For the first time we built a correlative model for predicting the distribution of H. marginatum, one of the main vector of Crimean-Congo Haemorrhagic fever virus (CCHFV), at high resolution in a recently colonized area, namely south of France. Field tick collections were conducted on horses from 2016 to 2021 in 14 French southern departments, which resulted in a first map of H. marginatum on the national territory. Such updated presence/absence data, as well as the mean number of H. marginatum per examined animal (mean parasitic load) as a proxy of the tick abundance, were correlated to multiple parameters that described the climate and habitats characterizing each collection site, as well as movements of horses as a possible source of tick diffusion and new establishment. Our model highlighted the importance of warm temperatures all along the year, as well as dry conditions during summer and moderate annual humidity for the establishment of H. marginatum. A predominance of open natural habitats in the environment was also identified as a supporting factor, in opposition to artificial and humid habitats that were determined as unsuitable. Based on this model, we predicted the current suitable areas for the establishment of the tick H. marginatum in South of France, with a relatively good accuracy using internal and external validation methods. Concerning tick abundance, some correlative relationships were similar than in the occurrence model but the type of horse movements were also pointed out as an important factor explaining the mean parasitic load, leading to differential exposure to ticks. The limitations of estimating and modelling H. marginatum abundance in a correlative model are discussed.
During the European emergence of Schmallenberg virus (SBV) in 2011, examination of Culicoides spp. showed that SBV infected midges were present across Denmark. However, SBV associated malformations in ruminant species have not been reported in Denmark. In April 2021, seven calves with severe congenital generalized arthrogryposis and reduced body weight originating from a narrow region of the Jutlandic peninsula were submitted for examination. Analysis of fetal brain tissue for SBV viral RNA and pleural effusion for fetal anti-SBV antibodies identified SBV as the cause of the congenital syndrome. Backwards calculation from the calving dates indicated the occurrence of an unnoticed emergence of SBV in Denmark from early August 2020 and during the late summer and autumn. As SBV associated malformations may lead to dystocia urging for fetotomy or Cesarean section, veterinarians performing obstetric intervention are first line personnel in recognition of SBV emergence in domestic ruminants.
Since African swine fever (ASF) was first reported in 1921, it has brought huge economic losses to the world pig industry. No vaccine or therapy is available. Rapid and effective diagnostics are key steps in managing ASF. We generated three monoclonal antibodies (mAbs) against the African swine fever virus (ASFV) phosphoprotein p30 and designated these as 7D2, 8C8 and 2F6. Epitope mapping revealed that mAb 7D2 recognized 26VFHAG SLYNW 35 of p30, and mAb 8C8 and 2F6 recognized 1MDFIL NISMK MEVIF KTDLR 20 of p30. Furthermore, epitope 1MDFIL NISMK MEVIF KTDLR 20 and 26VFHAG SLYNW 35 could be well recognized by ASFV-positive sera from natural infected pigs, suggesting that they were natural linear B-cell epitope. Conservation analysis indicated that epitope 1MDFIL NISMK MEVIF KTDLR 20 and 26VFHAG SLYNW 35 were highly conserved among the different strains of ASFV. This is the first research to characterize specific mAbs against p30 protein. These findings may facilitate further understanding the function of p30 protein and development of diagnostic tools.
