The imperative for quality control programs in Monkeypox virus DNA testing by PCR: CIBERINFEC quality control.

To evaluate molecular assays for Mpox diagnosis available in various clinical microbiology services in Spain through a quality control (QC) approach. A total of 14 centers from across Spain participated in the study. The Reference Laboratory dispatched eight serum samples and eight nucleic acid extracts to each participating center. Some samples were spiked with Mpox or Vaccinia virus to mimic positive samples for Mpox or other orthopox viruses. Participating centers provided information on the results obtained, as well as the laboratory methods used. Among the 14 participating centers seven different commercial assays were employed, with the most commonly used kit being LightMix Modular Orthopox/Monkeypox (Mpox) Virus (Roche®). Of the 12 centers conducting Mpox determinations, concordance ranged from 62.5% (n = 1) to 100% (n = 11) for eluates and from 75.0% (n = 1) to 100% (n = 10) for serum. Among the 10 centers performing Orthopoxvirus determinations, a 100% concordance was observed for eluates, while for serum, concordance ranged from 87.5% (n = 6) to 100% (n = 4). Repeatedly, 6 different centers reported a false negative in serum samples for Orthopoxvirus diagnosis, particularly in a sample with borderline Ct = 39. Conversely, one center, using the TaqMan™ Mpox Virus Microbe Detection Assay (Thermo Fisher), reported false positives in Mpox diagnosis for samples spiked with vaccinia virus due to cross-reactions. We observed a positive correlation of various diagnostic assays for Mpox used by the participating centers with the reference values. Our results highlight the significance of standardization, validation, and ongoing QC in the microbiological diagnosis of infectious diseases, which might be particularly relevant for emerging viruses.

Clinical evaluation of BioFire® multiplex-PCR panel for acute undifferentiated febrile illnesses in travellers: a prospective multicentre study.

BACKGROUND: Identifying the causes of Acute Undifferentiated Febrile Illness (AUFI) is key to improve the management of returning travellers with fever. We evaluated a BioFire®FilmArray® prototype panel of multiplex nucleic acid amplification tests (NAAT) targeting different relevant pathogens in travellers returning with fever. METHODS: Prospective, multicentre study to evaluate a prototype panel in whole blood samples of adult international travellers presenting with AUFI in three European travel Clinics/Hospitals (November 2017-November 2019). We evaluated 15 target analytes: Plasmodium spp., Plasmodium falciparum, Plasmodium knowlesi, Plasmodium malariae, Plasmodium ovale, Plasmodium vivax, chikungunya virus, dengue virus, Zika virus, Anaplasma phagocytophilum, Borrelia spp., Leptospira spp., Orientia tsutsugamushi, Rickettsia spp. and Salmonella spp. Results were compared with composite reference standards (CRSs) for each target infection, including direct methods [smear microscopy, rapid diagnostic test (RDT), reference NAAT and blood cultures] and indirect methods (paired serology). FINDINGS: Among 455 travellers with AUFI, 229 target infections were diagnosed; the prototype panel detected 143 (overall sensitivity and specificity of 62.5 and 99.8%, respectively). The panel identified all Plasmodium infections (n = 82). Sensitivity for dengue (n = 71) was 92.9, 80.8 and 68.5% compared with RDT, NAAT and CRS, respectively. Compared with direct methods and CRS, respectively, the prototype panel detected 4/4 and 4/6 chikungunya, 2/2 and 4/29 Leptospira spp., 1/1 and 1/6 O. tsutsugamushi and 2/2 and 2/55 Rickettsia spp., but 0/2 and 0/10 Zika, 0/1 and 0/11 A. phagocytophylum and 0/3 Borrelia spp. diagnosed by serology and only 1/7 Salmonella spp. diagnosed by blood cultures. 77/86 (89.5%) infections not detected by the panel were diagnosed by serology. INTERPRETATION: The prototype panel allowed rapid and reliable diagnosis for malaria, dengue and chikungunya. Further improvements are needed to improve its sensitivity for Zika and important travel-related bacterial infections.

Doxycycline responding illnesses in returning travellers with undifferentiated non-malaria fever: a European multicentre prospective cohort study.

