World Organisation For Animal Health Research Articles

Lumpy Skin Disease: An Emerging Concern in Pakistan and its Impact on National Economic Loss

Lumpy Skin Disease (LSD), an emerging viral infection of cattle and buffalo, poses significant challenges to the livestock industry in Pakistan. Symptoms of this disease include enlarged appearance of lumps, high fever, discharge from the eyes and nose, and loss of appetite. The incubation period of this virus in cattle is approximately 28 days, as per the report of the Food and Agriculture Organization (FAO). This viral infection spreads through direct contact among herds. The World Organization for Animal Health (WOAH) and the FAO both warn that the spread of illnesses could lead to serious economic losses. A considerable financial loss in this industry is due to the mortality rate, reduced milk and meat production rate, and increasing management and treatment expenses. Generally, the best administrative approach to treating this disease is vaccination, which is also an economically effective strategy. This review aims to provide insights into the symptoms, risk factors, control, and disease administrative strategies, economic loss associated with Lumpy Skin Disease, and the potential role of vaccination in future disease management strategies.

Development and evaluation of time-resolved rapid immunofluorescence test for detection of TSOL18 specific antibody in porcine cysticercosis infections

BackgroundPorcine cysticercosis, a serious zoonotic parasitic disease, is caused by the larvae of Taenia solium and has been acknowledged by the World Organization for Animal Health. The current detection methods of Cysticercus cellulosae cannot meet the needs of large-scale and rapid detection in the field. We hypothesized that the immunofluorescence chromatography test strip (ICS) for detecting Cysticercus cellulosae, according to optimization of a series of reaction systems was conducted, and sensitivity, specificity, and stability testing, and was finally compared with ELISA. This method utilizes Eu3+-labeled time-resolved fluorescent microspheres (TRFM) coupled with TSOL18 antigen to detect TSOL18 antibodies in infected pig sera.ResultsICS and autopsy have highly consistent diagnostic results (n = 133), as determined by Cohen’s κ analysis (κ = 0.925). And the results showed that the proposed ICS are high sensitivity (0.9459) with specificity (0.9792). The ICS was unable to detect positive samples of other parasites. It can be stored for at least six months at 4℃.ConclusionsIn summary, we established a TRFM-ICS method with higher sensitivity and specificity than indirect ELISA. Results obtained from serum samples can be read within 10 min, indicating a rapid, user-friendly test suitable for large-scale field detection.

Animal sentience: The science and its implications, with particular reference to farmed animals

AbstractThere is an increasing amount of scientific research into animal sentience. Many scientists are studying the cognitive, emotional, and communicative capacities of a range of animals. The results of this research have led to a number of legal recognitions of the sentience of a range of animals. In 1997, the European Union (EU) gave legal recognition to the sentience of animals and updated and elevated this recognition in the Treaty of Lisbon. Other countries and states as well as the World Organization for Animal Health (WOAH, formerly OIE) have followed it. Scientists are increasingly acknowledging that sentience and emotion have arisen in a wide range of species. Research now emphasizes that there is an extraordinary variation in how different animal species (such as mammals, birds, fish, or insects) perceive the world and their environment. This paper looks at the sentience of the main farmed land and aquatic animals and the implications of this for how such animals are bred and housed. The paper concludes that intensive farming systems deprive animals of opportunities for positive emotions, such as play, exploration, social interaction, and feeding to satiation, and stops them from satisfying naturally motivated behaviors. To truly respect animal sentience, production systems should be designed with the animal's characteristics and needs in mind. The authors conclude that regenerative, agroecological, or organic farming systems better protect and respect the sentience of animals leading to less suffering and more opportunities for positive experiences.

Is Artemia susceptible to the microsporidium Ecytonucleospora hepatopenaei (EHP) infection?