Cichlids include several fish species having a high economic value in the field of aquaculture. The ornamental fish export trade is mostly based on fish from the african Lake Malawi. Despite their huge economic importance, management of ornamental fisheries is challenged by a paucity of information on the status of the exploited fish stock. The possibility of guaranteeing healthy animals is of paramount importance and has several implications, both for commercial and sanitary reasons. Grossly, cutaneous nodules and black spots are pathological findings frequently encountered in fish, suggesting a meandering disease without a specific etiologic association. Ornamental fish species are plagued by mycobacteriosis, which is quite classically associated with granulomas. This work focuses on debilitated ornamental cichlids presenting cutaneous nodules and black spots and sampled during routinary managing activities held in an aquarium commercial facility; the fish underwent pathological analysis and the presence of pathogens was investigated through a molecular approach. In particular, the presence of lymphocystis disease virus (LCDV), typically associated with cutaneous nodular disease, was excluded.Histologically the granulomas were localized in the spleen, sometimes extending to the other visceral organs. Bacterial Heat-Shock Protein 65 PCR products were detected in tissues associated to granulomas and molecular investigation identified Mycobacterium spp. in two samples and Cutibacterium acnes in seven samples. Variably sized round “Hamazaki-Wesenberg-like” bodies were immunolabeled with C. acnes antibody within macrophages forming the granuloma in the spleen. C. acnes has been recently detected by Next Generation Sequencing in the microbiome of internal organs of fish. The role of C. acnes within internal fish tissues deserves attention; its role as potential granulomatogenous agent, is taken in consideration.
CDC estimates 1 million dogs are imported into the United States annually. With the movement of large numbers of animals into the United States the risk of disease importation is a concern, especially for emerging diseases. Dogs that arrive to the United States ill or dead are investigated by public health authorities to ensure dogs are not infected with diseases of concern (such as rabies). We identified factors associated with illness and death in imported dogs and estimated the initial investigation cost to public health authorities. Dog importation data from the CDC’s Quarantine Activity Reporting System were reviewed from 2010–2018. The date of entry, country of origin, port of entry, transportation method, and breed were extracted to examine factors associated with illness and death in dogs during international travel. Costs for public health investigations were estimated from data collected by the Bureau of Labor Statistics and Office of Personal Management. Death or illness was more likely to occur in brachycephalic breeds (aOR=3.88, 95%CI 2.74–5.51). Transportation of dogs via cargo (aOR=2.41, 95%CI 1.57–3.70) or as checked baggage (aOR=5.74, 95%CI 3.65–9.03) were also associated with death or illness. On average, 19 dog illnesses or deaths were reported annually from 2010–2018. The estimated annual cost to public health authorities to conduct initial public health assessments ranged from $2,071–$104,648. Current regulations do not provide adequate resources or mechanisms to monitor the rates of morbidity and mortality of imported dogs. There are growing attempts to assess animal welfare and communicable disease importation risks; however, responsibility for dogs’ health and well-being is overseen by multiple agencies. A joint federal agency approach to identify interventions that reduce dog morbidity and mortality during flights while continuing to protect U.S. borders from public health and foreign animal disease threats could be beneficial.
Lumpy skin disease (LSD) is an emerging pox viral disease affecting cattle population worldwide. In India, the first outbreak of LSD is reported during August 2019 in Odisha state, which then followed by outbreaks in crossbred and indigenous cattle population of other states. Present investigation designed to study the prevalence, pathomorphological changes and molecular detection of LSD virus in naturally infected cattle. The overall morbidity of LSD was 4.48% among 30 dairy farms. Skin nodular biopsy, whole blood and serum samples (n= 66) were collected for the diagnosis of LSD by histopathology, PCR and sequencing. The envelope protein gene (P32), Fusion protein (F) and DNA dependent RNA polymerase 30 kDa subunit (RPO30) genes were targeted for PCR testing. Out of 66, 46 cattle showed generalized skin nodules and papules of various sizes (0.5 - 6.5cm) on the skin particularly at neck, face, nose, tail, perineum and udder. Microscopic examination of the skin nodule biopsy tissue revealed presence of diffuse granulomatous inflammation, hyperkeratosis, focal to diffuse vasculitis and lymphangitis, vacuolar degeneration, spongiosis and acanthosis. The inflammatory cells typically comprised of macrophages, lymphocytes, neutrophils and eosinophils along with diffuse necrosis in dermis in chronic cases. The eosinophilic intracytoplasmic viral inclusions in keratinocytes and epithelial cells were detected in few cases. Gel-PCR assay detected P32 gene in 83%, F gene in 72% and RPO30 gene in 77% of skin biopsy samples. Three blood samples were also found positive for P32 gene by PCR. Whereas TaqMan™ probe Real Time PCR targeting EEV glycoprotein gene (LSDV126) detected LSDV in 94% of biopsy samples and three blood samples which indicated its higher sensitive for the diagnosis of LSDV. Phylogenetic analysis of RPO30 gene sequence showed that the isolates from this study were grouped in same cluster with LSDV isolates of Bangladesh, Kenya and other Indian isolates detected during 2019-20.
