Evidence of reduced viremia, pathogenicity and vector competence in a re-emerging European strain of bluetongue virus serotype 8 in sheep

The outbreak of bluetongue virus (BTV) serotype 8 (BTV-8) during 2006-2009 in Europe was the most costly epidemic of the virus in recorded history. In 2015, a BTV-8 strain re-emerged in France which has continued to circulate since then. To examine anecdotal reports of reduced pathogenicity and transmission efficiency, we investigated the infection kinetics of a 2007 UK BTV-8 strain alongside the re-emerging BTV-8 strain isolated from France in 2017. Two groups of eight BTV-naïve British mule sheep were inoculated with 5.75 log₁₀ TCID₅₀ /ml of either BTV-8 strain. BTV RNA was detected by 2 dpi in both groups with peak viraemia occurring between 5-9 dpi. A significantly greater amount of BTV RNA was detected in sheep infected with the 2007 strain (6.0-8.8 log₁₀ genome copies/ml) than the re-emerging BTV-8 strain (2.9-7.9 log₁₀ genome copies/ml). All infected sheep developed BTV-specific antibodies by 9 dpi. BTV was isolated from 2 dpi to 12 dpi for 2007 BTV-8-inoculated sheep and from 5 to 10 dpi for sheep inoculated with the remerging BTV-8. In Culicoides sonorensis feeding on the sheep over the period 7-12 dpi, vector competence was significantly higher for the 2007 strain than the re-emerging strain. Both the proportion of animals showing moderate (as opposed to mild or no) clinical disease (6/8 vs. 1/8) and the overall clinical scores (median 5.25 vs. 3) were significantly higher in sheep infected with the 2007 strain, compared to those infected with the re-emerging strain. However, one sheep infected with the re-emerging strain was euthanized at 16 dpi having developed severe lameness. This highlights the potential of the re-emerging BTV-8 to still cause illness in naïve ruminants with concurrent costs to the livestock industry.

Context-produced increase in visibility

It has not been clearly shown that context (e.g., three lines of a square) increases the visibility of a feature (e.g., the fourth line of the same square). To investigate this possibility, four sets of context+feature, context, feature, and BLANK (empty field) stimuli were used. For three out of the four sets, the context+feature stimulus was less likely to be falsely identified as the context and BLANK stimuli (i.e., the stimuli without the feature) than was the feature stimulus. For the same three sets, discriminating between the context+feature and context stimuli produced fewer false identifications (FIs) than discriminating between the feature and BLANK stimuli.

THE CONCLUSION

the context components of context+feature stimuli increased the visibility of the feature components of the same stimuli.

Health effects classification and its role in the derivation of minimal risk levels: developmental effects

Agency for Toxic Substances and Disease Registry (ATSDR) utilizes chemical-specific minimal risk levels (MRLs) to assist in evaluating the public health risk associated with exposure to hazardous substances. The MRLs are derived based on the health effects data compiled from current literature searches and presented in ATSDR's toxicological profiles. Health effects are categorized according to their degree of severity (e.g., serious, less serious, minimal, and not adverse). This evaluation is important, because each respective category can be assigned a different amount of uncertainty, thus affecting the final value of the calculated MRL. From the total of 272 MRLs derived as of December 1997, 21 were based on developmental effects. ATSDR's ranking of developmental health effects as described in the Guidance for Developing Toxicological Profiles and specific examples of how the categorized health effects were used in MRL derivations are provided in this paper.

Identification and characterization of epizootic hemorrhagic disease virus serotype 6 in cattle co-infected with bluetongue virus in Trinidad, West Indies

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Epizootic haemorrhagic disease virus serotype 6 (EHDV-6) is circulating in Trinidad.

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EHDV is infecting cattle at a slower rate than BTV.

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EHDV appears to have a faster viral evolution rate than BTV.

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The EHDV-6 Trinidad strain (VP-2) falls within the eastern topotype clade that is likely to have originated from Australia.

Epizootic hemorrhagic disease virus (EHDV) is an economically important virus that can cause severe clinical disease in deer and to a lesser extent cattle. This study set out to determine and characterize which EHDV serotypes were circulating in Trinidad. Serum and whole blood samples were collected monthly for six months from a cohort of cattle imported to Trinidad from the USA. Results revealed that all the cattle seroconverted to EHDV within six months of their arrival, with EHDV RNA being detected in the samples just prior to antibodies, as expected. Serotyping assays revealed that a single serotype (EHDV-6) was circulating in the cattle. Sequencing of the surface viral protein (VP2) of EHDV-6, followed by phylogenetic analysis, revealed that the Trinidad EHDV-6 strain was closely related to EHDV-6 viruses found in Guadeloupe (2010), Martinique (2010) and USA (2006), with 96–97.2% nucleotide identity. The Trinidad EHDV-6 VP-2 shared 97.2% identity with the Australian EHDV-6 prototype strain, classifying it within the eastern topotype clade. Bayesian coalescent analysis support Australia as the most probable source for the EHDV-6 VP2 sequences in the Americas and Caribbean region and suggests that the they diverged from the Australian prototype strain around 1966 (95% HPD 1941–1979).

