00000000More recently(42), ten new isolates of DEN-2 virus were obtained in 1985, 1986 and 1987 from a savannah area, from sylvatic vectors (one from A. Africanus, six from A. luteocphalus) as well as from domestic ones (three from A. aegypti). No human repercussion was noticed during this period, but this is evidence that the virus is still present in the country.

00000000 In 1985, one single strain of DEN-1 was isolated from domestic A. aegypti caught in a savannah village(42).

Senegal

00000000Three types of DEN virus have been isolated in Senegal and observations have varied according to the virus type involved.

Dengue 1
00000000In the village of Bandia, 80 km south-east of Dakar, the population was under surveillance for arbovirus circulation and sera were collected from every febrile patient. In October 1979 two strains of DEN-1 virus were isolated from the sera of Senegalese patients with very mild diseases. At the same time two more cases were serologically diagnosed in Europeans who slept in the bush in the same area; these were more severe diseases, but without haemorrhagic or shock syndromes. Serological surveillance was maintained in this area from 1980 to 1982, when 21.5 per cent of children had DEN-1 antibodies but all the results were negative for sera of children born after the outbreak.

00000000 Sera were also available from the region of Kaolack (120 km east-south-east of Bandia), where children were under surveillance for another purpose and sera were collected every three months between 1978 and 1983. Twenty-one children were serologically tested for DEN-1 antigen and nine showed a seroconversion between September 1979 and January 1980 (unpublished data); five of these were demonstrated by the CF test and four by the ELISA test.

00000000 In 1981 a small outbreak of yellow fever occurred around the small town of Mekhe (75 km north-east of Bandia); a high prevalence of DEN-1 antibodies was found in the sera of two year old children. The same observations were made in 1982 (unpublished data) during a chikungunya outbreak in the area of Touba (130 km east of Bandia).