Toxocariasis ocular. A propósito de un caso / Ocular toxocariasis. Case report

RESUMEN Se presentó un caso clínico de un paciente de seis años de edad, con toxocariasis ocular. La manifestación clínica fue disminución de la agudeza visual monocular. El fondo de ojo izquierdo mostró un granuloma retiniano periférico, asociado a un desgarro retiniano perilesional. El examen oftalmológico confirmó el diagnóstico de Toxocara ocular. El paciente fue tratado posteriormente mediante corticoides sistémicos y fotocoagulación láser focal en el desgarro retiniano (AU).

ABSTRACT We present the clinical case of a male patient, aged 6 years, with ocular toxocariasis. The clinical manifestation was monocular visual acuity decrease. The left ocular fundus showed a peripheral retina granuloma, associated to a perilesional retinal tear. The ophthalmological examination confirmed the diagnosis of ocular Toxocara. After that the patient was treated using systemic corticoids and focal laser coagulation in the retinal tear (AU).

Epidemiological aspects and risk factors of toxocariasis in a pediatric population in Sri Lanka.

This cross-sectional study, carried out over a period of 11 months, investigated the relationship between Toxocara seropositivity, socio-demographic and environmental variables in a pediatric population. Risk factors for Toxocara infection were assessed by direct interview of parent or guardian using a structured pre-tested questionnaire. Eosinophilia and presence of helminth eggs or protozoan cysts in a fecal smear were recorded. Diagnosis of Toxocara seropositivity in children was based on IgG Toxocara Microwell Serum Elisa Kits. The ELISA test was regarded as positive if the optical density was 0.3 units or above. Unadjusted and adjusted odds ratios were calculated to determine risk factors for disease. The proportion of children who were positive for Toxocara antibodies in the study population was 20%. Children being exposed to a puppy of less than 3 months at home, visiting a playground frequently, living in a poorly constructed house and dogs having access to playgrounds were significant risk factors on univariate analysis. Of these four variables, only the first three variables (OR 19, OR 4 and OR 3, respectively) remained significant risk factors on the multivariate model. Presence of eosinophilia in seropositive children was significantly higher than the seronegative group (77% vs 40%; p < 0.001). This study indicates that dogs contribute significantly to children being seropositive for toxocariasis in Sri Lanka. Implementation of public health programs specifically focused on anti-parasitic treatment of dogs is recommended.

Manifestation of toxocariasis in children with neuroblastoma treated with autologous hematopoietic transplants.

Toxocariasis was diagnosed in 3 out of 22 children (14%) treated in our center with high-dose chemotherapy and autologous hematopoietic stem cell transplantation (HSCT). The patients were coming from rural areas in the southeastern Poland and did not present any clinical symptoms of toxocariasis upon admission to the hospital. Although no neurological and ophthalmological abnormalities were noticed, the atypical form of toxacariasis was diagnosed based on elevated eosinophils counts, positive serological tests, and biochemical symptoms of liver damage. The authors conclude that toxocariasis should be taken into consideration in the differential diagnosis of eosinophilia in children undergoing high-dose chemotherapy and HSCT, especially if they are coming from rural areas.

Animal models in ocular toxocariasis.

Ocular toxocariasis is a clearly defined disease. However, much remains to be learned concerning the migratory route, ocular changes, diagnosis and treatment. Studies in paratenic hosts have contributed to our understanding and will yield more information. Various experimental animals have been used, such as mice, rabbits, guinea pigs, primates, hamsters and gerbils. Of these, the last appear to be the most appropriate model due to their high susceptibility to ocular infection. Results obtained from different animal models are often not comparable due to the fact that dose and routes of inoculation are diverse. Early stages in the pathogenesis of ocular toxocariasis are manifested by haemorrhages in the anterior chamber and iris, replaced in time by accumulations of white cells. Ocular migration produces an early cell reaction, formed by an infiltration of neutrophils accompanied by vasculitis and retinal microinfarcts. Over a period of time, an increase of macrophages and the distribution of the infiltrates is observed. Later, granulomatous lesions are formed. These do not necessarily contain a larva and their appearance varies in different animal models. Local production of IgE and the presence of specific IgG have been described.