During the first pandemic wave, the dark figure of SARS-CoV-2 exposure was estimated to be high, however, an accelerated loss of antibodies was reported after about 6 months post infection. This study was performed to unveil the group of serological non-responders (NR) in PCR+ individuals 6-9 months after the first pandemic SARS-CoV-2 wave in spring 2020 and to evaluate their specific cellular immune response towards spike-molecule compared to PCR- and not PCR-tested (NT) household contact persons. SARS-CoV-2-specific antibodies were quantified using a commercial ELISA kit. The synergistic binding strength was assessed as relative avidity index (RAI) using ammonium-thiocyanate as chaotropic agent. The specific IFNγ-production in response to spike-protein was determined in spot-forming-units (SFU) by ELISPOT-assay. In PCR- 50.0%, in PCR+ 35.3% and in NT 20.7% had undetectable IgG-anti-SARS-CoV-2 and were considered non-responders (NR). All seropositive responders from the PCR-, 45.5% of PCR+ and 43.0% of NT developed high avidity (RAI>60%). In serological responders, cellular responses were detected in 75.0% PCR-, 75.8% PCR+ and 66.7% NT. In serological NR, positive SFU were found in 75.0% PCR-, 22.2% PCR+ and 17.4% NT. Significantly higher stimulation-indices were seen in PCR+ responders compared to PCR+ serological NR. Our findings showed that also PCR- and household contact persons who were not tested (NT) developed SARS-CoV-2-specific humoral and cellular immune responses. The relatively large proportion of serological non-responders but also the proportion of cellular non-responders within the group of IgG-positive individuals after PCR+ infection underlines the need for COVID-19 vaccinations in the reconvalescent group.
From 2003 onwards, three pandemics have been caused by coronaviruses: severe acute respiratory syndrome coronavirus (SARS-CoV); middle east respiratory syndrome coronavirus (MERS-CoV); and, most recently, SARS-CoV-2. Notably, all three were transmitted from animals to humans. This would suggest that animals are potential sources of epidemics for humans. The emerging porcine delta-coronavirus was reported to infect children. This is a red flag that marks the ability of PDCoV to break barriers of cross-species transmission to humans. Therefore, we conducted molecular genetic analysis of global clade PDCoV to characterize spatio-temporal patterns of viral diffusion and genetic diversity. PDCoV was classified into three major lineages, according to distribution and phylogenetic analysis of PDCoV. It can be determined that PDCoV originated in Asia—most likely in Southeast Asia—through inference of migration rate and transmission routes. We also selected six special spike amino acid sequences to align and analyze to find seven significant mutation sites. The accumulation of these mutations may enhance dynamic movements, accelerating spike protein membrane fusion events and transmission. Altogether, our study offers a novel insight into the diversification, evolution, and interspecies transmission and origin of PDCoV and emphasizes the need to study the zoonotic potential of the PDCoV and comprehensive surveillance and enhanced biosecurity precautions for PDCoV.
