Evaluation of new Toxocara canis chimeric antigens as an alternative to conventional TES-Ag for anti-Toxocara antibodies detection

Cloning, bioinformatics analysis, and expression of the ubiquitin 2 (ubq-2) gene from the dog roundworm Toxocara canis

Toxocariasis, caused by the dog roundworm Toxocara canis, is a globally distributed zoonotic parasitic disease that poses a significant threat to veterinary and public health. The ubiquitin plus an L40 ribosomal protein (UBQ-2) in parasites plays a crucial role in protein degradation and meiotic divisions, thereby affecting parasite development, survival, and parasite-host interactions. In this study, we identified for the first time a full-length cDNA encoding the UBQ-2 protein from the T. canis-omic dataset, called Tcubq-2. After cloning and sequencing, we conducted sequence analysis and structural modeling of TcUBQ-2 using online bioinformatics tools. The recombinant TcUBQ-2 protein (rTcUBQ-2) was prokaryotically expressed and subjected to Western blot analysis to assess its antigenicity and immunoreactivity. Additionally, we performed immunolocalization of the endogenous protein in adult T. canis and evaluated its serodiagnostic potential using sera from naïve and infected mice and dogs. Our results showed that the complete cDNA sequence of Tcubq-2 was 387 bp in length and encoded a polypeptide of 128 amino acids, lacking both an N-terminal signal sequence and a transmembrane domain. Sequence and phylogenetic analyses showed that TcUBQ-2 shared the closest genetic distance with its homologs in Parascaris univalens and Ascaris suum. Real-time quantitative PCR and Western blotting revealed an expression peak of TcUBQ-2 in the intestine-hatched second-stage (L3) larvae compared to other developmental stages of T. canis. Tissue localization of endogenous TcUBQ-2 revealed its broad distributions in the body wall, muscle, gut epithelium, and microvilli of adult T. canis, with gender-specific expression in the uterus, ovary, and non-embryonated eggs of females. Based on its strong immunogenic properties, a recombinant TcUBQ-2 (rTcUBQ-2)-based ELISA was established and exhibited a sensitivity of 100% and a specificity of 95.8% to detect anti-T. canis mouse sera and a sensitivity of 79.2% and a specificity of 83.3% to detect anti-T. canis dog sera, respectively. This study presents a comprehensive bioinformatics analysis of the dog roundworm TcUBQ-2, and its strong serodiagnostic performance suggests that rTcUBQ-2 has the potential to be developed into an ELISA-based serological test for detecting toxocariasis in dogs and other accidental hosts, including humans.

Infectious Diseases in the Head and Neck with Eosinophilia

Eosinophilia, defined as an elevated eosinophil count either in blood or tissue, has diverse implications for diagnosing and managing various diseases. Elevated eosinophil levels are often associated with conditions such as allergic reactions, autoimmune disorders, and specific infections. In the realm of head and neck pathology, eosinophilia can offer valuable insights into underlying infectious processes, which are often challenging to diagnose due to their overlap with other inflammatory and allergic conditions. This review describes the roles of blood and tissue eosinophilia in several infectious processes affecting the head and neck region. We focus on nine key conditions: allergic fungal rhinosinusitis, mycetoma, invasive fungal rhinosinusitis, rhinosporidiosis, baylisascariasis, toxocariasis, onchocerciasis, loiasis, and histoplasmosis. Allergic fungal rhinosinusitis, for example, is a hypersensitivity reaction to fungal antigens and is frequently associated with significant eosinophilic inflammation. Conversely, mycetoma, invasive fungal rhinosinusitis, and rhinosporidiosis may include eosinophils as part of a mixed inflammatory infiltrate. Histoplasmosis may also induce systemic eosinophilia as an atypical immune response to fungal infection. Additionally, baylisascariasis, toxocariasis, onchocerciasis, and loiasis are parasitic infections that often lead to systemic eosinophilia. By exploring these conditions, this review elucidates how identification of eosinophilia contributes to the diagnostic process. Understanding the association between eosinophilia and these infectious processes involving the head and neck is crucial for enhancing diagnostic accuracy, differentiating between similarly presenting conditions, and guiding effective treatment strategies.

Toxocara cati Infection in Cats (Felis catus): A Systematic Review and Meta-Analysis

Introduction: Toxocariasis is an infection caused in canines, felines, humans, and other vertebrates by species of the genus Toxocara, such as T. canis and T. cati. The embryonated eggs of these parasites are the primary means of acquiring the infection for both definitive hosts, dogs and cats, respectively, and for intermediates, such as humans and other vertebrates. When deposited on park soils, environmental contamination becomes a risk to environmental, human, and animal health. Objective: To determine the global prevalence of Toxocara cati in cats (Felis catus). Methods: A systematic review of the literature was carried out in six databases (Scopus, PubMed, ScienceDirect, SciELO and Google Scholar) to evaluate the global prevalence of Toxocara cati in cats, defined by coproparasitological, histological, and molecular techniques. A meta-analysis was performed using a random effects model to calculate pooled prevalence and 95% confidence intervals (95% CI). A two-tailed 5% alpha level was used for hypothesis testing. Results: Two hundred and eighty-nine studies were included. The global pooled prevalence of Toxocara cati in cats using coproparasitological methods was 17.0% (95.0% CI: 16.2-17.8%). In the subgroup analysis according to country, Nepal had the highest prevalence of T. cati infection (94.4%; 95% CI 89.7-99.2%). The pooled prevalence of T. cati infection by PCR in four studies was 4.9% (95.0% CI: 1.9-7.9%). Conclusions: This systematic review underscores the need for preventive action against toxocariasis due to its widespread prevalence. The interplay between animal and human health should be emphasised, necessitating measures like deworming cats, hygiene practices, and public education to mitigate risks. Safeguarding feline health can also reduce human transmission, benefiting both species.