Update on HSV and VZV infections of the brain.

HSV and VZV are the most frequently identified pathogen in encephalitis cases in France. Recent guidelines were provided by some scientific societies, for the management of encephalitis. PCR is the gold standard for the diagnosis, and the first-line imaging tool is MRI. Sequels are important and there is an absolute need for a better evaluation and management in the future to reduce the short- and long-term consequences, beyond reducing the case fatality rate. A better management of sequels is important. Autoimmune encephalitis triggered by HSV is a recent syndrome, which leads to consider it as a major issue in the management of patients. The final point is the importance of inflammation in explaining disorders and severity, meaning that anti-inflammatory treatments of whatever nature have to be validated.

Management of infectious encephalitis in adults: Highlights from the French guidelines (short version).

The article highlights the French clinical guidelines for the management of adult patients with acute infectious encephalitis.

Are guidelines on the management of non-tuberculous mycobacteria lung infections respected and what are the consequences for patients? A French retrospective study from 2007 to 2014.

Diagnosis and treatment of lung infections caused by non-tuberculous mycobacteria (NTM) remain challenging. Adherence of the clinicians to the American Thoracic Society (ATS) and the Infectious Diseases Society of America (IDSA) 2007 guidelines is often incomplete. Between 2007 and 2014, in Grenoble Alpes University Hospital, France, 132 patients had NTM-positive cultures from lower respiratory tract (LRT) samples. We retrospectively collected diagnosis, treatment, and outcome data of patients, and evaluated the adherence of clinicians to ATS/IDSA guidelines and the consequences of patients' prognoses. Using the ATS/IDSA definitions, 31 out of 132 patients (23.5%) were considered infected, 57 out of 132 patients (43.2%) were considered colonised, 33 out of 132 (25%) were contaminated and 11 (8.4%) had missing data. Among the 31 NTM-infected patients, M. avium (23 out of 31, 74.2%) was most frequently involved. The main risk factor for NTM lung infection was underlying lung disease (30 out of 31, 96.8%). Treatment was not appropriate according to current guidelines in 58.1% of infected patients (18 out of 31). Mainly, the antibiotic treatment was installed based on radiological signs (p = 0.0006), sputum results and bronchoalveolar lavage results (p < 0.0001 and p = 0.003 respectively). Most antibiotic regimens included a macrolide (83.4%). Patients receiving appropriate treatment had the same cure rates as those receiving inappropriate treatment (p = 0.22) and similar relapse rates (p = 0.92). Current medical practices for the treatment of NTM lung infections in our institution are not consistent with the ATS/IDSA guidelines. This could potentially affect the prognosis of these patients and favour the emergence of macrolide resistance in NTM species.

Pneumocystis jirovecii (Pj) quantitative PCR to differentiate Pj pneumonia from Pj colonization in immunocompromised patients.

Conventional polymerase chain reaction (PCR) in respiratory samples does not differentiate between Pneumocystis pneumonia (PCP) and Pneumocystis jirovecii (Pj) colonization. We used Pj real-time quantitative PCR (qPCR) with the objective to discriminate PCP from Pj colonization in immunocompromised patients. All positive Pj qPCR [targeting the major surface glycoprotein (MSG) gene] obtained in respiratory samples from immunocompromised patients presenting pneumonia at the Grenoble University Hospital, France, were collected between August 2009 and April 2011. Diagnoses were retrospectively determined by a multidisciplinary group of experts blinded to the Pj qPCR results. Thirty-one bronchoalveolar lavages and four broncho aspirations positive for the Pj qPCR were obtained from 35 immunocompromised patients. Diagnoses of definite, probable, and possible PCP, and pneumonia from another etiology were retrospectively made for 7, 4, 5, and 19 patients, respectively. Copy numbers were significantly higher in the "definite group" (median 465,000 copies/ml) than in the "probable group" (median 38,600 copies/ml), the "possible group" (median 1,032 copies/ml), and the "other diagnosis group" (median 390 copies/ml). With the value of 3,160 copies/ml, the sensitivity and specificity of qPCR for the diagnosis of PCP were 100 % and 70 %, respectively. With the value of 31,600 copies/ml, the sensitivity and specificity were 80 % and 100 %, respectively. The positive predictive value was 100 % for results with more than 31,600 copies/ml and the negative predictive value was 100 % for results with fewer than 3,160 copies/ml. qPCR targeting the MSG gene can be helpful to discriminate PCP from Pj colonization in immunocompromised patients, using two cut-off values, with a gray zone between them.