The emergence of drug-resistant tuberculosis (DR-TB) is becoming a challenge to the national TB control programs including Ethiopia. Different risk factors are associated with the emergence of DR-TB. Identifying these risk factors in a local setting is important to strengthen the effort to prevent and control DR-TB. Thus, this study aimed to assess the risk factors associated with drug-resistant TB in Ethiopia. The Preferred Reporting Items for Systematic Reviews and Meta-analysis checklist was followed to conduct this study. We systematically searched the articles from electronic databases and gray literature sources. We used the Joanna Briggs Institute Critical Appraisal tools to assess the quality of studies. Data were analyzed using STATA version 15. We estimated the pooled OR along with 95%CI for each risk factor. The heterogeneity of the studies was assessed using the forest plot and I 2 heterogeneity test. Besides, we explored the presence of publication bias through visual inspection of the funnel plot and Egger’s regression test. After intense searching, we found 2238 articles, and 27 eligible studies were included in the final analysis. Based on the pooled analysis of the odds ratio, unemployment (OR; 2.71, 95% CI; 1.64, 3.78), having a history of the previous TB (OR; 4.83, 95% CI; 3.02, 6.64), having contact with a known TB patient (OR; 1.72, 95% CI; 1.05, 2.40), having contact with a known MDR-TB patient (OR; 2.54, 95% CI; 1.46, 3.63), and having pulmonary TB (OR; 1.80, 95% CI; 1.14, 2.45) were found to be the risk factors of drug-resistant TB. While older age TB patients (OR; 0.77, 95% CI; 0.60, 0.95) including age above 45 years OR; (0.76, 95% CI; 0.55, 0.97), and males (OR; 0.86, 95% CI; 0.76, 0.97) were found to had lower risk of DR-TB compared to their counterparts. A previous history of TB treatment is a major risk factor for acquiring DR-TB in Ethiopia that might be due to poor adherence during the first-line anti TB treatment. Besides, having contact with a known TB patient, having contact with a known MDR-TB patient, having pulmonary TB, and being unemployed were the risk factors of DR-TB in Ethiopia. Thus, active screening of TB contacts for DR-TB might help to detect DR-TB cases as early as possible and could help to mitigate its further transmission across the community.
Rift Valley fever virus (RVFV) is a mosquito-borne pathogen with significant human and veterinary health consequences that periodically emerges in epizootics. RVF causes fetal loss and death in ruminants and in humans can lead to liver and renal disease, delayed-onset encephalitis, retinitis, and in some cases severe hemorrhagic fever. A live attenuated vaccine candidate (DDVax), was developed by the deletion of the virulence factors NSs and NSm from a clinical isolate, ZH501, and has proven safe and immunogenic in rodents, pregnant sheep and non-human primates. Deletion of NSm also severely restricted mosquito midgut infection and inhibited vector-borne transmission. To demonstrate environmental safety, this study investigated the replication, dissemination and transmission efficiency of DDVax in mosquitoes following oral exposure compared to RVFV strains MP-12 and ZH501. Infection and dissemination profiles were also measured in mosquitoes 7 days after feeding on goats inoculated with DDvax or MP-12. Hypothesis: DDVax should infect mosquitoes at significantly lower rates than other RVF strains and, due to lack of NSm, be transmission incompetent. Exposure of Ae. aegypti and Cx. tarsalis to 6-8 log 10 plaque forming units (PFU)/mL DDVax by artificial bloodmeal resulted in significantly reduced DDVax infection rates in mosquito bodies compared to controls. Plaque assays indicated negligible transmission of infectious DDVax in Cx. tarsalis saliva (1/140 sampled) and none in Ae aegypti saliva (0/120). Serum from goats inoculated with DDVax or MP-12 did not harbor detectable infectious virus by plaque assay at 1, 2, or 3 days-post-inoculation; infectious virus was, however, recovered from mosquito bodies that fed on goats vaccinated with MP-12 (13.8% and 4.6%, respectively), but strikingly, DDvax positive mosquito bodies were greatly reduced (4%, and 0%, respectively). Furthermore, DDVax did not disseminate to legs/wings in any of the goat-fed mosquitoes. Collectively, these results are consistent with a beneficial environmental safety profile .
