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Larval migration in PERL chambers as an in vitro model for percutaneous infection stimulates feeding in the canine hookworm Ancylostoma caninum.

Franke D, Strube C, Epe C, Welz C, Schnieder T - Parasit Vectors (2011)

Bottom Line: Additionally, infective larvae of A. caninum were activated via serum-stimulation and feeding behaviour was analysed and compared between percutaneously migrated and serum-stimulated larvae.The medium beneath the skin had no effect on migration ratio, and no significant difference between the migration ratios through fresh and frozen/thawed skin was observed.The observed difference in time course of resumption of feeding indicates that percutaneously migrated larvae are not identical to serum-stimulated larvae, which are currently representing the model for early parasitic stages.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute for Parasitology, University of Veterinary Medicine Hannover, Buenteweg 17, 30559 Hannover, Germany.

ABSTRACT

Background: Ancylostoma caninum third-stage larvae are the non-feeding infective stage of this parasite and are able to infect potential hosts via different infection routes. Since percutaneous infection is one of the most important routes and skin penetration is the first step into parasitic life, an existing in vitro model for percutaneous migration was modified and evaluated. The main parameter used to evaluate migration was the migration ratio (migrated larvae as a percentage of total number of larvae recovered). Additionally, the skin lag was calculated, expressing the percentage of larvae remaining in the skin and therefore not being recovered. Since initiation of feeding is proposed to be an important step in the transition from free-living to parasitic A. caninum larvae, feeding assays were performed with in vitro percutaneously migrated larvae. Additionally, infective larvae of A. caninum were activated via serum-stimulation and feeding behaviour was analysed and compared between percutaneously migrated and serum-stimulated larvae.

Results: Maximum skin migration levels of infective larvae were observed at temperatures above 32°C when larvae were placed on the epidermal side of skin for more than 12 hours. The medium beneath the skin had no effect on migration ratio, and no significant difference between the migration ratios through fresh and frozen/thawed skin was observed. Maximum feeding levels of 93.2% were observed for percutaneously migrated larvae after 48 h incubation, whereas serum-stimulated larvae reached the maximum of 91.0% feeding larvae after 24 h.

Conclusions: The PERL chamber system was optimised and standardised as an in vitro model for percutaneous migration. The larvae recovered after percutaneous migration showed characteristic signs of activation similar to that of serum-stimulated larvae. The observed difference in time course of resumption of feeding indicates that percutaneously migrated larvae are not identical to serum-stimulated larvae, which are currently representing the model for early parasitic stages.

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Effect of temperature on the migration ratio of L3 after ≥ 12h of incubation. Each point represents the mean ± SD (n=6). Larvae were incubated in PERL chambers at 7°C, 22°C, 32°C, and 37°C, respectively.
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Figure 3: Effect of temperature on the migration ratio of L3 after ≥ 12h of incubation. Each point represents the mean ± SD (n=6). Larvae were incubated in PERL chambers at 7°C, 22°C, 32°C, and 37°C, respectively.

Mentions: The incubation temperature had significant effects on the migration ratios (Kruskal-Wallis One-Way ANOVA, p < 0.001; H = 29.357 with 3 degrees of freedom. For illustration of results refer to Figure 3). At 7°C no larvae were recovered from the acceptor compartment. With higher temperatures the migration ratio increased: at 22°C incubation temperature, the mean migration ratio was 62.9%, and at 32°C and 37°C, respectively, the migration ratio was near 90% (detailed results including mean skin lag are listed in Table 2). The migration ratios at 32°C and 37°C were not statistically significantly different (Dunn's test, p > 0.05), in contrast to the differences to the migration ratios at lower temperatures (Dunn's test, p < 0.05). The skin lag was also significantly different between the setups (One-Way ANOVA; p < 0.001). It was highest at an incubation temperature of 22°C and significantly higher than the skin lag at 32°C and 37°C, respectively. Furthermore, the skin lag at 7°C was significantly higher than at 32°C (Holm-Sidak method, p < 0.01). The skin lag did not differ significantly between the experiments at 32°C and 37°C, neither did the skin lag at 7°C from those at 22°C and 37°C (Holm-Sidak method, p > 0.01).