The features of infectious diseases departments and anti-infective practices in France and Turkey: a cross-sectional study.

The aim of this study was to assess the infectious diseases (ID) wards of tertiary hospitals in France and Turkey for technical capacity, infection control, characteristics of patients, infections, infecting organisms, and therapeutic approaches. This cross-sectional study was carried out on a single day on one of the weekdays of June 17-21, 2013. Overall, 36 ID departments from Turkey (n = 21) and France (n = 15) were involved. On the study day, 273 patients were hospitalized in Turkish and 324 patients were followed in French ID departments. The numbers of patients and beds in the hospitals, and presence of an intensive care unit (ICU) room in the ID ward was not different in both France and Turkey. Bed occupancy in the ID ward, single rooms, and negative pressure rooms were significantly higher in France. The presence of a laboratory inside the ID ward was more common in Turkish ID wards. The configuration of infection control committees, and their qualifications and surveillance types were quite similar in both countries. Although differences existed based on epidemiology, the distribution of infections were uniform on both sides. In Turkey, anti-Gram-positive agents, carbapenems, and tigecycline, and in France, cephalosporins, penicillins, aminoglycosides, and metronidazole were more frequently preferred. Enteric Gram-negatives and hepatitis B and C were more frequent in Turkey, while human immunodeficiency virus (HIV) and streptococci were more common in France (p < 0.05 for all significances). Various differences and similarities existed in France and Turkey in the ID wards. However, the current scene is that ID are managed with high standards in both countries.

Vaccination of teenagers in France over a 10-year period (2012-2021).

OBJECTIVES: The objectives were to assess trends over the past 10 years in vaccination coverage rates (VCR) among adolescents in France aged 14-15 years, factors influencing decisions to vaccinate, and mothers' opinions on adolescent vaccination. PATIENTS AND METHODS: The 'Vaccinoscopie' internet survey is completed each year by mothers of adolescents, with questions about vaccinations received by their children, and their attitudes and barriers to vaccination. The 2012 to 2021 surveys were analyzed in this study, including data from 1500 adolescents in 2012 and 1000 adolescents each year from 2013 to 2021. RESULTS: None of the adolescent VCR targets were met, despite significant increases since 2012 for vaccines with the lowest coverage rates and vaccines with high but insufficient coverage i.e., meningococcal C (28.7% to 60.8%), HPV in girls (14.2% to 40.8%), hepatitis B (31.6% to 47.3%) and pertussis (76.3% to 91.0%). Physicians remained the primary source of vaccination information for 90.4% of mothers, and their advice had a real impact on improving VCRs. Adolescents were increasingly involved (40.1%) in decisions about vaccination. Depending on the vaccine, over 80% of mothers currently consider adolescent vaccination as useful or essential. Since 2017, they also feel better informed. CONCLUSIONS: Low and under-target VCRs put adolescents at risk of severe disease, and do not enable herd immunity or reduced transmission to other vulnerable age groups to be accomplished. Healthcare professionals must take every opportunity to check adolescents' vaccination status and recommend catch-up vaccines where applicable. Vaccination in schools should be considered.

Case definitions, diagnostic algorithms, and priorities in encephalitis: consensus statement of the international encephalitis consortium.

BACKGROUND: Encephalitis continues to result in substantial morbidity and mortality worldwide. Advances in diagnosis and management have been limited, in part, by a lack of consensus on case definitions, standardized diagnostic approaches, and priorities for research. METHODS: In March 2012, the International Encephalitis Consortium, a committee begun in 2010 with members worldwide, held a meeting in Atlanta to discuss recent advances in encephalitis and to set priorities for future study. RESULTS: We present a consensus document that proposes a standardized case definition and diagnostic guidelines for evaluation of adults and children with suspected encephalitis. In addition, areas of research priority, including host genetics and selected emerging infections, are discussed. CONCLUSIONS: We anticipate that this document, representing a synthesis of our discussions and supported by literature, will serve as a practical aid to clinicians evaluating patients with suspected encephalitis and will identify key areas and approaches to advance our knowledge of encephalitis.

Epidemiology of infectious encephalitis, differences between a prospective study and hospital discharge data.

