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The Parasite's Way of Life
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
Vertical transmission refers to the transmission of parasites from mother to offspring, either across the placenta or through breast milk in the case of mammals or via infected gametes. Toxocara canis, for example, is a common nematode parasite of dogs. Puppies are frequently infected before birth as a consequence of transplacental transmission. Earlier in this chapter, we mentioned that Alaria americana can be transmitted through breast milk.
Diseases of the Hepatobiliary Tree and Pancreas Associated with Fever
Published in Benedict Isaac, Serge Kernbaum, Michael Burke, Unexplained Fever, 2019
Toxocariasis217,218 — The ingestion of larvae of Toxocara canis leads to their penetration of the intestinal wall and entrance into the bloodstream where they reach the liver, lung and other tissues. The infection is often asymptomatic, but may be expressed clinically in the form of visceral larva migrans, which is characterized by fever, tender hepatomegaly, splenomegaly, pneumonitis and a skin rash. Eosinophilia and hypergammaglobulinemia are frequently observed. Liver biopsy may reveal eosinophilic granuloma and larvae of Toxocara.
Toxocara
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
The genus Toxocara covers a large group of parasitic nematodes of carnivores with a relatively complex life cycle even though an intermediate host is not involved (see Figure 82.2, and Section 82.3 for details). As accidental host, humans are susceptible to Toxocara infection (toxocariasis, especially Toxocara canis [commonly known as dog roundworm] and Toxocara cati [cat roundworm]) upon ingestion of raw vegetables or meat containing embryonated eggs or larvae, leading to visceral larva migrans (VLM) and other forms of toxocariasis.
Diffuse Unilateral Subacute Neuroretinitis Evolving With Submacular Granuloma
Published in Ocular Immunology and Inflammation, 2021
Thiago José Muniz Machado Mazzeo, Nelson Batista Sena, Mario Martins Motta, André Luiz Land Curi
A 16 years old, healthy, male patient presented with unilateral progressive visual impairment in oculus sinister (OS) that initiated 4 months ago. There is no history of previous trauma or ocular disease. Distance corrected visual acuity (DCVA) was 20/20 on oculus dexter (+0.50 − 0.25 x 170) and 20/100 OS (+0.75 − 0.25 x 180). He had a normal anterior segment examination on slit-lamp biomicroscopy and intraocular pressure by Goldmann’s applanation tonometer was 15/15 mmHg. OS fundus examination revealed optic disc hyperemia and a retinochoroidal yellowish lesion in macular region, suggestive of granuloma, associated with mild vitritis (Figure 1a). The autofluorescence examination showed a circular hypoautofluorescence in the lesion area (Figure 1b). The posterior segment examination of OD was completely normal. Optical Coherence Tomography (OCT) of OS (Figure 2a), showed an elevation of the neurosensorial retina with an underlying hyperreflective lesion associated with subretinal fluid. The patient had no peripheric eosinophilia and Enzyme-Linked Immunosorbent Assay (ELISA) for Toxocara canis was negative.
Clinical Features of Toxocara-Seropositive Optic Neuritis in Korea
Published in Ocular Immunology and Inflammation, 2019
Hyeshin Jeon, Young Hwan Jeong, Hee-young Choi, Ji Eun Lee, Iksoo Byon, Sung Who Park
Toxocariasis is a helminthic zoonosis caused by infection with Toxocara canis or T. cati. Ocular toxocariasis classically presents with retinal granuloma or nematode endophthalmitis.6 However, it has been reported that the nematode can also invade the ciliary body,7 lens,8 optic nerve,9 or sclera.10 In the absence of typical manifestations of ocular toxocariasis, toxocara optic neuropathy may be misdiagnosed as idiopathic optic neuritis, and the incidence may therefore be underestimated. A remarkable number of Toxocara-related optic neuropathy cases have been reported from Korea9,11,12; therefore, we suspected that Korean optic neuritis patients with atypical features may be infected with Toxocara.
Clinical Profile, Treatment, and Visual Outcome of Ocular Toxocara in a Tertiary Eye Care Centre
Published in Ocular Immunology and Inflammation, 2018
Ekta S. Sahu, Bikramjit Pal, Tarun Sharma, Jyotirmay Biswas
Toxocara represents one of the well-recognized helminthic zoonosis in human caused by the larva of dog nematode Toxocara canis or less frequently by the cat nematode Toxocara cati. The natural hosts are dogs or cats, and human transmission is through accidental ingestion of contaminated food or geophagia and contact with infected puppies. Toxocara larva migrate into the posterior segment through blood vessels in the circulatory system and incite immune reaction, resulting in a wide spectrum of presentation.1,2 The first reported cases were in children in 1950.3 Ocular toxocariasis is considered a disease of young children but recent reports from Japanese and Korean populations4,5 have highlighted a high prevalence of ocular toxocariasis in east Asian’s adult males.6–8 The disease is usually diagnosed clinically by characteristic ocular manifestations and is confirmed serologically. However, the diagnosis of ocular toxocariasis remains presumptive and the treatment approach using corticosteroids and anthelmintics is unclear. To the best of our knowledge, there is no detailed epidemiologic study to determine the extent of the disease and little is known about the epidemiologic, demographic, and clinical features of ocular toxocariasis among the Indian population. To gain a better understanding of presentation of the disease and visual outcome, we reviewed the database of diagnosed ocular toxocariasis patients at our center, by a chart review.