Following the three-stage approach of the WOAH (World Organisation for Animal Health) standard on the confirmation of susceptible species to a specific pathogen, Artemia franciscana juveniles were challenged with immersion exposure (IM) in a homogenate suspension of Penaeus vannamei hepatopancreas infected with Ecytonucleospora hepatopenaei (EHP) and per os administration (PO) with chlorella soaked in EHP-infected hepatopancreatic homogenate suspension. Using TaqMan probe-based quantitative PCR, we detected that loads of EHP in A. franciscana juveniles from both the IM and PO groups were about 101 copies/ng-DNA on the 3rd day post-exposure (3 dpe). However, no more EHP was detectable in the challenged A. franciscana juveniles on 7 dpe. Nested PCR targeting the EHP spore wall protein gene did not produce a target band in A. franciscana juveniles on either 3 dpe or 7 dpe. The confirmative evidence of the absence of sustained infection with EHP in the exposed Artemia was substantiated using in situ DIG-labeling-loop-mediated DNA amplification (ISDL) on A. franciscana juvenile sections, which revealed a few weak grey-blue positive signals appeared on 3 dpe but disappeared on 7 dpe. The results indicated that exposure to EHP resulted in the invasion of Artemia in intestinal epithelial cells, but the infection was unable to persist, confirming Artemia is not susceptible to EHP. Therefore, the research countered the assertion of Artemia as a potential EHP reservoir.

The epidemiology and clinical features of post-exposure prophylaxis for rabies: A retrospective study of 9772 cases

BackgroundIn December 2015, the World Health Organization, the World Animal Health Organization, and the Food and Agriculture Organization of the United Nations convened the International Congress on the elimination of rabies in Geneva. How to use epidemiological factors of post-exposure prophylaxis to prevent rabies has become the focus of attention. ObjectiveTo analyze the epidemiological characteristics of 9772 patients with rabies in a four-year period in one hospital, to clarify the outbreak law of rabies and to explore the corresponding prevention and control strategies. MethodsThe epidemiological data of rabies patients were collected from the infectious disease reporting information management system of the hospital from July 2018 to June 2022. The distributional characteristics of 13 influencing factors were analyzed using the chi-square test and linear regression. ResultsThere was a significant correlation between the number of wounds and age, and the numbers of female and male patients were close. People over the age of 44 were more likely to get bites or scratches on their lower extremity (P<0.0001). There was a greater possibility for elderly people to be bitten by dogs (P<0.0001). Dogs preferred to bite or scratch lower limbs (P<0.0001), while cats upper limbs (P<0.0001). Upper limbs were more possibly attacked by animals at home (P<0.0001). There were significant correlations among exposure grade, wound treatment and number of wounds. Conclusions: Lower extremity protection is needed for the elderly and when encountering dogs, and more attention needs to be paid to the upper extremities when encountering cats and household pets, as well as pets that are cute but need to be protected from bites or scratches.

First report of Perkinsus marinus occurrence associated with wild Pacific oysters Crassostrea gigas from the west coast of Korea

This study reports the occurrence of Perkinsus marinus associated with wild Pacific oyster (Crassostrea gigas) specimens collected along the west coast of Korea. Confirmation of P. marinus presence was achieved by conventional PCR using World Organization of Animal Health (WOAH)-recommended primers that specifically targeted regions of the rDNA locus (ITS1, 5.8S, and ITS2). Sequencing of 10 samples revealed two distinct sequences differing by a single base pair, indicating potential haplotype variability. One sequence closely resembled the P. marinus strain found in Maryland, USA, whereas the other exhibited divergence, indicative of species diversity in the Korean strain, as was evident from the haplotype network analysis. Further validation involved the Ray’s Fluid Thioglycollate Medium (RFTM) assay, which initially yielded inconclusive results, possibly due to low infection intensity. Subsequently, RFTM and 2 M NaOH assays conducted on the isolates in the present study, cultured P. marinus cells in standard DMEM/F12 medium, and a positive P. marinus strain (ATCC 50509), revealed characteristic hypnospores of P. marinus upon Lugol’s iodine staining. These comprehensive investigations underscore the conclusive confirmation of P. marinus in Korean waters and mark a significant milestone in our understanding of the distribution and characteristics of this parasite in previously unreported regions.

Development of a novel sensitive single-tube nested PCR assay for the detection of African swine fever virus.

