Alterations of plasma circulating microRNAs in BALB/c mice with Toxocara canis visceral and cerebral larva migrans.

BACKGROUND: Human toxocariasis is a neglected parasitic disease characterised by the syndromes visceral, cerebral, and ocular larva migrans. This disease is caused by the migrating larvae of Toxocara roundworms from dogs and cats, affecting 1.4 billion people globally. Via extracellular vesicles (EVs), microRNAs have been demonstrated to play roles in host-parasite interactions and proposed as circulating biomarkers for the diagnosis and follow-up of parasitic diseases. METHODS: Small RNA-seq was conducted to identify miRNAs in the infective larvae of T. canis and plasma EV-containing preparations of infected BALB/c mice. Differential expression analysis and target prediction were performed to indicate miRNAs involved in host-parasite interactions and miRNAs associated with visceral and/or cerebral larva migrans in the infected mice. Quantitative real-time polymerase chain reaction (PCR) was used to amplify circulating miRNAs from the infected mice. RESULTS: This study reports host and parasite miRNAs in the plasma of BALB/c mice with visceral and cerebral larva migrans and demonstrates the alterations of these miRNAs during the migration of larvae from the livers through the lungs and to the brains of infected mice. After filtering unspecific changes in an irrelevant control, T. canis-derived miRNAs and T. canis infection-induced differential miRNAs are predicted to modulate genes consistently involved in mitogen-activated protein kinase (MAPK) signalling and pathways regulating axon guidance and pluripotency of stem in the infected mice with visceral and cerebral larva migrans. For these plasma circulating miRNAs predicted to be involved in host-parasite crosstalk, two murine miRNAs (miR-26b-5p and miR-122-5p) are experimentally verified to be responsive to larva migrans and represent circulating biomarker candidates for visceral and cerebral toxocariasis in BALB/c mice. CONCLUSIONS: Our findings provide novel insights into the crosstalk of T. canis and the mammalian host via plasma circulating miRNAs, and prime agents and indicators for visceral and cerebral larva migrans. A deep understanding of these aspects will underpin the diagnosis and control of toxocariasis in humans and animals.

[Toxocariasis in children from a subtropical region]. / Toxocariosis en niños de una region subtropical.

Toxocariasis is present worldwide but people living in areas with sanitary deficiencies are considered at the highest risk of infection, particularly children. The aim of this work was to know clinical and immunological aspects of infantile toxocariasis in a subtropical region in Argentina. For this purpose, 182 children of both sexes, 0-16 years old and with eosinophilia higher than 10%, living in Resistencia City (Northeast Argentina) were studied. Clinical examination, personal and epidemiological data recording, parasitological fecal examination and dosage of Toxocara canis IgG and IgM levels by EIE were performed; all positive sera were confirmed by Western Blot. Out of 182 children, 122 were positive for T. canis-IgG (67.0%); 28.8% lack of potable drinking water at home, 58.8% lack of sewerage facilities, 91.1% referred a close contact with dogs or cats, 30.0% had a history of geophagia and 86.7% lived along streets without pavement. The clinical forms of the infection were: 77.8% asymptomatic, 6.7% ocular larva migrans and 15.5% visceral larva migrans. In 22 children the serological follow up until 18 months after treatment showed 10 children without change in IgG levels, in 11 it decreased but remained high, and in one it increased. There were 19 children with high levels of T. canis-IgM; in 8 it decreased along treatment, in one it remained stable and 10 of them became negative. There was one child considered as a re-infection case. Results highlight the importance that health authorities should assign to this infection in regions with sanitary deficiencies, where toxocariasis is usually not recognized as a relevant public health problem.

Toxocariosis en niños de una region subtropical / Toxocariasis in children from a subtropical region

La toxocariosis está presente en todo el mundo, pero se considera en mayor riesgo a los habitantes de zonas com deficiencias sanitarias y particularmente a los niños. El objetivo de este trabajo fue conocer aspectos inmunológicos y clínicos de la infección infantil en un área subtropical de Argentina, para lo cual se estudiaron 182 niños de ambos sexos de la ciudad de Resistencia (Noreste de Argentina), de 0 a 16 años, con eosinofilia mayor al 10%. Se realizaron exámenes clínicos, encuestas epidemiológicas, exámenes copropa-rasitológicos y dosajes de IgG e IgM anti Toxocara canis por EIE; los sueros positivos fueron confirmados por Western Blot. De los 182 niños estudiados, 122 resultaron seropositivos (67%), 28.8% no contaban con agua potable en su domicilio, 58.8% no tenían cloacas, 91.1% habían tenido contacto con perros y/o gatos, 30.0% tenían antecedentes de geofagia y 86.7% vivían sobre calles sin pavimento. La infección se presentó en forma asintomática en el 77.8% de los casos, como larva migrans ocular en el 6.7% y como larva migrans visceral en el 15.5 % de los casos. En 22 niños el seguimiento serológico post-tratamiento hasta los 18 meses mostró que la IgG se mantuvo estable en 10 casos, en 11 disminuyó pero manteniendo valores elevados y em uno aumentó. Hubo 19 casos con IgM positiva; 8 disminuyeron sus títulos, uno se mantuvo estable y 10 se negativizaron. Hubo un caso de reinfección. Estos resultados reafirman la importancia que las autoridades sanitárias deben asignar a esta infección, particularmente en las regiones carenciadas, en las que habitualmente no se reconoce a la toxocariosis como un problema relevante de salud pública.

