In Mexico, bullfrogs (Lithobates catesbeianus) are produced as gourmet food. However, bullfrogs can be carriers of pathogens because the frogs' preferred living conditions occur in stagnant water. The present study aimed to identify bacteria that cause foodborne diseases or are associated with human diseases. For molecular identification, based on the sequential analysis by 16S rRNA or rpoD was conducted on all isolates obtained from bullfrog. A total of 91 bacterial isolates were obtained from bullfrogs; 14 genera and 23 species were identified, including Acinetobacter johnsonii 16.5%; Aeromonas media 14.3%; Aeromonas veronii 13.2%; Providencia rettgeri 7.7%; Citrobacter freundii 6.6%; Aeromonas caviae 4.4%; Aeromonas hydrophila and Elizabethkingia ursingii 3.3%; Pseudomonas stutzeri, Raoultella ornithinolytica, and Shewanella putrefaciens 2.2%; Acinetobacter guillouiae, Acinetobacter pseudolwoffii, Citrobacter portucalensis, Citrobacter werkmanii, Edwardsiella anguillarum, Klebsiella michiganensis, Kluyvera intermedia, Kocuria rosea, Myroides odoratimimus, Myroides odoratus, Proteus sp., and Proteus hauseri 1.1%. In this study, 49.4% of the isolates obtained cause foodborne disease, 19.8% are bacteria that play an important role in the spoilage of food, 5.5% of isolates have nosocomial significance, 13.2% of bacteria are considered to be pollutants of the ecosystem, and in the case of A. salmonicida and Edwardsiella anguillarum (12.1%) to have a negative impact on aquaculture. Acinetobacter pseudolwoffii and Citrobacter portucalensis have not been reported to cause disease. Lastly of these isolates, 97.8% (89/91) can cause disease by food consumption or by direct contact for immunocompromised persons. The presence of these bacteria in bullfrogs represents a significant problem for human health. There is evidence that these microorganisms are pathogenic and frogs may also be reservoirs.

Tilapia has a high socioeconomic value in many countries worldwide. However, it has been identified as a zoonotic parasite reservoir. A systematic literature search and meta-analysis were carried out in order to estimate the global prevalence of zoonotic parasites that affect tilapia. The search was performed by three field experts to avoid reviewer bias. Polled prevalence was estimated using a logistic-normal random-effect regression model in the R software. We dealt with the heterogeneity among studies through subgroup analysis, taking into account the continent, country, genus of the host, parasite taxonomic group, sample origin, and type of diagnostic test as moderator variables. Fifty-two eligible articles were identified covering five tilapia genera with a pooled prevalence of 0.14 (95% CI: 0.10–0.20) showed significant heterogeneity (I² = 98.4; p < 0.001). The subgroup analysis revealed that the most affected host was Sarotherodon, with a prevalence of 0.42 (95% CI: 0.22–0.65). Cestode was the taxonomic group with the largest prevalence (0.40; 95% CI:0.32–0.48), followed by amoeba (0.24; 95% CI: 0.16–0.35) and nematode (0.22; 95% CI: 0.11–0.38), among which, Schyzocotyle spp., Opistorchis spp., Gnathostoma spp. and Vermamoeba spp. have an impact on public health. Significant differences (p < 0.004) were found among continents and countries, with the highest value of prevalence detected in the African continent (0.28; 95% CI: 0.20–0.37), specifically in Tanzania (0.56; 95% CI: 0.22–0.87) and Egypt (0.43; 95% CI: 0.20–0.55). The origin of samples had a significant effect (p < 0.0001) on the detected prevalence, especially from those that showed the highest prevalence (0.24; 95% CI: 0.17–0.33). Finally, there were no differences in prevalence according to the diagnostic test (p = 0.97). Our results provide useful information on the development of epidemiological programs for the control of zoonoses associated with parasites in tilapia and in the design, planning, and implementation of future research.

