While the world has there eyes and ears on the current Zika virus epidemic, another virus spread by the same mosquito has been seen in huge numbers in the Americas for years.

Dengue fever, the mosquito borne viral disease, continues to expand it’s presence in the Americas and around the globe.

Aedes aegypti/CDC
Aedes aegypti/CDC

In the past 50 years, the incidence of dengue worldwide has increased 30-fold, largely as a consequence of the growth of cities and increased travel.

According to a 2013 WHO report between 1955 and 1959, the number of countries reporting cases of dengue increased from three to eight; in 2012, the geographical distribution of dengue included more than 125 countries.

The World Health Organization (WHO) estimates there may be 50–100 million dengue infections worldwide every year. However,there was 2013 research from the University of Oxford and the Wellcome Trust, using cartographic approaches, estimate there to be 390 million dengue infections per year worldwide.

In the Americas, a trend toward higher dengue fever and dengue hemorrhagic fever incidence rates has been observed during the last decades, with indigenous transmission in almost all countries of the Region. Over the last three decades, a 4.6-fold increase in reported cases was observed in the Americas (~1 million cases during the 80s to 4.7 million during 2000–7), according to a review published in the American Journal of Tropical Medicine and Hygiene in 2012.

The numbers of dengue fever in the Western hemisphere during the first four months of 2016 has topped 1 million, with an actual total of 1,114,856 probable and confirmed cases.

About 72 percent of the cases, or 802,000 were reported from Brazil alone. Following Brazil is Paraguay with 110,000 ( a huge increase compared to last year), Argentina with 57,000 and Colombia reporting 43,000.

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2,326,829 total cases were reported in 2015, while 1,176,529 were seen in all of 2014, 2,386,836 in 2013 (the worst year on record), 1,120,902 in 2012, 1,093,252 in 2011 and 1,663,276 in 2010 (the 1st year Brazil reported more than 1 million cases).

Western hemisphere map Public domain image/ E Pluribus Anthony
Western hemisphere map
Public domain image/ E Pluribus Anthony

Times and things have changed. The number of cases in Brazil in 2016 to date (802,000) is some 250,000 cases higher than the whole region reported in all of 2006 (550,000).

With the introduction of DDT in the 1940s and the approval by PAHO of the Continental Ae. aegypti eradication plan in 1947,  by 1962, 18 continental countries and a number of Caribbean islands had achieved eradication of the mosquito vector.

However, by the 1960s and 1970s, reinfestation, reintroduction and expanding geographic distribution of the mosquito occurred to the point that Texas saw the virus in 1980.

In addition to the illness and deaths, (in 2013, 1,318 deaths were reported), a new study says that dengue is quite expensive–more expensive than cholera or Chagas.

The economic burden that dengue fever imposes on 141 countries and territories around the world where active dengue transmission has been identified comes at an estimated price tag of US$8.9 billion annually, according to Brandeis researchers.