Entomological studies on prevalence of adult and immatures of Aedes ae
gypti along with associated ecological factors have been conducted in
a dengue endemic area of Jalore, Rajasthan from 1992 to 1993. Studies
in two areas; reportedly affected and unaffected revealed more adults
and higher breeding indices in the affected area as compared to the un
affected one. Mosquitoes harbouring dengue antigen were found only in
the affected locality, Presence of dengue antigen in field caught mosq
uitoes in the affected locality was observed mainly during the months
of January to April in both the years. Statistical analysis of data ha
s shown a correlation to be significant between adult house index and
breeding index in the affected area while this: association was found
insignificant in the unaffected locality. Water storage practices of t
he population due to irregular water supply in the affected area is th
e possible cause for a higher vector concentration in the locality, Se
asonality of occurrence of dengue fever patients in a particular perio
d of the year is associated with a relatively higher vector density an
d the presence of infected mosquitoes which is due to favourable tempe
rature, relative humidity, water temperature and pH.