Recent outbreaks
Main articles: 2005 dengue outbreak in Singapore, 2006 dengue outbreak in India, 2006 dengue outbreak in Pakistan, and 2009 Bolivian dengue fever epidemic
An outbreak of dengue fever was declared in Cairns, located in the tropical north of Queensland, Australia on 1 December 2008. As of 3 March 2009 there were 503 confirmed cases of dengue fever, in a residential population of 152,137. Outbreaks were subsequently declared the neighbouring cities and towns of Townsville (outbreak declared 5 January 2009), Port Douglas (6 February 2009), Yarrabah (19 February 2009), Injinoo (24 February 2009), Innisfail (27 February 2009) and Rockhampton (10 March 2009). There have been occurrences of dengue types one, two, three, and four in the region. On March 4, 2009, Queensland Health had confirmed an elderly woman had died from dengue fever in Cairns, in the first fatality since the epidemic began last year. The statement said that although the woman had other health problems, she tested positive for dengue and the disease probably contributed to her death.
An epidemic broke out in Bolivia in early 2009, in which 18 people have died and 31,000 infected.
In 2009, in Argentina, a dengue outbreak was declared the northern provinces of Chaco, Catamarca, Salta, Jujuy, and Corrientes, with over 9673 cases reported as of April 11, 2009 by the Health Ministry . Some travelers from the affected zones have spread the fever as far south as Buenos Aires . Major efforts to control the epidemic in Argentina are focused on preventing its vector (the Aedes mosquitoes) from reproducing. This is addressed by asking people to dry out all possible water reservoirs from where mosquitoes could proliferate (which is, in other countries, known as "descacharrado"). There have also been information campaigns concerning prevention of the dengue fever; and the government is fumigating with insecticide in order to control the mosquito population.
The first cases of dengue fever have recently been reported on the island nation of Mauritius in the Indian Ocean. One of the South Asian countries still suffering highly from this problem is Sri Lanka.
HOT SPOT COUNRTIES
It occurs widely in the tropics, including northern Argentina, northern
Australia, Bangladesh, Barbados, Bolivia, Belize, Brazil, Cambodia,
Colombia, Costa Rica, Cuba, Dominican Republic, French Polynesia,
Guadeloupe, El Salvador, Guatemala, Guyana, Haiti, Honduras, India,
Indonesia, Jamaica, Laos, Malaysia, Melanesia, Mexico, Micronesia,
Nicaragua, Pakistan, Panama, Paraguay, Philippines, Puerto Rico, Samoa,
Western Saudi Arabia, Singapore, Sri Lanka, Suriname, Taiwan, Thailand,
Trinidad, Venezuela and Vietnam, and increasingly in southern China.
Virus classification
Group: Group IV ((+)ssRNA)
Family: Flaviviridae
Genus: Flavivirus
Species: Dengue virus
Vaccine development
There is no tested and approved vaccine for the dengue flavivirus.
There are many ongoing vaccine development programs. Among them is the
Pediatric Dengue Vaccine Initiative set up in 2003 with the aim of
accelerating the development and introduction of dengue vaccine(s) that
are affordable and accessible to poor children in endemic countries.
Thai researchers are testing a dengue fever vaccine on 3,000–5,000
human volunteers after having successfully conducted tests on animals
and a small group of human volunteers. A number of other vaccine
candidates are entering phase I or II testing. As of July 2010, the
National Institutes of Health reported on their ClinicalTrials.Gov Web
site that there were 19 vaccines undergoing testing or recruiting for
participants. Because exposure to one of dengue's 4 serotypes provides
no immunity against infection by the other types, and may make the
patient susceptible to more severe disease symptoms, testing vaccines
must be performed carefully, and usually not in areas where the disease
is endemic for fear that even attenuated virus vaccines may cause
severe reactions.
In 1998, scientists from the Queensland Institute of Medical Research
(QIMR) in Australia and Vietnam's Ministry of Health introduced a
scheme that encouraged children to place a water bug, the crustacean
Mesocyclops, in water tanks and discarded containers where the Aedes
aegypti mosquito was known to thrive. This method is viewed as being
more cost-effective and more environmentally friendly than pesticides,
though not as effective, and requires the continuing participation of
the community.
Even though this method of mosquito control was successful in rural
provinces, not much is known about how effective it could be if applied
to cities and urban areas. The Mesocyclops can survive and breed in
large water containers but would not be able to do so in small
containers that most urban dwellers have in their homes. Also,
Mesocyclops are hosts for the guinea worm, a pathogen that causes a
parasite infection, and so this method of mosquito control cannot be
used in countries that are still susceptible to the guinea worm. The
biggest dilemma with Mesocyclops is that its success depends on the
participation of the community. This idea of a possible parasite-
bearing creature in household water containers dissuades people from
continuing the process of inoculation and, without the support and work
of everyone living in the city, this method will not be successful.
