Transboundary and Emerging Diseases

Syndromic surveillance (SyS) is an important tool for early warning and monitoring of health in human and animal populations, but its use in aquaculture has been limited. Our study objective was to design a SyS system for Atlantic salmon aquaculture and to evaluate its performance in detecting pancreas disease (PD) outbreaks caused by salmonid alphaviruses on farms. We defined SyS outbreak alarms as cases where monthly farm mortality exceeded predefined cutoffs or deviated significantly from expected values based on predictive generalized linear models. These models were trained for each salmon production area in Norway, using data from 2014 to 2017. The outcome variable was fish mortality per farm-month, and input variables were production and environmental predictors, as well as an offset for the number of fish at risk. We also added autoregressive components to explain temporal dependency within fish cohorts. Subsequently, data from 2018 to 2021 was used to parameterize and validate the SyS system’s performance against the current national PD surveillance program, which relies on routine farm-screening tests using molecular techniques and reports of clinical findings. The study covered 19,119 farm-months, involving 1,618 fish cohorts. The performance of our SyS system varied across production areas, with sensitivity ranging from 80.5% to 87.4% and a false alarm rate of 45.3%–53.2%. The absence of alarms was usually observed in farms that were truly negative for PD, i.e., a negative predictive value range of 81.2%–94.0%. The median time for alarms being raised was either in the same month as the current PD surveillance program or 1 month prior or after it. Our results indicate that the SyS system is a valuable tool for monitoring mortality on salmon farms, but alarms are unspecific if evaluated against an individual disease (PD). Increasing the frequency and granularity of mortality reporting might improve the SyS system’s performance.

Equine infectious anaemia (EIA) is a life-long viral infection affecting equids, transmitted mechanically by biting flies and iatrogenic means. Despite its global distribution, active surveillance is limited, with passive clinical surveillance or control of specific equine sectors prevailing. In Italy, a national surveillance plan in horse, donkey, and mule populations has been established and includes mandatory passive and active surveillance through annual serological tests. During 2007–2010, the agar gel immunodiffusion (AGID) test served as both screening and confirmatory tests. Since 2011, a three-tier diagnostic pathway was introduced, utilizing the ELISA test for screening, AGID as the confirmatory test, and the immunoblot test for cases where ELISA was positive and AGID was negative. From a total equid population of 406,000 animals, 1,337,899 samples were analysed during 2007–2012, with 2,348 (0.18%) testing positive. EIA seroprevalence significantly decreased across all the species/hybrids during the study period. EIA occurrence was higher in mules (IRR = 48.90) and lower in donkeys (IRR = 0.56) compared to horses. The holding seroprevalence was 1.15%. Spatial analysis revealed clusters of infection in central Italy. These findings demonstrate that active systematic surveillance effectively reduces EIA prevalence in equid populations. Mules and working horses in wooded areas appeared to be at higher risk of infection and act as EIA reservoirs. Surveillance and control should be maintained and strengthened in these species/hybrids and in these areas to effectively control EIA. Passive surveillance alone is insufficient to eradicate the disease, and EIA remains a constant threat for the equine industry if active control is not implemented.

In recent years, significant changes have been observed in the distribution and abundance of local Dermacentor reticulatus populations. However, changes in D. reticulatus dynamics have not been studied in southeastern Poland. Our objective was to enhance our understanding of the environmental factors influencing the occurrence and density of D. reticulatus in this area. Additionally, we sought to investigate the genetic diversity of the tick population and the prevalence of tick-borne pathogens (TBPs). To this end, we established 45 study sites in the Subcarpathian province. Ticks were collected during their peak activity in both spring and autumn. A subset of randomly selected specimens underwent molecular analysis for TBPs screening, using high-throughput microfluidic real-time PCR. Positive amplicons were then sequenced, and phylogenetic analyses were conducted. Our findings confirmed the presence of D. reticulatus ticks in 24 surveyed sites, primarily concentrated in the northern and eastern parts of the region. The mean density of D. reticulatus ticks in their compact range was 5.8 ± 6.4 specimens/100 m². Notably, air temperature and altitude emerged as significant factors influencing the species’ activity. We also identified a high prevalence of Rickettsia raoultii infections in adult D. reticulatus, reaching up to 84.21%. Additionally, 9.52% of ticks were found to be infected with R. helvetica and 4.76% with Anaplasma phagocytophilum. Furthermore, our genetic analyses confirmed the identity of D. reticulatus in the Subcarpathian region, aligning with haplotypes found in other regions of Poland, Czechia, Croatia, and Portugal. In conclusion, our study suggests that the surveyed region represents the current boundary of the compact range of D. reticulatus in Poland in which this tick species exhibits low genetic diversity and a narrow spectrum of detected TBPs.

