Toxocara canis 30-35 kDa excretory-secretory antigen is an important marker in mice challenged by inocula containing different parasite load levels

ABSTRACT The Western-blotting technique was applied to identify antigenic fractions of excretory-secretory Toxocara canis antigen recognized by IgG antibodies throughout an experimental infection in mice challenged by different inocula. Mice were inoculated with 5, 50 and 500 embryonated eggs and serum samples were collected 15, 30, 60, 90 and 120 days post-infection. Serum samples were analyzed using an excretory-secretory Toxocara antigen. Antibodies recognized antigenic fractions from 30 to 90 kDa. The protein fraction of 30-35 kDa was the most frequently recognized regardless of the size of inoculum and the stage of infection represented by the different collection times, but the antigenic recognition was more evident in groups infected with 50 and 500 eggs. This study presents an antigenic panel of the excretory-secretory antigen of T. canis and suggests that the 30-35 kDa antigenic fraction is a promising marker of the infection and should be further explored in future studies on experimental toxocariasis.

Toxocariasis en niños: análisis de 85 casos en un hospital pediátrico de Argentina / Toxocariasis in children: analysis of 85 cases in a paediatric hospital in Argentina

INTRODUCCIÓN: La toxocariasis es una enfermedad parasitaria ampliamente distribuida. Las formas clínicas descritas son la asintomática (TA), larva migrans visceral (LMV), larva migrans ocular (LMO) y encubierta (TE). OBJETIVOS: Describir las características clínicas, de laboratorio, evolución y tratamiento de los casos y comparar las diversas formas clínicas de presentación. PACIENTES Y MÉTODOS: Análisis retrospectivo de todos los pacientes pediátricos con diagnóstico de toxocariasis atendidos en el Servicio de Infectología del Hospital General de Niños Pedro de Elizalde entre 2012 y 2019. RESULTADOS: Se incluyeron 85 pacientes. El 63,5 % fueron varones y la mediana de edad fue de 60 meses. Cuarenta y nueve pacientes presentaron TA, 14 LMV, 15 LMO y 7 TE. Los pacientes con LMV presentaron menor edad y recuento de eosinófilos más altos. Todos los casos de LMO presentaron mal pronóstico visual. Se indicó tratamiento con albendazol en todos los casos de LMV, en los casos activos de LMO, en 4 TE y en 3 TA. CONCLUSIÓN: Este estudio representa uno de los más grandes llevados a cabo en el país. Todas las formas clínicas excepto las LMO tuvieron buena evolución. Resulta fundamental enfatizar en la prevención y en el diagnóstico precoz de la enfermedad para instaurar de manera oportuna el tratamiento y evitar secuelas.

BACKGROUND: Toxocariasis is a widely spread parasitic disease. The most frequent clinical form is asymptomatic (AT) although it may present with visceral larva migrans (VLM), ocular larva migrans (OLM) or covert (TE) involvement. Aims: To describe the clinical presentation, laboratory, evolution and treatment characteristics of the cases and to compare the various clinical forms of presentation. PATIENTS AND METHODS: Retrospective analysis of all children diagnosed with toxocariasis attended at the Infectology Service of the Pedro de Elizalde Children's General Hospital between 2012-2019. RESULTS: We included 85 patients. 63.5% were males and the median age was 60 months. 49 patients presented AT, 14 VLM, 15 OLM and 7 TE. Children with LMV had lower age and higher eosinophil count. All the cases of OLM evolved with a poor visual prognosis. Treatment with albendazole was indicated in all cases of LMV, in active cases of LMO, in 4 TE and in 3 AT. CONCLUSION: This study represents one of the largest conducted in our country. The ocular forms had bad prognosis, while the visceral and covert forms had good evolution. It is essential to emphasize the prevention and early diagnosis of the disease in order to establish timely treatment and avoid sequelae.

Factores asociados con la presencia de endoparásitos y ectoparásitos en perros domiciliados de la zona metropolitana de Toluca, México / Factors associated with endoparasites and ectoparasites in domiciled dogs in the metropolitan area of Toluca, México