African swine fever (ASF) is a highly fatal and contagious viral disease caused by African swine fever virus (ASFV). It has caused significant economic losses to the swine industry and poses a serious threat to food security worldwide. Diagnostic tests with high sensitivity are essential for the effective management of ASF. Here, we describe a single-tube nested PCR (STN-PCR) assay for the detection of ASFV in which two consecutive amplification steps are carried out within a single tube. Two pairs of primers (outer and inner) were designed to target the p72 gene of ASFV. The primer concentrations, annealing temperatures, and number of amplification cycles were optimized to ensure the consecutive utilization of outer and inner primer pairs during amplification while minimizing the likelihood of amplicon contamination. In comparison with two conventional endpoint PCR assays (one of which is recommended by the World Organization for Animal Health), the newly developed STN-PCR assay demonstrated a 100-fold improvement in the limit of detection (LOD), detecting 100 copies of ASFV genomic DNA, whereas the endpoint PCR assays could detect no fewer than 10,000 copies. The clinical performance of the STN-PCR assay was validated using 95 tissue samples suspected of being positive for ASFV, and the assay showed 100% specificity. A Cohen's kappa value of 0.91 indicated perfect agreement between the assays. This new STN-PCR assay is a potentially valuable tool that will facilitate the control of ASF.

Detection of SARS-CoV-2 Delta Variant (B.1.617.2) in Domestic Dogs and Zoo Tigers in England and Jersey during 2021.

Reverse zoonotic transmission events of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been described since the start of the pandemic, and the World Organisation for Animal Health (WOAH) designated the detection of SARS-CoV-2 in animals a reportable disease. Eighteen domestic and zoo animals in Great Britain and Jersey were tested by APHA for SARS-CoV-2 during 2020-2023. One domestic cat (Felis catus), three domestic dogs (Canis lupus familiaris), and three Amur tigers (Panthera tigris altaica) from a zoo were confirmed positive during 2020-2021 and reported to the WOAH. All seven positive animals were linked with known SARS-CoV-2 positive human contacts. Characterisation of the SARS-CoV-2 variants by genome sequencing indicated that the cat was infected with an early SARS-CoV-2 lineage. The three dogs and three tigers were infected with the SARS-CoV-2 Delta variant of concern (B.1.617.2). The role of non-human species in the onward transmission and emergence of new variants of SARS-CoV-2 remain poorly defined. Continued surveillance of SARS-CoV-2 in relevant domestic and captive animal species with high levels of human contact is important to monitor transmission at the human-animal interface and to assess their role as potential animal reservoirs.

Facing SARS-CoV-2 emergence on the animal health perspective: The role of the World Organisation for Animal Health in preparedness and official reporting of disease occurrence.

Current data suggest that SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) emerged from an animal source. However, to date, there is insufficient scientific evidence to identify the source of SARS-CoV-2 or to explain the original route of transmission to humans. A wide range of mammalian species have been shown to be susceptible to the virus through experimental infection, and in natural environments when in contact with infected humans. The main objective of this work was to provide a summary of the official data shared by countries on SARS-CoV-2 in animals with the World Organisation for Animal Health (WOAH), to highlight the role of WOAH as an international organization in coordinating scientific information actions and to discuss the implications and impact of these activities. Between January 2020 and December 2022, 36 countries in Europe, the Americas, Asia and Africa officially reported SARS-CoV-2 identification in 26 animal species. Affected countries were generally responsive in confirming the pathogen (median of 5 days after onset) and reporting to WOAH (median of 7 days after confirmation). During the pandemic, WOAH, supported by its network of experts, played a crucial role in collecting, analysing and disseminating veterinary scientific information, acting as the reference organization on these issues, thus avoiding misinformation and disinformation. Future perspectives to avoid new emerging threats are discussed.

Postvaccination serosurveillance of foot-and-mouth disease through virus-neutralizing and nonstructural protein antibody tests on pig farms in Taiwan: 2009–2020

The use of virus-neutralizing (VN) and nonstructural protein (NSP) antibody tests in a serosurveillance program for foot-and-mouth disease (FMD) can identify pig herds that are adequately vaccinated, with a high percentage of pigs with VN positive antibody titers; these tests can also help identify pigs with NSP-positivity that have previously been or are currently infected even in vaccinated herds. To identify infected herds and manage infection, the combination of VN and NSP antibody tests was used in Taiwan’s serosurveillance program implemented simultaneously with the compulsory FMD vaccination program. The result was the eradication of FMD: Taiwan was recognized by the World Organization for Animal Health as an FMD-free country without vaccination in 2020. Evaluation of the compulsory vaccination program incorporated in the FMD control program in Taiwan revealed that the vaccine quality was satisfactory and the vaccination program was effective during the period of compulsory vaccination (2010–2017). Sound immunological coverage was achieved, with 89.1% of pigs having VN antibody titers exceeding 1:16 in 2016. This level of immunological coverage would be expected to substantially reduce or prevent FMD transmission, which was borne out by the results of the NSP tests. We identified farms having positive NSP reactors (very low annual prevalence) before the cessation of FMD vaccination in July 2018; however, detailed serological and clinical investigations of pigs of all ages in suspect herds demonstrated that no farms were harboring infected animals after the second half of 2013. Thus, the results revealed no evidence of FMD circulation in the field, and Taiwan regained FMD-free status.

