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 Influence of mouse strain, infective dose and larval burden in the brain on activity in Toxocara-infected mice

2001 ◽  
Vol 75 (1) ◽  
pp. 23-32 ◽  
Author(s):  
D.M. Cox ◽  
C.V. Holland
Keyword(s):  
Mouse Strain ◽  
Post Infection ◽  
Home Cage ◽  
Brain Activity ◽  
Toxocara Canis ◽  
Cage Activity ◽  
Home Cage Activity ◽  
The Brain ◽  
Larval Recovery ◽  
Larval Burden

Outbred LACA mice and inbred NIH mice were administered low (100 ova), medium (1000 ova), high (3000 ova) and trickle (4×250 ova) doses ofToxocara canisova and the effect of infection on activity was examined with respect to: (i) the dose of ova administered and (ii) the number of larvae recovered from the brain. Larval recovery from the brain was significantly reduced in NIH mice compared to LACA mice for the 1000, 3000 and trickle doses. Mice from each strain were divided into larval intensity groupings based upon the number of larvae recovered from their brain. Activity for each mouse was measured pre- and post-infection by observing its behaviour in the home cage. Activity was assessed by monitoring six different independent categories of murine behaviour – ambulation, grooming, rearing, digging, climbing and immobility. Within each behavioural category, the duration of time spent at each behaviour per mouse within one thousandth of a second, the number of short bouts performed and the number of long bouts of behaviour performed were recorded over a 20 min period. Activity of LACA and NIH mice differed prior to infection. LACA mice spent more time immobile compared to NIH mice, which ambulated and climbed more. Variations in activity were also observed between groups of mice prior to infection. The effect of infection differed by strain, by dose and by larval intensity. Post-infection LACA mice became more immobile and ambulated less. NIH mice showed reduced immobility, but while ambulation decreased digging and climbing increased post-infection. Short bouts of activity remained unchanged among LACA mice post-infection but showed an increase for some behaviours in NIH mice.

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.

Variation in the larval recovery ofToxocara canisfrom the murine brain: implications for behavioural studies

1997 ◽  
Vol 71 (3) ◽  
pp. 253-256 ◽  
Author(s):  
H. Skerrett ◽  
C.V. Holland
Keyword(s):  
Post Infection ◽  
Toxocara Canis ◽  
High Dose ◽  
Murine Brain ◽  
The Brain ◽  
Larval Recovery ◽  
Migratory Pathway

AbstractThe migratory pathway ofToxocara canislarvae was determined by infecting mice with a low, medium or high dose of embryonatedT. caniseggs and determining numbers of larvae present in the brain, liver, lungs, kidneys and muscle on days 5, 14 and 26 post infection. Variation was seen in the numbers of larvae recorded in the organs of mice which had received the same number of eggs and were at the same stage of infection. This variation was particularly marked in the brain indicating that, for the purposes of behavioural studies, the actual numbers of larvae found in the brain rather than the number assumed from the dose would have to be taken into account when analysing the behaviour of infected mice.

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.

The use of 35S-labelled Toxocara canis to determine larval numbers in tissues

1992 ◽  
Vol 66 (4) ◽  
pp. 279-287 ◽  
Author(s):  
K. C. Carter
Keyword(s):  
Post Infection ◽  
Half Life ◽  
Toxocara Canis ◽  
Second Stage ◽  
Infective Larvae ◽  
Secretory Products ◽  
Formed Part ◽  
Antibody Levels ◽  
The Brain

ABSTRACTThe potential of using 35S-labelled larvae to determine the number of second-stage Toxocara canis larvae present in the tissues of infected animals was assessed. Infective larvae were labelled by in vitro culture with medium containing 35S-methionine. The amount of radiolabel attached to larvae decayed exponentially with time and had an in vitro mean half life of 3·54±0·65 days. The ‘lost’ radiolabel was incorporated into proteins which formed part of the worm's excretory/secretory products. The levels of radioactivity present in different organs of BALB/c mice, infected with 35S-labelled T. canis larvae, varied over the course of infection. Initially most of the radioactivity was present in liver, but over the course of infection 35S liver levels gradually decreased and brain levels increased. By day 14 post-infection the majority of the isotope was present in the brain (p<0·01). Assessment of antibody levels on day 14 post-infection showed that infection with 35S labelled T. canis larvae induced the production of parasite-specific IgM, IgG and IgG1 antibodies.

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