Applying a One Health Approach in Global Health and Medicine: Enhancing Involvement of Medical Schools and Global Health Centers.

Background: Multidisciplinary and multisectoral approaches such as One Health and related concepts (e.g., Planetary Health, EcoHealth) offer opportunities for synergistic expertise to address complex health threats.

Institutionalizing One Health: From Assessment to Action.

A One Health approach is critical to strengthening health security at country, regional, and global levels. However, operationally its uptake remains limited. Recent momentum in assessing capacity to effectively prevent, detect, and respond to disease threats has resulted in identification of gaps that require dedicated action.

Transcriptome analysis of neoplastic hemocytes in soft-shell clams Mya arenaria: Focus on cell cycle molecular mechanism.

In North America, a high mortality of soft-shell clams Mya arenaria was found to be related to the disease known as disseminated neoplasia (DN). Disseminated neoplasia is commonly recognized as a tetraploid disorder related to a disruption of the cell cycle. However, the molecular mechanisms by which hemocytes of clams are transformed in the course of DN remain by far unknown.

Effects of pesticide compounds (chlorothalonil and mancozeb) and benzo[a]pyrene mixture on aryl hydrocarbon receptor, p53 and ubiquitin gene expression levels in haemocytes of soft-shell clams (Mya arenaria).

The aim of this study is to investigate the effects of the pesticides/polycyclic aromatic hydrocarbon mixture on aryl hydrocarbon receptor (AhR), p53 and ubiquitin mRNA level in haemocytes of Mya arenaria exposed to a mixture of chlorothalonil, mancozeb and benzo[a]pyrene (BaP) for 48 and 72 h. AhR, p53 and ubiquitin gene expression levels were quantified using quantitative Real-time PCR. For robust and accurate quantification of transcripts, suitable housekeeping genes were selected from four sets of ribosomal and elongation factors transcripts previously sequenced from Mya arenaria using geNorm open source software.

Induction of transposase and polyprotein RNA levels in disseminated neoplastic hemocytes of soft-shell clams: Mya arenaria.

In Prince Edward Island, a high mortality of soft-shell clams Mya arenaria was found to be related to the disease known as disseminated neoplasia (DN). However, the molecular mechanisms by which hemocytes of clams are transformed in the course of DN remain by far unknown. This study aims at identifying the transcripts involved in the development of the disease.

Identification and expression of immune-related genes in hemocytes of soft-shell clams, Mya arenaria, challenged with Vibrio splendidus.

Although the mollusc immune system has been studied at the cellular level, the response to pathogens at gene expression level has not been thoroughly investigated. This study aimed to investigate the early molecular response of hemocytes of soft-shell clams, Mya arenaria, to Vibrio splendidus strain LGP32 by identification of transcripts involved in immune defense. The Suppression Subtractive Hybridization (SSH) was used to selectively identify differentially expressed genes in hemocytes exposed to V.

Differential gene expression of gamma-actin, Toll-like receptor 2 (TLR-2) and interleukin-1 receptor-associated kinase 4 (IRAK-4) in Mya arenaria haemocytes induced by in vivo infections with two Vibrio splendidus strains.

Immune function gene expression in Mya arenaria haemocytes was evaluated following in vivo infection with Vibrio splendidus LGP32-GFP and 7SHRW. Elongation factor 1alpha (EF-1alpha) with 2 (EF-2), after challenge with LGP32-GFP, and EF-1alpha with the ribosomal protein S-18, after challenge with 7SHRW, were found to be the most stable housekeeping genes. Using these internal controls and comparing the regulation induced by both strains, up-regulation of gamma-actin, down-regulation of TLR-2 and up-regulation of IRAK-4 was significantly higher after challenge with LGP32-GFP (p<0.

Changes induced by two strains of Vibrio splendidus in haemocyte subpopulations of Mya arenaria, detected by flow cytometry with LysoTracker.

Flow-cytometric characterisation of bivalve haemocytes is usually performed by light-scatter profiles based on size and complexity of the cells. Additional means of characterisation such as specific fluorescent dyes are not commonly used to discriminate cell subpopulations in challenged and unchallenged haemocytes. In the present study, we characterise the changes in haemocyte subpopulations of soft-shell clam Mya arenaria induced by in vivo challenge with 2 strains of Vibrio splendidus by using a fluorescent probe.

Differential in vivo response of soft-shell clam hemocytes against two strains of Vibrio splendidus: changes in cell structure, numbers and adherence.

Host-pathogen interaction models in aquatic species are useful tools for understanding the pathogenicity of diseases in cultured and wild populations. In this study we report the differential in vivo response of soft-shell clam (Mya arenaria) hemocytes against two strains of Vibrio splendidus. Responses were measured 24h after injecting into the posterior adductor muscle either an endemic wild-type strain (7SHRW) or a strain associated with oyster mortalities (LGP32-GFP).

