[Identification and investigation of clusters during the COVID-19 pandemic Experiences from the canton of Vaud]. / Traçage rétrospectif et gestion des clusters pendant l'épidémie de Covid-19 - Applications dans le canton de Vaud.

Persons with SARS-CoV2 can be contagious with few or no symptoms. They can infect others in private, during education or work without knowing it. Few so-called super-propagators can thus initiate clusters of infections and chains of transmission. Isolation of new cases and quarantine of their contacts (forward contact tracing) often does not uncover such situations. Adding detailed backward investigations of events and places with elevated risk of transmission can increase the identification of potentially infected persons. These can then be quarantined, and chains of transmission be interrupted. We describe the principles and challenges of cluster investigation, epidemiological methods and IT tools that we deve loped at the Centre for contact tracing, Vaud. Knowledge of this method is useful in general clinical practice during a pandemic.

La plupart des personnes infectées par le SARS-CoV-2 sont contagieuses même si elles présentent peu ou pas de symptômes. Quelques individus, dits superpropagateurs, peuvent ainsi être à l'origine de clusters d'infections et de chaînes de transmission. L'isolement des nouveaux cas et la mise en quarantaine de leurs contacts ne permettent généralement pas de découvrir de telles situations. L'ajout d'enquêtes rétrospectives centrées sur la recherche de clusters peut accroître l'identification des personnes potentiellement infectées. Nous décrivons les principes et les défis de l'investigation par cluster, les méthodes épidémiologiques et les outils informatiques que nous avons développés au Centre de traçage du canton de Vaud. La connaissance de cette méthode est utile en pratique clinique lors d'une pandémie.

Imaging mass spectrometry of elements in forensic cases by LA-ICP-MS.

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was performed to map elements in thin formalin-fixed paraffin-embedded tissue sections of two forensic cases with firearm and electrocution injuries, respectively. In both cases, histological examination of the wounded tissue regions revealed the presence of exogenous aggregates that may be interpreted as metallic depositions. The use of imaging LA-ICP-MS allowed us to unambiguously determine the elemental composition of the observed aggregates assisting the pathologist in case assessments. To the best of our knowledge, we demonstrate for the first time the use of imaging LA-ICP-MS as a complementary tool for forensic pathologists and toxicologists in order to map the presence of metals and other elements in thin tissue sections of post-mortem cases.

Sudden cardiac death and sarcoidosis of the heart in a young patient.

Sarcoidosis is a granulomatous disease of unknown etiology affecting any organ, microscopically characterized by noncaseating granulomata. Cardiac involvement in sarcoidosis has been reported. It might be symptomatic or not and even revealed by sudden death. Heart conduction system is rarely investigated at autopsy, even in cases of sudden cardiac death. We present a case of a 32-year-old woman who died suddenly. The examination of the heart conduction system revealed a cardiac sarcoidosis that could explain the sudden death. The review of clinical data of the patient revealed some symptoms consistent/in agreement with this hypothesis. Cardiac sarcoidosis remains a diagnostic challenge and can be easily missed, clinically and pathologically. The retrospective analysis of clinical data and autopsy results of fatal and unusual cases might help to better understand sarcoidosis and its clinical presentations. Examination of the cardiac conduction system is crucial in selected cases of sudden cardiac death.