BACKGROUND: Diagnosis of undifferentiated non-malaria fevers (NMF) in returning travellers is a great challenge. Currently, there is no consensus about the use of empirical antibiotics in returning travellers with undifferentiated NMF. Although studies in endemic areas showed that a wide range of pathogens implicated in undifferentiated NMF are treatable with doxycycline, the role of doxycycline in returning travellers with fever still has to be explored. METHODS: Prospective European multicentre cohort study of febrile international travellers (November 2017-November 2019). Immunological and molecular diagnostic techniques for doxycycline responding illnesses (DRI) agents such as Anaplasma phagocytophilum, spotted fever group Rickettsia spp., typhus group Rickettsia spp., Coxiella burnetii, Bartonella spp., Orientia tsutsugamushi, Borrelia miyamotoi, Borrelia recurrentis and Leptospira spp. were systematically performed in all patients with undifferentiated NMF. We estimated the prevalence and predictive factors of DRI in returning travellers with undifferentiated NMF. RESULTS: Among 347 travellers with undifferentiated NMF, 106 (30·5%) were finally diagnosed with DRI. Only 57 (53·8%) of the 106 DRI infections were diagnosed by the standard of care. The main causes of DRI were: 55 (51·9%) Rickettsia spp., 16 (15·1%) C. burnetii; 15 (14·2%) Bartonella spp.; 13 (12·3%) Leptospira spp. and 10 (9·5%) A. phagocytophilum. The only predictive factor associated with DRI was presenting an eschar (aOR 39·52, 95%CI 4·85-322·18). Features of dengue such as retro-orbital pain (aOR 0·40, 95%CI 0·21-0·76) and neutropenia (aOR 0·41, 95%CI 0·21-0·79) were negatively associated with DRI. CONCLUSIONS: Although DRI are responsible for 30% of undifferentiated NMF cases in travellers, those are seldom recognized during the first clinical encounter. Empirical treatment with doxycycline should be considered in returning travellers with undifferentiated fever and negative tests for malaria and dengue, particularly when presenting severe illness, predictive factors for rickettsiosis or no features of dengue.

Diagnostic Performance of Six Rapid Antigen Tests for SARS-CoV-2.

Microbiological diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been a challenge. Although real-time reverse transcription PCR (RT-PCR) represents the gold standard method, strategies that allow rapid and simple diagnosis are necessary for the early identification of cases. In this study, we evaluated the diagnostic performance of six different commercial rapid antigen tests (Coronavirus antigen [Ag] rapid test cassette [Healgen Scientific, Houston, TX, USA], COVID-19 Ag FIA [Vircell, SD Biosensor Inc., Gyeonggi-do, Republic of Korea], Clinitest rapid COVID-19 antigen test [Siemens, Healthineers, Erlangen, Germany], SARS-CoV-2 rapid antigen test [SD Biosensor; Roche Diagnostics, Basel, Switzerland], Panbio COVID-19 Ag rapid test device [Abbott, Chicago, IL, USA], and SARS-CoV-2 test [MonLab, Barcelona, Spain]) in 130 nasopharyngeal swab samples tested previously by RT-PCR. The overall sensitivity of the rapid tests ranged from 65% to 79%, and the specificity was 100% for all of them. The sensitivity was higher for those samples with RT-PCR cycle threshold (CT) values below 25 and those from patients presenting within the first week of symptoms. The Siemens test showed the highest sensitivity for patients with high viral loads while the Vircell test performed better than the rest for CT values of ≥25. IMPORTANCE The rapid detection of people infected with SARS-CoV-2 is essential for a correct and effective control of the disease it causes. This process must be sensitive, fast, and simple, and it must be possible to carry out in any type of health center. Rapid antigen tests are the answer to this need. Knowing its ability to detect the virus in different stages of the disease is essential for a correct diagnosis, which is why this study has been carried out to evaluate the sensitivity and specificity of 6 different antigens tests in nasopharyngeal smear samples.

Causes of fever in returning travelers: a European multicenter prospective cohort study.