Resumen | Introducción. Los endoparásitos y ectoparásitos en perros son de distribución mundial. La estrecha relación entre los perros y el hombre implica un riesgo de transmisión de parasitosis zoonóticas, por lo cual es necesario conocer las especies que parasitan a los perros de esta zona y determinar los factores asociados. Objetivos. Estimar la prevalencia de endoparásitos y ectoparásitos, identificarlos en perros domiciliados de la zona metropolitana de Toluca, México, y determinar la prevalencia de Dipyilidium caninum en pulgas del género Ctenocephalides spp. Materiales y métodos. Se recolectaron muestras de 402 perros que fueron llevados a consulta en cuatro hospitales de referencia de Toluca. En el diagnóstico de endoparásitos, se utilizaron las técnicas coproparasitoscópicas de frotis directo, flotación y sedimentación; además, se recolectaron ectoparásitos para su identificación taxonómica. Por último, la detección de D. caninum en pulgas se hizo mediante la reacción en cadena de la polimerasa (PCR). Resultados. El 37,2 % de los perros resultó positivo para endoparásitos. Los géneros o especies identificados fueron Toxocara spp., Giardia spp., Ancylostoma spp., Cystoisospora spp., D. caninum, Taenia spp. y Trichuris vulpis. Se determinó una prevalencia de ectoparásitos de 13,13 %. Se identificaron pulgas de las especies Ctenocephalides felis y C. canis, en tanto que solo un animal presentó parasitosis por Rhipicephalus sanguineus y otro por Trichodectes canis. La prevalencia de D. caninum en pulgas fue del 9,5 %. Conclusión. La prevalencia de endoparásitos fue de 37,2 % y, la de ectoparásitos, de 13,1 %. Por primera vez en México se hizo un análisis de endoparásitos y ectoparásitos en una misma población de perros, así como el diagnóstico molecular de D. caninum.

Abstract | Introduction: Endoparasites and ectoparasites in dogs are of global distribution. The close relationship between dogs and man implies a risk for the transmission of zoonotic parasites. Therefore, it is necessary to determine the parasites hosted by dogs in specific areas and the factors associated with their presence. Objectives: To identify and to estimate the prevalence of endoparasites and ectoparasites in domiciled dogs in the Metropolitan area of Toluca, México, and the prevalence of D. caninum in fleas of the genus Ctenocephalides spp. Materials and methods: We collected samples from 402 domiciled dogs in four reference hospitals in the area in Toluca. We diagnosed endoparasites using direct smear, flotation, and sedimentation techniques and we performed the taxonomic identification of ectoparasites. Finally, the molecular diagnosis of D. caninum in fleas was made using the polymerase chain reaction technique (PCR). Results: A total of 37.2% of dogs were positive for endoparasites; the genera or species identified were Toxocara spp., Giardia spp., Ancylostoma spp., Cystoisospora spp., D. caninum, Taenia spp., and Trichuris vulpis; the prevalence of ectoparasites was 13.13%. We identified fleas of the species Ctenocephalides felis, Ctenocephalides canis; only one animal was parasitized with Rhipicephalus sanguineus and another one with Trichodectes canis; the prevalence of D. caninum in fleas was 9.5%. Conclusion: The prevalence of endoparasites was 37.2% while that of ectoparasites was 13.1%; this is the first analysis of endoparasites and ectoparasites conducted in the same population of dogs in México together with the molecular diagnosis of D. caninum in fleas.

Presentación atípica de toxocariasis infantil: a propósito de un caso / Atypical presentation of infant toxocariasis: about a case

Resumen Se presenta el caso de una niña de 8 años, procedente de la Amazonia peruana, con una presentación atípica de una toxocariasis. El cuadro clínico, de un mes de evolución, fue caracterizado por dolor abdominal crónico, palidez y geofagia, asociado a una masa abdominal y linfoadenopatías generalizadas. No hubo sintomatología respiratoria, dérmica, ocular o neurológica. En el hemograma se encontró una anemia y eosinofilia periférica acentuada y una eosinofilia moderada en el aspirado medular. El diagnóstico fUe confirmado por serología por el método de enzimoinmunoanálisis (ELISA), que mostró la presencia de anticuerpos anti-Toxocara de tipo IgG e IgM. Se administró tratamiento con albendazol 400 mg al día, durante cinco días, con una evolución favorable.

Abstract We present the case of an 8-year-old girl with an atypical presentation of toxocariasis, from the Peruvian Amazon. A month ago, the clinical presentation was characterized by the presence of abdominal pain, paleness and geophagia, associated with an abdominal mass and generalized lymphadenopathy. There were no respiratory, dermal, ocular or neurological symptoms. Marked peripheral eosinophilia was found in the blood count, and moderate eosinophilia in the spinal cord aspírate. The diagnosis was confirmed by serology with the enzyme-linked immunosorbent assay (ELISA), which showed the presence of IgG and IgM anti- Toxocara antibodies. Treatment with albendazole 400 mg once daily was administered for five days with favorable evolution.

Incidencia de toxocara canis en materia fecal de canes del albergue asociación protectora de animales Chuquisaca / Incidence of toxocara canis in fecal matter of canes del albergue protective association of animals Chuquisaca