Elizabethkingia miricola is an emerging nosocomial pathogen responsible for meningitis, sepsis, urinary tract infection, pneumonia, and joint infection in humans. These pathogens were also reported to be causal agents for meningitis-like disease in cultured frogs, which displayed high infectivity, mortality, and significant loss. In July 2023, 10 outbreaks of infectious meningitis-like disease in bullfrogs occurred in Tangshan area. To determine the causal agent, 70 diseased frogs from 10 farms were collected for etiological identification. Gram-negative bacilli were isolated from the brain and liver of sick bullfrogs and identified as members of E. miricola by biochemical characterization and 16S rRNA sequencing analysis. A total of 42 strains of E. miricola were isolated and further determined as the etiological agent by reproducing neurological symptoms and deaths in an artificial infection test. A representative isolate, HBTS-1, was picked up for the pathogenicity test, and the data showed that this stain was highly pathogenic to bullfrogs with an LD₅₀ of 3.7 × 10⁵ CFU. Notably, the isolate also showed high pathogenicity to 5-day-old suckling mice, with an LD₅₀ of 3.1 × 10⁶ CFU, indicating its potential threat to mammals. Moreover, all the 42 E. miricola isolates showed resistance to multiple antibotics without an apparent inhibition zone observed in the test, making the choice of antimicrobial therapy challenging. These novel findings prioritized E. miricola as an important zoonotic agent, which may provide a reference for human medicine.

Canine coronavirus (CCoV) is a common agent of gastroenteritis in dogs, although some variants have been found associated with systemic and often fatal diseases. Distinct genotypes (CCoV-I and CCoV-II) and subgenotypes (CCoV-IIa and CCoV-IIb) are worldwide distributed. In Italy, CCoV infections have been occasionally evaluated, but information about the molecular epidemiology and the genomic features of currently circulating strains is limited. This study reports the detection and molecular characterization of CCoV strains from samples collected from 284 dogs in Italy between 2019 and 2021. CCoV RNA was detected in 39 (13.7%) dogs, as a single viral agent (5 animals, 12.8%) or with other viral pathogens (canine parvovirus types 2a/2b/2c; canine adenovirus type 1; norovirus GIV.2) (34 animals, 87.2%). A total of 48 CCoV strains were detected either alone (CCoV-I: 51.3%, CCoV-IIa: 20.5%) or in copresence (CCoV-I and CCoV-IIa, 23.1%); surprisingly, CCoV-IIb was not identified in this study. Five clusters of CCoV-I were detected, and their spike gene sequences showed the highest nucleotide identities with CCoV-I strains collected from Greece in 2008/2009 and from China in 2021. CCoV-IIa spike gene sequences (three variants) had the highest nucleotide identities with CCoV-IIa strains collected in Greece in 2008/2009 and in Italy in 2009/2011. Given the high CCoV diversity and the variable pathogenicity potential, we underline the need of further surveillance studies to increase our understanding of the epidemiology and evolution of these viruses.

Farm biosecurity has gained increasing attention worldwide during the last decades because of its role in reducing the occurrence of diseases and improving animal performance. Recently, recommendations to reinforce the concept of farm biosecurity in lower- and middle-income countries have been advised. Therefore, this review aims to provide a comprehensive description of the methods and tools used to assess biosecurity compliance in livestock farms in Africa and formulate recommendations. The present review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis extension for scoping reviews guidelines. Peer-reviewed studies reporting biosecurity assessment in poultry, cattle, pig, goat, or sheep farms in Africa were included. Five databases were searched with no date restrictions. A total of 41 studies across 17 countries were finally selected. Selected studies were all published after 2008, and an increasing trend in the number of papers published per year was noticed. In total, 41 different methods for biosecurity assessment were found to be used in African countries, meaning that even within the same country, the same animal species, and the same farming system, different methods were utilized. In many papers, the methods used for biosecurity evaluation were poorly described. In addition, during the biosecurity assessment, measures related to the purchase of laying hens, egg transport and management, calves, calving and dairy management, and nursery units were almost not considered. These measures should be contemplated in future studies since they are related to important risk factors for the introduction and dissemination of infectious diseases. Interestingly, some measures not considered in European biosecurity tools were identified in the selected studies. The observed high difference in methods used may be due to the lack of regulations on biosecurity in African countries; therefore, the authors recommend the development and implementation of a harmonized and contextualized method for the assessment of biosecurity in livestock farms in Africa.