The French epidemiology of infectious encephalitis has been described in a 2007 prospective study. We compared these results with available data (demographic features, causative agents, case-fatality ratio) obtained through the French national hospital discharge 2007 database (PMSI), in order to evaluate it as a surveillance tool for encephalitis. Causative agents were identified in 52% of cases in the study, and 38% in PMSI (P < 0·001). The incidence of encephalitis in France in 2007 was estimated as 2·6 cases/100 000 inhabitants. HSV and VZV were the most frequent aetiological agents in both databases with similar rates. Listeria monocytogenes and Mycobacterium tuberculosis were less frequent in PMSI than in the study (Listeria: 2% vs. 5%, P = 0·001; Mycobacterium: 2% vs. 8%, P < 0·001). The case-fatality ratios were similar, except for Listeria (46% in the study vs. 16%). Nevertheless, despite the absence of case definitions and a possible misclassification weakening PMSI data, we suggest that PMSI may be used as a basic surveillance tool at a limited cost.

[Fractures of the thoracic and lumbar spine in children and adolescents]. / Frakturen der Brust- und Lendenwirbelsäule im Wachstumsalter.

BACKGROUND: Only 1.5-2% of all fractures in children and adolescents are fractures of the thoracic and lumbar spine. Treatment is most often conservative. This study compares the own experience with the recent literature. MATERIAL AND METHODS: Over a 48 month period all patients with fractures of the thoracic and lumbar spine, younger than 16 years were included prospectively. Of the patients 67 underwent follow-up investigations after 3-36 months. RESULTS: The average age of the patients was 11.9 years. Sports (53%) and traffic (28%) accidents were most frequent. Fractures most often appeared in the mid-thoracic (47%) and thoracolumbar spine (41%). Operative treatment was performed in 9 cases (10.4%). Secondary loss of alignment was not observed neither after conservative nor operative treatment. Neurological deficits (n=2) did not completely improve. CONCLUSIONS: Most fractures of the thoracic and lumbar spine heal fast and without any sequelae. Unstable fractures of type B and C (exclusively occurring as a result of traffic accidents) need operative stabilization as in adults.

SPILF update on bacterial arthritis in adults and children.

In 2020 the French Society of Rhumatology (SFR) published an update of the 1990 recommendations for management of bacterial arthritis in adults. While we (French ID Society, SPILF) totally endorse this update, we wished to provide further information about specific antibiotic treatments. The present update focuses on antibiotics with good distribution in bone and joint. It is important to monitor their dosage, which should be maximized according to PK/PD parameters. Dosages proposed in this update are high, with the optimized mode of administration for intravenous betalactams (continuous or intermittent infusion). We give tools for the best dosage adaptation to conditions such as obesity or renal insufficiency. In case of enterobacter infection, with an antibiogram result "susceptible for high dosage", we recommend the requesting of specialized advice from an ID physician. More often than not, it is possible to prescribe antibiotics via the oral route as soon as blood cultures are sterile and clinical have symptoms shown improvement. Duration of antibiotic treatment is 6 weeks for Staphylococcus aureus, and 4 weeks for the other bacteria (except for Neisseria: 7 days).

Point prevalence survey of antibiotic use in French hospitals in 2009.

OBJECTIVES: To evaluate the feasibility of a point prevalence survey for monitoring antibiotic use in a voluntary sample of French hospitals. METHODS: Demographic and medical data were collected for all inpatients. Additional characteristics regarding antimicrobial treatment, type of infection and microbiological results were collected only for patients receiving antimicrobials. RESULTS: Among 3964 patients in 38 hospitals, 343 (8.7%) received antimicrobial prophylaxis and 1276 (32.2%) antimicrobial therapy. The duration of surgical antimicrobial prophylaxis was >1 day in 41 out of 200 (21%) of the cases. Among patients with antimicrobial therapy, 959 (75.2%) received ß-lactams (including 34.8% penicillins with ß-lactam inhibitors, 22.1% third-generation cephalosporins and 7.8% carbapenems) and 301 (23.6%) received fluoroquinolones (50% orally). A total of 518 (40.6%) patients were treated with more than one drug and 345 (27.2%) were treated for >7 days. Patients treated for hospital-acquired infections (39.2%) were more likely to receive combinations (47.6% versus 34.4%, P < 0.01), carbapenems (14.4% versus 2.6%, P < 0.01), glycopeptides (14.4% versus 3.7%, P < 0.01) and antifungals (17% versus 5.3%, P < 0.01) for a longer duration (7.8 versus 6 days, P < 0.01). Fifty-six patients (4.4%) were treated for >7 days and did not have any microbiological sample drawn. The time allocated for the survey represented 18.3-25.0 h for 100 patients. CONCLUSIONS: The data provide directions for further interventions, such as better use of diagnostic tools, decreasing the treatment duration and the use of combinations. In addition, the survey shows that, although cumbersome, it is feasible to improve the representativeness of national data in European surveys.