La Toxocariosis es una enfermedad parasitaria ocasionada por larvas del género Toxocara. El parásito T. canis es uno de los tres nematodos más prevalentes en los estudios llevados a cabo en zonas urbanas de países como Bolivia, Perú, Argentina y México. Los huevos de T. canis son altamente resistentes a condiciones ambientales. El presente trabajo de investigación que se realizó en el mes de diciembre de 2017, tuvo como objetivo principal determinar la Incidencia de Toxocara canis en materia fecal de canes del Albergue Asociación Protectora de Animales Chuquisaca, en muestras de heces de 123 perros, las cuales fueron procesadas y analizadas en el laboratorio de la Caja de Salud Cordes del departamento de Chuquisaca, utilizando el método de Faust, dando como resultado que del total de perros muestreados el 17 % dieron positivo a Toxocara canis. Con relación a la edad, los perros más afectados fueron los del rango pertenecientes a menores de seis meses con un 91 %, en cuanto a la relación con el sexo del animal, no hubo una significancia importante, ya que las hembras positivas fueron de 51.9 %, mientras que en los machos fue de 48.1 %. El poco conocimiento de los encargados del Albergue y la falta de protección del mismo en el contacto con los animales puede llevar a contraer las diferentes enfermedades en el humano. Con todo esto se concluye que los cachorros menores de seis meses, sin importar su sexo, siempre serán los más afectados por este tipo de parásitos. Por lo cual se recomienda realizar una correcta desparasitación en los cachorros y en las hembras gestantes.

Toxocariosis is a parasitic disease caused by larvae of the genus Toxocara. The T. canis parasite is one of the three most prevalent nematodes in studies carried out in urban areas of countries such as Bolivia, Perú, Argentina and Mexico. T. canis eggs are highly resistant to environmental conditions. The present research work that was carried out in December 2017, had as main objective to determine the Incidence of Toxocara canis in fecal matter of dogs of the Chuquisaca Animal Protective Association Shelter, in samples of feces of 123 dogs, which were processed and analyzed in the laboratory of the Cordes Health Department of the department of Chuquisaca, using the Faust method, resulting in the total number of dogs sampled 17% tested positive for Toxocara canis. With regard to age, the most affected dogs were those of the range belonging to children under six months with 91%, regarding the relationship with the sex of the animal, there was no significant significance, since the positive females were 51.9 %, while in males it was 48.1%. The little knowledge of the managers of the Shelter and the lack of protection of the same in the contact with the animals can lead to contracting the different diseases in the human. With all this it is concluded that puppies under six months, regardless of sex, will always be the most affected by these types of parasites. Therefore, it is recommended to perform a correct deworming in puppies and in pregnant females.

Seroprevalence of Toxocara canis infection in preschool children and environmental contamination with Toxocara canis eggs in Yangpu District of Shanghai / 上海交通大学学报（医学版）

Objective • To investigate the seroprevalence of Toxocara canis (T. canis) from preschool children in Yangpu District of Shanghai, and to evaluate the environmental contamination with T. canis eggs in public areas. Methods • A cross-sectional study was performed. A total of 789 children from 7 kindergartens in Yangpu District of Shanghai were asked to fill up a questionnaire. Serum samples of 605 children were tested by using an enzyme linked immunosorbent assay for the detection of specific IgG antibody against T. canis. Sixty-seven soil samples and 69 fecal samples of dogs were collected from the neighborhood close to the kindergartens. DNAs were then extracted from all samples and amplified by PCR targeting T. canis ribosomal internal transcribed spacer 2 (ITS-2) gene fragments. Results • 1.0% of the serum samples were positive for IgG against T. canis. The positive rates of T. canis DNA in the soil and feces were 4.5% and 27.5%, respectively. More than 90.0% of the children had good habits of hand washing and their parents were aware of dog-related diseases and prevention. 6.8% of the children kept dogs at home and 77.8% of the dogs received anthelmintic treatment. 83.5% of the children reported stray dogs in the neighborhood but only 2.0% had regular contact with stray dogs. Conclusion • Seroprevalence of T. canis specific IgG was low among preschool children in this area. Good hygienic habits and prevention consciousness may be the main reasons for this result. But the high environmental contamination of T. canis eggs makes it necessary to prompt preventive public health measures which will play an important role in the prevention and treatment of ocular toxocariasis.

Toxocara canis en humanos, perros y suelos en ribera del Río de la Plata, provincia de Buenos Aires / Toxocara canis in humans, dogs and soil on the river side of Rio de la Plata, province of Buenos Aires / Toxocara canis em humanos, cães e solos nas margens do Rio da Prata, província de Buenos Aires

El objetivo de este trabajo fue describir la situación epidemiológica de toxocariosis en un hábitat ribereño. Se determinaron anticuerpos anti-toxocara por ELISA en sueros de 34 niños y 64 adultos, y se hallaron seroprevalencias de 32,3% y 45,3%, respectivamente. Esta fue alta en adultos y en niños de 2 a 3 años. Se realizaron 217 análisis coproparasitológicos de caninos y 23,04% fueron positivos para huevos de Toxocara canis. La distribución de caninos positivos por rango etario fue de 66% entre 1 y 6 meses; de 20,7% entre 6 y 12 meses; y de 10,3% en mayores de 12 meses. El porcentaje de animales parasitados por T. canis fue significativamente menor en relación a otros parásitos y disminuyó marcadamente con el aumento de la edad. Se analizaron 104 muestras de suelo y 1,92% de las mismas fueron positivas para huevos de T. canis. La escasa cantidad de huevos en suelos podría deberse a que los cachorros no se encontraban libres en los espacios públicos. En este barrio podría inferirse que el suelo no actuó como diseminador de esta parasitosis, sino que fueron de mayor relevancia factores como la tenencia de caninos menores de 1 año, el contacto estrecho con los mismos en ámbitos domiciliarios y las condiciones higiénico-sanitarias poco saludables.