Policy strategies for managing food safety risks associated with climate change and agriculture

Managing food safety risks associated with climate change and agriculture necessitates comprehensive policy strategies to safeguard public health, ensure food security, and sustain agricultural productivity. This review delves into the multifaceted challenges posed by climate change on food safety and explores policy approaches aimed at mitigating these risks. Climate change presents a myriad of challenges to food safety, including altered patterns of precipitation, temperature extremes, and increased occurrences of extreme weather events. These changes impact various stages of the food supply chain, from production to consumption, exacerbating existing food safety risks and introducing new ones. Addressing these challenges requires proactive policy strategies that integrate climate adaptation and food safety management. Policy strategies for managing food safety risks associated with climate change encompass a range of measures aimed at enhancing resilience, promoting sustainable agricultural practices, and strengthening food safety systems. One key approach involves the implementation of climate-smart agriculture (CSA) practices, which aim to improve agricultural productivity while minimizing environmental impacts and enhancing resilience to climate change. CSA practices such as crop diversification, soil conservation, and water management can help mitigate the impacts of climate change on food safety by reducing the risk of contamination and enhancing the quality of agricultural products. Furthermore, policies aimed at promoting sustainable food production systems can contribute to mitigating food safety risks associated with climate change. These policies may include incentives for farmers to adopt sustainable farming practices, support for organic farming, and regulations to reduce the use of chemical inputs in agriculture. By promoting environmentally friendly farming practices, such policies can help minimize the occurrence of foodborne pathogens and chemical contaminants in food products, thereby enhancing food safety. In addition to promoting sustainable agricultural practices, policy strategies for managing food safety risks associated with climate change also focus on strengthening food safety systems and enhancing surveillance and monitoring mechanisms. This includes investing in infrastructure and capacity building to improve food safety testing and inspection capabilities, as well as enhancing early warning systems for foodborne disease outbreaks. By strengthening food safety systems, policymakers can better detect and respond to emerging food safety risks exacerbated by climate change, thereby reducing the likelihood of foodborne illness and protecting public health. Furthermore, international collaboration and knowledge sharing are essential components of effective policy strategies for managing food safety risks associated with climate change. Given the global nature of both climate change and the food supply chain, coordinated action at the international level is crucial for addressing shared challenges and exchanging best practices. International organizations such as the World Health Organization (WHO), the Food and Agriculture Organization (FAO), and the World Organization for Animal Health (OIE) play a critical role in facilitating collaboration and providing technical assistance to countries in developing and implementing effective food safety policies in the context of climate change. Managing food safety risks associated with climate change and agriculture requires a multifaceted approach that integrates climate adaptation, sustainable agriculture, and robust food safety systems. By implementing proactive policy strategies that promote sustainable practices, strengthen food safety systems, and foster international collaboration, policymakers can mitigate the impacts of climate change on food safety and ensure the availability of safe and nutritious food for all.

Role of the World Organisation for Animal Health in global wildlife disease surveillance.

This paper examines the role of the World Organisation for Animal Health (WOAH) in the global surveillance and management of pathogens. Since the creation of WOAH, one of its missions has been to ensure transparency of the global animal health situation. WOAH established a Working Group on Wildlife in 1994 to inform and advise WOAH Members, leadership, and technical teams on issues relating to wildlife health. In 2020 it conducted a consultation with its Members before developing a Wildlife Health Framework to improve global health and wildlife conservation. WOAH Members report diseases in wildlife, but detections are dependent on the surveillance systems in place. As an example of data collected in the most recent years (2019-2023), 154 countries have reported 68,862,973 cases, through alert messages and weekly updates, for 84 diseases. One-hundred and fifty countries have reported 68,672,115 cases in domestic animals and 95 countries have reported 190,858 cases in wild animals. These figures illustrate the performance of the organization in collecting data on wildlife, and provide an indication of the difference in completeness of data collected in domestic animals and wildlife. There are several challenges to wildlife disease surveillance and real figures remain unknown; they depend on the existence, quality and sensitivity of national surveillance. A WOAH-led One Health approach with cross-sectoral collaboration is needed to improve surveillance sensitivity, address the challenges and help safeguard wildlife population health and biodiversity conservation.

