Score Plus

The number of people diagnosed with dengue fever (which is contracted from the bite of an infected mosquito) in North India this year is twice the number diagnosed last year. The authorities have concluded that measures to control the mosquito population have failed in this region.

All of the following, if true, would cast doubt on the authorities’ conclusion except

A. more cases are now reported because of increases in administrative efficiency
B. a very high proportion of the cases were in people who had recently returned from neighboring countries
C. an effective diagnostic test was introduced about nine months ago
D. the disease is prevalent only in some industrialized areas which have shown a dramatic increase in population due to migration
E. the incidence (number of cases per thousand) of malaria, also contracted from mosquito bites, has increased