Who Let the Dogs Out? Unmasking the Neglected: A Semi-Systematic Review on the Enduring Impact of Toxocariasis, a Prevalent Zoonotic Infection

Abstract

Toxocariasis remains an important neglected parasitic infection representing one of the most common zoonotic infections caused by the parasite Toxocara canis or, less frequently, by Toxocara cati. The epidemiology of the disease is complex due to its transmission route by accidental ingestion of embryonated Toxocara eggs or larvae from tissues from domestic or wild paratenic hosts. Even though the World Health Organization and Centers for Disease Control classified toxocariasis amongst the top six parasitic infections of priority to public health, global epidemiological data regarding the relationship between seropositivity and toxocariasis is limited. Although the vast majority of the infected individuals remain asymptomatic or experience a mild disease, the infection is associated with important health and socioeconomic consequences, particularly in underprivileged, tropical, and subtropical areas. Toxocariasis is a disease with multiple clinical presentations, which are classified into five distinct forms: the classical visceral larva migrans, ocular toxocariasis, common toxocariasis, covert toxocariasis, and cerebral toxocariasis or neurotoxocariasis. Anthelmintic agents, for example, albendazole or mebendazole, are the recommended treatment, whereas a combination with topical or systemic corticosteroids for specific forms is suggested. Prevention strategies include educational programs, behavioral and hygienic changes, enhancement of the role of veterinarians, and anthelmintic regimens to control active infections.

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

“…This systematic review and meta-analysis, aimed at determining the pooled prevalence of Toxocara cati in cat populations worldwide using a comprehensive search approach across six databases, found a relevant prevalence. The findings underscore the considerable diversity in parasite prevalence across various countries and continents, as indicated by previous studies [20,313,314]. Through an extensive exploration of studies published between 1973 and 2023 across diverse geographic regions, this study facilitated the execution of a meta-analysis to ascertain the global prevalence of T. cati.…”

Comprehensive control of toxocariasis in communities

“…Today, even though there are indicators of approximately 1.4 billion people exposed or infected by Toxocara spp., toxocariasis remains an underdiagnosed parasitic disease [22], with underestimated epidemiological rates, as well as the real impact of this pathology on global public health [12,14,23]. Because the diagnosis of this parasitic infection in humans is subject to serological examination that detects antibodies against Toxocara excretory-secretory (TES) antigens.…”

“…Remembering "The Iceberg Model" within the diagnosis of a problematic situation in public health, where only the tip of the iceberg (the observable cases of direct correspondence to the infectious agent) correspond to 10% of the true magnitude of the problem [9], we can understand the real importance of toxocariasis. Toxocara is associated with alterations in the immune system's response to vaccines for various preventable infectious and contagious pathologies (e.g., rabies), in addition to a series of autoimmune diseases [10][11][12][13][14]. Additional studies indicate that CT may represent a major cause of lung dysfunction, cognitive disturbances, and intellectual deficits in children living in poverty [15].…”