Current and potential use of animal disease data by stakeholders in the global south and north

What cannot be measured will not be managed. The Global Burden of Animal Diseases (GBADs) will generate information on animal disease burdens by species, production system, type and gender of farmer and consumer, geographical region, and time period. To understand the demand for burden of animal disease (BAD) data and how end-users might benefit from this, we reviewed the literature on animal diseases prioritisation processes (ADPP) and conducted a survey of BAD information users. The survey covered their current use of data and prioritizations as well as their needs for different, more, and better information. We identified representative (geography, sector, species) BAD experts from the authors’ networks and publicly available documents and e-mailed 1485 experts. Of 791 experts successfully contacted, 271 responded (34% response rate), and 185 complete and valid responses were obtained. Most respondents came from the public sector followed by academia/research, and most were affiliated to institutions in low- and middle-income countries (LMICs). Of the six ADPPs commonly featured in literature, only three were recognised by more than 40% of experts. An additional 23 ADPPs were used. Awareness of ADDPs varied significantly by respondents. Respondents ranked animal disease priorities. We used exploded logit to combine first, second and third disease priorities to better understand prioritzation and their determinants. Expert priorities differed significantly from priorities identified by the ADDPs, and also from the priorities stated veterinary services as reported in a survey for a World Organisation of Animal Health (WOAH) technical item. Respondents identified 15 different uses of BAD data. The most common use was presenting evidence (publications, official reports, followed by disease management, policy development and proposal writing). Few used disease data for prioritzation or resource allocation, fewer routinely used economic data for decision making, and less than half were aware of the use of decision support tools (DSTs). Nearly all respondents considered current BAD metrics inadequate, most considered animal health information insufficiently available and not evidence-based, and most expressed concerns that decision-making processes related to animal health lacked transparency and fairness. Cluster analysis suggested three clusters of BAD users and will inform DSTs to help them better meet their specific objectives. We conclude that there is a lack of satisfaction with current BAD information, and with existing ADDPs, contributing to sub-optimal decision making. Improved BAD data would have multiple uses by different stakeholders leading to better evidenced decisions and policies; moreover, clients will need support (including DSTs) to optimally use BAD information.

Advancing One Health through veterinary education: a mixed methods needs assessment for implementing a WOAH-harmonized national veterinary medicine curriculum in Ethiopia.

International organizations now actively promote and implement One Health collaborative approaches to prevent, detect, and control diseases in humans and animals, recognizing the critical importance of the veterinary and agricultural sectors. Moreover, Veterinary Services are chronically under-resourced, especially in low- and middle-income countries. Given the importance of National Veterinary Services to food security, nutrition, poverty alleviation, and global health security, strengthening veterinary capacity is a priority for the international community. The World Organisation for Animal Health (WOAH) outlines a set of minimum competencies veterinarians need to support National Veterinary Services effectively. To improve the quality of veterinary education, Ethiopia has developed a new 2020 national curriculum that is harmonized with the WOAH competencies. A mixed methods needs assessment was conducted to identify barriers and challenges that Ethiopian veterinary medicine programs have faced in implementing the new WOAH-harmonized national curriculum. Representatives from active veterinary programs granting a Doctor of Veterinary Medicine (DVM) degree were invited to share their experiences via an online survey and follow-up focus group discussion. Fourteen veterinary programs, representing 93% of eligible programs nationwide, participated in the needs assessment. Quantitative analysis indicated that the most difficult topics associated with the new curriculum included Organization of Veterinary Services (Competency 3.1), Inspection and Certification Procedures (3.2), and practical applications of the regulatory framework for disease prevention and control (multiple competencies). Challenges associated with specific instructional methodologies, particularly the facilitation of off-site (private and public sector) student training, were also perceived as barriers to implementation. Focus group discussions elucidated reasons for these challenges and included limitations in faculty expertise, resource constraints (e.g., supplies, infrastructure), and access to off-site facilities for hands-on teaching. The results of this needs assessment will be used to identify and prioritize solutions to implementation challenges, helping Ethiopian veterinary medicine programs move the new WOAH-harmonized curriculum from theory to practice. As veterinarians are integral partners in advancing One Health, strengthening the capacity of Veterinary Services can ultimately safeguard animal and human health, grow economies, and improve lives.

