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Seasonal and Circadian Dynamics

Overview

In temperate climates, in detail the seasonal activity will include the season from April to October in the Old World. Whereas in tropical and neotropical climates, sand fly activity is registered the whole year.

The circadian activity of the adult fly is crepuscular and nocturnal. Many species bite most actively immediately after sunset, but others have been observed to bite after midnight. But this time peak is not universal. It is probable that the fall in temperature and the rise in humidity as the sun goes down are the triggers for this activity.

Depending on the area, and especially the time one hour before until one hour after sunset is the main feeding time. Noli (1999) is extending this time period of activity over the whole night. During day cool and humid resting places are sought (Killick-Kendrick and Killick-Kendrick, 1999).

Numerous studies have been concentrating on daily as well as seasonal activity of phlebotomines. Different methods of collection and different time and place have been practiced.
Variations in adult emergence and remaining over the season are according to differences between years and climate, notably temperature at varying altitudes. For the seasonal activity, between one and two peaks of population can be observed in phlebotomines.
Taking into account that various phlebotomine species have been classified as reported and suggested vectors of leishmaniosis, seasonal activity and thus risk of transmission stretches between spring and autumn.
Generally, depending on the area, temperature, humidity and diverse other environmental factors, sand fly activity can vary to a great extent and thus making general considerations in times very difficult.

   

References

  • Killick-Kendrick, R., and M. Killick-Kendrick: Biology of sand fly vectors of Mediterranean canine leishmaniasis. In: Killick-Kendrick, R. (ed.): Canine leishmaniasis: an update. Proc. Int. Can. Leishm. Forum, Barcelona, Spain, 1999, Intervet Int., Boxmeer, The Netherlands, pp 26-31, 1999
  • Noli, C.: Leishmaniose des Hundes. Waltham Focus 9, 16-24, 1999

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