Evidence for the involvement of the optic nerve as a migration route for larvae in ocular toxocariasis of Mongolian gerbils

2003 ◽  
Vol 77 (4) ◽  
pp. 311-315 ◽  
Author(s):  
E. Hayashi ◽  
N. Akao ◽  
K. Fujita
Keyword(s):  
Optic Nerve ◽  
Late Phase ◽  
Toxocara Canis ◽  
Meriones Unguiculatus ◽  
Migration Route ◽  
Mongolian Gerbils ◽  
Ocular Toxocariasis ◽  
Optic Chiasma ◽  
Two Phases ◽  
The Brain

AbstractAlthough Toxocara canis, an important pathogen of ocular disease, tends to migrate to the eye, the precise migratory route has yet to be determined experimentally. Mongolian gerbils, Meriones unguiculatus, known as a useful animal model for human toxocariasis, were used to investigate the migration route toward the eyes. Infective larvae of T. canis were directly inoculated into the intracranial region. Haemorrhagic lesions or larvae were observed in 56.3% of cases. Histopathologically, a larva was observed in the optic nerve of gerbils 6 days after inoculation, and two larvae were found in the optic chiasma in the gerbils having a haemorrhage in the retina 9 days after inoculation. These results indicate that T. canis migrates from the brain to the eye through the optic nerve. Considering these data and previous studies showing that the ocular changes appear as early as 3 days of infection in the oral-administrated gerbils, there are two phases in the migration to the retina: a haematogenous early phase and an optic nerve route late phase.

A developmental and ultrastructural study of the optic chiasma in Xenopus

Development ◽  
1988 ◽  
Vol 102 (3) ◽  
pp. 537-553
Author(s):  
M.A. Wilson ◽  
J.S. Taylor ◽  
R.M. Gaze
Keyword(s):  
Optic Nerve ◽  
Cell Mass ◽  
Light And Electron Microscopy ◽  
Optic Tract ◽  
Retinal Ganglion ◽  
Intercellular Spaces ◽  
Optic Chiasma ◽  
Cell Processes ◽  
Optic Axons ◽  
The Brain

The structure of the optic chiasma in Xenopus tadpoles has been investigated by light and electron microscopy. Where the optic nerve approaches the chiasma, a tongue of cells protrudes from the periventricular cell mass into the dorsal part of the nerve. Glial processes from this tongue of cells ensheath fascicles of optic axons as they enter the brain. Coincident with this partitioning, the annular arrangement of axons in the optic nerve changes to the laminar organization of the optic tract. Beyond the site of this rearrangement, all newly growing axons accumulate in the ventral-most part of the nerve and pass into the region between the periventricular cells and pia which we have called the ‘bridge’. This region is characterized by a loose meshwork of glial cell processes, intercellular spaces and the presence of both optic and nonoptic axons. In the bridge, putative growth cones of retinal ganglion cell axons are found in the intercellular spaces in contact with both the glia and with other axons. The newly growing axons from each eye cross in the bridge at the midline and pass into the superficial layers of the contralateral optic tracts. As the system continues to grow, previous generations of axon, which initially crossed in the existing bridge, are displaced dorsally and caudally, forming the deeper layers of the chiasma. At their point of crossing in the deeper layers, these fascicles of axons from each eye interweave in an intimate fashion. There is no glial segregation of the older axons as they interweave within the chiasma.

First in vitro isolation of Neospora caninum from a naturally infected adult dairy cow in Slovakia

2011 ◽  
Vol 56 (2) ◽  
Author(s):  
Katarína Reiterová ◽  
Silvia Špilovská ◽  
Andrea Čobádiová ◽  
Rastislav Mucha
Keyword(s):  
Dairy Cow ◽  
Neospora Caninum ◽  
Brain Homogenate ◽  
Vero Cells ◽  
Meriones Unguiculatus ◽  
Post Inoculation ◽  
Mongolian Gerbils ◽  
The Impact ◽  
The Brain

AbstractThe impact of in vitro isolation and molecular characterisation of Neospora caninum as well as sequence analyses was studied. The brain homogenate of a naturally Neospora-infected dairy cow (positive in ELISA and Western blot) was intraperitoneally inoculated into Mongolian gerbils (Meriones unguiculatus). The brain of gerbils on day 60 post-inoculation was homogenized, and, after trypsin-digestion, cultured on Vero cells. Neospora-like tachyzoites were first observed after 77 days of cultivation. The parasite was confirmed by polymerase chain reaction (PCR) using Neospora-specific primers Np21 and Np6. The PCR product of the first Slovak isolate (NC-SKB1) was subsequently sequenced and published in GenBank under accession number GU300774. Sequencing and BLAST search identified the isolate as N. caninum.

scholarly journals Detection of Toxocara canis larvae by PCR in the liver of experimentally infected Mongolian gerbils (Meriones unguiculatus)

