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Climate change and rising global dengue risks

Dan Steinbock | Published: August 19, 2019 21:16:09 | Updated: August 28, 2019 20:41:32


-Star Mail photo

In mid-July, Philippines health authorities declared a "national dengue alert." In early August, the Department of Health declared a National Dengue Epidemic. By now, the number of cases has soared to 170,000, with 720 deaths; that's 100 per cent higher relative to 2018, despite a delayed rainy season. The most affected age group among dengue deaths is 5-9 years.

The dengue outbreak in the Philippines and several other South and Southeast Asian countries is now international headline news. But how did dengue become "endemic" to these countries?

THE CONVENTIONAL DENGUE NARRATIVE: By the 2010s, dengue caused the greatest human disease burden of any arbovirus - that is, viruses that are transmitted by mosquitoes, ticks, or other arthropods, including yellow fever - with estimated 10,000 deaths and 100 million symptomatic infections per year in over 125 countries.

Historically, the first epidemic instances of dengue occurred in Asia, Africa and North America in the late 18th century. The ecological disruption in Southeast Asia and the Pacific during and after World War II fostered conditions for increased transmission of mosquito-borne diseases.

The first recorded dengue hemorrhagic fever (DHF) epidemic occurred in Manila, in the early 1950s, but within 20 years the disease in epidemic form spread throughout Southeast Asia.

By the mid-1970s, dengue was the leading cause of hospitalisation and death among children in the region, while epidemics intensified in the Pacific and the Americas. Since the 1980s and 1990s, epidemic dengue transmission has intensified further, with a global resurgence of dengue fever.  In this view, the Philippine dengue epidemic is the net effect of environmental conditions (last July was the warmest in recorded history), vaccination debacle (Dengvaxia mess, corruption), extreme weather (high precipitation), living conditions (high urban density), and socio-economic vulnerabilities (low living standards, high income polarisation, weak public-health system).

Yet, medical studies presume that dengue is "endemic" to certain climate areas, even though it has been purposefully exploited ever since the post-war era. The Philippines has a special role in this dark history of experimentation on unwitting human subjects. US bio-tests began in the Philippines in 1906, when Richard P. Strong, then head of the Philippine Biological Laboratory, inoculated 24 inmates of Manila's Bilibid Prison with a cholera vaccine that had been contaminated with plague causing 13 fatalities.

THE COVERT DENGUE HISTORY: After World War II, the United States quietly augmented domestic efforts by recruiting major Nazi and Japanese bio-warfare scientists. As weaponisation activities began with disease vectors in the early '50s, the focus was on plague-fleas, mosquitoes, and yellow fever. During tests in Utah, Georgia and Florida, hundreds of thousands of fleas and (yellow fever) mosquitoes were dispersed, according to US Army studies.

Until the early '70s, US programme stockpiled dangerous bioagents and pursued research on many more. In 1972 the Biological Weapons Convention (BWC) banned the "offensive" use of biological and toxin weapons, yet the treaty, which suffers from verification and compliance issues, left the door open for "defensive" bio-warfare and "research" in major powers.

Historically, dengue fever had been the focus on US Army and CIA biological warfare researchers for more than half a century. US Army's Biological Warfare facility at Fort Dietrick, Maryland, has experimented with dengue fever, as verified by US historians and congressional committees since the 70s. By 1981, Cuba struggled amid an epidemic of hemorrhagic dengue fever, although it did not have a history of severe dengue outbreaks.

During the Cold War, when biological agents were produced in industrial scale by the Soviet Union and the US, the threat of the mutually assured destruction constrained risks. After the Cold War, the Nunn-Lugar Cooperative Threat Reduction Program (CTRP) presumably aimed to keep the former Soviet Union's nuclear and chemical infrastructure from rogue nations and terrorists. Yet, in 1996 Congress expanded the programme internationally.

Branching from the Nunn-Lugar programme, bio-labs are funded by the Defense Threat Reduction Agency (DTRA) under a multibillion dollar military Cooperative Biological Engagement Program (CBEP). The CBEP labs are located in 25 countries, including in Eastern Europe (e.g., Georgia and Ukraine), the Middle East, Africa and Southeast Asia - and the Philippines.

Critics claim that some of these locations have seen outbreaks of tropical diseases, which are not endemic to the area. After 2015, sand flies, which can be found in Philippines (and were tested on humans in US in early '70s), have infested areas in Tbilisi, Georgia. In turn, outbreaks of tropical diseases, such as dengue, have become more severe.

Until recently, there had been no dengue outbreak in the US since the 1930s. Presumably, dengue had been eradicated, despite global increases in incidence and severity, and immigration. But in 2009, several residents in Key West, Florida showed infection. According to a study by the Centers for Disease Control (CDC), the infection rate in the area was 5 to 8 per cent. Mosquitoes known to spread dengue fever were found in more than half of US states.

According to CIA documents and the 1975 Congressional committee, three sites in Florida, Key West, Panama City and Avon Park, and in central Florida, had been used for experiments with mosquito-borne dengue fever and other biological agents.

DENGUE SCOPE, COSTS, SEVERITY WILL ESCALATE: Thanks to global warming, the dengue challenge is likely to get worse. Risks from some vector-borne diseases, such as malaria and dengue fever, are projected to increase with warming from 1.5°C to 2°C. That, in turn, will cause an increase in the number of mosquitoes, a larger geographic range, and more individuals will be at risk of dengue fever.

In a recent study, the total annual global cost of dengue illness was estimated at $8-9 billion (with upside estimates at $20 billion). Rising temperatures imply that dengue will intensify in "already endemic areas." By 2050, much of southeastern US will become suitable for dengue, inland areas of Australia, many of the larger cities in coastal China and Japan, and particularly in southern Africa. Globally some 2.3 billion more people will be at risk of dengue in 2080 compared to 2015, bringing the total population at risk to over 6.1 (high estimate 6.9) billion, or 60 per cent of the world's population.

The role of covert attempts in viral outbreaks is hard to assess, but the concern is rising. A new Pentagon programme called "Insect Allies," which is funded by the Defense Advanced Research Projects Agency (DARPA) and relies on gene editing, wants to infect insects with modified viruses, presumably to make US crops more resilient. Some international scientists believe such initiatives can easily be exploited as new bio-weapon systems programmes, which violate the Biological Weapons Convention.

After the Cold War, US has dominated biological defence and research. With rising climate risks and geopolitical tensions, no single country should have monopoly over global biological agents in the 21st century, however. Potential conflictss of self-interest are obvious, tragic and potentially existential.

Like "dual-use" technologies that can be used for both peaceful and military objectives, biological agents can serve as potential antidotes and weapons. What we truly need is multipolar cooperation among the major advanced economies and largest emerging powers. Only such checks can constrain existential biological risks to vast urban populations in the future.

[This commentary is based on Dr Steinbock's fully-referenced research note on the dengue outbreak in the Philippines,climate change and rising global dengue risks.]

Dr. Dan Steinbock is the founder of Difference Group and has served at India, China and America Institute (US), Shanghai Institute for International Studies (China) and EU Center (Singapore).

The original commentary was published by The Manila Times on August 18, 2019

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