Exosomes secreted by CSFV-infected cells evade neutralizing antibody to activate innate immune responses and establish productive infection in recipient cells

Exosomes, which are small membrane-enclosed vesicles, are actively released into the extracellular space by a variety of cells. Growing evidence indicates that exosomes derived from virus-infected cells can selectively encapsulate viral proteins, genetic materials, or even entire virions. This enables them to mediate cell-to-cell communication and facilitate virus transmission. Classical swine fever (CSF) is a disease listed by the World Organisation for Animal Health (WOAH) Terrestrial Animal Health Code and must be reported to the organisation. It is caused by classical swine fever virus (CSFV) belonging to the Flaviviridae family. Recent studies have demonstrated that extracellular vesicles originating from autophagy can facilitate the antibody-resistant spread of classical swine fever virus. However, due to the extreme difficulty in achieving a complete separation from virions, the role of exosomes during CSFV infection and proliferation remains elusive. In this study, we ingeniously chose to perform immunoprecipitation (IP) targeting the CSFV E2 protein, thereby achieving the complete removal of infectious virions. Subsequently, we discovered that the purified exosomes are shown to contain viral genomic RNA and partial viral proteins. Furthermore, exosomes secreted by CSFV-infected cells can evade CSFV-specific neutralizing antibodies, establish subsequent infection, and stimulate innate immune system after uptake by recipient cells. In summary, exosomes play a critical role in CSFV transmission. This is of great significance for in-depth exploration of the characteristics of CSFV and its complex interactions with the host.

A many-objective optimization approach for weight gain and animal welfare in rotational grazing of cattle

The “multidimensional” nature of the concept of welfare is reflected in the definition proposed by the World Organization for Animal Health (OIE), according to which an animal is in a satisfactory state of welfare when it is healthy, comfortable, and well-fed, can express its innate behavior, and does not suffer pain, fear, or distress. Many of these aspects, in the real context of a cattle farm, are not considered, and most of the farmers’ decisions are based on their experiences. In this proposal, we establish a many-objective optimization model for rotational grazing allocation based on six objectives that consider cattle weight gain and travel, as well as their welfare. The model is solved using the NSGA-III algorithm, and its performance is evaluated using a simulation study of 90 days of rotational grazing in which it is compared with the traditional grazing strategy. Average weight gains of up to 36.7 kg per animal are achieved at the end of the three months of simulated grazing using the proposed model. The results indicate that the allocation model generates an average weight gain that is statistically greater than that generated by the traditional rotation method but also guarantees improved animal welfare, the main contribution of our approach.

Simultaneous Detection of Antigen and Antibodies of African Swine Fever in a Novel Combo Lateral Flow Assay.

African swine fever (ASF) is a contagious disease of wild boar and domestic pigs notifiable to the World Organisation for Animal Health due to its high socio-economic impact. ASF is caused by the complex ASF virus (ASFV), and it can present different clinical manifestations that can be confused with other diseases; for this reason, laboratory testing is necessary for the proper diagnosis of clinically suspected animals. Despite the efforts put into it over decades, no treatment or safe vaccine is globally available, and disease control is based on early diagnosis and the implementation of strict biosecurity measures. In this context, rapid tests have the potential to accelerate and facilitate the identification of infected animals by giving fast on-site results. In this work, we improved the available point-of-care assays for the diagnosis of the disease by the development of a more specific antigen test and a more sensitive antibody test. This antibody detection test allowed for the earlier detection of infected animals than two commercial indirect ELISAs (statistically significant). Moreover, we developed a combined dual rapid test, unifying, in the same cassette, an antigen detection strip and an antibody detection strip. In this study, we confirmed that this combo approach is a useful tool for implementing rapid tests in the field since it increases the percentage of positive samples detected, even when PCR turns negative, while maintaining a good specificity.