The aim of this study was to describe the epidemiological situation of toxocariasis in a coastal habitat. Blood samples of 34 children and 64 adults were analyzed in order to determinate antibodies anti-toxocara by ELISA method. Prevalences of 32.3% and 45.3% were obtained respectively. A total of 217 coproparasitological canine analyses were performed, and 104 soil samples were analyzed. In humans, the seroprevalence of 32.4% in children and 45.3% in adults was found. In dogs, 50 samples were positive for T. canis eggs (23.04%). The distribution of canine positive for each age range yielded the following results: from 1 to 6 months, 66%; from 6 to 12 months, 20.7% and over 12 months, 10.3%. In soils, only 2 samples (1.92%) were positive for T. canis eggs. Seroloprevalence in humans was high, especially in adults and children aged 2 to 3 years. The percentage of parasitized animals by Toxocara was significantly lower in relation to other canine parasites and the percentage of dogs parasitized diminished significantly by increasing the age range. The low number of eggs found in soils could be due to the absence of puppies in public spaces. In this neighborhood, it can be inferred that the ground of public spaces did not act as a disseminator of this parasitosis, but that there were more relevant factors such as the possession of canines under 1 year of age, the close contact with them in residential areas, and unhealthy sanitary conditions.

O objetivo deste trabalho foi descrever a situação epidemiológica da toxocaríase em um habitat ripícola. Os anticorpos anti-toxocara foram determinados por ELISA em soros de 34 crianças e 64 adultos, com soroprevalência de 32,3% e 45,3%, respectivamente. Ela foi alta em adultos e em crianças de 2 a 3 anos de idade. Foram realizadas 217 análises coproparasitológicas caninas e 23,04% foram positivas para os ovos de Toxocara canis. A distribuição de caninos positivos por faixa etária foi de 66%, entre 1 e 6 meses, de 20,7%, entre 6 e 12 meses, e de 10,3% em maiores de 12 meses. A porcentagem de animais parasitados por T. canis foi significativamente menor em relação a outras parasitas e diminuiu marcadamente com o aumento da idade. Foram analisadas 104 amostras de solo e 1,92% delas foram positivas para ovos de T. canis. A escassa quantidade de ovos nos solos pode ser o resultado do fato de que os filhotes não estivessem livres nos espaços públicos. Poderia ser inferido que, nesse bairro, o solo não atuou como disseminador dessa parasitose, mas fatores como a posse de caninos menores de 1 ano de idade, um contato próximo com eles em ambientes domésticos e condições higiênico-sanitárias insalubres foram fatores de maior relevância.

Ocular toxocariasis caused by toxocara canis in an adult woman. case report

ABSTRACT Introduction: Toxocariasis is a zoonosis caused by the Toxocara canis and Toxocara cati nematodes larvae. These are intestinal parasites found in canids and felids, respectively. Case presentation: This paper presents the case of a 22-year-old woman from Caquetá, with a three-month history of vision loss in her left eye, eye pain, diplopia, photophobia and bilateral red eye. Retinal detachment in the left eye was diagnosed by ultrasound. The ophthalmology service made a differential diagnosis of retinoblastoma and pars planitis. Symptomatic management was initiated with oral and topical corticosteroids, obtaining symptom improvement, although loss of visual acuity persisted. Discussion: Coexistence and cohabitation of the patient with pets (dogs and cats) was an important factor to consider ocular toxocariasis. Complete blood count revealed mild leukocytosis and lymphocytosis without eo-sinophilia. Antibodies against Toxoplasma gondii and Taenia solium cysticercus were negative, as well as the VDRL. The ELISA test for Toxocara canis was positive, with IgG titers of 1:64 (positive >1:32, specificity >90%). Management with ophthalmic and systemic corticosteroids, albendazole and vitrectomy was initiated. The vitreous band was released by means of surgery, making the diplopia disappear, although residual peripheral granuloma persisted and will be operated by ophthalmology. Conclusions: Knowledge on ocular toxocariasis is important for physicians because it might be mistaken with retinoblastoma, a malignant neoplasm that may require enucleation of the eye.

