Toxocara Canis infestation with encephalitis

SUMMARYThe syndrome “visceral larva migrans” produced by migration of nematode larvae (commonly Toxocara species) in the extraintestinal tissues in unusual hosts, including man (particularly children of dirt eating age), with the production of reactive granulomatous lesions, was first described in 1952. About 200 cases have been reported since. Well documented cases are rare due to the difficulty in histological verification. Three cases have been reported in Canada but these were not verified. We believe the present report is the first verified case of visceral larva migrans in Canada and the fifth case of human cerebral involvement by Toxocara in the English literature. It is hoped that this report will emphasize the need for further research into the role of host versus parasite and will underline the potential danger, albeit remote, of household pets to children. Indeed, prevention is the only line of attack, as there is no effective drug against the migrating larvae of Toxocara.

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CHRONIC EOSINOPHILIA DUE TO VISCERAL LARVA MIGRANS

PEDIATRICS ◽

10.1542/peds.9.1.7 ◽

1952 ◽

Vol 9 (1) ◽

pp. 7-19 ◽

Cited By ~ 2

Author(s):

P. C. BEAVER ◽

C. H. SNYDER ◽

G. M. CARRERA ◽

J. H. DENT ◽

J. W. LAFFERTY

Keyword(s):

Infected Individual ◽

Toxocara Canis ◽

Benign Disease ◽

Larva Migrans ◽

Toxocara Cati ◽

Visceral Larva Migrans ◽

Nematode Parasites ◽

Granulomatous Lesions ◽

Tissue Reactions ◽

Migration And Development

Three cases of chronic extreme eosinophilia with granulomatous lesions in the liver have been studied. A larval nematode observed in sections from the liver of one patient has been identified either as Toxocara canis or Toxocara cati, common cosmopolitan ascarids of dogs and cats; available evidence favors the former. The term visceral larva migrans is proposed for this type of parasitism, known in animals but not previously described in humans. It is related to better known cutaneous larva migrans, in that both are usually caused by infective stage larvae of nematode parasites of other animals. Man being an abnormal host, either has unfavorable tissue reactions or otherwise fails to provide stimuli for usual tissue migration and development of the parasite. As a result, larvae remain active for variable periods in various tissues. Similar but less severe and less prolonged reactions occur when the larvae of normal nematode parasites of man invade the tissues of a hyperimmune individual. Visceral larva migrans is usually a relatively benign disease, characterized chiefly by sustained eosinophilia, pneumonitis and hepatomegaly, and probably is due both to direct tissue damage by migrating larvae and to allergic responses to their products. Its severity varies with the number of larvae in the tissues and the immune or allergic state of the infected individual.

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Cross-reactivity between Anisakis simplex sensitization and visceral larva migrans by Toxocara canis

Acta Tropica ◽

10.1016/s0001-706x(03)00201-8 ◽

2003 ◽

Vol 89 (1) ◽

pp. 85-89 ◽

Cited By ~ 19

Author(s):

M.J. Perteguer ◽

C. Cuéllar ◽

J.L. Guillén ◽

C. Águila ◽

S. Fenoy ◽

...

Keyword(s):

Toxocara Canis ◽

Cross Reactivity ◽

Anisakis Simplex ◽

Larva Migrans ◽

Visceral Larva Migrans

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Visceral larva migrans detection using PCR–RFLP in BALB/c mice infected with Toxocara canis

Journal of Helminthology ◽

10.1017/s0022149x19000609 ◽

2019 ◽

Vol 94 ◽

Author(s):

G. Özbakış ◽

A. Doğanay

Keyword(s):

Toxocara Canis ◽

Development Stage ◽

Clinical Syndrome ◽

Larva Migrans ◽

Pcr Analysis ◽

Visceral Larva Migrans ◽

Molecular Method ◽

Affected Tissue ◽

Test Specificity ◽

Paratenic Hosts

Abstract Toxocara canis is an important zoonotic roundworm distributed worldwide. The infective larvae of T. canis are one of the causes of visceral larva migrans (VLM), a clinical syndrome in humans. Diagnosing VLM is difficult, and the differential diagnosis of the larval development stage is limited. Therefore, this experimental research aimed to diagnose T. canis larvae using a molecular method, not only in liver tissue, which is the most commonly affected tissue, but also in the limb muscles, lungs and brain tissues. For this purpose, 24 BALB/c mice were infected with 1000 embryonated T. canis eggs. Necropsies were performed on the second, fourth, seventh and 14th days post-infection. While a part of the samples were digested with pepsin-HCl, the molecular method was used for the remainder of the samples to replicate the mitochondrial DNA adenosine triphosphate (ATP) synthase subunit-6 gene region of T. canis. BbsI, a restriction endonuclease, was used to determine the specificity of the amplicons obtained from Polymerase chain reaction (PCR). The detection limit for embryonated eggs was recorded. The PCR results showed that the sensitivity of the PCR analysis was 83.3% in the liver (with 88.8% accuracy), 87.5% in the lungs (with 91.6% accuracy) and 75.0% in the brain, forelimb and hindlimb muscles (with 83.3% accuracy). In all tissues, the test specificity was determined to be 100%. In this study, the molecular method was applied to only experimentally infected BALB/c mice tissues; thus, it is suggested that it can be also employed in different paratenic hosts and materials possibly infected with T. canis.

