S.Charandeep Singh
Recall the masked faces of our family and friends during last summer and we pray we should not be witnessing the same this summer. But can we avoid that, would be a million dollar question to answer? It all started with the reporting of mystery fever amongst few and later after sampling/testing emergence of new virus was reported. It was reported that this virus was mosquito-borne and the vector was Aedes aegypti. Primarily the signal was to remain away from the sting of the mosquito as it was never known which mosquito would be creating jingles in our ears and where would that sting lead us to either Malaria,Dengue,Chickenguniya or Zika virus or any other mystery fever. The World Health Organisation had declared an international emergency last year over the explosive spread of Zika virus- the mosquito-borne disease which has been linked to birth defects in the Americans and also the Guillain-Barres syndrome. WHO had estimated that there could be up to 4 million cases of Zika in America this year?
Historically, Zika virus was not a human disease causing organism. It was first discovered in monkeys in the forests of Uganda from where it got transmitted to the local population in 1952. Outbreaks of Zika virus disease have been recorded in Africa, the Americas, Asia and the Pacific. In 2007 it was reported in Yap (Federated States of Micronesia) and in 2013 it was found in French Polynesia. As per the reports of WHO, in the recent past major countries have reported outbreak of Zika virus. These are Brazil, Barbados, Bolivia, Columbia, the Dominic republic, Equador, Elsalvador, French Guiana, Guatemala, Guadeloupe, Guyana, Haiti, Hondur as, Martini que, Mexico, Panama, Paraguay, Puerto Rico, Saint Martin, sriname and Venezuela.
Zika virus is spread by Aedes mosquitoes, the same type that spreads dengue and Chikungunya virus. Unlike malaria these mosquitoes are active during the day. Deaths in these cases are rare and only one in five people infected are likely to develop symptoms that normally last for 2-7 days. Mild fever, conjunctivitis, headache, joint pains are some of the symptoms. No specific treatment or vaccine is available yet the patients are advised to take rest and take plenty of drinking water. But the biggest concern is its impact on the foetus as it can easily pass through the placenta. It causes a condition in the foetus known as microcephaly in which the development of the brain gets stunted. So pregnant women are advised to remain away from the places where there is more prevalence of such organism.
In 2014 public health emergency was also declared for the Ebola outbreak in West Africa, which killed more than 11000 people. Declaring an emergency for such serious public health matter has been taken as an SOS signal for pulling up men and machinery and for taking measures to control the disease and put a stop to the outbreak and also a signal for more progressive research through the use of prevalent samples of the disease causing organism for better treatment and vaccines.
To control the virus WHO has formed Zika Strategic Response Framework which outlines four main objectives i.e. detection, controlling mosquitoes, care and support; and fast track research. These are to support national Governments and the communities in preventing and managing Zika and its varied complications. Detection encompasses development, strengthening and implementing surveillance to guide the response. Adverse health conditions are prevented through controlling mosquitoes. Commmunity engagement and risk communication, strengthening health and social systems to provide service and support to populations and communities makes the care and support of the framework and research for public health guidance and mosquito control have been contemplated as integral framework since economic burden of the countries have increased. In 2016 3.5 billion dollars was the estimated global cost for Zika virus and on the human resource front, 29.95/case DALY (disability-adjusted life year, a measure of overall disease burden and expressed as the number of years lost due to ill-health, disability or early death) due to microcephaly and 1.25/case DALY due to Guillain-Barres syndrome have been reported by the WHO.
We have seen in the recent past that once there are reported cases of Zika virus our reputed national laboratories look for procurement of test kits and while we remain in the procurement process spread of the diseases had already caused havoc in the countries. As per the reports of WHO 122.1 million dollars would be required for executing the plan w.e.f July2016 to Dec.2017 in which 60 strategic partners which had already got infested in the past shall be collaborating.
But why is it that we have not yet been able to contain the emergence of such disease causing organism. The answer is the denial mode i.e. we have failed to adapt to the changing nature of Aedes aegypti as normally the mosquito breeds in clean stagnant water but intermittent rains linked with climate change has adapted the mosquito to breed in dirty water as per a study published in the Indian journal of Medical Research in 2015, however, The National Vector Borne disease control Programme’s 2016 Urban Vector-Borne Disease scheme did not consider dirty water as its breeding area which indirectly leaves one breeding ground i.e. potential disease spreading area.
However, innovative methods are being developed across the globe to tame the mosquitoes. National University of Singapore, National Technological University, Singapore, and the Indian Institute of Bombay have created a web- and mobile-based application for surveillance. This MO-Buzz application encompasses predictive surveillance, civil engagement and health communication. Researchers have been actively developing genetically modified (GM) mosquitoes to control the population of vectors.GM mosquitoes are created by injecting the eggs with modified DNA. The GM male mosquitoes are released to mate with the female mosquitoes which have short span progeny. A British company, Oxitec, had released GM mosquitoes in Brazil which had given positive results with 82 percent reduction of mosquitoes in eight months.
Another vector controlling method is the use of Wolbachia bacterium. This bacterium has the capacity to reduce the growth of the disease causing organism in the body of Aedes aegypti. Both male and female bacteria infected mosquitoes are released in the environment and when they mate with the normal bacteria they seize reproduction. Another vector control method under research is the use of parasitic fungus Metarhizium brunneum that has the potential to control the Aedes population.
An Indian invention, by a Kerala resident Mathews K Mathews, called Hawker, a mosquito and fly trapper which uses smell from the septic tank to attract and sunlight to kill the mosquito is another local innovation to be added to the national and the international interventions for vector control.
But these measures need to be put to multiple trials before these can actually be put to use as regards GM mosquitoes national Governments are unwilling to use them due to possibility of mutations that they may initiate in other organisms which may be more harmful.
Therefore, it is important to tame the mosquitoes to control vector borne diseases and in that regard the National health policy 2017 that seeks universal health coverage and increased secondary and tertiary healthcare services needs to keep focus on the aspect of the emergence of the new disease causing organism and the old mutated disease causing organism before going for the “strategic purchasing” as envisaged in the National Health policy so that the public at large can avail the benefits at an appropriate time as part of the National health security.
(The author is a KAS officer and an alumni of National University of Singapore)
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