Herpes simplex encephalitis and management of acyclovir in encephalitis patients in France.

This study reports on the clinical profiles of herpes simplex encephalitis (HSE) case-patients and the management of acyclovir prescriptions. We designed a study on the causes of encephalitis in France in 2007. Case-patients fulfilling the inclusion criteria were enrolled in all the hospitals that volunteered to participate. Fifty-five of 253 enrolled case-patients were diagnosed with HSE. Three (5%) HSE patients died and 48 (89%) were discharged with persistent neurological symptoms. All HSE patients were prescribed acyclovir, 10 of whom had a 2-week course; 42 a 3-week course; two received incomplete courses; and one received two courses of 21 days each due to relapse. The acyclovir dosage was reported for 45 adult HSE patients, 25 (53%) of whom received 10 mg/kg t.i.d. and 22 (47%) received 15 mg/kg t.i.d. The mortality rate was low despite 49% of patients being admitted to intensive-care units. A high dose of acyclovir was not associated with a better outcome in HSE patients. Most patients had persisting symptoms on discharge suggesting neuropsychological rehabilitation is an important issue for survivors.

Changing profile of encephalitis: Results of a 4-year study in France.

CONTEXT: In 2007, we performed a nationwide prospective study to assess the epidemiology of encephalitis in France. We aimed to evaluate epidemiological changes 10years later. METHODS: We performed a 4-year prospective cohort study in France (ENCEIF) from 2016 to 2019. Medical history, comorbidities, as well as clinical, biological, imaging, and demographic data were collected. For the comparison analysis, we selected similar data from adult patients enrolled in the 2007 study. We used Stata statistical software, version 15 (Stata Corp). Indicative variable distributions were compared using Pearson's Chi2 test, and means were compared using Student's t-test for continuous variables. RESULTS: We analyzed 494 cases from 62 hospitals. A causative agent was identified in 65.7% of cases. Viruses represented 81.8% of causative agents, Herpesviridae being the most frequent (63.6%). Arboviruses accounted for 10.8%. Bacteria and parasites were responsible for respectively 14.8% and 1.2% of documented cases. Zoonotic infections represented 21% of cases. When comparing ENCEIF with the 2007 cohort (222 adults patients from 59 hospitals), a higher proportion of etiologies were obtained in 2016-2019 (66% vs. 53%). Between 2007 and 2016-2019, the proportions of Herpes simplex virus and Listeria encephalitis cases remained similar, but the proportion of tuberculosis cases decreased (P=0.0001), while tick-borne encephalitis virus (P=0.01) and VZV cases (P=0.03) increased. In the 2016-2019 study, 32 causative agents were identified, whereas only 17 were identified in the 2007 study. CONCLUSION: Our results emphasize the need to regularly perform such studies to monitor the evolution of infectious encephalitis and to adapt guidelines.

Appropriateness of blood culture testing parameters in routine practice. Results from a cross-sectional study.

We aimed to assess the appropriateness of routine blood culture testing parameters and antimicrobial therapy for patients with suspected bloodstream infection. We conducted a cross-sectional study of blood cultures registered in the microbiological laboratory at a university-affiliated hospital from 4 to 15 June 2007. Using a structured implicit chart review, two infectious disease specialists assessed the appropriateness of the testing parameters and antimicrobial therapy. Overall, 2,696 blood culture bottles were collected from 260 patients during their stay, including 955 bottles that were evaluated during the study period. The indication of fungal and bacterial blood cultures was rated as appropriate for 75% (95% confidence interval [CI], 65-83) and 91% (95% CI, 87-95) of patients. Only 45% (95% CI, 39-52) of patients had an adequate number of blood cultures (i.e., two to four). An optimal volume of blood (i.e., ≥10 mL) was inoculated in 13% (95% CI, 11-15) of adult bottles. Empirical antimicrobial therapy was appropriate for 60% (95% CI, 43-76) of patients with positive blood cultures. There is room for improvement regarding routine blood culture testing parameters and antimicrobial therapy. The effectiveness of multifaceted interventions in altering the appropriateness of blood culture parameters deserves further research.