BACKGROUND: Etiological diagnosis of febrile illnesses in returning travelers is a great challenge, particularly when presenting with no focal symptoms [acute undifferentiated febrile illnesses (AUFI)], but is crucial to guide clinical decisions and public health policies. In this study, we describe the frequencies and predictors of the main causes of fever in travelers. METHODS: Prospective European multicenter cohort study of febrile international travelers (November 2017-November 2019). A predefined diagnostic algorithm was used ensuring a systematic evaluation of all participants. After ruling out malaria, PCRs and serologies for dengue, chikungunya and Zika viruses were performed in all patients presenting with AUFI ≤ 14 days after return. Clinical suspicion guided further microbiological investigations. RESULTS: Among 765 enrolled participants, 310/765 (40.5%) had a clear source of infection (mainly traveler's diarrhea or respiratory infections), and 455/765 (59.5%) were categorized as AUFI. AUFI presented longer duration of fever (p < 0.001), higher hospitalization (p < 0.001) and ICU admission rates (p < 0.001). Among travelers with AUFI, 132/455 (29.0%) had viral infections, including 108 arboviruses, 96/455 (21.1%) malaria and 82/455 (18.0%) bacterial infections. The majority of arboviral cases (80/108, 74.1%) was diagnosed between May and November. Dengue was the most frequent arbovirosis (92/108, 85.2%). After 1 month of follow-up, 136/455 (29.9%) patients with AUFI remained undiagnosed using standard diagnostic methods. No relevant differences in laboratory presentation were observed between undiagnosed and bacterial AUFI. CONCLUSIONS: Over 40% of returning travelers with AUFI were diagnosed with malaria or dengue, infections that can be easily diagnosed by rapid diagnostic tests. Arboviruses were the most common cause of AUFI (above malaria) and most cases were diagnosed during Aedes spp. high season. This is particularly relevant for those areas at risk of introduction of these pathogens. Empirical antibiotic regimens including doxycycline or azithromycin should be considered in patients with AUFI, after ruling out malaria and arboviruses.

Molecular Characterization of Imported and Autochthonous Dengue in Northeastern Spain.

Dengue is the most significant arbovirus worldwide and a public health threat to non-endemic areas in which Aedes vectors are present. Autochthonous dengue transmission has been reported in several European countries in the last decade. Infected travelers from endemic regions arriving to areas colonized by Aedes albopictus in Europe need to be monitored in surveillance and control programs. We aimed to perform molecular characterization of RT-PCR-positive dengue cases detected in Catalonia, northeastern Spain, from 2013 to 2018. The basic demographic information and the geographical regions of importation were also analyzed. One-hundred four dengue cases were studied (103 imported infections and the first autochthonous case in our region). The dengue virus strains detected were serotyped and genotyped using molecular methods, and phylogenetic analyses were conducted. All four dengue serotypes were detected in travelers, including up to 10 different genotypes, reflecting the global circulation of dengue in endemic areas. The primary travel-related case of the 2018 autochthonous transmission was not identified, but the molecular analysis revealed dengue serotype 1, genotype I of Asian origin. Our results highlight the diversity of imported dengue virus strains and the role of molecular epidemiology in supporting arbovirus surveillance programs.

Incidence of human granulocytic anaplasmosis in returning travellers with fever.

BACKGROUND: Although tick-borne pathogens have been reported as an important cause of imported fever, the incidence of Anaplasma phagocytophilum, the causative agent of human granulocytic anaplasmosis (HGA), in travellers is unknown. METHODS: We conducted a prospective cohort study to investigate the aetiologies of fever in returning travellers (November 2017-July 2019). Polymerase chain reaction for msp2 gene amplification and indirect immunofluorescence assay for A. phagocitophilum were performed in all returning travellers with undifferentiated non-malarial fever. RESULTS: Among 141 travellers included, 8 patients were diagnosed with probable or confirmed HGA. The overall incidence rate of HGA was 19.9 cases/1000 person-week of travel. The main destination of travel was Asia, accounting for 62.5% patients with HGA. Co-infections were found in 37.5% of patients with HGA. CONCLUSIONS: Diagnosis of HGA and empirical treatment with doxycycline should be considered in travellers with fever.

Zika virus infection in pregnant travellers and impact on childhood neurodevelopment in the first two years of life: A prospective observational study.

