Optimizing surveillance for early disease detection: Expert guidance for Ostreid herpesvirus surveillance design and system sensitivity calculation.

To keep pace with rising opportunities for disease emergence and spread, surveillance in aquaculture must enable the early detection of both known and new pathogens. Conventional surveillance systems (designed to provide proof of disease freedom) may not support detection outside of periodic sampling windows, leaving substantial blind spots to pathogens that emerge in other times and places. To address this problem, we organized an expert panel to envision optimal systems for early disease detection, focusing on Ostreid herpesvirus 1 (OsHV-1), a pathogen of panzootic consequence to oyster industries. The panel followed an integrative group process to identify and weight surveillance system traits perceived as critical to the early detection of OsHV-1. Results offer a road map with fourteen factors to consider when building surveillance systems geared to early detection; factor weights can be used by planners and analysts to compare the relative value of different designs or enhancements. The results were also used to build a simple, but replicable, model estimating the system sensitivity (SSe) of observational surveillance and, in turn, the confidence in disease freedom that negative reporting can provide. Findings suggest that optimally designed observational systems can contribute substantially to both early detection and disease freedom confidence. In contrast, active surveillance as a singular system is likely insufficient for early detection. The strongest systems combined active with observational surveillance and engaged joint industry and government involvement: results suggest that effective partnerships can generate highly sensitive systems, whereas ineffective partnerships may seriously erode early detection capability. Given the costs of routine testing, and the value (via averted losses) of early detection, we conclude that observational surveillance is an important and potentially very effective tool for health management and disease prevention on oyster farms, but one that demands careful planning and participation. This evaluation centered on OsHV-1 detection in farmed oyster populations. However, many of the features likely generalize to other pathogens and settings, with the important caveat that the pathogens need to manifest via morbidity or mortality events in the species, life stages and environments under observation.

Transboundary animal diseases as re-emerging threats - Impact on one health.

Transboundary animal diseases are those that can move through a population of animals and cause considerable economic and societal harm. Many have high mortality, and in low-income areas, can quickly destroy herds and flocks of agricultural animals. Although much of One Health, which sits at the intersection of human, animal, and environmental health, focuses on the zoonotic diseases, in fact transboundary animal diseases can harm both humans and the environment through robbing communities of livelihoods and nutrition, and creating environmental contamination through extensive carcass disposal requirements. Transboundary animal diseases continue to circulate in the world, predominantly in low-income regions or in areas with less than optimal biosecurity. This paper will review three prominent emerging and re-emerging transboundary animal diseases, describing their pathology and diagnostics, as well as economic and food security impacts, which are substantial. Attention to these devastating diseases should be a One Health priority.

The socioeconomic factors surrounding the initial emergence of peste des petits ruminants in Kenya, Uganda, and Tanzania from 2006 through 2008.

Peste des petits ruminants (PPR) is a devastating disease of small ruminants that significantly hinders productivity in endemic areas. Kenya, Uganda and Tanzania reported their first cases in each country between 2006 and 2008 despite the disease being present in the region (Ethiopia and Sudan) since the 1990s. The time leading up to the outbreaks involved refugee movements, drought, civil unrest, and resulted in increased animal mingling, movement and density in these regions. Refugee camps with animal source food demands and a robust informal economy further added to the development of animal mingling and movement as well. Once introduced, common pastoral migration lands and trade routes likely transported the disease throughout the region. This paper highlights why trade routes, refugee camps and areas of animal crowding during droughts should be targeted for interventions, monitoring and surveillance as part of PPR control in a region.

Tagging of Weakly Expressed Toxoplasma gondii Calcium-Related Genes with High-Affinity Tags.

Calcium ions regulate a diversity of cellular functions in all eukaryotes. The cytosolic Ca2+ concentration is tightly regulated at the physiological cytosolic concentration of 50-100 nm. The Toxoplasma gondii genome predicts the presence of several genes encoding potential Ca2+ channels, pumps, and transporters. Many of these genes are weakly expressed and likely tightly regulated due to their potential impact to the physiology of the cell. Endogenous tagging has been widely used to localize proteins in T. gondii but low level of expression of many of them makes visualization of tags difficult and sometimes impossible. The use of high-performance tags for labeling proteins expressed at low level is ideal for investigating the localization of these gene products. We designed a Carboxy-terminus tagging plasmid containing the previously characterized "spaghetti monster-HA" (smHA) or "spaghetti monster-MYC" (smMYC) tags. These tags consist of 10 copies of a single epitope (HA or MYC) inserted into a darkened green fluorescence protein scaffold. We localized six proteins of various levels of expression. Clonal lines were isolated and validated by PCR, western blot, and immunofluorescence analyses. Some gene products were only visible when tagged with smHA and in one case the smHA revealed a novel localization previously undetected.