[Analysis of comparative immunological profiles of intraocular fluid and serum samples in patients suspected of ocular toxoplasmosis or toxocarosis]. / Ocena porównawczego profilu immunologicznego swoistych przeciwcial w plynie sródocznym i krwi obwodowej pacjentów podejrzanych o toksoplazmoze lub toksokaroze oczna.

High seroprevalence of Toxoplasma and Toxocara spp. in populations of children and adults in Poland constitutes a significant risk of supradiagnosed parasitic eye infections. We described the clinical characteristics in relation to the analysis of comparative immunological profiles of T. gondii-specific antibodies in aqueous humour and serum samples in patients with reactivated retinochoroiditis, and of Toxocara spp. ones in cases with posterior granuloma, fibrotic and calcified tumor-like masses simulating retinoblastoma, detected by ophthalmoscopy and echography. Intraocular synthesis of specific IgG antibodies was detected in anterior eye chamber fluid in 1/2 and 2/3 of patients respectively, strongly suspected of ocular toxoplasmosis or toxocarosis. The evidence of a local production of specific antibodies in intraocular fluid shown by the Western blot seems to be a valuable immunodiagnostic method for a final confirmation of eye lesions of parasitic origin and crucial in the choice of an appropriate treatment regimen.

[Ocular toxocarosis--as an example of diagnostic and therapeutic difficulties]. / Toksokaroza oczna--jako przyklad trudnosci diagnostycznych i terapeutycznych.

Diagnostic and therapeutic problems of ocular toxocarosis in patients with late pathological changes was observed. Multispecialistic methods (ophtalmological, radiological, immunoserological) in evaluation of patients were used. In the course of prolonged observation of patients treated many times with albendazole (Zentel, Smith Kline and Beecham GB) no improvement of vision and no regression of late and irreversible ocular pathology were noted.

Eosinophilic granuloma of the liver: a characteristic lesion with relationship to visceral larva migrans.

Children with the clinical syndrome of visceral larva migrans as a result of Toxocara species have typical lesions in the liver and other viscera, consisting of palisading granulomas that contain numerous eosinophils and often Charcot-Leyden crystals; recognizable parasites are uncommon. Similar eosinophilic granulomas that are found incidentally in adults often cause diagnostic problems. To define better the clinical, laboratory, and pathologic features of these lesions, we reviewed 43 cases of hepatic eosinophilic granuloma (excluding cases of Langerhans' cell histiocytosis) collected in the files of the AFIP over a period of 31 years. The eosinophilic granulomas were found in patients of all ages (range 12 months to 77 years); 30% were younger than 20 years. There were 26 male and 17 female patients. Most patients (26 of 43; 60%) were asymptomatic, and the lesions were discovered incidentally. Others had fever (20%) or abdominal pain (20%). The granulomas were typically multiple (61%), with central necrosis surrounded by a mixed inflammatory infiltrate with numerous eosinophils and variable numbers of neutrophils. lymphocytes, and a palisade of epithelioid histiocytes and/or giant cells. Charcot-Leyden crystals were present in 19 cases (44%). Remnants of parasites (eight Toxocara sp., two Capillaria sp.) were identified in the tissue in 10 patients. There was a positive serologic test for Toxocara sp. in five additional cases. Immunohistochemical staining using polyclonal antiserum against Toxocara canis larvae demonstrated positivity in macrophages in eight of 13 cases tested. We conclude that identification of an eosinophilic granuloma in the liver should suggest the diagnosis of visceral larva migrans and prompt a search for the causative organism with serial sectioning of the block and serologic tests for Toxocara and other causative parasites.

Oxidative metabolism of the human eosinophil.

We have compared the oxidative metabolism of human eosinophils (80%-90% purity) to that of neutrophils. Hexose monophosphate (HMP) shunt activity of eosinophils was higher than that of neutrophils under either resting or phagocytizing conditions. Eosinophil HMP shunt activity also was stimulated by phorbol myristate acetate, a membrane-active agent. Eosinophils showed a marked incorporation of 125I into trichloroacetic acid-insoluble material under resting conditions, which increased markedly during phagocytosis. Eosinophils likewise showed a greater reduction of nitroblue tetrazolium dye during phagocytosis than did neutrophils. Measurement of other parameters of oxidative metabolism indicated that eosinophils generated superoxide anion following phagocytosis and also elicited a burst of chemiluminescence similar to that observed during phagocytosis by neutrophils. Measurement of NADPH oxidase activity demonstrated that this enzyme was 3-6 times more active in fractions isolated from eosinophils than in corresponding fractions isolated from neutrophils; this was observed over a range of substrate concentrations. The eosinophil enzyme sedimented differently than the neutrophil enzyme with differential centrifugation; neither showed sedimentation characteristics of peroxidase. These data indicate that eosinophils possess a similar, although in some ways more potent, oxidative burst than neutrophils and are consistent with a role for NADPH oxidase in the initiation of that burst.