As the outbreak of dengue assumes life-threatening proportions, India must not only treat the symptoms of this virus, but also address the root cause contributing to its spread — climate change
Over the past one month, the number of dengue cases have shot up alarmingly, with a maximum number of cases being reported in the national capital. The tragic deaths of a seven-year old boy, Avinash and six-year old Aman due to dengue has forced the Delhi Government to acknowledge the gravity of the situation.
Consequently, the Delhi Government has cancelled the leaves of doctors and stringent measures are being initiated against the hospitals that are negligent in handling dengue cases. But are these measures sufficient enough drive away the dread diseaseIJ Apparently not, because India suffers from the outbreak of dengue every year and undergoes loss of life that is completely avoidable.
As hospitals struggle to cope with the deadly virus that is spiraling out of control, it is crucial for the Government to break the the annual cycle of the occurrence of this disease. Usual preventive measures like creating awareness about the disease and eliminating mosquito breeding grounds are no longer sufficient to ensure comprehensive eradication of dengue.
Globally, 50 to 100 million cases of dengue are reported each year with over 2.5 billion people at risk and given the fact that the disease is untreatable, it makes it all the more dangerous. According to a research conducted by the Environmental Health Perspectives, a journal under the aegis of the United States Department of Health and Human Services, climate change is increasingly playing a significant role in the pattern of occurrence of dengue and it is now considered to be one of the major causes for its repeated outbreak across the world.
Besides adversely impacting the environment, climate change has the potential to contribute to the deterioration of human health by providing amicable environment of higher temperatures for vector borne diseases such as dengue.
Changing climatic conditions can have a considerable influence on the population dynamics of mosquitoes. According to a research by Rueda et al 1990, immature Ae albopictus the species development rates showed an increase with incubation temperatures of 34 degree Celcius, whereas cooler temperatures proved to be detrimental for the survival and growth of the same.
Changes in climatic conditions has a cascading effect on the spatial and temporal dynamics of dengue virus ecology by potentially increasing vector ranges, lengthening the duration of vector activity, and increasing the mosquitoes infectious period by shortening the extrinsic incubation period.
EIP is the time required for the dengue virus to become transmissible to another host after initial infection of a mosquito. The suitable increase in ambient temperatures helps the mosquito to breed faster and transmit the virus rapidly due to favourable influence on vector development rates, mortality and behavior. This in turn assists in viral replication.
On the other hand, variability in precipitation, influences the habitat availability for the larvae and pupae of the specific mosquito carrier species. Climbing temperatures also pose a challenge for the mitigation measures that seek to limit the spread of the virus.
Government’s action plan to rein in dengue must earnestly begin with the urban areas, which report maximum number of dengue cases. Urban concrete structures tend to reflect heat and relentless demand for energy turn the urban areas into polluted heat islands that become high temperature traps.
These areas eventually become favourable fast-track breeding grounds for the virus. Since there is no curative treatment, targeted environmental and ecosystem management is increasingly relevant in order to quell the rise of the disease.
The Government can make use of the available scientific knowledge about vector ecology and disease epidemiology in correlation with environmental factors especially climate change to design improved programmes for disease management and community action that can help counter dengue.
In addition, predictive computer models can help determine accurately a ‘threshold’ limit for epidemic risk in a each locale, this can pre-empt disease outbreak and, therefore, enable deployment of preventive measures.
As disease proportions increase globally, countries are relying on cutting edge technology in order to wipe out dengue. Satellite imagery is increasingly being relied upon to map the high-risk dengue prone locations.
These images help identify environmental and other causes for dengue, besides providing accurate information on imminence of a possible next outbreak. Furthermore, any effort by the Government will be incomplete without people’s participation. The authorities combatting dengue must incorporate an effective ‘bottom-up’ community participation strategy.
As the disease assumes life-threatening proportions, India must not treat symptoms of the virus such as mosquito breeding, but must address the root cause of climate change that is helping vector borne diseases to wreak havoc on humanity every year.