Wild boars (Sus scrofa) were introduced in Mexico for sport hunting and meat trading for human consumption, but the available data regarding their role in pathogen transmission are limited. This research and field work aimed to identify the helminths of the wild boar produced in three units of conservation management and sustainable use of wildlife placed in the eastern economic region of Mexico. Samples of feces and serum were collected from 90 animals that came from three different ranches. Stool examination and antibody determination to Fasciola hepatica, Taenia crassciceps, Ascaris suum, Toxocara canis (ELISA), and Trichinella spiralis (Western blot) were performed. In addition, 30 diaphragm samples from one ranch were obtained for artificial digestion. Eggs of Strongyloides sp. (72.2%), Metastrongylus sp. (57.7%), Oesophagostomum sp. (53.3%), and Trichuris sp. (37.7%) were found in addition to oocysts of Eimeria sp. (75.6%). Antibodies to Fasciola (8.9%), Taenia (4.4%), Ascaris (32.2%), Toxocara (20%), and Trichinella (5.5%) were found. The eggs of Strongyloides and Oesophagostomum were associated to female hosts. One nematode larva was found by artificial digestion. This is the first report to identify helminths from wild boars in Mexico. In addition, this study identifies the potential risk of the wild boar as a transmission channel of parasites that can have an impact on public health.

The genus Aeromonas is a group of bacteria that is widely distributed in water bodies and belongs to the normal intestinal microbiota of aquatic and terrestrial animals. In the present work, rainbow trout fingerlings were experimentally infected by an immersion bath with different Aeromonas species. Subsequently, the behavior of the infected groups was observed and recorded. Infected fingerlings were evaluated by histopathology. The highest percentages of hyperpigmentation (18.88%) and inappetence (47.7%) were observed in fish infected with A. salmonicida, while abnormal swimming (83.33%) was recorded in fish infected with A. bestiarum. In histopathological findings, the highest percentages were observed in the olfactory epithelium (50.0%) for A. lusitana and A. salmonicida (41.1%)-infected fish. While, in the nervous system, the cerebral hemispheres (31.1%) in A. media-infected fish and the oblongata medulla (40.0%) in the A. bestiarum-infected fish presented the highest percentages. Meanwhile, A. salmonicida and A. bestiarum have the highest pathogenicity and virulence based on the histopathological findings in the olfactory epithelium and nervous system. Due to the proximity of the olfactory epithelium with the nervous tissue, it is possible that the infection generated by the Aeromonas species and the histopathological findings in the nervous tissue are reflected in different behavioral changes that suggest differences in the pathogenicity and virulence of the bacteria.

Overexploitation has led to a rise in pathogenic bacteria within aquaculture, increasing reliance on antibiotics, and developing microorganism resistance. This situation underscores the need to explore alternatives with a reduced ecological impact. Metabolites derived from essential oils have demonstrated antimicrobial properties that can inhibit or diminish the activity of various microorganisms. In this study, the antimicrobial efficacy of cinnamon (Cinnamomum zeylanicum), tea tree (Melaleuca alternifolia), and thyme (Thymus vulgaris) essential oils against pathogenic bacteria (Aeromonas, Pseudomonas, Shewanella, Comamonas, Vibrio, Acinetobacter, and Empedobacter) isolated from tilapia (Oreochromis spp.) brooded in Hidalgo State, Mexico, were investigated. Diffusion tests were conducted using discs infused with 12 different antibiotics and discs infused with essential oils at concentrations of 15, 10, and 5 μL each. Minimal inhibitory concentration tests were performed using a 96-well microplate format. All bacterial strains exhibited multi-resistance to various antibiotics; however, thyme and cinnamon effectively inhibited the tested bacteria at the lowest concentrations, while tea tree oil was the least effective. The findings suggest the potential incorporation of thyme and cinnamon as an alternative prevention to decrease the use of antibiotic treatment.

We study the kinetics of eosinophils during the development of the cellular infiltrate surrounding the nurse cell of Trichinella spiralis (T. spiralis) in experimentally infected mice. Male CD1 mice were experimentally infected with 50 viable muscle larvae of the MSUS/MEX/91/CM-91 T. spiralis strain. Tongues and diaphragms were obtained daily from days 13 to 39 post infection. Diaphragms were compressed and subjected to Giemsa stain. Tongues were histologically sectioned and stained with erythrosine B or hematoxylin and eosin. The cellular infiltrate and the nurse cell-larva complex were detected by optical microscopy since day 16 post infection. The size of the larva increased exponentially during the course of the infection. The kinetics of eosinophils showed a multimodal trend, with a bimodal predominance. The maximum peaks were reached on days 21 and 27 post infection. The results of this study demonstrate that eosinophils occur abundantly in two transcendent moments of the T. spiralis life cycle: first, when the stage 1 larva invades the myocyte and second when the nurse cell-larva complex has been fully developed. These results help one to understand the immunobiology of T. spiralis, highlighting the importance of eosinophils in the survival of the larva in skeletal muscle. Further studies are needed to characterize the cell populations that comprise the cellular infiltrate during the development of the mother cell.