Foot-and-mouth disease (FMD) is widely distributed in Sudan where outbreaks occur on an annual basis especially during the winter months (December-February). This study aimed to increase our understanding of the epidemiological patterns of FMD in Sudan and connections to neighbouring countries by characterising the genetic sequences of FMD viruses (FMDV) collected from seven Sudanese states over a 10-year period (between 2009 and 2018). FMDV was detected in 91 of the 265 samples using an antigen-detection ELISA. Three serotypes were detected: O (46.2%), A (34.1%), and SAT 2 (19.8%). Fifty-three of these samples were submitted for sequence analyses, generating sequences that were characterised as belonging to O/EA-3 (n=18), A/AFRICA/G-IV (n=23) and SAT 2/VII/Alx-12 (n=12) viral lineages. Phylogenetic analyses provided evidence that FMDV lineages were maintained within Sudan, and also highlighted epidemiological connections to FMD outbreaks reported in neighbouring countries in East and North Africa (such as Ethiopia and Egypt). This study motivates continued FMD surveillance in Sudan to monitor the circulating viral lineages and broader initiatives to improve our understanding of the epidemiological risks in the region.
The importance of social and spatial structuring of wildlife populations for disease spread, though widely recognized, is still poorly understood in many host-pathogen systems. In particular, system specific kin relationships among hosts can create contact heterogeneities and differential disease transmission rates. Here, we investigate how distance-dependent infection risk is influenced by genetic relatedness in a novel wild boar ( Sus scrofa) - African swine fever (ASF) system. We hypothesized that the infection risk would correlate positively with proximity and relatedness to ASF-infected individuals but expected those relationships to weaken with distance between individuals due to decay in contact rates and genetic similarity. ASF infection risk was shaped by the number of infected animals throughout the zone of potential contact (0-10 km) but not beyond it. This effect was the strongest at close distances (0-2 km) and weakened further on (2-10 km), consistent with decreasing probability of contact. Overall, there was a positive association between genetic relatedness to infectees and infection risk within the contact zone but this effect varied in space. In the high-contact zone (0-2 km), infection risk was not influenced by relatedness when controlled for the number of ASF-positive animals. However, infections were more frequent among close relatives indicating that familial relationships could have played a role in ASF transmission. In the medium-contact zone (2-5 km), infection risk and frequency of paired infections were associated with relatedness. Relatedness did not predict infection risk in low- and no-contact zones (5-10 and >10 km, respectively). Together, our results indicate that the number of nearby infected individuals overrides the effect of relatedness in shaping ASF transmission rates which nevertheless can be higher among close relatives. Highly localized transmission highlights the possibility to control the disease if containment measures are employed quickly and efficiently.
Mongolia and Eastern Siberia, Russia are border regions in Asia with high incidence of tuberculosis (TB). In this study, we aimed to investigate MDR -TB transborder transmission with a focus on endemic and epidemic Mycobacterium tuberculosis clones and drug resistance patterns. M. tuberculosis strains (291 from Mongolia and 754 from Russia) were collected within cross-sectional population-based surveys in 2010-2016. DNA was genotyped in 24 MIRU-VNTR loci and by PCR testing of the key SNP markers to discriminate within Beijing genotype. In total, 1045 isolates were divided into 435 MIRU-types that were assigned to Lineage 2 (Beijing isolates) and Lineage 4 (Ural, Haarlem, Latin-American-Mediterranean [LAM], S, and unclassified isolates). Beijing genotype was dominant in both countries, but most of Russian and all Mongolian Beijing strains belonged to different subtypes of the modern Beijing sublineage with only negligible overlap between the two countries. In particular, the Beijing types #342-32, #3819-32, #1773-32 (Asian African 2 group) were found only in Mongolia. LAM was the most common non-Beijing genotype (11.0% in Mongolia and 14.7% in Russia) and its isolates mostly belonged to LAM-RUS branch. MDR rate was higher in Russia compared to Mongolia among newly diagnosed patients: 29.4% versus 4.2% (p < 0.001) but similar and high in the retreatment subgroups (65.8% and 67.4%, respectively). In Russian collection, a higher MDR rate was observed in (i) Beijing compared to non-Beijing (47.5% versus 38.8%, p = 0.03), (ii) Beijing B0/W148 subtype compared to Beijing Central Asian/Russian subtype (64.5% versus 39.3%, p <0.001). In Mongolia, MDR rate was similar in Beijing (29.7%) and non-Beijing (27.5%) genotypes. In conclusion, population structures of the Beijing genotype in Mongolia and Russian borderline regions differ significantly including specific patterns of drug resistance. In contrast, largely overlapping LAM subtypes may correlate with historical endemic circulation of the LAM-RUS branch in Northern Eurasia.