RESUMEN Introducción. La toxocariasis es una zoonosis producida por las larvas de los nemato-dos Toxocara canis y Toxocara cati, parásitos intestinales de los cánidos y los félidos, respectivamente. Presentación del caso. Paciente femenino de 22 años de edad, procedente de Caquetá, Colombia, con un cuadro de 3 meses de evolución con pérdida de visión en ojo izquierdo, acompañada de dolor ocular, diplopia, fotofobia y ojo rojo bilateral, quien presenta desprendimiento de retina en ojo izquierdo diagnosticado por ecografia. La mujer asiste a oftalmologia, donde se hace diagnóstico diferencial con retinoblastoma y pars planitis. Se inicia manejo sintomático con corticoides orales y tópicos, con mejoria de la sintomatologia, pero persistencia de pérdida de la agudeza visual. Discusión. Al revisar historial de antecedentes socioeconómicos, la paciente convive con perros y gatos, por lo que se piensa en toxocariasis ocular. En el cuadro hemático se observa ligera leucocitosis y linfocitosis, sin eosinofilia. La determinación de anticuerpos anti-Toxoplasma gondii y anti-cisticerco de Taenia solium resultaron negativas, al igual que el VDRL. El test de ELISA para T. canis fue positivo, con unos titulos IgG de 1:64 (positivo >1:32, especificidad >90%). Se inicia manejo con corticoide oftálmico, sistémico, albendazol y vitrectomia. Con la intervención quirúrgica se libera banda vitrea, logrando la desaparición de la diplopia, pero persiste granuloma periférico residual, el cual será intervenido por oftalmologia. Conclusiones. Dada la posibilidad de ser confundida con un retinoblastoma -una neoplasia maligna que puede requerir la enucleación del ojo-, el conocimiento de esta forma de presentación de la toxocariasis es de suma importancia para los clinicos.

Developmental stages and viability of Toxocara canis eggs outside the host / Desarrollo y viabilidad de huevos de Toxocara canis

ABSTRACT Introduction: Toxocariasis is a soil-transmitted zoonotic disease caused mainly by ingestion of larvated eggs of Toxocara canis. Objectives: To study the morphology of the intraovular developmental stages of Toxocara canis in culture, characterize non-viable eggs and the sequences of larval molting and compare the viability of eggs at the early stages of division and at reaching full maturation. Material and methods: Observation of developing embryos and characterization of non-viable eggs were done using light microscope. The proportions of viable eggs during embryonation were compared to the proportions of viable mature eggs. Results: Cell division commenced after 24 hours of cultivation. Early stages were found to be present over a period of 3-5 days. The developmental stages identified were eggs with: One cell, two cells, three cells, four cells, early morula, late morula, blastula, gastrula, tadpole, pre-larva, first, second and third stage larva. Two larval molts occurred. Non-viable eggs had degenerated cytoplasm, thin or collapsed shell and the larvae did not move after exposure to light. No significant differences were found between the proportions of viable eggs from day five to day 21 as compared to viability of fully mature eggs (30 days). Conclusion: Developing embryos in the environment may be considered as a potential threat to the public health. The precise identification of developmental stages and the clear differentiation of viable and non-viable eggs can help in determining an accurate baseline rate of development that could be used in studies of ovicidal compounds.

RESUMEN Introducción. La toxocariasis es una enfermedad zoonótica transmitida por contacto con el suelo contaminado y causada principalmente por la ingestión de huevos larvados de Toxocara canis. Objetivos. Estudiar la morfología de los estadios intraovulares en desarrollo de T. canis en cultivo, caracterizar los huevos no viables y las secuencias de las mudas larvarias, y comparar la viabilidad de los huevos en las etapas tempranas de división y al alcanzar la maduración completa. Materiales y métodos. Se observó el desarrollo de los embriones y se caracterizaron los huevos no viables, mediante microscopía de luz. Se comparó la proporción de huevos viables con embrión con la de huevos maduros viables. Resultados. La división celular comenzó 24 horas después de iniciado el cultivo. Los estadios tempranos estuvieron presentes por un periodo de tres a cinco días. Los estadios de desarrollo identificados fueron: huevos con una célula, con dos células, con tres células y con cuatro células;mórula temprana, mórula tardía, blástula, gástrula, renacuajo, prelarva, primer, segundo y tercer estado larvario. Se presentaron dos mudas larvarias. Los huevos no viables tenían el citoplasma degradado, cubierta exterior delgada o colapsada, y su larva no se movía al exponerla a la luz. No se encontraron diferencias significativas entre la proporción de huevos viables del día 5 al día 21, al compararla con la viabilidad de los huevos completamente maduros (30 días). Conclusión. Los embriones en desarrollo en el medio ambiente pueden considerarse como un riesgo potencial para la salud pública. La identificación precisa de los estadios de desarrollo y la clara diferenciación de huevos viables y no viables, pueden ayudar a determinar con exactitud una tasa basal de desarrollo, la cual sería útil en el estudio de compuestos ovicidas.

