Transcriptome-level assessment of the impact of deformed wing virus on honey bee larvae.

Deformed wing virus (DWV) prevalence is high in honey bee (Apis mellifera) populations. The virus infects honey bees through vertical and horizontal transmission, leading to behavioural changes, wing deformity, and early mortality. To better understand the impacts of viral infection in the larval stage of honey bees, artificially reared honey bee larvae were infected with DWV (1.55 × 1010 copies/per larva). No significant mortality occurred in infected honey bee larvae, while the survival rates decreased significantly at the pupal stage. Examination of DWV replication revealed that viral replication began at 2 days post inoculation (d.p.i.), increased dramatically to 4 d.p.i., and then continuously increased in the pupal stage. To better understand the impact of DWV on the larval stage, DWV-infected and control groups were subjected to transcriptomic analysis at 4 d.p.i. Two hundred fifty-five differentially expressed genes (DEGs) (fold change ≥ 2 or ≤ -2) were identified. Of these DEGs, 168 genes were downregulated, and 87 genes were upregulated. Gene Ontology (GO) analysis showed that 141 DEGs (55.3%) were categorized into molecular functions, cellular components and biological processes. One hundred eleven genes (38 upregulated and 73 downregulated) were annotated by KO (KEGG Orthology) pathway mapping and involved metabolic pathways, biosynthesis of secondary metabolites and glycine, serine and threonine metabolism pathways. Validation of DEGs was performed, and the related gene expression levels showed a similar tendency to the DEG predictions at 4 d.p.i.; cell wall integrity and stress response component 1 (wsc1), cuticular protein and myo-inositol 2-dehydrogenase (iolG) were significantly upregulated, and small conductance calcium-activated potassium channel protein (SK) was significantly downregulated at 4 d.p.i. Related gene expression levels at different d.p.i. revealed that these DEGs were significantly regulated from the larval stage to the pupal stage, indicating the potential impacts of gene expression levels from the larval to the pupal stages. Taken together, DWV infection in the honey bee larval stage potentially influences the gene expression levels from larvae to pupae and reduces the survival rate of the pupal stage. This information emphasizes the consequences of DWV prevalence in honey bee larvae for apiculture.

The role of a mechanistic host in maintaining arctic rabies variant distributions: Assessment of functional genetic diversity in Alaskan red fox (Vulpes vulpes).

Populations are exposed to different types and strains of pathogens across heterogeneous landscapes, where local interactions between host and pathogen may present reciprocal selective forces leading to correlated patterns of spatial genetic structure. Understanding these coevolutionary patterns provides insight into mechanisms of disease spread and maintenance. Arctic rabies (AR) is a lethal disease with viral variants that occupy distinct geographic distributions across North America and Europe. Red fox (Vulpes vulpes) are a highly susceptible AR host, whose range overlaps both geographically distinct AR strains and regions where AR is absent. It is unclear if genetic structure exists among red fox populations relative to the presence/absence of AR or the spatial distribution of AR variants. Acquiring these data may enhance our understanding of the role of red fox in AR maintenance/spread and inform disease control strategies. Using a genotyping-by-sequencing assay targeting 116 genomic regions of immunogenetic relevance, we screened for sequence variation among red fox populations from Alaska and an outgroup from Ontario, including areas with different AR variants, and regions where the disease was absent. Presumed neutral SNP data from the assay found negligible levels of neutral genetic structure among Alaskan populations. The immunogenetically-associated data identified 30 outlier SNPs supporting weak to moderate genetic structure between regions with and without AR in Alaska. The outliers included SNPs with the potential to cause missense mutations within several toll-like receptor genes that have been associated with AR outcome. In contrast, there was a lack of genetic structure between regions with different AR variants. Combined, we interpret these data to suggest red fox populations respond differently to the presence of AR, but not AR variants. This research increases our understanding of AR dynamics in the Arctic, where host/disease patterns are undergoing flux in a rapidly changing Arctic landscape, including the continued northward expansion of red fox into regions previously predominated by the arctic fox (Vulpes lagopus).

Development of a cost-efficient micro-detection slide system for the detection of multiple shrimp pathogens.

