DENGUE VIRUS

GROUP - IV

ORDER - None assigned

FAMILY - Flaviviridae

GENUS - Flavivirus

GENOME - Linear,single-component, single stranded RNA of about 11,000 nucleotides, encoding ten proteins via a polyprotein

GEOGRAPHY - Tropics and subtropics worldwide

HOSTS - Humans, other primates

ASSOCIATED DISEASES - 

Break-bone fever, dengue hemorrhagic fever

TRANSMISSION - Mosquitoes

VACCINE - Several under development, but none available

Source Wikipedia

A rapidly evolving threat An early Chinese text refers to a disease that resembles dengue fever, but the first documented outbreaks of the disease happened in the late eighteenth century, and occurred almost at the same time in Asia, Africa,and the Americas. The virus is transmitted by the yellow fever mosquito, Aedes aegypti. In the 1950s the virus began to appear more frequently and the incidence of dengue fever has increased steadily. This is probably due to changes that occurred after World War II, whice saw many people move from rural areas to urban areas. The mosquito vector is uniquely adapted to urban settings because it breeds in stagnant water, such as rainwater that collects in old tires, unused pots, and other abandoned containers. This mosquito does not tolerate cold climates, and the disease is limited to tropical and subtropical areas of the world. Increased global travel has also contributed to the rise in dengue. It is now the most significant mosquito borne virus in the world, affecting about 390 million peoplea annually and locally high levels of virus infection have given rise to dengue hemorrhagic fever.

There are four different strains of Dengue circulating worldwide, but many areas have one predominant strain. In most people infection is not apparent, but sometimes infection results in fever and very painful joints, and sometimes the disease progresses to a hemomorphic fever, a very serious disease with a mortality rate of nearly 25 percent. The emergence of new strains, which arise in areas where the virus survives in a cycle between non-human primates and rural human populations, combined with the propensity for thev virus  to evolve rapidly  two of the factors making a vaccine difficult. Mosquito control is the only means of prevention.