BACKGROUND: The emergence of Zika virus (ZIKV) represents a threat with consequences on maternal and children's health. We aimed to assess the clinical and epidemiological characteristics of pregnant women returning from ZIKV affected areas, and the effects of maternal ZIKV infection on birth outcomes and children's health. METHODS: This was a hospital-based prospective observational study conducted at the Hospital Clínic of Barcelona and Hospital Sant Joan de Déu, Barcelona, Spain, from January 2016 to February 2020. RESULTS: One hundred and ninety-five pregnant women who had travelled to ZIKV affected areas during pregnancy were recruited. Four women (2.1%) had a confirmed ZIKV infection, 40 women (20.5%) a probable infection, and 151 (77.4%) were negative for ZIKV. Among the ZIKV confirmed cases, a pregnant woman suffered a miscarriage, highly plausible to be associated with ZIKV infection. Brain cysts and microcalcifications were detected in 7% of fetuses or infants from women with confirmed or probable ZIKV infection. Neurodevelopmental delay in the language function was found in 33.3% out of the 21 children evaluated. CONCLUSIONS: These findings contribute to the understanding of ZIKV prevalence estimates, and the impact of maternal ZIKV infection on pregnancy outcomes and children's health. Results highlight the importance of long-term surveillance in pregnant travellers and their children.

Evaluation of a novel microfluidic immuno-magnetic agglutination assay method for detection of dengue virus NS1 antigen.

BACKGROUND: Dengue virus (DENV) is the most important arbovirus worldwide, causing infections in endemic countries and returning travellers from these areas. Rapid diagnostic tests are needed to improve patient management and monitor local transmission. The detection of DENV non-structural protein 1 (NS1) is a useful tool for the diagnosis, but the currently available methods can be time consuming or lack sensitivity. The objective of our study was to evaluate a new rapid and semi-quantitative microfluidic DENV NS1 immuno-magnetic agglutination assay based on aggregation of magnetic nanoparticles detected by an electronic reader (Virotrack Dengue Acute and Blubox, Blusense diagnostics, Copenhagen, Denmark). METHODOLOGY/PRINCIPAL FINDINGS: A panel of 135 serum samples from travelers returning from dengue endemic countries was analyzed (74 DENV positive samples including the four DENV serotypes, 26 Zika virus positive samples, 25 chikungunya virus positive samples, 5 malaria positive samples and 5 negative samples). Samples were tested by three different antigen detection methods: SD Dengue NS1 Ag ELISA, SD BIOLINE Dengue Duo and ViroTrack Dengue Acute. The sensitivity observed for SD Dengue NS1 Ag ELISA, ViroTrack Dengue Acute and SD BIOLINE Dengue Duo was 97.2%, 91.1% and 68.1%, respectively. All methods showed high specificity (98.4% for ViroTrack Dengue Acute and 100% for both SD Dengue NS1 Ag ELISA and SD BIOLINE Dengue Duo). SD Dengue NS1 Ag ELISA and ViroTrack Dengue Acute only failed to detect samples positive for DENV-2. CONCLUSIONS/SIGNIFICANCE: ViroTrack Dengue Acute is a sensitive and specific assay for DENV NS1 detection. It provides faster results than the ELISA method and a better performance than the rapid immunochromatographic tests. ViroTrack Dengue Acute could represent a valuable tool for rapid diagnosis of DENV infections in returning travellers from endemic countries.

Arbovirus surveillance: first dengue virus detection in local Aedes albopictus mosquitoes in Europe, Catalonia, Spain, 2015.

Dengue has emerged as the most important viral mosquito-borne disease globally. The current risk of dengue outbreaks in Europe appeared with the introduction of the vector Aedes albopictus mosquito in Mediterranean countries. Considering the increasing frequency of dengue epidemics worldwide and the movement of viraemic hosts, it is expected that new autochthonous cases will occur in the future in Europe. Arbovirus surveillance started in Catalonia in 2015 to monitor imported cases and detect possible local arboviral transmission. During 2015, 131 patients with a recent travel history to endemic countries were tested for dengue virus (DENV) and 65 dengue cases were detected. Twenty-eight patients with a febrile illness were viraemic, as demonstrated by a positive real-time RT-PCR test for DENV in serum samples. Entomological investigations around the viraemic cases led to the detection of DENV in a pool of local Ae. albopictus captured in the residency of one case. The sequence of the DENV envelope gene detected in the mosquito pool was identical to that detected in the patient. Our results show how entomological surveillance conducted around viraemic travellers can be effective for early detection of DENV in mosquitoes and thus might help to prevent possible autochthonous transmission.