Effect of sex on Toxocara canis larval migration to the cerebellum during experimental infection of Rattus norvegicus

The presence of Toxocara canis third instar larvae in the cerebellum of Rattus norvegicus may alter rodent behavior and movement. In this study, we investigated whether the sex of the rodent affects the migration of larvae to the cerebellum. Thirty-six Rattus norvegicus specimens (18 males and 18 females) were infected with 300 T. canis eggs and were euthanized after 60 days. The cerebellum was removed and treated with 0.5% HCl to recover the T. canis larvae. The number of larvae recovered from male rodents was significantly higher than in females, suggesting that the sex of the animal influences larval migration to the cerebellum

Larva migrans visceral. Presentación de un caso / Visceral larva migrans. Report of a case

RESUMEN La larva migrans visceral es una enfermedad que se produce al ingerir huevos infectantes de nematodos parásitos de gatos y perros (Toxocaracanis y Toxocaracati); los cuales eclosionan en el intestino del hombre y las larvas se distribuyen en todo el organismo, principalmente hígado, pulmón, corazón y cerebro. Las larvas en su migración dejan trazos de hemorragias, necrosis y células inflamatorias; algunas son destruidas por la respuesta inmune del huésped y otras forman granulomas eosinofílicos. Los síntomas dependen del tejido u órgano afectado, de la intensidad de la infección y del grado de la respuesta inmunológica inducida. Se presenta un caso del sexo masculino de 72 años que ingresa en el Servicio de Medicina del Hospital Militar Docente “Dr. Mario Muñoz Monroy”, de Matanzas, por cuadro de fiebre, diarreas, tos seca, astenia, anorexia y pérdida de peso al que se le diagnosticó larva migrans visceral. Por lo atípico de la edad del paciente y la complejidad del diagnóstico decidimos presentar este caso (AU).

ABSTRACT Visceral larva migrans is a disease produced after the ingestion of infectant eggs of cat´s and dog´s nematode parasites (Toxocara canis and Toxocara cati). These parasites harch in the men´s intestines and the larvas are distributed around the organism, mainly in the following organs: liver, lungs, hearth and brain. In their migration, the larvas leave traces of hemorrhage, necrosis and inflammatory cells; several of them are destroyed by the host´s immune answer and others form eosinophilic granulomas. The symptoms depend on the affected tissue or organ, on the infection intensity and on the level of induced immunologic answer. The case of a male patient, aged 72 years-old is presented. He entered the Medicine Service of the Teaching Military Hospital “Dr. Mario Muñoz Monroy”, of Matanzas with fever, diarrhea, dry cought, asthenia, anorexia and weight loss.Visceral larva migrans was diagnosed. The presentation of the case was decided because of the atypical patient´s age and the complexity of the diagnosis (AU).

Toxocara canis Mimicking a Metastatic Omental Mass from Sigmoid Colon Cancer: A Case Report

Toxocara canis is an important roundworm of canids and a fearsome animal parasite of humans. Human infections can lead to syndromes called visceral larva migrans (VLM), ocular larva migrans, neurotoxocariasis, and covert toxocariasis. VLM is most commonly diagnosed in children younger than 8 years of age, but adult cases are relatively frequent among those infected by ingesting the raw tissue of paratenic hosts in East Asia. This research reports the case of a 59-year-old man with sigmoid colon cancer, who visited our institution for surgery. An intraperitoneal mass was found on preoperative computed tomography, and it was thought to be a metastatic mass from sigmoid colon cancer. A postoperative histologic examination and serum test showed eosinophilic granuloma due to toxocariasis. Diagnosis of VLM is often difficult and highly suspicious in adults. Researchers suggest, although rarely, that VLM be included in the differential diagnosis as a cause of intraperitoneal tumors.

Hepatic Toxocariasis with Atypical CT and MR Imaging Findings: a Case Report

Hepatic toxocariasis is a type of visceral larva migrans caused by the migration of second-stage larvae of certain nematodes such as Toxocara canis to the liver. Histologically, the condition is characterized by granulomatous lesions containing eosinophils and inflammatory cells. We report a case of hepatic toxocariasis with atypical clinical and radiologic findings presenting as distinct, solitary hepatic nodule detected in a middle-aged woman.

Experimental toxocariasis in BALB/c mice: relationship between parasite inoculum and the IgG immune response

BALB/c mice were inoculated with 5-500 Toxocara canis infective eggs, and bled at 15-120 days post infection (dpi) to evaluate the dynamics of IgG antibody response and larvae distribution. Positive results were observed in all occasions for every inoculum, and a direct proportional relationship between antibody detection and the parasitic load was observed. In samples collected at 60 dpi, detection of IgG was more intense, especially with the 50 and 500 egg doses; also, a correlation between antibody level and egg count was observed with these two inocula. At 120 dpi, a decrease in antibody titer was observed for all groups; and at the end of the experiment, larvae were recovered from carcass, liver and brain. In the liver, larvae were only found in mice inoculated with 500 T. canis eggs. In carcasses, these were recovered in all groups, and the group inoculated with 50 eggs showed the highest percentage of larvae in the brain.

