Àlex Cobos

Gastrointestinal disorders in poultry -as in any production animals - are a common cause of disease with potential negative impacts on animal health, welfare and productivity. The small and large i...

African swine fever (ASF) reemerged in free‐ranging wild boar in Catalonia, northeastern Spain, in November 2025, representing the first detection in Spain since 1994. We described the initial outbreak phase using surveillance data collected from 25 November 2025 to 23 February 2026. ASF virus (ASFV) positivity by real‐time quantitative polymerase chain reaction (qPCR) was estimated overall and by surveillance stream; mortality timing was reconstructed probabilistically from estimated death‐date intervals; and early front displacement was analyzed using leading‐edge cumulative minimum convex polygons (MCPs), linear and generalized additive models (GAMs), segmented regression, and directional modeling. Among 1483 wild boars with definitive qPCR results, 201 were ASFV qPCR‐positive, giving an overall qPCR positivity of 13.6% (95% confidence interval [CI] 11.9–15.4). Positivity was substantially higher in enhanced passive than in active surveillance (28.2% vs. 0.9%; positivity ratio [PR] 32.11, 95% CI 15.21–67.78; p < 0.001). A probabilistic cumulative mortality curve based on 198 positive carcasses indicated that, by the date of the first detected carcass, expected cumulative mortality had already reached 25.8 deaths (13% of reconstructed total mortality). Leading‐edge analysis estimated an apparent mean radial front‐displacement rate of 0.042 km/day (95% CI 0.029–0.055). The surveillance‐derived distance–time relationship was nonlinear, indicating that the apparent front‐displacement rate varied over the study period, with a segmented‐regression breakpoint at 119 days and higher apparent front‐displacement thereafter (0.106 vs. 0.021 km/day). The exploratory directional analysis indicated the fastest predicted advance toward the South–Southwest sector. These surveillance‐derived estimates describe the observed leading edge under the surveillance and control conditions operating during the study period and should not be interpreted as direct estimates of ASFV transmission speed. These findings support an adaptive, risk‐based response that prioritizes carcass search and removal and incorporates directional spread information to refine surveillance and zoning as the outbreak evolves. The analytical framework, combining reconstruction of estimated dates of death with simple descriptors of early epidemic spread, may support early epidemiological assessment of ASF incursions in other newly affected settings.

While the development of effective subunit vaccines against African swine fever (ASF) is ongoing, live attenuated vaccines (LAVs) remain the only current strategy capable of inducing robust protective immunity. However, potential biosafety concerns limit their implementation in the field. Thus, further research is required to develop optimized LAVs with better biosafety profiles. Both the ASF virus (ASFV) and derived LAVs suppress innate immune responses of macrophages, thereby limiting their contribution to the induction of protective immune responses. We hypothesized that adjuvants could restore the functionality of LAV-infected macrophages, allowing for a reduction in the vaccine’s effective dose and consequently minimizing the risk of adverse events. To test this hypothesis, we intranasally vaccinated pigs with a suboptimal dose of the LAV BA71ΔCD2, either alone or in combination with two adjuvants derived from the immunostimulatory bacterium Rothia nasimurium . The two immunostimulants enhanced the responsiveness of BA71ΔCD2-infected macrophages, which acquired features of antigen presenting cells. However, both adjuvants reduced the levels of ASFV-specific humoral and cellular responses induced by BA71ΔCD2, consequently decreasing the level of protection against a lethal challenge. Further in vitro analyses demonstrated that adjuvant-activated macrophages acquired an antiviral state, thereby reducing the replication capability of the LAV. Thus, the adjuvant-mediated decline in vaccine efficacy might result from a lower antigen production by infected cells. These results demonstrate that the use of adjuvants combined with ASFV-based LAVs will require a fine-tune manipulation of macrophages, enhancing their functionality while avoiding a significant inhibition of virus replication, reaching the required balance between the levels of viral antigens and innate immune responses to trigger a protective adaptive immunity.