2008 ◽  
Vol 45 (3) ◽  
pp. 147-149 ◽  
Author(s):  
A. Borecka ◽  
J. Gawor ◽  
M. Niedworok ◽  
B. Sordyl
Keyword(s):  
Clinical Manifestations ◽  
Toxocara Canis ◽  
Meriones Unguiculatus ◽  
Mongolian Gerbils ◽  
Igg Antibodies ◽  
Chain Reaction ◽  
Specific Igg ◽  
Pcr Method ◽  
Polymerase Chain ◽  
Specific Igg Antibodies

AbstractToxocariasis is a common human zoonosis, which induces a clinically unapparent course of infection. Diagnosis is difficult and relies upon serological testing (searching of specific IgG antibodies by ELISA), laboratory abnormalities and clinical manifestations. The polymerase chain reaction (PCR) technique was adapted for the detection of Toxocara canis larvae in a host tissue. Mongolian gerbils (Meriones unguiculatus) were used as an animal model for human toxocariasis. 8 animals were inoculated with 1000 T. canis eggs, four uninfected were used as control. At 3, 5, 7, and 14 days post-infection, 2 infected and 1 control gerbil were killed and their livers were used for molecular analysis. Specific primer in the PCR reaction allowed identification of T. canis larvae, with the parasite gDNA found in the liver of all infected gerbils. The results indicate that the PCR method has a potential as a supporting technique for the diagnosis of human toxocariasis.

Larval migration of the ascarid nematode Toxocara canis following infection and re-infection in the gerbil Meriones unguiculatus

2015 ◽  
Vol 90 (5) ◽  
pp. 569-576 ◽  
Author(s):  
M.C. Flecher ◽  
C. Musso ◽  
I.V.F. Martins ◽  
F.E.L. Pereira
Keyword(s):  
Toxocara Canis ◽  
Meriones Unguiculatus ◽  
Infected Group ◽  
Migration Patterns ◽  
Inflammatory Reactions ◽  
Larval Migration ◽  
T Helper 2 ◽  
The Brain ◽  
Histology And Immunohistochemistry ◽  
Formalin Fixed

AbstractA morphological and immunohistochemical study of larval migration patterns was performed in gerbils that were infected once (primary infected group) or twice (secondary infected group) with 1500 eggs of Toxocara canis. Animals from the primary infected and the re-infected group were killed at different times after infection, and larvae were counted in the intestines, liver, lungs and brain. Fragments of all organs were formalin fixed and paraffin embedded for histology and immunohistochemistry analyses (using polyclonal anti-Toxocara serum raised in rabbits infected with T. canis). In the primary infected group, larvae were more abundant in the intestine at 24 h, in the liver and lungs between 24 and 72 h and in the brain after 96 h; larvae predominated in the brain for up to 60 days after infection. In the re-infected group, an increase in the number of larvae in the liver and a reduction in the number of larvae in the brain was observed up to 60 days after re-infection. Inflammatory reactions were absent or limited. Eosinophils and loose granulomata were observed around the larvae and their antigens in the primary infected group and were more severe. Many eosinophils and typical epithelioid granulomata were observed around larvae in the re-infected group. These results demonstrate that the migration pattern of T. canis larvae in gerbils is similar to that in mice and rats, exhibiting a late neurotropic stage. In the re-infected group, there was histological evidence of an adaptive T-helper 2 (Th-2) response, and larvae were apparently retained within granulomata in the liver, without obvious signs of destruction.

Migration behaviour and pathogenesis of five ascarid nematode species in the Mongolian gerbil Meriones unguiculatus

2007 ◽  
Vol 81 (1) ◽  
pp. 43-47 ◽  
Author(s):  
S. Cho ◽  
M. Egami ◽  
H. Ohnuki ◽  
Y. Saito ◽  
S. Chinone ◽  
...  
Keyword(s):  
Mongolian Gerbil ◽  
Post Infection ◽  
Nematode Species ◽  
Toxocara Canis ◽  
Similar Rate ◽  
Meriones Unguiculatus ◽  
Ocular Manifestations ◽  
Migration Behaviour ◽  
Characteristic Features ◽  
The Brain

