Distribution of West Nile virus cases in horses reveals different spatiotemporal patterns in eastern and western Canada.

OBJECTIVE: West Nile virus (WNV) became notifiable in horses in 2003 in Canada and has been reported every year since. The objective of this study was to describe the spatiotemporal distribution of WNV in horses between 2003 and 2020 in Canada. ANIMALS: The 848 symptomatic and laboratory-confirmed WNV cases in horses reported to the Canadian Food Inspection Agency between 2003 and 2020. METHODS: Canada was divided into eastern and western regions for analysis. For each case, location and date of notification were captured. Triennial maps were made to describe the spatiotemporal distribution and expansion of reported cases. The association between year and latitude of cases was investigated with simple linear regressions, and space-time clusters were detected with a permutation scan test. RESULTS: Most of the western region showed an extended distribution of WNV cases from 2003 to 2005 and a high recurrence of cases at the census division level. In the eastern region, the expansion of cases was gradual, with new infected census divisions mostly contiguous to previous ones. There was no association between year and latitude of cases. Six spatiotemporal clusters were detected. CLINICAL RELEVANCE: This study confirmed the endemicity of WNV in parts of both regions with local peaks in risk varying in time. Prevention and control efforts should focus on previously infected areas based on the spatiotemporal regional distribution patterns. Incursions of WNV to new areas should also be anticipated. These findings could also contribute to enhancing monitoring and prevention of WNV infections in an integrated surveillance system.

Diagnosis of chylous abdominal effusions: what is the triglyceride threshold value?

Introduction: Chylous abdominal effusions are serious complications that can be triggered by various aetiologies. The biochemical diagnosis of chyle leakage in ascites or in peritoneal fluid capsules relies on the detection of chylomicrons. Assaying the fluid's concentration of triglycerides is still the first-line tool. Given that only one comparative study has sought to quantify the value of the triglyceride assay for diagnosing chylous ascites in humans, our objective was to provide practical triglyceride thresholds. Materials and methods: We conducted a 9-year, retrospective, single-centre study of adult patients and compared a triglyceride assay with lipoprotein gel electrophoresis for the analysis of 90 non-recurring abdominal effusions (ascites and abdominal collections) of which 65 were chylous. Results: A triglyceride threshold of 0.4 mmol/L was associated with a sensitivity > 95%, and a threshold of 2.4 mmol/L was associated with a specificity > 95%. According to Youden index, the best threshold was 0.65 mmol/L with a sensitivity of 88 (77-95)%, a specificity of 72 (51-88)%, and, in our series, a positive predictive value of 89 (79-95)% and a negative predictive value of 69 (48-86)%. Conclusions: In our series, cut-off of 0.4 mmol/L could be used for ruling-out diagnosis of chylous effusions, while cut-off of 2.4 mmol/L could be used for reasonably confirming diagnosis.

Could the chylomicron marker apoB48 be of value in the diagnosis of chylous effusions?

BACKGROUND: Chylous effusions such as chylothorax, chylopericardium and chylous ascites are marked by the abnormal presence of chylomicrons in serous membranes. These relatively rare situations are associated with high morbidity and mortality rates. Given that a macroscopic assessment of the fluid is insufficient, the current gold standard method for chylous effusion is the electrophoretic separation of lipoproteins. Serous effusions are most frequently assayed for triglycerides, with a diagnostic threshold varying between studies. The present study is the first to assess the value of the apolipoprotein B48, specific of the chylomicron, in the diagnosis of chylous effusions. METHODS: A chemiluminescent sandwich enzyme immunoassay was used to measure levels of apoB48 in remnant samples of effusion fluid sent to our laboratory for chylomicron detection and lipid assays. The diagnostic values of apoB48 and triglyceride assays were compared with that of the gold standard method. RESULTS: The triglyceride and apoB48 levels and the triglyceride/cholesterol ratio in the effusion fluid were significantly higher in patients with chylous effusion. The threshold values for apoB48 were respectively 2.45, 0.25 and 19.00 µg/mL for a maximal Youden index, a sensitivity > 95 %, and a specificity > 95 %. The apoB48 assay's diagnostic value might be at least as high as that of a triglyceride assay (area under the receiver operating characteristic curve [95 % confidence interval]: 0.84 [0.72, 0.96]) and 0.80 [0.67, 0.94], respectively). CONCLUSION: ApoB48 appears to be a promising marker for the diagnosis of chylous effusions; the putative diagnostic improvement must be confirmed in larger studies.

Chylopericardium or contamination by injectable lipid emulsion? / « Mets la main sur mon cœur, Et vois comme il se trouble ¼ ­ un pseudo-chylopéricarde ?

