Fundació Roger Torné second Conferences held on November 11th and 12th on the subject “Global warming and children’s health” under Dr Jordi Sunyer’s scientific direction, counted on important lecturers’ participation such as Dr Edward B. Hayes* whose lecture “Health and global warming on tropical countries”, allowed us understand in a simple and educational way, the existent complexity between global warming effects and human health.
During his lecture, Dr Hayes outlined the existence of an important net of interrelations among global warming, human behavior and different ways of life when explaining the factors that have an influence on diseases transmitted by vectors. No doubt the incorporation of other variables to the analysis of global warming effects on human health does not make this relationship invalid, on the contrary, on one side it enriches its research and, on the other, it makes it more complex. Nevertheless such a complex matrix has a difficult solution.
Likewise, Dr Hayes stated that transmission diseases through vectors such as Dengue or West Nile viruses can have a very different incidence regarding the different countries, depending on three factors: transmission vector abundance (mosquito Aedes aegypti in dengue’s case), the abundance of reservoirs (the agents through which one mosquito or tick can get the virus or the germ which causes the diseases on mankind, such as birds and rodents) and finally, human behavior itself (ways of living, measures of prevention, etc.) Particularly Dr Hayes set as an example the appearance of a Dengue outbreak in Nuevo Laredo (México) while Laredo`s partner city in Texas was not affected. After carrying out a research and noticing that they were two border cities with identical climate and, thus, without the existence of differences from a climatic point of view, researches concluded that this outbreak appearance in Mexico and not in Texas was due to human behavior itself, for using conditioned air at home.
All in all, Dr Hayes pointed out that global warming effects such rise in temperature for example, affected arbovirals diseases since it provoked an increase in the transmission index. Nevertheless he also analyzed its contrast; a temperature raise could also diminish these diseases transmission vector survival, namely the mosquito. So it is difficult to predict the final balance.
Because of the many factors that have an influence on arbovirals diseases transmission, sometimes the researches carried out on this subject give away opposed results but not wrong ones. To be precise, Dr Hayes showed us how he and his colleagues in Center of Diseases Control (CDC) in the United States analyzed separately Katrina Hurricane effect regarding the incidence on West Nile virus disease which was detected on the area. Dr Hayes and his staff concluded that there was no clear correlation between these factors. Nevertheless, the group of scientists belonging to the University of Tulane stated that it did.
It is clear that global warming affects vector diseases transmission. But the degree they can affect their increase or decrease depends on the combination of many factors. In the case of developed countries, the effects can be mitigated by prevention. Nevertheless, regarding developing countries, the shortage of resources for public health could damage the capacity of reaction in front of an increase of risk. Dr Hayes was assertive when stating that the long term effects can be mitigated depending on our action.
What can we do to prevent the transmission of these diseases so that they do not increase because of global warming or human behavior?
Dr Hayes proposed to take action on four areas. First of all, implementing monitoring systems that allow detect the appearance and the changes in the pathogenic. Secondly, developing and supplying with vaccines. Third, to improve the provision of sanitation nets. And fourth, to take action on public health services in order to foment a suitable health.
Finally, Dr Hayes gave us one useful receipt that, despite being simple, it is also important in order to cope with global warming effects on health: our efforts must be focused on actions we know they are working.
*Dr Edward B. Hayes obtained his degree in Tufs University Scholl of Medice of Boston (USA). He carried out his residency on pediatrics in the Maine Medical Center and he studied Epidemiology in the centre for Disease Control and Prevention (CDC) in the United States. During his stay on CDC he worked on infectious diseases, environmental health and in the application of epidemiologics data in order to prepare the public health policies. He has directed researches on vigilance and epidemiology regarding arbovirals diseases in CDC. He is author and co-author of several medical texts and of more than 40 articles in medicine magazines. He is working as a researcher in the Centre de Recerca de Salut Internacional in Barcelona (CRESIB).