Evaluation of the Efficacy of Commercial Disinfectants against African Swine Fever Virus

African swine fever (ASF) is an economically important disease due to high morbidity and mortality rates and the ability to affect all ages and breeds of pigs. Biosecurity measures to prevent the spread of the causative agent, African swine fever virus (ASFV), include prescriptive cleaning and disinfection procedures. The aim of this study was to establish the biocidal effects of twenty-four commercially available disinfectants including oxidizing agents, acids, aldehydes, formic acids, phenol, and mixed-class chemistries against ASFV. The products were prepared according to the manufacturer's instructions and a suspension assay was performed with ASFV strain, BA71V using Vero cells (African green monkey cells) to test efficacy in reducing ASFV infection of cells. Generally, disinfectants containing formic acid and phenolic compounds, as well as oxidizing agents reduced viral titers of ASFV by over 4 log₁₀ at temperatures ranging from 4 °C to 20 °C. Hydrogen peroxide, aldehyde, and quaternary ammonium compounds containing disinfectants were cytotoxic, limiting the detection of viral infectivity reductions to less than 4 log₁₀. These preliminary results can be used to target research on disinfectants which contain active ingredients with known efficacy against ASFV under conditions recommended for the country where their use will be applied.

BTV-14 Infection in Sheep Elicits Viraemia with Mild Clinical Symptoms

In 2011, Bluetongue virus serotype 14 (BTV-14) was detected in Russia during routine surveillance, and was subsequently found in a number of European countries. The strain had high sequence similarity to a BTV-14 vaccine strain. We aimed to determine the risk of this BTV-14 strain causing disease in a UK sheep breed. Four Poll Dorset sheep were infected with a Polish isolate of BTV-14 and infection kinetics were monitored over 28 days. BTV RNA was detected in EDTA blood by 4 days post-infection (dpi) and remained detectable at 28 days post-infection (dpi). Peak viraemia occurred at 6 and 7 dpi with Ct values ranging between 24.6 and 27.3 in all infected animals. BTV antibodies were detected by 10 dpi using a commercial ELISA and neutralising antibodies were detected from 10 dpi. BTV was isolated between 6 and 12 dpi. All infected sheep developed mild clinical signs such as reddening of conjunctiva and mucosal membranes, with one sheep demonstrating more overt clinical signs. Two uninoculated control animals remained clinically healthy and did not have detectable BTV RNA or antibodies. The overall mild clinical symptoms caused by this BTV-14 in this highly susceptible sheep breed were in accordance with the asymptomatic infections observed in the affected countries.

Liquid Chromatographic Determination of Glyphosate in Water-Soluble Granular Formulations: Collaborative Study

A liquid chromatographic (LC) method for the determination of glyphosate in various water-soluble granular formulations was tested by 28 laboratories. Samples were dissolved in mobile phase and injected directly into an LC system with a 25 cm SAX column and a mobile phase of 96% aqueous buffer solution, 0.0062M KH2PO4, and 4% methanol. Detection was by UV absorption at 195 nm. Manual or automated injections were made via fixed-volume loops. Calculations were based on peak area comparisons with external standards. The collaborative study analyzed 5 matched pairs of 4 water-soluble granular formulations, with one determination per sample. The study generated 138 matched pairs, which were analyzed by using the AOAC spreadsheet and Youden’s matched-pair calculations. Coefficients of variation for the 4 formulations ranged from 0.65 to 1.37%. The LC method for the determination of glyphosate in water-soluble granular formulations has been adopted first action by AOAC INTERNATIONAL.

Assimilation in visibility: additional evidence

The present research tested the theory that a less visible target increases in similarity to a more visible simultaneous context, and that therefore the target increases in visibility. This assimilation-in-visibility theory was tested using context + targets that were either 3-line brackets or 2-line right angles, contexts and targets that were the component lines of these context + targets, with the target always the identical single top line. Experiments with a total of 204 participants indicated that the 3-line context + targets resulted in better context + target versus context discriminations than target versus background discriminations than did the 2-line context + targets. This was so for both over-all errors and misses but not false alarms. It is concluded that only the 3-line context + targets increased the visibility of the 1-line target. Additional analysis indicated that the 2-line contexts of the 3-line context + targets were more visible than all the 1-line stimuli. So, the 1-line target assimilated to a simultaneous more visible 2-line context and thereby increased in visibility, thus improving the context + target versus context discrimination. This support for the assimilation-in-visibility theory is of interest because assimilation and contrast in visibility may play a large role in perception.

Foot-and-mouth disease viruses of the O/ME-SA/Ind-2001e sublineage in Pakistan

The presence of foot-and-mouth disease virus (FMDV) of the O/ME-SA/Ind-2001e sublineage within Pakistan was initially detected in two samples collected during 2019. Analysis of further serotype O FMDVs responsible for disease outbreaks in 2019-2020 in the country has now identified the spread of this sublineage to 10 districts within two separate provinces in North-Eastern and North-Western Pakistan. Phylogenetic analysis indicates that these viruses are closely related to those circulating in Bhutan, Nepal and India. The VP1 coding sequences of these viruses from Pakistan belong to three distinct clusters, which may indicate multiple introductions of this virus sublineage, although the routes of introduction are unknown. Vaccine matching studies against O1 Manisa, O 3039 and O TUR/5/2009 support the suitability of existing vaccine strains to control current field outbreaks, but further studies are warranted to monitor the spread and evolution of the O/ME-SA/Ind-2001e sublineage in the region. (145 words).