Background/Objectives: Maternally derived antibody (MDA) levels of porcine circovirus 2 (PCV2) may eventually interfere with humoral response and vaccination efficacy. This study aimed to evaluate the efficacy of a ready-to-use PCV2d and Mycoplasma hyopneumoniae combined vaccine in piglets with different PCV2 MDA levels at vaccination in an experimental inoculation with a heterologous viral genotype. Methods: Forty-eight piglets were allocated into vaccinated (V) and non-vaccinated (NV) groups with high (H) and low (L) PCV2 MDA subgroups (H-V, H-NV, L-V, L-NV). At 3 weeks of age, the piglets received either one dose of vaccine or placebo. Five weeks later, all animals were intranasally challenged with a PCV2b inoculum. Body weight was registered at different time points. Blood samples, peripheral blood mononuclear cells and tracheobronchial lymph nodes (TBLN) were collected and used to assess viraemia, viral load, humoral and cellular responses and histological lesions. Results: The V group showed higher PCV2 antibody levels from challenge onwards, along with a lower percentage of viraemic pigs and reduced viral load in serum at 2 and 3 weeks post-challenge (wpc) and in TBLN tissues compared to the NV group. The H-V group had the highest antibody levels post-challenge, showed no detectable viraemia and had a lower overall amount of virus in tissues. The NV group (especially H-NV) exhibited increased levels of IFN-γ, IFN-α and TNF-α post-challenge. Conclusions: The tested vaccine elicited humoral and cellular immune responses and reduced viral presence in serum and tissues, demonstrating efficacy in a PCV2 subclinical infection model despite high MDA levels at the time of vaccination. Understanding both humoral and cellular immune responses according to different MDA levels can help design more effective vaccination strategies against PCV2.

Background/Objectives: Classical swine fever (CSF) continues to challenge global eradication efforts, particularly in endemic regions, where pregnant sows face heightened risks of vertical transmission following exposure to CSFV. Methods: This study evaluates the early protective efficacy of FlagT4G, a novel live attenuated DIVA-compatible vaccine. Pregnant sows were vaccinated at mid-gestation and challenged 14 days later with a highly virulent CSFV strain. Results: FlagT4G conferred complete clinical protection, preventing both maternal viremia and transplacental transmission. No CSFV RNA, specific antibodies, or IFN-α were detected in fetal samples from vaccinated animals. In contrast, unvaccinated sows exhibited clinical signs, high viral loads, and widespread fetal infection. Interestingly, early protection was observed even in the absence of strong humoral responses in some vaccinated sows, suggesting a potential role for innate or T-cell-mediated immunity in conferring rapid protection. Conclusions: The demonstrated efficacy of FlagT4G within two weeks of vaccination underscores its feasibility for integration into emergency vaccination programs. Its DIVA compatibility and ability to induce early fetal protection against highly virulent CSFV strains position it as a promising tool for CSF control and eradication strategies.

Cutaneous lesions suggestive of vasculitis and/or ischemic dermatopathy (ID) are anecdotally reported in canine leishmaniosis, and the clinicopathological features of these conditions have not been fully characterized. The objective of this case series was to describe six dogs with leishmaniosis and ID. In 5/6 dogs, leishmaniosis was diagnosed at the time of ID diagnosis, whereas in 1/6 dogs, ID developed during the first month of anti-Leishmania conventional treatment. One each of greyhound, Chihuahua, whippet, American bully, hound and mixed breeds were represented, and the median age at presentation was 6 years [2–8]. All patients presented high or very high levels of circulating anti-Leishmania infantum antibodies. The cutaneous lesions were multifocal alopecia with atrophic skin with hyper- or hypopigmentation (6/6), ulcers located on the extremities and trunk (3/6) and onychodystrophy (2/6). Histologically, ID was confirmed by the presence of follicular atrophy (faded follicles) (6/6), perivascular or interstitial lymphoplasmacytic dermatitis or panniculitis (6/6), collagen smudging (3/6), dermal fibrosis (3/6), lymphocytic interface dermatitis (3/6) and ulceration (3/6). Vasculopathy was observed in the superficial and mid-vascular plexuses in 4/6 dogs and characterized by the combination of some of the following lesions: vasocongestion, hemorrhagic foci, mild hyaline mural degeneration, thrombi and fragmented degenerating nuclear debris of neutrophils in the vascular wall. Moreover, myositis was observed in 1/6 cases. Leishmania-specific immunohistochemistry was positive in the skin of 4/6 cases. Leishmaniosis might be considered an underlying cause of ID in dogs. However, the immune mechanisms and pathogenesis need to be elucidated.

Porcine circovirus 3 (PCV-3) has emerged as a significant pathogen affecting global swine populations, yet its epidemiology and clinical implications remain incompletely understood. This retrospective study aimed to investigate the prevalence and histopathological features of PCV-3 infection in pigs from Switzerland, focusing on archival cases of suckling and weaner piglets presenting with suggestive lesions. An in-house qPCR assay was developed for detecting PCV-3 in frozen and formalin-fixed paraffin-embedded tissues, enhancing the national diagnostic capabilities. Histopathological reassessment identified PCV-3 systemic disease (PCV-3-SD) compatible lesions in 19 (6%) of archival cases, with 47% testing positive by qPCR across various organs. Notably, vascular lesions predominated, particularly in mesenteric arteries, heart, and kidneys. The study confirms the presence of PCV-3 in Switzerland since at least 2020, marking the first documented cases within the Swiss swine population. Despite challenges in in situ hybridization validation due to prolonged formalin fixation, the findings indicate viral systemic dissemination. These results contribute to the understanding of PCV-3 epidemiology in Swiss pigs, emphasizing the need for continued surveillance and further research on its clinical implications and interaction with host factors. Our study underscores the utility and limitations of molecular techniques in confirming PCV-3 infections.

