Gustavo Hernández-Vidal

Cochliomyia hominivorax, the main etiological agent of traumatic myiasis in the New World, continues to have significant health and economic impacts due to its effects on animal health, livestock production and public health in affected regions. Although conventional control strategies, including the Sterile Insect Technique and chemical insecticides, have substantially reduced its distribution, concerns regarding insecticide resistance, environmental impacts, and recent re-emergence events underscore the need for sustainable alternative control approaches. This review summarizes current advances in the use of EOs and plant-derived bioactive compounds for the management of myiasis-causing flies, with particular emphasis on C. hominivorax, and discusses the emerging role of nanocarrier-based delivery systems in enhancing their biological performance. EOs and their major constituents exhibit larvicidal, ovicidal, adulticidal, repellent, and oviposition-deterrent effects through multiple mechanisms that disrupt essential physiological and developmental processes in insects. Several EOs have shown promising activity against C. hominivorax larvae; however, their practical application is often limited by their high volatility, low aqueous solubility, and physicochemical instability. Nanodelivery systems, including nanoemulsions, polymeric nanoparticles, and solid lipid nanoparticles, offer effective strategies to improve the stability, bioavailability, controlled release, and overall efficacy of plant-derived bioactive compounds. Current evidence indicates that nanodelivery systems enhance the stability and insecticidal efficacy of EOs while reducing the concentrations required to achieve biological activity, supporting their potential for the prevention and treatment of C. hominivorax myiasis. Nevertheless, further in vivo and field studies are required to validate their practical application.

Encephalitozoon cuniculi is a zoonotic mycotic pathogen that infects rabbits. When the host becomes infected, spores in the brain parenchyma cause severe granulomatous meningoencephalitis. The mechanisms by which spores reach the CNS are poorly understood. We divided 27 white New Zealand rabbits into 2 groups: 15 infected orally with 10 ⁶ spores and 12 uninfected controls. Animals were euthanized at 30 d post-infection (dpi). Histologically, spores were present within brain blood vessels at 30 dpi. To our knowledge, the localization of free E. cuniculi spores has not been demonstrated previously within blood vessels in the brain of rabbits.

Rhabdomyosarcomas are rarely reported in reptiles, and this is, to the authors′ knowledge, the second one described in a tortoise. A male captive terrestrial tortoise of at least 11 years of age ( Gopherus berlandieri ) was presented with a reddened growth of the distal aspect of the right posterior limb, measuring approximately 4.5 cm. The affected limb was amputated, and radiologic evaluation of the sample revealed osteolysis of the phalanges and peripheral inflammation. Initial histopathologic examination showed a nonencapsulated, high cellularity neoplastic lesion conformed by poorly differentiated cells with unappreciable or scant cytoplasm and a nucleus with one or two prominent nucleoli. Occasionally, bigger, eosinophilic, strap cells with evident cross‐striations were present and stained red by Masson′s trichrome stain. The tissue resulted negative for immunohistochemistry staining with MyoD1 and myogenin markers, yet transmission electron microscopy showed electron‐dense bands compatible with Z‐band remains which constitutes a high certainty criterion for the diagnosis of rhabdomyosarcomas. This case highlights the advantages of ultrastructural studies over the more commonly performed immunohistochemistry studies in the diagnosis of neoplasia in nondomestic animals.

Cannabidiol (CBD), a phytocannabinoid derived from Cannabis sativa, has demonstrated therapeutic potential across various diseases, including cancer. This study evaluates the cytotoxic effects of CBD on three human cancer cell lines (HeLa, MDA-MB-231, and CaCo-2) and two non-cancerous cell lines (HaCaT and HUVEC) used as a control. Cells were treated with CBD at concentrations of 5, 10, and 20 µM for 24, 48, 72, and 96 h. Cytotoxicity was assessed using MTT assays, nuclear morphology was evaluated via DAPI staining, and cell death mechanisms were analyzed through flow cytometry with apoptosis/necrosis markers. The LC50 values at 24 h were determined as follows: HeLa (9.4 µM), MDA-MB-231 (10.3 µM), and CaCo-2 (4.3 µM). CBD treatment induced morphological changes characteristic of cell stress and death in cancer cells, observed by optical microscopy after 24, 48, 72, and 96 h of exposure. These findings highlight the potential of CBD as an adjunctive therapeutic agent for cancer treatment versus non-malignant cells.

Controlling Rhipicephalus microplus is currently one of the main challenges in livestock farming due to the significant economic losses it causes. Traditionally, managing this parasite has been based on the use of synthetic ixodicides, among which fipronil has proven to be highly effective. However, its low water solubility and the limitations of commercially available formulations can affect the bioavailability of this compound, favoring the emergence of resistance in tick populations. In this context, fipronil-loaded nanoparticles were developed using the Eudragit^® E PO polymer (NP_F) (Helm, Naucalpan, Mexico, Mexico), which were physicochemically characterized and evaluated against fipronil-susceptible R. microplus larvae. NP_F had an average size of 143.43 ± 1.88 nm, a polydispersity index (PDI) of 0.162 ± 0.01, a ζ (P ζ) of 21.16 ± 0.54, an encapsulation percentage (%E) of 7.36 ± 0.30, and an encapsulation efficiency percentage (%EE) of 66.28 ± 3.5%. Free fipronil showed an LC₅₀ of 0.582 µg/mL and an LC₉₀ of 2.503 µg/mL against R. microplus. The NP_F formulation showed an LC₅₀ of 0.427 µg/mL and an LC₉₀ of 2.092 µg/mL. These results suggest that incorporating fipronil into nanoparticles improves its ixodicide efficacy, positioning it as an innovative and promising alternative for the development of effective tick control formulations.

