National Food Safety and Quality Service

Infection of backyard and poultry with low pathogenicity avian influenza LPAI A(H5N2) viruses has occurred in Mexico since 1994, and the first human infection caused by this influenza virus was detected in 2024. Since its emergence in the Americas, frequent reassortments between high pathogenicity avian influenza HPAI A(H5N1) and LPAI viruses has occurred. In September 2025, the Instituto Nacional de Enfermedades Respiratorias of Mexico City identified an unsubtypeable influenza A virus infection in a young adult patient later determined to be a reassortant HPAI (H5N2) virus with a clade 2.3.4.4b HA. We analyzed clinical and epidemiologic data from this patient. Respiratory samples were tested for influenza RT-qPCR assays. Genomic sequence and phylogenetics analyses were performed to provisionally assign a new genotype to the novel HPAI A(H5N2) reassortant virus. The patient presented with fever and tachypnea, later developed hemoptysis and thoracic pain, with oxygen saturation decreasing to 70%. CT scan showed bilateral ground-glass opacities consistent with diffuse alveolar hemorrhage and zones consistent with consolidation. Clinical improvement was observed and the patient was discharged. Through viral complete genome analysis, we identified an HPAI A(H5N2) virus with genes from both clade 2.3.4.4b A(H5N1) viruses similar to those detected in North America during 2022-2023 and genes from the LPAI A(H5N2) viruses detected in Mexico during 2024. This is the first ever laboratory-confirmed human infection caused by an HPAI A(H5N2) virus infection, suggesting a new genotype provisionally classified as B3.14. The relationship of the virus with the severity of illness remains unknown.

Bovine purified protein derivative (PPD-B), a crude protein extract from Mycobacterium bovis cultures, has been the standard reagent for delayed-type hypersensitivity (DTH) testing in cattle, but its undefined composition and variability compromise reproducibility and specificity. To address these limitations, we developed and evaluated RRbTB-E, a recombinant fusion protein comprising ESAT-6, as a defined alternative for skin testing. RRbTB-E was produced in Escherichia coli, purified by affinity chromatography, and characterized by SDS-PAGE and Western blot. In M. bovis-sensitized guinea pigs, RRbTB-E induced robust DTH reactions comparable to PPD-B, with consistent performance across six independent experiments and long-term stability after storage at 4-8 °C for more than 900 days. Furthermore, RRbTB-E did not induce significant reactions in non-sensitized or Mycobacterium avium-sensitized animals, confirming antigenic specificity. RRbTB-E also elicited DTH responses in Mycobacterium tuberculosis-sensitized guinea pigs. In naturally infected cattle, it triggered responses similar in magnitude to PPD-B, while remaining negative in non-infected animals. These findings support RRbTB-E as a stable, reproducible, and specific candidate for standardized intradermal testing in bovine tuberculosis diagnosis.

Bacillus thuringiensis is the most extensively studied entomopathogenic bacterium worldwide; however, its sublethal effects on beetles remain poorly characterized. The aim of this study was to evaluate the toxicity of a previously selected Argentine strain of B. thuringiensis on second-instar Alphitobius diaperinus larvae during an initial 14 days of exposure, and to assess its effects at day 14 and throughout the remainder of the life cycle until death. Three treatments were applied: control, LC30, and LC50. Larval, pupal, and adult weight and body surface area were recorded, and nutritional composition was quantified using colorimetric methods. Insect status was monitored every 48-72 h over a total period of 540 days, until the death of the last individual. Among the evaluated variables, statistically significant differences between control and treatment groups were detected in larval area and weight, in the survival analysis and in two nutritional components: total protein and lipid content per larva. Overall, the results demonstrate that initial sublethal exposure to B. thuringiensis induces chronic lethal effects with delayed mortality in A. diaperinus, indicating irreversible physiological damage. This provides valuable information not only for understanding the biology of this insect but also for stakeholders involved in the productive scaling of beetle-targeted bioinputs.

Resumen. Asphondylia websteri1,, es una nueva plaga en chiles2 en Sinaloa, México Se reporta la presencia de Asphondylia websteri Felt (Diptera: Cecidomyiidae) afectando al cultivo de chile Capsicum annuum L. en Sinaloa, México.

Las zoonosis son enfermedades transmisibles entre el ser humano y otros animales que comprometen la salud pública y la sanidad animal. La miasis es una enfermedad zoonótica provocada por larvas de moscas carnívoras y parásitas transmisibles entre seres humanos, especies productivas, especies domésticas y vertebrados silvestres, que invaden y destruyen el tejido vivo del que se alimentan.

