Possible windborne spread of myxomatosis to England in 1953.

An analysis of the meterological conditions showed that the first outbreaks of myxomatosis in S.E. England in 1953 could have resulted from wind carriage of insects infected with myxoma virus from northern France. South-easterly winds on the night 11-12 August would have carried the insects 120-160 km from the Départements of Nord, Pas de Calais and Somme across the English Channel to near Edenbridge, Kent. The flight would have taken 6.5-8.5 h at wind speeds of 15-22 km h-1. On the night 11-12 August, temperatures increased with height (inversion) up to 500 m; at ground level temperature was around 19 degrees C and at 500 m was 25 degrees C. Insects would have travelled up to the top of the inversion arriving on 12 August as the inversion declined. Two or possibly three generations of infection would have taken place before the disease was seen around the middle of September 1953. The most likely insect was the mosquito Anopheles atroparvus which breeds along the coastal marshes of England and northern France and which has been shown experimentally and in the field to transmit myxoma virus mechanically.