Introduction: The Coronavirus Disease 2019 (COVID-19) pandemic has had a variable worldwide impact, likely related to country-level characteristics. In this ecological study, we explored the association of COVID-19 case rates (per 100,000 people) and death rates (per 100,000 people) with country-level population health characteristics, economic and human development indicators, and habitat-related variables. Methods: To calculate country-level COVID-19 case and death rates, the number of cases and deaths were extracted from the Johns Hopkins Coronavirus Resource Center for 2020. Country-level population health characteristics, economic and human development indicators, and habitat-related variables were extracted from several publicly available online sources of international organizations. Results were tabulated according to world zones and country economies. Univariate and multivariable linear regression analyses were performed to examine determinants of COVID-19 case rates and death rates. Results: A total of 187 countries and territories were analyzed, with an aggregate COVID-19 case rate of 779 per 100,000 people, a death rate of 19 per 100,000 people, and a case-fatality rate of 2.4%. For country-level population health characteristics, a higher percentage rate of adults with obesity and a higher percentage rate of adults with high blood pressure was independently associated with a higher COVID-19 case rate, and a higher percentage rate of adults with obesity was associated with a higher COVID-19 death rate. For country-level economic and human development indicators, only a higher gross domestic product percentage rate spent on total health expenditure and a higher human development index was independently associated with a higher COVID-19 case rate and death rate. A higher percentage of urban population was independently associated with a higher COVID-19 death rate, whereas a higher income per capita was independently associated with a lower COVID-19 death rate. For country-level habitat-related variables, a higher average household size and a higher percentage rate of population with primary reliance on polluting fuels and technologies was independently associated with a lower COVID-19 case rate and death rate whereas a higher percentage rate of households with at least one-member age 65 years or over was associated with a higher case rate and death rates. Conclusion: This ecological study informs the need to develop country-specific public health interventions to better target populations at high risk for COVID-19, and test environmental interventions to prevent indoor transmission of SARS-CoV-2, taking into consideration population health characteristics, economic and human development indicators, and habitat-related variables that are unique to each country.
Foot-and-mouth disease (FMD) is endemic in India, where circulation of serotypes O, A and Asia 1 is frequent. In the past two decades, many of the most widespread and significant FMD lineages globally have emerged from the South Asia region. Here, we provide an epidemiological assessment of the ongoing mass vaccination programs in regard to post-vaccination monitoring and outbreak occurrence. The objective of this study was to quantify the spatiotemporal dynamics of FMD outbreaks and to assess the impact of the mass vaccination program between 2008 to 2016 with available antibody titer data from the vaccination monitoring program, alongside other risk factors that facilitate FMD spread in the country. We first conducted a descriptive analysis of epidemiological outcomes of governmental vaccination programs in India, focusing on antibody titer data from >1 million animals sampled as part of pre- and post-vaccination monitoring and estimates of standardized incidence ratios calculated from reported outbreaks per state/administrative unit. The percent of animals with inferred immunological protection (based on ELISA) was highly variable across states, but there was a general increase in the overall percent of animals with inferred protection through time. In addition, the number of outbreaks in a state was negatively correlated with the percent of animals with inferred protection. Because standardized incidence ratios of outbreaks were heterogeneously distributed over the course of eight years, we analyzed the distribution of reported FMD outbreaks using a Bayesian space-time model to map high-risk areas. This model demonstrated a ~50% reduction in the relative risk of outbreaks in states that were part of the vaccination program. In addition, states that did not have an international border experienced reduced risk of FMD outbreaks. These findings help inform risk-based control strategies for India as the country progresses towards reducing reported clinical disease.
