First autochthonous human West Nile virus infections in the Netherlands, July to August 2020.

In October 2020, the first case of autochthonous West Nile virus neuroinvasive disease was diagnosed in the Netherlands with a presumed infection in the last week of August. Investigations revealed five more cases of local West Nile virus (WNV) infection. The cases resided in a region where WNV was detected in a bird and mosquitoes in August 2020. Molecular analysis was successful for two cases and identified the presence of WNV lineage 2.

National laboratory-based surveillance system for antimicrobial resistance: a successful tool to support the control of antimicrobial resistance in the Netherlands.

An important cornerstone in the control of antimicrobial resistance (AMR) is a well-designed quantitative system for the surveillance of spread and temporal trends in AMR. Since 2008, the Dutch national AMR surveillance system, based on routine data from medical microbiological laboratories (MMLs), has developed into a successful tool to support the control of AMR in the Netherlands. It provides background information for policy making in public health and healthcare services, supports development of empirical antibiotic therapy guidelines and facilitates in-depth research. In addition, participation of the MMLs in the national AMR surveillance network has contributed to sharing of knowledge and quality improvement. A future improvement will be the implementation of a new semantic standard together with standardised data transfer, which will reduce errors in data handling and enable a more real-time surveillance. Furthermore, the scientific impact and the possibility of detecting outbreaks may be amplified by merging the AMR surveillance database with databases from selected pathogen-based surveillance programmes containing patient data and genotypic typing data.

Sarcoidosis and Purified Protein Derivative reactivity.

BACKGROUND: The possible association between (tuberculous and nontuberculous) mycobacterial infections and sarcoidosis is still a matter of dispute. Using diagnostic tests for specific T-cell responses, this association can be investigated in an innovative manner. OBJECTIVE: To measure the T-cell responsiveness to the purified protein derivative (PPD) antigen in blood and broncho-alveolar lavage (BAL) fluid in patients with sarcoidosis and patients with other causes of interstitial lung disease. It was hypothesized that if a mycobacterial infection of the lung is of importance for the development of sarcoidosis, T-cell responsiveness towards the PPD antigen would be increased in patients with sarcoidosis when compared to patients with other causes of interstitial lung disease. METHODS: A single-center study was conducted which included patients with and without sarcoidosis. Venous blood was collected and BAL was performed for, inter alia, Interferon Gamma Release Assay´s (IGRA) with different stimulating antigens, including PPD, ESAT-6, CFP-10 and, as a control, Epstein-Barr virus (EBV). RESULTS: A total of 118 patients were included. There is no difference between PPD reactivity in BAL fluid in patients with or without sarcoidosis. In patients without sarcoidosis, ELISpot PPD in blood shows more reactivity compared to patients with sarcoidosis, although this difference is not significant. ELISpot EBV and TB results are not significant different between both groups. CONCLUSION: These results provide no evidence for the involvement of different mycobacteria in the pathogenesis of sarcoidosis.

Interferon gamma release assays for diagnosing active and latent tuberculosis.

BACKGROUND: In view of the continuing global epidemic of tuberculosis (TB), adequate diagnosis is crucial for controlling this disease. Two commercial interferon gamma release assays (IGRA) have become available: the QuantiFERON-TB (QFT) and the T-SPOT.TB (TSPOT). They offer an important new tool for detecting both latent and active TB. In particular, the increased specificity as compared with the tuberculin skin test (TST) has resulted in many now (considering) replacing TST with IGRA. OBJECTIVE: This review tries to offer the reader more insight from a clinical perspective into the applicability of IGRA for both latent and active TB. CONCLUSION: Although both IGRA are based on the same principle, they have marked different performance characteristics and it seems likely that both assays will establish their own niche. The increased specificity and sensitivity of IGRA in various settings as compared with TST show us that IGRA are here to stay. QFT might be the preferred tool for large-scale contact tracing, but in most clinical settings TSPOT has to be preferred. Much knowledge on IGRA has already been obtained in a short time; however, many questions remain unresolved, such as likelihood for developing active TB in individuals with a negative IGRA in contact tracing in various subgroups and the applicability of IGRA for detecting active TB.

Molecular diagnosis of Epstein-Barr virus infections.

Epstein-Barr virus (EBV) is an ubiquitous virus infecting the majority of people worldwide. Primary infection is usually sub clinical, except in a number of cases when it causes infectious mononucleosis. This diagnosis is usually based on serology, however, this may not always be conclusive. In these cases, additional EBV PCR can be a helpful tool. Latently present in memory B lymphocytes, EBV can be encountered throughout the body. However, presence in cell free serum or plasma is rare and can be a sign of virus reactivation. EBV is etiologically linked to a number of malignancies, such as nasopharyngeal lymphoma, Hodgkin lymphoma and post-transplant lymphoproliferative disease. Here, knowledge about presence and load of EBV in both target organ and serum is helpful for diagnosing, staging, prognosis and subsequent monitoring of the effect of therapy. Debate is still going on as to which substrate is preferred for analysis, what gene target to use for PCR and which cut-off values to use for diagnosis and start of pre-emptive therapy.