in stool samples of children admitted with severe acute malnutrition (SAM) and diarrhoea. An established multiplex PCR was used as reference test.MethodsStool samples from children with SAM and diarrhoea enrolled in a randomized controlled trial (registered at clinicaltrials.gov/ct2/show/NCT02246296) in Malawi (n = 175) and Kenya (n = 120) between December 2014 and December 2015 were analysed by a multiplex PCR for the presence of Cryptosporidium spp., G. duodenalis or Entamoeba histolytica parasite DNA. Cryptosporidium-positive samples were species typed using restriction fragment length polymorphism analysis. A sub-sample of the stool specimens (n = 236) was used for testing with three different RDTs. Diagnostic accuracy of the tests under evaluation was assessed using the results of PCR as reference standard using MedCalc software. Pearson Chi-square test and Fisher’s exact test were used to determine (significant) difference between the number of cryptosporidiosis or giardiasis cases found by PCR in Malawi and Kenya. The overall diagnostic accuracy of each RDT was calculated by plotting a receiver operating characteristic (ROC) curve for each test and to determine the area under the curve (AUC) using SPSS8 software.ResultsPrevalence of Cryptosporidium spp. by PCR was 20.0 and 21.7% in Malawi and Kenya respectively, mostly C. hominis. G. duodenalis prevalence was 23.4 and 5.8% in Malawi and Kenya respectively. E. histolytica was not detected by PCR. RDT testing followed the same pattern of prevalence. RDT sensitivities ranged for cryptosporidiosis from 42.9 to 76.9% and for G. duodenalis from 48.2 to 85.7%. RDT specificities ranged from 88.4 to 100% for Cryptosporidium spp. and from 91.2 to 99.2% for G. duodenalis infections. Based on the estimated area under the curve (AUC) values, all tests under evaluation had an acceptable overall diagnostic accuracy (> 0.7), with the exception of one RDT for Cryptosporidium spp. in Malawi.ConclusionsAll three RDTs for Cryptosporidium spp. and Giardia duodenalis evaluated in this study have a moderate sensitivity, but sufficient specificity. The main value of the RDTs is within their rapidness and their usefulness as screening assays in surveys for diarrhoea.

A 54-year-old woman presented with 2 weeks of fever after a trip to the Northeastern United States. Except for an erythematous skin lesion on her right shoulder, no physical abnormality was detected. We diagnosed concomitant borreliosis and babesiosis. Both infections were possibly acquired by one bite from Ixodes scapularis.

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