Host immune response as well as virulence factors are key in disease susceptibility. There are no known association studies of HLA class I and II alleles with chikungunya (CHIKV) infection in Latin American population. We aim to identify Human Leukocyte Antigen (HLA) alleles present in patients with CHIKV infection when compared to healthy controls, as well as allele association with the clinical spectrum of the disease. A cross-sectional analysis nested in a community cohort was carried out. We included patients 18 years and older with serological confirmation of CHIKV infection. HLA typing of HLA-A, HLA-B and HLA-DRB1 alleles was performed. Two-by-two tables were used to establish associations between allele presence and clinical characteristics. Data from 65 patients with confirmed CHIKV infection were analyzed for HLA typing. CHIKV infection was associated with the presence of HLA-A*68, HLA-B*35, HLA-DRB*01, HLA-DRB1*04 and HLA-DRB1*13 alleles with statistical significance when compared to healthy subjects. A statistically significant relationship was found between the presence of rash in the face or the abdomen and the presence of HLA-DRB1*04. Our study demonstrated that in our cohort, HLA type I as well as type II alleles are associated with CHIKV infection, and specifically an HLA type II allele with dermatological symptoms. Further research is needed to set a path for future investigation on genes outside the HLA system to improve knowledge in the pathophysiology of CHIKV infection and its host-pathogen interaction.
RT-PCR is currently the standard diagnostic method to detect symptomatic and asymptomatic individuals infected with SARS-CoV-2. However, RT-PCR results are not immediate and may falsely be negative before an infected individual sheds viral particle in the upper airway where swabs are collected. Infected individuals emit volatile organic compounds (VOCs) in their breath and sweat that are detectable by trained dogs. Here we evaluate the diagnostic accuracy of dog detection against SARS-CoV-2 infection. Fifteen dogs previously trained at two centres in Australia were presented to axillary sweat specimens collected from known SARS-CoV-2 human cases and non-cases. The true infection status of the cases and non-cases were confirmed based on RT-PCR results as well as clinical presentation. Across dogs, the overall diagnostic sensitivity (DSe) was 95.6% (95%CI: 93.6%-97.6%) and diagnostic specificity (DSp) was 98.1% (95%CI: 96.3%-100.0%). The DSp decreased significantly with non-case specimens sourced from UAE ( P-value < 0.001). The location of evaluation did not impact the detection performances. The accuracy of detection varied across dogs and experienced dogs revealed a marginally better DSp ( P-value = 0.003). The potential and limitations of this alternative detection tool are discussed.
Livestock industry supports the livelihood of around 1.3 billion people in the world, with swine industry contributing with 30 % of total livestock production worldwide. To maintain and guarantee this production, a pivotal point according to the OIE is addressing potential biohazards. To control them, permanent sero-surveillance is crucial to achieve more focused veterinary public health intervention and prevention strategies, to break the chains of transmission, and to enable fast responses against outbreaks. Within this context, multiplex assays are powerful tools with the potential to simplify surveillance programs, since they reduce time, labour, and variability within analysis. In the present work, we developed a multiplex bead-based assay for the detection of specific antibodies to six relevant pathogens affecting swine: ASFV, CSFV, PRRSV, SIV, TB, and HEV. The most immunogenic target antigen of each pathogen was selected as the target protein to coat different microsphere regions in order to develop this multiplex assay. A total of 1544 serum samples from experimental infections as well as field samples were included in the analysis. The 6plex assay exhibited credible diagnostic parameters with sensitivities ranging from 87.0 % to 97.5 % and specificities ranging from 87.9 % to 100.0 %, demonstrating it to be a potential high throughput tool for surveillance of infectious diseases in swine.