Larva migrante visceral (toxocariasis humana) causa de hipereosinofilia y granulomas viscerales en el adulto / Visceral larva migrans (human toxocariasis) cause of hypereosinophilia and visceral granulomas in the adults

A 24-year -old woman 2-3 months after a normal parturation presented geophagy. Due to hypermenorrhea she consulted a gynecologist and in a hemogram a 57 percent (6, 893 x mm3) hypereosinophilia was detected. A chest TAC showed bilateral pulmonary nodules. The following tests resulted positive: ELISA IgG for toxocariasis 1: 1000, isohemagglutinins anti A 1:2048 and anti B 1:512. The patient was treated with albendazole and prednisone during 10 days. One month after treatment eosinophilia decreased to 2.590 x mm3 and ELISA IgG for toxocariasis descended to 1:128. Different aspect of human toxocariasis are commented. When hypereosinophia is observed in adult patients, toxocariasis must be checked

Frecuencia de hallazgo de huevos de toxocara cati en gatos domésticos de Ciudad de México y del estado de México / Frequency of toxocara cati eggs in domestic cats at Mexico City and at Mexico State

Toxocariosis is a zoonosis which has beem widely studied in dogs. However, not much is known about this parasitosis in cats. The aim of the present work was to determine the frequency of Toxocara cati in domestic cats in Mexico City and the State of Mexico. Feces of 660 domestic cats were studied by the Faust concentration-floating test; 401 samples were from cats living in Mexico City of which 308 lived in houses and 93 in apartments; 231 were from urban areas of the State of Mexico an 28 from a rural area of the same state. The total frequency of T. cati eggs obtained from domestic cats in Mexico City was 42.9 percent; in cats living in apartments it was 18.3 percent and in cats living in houses it was 50.3 percent. In domestic cats from the State of Mexico, T. cati frequency was 36.4 percent in the urban and 21.4 percent in the rural areas. We consider that toxocariosis frequency observed at the two studied sites is high and that the need to prevent dissemination of the infectious forms of T. cati is urgent,as it the necessity of informing the population of the risk of living with T. cati parasited animals and of the anatomopathological alterations caused by T. cati in man

Human toxocariasis and the visceral larva migrans syndrome: correlative immunopathology.

The surface of T. canis is now recognized as a dynamic structure which turns over quite rapidly and serves as a renewable source of large quantities of antigen(s). The major host responses to these antigens include a marked eosinophilia and hyperglobulinemia. Both of these responses are apparently ineffective at ridding the body of infective larvae. Both eosinphils and IgE antibodies are manifestations of the Th2 subset of T helper cells and the cytokines that they secrete. Further, there is reason to believe that the antigens released from T. canis larvae favor the induction of this cellular population. Finally, there is mounting evidence that the chronic production of parasite antigen and its continued stimulation of the host immune system with a concomitant production of eosinophils can lead to a permanent alteration of the normal organization of the cardiopulmonary system. In the absence of any well-documented drugs capable of killing infective larvae, it would seem that immunological intervention may offer the only way to minimize or neutralize this 'gift from man's best friend'. This chapter was not intended to be an exhaustive review of the literature pertaining to toxocariasis. Several other recent publications will hopefully fulfill the need for more detailed information on the biology of this organism and the clinical spectrum of the disease it produces [16, 138-140]. Finally, a MEDLARS search of the current medical literature should bring anyone up to speed in a very short time.

Diagnostic vitrectomy and chronic uveitis.

BACKGROUND: From the introduction of vitrectomy, infectious endophthalmitis was one of the indications for this surgical technique. Vitrectomy was later found to be a valuable method in both diagnostic and therapeutic evaluation of chronic uveitis. METHODS: Twenty-eight eyes of 25 patients were operated on with purely diagnostic intent. These were patients not responding, or no longer responding, to their cortisone treatment and for whom no etiology had been found previously. RESULTS: Vitrectomy itself yielded the diagnosis in nine eyes of eight patients. Three had unexpected infectious pathology (one bacterial, one mycotic, one viral), while five had tumoral pathology four with non-Hodgkin lymphoma and one with a metastasis of a malignant melanoma of the skin. In four other patients, typical fundus lesions were seen during the surgery, providing a clue to the etiology: three cases of retinal necrosis and one case of a pseudotumoral mass suggestive of Toxocara canis. Serologic tests confirmed three cases of herpes simplex infection and one of Toxocara canis. Apart from the fact that a diagnosis could be made in half of the patients, the diagnostic vitrectomy also had a favorable effect upon vision in half the cases. CONCLUSION: In cases of chronic uveitis where no etiology has been found, vitrectomy is able to provide a diagnosis in about one-third of eyes directly. During surgery a typical appearance of the fundus may reveal a supplementary diagnosis, resulting in an overall diagnosis in about half of the cases. Moreover, half of the patients will have improved vision after surgery.