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Ocular lesions in gerbils (Meriones unguiculatus) infected with low larval burden of Toxocara canis: observations using indirect binocular ophthalmoscopy

Revista da Sociedade Brasileira de Medicina Tropical ◽

10.1590/s0037-86822008000600005 ◽

2008 ◽

Vol 41 (6) ◽

pp. 570-574 ◽

Cited By ~ 5

Author(s):

Ledilma Inês Duarte Colodetti Zanandréa ◽

Gabriela Mantovanelli Oliveira ◽

Andressa Silva Abreu ◽

Fausto Edmundo Lima Pereira

Keyword(s):

Retinal Detachment ◽

Histological Examination ◽

Inflammatory Reaction ◽

Toxocara Canis ◽

Meriones Unguiculatus ◽

Larva Migrans ◽

Ocular Lesions ◽

Ocular Larva Migrans ◽

Granulomatous Lesions ◽

Larval Burden

To study the frequency of ocular lesions in 30 gerbils infected with 100 embryonated eggs of Toxocara canis, indirect binocular ophthalmoscopy was performed 3, 10, 17, 24, 31 and 38 days after infection. All the animals presented larvae in the tissues and 80% presented ocular lesions. Hemorrhagic foci in the choroid and retina were present in 92% of the animals with ocular lesions. Retinal exudative lesions, vitreous lesions, vasculitis and retinal detachment were less frequent. Mobile larvae or larval tracks were observed in four (13.3%) animals. Histological examination confirmed the ophthalmoscopic observations, showing that the lesions were focal and sparse. In one animal, there was a larva in the retina, without inflammatory reaction around it. The results demonstrated that gerbils presented frequent ocular lesions after infection with Toxocara canis, even when infected with a small number of embryonated eggs. The lesions observed were focal, consisting mainly of hemorrhages with signs of reabsorption or inflammation in different segments of eye, and differing from the granulomatous lesions described in ocular larva migrans in humans.

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Presence of Toxocara canis eggs on the hair of dogs: A risk factor for Visceral Larva Migrans

Veterinary Parasitology ◽

10.1016/j.vetpar.2010.07.016 ◽

2010 ◽

Vol 174 (1-2) ◽

pp. 115-118 ◽

Cited By ~ 31

Author(s):

Hugo Leonardo da Cunha Amaral ◽

Gabriela Lopes Rassier ◽

Michele Soares Pepe ◽

Tiago Gallina ◽

Marcos Marreiro Villela ◽

...

Keyword(s):

Risk Factor ◽

Toxocara Canis ◽

Larva Migrans ◽

Visceral Larva Migrans

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Hepatic visceral larva migrans due to Toxocara Canis

Gastroentérologie Clinique et Biologique ◽

10.1016/j.gcb.2010.07.012 ◽

2010 ◽

Vol 34 (11) ◽

pp. 573-574 ◽

Cited By ~ 1

Author(s):

S.H. Chandrashekhara ◽

R. Sharma ◽

S. Bagh ◽

P. Garg

Keyword(s):

Toxocara Canis ◽

Larva Migrans ◽

Visceral Larva Migrans

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Precipitin reactions in monkeys (Macaca sinica) experimentally infected with Toxocara canis and in children with visceral larva migrans syndrome

Journal of Comparative Pathology ◽

10.1016/0021-9975(70)90071-x ◽

1970 ◽

Vol 80 (3) ◽

pp. 407-IN12 ◽

Cited By ~ 5

Author(s):

S.T. Fernando ◽

B. Vasudevan ◽

M.H.M. Hamza ◽

I.K.T. Panditha-Gunawardene ◽

H.T. Samarasinghe

Keyword(s):

Toxocara Canis ◽

Larva Migrans ◽

Visceral Larva Migrans ◽

Macaca Sinica ◽

Visceral Larva Migrans Syndrome

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VISCERAL LARVA MIGRANS

PEDIATRICS ◽

10.1542/peds.28.1.85 ◽

1961 ◽

Vol 28 (1) ◽

pp. 85-91

Author(s):

C. Harrison Snyder

Keyword(s):

Clinical Features ◽

Toxocara Canis ◽

Infected Tissue ◽

Larva Migrans ◽

Visceral Larva Migrans ◽

Small Children ◽

Eye Enucleation ◽

The Past

An analysis has been presented of the clinical features of visceral larva migrans based on the study of 20 cases seen during a 10-year period at the Ochsner Clinic. The disease is seen in small children who eat dirt and who thus ingest the ova of the canine roundworm, Toxocara canis. Larvae of the parasite invade the liver, causing hepatomegaly with extreme eosinophilia, and usually fever and anemia. Migration of the larvae to other organs may result in pneumonitis, encephalitis or myocarditis. Lesions may also be seen in skin, kidneys and possibly in bone. Proof of diagnosis requires biopsy of liver or other infected tissue. Treatment with diethylcarbamazine (Hetrazan) may be helpful, but even without treatment, once pica is stopped most patients recover. Serious sequelae are seen in the form of intraocular granulomata, sometimes causing blindness. These lesions, because they resemble retinoblastoma, have in the past led to unnecessary enucleation of the eye. Enucleation for suspected retinoblastoma, therefore, should not be performed without due consideration of the possibility of a benign granuloma caused by T. canis.

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