Effusions can show some surprises. We document the case of a fourteen-month-old male patient with short-bowel syndrome, hospitalized in a cardiology unit, receiving a chronic parenteral nutrition by a Broviac® catheter. The patient presented several thrombosis following iterative catheter replacements. In parallel with superior vena cava plasty, a right intra-atrial Broviac® catheter was placed in the absence of other peripheral venous accesses. This device has a cutaneous exit site to allow for infusion of a hyperosmolar lipid emulsion. Seven days later, a milky liquid was secreted from pericardial/mediastinal redon. A gel lipoprotein electrophoresis of the fluid suggested a preliminary diagnosis of chylopericardium. However, biochemical testing of certain analytes evoked a parenteral nutrition-related pericardial effusion and a possible pseudochyloperitoneum caused by the shearing of a migrated Broviac® in pericardium. The patient, on a fat-free diet, was admitted to the ICU to drain the effusion and reposition the catheter, with success. In the light of new datas on the interference of parenteral lipid emulsions with the lipoproteins gel electrophoresis, we will try to determine whether the apparent presence of chylomicrons in the gel would be the sign of a lesion of the lymphatic system, or rather the result of a contamination by artificial chylomicron in the lipid emulsion, if not the sign of contaminated blood. In our article, we highlight several considerations in identifying and confirming cases of pericardial effusion, such as chylopericardium and parenteral nutrition-related one, as well as points concerning the use of lipid emulsions for pediatric patients with short-bowel syndrome.

Les liquides d'épanchements peuvent renfermer quelques surprises. Nous documentons le cas d'un patient de quatorze mois, hospitalisé en cardiologie, présentant un syndrome de grêle court et recevant une nutrition parentérale au long cours par cathéter Broviac®. Le patient présentait de multiples occlusions veineuses consécutives aux changements itératifs du dispositif. En parallèle d'une plastie de la veine cave supérieure, un Broviac® a été posé en intra-atrial droit devant l'absence d'autres abords veineux périphériques. Ce dispositif comporte un orifice de sortie sous-cutané pour apporter une solution de nutrition hyperosmolaire de type émulsion lipidique. Le liquide recueilli dans les drains péricardiques en post-opératoire est lactescent, particulièrement à partir du septième jour. Le lipidogramme du liquide d'épanchement péricardique semble conclure à la présence de chylomicrons - un chylopéricarde. Cependant, le dosage de certains analytes penche en faveur d'un perfusopéricarde, probablement pseudochyleux, lié au cisaillement du Broviac® dont l'extrémité a migré de l'oreillette droite au péricarde. Le patient, sous régime sans graisses, sans nutrition parentérale, sera réopéré pour drainer l'épanchement et repositionner le cathéter, avec succès. À la lumière de données originales quant à l'interférence des émulsions lipidiques sur le lipidogramme, nous tâcherons de déterminer si l'apparente présence de chylomicrons sur le gel serait le témoin d'une réelle lésion du lymphatique, ou plutôt le fruit d'une contamination par l'émulsion, si ce n'est par le sang. Des considérations au sujet des épanchements péricardiques, dont les chylopéricarde et nutripéricarde, ainsi que sur les émulsions lipidiques pédiatriques dans le contexte du grêle court émailleront ce travail.

Surveillance of West Nile virus in horses in Canada: A retrospective study of cases reported to the Canadian Food Inspection Agency from 2003 to 2019.

The objectives of the study were to describe the regional and provincial incidence rates and the weekly distribution of 842 reported West Nile virus (WNV) cases in horses in Canada between 2003 and 2019. This study also investigated characteristics of cases reported to the Canadian Food Inspection Agency (CFIA) between 2015 and 2019. The western region (British Columbia, Alberta, Saskatchewan, and Manitoba) had higher incidence rates than the eastern region (Ontario, Quebec, and Atlantic provinces) and overall, Saskatchewan registered the highest incidence. Over the study period, an earlier weekly preliminary onset of WNV cases was observed in the western region. The vast majority of cases were unvaccinated (96%), most cases were Quarter Horses (68%) and the risk of mortality was 31.9%. The findings of this study may be useful in informing veterinary equine practitioners about measures to prevent WNV disease in horses in Canada.

La surveillance du virus du Nil occidental chez les équins au Canada : une étude rétrospective des cas notifiés à l'Agence canadienne d'inspection des aliments de 2003 à 2019. Les objectifs de cette étude étaient de décrire les taux d'incidence régionaux et provinciaux, ainsi que la distribution hebdomadaire des 842 cas équins de virus du Nil occidental (VNO) notifiés à l'Agence canadienne d'inspection des aliments (ACIA) de 2003 à 2019. Les caractéristiques des cas notifiés de 2015 à 2019 ont également été investiguées. La région de l'Ouest (Colombie-Britannique, Alberta, Saskatchewan, Manitoba) a enregistré un taux d'incidence plus élevé que la région de l'Est (Ontario, Québec, provinces de l'Atlantique). Une incidence particulièrement élevée du VNO a été notée en Saskatchewan. Les cas sont survenus plus tôt dans l'Ouest que dans l'Est durant la période d'étude. La majorité des cas n'étaient pas vaccinés (96 %) et ils provenaient surtout de Quarter Horses (68 %). Le risque de mortalité était de 31,9 %. Cette étude fournit des éléments clés d'information pour guider les vétérinaires praticiens dans l'application des mesures de prévention du VNO chez les chevaux au Canada.(Traduit par les auteurs).