Larval migration in PERL chambers as an in vitro model for percutaneous infection stimulates feeding in the canine hookworm Ancylostoma caninum.

Franke D, Strube C, Epe C, Welz C, Schnieder T - Parasit Vectors (2011)

Effect of temperature on the migration ratio of L3 after ≥ 12h of incubation. Each point represents the mean ± SD (n=6). Larvae were incubated in PERL chambers at 7°C, 22°C, 32°C, and 37°C, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3037914&req=5

Figure 3: Effect of temperature on the migration ratio of L3 after ≥ 12h of incubation. Each point represents the mean ± SD (n=6). Larvae were incubated in PERL chambers at 7°C, 22°C, 32°C, and 37°C, respectively.
Mentions: The incubation temperature had significant effects on the migration ratios (Kruskal-Wallis One-Way ANOVA, p < 0.001; H = 29.357 with 3 degrees of freedom. For illustration of results refer to Figure 3). At 7°C no larvae were recovered from the acceptor compartment. With higher temperatures the migration ratio increased: at 22°C incubation temperature, the mean migration ratio was 62.9%, and at 32°C and 37°C, respectively, the migration ratio was near 90% (detailed results including mean skin lag are listed in Table 2). The migration ratios at 32°C and 37°C were not statistically significantly different (Dunn's test, p > 0.05), in contrast to the differences to the migration ratios at lower temperatures (Dunn's test, p < 0.05). The skin lag was also significantly different between the setups (One-Way ANOVA; p < 0.001). It was highest at an incubation temperature of 22°C and significantly higher than the skin lag at 32°C and 37°C, respectively. Furthermore, the skin lag at 7°C was significantly higher than at 32°C (Holm-Sidak method, p < 0.01). The skin lag did not differ significantly between the experiments at 32°C and 37°C, neither did the skin lag at 7°C from those at 22°C and 37°C (Holm-Sidak method, p > 0.01).

Bottom Line: Additionally, infective larvae of A. caninum were activated via serum-stimulation and feeding behaviour was analysed and compared between percutaneously migrated and serum-stimulated larvae.The medium beneath the skin had no effect on migration ratio, and no significant difference between the migration ratios through fresh and frozen/thawed skin was observed.The observed difference in time course of resumption of feeding indicates that percutaneously migrated larvae are not identical to serum-stimulated larvae, which are currently representing the model for early parasitic stages.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute for Parasitology, University of Veterinary Medicine Hannover, Buenteweg 17, 30559 Hannover, Germany.

ABSTRACT

Background: Ancylostoma caninum third-stage larvae are the non-feeding infective stage of this parasite and are able to infect potential hosts via different infection routes. Since percutaneous infection is one of the most important routes and skin penetration is the first step into parasitic life, an existing in vitro model for percutaneous migration was modified and evaluated. The main parameter used to evaluate migration was the migration ratio (migrated larvae as a percentage of total number of larvae recovered). Additionally, the skin lag was calculated, expressing the percentage of larvae remaining in the skin and therefore not being recovered. Since initiation of feeding is proposed to be an important step in the transition from free-living to parasitic A. caninum larvae, feeding assays were performed with in vitro percutaneously migrated larvae. Additionally, infective larvae of A. caninum were activated via serum-stimulation and feeding behaviour was analysed and compared between percutaneously migrated and serum-stimulated larvae.

Results: Maximum skin migration levels of infective larvae were observed at temperatures above 32°C when larvae were placed on the epidermal side of skin for more than 12 hours. The medium beneath the skin had no effect on migration ratio, and no significant difference between the migration ratios through fresh and frozen/thawed skin was observed. Maximum feeding levels of 93.2% were observed for percutaneously migrated larvae after 48 h incubation, whereas serum-stimulated larvae reached the maximum of 91.0% feeding larvae after 24 h.

Conclusions: The PERL chamber system was optimised and standardised as an in vitro model for percutaneous migration. The larvae recovered after percutaneous migration showed characteristic signs of activation similar to that of serum-stimulated larvae. The observed difference in time course of resumption of feeding indicates that percutaneously migrated larvae are not identical to serum-stimulated larvae, which are currently representing the model for early parasitic stages.

Show MeSH
Related in: MedlinePlus