Abstract Foot-and-mouth disease (FMD) is a highly contagious viral disease with major implications for livestock production, food security, and economic stability. In this study, we investigate the transmission dynamics of the 2001 FMD outbreak in Mar Chiquita, Argentina, using a spatially explicit modeling framework. Transmission kernels based on inter-farm Euclidean distances are developed to estimate the probability of between-farm transmission and to reconstruct the likely transmission network. Several kernel formulations are evaluated, and parameters are estimated using maximum likelihood estimation techniques. We further assess the influence of isolation interventions by incorporating time-dependent kernel modifications that reflect reduced transmission risk following farm visits. Local transmission potential is quantified through farmspecific reproduction numbers, and transmission pathways are inferred using Markov Chain Monte Carlo (MCMC) simulations. Our results show that controlling geographic proximity alone does not reliably mitigate transmission risk and that delayed intervention can sustain epidemic spread. The reconstructed transmission network reveals spatial clusters of infections and temporal patterns consistent with field observations. These findings highlight the importance of timely isolation, active surveillance, and spatial risk assessment for effective outbreak control. Highlights Spatial transmission modeling captures FMD spread across 65 farms in Mar Chiquita, Argentina. Distance-based kernel functions estimated from epidemic data quantify between-farm infection risk. MCMC simulations reconstruct high-resolution farm-to-farm transmission networks. Intervention strategies (e.g., isolation) effectively reduce transmission probability and local R0.

Abstract With 325 currently recognized species, Anastrepha (Diptera: Tephritidae) is the largest genus of fruit flies within the American tropics and subtropics. It also includes the most economically important pest species in the region, some that have invaded the US and others that remain serious threats to U.S. agriculture. As part of a large collaborative effort to better understand Anastrepha species diversity and interrelationships and to address the need for new genetic data for integrated identification systems, we developed a new phylogenetic tree of Anastrepha species and species groups from anchored hybrid enrichment phylogenomics to serve as a reference system and diagnostic data resource. We captured and analysed 293 orthologous nuclear loci for 728 Anastrepha individuals representing 237 species, as well as from seven outgroup Tephritidae. These data strongly support the monophyly of most of the previously recognized Anastrepha species groups, while also revealing new support for previously unknown relationships among species, some previously unassigned, and species groups. Our results confirm that the fraterculus cryptic species complex is polyphyletic and delimit 7–8 lineages, not all of which match the current morph concepts. They also suggest that the Mexican morph and Anastrepha zenildae Zucchi are conspecific. Our results provide a useful framework for understanding the history of this major radiation of fruit‐infesting flies and indicate the closest relatives of the pest species to give new perspective on their biology and behaviour. They also provide a large genome‐wide nuclear gene resource for potential use as identification markers and phylogenetic placement loci for pest and non‐pest species and populations.

As a significant zoonotic disease, rabies poses substantial economic challenges for the livestock sector, highlighting the need for effective wildlife monitoring as part of a One Health approach. This study documents the first case of paralytic rabies in a lowland tapir (Tapirus terrestris) at the Guaycolec Wildlife Station in Formosa, Argentina. The 12-year-old male tapir exhibited neurological symptoms, including limb paralysis and dysphagia, leading to its death. The rabies virus was confirmed through direct immunofluorescence, virus isolation in BHK-21 cells, and molecular diagnostics via real-time RT-PCR and conventional PCR. Antigenic variant 3, associated with Desmodus rotundus, was identified. Histopathological examination revealed non-suppurative encephalitis with lymphocytic perivascular cuffs, neuronal vacuolization, and acidophilic intracytoplasmic inclusion bodies in the grey matter. This case underscores the importance of expanded surveillance for non-traditional hosts, as it demonstrates the potential for rabies transmission in changing environments. The findings highlight the need to maintain epidemiological surveillance systems at the wildlife-livestock-human interface and to develop targeted control strategies to mitigate the spread of rabies, particularly in areas where vampire bat populations are subject to anthropogenic pressures. Comprehensive monitoring and early detection are essential for effective rabies management in both wildlife and urban contexts.

Surveillance of antimicrobial resistance (AMR) in Salmonella in livestock (poultry, pig, and cattle) is crucial to maintain food safety. Given the lack of information on the situation in livestock in Paraguay, the aim of this study was to determine the most frequent Salmonella serovars in poultry, pig and cattle sampled in slaughterhouses in the country in 2020-22 along with their AMR phenotypes using data from a national pilot program. Out of 1,161 samples collected from slaughtered animals originating from 189 farms nationwide, Salmonella was isolated from 91/384 (23.7%) samples from poultry, 52/390 (13.3%) from pigs and 6/387 (1.6%) from cattle. Seven serovars were identified in poultry, with Heidelberg being the most frequent (82.4% of 91 isolates), while the most frequent serovars in pigs were Panama (48.1%) and Typhimurium (38.5%), and only two serovars (Cerro and Braenderup) were identified in cattle. The proportion of resistant isolates ranged from extremely high (70-83% for nalidixic acid and tetracycline) and high (25-40% for nitrofurantoin and ampicilin) to low-moderate (8-18% for cefixime, cefotaxime, amoxicillin, and trimethoprim- sulfamethoxazole) and very low-low (<6% for ciprofloxacin and gentamicin) depending on the antimicrobial. Up to 23 different resistance profiles were found, ranging from pansusceptible (18/143 isolates) to resistance to 2-7 antimicrobials (median = 2), with the predominant serovars in poultry and swine typically being resistant to ≥3 antimicrobials. These results should be backed-up with genomic analyses to determine the genetic mechanisms involved in the resistance profiles observed in order to support coordinated actions for AMR surveillance and control in the country.