title: Temperature and the development and survival of infective Toxocara canis larvae.
abstract: The influence of temperature on the development and survival of Toxocara canis larvae was investigated under laboratory conditions, in water at 15, 20, 25, 30 and 35°C and at room temperature 22°C ± 1°C. T. canis eggs were able to develop to the larvated stage at all the tested temperatures. Development rate increased with temperature. Linear regression of development rate against temperature predicted a lower development threshold of 11.8°C. Eggs survived cooling to 1 and -2°C for 6 weeks, and could develop to the infective, larvated stage when transferred to higher temperatures, but their development rates were then retarded compared with non-chilled eggs. Larvated eggs remained viable after 7 weeks of incubation across the tested temperature range, with the highest percentage viability (47%) obtained at 25°C. Development of eggs to the infective larval stage required, on average, 121 degree days between 20°C and 30°C. Results provide a basis for predicting variation in the infectivity of eggs in the environment over time in different climates.
authors.affiliation: School of Biological Sciences, University of Bristol, Wooodland Road, Bristol, BS8 1UG, UK.
authors.forename: Dena
authors.initials: D
authors.lastname: Azam
authors.forename: Onyinye M
authors.initials: OM
authors.lastname: Ukpai
authors.forename: Ashraf
authors.initials: A
authors.lastname: Said
authors.forename: Gamal A
authors.initials: GA
authors.lastname: Abd-Allah
authors.forename: Eric Rene
authors.initials: ER
authors.lastname: Morgan
mesh_terms: D000818:Animals; D005260:Female; D007814:Larva / Q000254:growth & development / Q000502:physiology; D010063:Ovum / Q000254:growth & development / Q000502:physiology; D016019:Survival Analysis; D013696:Temperature; D017166:Toxocara canis / Q000254:growth & development / Q000502:physiology*