In view of the current demand for rapid detection and identification of pathogens, point-of-care testing (POCT) with fast portability, low consumption, and increased sensitivity and specificity has become more and more popular. The emerging nucleic acid isothermal amplification technology (NAIAT) has shown potential advantages in the development of rapid microbial detection. In this study, a micro-detection slide system was developed based on the NAIAT of various nucleic acids of shrimp pathogens. The system included a micro-detection slide with 48 identical detecting cells precoated with all detection reagents, except the sample template. The process of producing the micro-detection slides mainly combined super-hydrophobic/super-oleophobic and super-hydrophilic materials to obtain separated spaces for detection, and aerosol pollution was eliminated in the form of water-in-oil. The micro-detection slide system was capable of simultaneously detecting 4 groups of samples and 8 important shrimp pathogens and is a relatively low-cost, portable, and high-throughput nucleic acid (RNA and DNA) detection technology. The establishment of this technology will provide key technical support for the construction of biosecurity systems for healthy shrimp culture.

Public health impact of reemergence of rabies, New York.

This report summarizes the spread of a raccoon rabies epizootic into New York in the 1990s, the species of animals affected, and human postexposure treatments (PET). A total of 57,008 specimens were submitted to the state laboratory from 1993 to 1998; 8,858 (16%) animals were confirmed rabid, with raccoons the most common species (75%). After exposure to 11,769 animals, 18,238 (45%) persons received PET, mostly because of contact with saliva or nervous tissue. We analyzed expenditure reports to estimate the cost of rabies prevention activities. An estimated $13.9 million was spent in New York State to prevent rabies from 1993 to 1998. Traditional prevention methods such as vaccinating pets, avoiding wildlife, and verifying an animal's rabies status must be continued to reduce costly PET. To reduce rabid animals, exposures, and costs, oral vaccination of wildlife should also be considered.

Engineering control of airborne disease transmission in animal laboratories.

We here present a review of the problem of controlling airborne disease transmission in animal research facilities, with emphasis on engineering design and air-treatment technologies. Dilution ventilation, pressurization control, source control, and air disinfection and removal systems are reviewed, and analytical studies on the effects of dilution ventilation, filtration, and ultraviolet germicidal irradiation are summarized. In addition, we discuss practical problems common to laboratory facilities and present a database of potential airborne pathogens and allergens that can be transmitted between humans and animals. We offer some conclusions regarding the design and selection of available technologies and components and provide cost estimates for various air-cleaning systems.

A review of the economics of the prevention and control of rabies. Part 2: Rabies in dogs, livestock and wildlife.

Although rabies in domestic and wild animals represents a significant threat to public health and can cause economic losses among livestock, there are very few studies that examine the economics of rabies in animals. The literature that does exist can be characterised as poorly documented estimates of costs, with insufficient information to allow replication of the analyses. Most papers have numerous 'violations' of the standard recommended procedures for assessing burden of disease and the cost and benefits of interventions. For example, most studies do not distinguish between financial charges and true economic costs. Further, despite the fact that controlling rabies in animal populations is often a multi-year task, only a few papers contain a multi-year framework, complete with discounting of future costs and benefits. Globally, dog-transmitted rabies represents the largest threat to human health. In order to prevent the transmission of rabies in a dog population, it is theoretically necessary to vaccinate a minimum of 60 to 70% of the dogs. Even countries with potentially sufficient resources, however, do not often meet and sustain these rates. One reason for such failure might be that individual dog owners might feel that it is too expensive to vaccinate their pets. Recent estimates in the US of the cost of vaccinating dogs range from $US16 to $US24 per dog. In developing countries, estimates range from $US0.52 in Thailand, to $US1.19 in the Philippines, to $US2.70 in Malawi. None of these estimates include indirect costs accured by the pet owners. Lethal methods of dog population control are even more expensive, and attempting to control rabies by reducing dog populations has not worked for any extended period. Rabies in livestock is often reported, but the impact in the US and most developed countries appears relatively small. Vampire bat-transmitted rabies in Latin America appears to be the most serious rabies problem in livestock. The largest cost due to wildlife rabies is the cost of vaccinating domestic animals, both large and small. In the US, domestic animals face multiple sources of wildlife rabies. Attributing the entire cost of vaccinating domestic animals to 1 species can result in the over estimation of the benefits of immunising a given wildlife population via vaccine-laden baits. For example, despite a definite decline in the number of rabid foxes, it has been difficult to obtain the promised benefits of using oral vaccines in Europe to control fox rabies. Other authors maintain that the use of oral vaccines to control fox rabies is cost beneficial, but there are no convincing data supporting that claim. Additionally, vaccinating raccoons with an oral vaccine requires approximately 4 times more vaccine-laden baits vaccinating foxes, which makes it highly questionable if it would be cost beneficial to use oral vaccine to attempt raccoon rabies elimination in areas where it is already enzootic. The economics of using oral vaccines to prevent raccoon rabies invading uninfected areas has yet to be examined.