Detection of foot-and-mouth disease viruses from the A/AFRICA/G-I genotype in the Sultanate of Oman

Rapid identification and characterization of circulating foot-and-mouth disease virus (FMDV) strains is crucial for effective disease control. In Oman, a few serological and molecular studies have been conducted to identify the strains of FMDV responsible for the outbreaks that have been occurring within the country. In this study, 13 oral epithelial tissue samples from cattle were collected from suspected cases of FMD in Ash Sharqiyah North, Al Batinah North, Dhofar and Ad Dhakhyilia governorates of Oman between 2018 and 2021. FMDV RNA was detected in all samples by real-time RT-PCR and viruses were isolated after one- or two-blind passages in the porcine Instituto Biologico-Rim Suino-2 cell line. Antigen capture ELISA characterized all isolates as serotype A and VP1 phylogenetic analysis placed all sequences within a single clade of the G-I genotype within the A/AFRICA topotype. These sequences shared the closest nucleotide identities to viruses circulating in Bahrain in 2021 (93.5% to 99.5%) and Kenya in 2017 (93.4% to 99.1%). To the best of our knowledge, this is the first time that A/AFRICA/G-I viruses have been detected in Oman. Together with the closely related viruses detected recently in Bahrain, these findings reinforce the importance of deploying effective quarantine control measures to minimize the risks of transboundary transmission of FMD associated with the importation of cattle from East Africa.

Genome Sequence of a Foot-and-Mouth Disease Virus Detected in Indonesia in 2022

During 2022, outbreaks of foot-and-mouth disease (FMD) were reported across the islands of Indonesia, a country that had previously maintained an FMD-free (without vaccination) status since 1990. This report describes the near-complete genome sequence of a representative FMD virus collected from these cases belonging to the O/ME-SA/Ind-2001e lineage.

Eastern Africa Origin of SAT2 Topotype XIV Foot-and-Mouth Disease Virus Outbreaks, Western Asia, 2023

We describe detection of SAT2 topotype XIV foot-and-mouth disease viruses in western Asia during 2022-2023. Sequences show the viruses originated in eastern Africa and were introduced into western Asia on >1 occasion. The rapid spread in naive animals highlights risks for onward transmission and potential endemicity in Asia.

Molecular Epidemiology of Foot-and-Mouth Disease Viruses in the Emirate of Abu Dhabi, United Arab Emirates

Foot-and-mouth disease (FMD) is an endemic disease in the United Arab Emirates (UAE) in both wild and domestic animals. Despite this, no systematic FMD outbreak investigation accompanied by molecular characterisation of FMD viruses (FMDVs) in small ruminants or cattle has been performed, and only a single report that describes sequences for FMDVs in wildlife from the Emirate has been published. In this study, FMD outbreaks that occurred in 2021 in five animal farms and one animal market in the Emirate of Abu Dhabi were investigated. Cases involved sheep, goats, and cattle, as well as Arabian oryx (Oryx leucoryx). Twelve samples were positive for FMDV via RT-qPCR, and four samples (Arabian oryx n = 1, goat n = 2, and sheep n = 1) were successfully genotyped using VP1 nucleotide sequencing. These sequences shared 88~98% identity and were classified within the serotype O, Middle East-South Asia topotype (O/ME-SA). Phylogenetic analysis revealed that the Arabian oryx isolate (UAE/2/2021) belonged to the PanAsia-2 lineage, the ANT-10 sublineage, and was closely related to the FMDVs recently detected in neighbouring countries. The FMDV isolates from goats (UAE/10/2021 and UAE/11/2021) and from sheep (UAE/14/2021) formed a monophyletic cluster within the SA-2018 lineage that contained viruses from Bangladesh, India, and Sri Lanka. This is the first study describing the circulation of the FMDV O/ME-SA/SA-2018 sublineage in the UAE. These data shed light on the epidemiology of FMD in the UAE and motivate further systematic epidemiological studies and genomic sequencing to enhance the ongoing national animal health FMD control plan.

Foot-and-mouth disease virus O/ME-SA/SA-2018: A new emerging threat posed by viruses circulating in Asia?

In 2018, a novel lineage of foot-and-mouth disease virus (FMDV) termed O/ME-SA/SA-2018 was identified in India, which subsequently spread into neighbouring countries (Nepal, Bangladesh and Sri Lanka). Since then, incursions of this lineage have occurred in the Middle East, beyond its usual epidemiological distribution. Using sequence data derived from field cases, this paper reconstructs the evolutionary history of the O/ME-SA/SA-2018 lineage, presents vaccine matching data for six commercially available FMD vaccines, and describes a novel lineage-specific RT-PCR assay which can be used to help detect field cases due this emerging lineage. Further surveillance studies are warranted to understand the distribution of this virus in Asian countries.