AbstractTo understand the characteristic features of the Mongolian gerbil, Meriones unguiculatus, as an animal model of ascarid infections, the migration behaviour and pathogenesis of larvae were investigated in experimentally infected gerbils. Embryonated eggs from each of Toxocara canis,Baylisascaris procyonis, B. transfuga, Ascaris suum, and A. lumbricoides were orally inoculated into gerbils and larvae were recovered from various organs at designated periods. In T. canis-infected gerbils, larvae were present in the liver 3 days after infection and in the skeletal muscle and brain via the heart and lungs at a similar rate. In B. procyonis- and B. transfuga-infected gerbils, larvae were present in the lungs within 24 h after infection, with some having reached the brain by that time. After 24 h, larvae of B. procyonis tended to accumulate in the brain, while those of B. transfuga accumulated in skeletal muscles. In A. suum- and A. lumbricoides-infected gerbils, larvae remained in the liver on day 5 post-infection and elicited pulmonary haemorrhagic lesions, which disappeared 7 days after initial infection. Thereafter, no larvae of any type were recovered. Ocular manifestations were frequently observed in T. canis- and B. procyonis infected gerbils, but were rare in B. transfuga-infected gerbils. In the cases of A. suum and A. lumbricoides, migration to the central nervous system and eyes was extremely rare, and larvae had disappeared by 2 weeks post-infection. Fatal neurological disturbances were observed in B. procyonis-infected gerbils, whereas irreversible non-fatal neurological symptoms were observed in the case of B. transfuga.

scholarly journals Endocrine Dysfunction in Children with Zika-Related Microcephaly Who Were Born during the 2015 Epidemic in the State of Pernambuco, Brazil

Viruses ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 1
Author(s):  
Andréia Veras Gonçalves ◽  
Demócrito de B. Miranda-Filho ◽  
Líbia Cristina Rocha Vilela ◽  
Regina Coeli Ferreira Ramos ◽  
Thalia V. B. de Araújo ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Viral Infections ◽  
Case Series ◽  
Optic Nerve Hypoplasia ◽  
Endocrine Dysfunction ◽  
Careful Monitoring ◽  
Early Puberty ◽  
Growth Impairment ◽  
Appropriate Treatment ◽  
The Brain

Congenital viral infections and the occurrence of septo-optic dysplasia, which is a combination of optic nerve hypoplasia, abnormal formation of structures along the midline of the brain, and pituitary hypofunction, support the biological plausibility of endocrine dysfunction in Zika-related microcephaly. In this case series we ascertained the presence and describe endocrine dysfunction in 30 children with severe Zika-related microcephaly from the MERG Pediatric Cohort, referred for endocrinological evaluation between February and August 2019. Of the 30 children, 97% had severe microcephaly. The average age at the endocrinological consultation was 41 months and 53% were female. The most frequently observed endocrine dysfunctions comprised short stature, hypothyroidism, obesity and variants early puberty. These dysfunctions occurred alone 57% or in combination 43%. We found optic nerve hypoplasia (6/21) and corpus callosum hypoplasia (20/21). Seizure crises were reported in 86% of the children. The most common—and clinically important—endocrine dysfunctions were pubertal dysfunctions, thyroid disease, growth impairment, and obesity. These dysfunctions require careful monitoring and signal the need for endocrinological evaluation in children with Zika-related microcephaly, in order to make early diagnoses and implement appropriate treatment when necessary.

scholarly journals Bioavailability of β-carotene (βC) from purple carrots is the same as typical orange carrots while high-βC carrots increase βC stores in Mongolian gerbils(Meriones unguiculatus)

2006 ◽  
Vol 96 (2) ◽  
pp. 258-267 ◽  
Author(s):  
Mandy Porter Dosti ◽  
Jordan P. Mills ◽  
Philipp W. Simon ◽  
Sherry A. Tanumihardjo
Keyword(s):  
Public Health ◽  
Vitamin A ◽  
Phenolic Acids ◽  
Health Problem ◽  
Public Health Problem ◽  
Meriones Unguiculatus ◽  
Mongolian Gerbils ◽  
Alternative Source ◽  
Β Carotene

Vitamin A (VA) deficiency is a worldwide public health problem. Biofortifying existing sources of β-carotene (βC) and increasing dietary βC could help combat the issue. Two studies were performed to investigate the relative βC bioavailability of a βC supplement to purple, high-βC orange, and typical orange carrots using Mongolian gerbils (Meriones unguiculatus). In study 1, which used a traditional bioavailability design, gerbils (n32) received a diet containing orange, purple, or white carrot powder, or white carrot powder +a βC supplement. In study 2, which included βC-biofortified carrots, gerbils (n 39) received orange, high-βC orange, purple, or white carrot powder in their diet. Both studies lasted 21 d and the gerbils were killed to determine the effect of carrot type or supplement on serum and liver βC, α-carotene, and VA concentrations. Liver stores of βC or VA in the gerbils did not differ between orange and purple carrot diets when equal amounts of βC from each of the diets were consumed (P>0·05). Both the orange and purple carrot diet resulted in higher liver VA compared with the supplement (P<0·05). High-βC carrots resulted in more than 2-fold higher βC and 1·1 times greater VA liver stores compared with typical orange carrots (P<0·05). These results suggest that high-βC carrots may be an alternative source of VA to typical carrots in areas of VA deficiency. Second, phenolics including anthocyanins and phenolic acids in purple carrot do not interfere with the bioavailability of βC from purple carrots.

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