Gonzalo Fernández

Canine parvovirosis is a fatal disease state traditionally caused by canine parvovirus (CPV), which evolved from feline panleukopenia virus (FPV). While FPV was historically restricted to felids, FPV-like strains were recently reported to be causing clinical disease in dogs. This study aims to characterize an FPV-like strain detected in an eight-week-old unvaccinated female dog in Spain exhibiting hemorrhagic diarrhea and severe leukopenia. After fecal DNA isolation, a 1745-base-pair fragment of the VP2 gene was sequenced for phylogenetic and molecular analysis. Our results revealed that this strain shared high homology with local feline FPV strains; the sequence was clustered near to other FPV strains detected in dogs elsewhere. Molecular analysis identified an isoleucine-to-threonine substitution at position 101 (I101T) of the VP2 protein. This mutation, common in contemporary FPV and CPV variants, has been described as a structural modification that optimizes interaction with the canine transferrin receptor, suggesting a potential role in canine host adaptation. In conclusion, this study represents the first report in Spain of FPV associated with clinical gastroenteritis in dogs. These findings underscore the necessity of continuous genomic surveillance of these highly evolving viruses for monitoring host-switching events.

Canine parvovirosis is a fatal disease traditionally caused by canine parvovirus (CPV-2), which evolved from feline panleukopenia virus (FPV). While FPV was historically restricted to felids, FPV-like strains were recently reported causing clinical disease in dogs. This study aims to characterize an FPV-like strain detected in an eight-week-old unvaccinated female dog in Spain exhibiting hemorrhagic diarrhea and severe leukopenia. After fecal DNA isolation, a 1745 base pair fragment of the VP2 gene was sequenced for phylogenetic and molecular analysis. Our results revealed that this strain shared high homology with local feline FPV strains; the sequence was clustered near to other FPV strains detected in dogs elsewhere. Molecular analysis identified an isoleucine-to-threonine substitution at position 101 (I101T) of the VP2 protein. This mutation, common in contemporary FPV and CPV variants, has been described as a structural modification that optimizes interaction with the canine transferrin receptor, suggesting its essential role for canine host adaptation. In conclusion, this study represents the first report in Spain of FPV associated with clinical gastroenteritis in dogs. These findings underscore the necessity of continuous genomic surveillance of these highly evolving viruses for monitoring host-switching events and assessing the ongoing efficacy of current immunization strategies.

Epizootic hemorrhagic disease (EHD) is an emerging disease in Europe since it was first introduced in 2022 in Italy, Spain, and Portugal. The disease is traditionally considered less severe in cattle, but outbreaks have appeared with increasing frequency in the last decades. The outbreak in Spain coursed with numerous cattle farms reporting clinical disease. Our aim in this study was to evaluate the incidence of clinical disease in cattle farms from NW Spain and describe the clinical signs and their frequency. We investigated 29 cattle farms that reported EHD and estimated an incidence of farms with clinical signs of 6.2% ( n = 467) in the study area (range: 2.3%–33.3%). The mean incidence of clinical signs, mortality, and lethality rates were 8.9%, 1.7%, and 23.0%, respectively. Interestingly, mortality and lethality were significantly higher in dairy cattle than in beef (OR of 3.0 and 4.4, respectively). Oral lesions, dysphagia, and hoof problems were common clinical signs found in the study. Among all, the presence of tongue edema, dehydration, and dyspnea was associated with higher lethality rates. These results highlight a significant impact of EHD during the emergency. In fact, it must be noted that our data are based on passive surveillance, so true incidences are likely to be higher. The clinical signs and epidemiologic characteristics reported in this paper may contribute to understanding the clinical implications of the disease in cattle and help anticipate the effects of EHD virus (EHDV) introduction into naïve regions.

Vaccination against Porcine Circovirus Type 2 (PCV2) even over several years has proven as an insufficient measure to eradicate the infection from farms, possibly due to not producing sterilizing immunity. Viral persistence in the farm environment has been proposed as a possible cause of reinfection, and for that reason, the main objective of this study was to identify potential critical points where PCV2 could persist in farrow-to-wean farms which had been vaccinating piglets for years. Surface samples were collected from different farm facilities with and without animals and analyzed by qPCR to detect and quantify the viral load. Most of the samples taken in animal housing facilities tested negative (96.6%); however, PCV2 was more frequently detected in samples from the offices (37.5%), the farm staff (25%) and the perimeter (21%). These results indicate that PCV2 contamination is frequent in facilities despite the long-term use of vaccination programs. Therefore, PCV2 control programs should include more exhaustive cleaning and disinfection protocols in non-animal facilities, as well as the implementation of specific biosecurity measures in these areas to minimize the risk of PCV2 introduction from external sources.