Evolution between 2008 and 2018 of mothers' perception regarding vaccination and infant vaccine coverage in France.

OBJECTIVE: Monitoring of vaccination coverage rates (VCRs) is essential to assess the implementation of a country's vaccine policy and its effectiveness. Through the French Vaccinoscopy study, we measured the evolution of VCRs as well as mothers' opinion towards vaccination between 2008 and 2018, before and after implementation of infant mandatory vaccination extension. METHODS: This is a study based on an internet-standardised questionnaire. In 2018, a representative sample of 3000 mothers of infants 0 to 35 months of age answered on their opinion on vaccination and reported all vaccinations recorded in their child's health record. RESULTS: On the period considered, infant VCRs were stable and high for diphtheria, tetanus, poliomyelitis, pertussis and pneumococcus components and progressed for measles, mumps rubella, 2 doses at 24 months of age from 45.3% in 2008 to 81.0% in 2018, hepatitis B (HepB) complete primovaccination at 6 months of age from 45.9% in 2008 to 86.3% in 2017 and 95.5% in 2018, and meningococcus C (MenC) 1 dose at 6 months of age from 43.0% in 2017 to 74.2% in 2018. In 2018, 69.0% of mothers were in favour of vaccination while this rate dropped from 80.2% in 2012 to 64.0% in 2017, and 80.8 to 89.6% perceived HepB, MenC measles and pertussis vaccinations as useful/essential, percentages in progress versus 2017. CONCLUSION: Following the implementation of infant mandatory vaccination in 2018, proportion of mothers in favour of vaccination increased significantly. HepB and MenC VCRs significantly progressed between 2017 and 2018.

Protocol for DexEnceph: a randomised controlled trial of dexamethasone therapy in adults with herpes simplex virus encephalitis.

INTRODUCTION: Herpes simplex virus (HSV) encephalitis is a rare severe form of brain inflammation that commonly leaves survivors and their families with devastating long-term consequences. The virus particularly targets the temporal lobe of the brain causing debilitating problems in memory, especially verbal memory. It is postulated that immunomodulation with the corticosteroid, dexamethasone, could improve outcomes by reducing brain swelling. However, there are concerns (so far not observed) that such immunosuppression might facilitate increased viral replication with resultant worsening of disease. A previous trail closed early because of slow recruitment. METHOD: DexEnceph is a pragmatic multicentre, randomised, controlled, open-label, observer-blind trial to determine whether adults with HSV encephalitis who receive dexamethasone alongside standard antiviral treatment with aciclovir for have improved clinical outcomes compared with those who receive standard treatment alone. Overall, 90 patients with HSV encephalitis are being recruited from a target of 45 recruiting sites; patients are randomised 1:1 to the dexamethasone or control arms of the study. The primary outcome measured is verbal memory as assessed by the Weschler Memory Scale fourth edition Auditory Memory Index at 26 weeks after randomisation. Secondary outcomes are measured up to 72 weeks include additional neuropsychological, clinical and functional outcomes as well as comparison of neuroimaging findings. Patient safety monitoring occurs throughout and includes the detection of HSV DNA in cerebrospinal fluid 2 weeks after randomisation, which is indicative of ongoing viral replication. Innovative methods are being used to ensure recrutiment targets are met for this rare disease. DISCUSSION: DexEnceph aims to be the first completed randomised controlled trial of corticosteroid therapy in HSV encephalitis. The results will provide evidence for future practice in managing adults with the condition and has the potential to improve outcomes . ETHICS AND DISSEMINATION: The trial has ethical approval from the UK National Research Ethics Committee (Liverpool Central, REF: 15/NW/0545, 10 August 2015). Protocol V.2.1, July 2019. The results will be published and presented as soon as possible on completion. TRIAL REGISTRATION NUMBERS: ISRCTN11774734, EUDRACT 2015-001609-16.

Infant mandatory vaccinations: Confirmation of a positive impact.