Sandfish (Holothuria scabra) as potential reservoir of white spot syndrome virus (WSSV) when co-cultured with black tiger prawn (Penaeus monodon)

Since the first occurrence of White Spot Disease (WSD) in 1992, it is still listed as one of the crustacean diseases by the World Organisation for Animal Health in 2022. Horizontal transmission in co-culture systems is one of the usual modes in the spread of the disease. WSD outbreak was recorded during the experimental run of the co-culture of black tiger prawn (Penaeus monodon) and sandfish (Holothuria scabra) in the grow-out phase. In this study, artificial infection through two cohabitation experiments were conducted to determine if H. scabra is a potential non-crustacean vector or reservoir of WSSV. Samples were checked using one-step and nested PCR for increased readout sensitivity of virus infection to investigate the horizontal transmission between prawn and sandfish. During the first cohabitation (5 days) where WSSV (+) prawn were cohabited with WSSV (-) sandfish, 100% of the prawn were one-step PCR positive for WSSV while 100% of the sandfish were nested PCR positive. Subsequently, WSSV (+) sandfish from the first cohabitation were transferred to another tank to be cohabited with WSSV (-) prawn. Sampling of both prawn and sandfish was done every 6 days post-infection (dpi). At 6 to 18 dpi, prawn and sandfish were nested PCR positive. At 25 dpi, there were no prawns left due to mortality and 1 of the 3 remaining sandfish was nested PCR positive. Based on the results, it elucidates the ability of sandfish to bioaccumulate the viral particles when cohabited with WSSV (+) prawn. Results suggest that WSSV is viable in the sandfish confirming its potential as a vector or reservoir due to the consistent nested PCR positive results of the prawn during the second cohabitation. Hence, it can be inferred that sandfish can be a potential non-crustacean vector or reservoir of WSSV for a limited period of time.

Development and evaluation of a time-resolved fluorescence labelled immunochromatographic strip assay for rapid and quantitative detection of bovine herpesvirus 1.

Bovine herpes virus 1 (BoHV-1) causes a wide variety of diseases in wild and domestic cattle. The most widely used method for viral identification is real-time PCR, which can only be performed in laboratories using sophisticated instruments by expert personnel. Herein, we developed an ultrasensitive time-resolved fluorescence lateral flow immunochromatographic strip (ICS) assay for detecting BoHV-1 in bovine samples using a monoclonal antibody against BoHV-1 labelled with fluorescent microspheres, which can be applied in any setting. The intact process from sample collection to final result can be achieved in 15 min. The limit of detection of the assay for BoHV-1 was 102 TCID50/100 μL. The coincidence rate of the ICS method and real-time PCR recommended by the World Organization for Animal Health (WOAH) was 100% for negative, 92.30% for positive, and 95.42% for total, as evaluated by the detection of 131 clinical samples. This detection method was specifically targeted to BoHV-1, not exhibiting cross-reactivity with other bovine pathogens including BoHV-5. We developed an ICS assay equipped with a portable instrument that offers a sensitive and specific platform for the rapid and reliable detection of BoHV-1 in the field. The Point-of-Care test of BoHV-1 is suitable for the screening and surveillance of BoHV-1 in dairy herds.

Epidemiological Analyses of the First Incursion of the Epizootic Hemorrhagic Disease Virus Serotype 8 in Tunisia, 2021-2022.

Epizootic hemorrhagic disease (EHD) is a non-contagious arthropod-transmitted viral disease and a World Organization for Animal Health (WOAH)-listed disease of domestic and wild ruminants since 2008. EHDV is transmitted among susceptible animals by a few species of midges of genus Culicoides. During the fall of 2021, a large outbreak caused by the epizootic hemorrhagic disease virus (EHDV), identified as serotype 8, was reported in Tunisian dairy and beef farms with Bluetongue virus (BTV)-like clinical signs. The disease was detected later in the south of Italy, in Spain, in Portugal and, more recently, in France, where it caused severe infections in cattle. This was the first evidence of EHDV-8 circulation outside Australia since 1982. In this study, we analyzed the epidemiological situation of the 2021-2022 EHDV outbreaks reported in Tunisia, providing a detailed description of the spatiotemporal evolution of the disease. We attempted to identify the eco-climatic factors associated with infected areas using generalized linear models (GLMs). Our results demonstrated that environmental factors mostly associated with the presence of C. imicola, such as digital elevation model (DEM), slope, normalized difference vegetation index (NDVI), and night-time land surface temperature (NLST)) were by far the most explanatory variables for EHD repartition cases in Tunisia that may have consequences in neighboring countries, both in Africa and Europe through the spread of infected vectors. The risk maps elaborated could be useful for disease control and prevention strategies.