Potential link between exposure to fungicides chlorothalonil and mancozeb and haemic neoplasia development in the soft-shell clam Mya arenaria: a laboratory experiment.

The aetiology of haemic neoplasia (HN) is unknown, so far but many causative factors are suggested such as viral, pollution and genetics. The aim of this study was to determine if, under chronic exposure, two major pesticides (chlorothalonil and mancozeb) which are used in potato production could induce HN in soft-shell clams (Mya arenaria). Short-term experiments with acute exposure were also performed.

Selection and evaluation of housekeeping genes for haemocytes of soft-shell clams (Mya arenaria) challenged with Vibrio splendidus.

Gene expression studies have opened a tremendous field of investigation in biological research over the last decades. Expression of genes is most frequently quantified by real time PCR (RT-qPCR), as this method has proven to be highly sensitive. One of the critical steps, however, in comparing transcription profiles is the availability of selected housekeeping genes.

Immunophenotyping of Mya arenaria neoplastic hemocytes using propidium iodide and a specific monoclonal antibody by flow cytometry.

Disseminated neoplasia (DN) is a disorder referred to as hemic neoplasia (HN) in the soft-shell clam Mya arenaria. Traditionally, diagnosis is performed by hematocytology or histology. The intensity of the disease is generally given as the percentage of transformed neoplastic cells out of total number of hemocytes.

Assessment of haemic neoplasia in different soft shell clam Mya arenaria populations from eastern Canada by flow cytometry.

Diagnosis of haemic neoplasia (HN) in the soft shell clam, Mya arenaria, is often achieved by hematocytology and histology. Since neoplastic cells display tetraploid DNA contents, haemocyte cell cycle analysis was developed for use as a diagnosis tool. The aim of this study was to assess the application of a flow cytometry procedure of cell cycle analysis established for the common cockle, to clams and to evaluate different thresholds of value for the percentage of tetraploid cells for establishing HN disease status of individual clams and clam populations.

First report on histology and ultrastructure of an intrahemocytic paramyxean parasite (IPP) from tunicate Halocynthia roretzi in Korea.

In 2004, epizootiological studies were conducted on mass mortalities of tunicates Halocynthia roretzi in Goje, Korea. The clinical characteristics of infected H. roretzi were weakness of the tunic, loss of elasticity, and finally death involving a rupture of the tunic.

Molecular characterisation of an Australian isolate of Bonamia exitiosa.

An Australian (New South Wales) isolate of Bonamia was characterised at the molecular level by sequencing the 18S-ITS-1 region of the small subunit rRNA operon obtained from flat oysters Ostrea angasi shown to be infected by histological examination. Sequence data alignment with homologous genes from 2 other isolates of Bonamia (New Zealand and France) revealed high levels of nucleotide identity with both isolates. However, the Australian Bonamia is shown to be more closely related to the New Zealand isolate, suggesting the existence of an oceanic subgroup of Bonamia.

Development of a TaqMan PCR assay for the detection of Bonamia species.

The development of molecular diagnostic assays with increased sensitivity compared with conventional histological techniques is highly desirable for effective management of bonamiosis in cultured oyster stocks and wild populations. A real-time TaqMan PCR assay was developed for the specific detection of Bonamia species in infected oyster tissues. The TaqMan assay was shown to be significantly more sensitive than histopathology.

Screening of Vibrio isolates to develop an experimental infection model in the Pacific oyster Crassostrea gigas.

In an attempt to develop a reproducible experimental model of bacterial infection in Crassostrea gigas, oysters taken from very localised sub-populations suffering natural mortality outbreaks were used in cohabitation trials under laboratory conditions. From these trials, a collection of Vibrio strains was isolated from moribund and healthy oysters. In a second step, strains were experimentally tested for virulence by means of injection into healthy oysters.

Prevalence and infection intensity of the ovarian parasite Marteilioides chungmuensis during an annual reproductive cycle of the oyster Crassostrea gigas.

The occurrence of Marteilioides chungmuensis, a protozoan paramyxean parasite in the reproductive system of the Pacific oyster Crassostrea gigas, was observed at Gosung Bay, Korea. Seasonal variation in gonad development was investigated in a suspended cultured oyster population. Gametogenesis began in February and first-spawning was observed between mid and late June when surface water temperature reached 22 to 25 degrees C.

Molecular detection of the oyster parasite Mikrocytos mackini, and a preliminary phylogenetic analysis.

The protistan parasite Mikrocytos mackini, the causative agent of Denman Island disease in the oyster Crassostrea gigas in British Columbia, Canada, is of wide concern because it can infect other oyster species and because its life cycle, mode of transmission, and origins are unknown. PCR and fluorescent in situ hybridization (FISH) assays were developed for M. mackini, the PCR assay was validated against standard histopathological diagnosis, and a preliminary phylogenetic analysis of the M.