Until today, no successful vaccine for dengue fever has been
developed. According to the World Health Organization (WHO), dengue
fever and DHF are among the most rapidly increasing insect-borne
illnesses today. Several factors are believed to contribute to the wide
spread of dengue fever. Inadequate water and waste treatment facilities,
along with insufficient pest control measures, promote the rapid
increase of mosquito populations in certain areas. In addition,
dwindling public health resources cannot keep up with the needs of
growing urban populations that are susceptible to infection.
What is the topic of the above paragraph ?
A Viral disease carried by mosquito
B Why the spread of dengue fever cannot be stopped
C The importance of pest control measures
D Inadequate water and waste treatment facilities
E WHO program for eradicating dengue fever