Dengue vs. Hepatitis – Part Two

(photo credit: L_J)

"As the race started, Hare sprinted ahead while Tortoise lumbered along at a steady pace.  Hare, seeing that he was far ahead of Tortoise, decided to take a quick nap before resuming the race.  As Hare slept, Tortoise passed him and finished the race.  When Hare awoke he could not believe the situation, to which Tortoise stated, "Slow and steady wins the race."

The Race

The incidence of Dengue fever (DF) is expanding globally, due to the extension of the mosquito vector's habitat, as well as increasing urbanization in endemic regions - DF is now considered endemic in more than 100 countries, many of them with sub-optimal or limited health care infrastructure.  Additionally, DF has at times caused explosive outbreaks regularly leading to infection rates of 40-50% - many of those affected are children. The World Health Organization (WHO) estimates that 2.5 billion people are now at risk of Dengue infection and that there are 50 million infections globally every year.

In comparison, of the viral hepatitis types, it is estimated that 360 million people are chronically infected with Hepatitis B globally and that more than 2 billion people have been infected at some point in their lives.  WHO estimates that 180 million people are currently infected with Hepatitis C globally, of which 130 million are chronic carriers.  Further, WHO assesses that up to 76% of all liver cancer cases are due to chronic HepC infection.  Additionally, there has been a growing trend of concurrent HepB infection and HepC co-infection in HIV-patients, as well as concern around transmission of HepB and HepC among IV drug users.

Much like our Tortoise, Hepatitis infection tends to be an insidious disease that can cause acute debilitation, and more importantly, long-term life-threatening liver disease.  Most individuals chronically infected don't know they carry the virus, yet are still able to transmit the disease.  This, coupled with the prevalence of viral hepatitis in developing countries with limited availability of HepB vaccine and health infrastructure, concurrent HIV infections and lack of sanitation, all lead to a global health crisis.  Dengue, our quick and elusive Hare, is responsible for ever-increasing global morbidity and mortality.  However, its acute onset and progression, requirement for a mosquito vector, limited vector habitat range, and low incidence of progression to the more lethal DHF and DSS forms, make DF less of a pandemic concern.

So, even though our Hare (DF) is characterized by rapid and sometimes explosive outbreaks leading to high morbidity rates, in the end, the high global prevalence and slow, steady, progressive nature of Hepatitis wins this race.