Infección al sistema nervioso por toxocara canis en Hospital Escuela Universitario, Honduras / Nervous system infection by Toxocara Canis in the University School Hospital, Honduras

La toxocariosis es una enfermedad provocada por nematodos; actualmente se cataloga una de las zoonosis prevalentes a nivel mundial, especialmente en áreas rurales, se presenta a cualquier edad de la vida. Se presenta el primer caso publicado de neurotoxocariosis canis en Honduras. Objetivo: orientar al lector sobre el comportamiento de esta enfermedad y su sospecha clínica en paciente con contacto canino. Caso clínico: paciente masculino con 14 meses de edad, en contacto con perros de su comunidad, con historia de fiebre y convulsiones; al examen físico hepatomegalia y signo Babinski (+). Laboratorialmente presentó hipereosinofilia y en estudio de imágenes edema cerebral difuso. Se realizó ELISA por Toxocara y resultó positivo, de acuerdo al resultado se sospechó toxocariosis no clásica. Conclusión: la presentación no típica de esta enfermedad es rara, la similitud de la sintomatología con otras enfermedades hace de la práctica clínica de difícil diagnóstico. Es importante tener presente esta forma no clásica de esta enfermedad...(AU)

Producción y evaluación del antígeno recombinante TES-30 de Toxocara canis para el inmunodiagnóstico de toxocariasis / Production and evaluation of the recombinant antigen TES-30 of Toxocara canis for the immunodiagnosis of toxocariasis

Introducción. Toxocara canis es un nematodo patógeno de cánidos que accidentalmente puede ser transmitido a los humanos. A pesar de la importancia de la serología para el diagnóstico de esta zoonosis, los kits diagnósticos usan antígenos crudos de excreción-secreción, en su mayoría glucoproteínas que no son específicas de especie, por lo cual pueden presentarse reacciones cruzadas con anticuerpos generados contra otros parásitos. Objetivos. Producir el antígeno recombinante TES-30 de T. canis y evaluarlo para el inmunodiagnóstico de la toxocariasis. Materiales y métodos. Se clonó el gen que codifica TES-30 en el vector de expresión pET28a (+), usando oligonucleótidos de cadena sencilla unidos mediante reacción en cadena de la polimerasa (PCR). La proteína rTES-30 se purificó por cromotografia de afinidad (Ni 2+ ). La reacción serológica de rTES-30 se evaluó mediante immunoblot . Teniendo en cuenta que no existe una prueba de referencia , se observó el comportamiento del antigeno en comparación con la prueba de rutina para el inmunodiagnóstico de la toxocariasis, es decir, la técnica ELISA convencional con antígenos de excreción-secreción. Resultados. El rTES-30 se produjo a partir de un cultivo de Escherichia coli LB, con un rendimiento de 2,25 mg/l y 95 % de pureza. La concordancia de la reacción entre el immunoblot rTES-30 y la ELISA convencional, fue de 73 % (46/63) y de 100 % con los 21 sueros no reactivos. De los 21 sueros con diagnóstico de otras parasitosis, 19 fueron reactivos con ELISA, mientras que tan solo siete fueron positivos con el immunoblot rTES-30. La concordancia entre la ELISA y el immunoblot fue moderada (índice kappa de 0,575; IC 95% 0,41-0,74). Conclusiones. Los datos presentados respaldan la utilidad del immunoblot r TES-3 0 para la confirmación de los posibles positivos por ELISA, no solo en los estudios epidemiológicos, sino también, como candidato para el desarrollo de pruebas diagnósticas de la toxocariasis ocular en Colombia.

Introduction: Toxocara canis is a pathogenic nematode of canines which can be accidentally transmitted to humans. Although serology is the most important diagnostic tool for this zoonosis, diagnostic kits use crude excretion/secretion antigens, most of them being glycoproteins which are not species-specific and may cross-react with antibodies generated against other parasites. Objectives: To produce the rTES-30 recombinant antigen of Toxocara canis and evaluate it in the immunodiagnosis of toxocariasis. Materials and methods: The gene that codes for TES-30 was cloned in the expression vector pET28a (+) using single-stranded oligonucleotides united by PCR. The protein rTES-30 was purified by Ni 2+ affinity chromotography. Seroreactivity of rTES-30 was evaluated by immunoblot. Given that there is no gold standard test, the behaviour of the antigen was compared with the method that is routinely used to immunodiagnose toxocariasis, i.e., the conventional ELISA technique using excretion/secretion antigens. Results: The rTES-30 was produced from an Escherichia coli LB culture which yielded 2.25 mg/L of the antigen with a purity of 95%. The results obtained showed 73% (46/63) concordance of reactivity between the rTES-30 immunoblot and the conventional ELISA, and 100% concordance with the non-reactive sera (21). Nineteen of the 21 sera positive for other parasitoses reacted with ELISA, while only seven of these were positive with the rTES-30 immunoblot. Concordance between the ELISA and the immunoblot was moderate (kappa coefficient: 0.575; 95% CI: 0.41- 0.74). Conclusions: The data presented show the potential of the rTES-30 inmunoblot for confirmation of possible ELISA positives, not only in epidemiological studies, but also as a candidate for the development of diagnostic tests for ocular toxocariasis in Colombia.