Cannabidiol (CBD), a phytocannabinoid derived from Cannabis sativa, has demonstrated therapeutic potential across various diseases, including cancer. This study evaluates the cytotoxic effects of CBD on three human cancer cell lines (HeLa, MDA-MB-231, and CaCo-2) and two non-cancerous cell lines (HaCaT and HUVEC) used as a control. Cells were treated with CBD at concentrations of 5, 10, and 20 µM for 24, 48, 72, and 96 h. Cytotoxicity was assessed using MTT assays, nuclear morphology was evaluated via DAPI staining, and cell death mechanisms were analyzed through flow cytometry with apoptosis/necrosis markers. The LC50 values at 24 h were determined as follows: HeLa (9.4 µM), MDA-MB-231 (10.3 µM), and CaCo-2 (4.3 µM). CBD treatment induced morphological changes characteristic of cell stress and death in cancer cells, observed by optical microscopy after 24, 48, 72, and 96 h of exposure. These findings highlight the potential of CBD as an adjunctive therapeutic agent for cancer treatment versus non-malignant cells.

The growing threat of antibiotic-resistant Gram-negative bacteria highlights the urgent need for innovative, non-bactericidal therapeutic strategies. Quorum-sensing (QS) inhibition has emerged as a promising approach to attenuate bacterial virulence without exerting selective pressure. This study evaluated the antimicrobial, anti-QS, and antibiofilm properties of aqueous extracts from five medicinal plants native to northeastern Mexico: Gymnosperma glutinosum, Ibervillea sonorae, Larrea tridentata, Olea europaea, and Tecoma stans. Disk diffusion and violacein quantification assays using Chromobacterium violaceum demonstrated significant QS inhibition by G. glutinosum and T. stans, with violacein reductions of 60.02% and 52.72%, respectively, at 40 mg/mL. While L. tridentata and O. europaea exhibited antibacterial activity, I. sonorae showed no growth or pigment inhibition but achieved the highest biofilm disruption (89.89%) against Salmonella typhimurium. UPLC-MS analysis identified chlorogenic acid, kaempferol, and D-(−)-quinic acid as major constituents, compounds previously associated with QS modulation. These findings highlight the potential of traditional Mexican plant species as sources of QS inhibitors and bio-film-disrupting agents, supporting their further development as alternatives to conventional antibiotics.

In February 2024, while conducting surveillance for novel respiratory viruses, we studied four beef cattle farms near Monterrey, Mexico. Nasal swabs were collected from sick and healthy beef cattle along with 3 h aerosol samples. None of the samples had molecular evidence of influenza A viruses. Three (8%) of thirty-six nasal swabs collected from the four farms and four (33.3%) of the twelve bioaerosol specimens had molecular evidence of influenza D virus. Five sick cow nasal swabs and one bioaerosol sample on a single farm had molecular evidence of rodent coronavirus-like (RCoV), an alphacoronavirus. Three (60%) of the five RCoV-positive cattle nasal swabs also had molecular evidence of influenza D. Attempts to isolate the RCoV in Vero-E6, LLC-MK2, MDBK, and L-2 cells were unsuccessful. However, we were able to assemble ~60% of the RCoV genome using next-generation sequencing. The six RCoV-positive samples clustered with RCoV strains identified in China in 2021. During the last 12 months, we have studied an estimated 478 dairy and beef cattle nasal swabs on 11 farms in the US and Mexico, and these RCoV detections are the first we have encountered. While feed contamination cannot be ruled out, given the propensity of CoVs to jump species and that we detected RCoV only in the noses of sick cows on this one farm, we are concerned that these findings could represent an isolated RCoV spillover event. With this report, we are alerting veterinarians and cattle farm owners of our observations that RCoV may be a new cause of bovine respiratory disease.

A short‐tailed female bat ( Carollia perspicillata ), 1 year old, died without apparent signs of the disease while on display at an amusement park in the Municipality of Montemorelos, Nuevo León, Mexico. Amphophilic nuclear inclusion bodies were observed in the intestinal epithelia, corresponding to the virus of the adenovirus genera. Although there have been no reported adenovirus cases of this bat species in Mexico, through an anatomopathological study and support from the microscopic, ultrastructural, and molecular findings of intestinal lesions, a diagnosis of enteritis caused by Adenovirus Type 2 was made. To the authors’ knowledge, the case described herein is the first report of infection by Adenovirus Type 2 in a short‐tailed bat in Mexico.