Prevalence and molecular characterization of zoonotic helminths in dogs

Epidemiological survey on intestinal helminths of stray dogs in Guimarães, Portugal

The new legislative framework on Animal Welfare brought increased responsibilities to municipal shelters, in particular in the collection of stray dogs, their sterilization and future adoption. These centers quickly became overcrowded, leading to high parasitism environmental contamination, to the easy spread of parasitic infections and to increased risks to public health. The prevalence of intestinal parasites was evaluated by examination of dog faecal sample, in the municipal control animal centre of Guimarães (north Portugal), identifying risk factors and transmission to man. The overall prevalence of gastrointestinal helminths was 57.2% (95% confidence interval 41.3–71.9%) and observed helminths of the gastrointestinal tract were recorded: Ancylostoma caninum (33%), Toxocara canis (29%), Dipylidium caninum (6%), Capillaria spp. (3%), Trichuris vulpis (1.66%). It is important to point out that young dogs were significantly infected more frequently (p ≤ 0.1) than non-sterilized females and the higher occurrence of nematode infection occurred at the new arrival of stray dogs, in the third collection. With impact on public health, the higher prevalence (p ≤ 0.1) of T. canis in young dogs suggests the existence of real risk for human infection and demonstrate the necessity for a parasite control programme reinforcement at the municipal dog shelter.

Canine Toxocariosis: Its prevalence, incidence and occurrence in the Indian subcontinent

Toxocariosis is an important neglected tropical helminth disease of zoonotic significance for which canids are the definitive hosts. Dogs are also considered the sentinel host for the occurrence of T. canis infections in humans. Therefore, understanding its prevalence in canine population is imperative for any effective disease control in humans. A comprehensive review of literature on the prevalence of T. canis in canids was lacking from the Indian subcontinent which necessitated our efforts to compile available data published on this topic. Data on prevalence, incidence and occurrence of this helminths in canids were presented in this review as tabular format for easy comprehension. Moreover, the data were categorized based on the region where the studies were conducted with an aim to understand the spatial distribution of this parasite in the subcontinent. Factors influencing the regional prevalence/occurrence of T. canis such as type of canids (stray or pet), age, sex, breed, season and the choice of analytical methods were also discussed. In addition, data on the prevalence of T. canis in environmental samples and in zoo canids were also compiled and presented. We anticipate such an exhaustive review of literature available mostly in the journals published from the subcontinent would become a point source of information necessary for prioritizing future surveillance efforts in this region and for making informed policy decision to control this zoonotic helminth infection.

Human toxocariasis - A look at a neglected disease through an epidemiological 'prism'

Toxocariasis, a disease caused by infection with larvae of Toxocara canis, T. cati and/or congeners, represents clinical syndromes in humans including visceral and ocular larva migrans, neurotoxocariasis and covert/common toxocariasis. It is reported to be one of the most widespread public health and economically important zoonotic parasitic infections that humans share with dogs, wild canids, including foxes, and possibly other mammals. Humans become infected by accidental ingestion of embryonated Toxocara eggs, or larvae from tissues from domestic or wild paratenic hosts. Most infections are asymptomatic, and human disease may go unnoticed, as clinical investigation is often not pursued and/or diagnostic testing not conducted. Sometimes toxocariasis can be associated with complications, such as allergic and/or neurological disorders, possibly including cognitive or developmental delays in children. There is no anti-toxocariasis vaccine, and chemotherapy in humans varies, depending on symptoms and location of larvae, and may include the administration of albendazole or mebendazole, together with anti-inflammatory corticosteroids. Some recent studies indicate that toxocariasis is having an increased, adverse impact on human health in some, particularly underprivileged, tropical and subtropical communities around the world. Although tens of millions of people, especially children, are expected to be exposed to, or infected with Toxocara species, there is limited precise epidemiological data or information on the relationship between seropositivity and disease (toxocariasis) on a global scale. To gain an improved insight into this area, the present article reviews salient clinical aspects of human toxocariasis and the epidemiology of this disease, with particular reference to seroprevalence, and discusses future research and approaches/measures to understand and prevent/control this socioeconomically important, yet neglected zoonosis.