Metastrongyloid and trichuroid cardiorespiratory nematodes of dogs and cats are considered emergent in several European countries, and an increase in the number and extent of endemic foci has been described. Since data on their prevalence are limited in this continent, faecal samples from new arrivals (365 dogs and 65 cats) at two animal shelters in North‐western Spain were analysed using both floatation and Baermann techniques. In order to confirm the microscopic identification of Metastrongylidae first stage larvae, molecular characterization based on the sequence of the ITS‐2 was performed. The possible influence of some variables such as the species, sex and age of the animals and the co‐infection with other gastrointestinal parasites on the prevalence of cardiorespiratory nematodes was analysed. The most prevalent metastrongylid was Aelurostrongylus abstrusus (15.4%) followed by Angiostrongylus vasorum (4.1%) and Crenosoma vulpis (1.1%). Regarding trichuroids, Eucoleus aerophilus and/or Eucoleus boehmi eggs were detected in 28 dogs (7.7%) and four cats (6.2%). Almost all animals positive to cardiorespiratory nematodes (86.8%) were co‐infected with gastrointestinal parasites. The prevalence of Metastrongylidae and respiratory trichuroids was significantly higher in dogs co‐infected with Taenia spp. and Toxocara canis or Giardia duodenalis and Sarcocystis spp., respectively. In cats, a significant higher prevalence of Metastrongylidae nematodes was found in animals co‐infected with Toxocara cati. Our results reveal that cardiorespiratory nematodes are common in companion animals from north‐western Spain, showing higher prevalences than those previously reported from this country. This investigation represents the first report of C. vulpis, E. aerophilus and E. boehmi in dogs from Spain. The identification of a number of zoonotic parasites is of public health concern. Our results indicate that these nematodes should be included in the differential diagnosis of dogs and cats from north‐western Spain showing respiratory or cardiac clinical signs.

Enterotoxigenic Escherichia coli (ETEC) is one of the major pathogens involved in neonatal calf diarrhoea (NCD) causing high economic losses in dairy farms. Antibiotic treatment is common in cases of systemic illness caused by NCD, but antimicrobial susceptibility tests (AST) are usually not performed. Thus, the aim of this study was to characterize the antimicrobial susceptibility of ETEC strains obtained from calves with diarrhoea between 2018–2020. Faecal samples (n = 420) were analyzed to detect the typical ETEC virulence factors F5 and STa. Positive samples were cultured to identify and isolate ETEC strains (n = 41) and ASTs were performed. Our results are alarming since ETEC strains resistant to three or more families of antimicrobials were detected in all isolates. Only four antibiotics (ceftiofur, cefoperazone, cefquinome and gentamicin) presented efficacy against more than 90% of the ETEC strains, while the other ten antibiotics were effective against less than 40% of the strains. In addition, a high number of strains were resistant to most first-line antimicrobials used in veterinary practice. For this reason, when ETEC infection is suspected, an AST must always be performed to select the most appropriate antimicrobial in each case and to avoid the emergence of new resistance mechanisms.

Porcine Circovirus Type 2 (PCV2) and Mycoplasma hyopneumoniae are economically important pathogens in swine farms. Vaccination is the main preventive measure for both infections. In order to test two ready-to-use bivalent vaccines, 646 piglets from a herd actively infected with both pathogens were stratified according to the sow parity number and randomly assigned to three groups: A and B were vaccinated with two different vaccines, respectively, while C remained as the unvaccinated control. Vaccine efficacy was assessed based on the weight, average daily weight gain (ADWG), degree of lung lesions, presence of PCV2 viremia by qPCR and presence of PCV2 and M. hyopneumoniae antibody levels by ELISA. Our data revealed that the sow parity did not influence the vaccine outcomes. Good results for most of the analyzed parameters were observed in both vaccinated groups. ADGW and final weight were higher and lung lesions were less evident in both vaccinated groups than in the control one, but only Group A showed a significant improvement. PCV2 viremia was not detected in Group A, but it did appear in Group B coinciding with its peak in Group C. Finally, both the PCV2 and M. hyopneumoniae serological patterns differed depending on the employed vaccine.

Myxoma virus (MYXV) is the aetiological agent of myxomatosis, a systemic, mostly lethal disease that affects European rabbits. Vaccination against it, although widespread, has not been completely effective and disease outbreaks still take place on farms which carry out vaccination programmes. Since some of these cases have been attributed to airborne transmission or the spread of the virus via inanimate vectors, the aims of this study were to determine MYXV contamination levels and distribution in the environment of vaccinated farms and to ascertain whether the detected virus corresponded to field strains. For that, environmental samples from several areas, tools and employees from four (three infected and one uninfected) rabbitries were taken and analysed by qPCR. MYXV was detected in the environment of all the infected farms, whereas all the samples from the non-infected farm were negative. Furthermore, all the positive samples contained viral DNA compatible with field strains of the virus. These results lead us to believe that the administration of currently available commercial vaccines does not prevent infected animals from shedding the field virus. Moreover, viral DNA was also found in items that are not in direct contact with the animals, which could play a role in the transmission of the infection throughout the farm and to other farms. Therefore, this study proves that current vaccination schemes on their own are not sufficient to prevent this disease and should be accompanied by adequate biosecurity measures.

Air and surfaces of swine farms are the two alternative samples to obtain information about the health status of the herd. The aim of this study was to assess air and surface sampling for the detection of porcine circovirus type 2 (PCV2) in vaccinated and unvaccinated fattening farms, studying the relationship between the viral load in these samples with the viremia at herd level. Three swine fattening batches (one unvaccinated; two vaccinated) were monitored at 10, 12, 14, 16 and 18 weeks old; at each stage, blood, air and different surfaces were sampled and analysed by qPCR. In all herds, PCV2 was detected in all types of samples. Whenever viremia was detected, PCV2 was also detected in air and surface samples, even in those cases with a low estimated prevalence (1.6%); moreover, in two out of the three herds, PCV2 was detected in air and surface samples earlier than in the blood of the sampled population. In addition, a good correlation between the viremia of pig population and the PCV2 load in air and surface samples was found in both cases (τ = 0.672 and 0.746, respectively; p <0.05). These results show that air and surface samples could be useful tools to monitor PCV2 infection, being suitable for detecting the virus in cases of low prevalence and even before pigs develop viremia; therefore, these sampling techniques would speed up the implementation of the required measures to prevent productive and economic losses due to PCV2 infection.