OBJECTIVE: Infant vaccines protecting against 11 diseases have changed from recommended to mandatory status in France for all children born from first of January 2018. Through Vaccinoscopie survey, we measured for the second consecutive year the impact of this new policy on vaccine coverage rates (VCRs) and mothers' perception regarding vaccination. METHODS: Web-based survey on a representative sample of 1500 mothers of 0 to 17-month-old infants. RESULTS: Non-optimal VCRs continued to increase in 2019 versus 2017 (according to age, +7 to 8 points VCR for Hepatitis B and +36 to 68 points for Meningococcus C). After a progressive decrease between 2012 and 2017, the rate of favorable mothers' opinion towards vaccination continued to progress in 2018 and 2019. CONCLUSION: These results confirmed the positive impact of this new law on infant VCRs and mothers' favorable opinion regarding vaccination.

[Prevention of postoperative or associated of care pelvic inflammatory diseases. Is there a need for antibiotic prophylaxis for first trimester surgical-induced abortion to prevent pelvic inflammatory diseases? CNGOF good practice points]. / Prévention des infections génitales hautes postopératoires ou associées aux soins. Faut-il proposer une antibioprophylaxie lors des interruptions volontaires de grossesse chirurgicales pour prévenir les infections génitales hautes ? Conseils de bonne pratique du CNGOF.

Antibiotic prophylaxis is not recommended during surgical induced abortions. Systematic screening for Chlamydia trachomatis and Neisseria gonorrheae infection by polymerase chain reaction (PCR) on a vaginal sample is recommended before any surgical abortion. Moreover, the bacteriological result should be available before the abortion so that antibiotic treatment effective against the identified bacteria, if any, can be proposed before the procedure. The absence of bacteriological result on the day of the abortion must not, however, delay the procedure. If screening is positive for a sexually transmitted infection (STI), and the bacteriological result is only available after the abortion, it is recommended that antibiotic treatment start as soon as possible. The first-line antibiotic treatment is ceftriaxone 500mg in a single dose by the intramuscular route for N. gonorrheae, doxycycline 200mg per day orally for 7 days for C. trachomatis and azithromycin 500mg the first day (D1) then 250mg per day from D2 to D4 orally if Mycoplasma genitalium is detected by multiplex PCR. In case of positive screening, antibiotic treatment of the woman's partner(s) is recommended, adapted to the STI agent(s).

[Treatment of community acquired bacterial meningitis, after microbiological identification]. / Le traitement des méningites bactériennes communautaires, après identification microbiologique.

INTRODUCTION: Are the 1996 SPILF consensus conference recommendations on bacterial meningitis (BM) still adequate? OBJECTIVE: The literature published after 1996 was analyzed and the reviewers summarized the available data on antibiotic treatment once BM microbiological diagnosis made or strongly suspected. METHOD: A review was made using PubMed, 10,015 references were examined. Only articles published after 1997 were analyzed. RESULTS: No study allowed to recommend other regimens than those previously recommended in 1996, in case of meningococcal or pneumococcal infection: 3rd generation cephalosporin or amoxicillin, combined with vancomycin in case of penicillin-intermediate or resistant pneumococcus. In some cases, alternatives are possible, in case of pneumococcal infection: meropenem or antipneumococcal fluoroquinolone were recommended by US guidelines. New antibiotics available on the market were tested using experimental pneumococcal meningitis models: daptomycin and ertapenem seemed to be useful but linezolid was not. Among the antibiotic combinations tested, ceftriaxone+rifampicine demonstrated a better efficacy than ceftriaxone+vancomycin. There was not contributive published data on the length of treatment for bacterial meningitis. CONCLUSION: No assessed arguments could be found to modify previous guidelines. In case of problem with penicillin-resistant pneumococci, penem or a combination using ceftriaxone and rifampicin may be used.

Diagnostic approach to encephalitis and meningoencephalitis in adult returning travellers.

BACKGROUND: Encephalitis and meningoencephalitis are severe, sometime life-threatening infections of the central nervous system. Travellers may be exposed to a variety of neurotropic pathogens. AIMS: We propose to review known infectious causes of encephalitis in adults acquired outside Europe, and how to identify them. SOURCES: We used Pubmed and Embase, to search the most relevant publications over the last years. CONTENT: Microbiologic tests and radiological tools to best identify the causative pathogen in travellers presenting with encephalitis and ME are presented in this narrative review, as well as a diagnostic approach tailored to the visited area and types of exposures. IMPLICATIONS: This review highlights the diagnostic difficulties inherent to exotic causes of central nervous system infections, and attempts to guide clinicians with respect to which microbiological tests to consider, in addition to brain MRI, when approaching a returning traveller presenting with encephalitis.