Afectación ocular en la toxocariasis / Eye infection in the toxocariasis

La toxocariasis es una infección por un nematodo que tiene dos formas clínicas de manifestarse: larva migrans visceral y toxocariasis ocular. estas últimas es casi exclusivamente unilateral y típica de la edad infantil; sin embargo, se ha descrito en individuos desde los 2 a los 40 años de edad. Puede presentarse con disminución de la visión, estrabismo, leucocoria o uveítis. Más frecuente es la presencia de un granuloma subrretiano en el polo posterior, o bien un granuloma coriorretiniano periférico. Menos frecuente es la existencia de una endoftalmitis con desprendimiento de retina. Las tres formas de afección ocular presentan las mismas patogenia. Presentamos dos casos clínicos correspondientes a un granuloma coriorretiniano periférico en un varón de 42 años de edad, y a un granuloma de polo posterior en un varón de 29 años. En ambos pacientes el diagnóstico se realizó fundamentalmente por los signos y síntomas, el aspecto clínico típico del fondo de ojo y los antecedentes personales

Diffuse unilateral subacute neuroretinitis. Report of transvitreal surgical removal of a subretinal nematode.

BACKGROUND: The precise identification of nematodes which cause diffuse unilateral subacute neuroretinitis (DUSN) has been unsuccessful. Shape and size are useful in the initial stages of identification, but histopathologic examination usually is necessary for accurate classification. Intact nematodes recovered from patients with DUSN have been mentioned scarcely in the literature. The authors report the first case of DUSN in which a viable nematode was removed successfully via a transvitreal surgical approach and recovered for parasitologic study. METHODS: Bimanual pars plana vitrectomy was performed in a 9-year-old Brazilian boy with typical DUSN in its late stage. During surgery, a motile subretinal nematode was confirmed temporal to the macular area. A retinotomy was created adjacent to the nematode. The subretinal material then was aspirated with a 20-gauge soft-tip needle, and parasitologic examination was performed. RESULTS: Based on length (630 m x 10(-6)) and width (30 m x 10(-6)) of the nematode and other features such as a small buccal capsule, an esophagus one third of body length, and tapered tail, a morphologic identification of the nematode was made as a third-stage Toxocara larva. Histopathologic examination could not be performed for confirmation because of subsequent deterioration of the specimen. CONCLUSIONS: Although direct laser photocoagulation of the nematode is the treatment of choice for DUSN, surgical transvitreal removal of the nematode may be indicated in selected cases. This method for treatment allows removal of the nematode for parasitologic identification.

Toxocariasis: un caso clínico de larva migrans visceral / Toxocariasis: a clinical case of visceral larva migrans

Se presenta un caso de toxocariasis diagnosticado en una paciente de 18 años hospitalizada por un cuadro clínico de comienzo brusco caracterizado por disnea, dolor torácico, pérdida del conocimiento con relajación de esfínteres y hepatomegalia dolorosa. El estudio realizado demostró una moderada leucocitosis con eosinofilia de 24 a 55% y reacción de toxocariasis positiva 1/64. La enferma fue tratada con tiobendazol observando una rápida mejoría subjetiva con desaparición de la sintomatología respiratoria, digestiva y neurológica y con gradual reducción de la eosinofilia y del título de la reacción de toxocariasis

Toxocariasis en la poblacion asintomatica / Toxocariasis in the asymptomatic population

En esta comunicacion se pretende condensar los datos mas importantes del protocolo de trabajo sobre el tema de la toxocariasis ocular en Bogota, asi como dar a conocer los resultados de esta investigacion, cuyos propositos han sido contribuir al desarrollo del laboratorio diagnostico de parasitosis a traves de la estandarizacion de la tecnica ELISA para Toxocara canis, y alertar acerca de la presencia de la parasitosis canina en humanos, con el impacto de esta sobre la morbilidad ocular y la incapacidad permanente por ceguera, teniendo en cuenta la intratabilidad de la lesion una vez declarada