Toxocara canis-Associated Myelitis with Eosinophilic Pneumonia

The existence of Toxocara canis-specific antibodies has recently been reported in patients with atopic myelitis. Here, we report the case of a 35-year-old male patient admitted with a chief complaint of right lower limb hypoesthesia lasting for a month. The patient was diagnosed with eosinophilic pneumonia 3 months ago, and a spine MRI revealed the presence of myelitis in the cervicothoracic cord. After confirming the presence of hyper-IgE-emia and Toxocara canis antibodies, the patient was treated with steroids and albendazole treatment, which improved his symptoms. To our knowledge, this is the first case of Toxocara canis-associated myelitis with eosinophilic pneumonia.

Draft Genome of Toxocara canis, a Pathogen Responsible for Visceral Larva Migrans

This study aimed at constructing a draft genome of the adult female worm Toxocara canis using next-generation sequencing (NGS) and de novo assembly, as well as to find new genes after annotation using functional genomics tools. Using an NGS machine, we produced DNA read data of T. canis. The de novo assembly of the read data was performed using SOAPdenovo. RNA read data were assembled using Trinity. Structural annotation, homology search, functional annotation, classification of protein domains, and KEGG pathway analysis were carried out. Besides them, recently developed tools such as MAKER, PASA, Evidence Modeler, and Blast2GO were used. The scaffold DNA was obtained, the N50 was 108,950 bp, and the overall length was 341,776,187 bp. The N50 of the transcriptome was 940 bp, and its length was 53,046,952 bp. The GC content of the entire genome was 39.3%. The total number of genes was 20,178, and the total number of protein sequences was 22,358. Of the 22,358 protein sequences, 4,992 were newly observed in T. canis. Following proteins previously unknown were found: E3 ubiquitin-protein ligase cbl-b and antigen T-cell receptor, zeta chain for T-cell and B-cell regulation; endoprotease bli-4 for cuticle metabolism; mucin 12Ea and polymorphic mucin variant C6/1/40r2.1 for mucin production; tropomodulin-family protein and ryanodine receptor calcium release channels for muscle movement. We were able to find new hypothetical polypeptides sequences unique to T. canis, and the findings of this study are capable of serving as a basis for extending our biological understanding of T. canis.

Arginine kinase in Toxocara canis: Exon-intron organization, functional analysis of site-directed mutants and evaluation of putative enzyme inhibitors

OBJECTIVES@#To determine exon/intron organization of the Toxocara canis (T. canis) AK (TCAK) and to test green and black tea and several other chemicals against the activity of recombinant TCAK in the guanidino-specific region by site-directed mutants.@*METHODS@#Amplification of genomic DNA fragments containing introns was carried out by PCRs. The open-reading frame (1200 bp) of TCAK (wild type) was cloned into the BamH1/SalI site of pMAL-c2X. The maltose-binding protein-TCAK fusion protein was expressed in Escherichia coli TB1 cells. The purity of the expressed enzyme was verified by SDS-PAGE. Mutations were introduced into the guanidino-specific region and other areas of pMAL/TCAK by PCR. Enzyme activity was measured with an NADH-linked assay at 25 °C for the forward reaction (phosphagen synthesis).@*RESULTS@#Arginine kinase in T. canis has a seven-exon/six-intron gene structure. The lengths of the introns ranged from 542 bp to 2 500 bp. All introns begin with gt and end with ag. Furthermore, we measured the enzyme activity of site-directed mutants of the recombinant TCAK. The K value of the mutant (Alanine to Serine) decreased indicating a higher affinity for substrate arginine than the wild-type. The K value of the mutant (Serine to Glycine) increased to 0.19 mM. The K value (0.19 mM) of the double mutant (Alanine-Serine to Serine-Glycine) was slightly greater than in the wild-type (0.12 mM). In addition, several other chemicals were tested; including plant extract Azadiracta indica (A. indica), an aminoglycoside antibiotic (aminosidine), a citrus flavonoid glycoside (rutin) and a commercially available catechin mixture against TCAK. Green and black tea (1:10 dilution) produced 15% and 25% inhibition of TCAK, respectively. The extract of A. indica produced 5% inhibition of TCAK. Moreover, green and black tea produced a non-competitive type of inhibition and A. indica produced a mixed-type of inhibition on TCAK.@*CONCLUSIONS@#Arginine kinase in T. canis has a seven-exon/six-intron gene structure. However, further studies are needed to identify a specific compound within the extract causing the inhibitory effect and also to determine the molecular mechanisms behind inhibition of arginine kinase in T. canis.