Climate change key in curbing Zika

Discovered in 1947, the Zi-ka virus remained largely confined to the equatori-al belt in Africa and Asia and ha-rdly any mention was made of it. 

But now, as Dr Fauci, Director of the National Institute of Allergy and Infectious Diseases points out, the “explosive pandemic of Zika virus infection” is “the most recent of four unexpected arrivals” of vector borne diseases (VBDs) in the Americas – the others being Dengue, West Nile Virus and Chikungunya. Alarmed about the virus “spreading explosively,” the WHO declared an international emergency to curb the virus and its potential link to serious birth defects on February 1.  

The first US case of the sexually transmitted Zika opens newly troubling concerns about cur-bing VBDs in a highly globalised world. But the explosive spread of Zika should also serve as a global warning to focus on the debilitating impacts of adverse climatic effects and VBDs amo-ngst the poor and vulnerable communities.

In 2008, Dr Hot-ez, a Tropical Medicine expert, called the spread of VBDs inside the US “neglected infections of poverty” – an ominously apt and globally applicable caution.

Absent a Zika vaccine, effective preventive measures such as use of screens and air conditioning, bed nets sprayed with insecticides, clothing that covers all extremities, eradication of mosquito-breeding water containers are hard to implement in extremely poor communities characterised by unsafe and restricted water supplies, poor hygiene practices and congestion. 

The troubling question is what happens when adverse climatic impacts are added to the calamitous mix of poverty and VBDs? What if increasing global temperatures, extreme changes in precipitation, flooding/inundation, ecosystem damage and disruption are causal factors that contribute to the modern day spread of VBDs amongst the poorest and most vulnerable?

These are not hypothetical questions. The 2014 Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC) identified three pathways by which climate change impacts on human health: 1) Direct impacts, which relate primarily to changes in the frequency of extreme weather including heat,  drought, and heavy rain; 2) Effects mediated through natural systems, for example, disease vectors, water-borne diseases, and air pollution; and 3) Effects heavily mediated by human systems, for example, occupational impacts, under-nutrition, and mental stress. 

Zika is not mentioned, but according to AR5, mosquito borne diseases – malaria and dengue – are the best-studied diseases associated with climate change, due to their widespread occurrence and sensitivity to climatic factors such as temperature, precipitation and humidity.

Rise in temperature The linkage was made clear in the 2013 US Climate Change Adaptation Plan which pointed out that temperature increases can affect the emergence, evolution and geographic ranges of pests, infectious agents and disease vectors. 

A 2015 Montana University study argued that the spread of mosquito borne diseases pose considerable public health risks because increases in ambient temperatures alters the toxicity of insecticides (pyrethroids) used for mosquito control, and also results in expansions of  mosquito populations which cannot be curbed as effectively.  

But what is worst is that poorer communities and countries are generally more vulnerable to negative impacts of climatic extremes and variability. Accor-ding to AR5: “People who are poor and marginalised usually have the least buffer to face even modest climate hazards and suffer most from successive events with little time for recovery”. 

Surprisingly, the heralded 2015 Paris Climate Conference Outcome and its Paris Agreement contain only three references to heath. The “right to health” is proclaimed in the preamble of the Outcome and Agreement, but it is not clear what if any modalities are available to enable the implementation of this “right“; and how countries will respond to climate induced health threats, including VBDs? 

The only other reference to health is found in a single paragraph in a section dealing with enhanced action prior to 2020 which reads: “Recognises the social, economic and environmental value of voluntary mitigation actions and their co-benefits for adaptation, health and sustainable development”. But again, it is unclear how this will translate into concrete and practical global action on climate induced health threats? The 2016 WHO declaration should spark more coordinated global responses to climate-associated VBDs that rob the world of its future generation-poor lives matter.

(Anilla Cherian is the author of “Energy and Global Climate Change: Bridging the Sustainable Development Divide”)

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