African swine fever (ASF) is a deadly disease of swine currently causing a worldwide pandemic, leading to severe economic consequences for the porcine industry. The control of disease spread is hampered by the limitation of available effective vaccines. Live attenuated vaccines (LAVs) are currently the most advanced vaccine prototypes, providing strong protection against ASF. However, the significant advances achieved using LAVs must be complemented with further studies to analyze vaccine-induced immunity. Here, we characterized the onset of cross-protective immunity triggered by the LAV candidate BA71ΔCD2. Intranasally vaccinated pigs were challenged with the virulent Georgia 2007/1 strain at days 3, 7 and 12 postvaccination. Only the animals vaccinated 12 days before the challenge had effectively controlled infection progression, showing low virus loads, minor clinical signs and a lack of the unbalanced inflammatory response characteristic of severe disease. Contrarily, the animals vaccinated 3 or 7 days before the challenge just showed a minor delay in disease progression. An analysis of the humoral response and whole blood transcriptome signatures demonstrated that the control of infection was associated with the presence of virus-specific IgG and a cytotoxic response before the challenge. These results contribute to our understanding of protective immunity induced by LAV-based vaccines, encouraging their use in emergency responses in ASF-affected areas.

Background: Porcine circovirus 3 (PCV-3) is a recently discovered pathogen of swine that has been associated with several conditions. However, many questions remain unanswered regarding its infection, especially in terms of pathogenesis and disease impact. The aim of the present study was to retrospectively investigate the presence of PCV-3 genome by real time quantitative PCR (qPCR) and in situ hybridization (ISH) on selected formalin-fixed paraffin-embedded tissues of pigs affected by different clinical conditions and histological lesions. Materials and methods: Conditions investigated included porcine dermatitis and nephropathy syndrome (PDNS), periweaning failure-to-thrive syndrome (PFTS), congenital tremors type AII, reproductive disorders, and pigs affected by systemic periarteritis/arteritis, myocarditis, or encephalitis. Studied cases (n = 587) were investigated from a diagnostic database (n = 4162) that comprised samples collected within the period 1998–2021. From each condition/lesion, 10 to 12 cases were subsequently selected and tested by qPCR and ISH (72 cases total). Results: A total of 587 cases fulfilled inclusion criteria of the different studied conditions and were distributed among the seven groups. For the further selected cases, PCV-3 genome was found by qPCR in 12/12 periarteritis, 5/10 reproductive disease, 5/10 PFTS, 3/10 myocarditis, 1/10 encephalitis and 1/10 congenital tremor cases. PCV-3 was not found in any of the PDNS cases assessed. In periarteritis cases, tissues more commonly affected were mesenteric arteries and kidney. Reproductive disease cases associated to PCV-3 genome consistently displayed myocarditis. The lesions and labelling distribution of PFTS cases with presence of PCV-3 genome were comparable to those of the periarteritis group. qPCR and ISH yielded similar results within each studied case and were statistically comparable. Conclusion: Our results suggest that periarteritis is the hallmark lesion of PCV-3-SD, and that mesenteric lymph node and kidney appeared to be the most reliable organs to confirm the presence of PCV-3 genome in cases with periarteritis.

A surge in fowl adenovirus (FAdV) causing inclusion body hepatitis (IBH) outbreaks has occurred in several countries in the last two decades. In Spain, a sharp increase in case numbers in broilers and broiler breeder pullets arose since 2011, which prompted the vaccination of breeders in some regions. Our retrospective study of IBH cases in Spain from 2011 to 2021 revealed that most cases were reported in broilers (92.21%) and were caused by serotypes FAdV-8b and -11, while cases in broiler breeder pullets were caused by serotypes FAdV-2, -11, and -8b. Vertical transmission was the main route of infection, although horizontal transmission likely happened in some broiler cases. Despite the inconsistent and heterogeneous use of vaccines among regions and over time, the number of cases mirrored the use of vaccines in the country. While IBH outbreaks were recorded year-long, significantly more cases occurred during the cooler and rainier months. The geographic distribution suggested a widespread incidence of IBH and revealed the importance of a highly integrated system. Our findings contribute to a better understanding of FAdV infection dynamics under field conditions and reiterate the importance of surveillance, serological monitoring of breeders, and vaccination of breeders against circulating serotypes to protect progenies.