I spent the month of August living and working with our sisters in Argentina. Of course it was winter there, and when I arrived at the beginning of the month, it was cold. Soon, however, the weather changed and it became unseasonably warm. The sisters told me that their winters have become much warmer in recent years and that there has not been enough rain. With the warm weather comes mosquitos and the threat of dengue fever and malaria. The shorter winters and longer periods of warm weather mean that the people have a longer exposure to these disease bearing insects. Earlier this year, dengue fever reached epidemic proportions in Argentina with at least 8000 reported cases.
It turns out that during my stay in Argentina I experienced an aspect of climate change that is rarely discussed – the relationship between climate change and health.
According to the World Health Organization global climate change poses grave risks to human population health. Throughout Latin America and the Caribbean there have already been alterations in the geographic range (latitude and altitude) and seasonality of certain infectious tropical diseases.
One of these is Dengue (or “breakbone”) fever, a disease that is characterized by high fever, rash, and severe headache with aching bones, joints, and muscles. Dengue and its deadly complications, dengue hemorrhagic fever and dengue shock syndrome, have increased over the past several decades. Global warming has substantially increased the number of people at risk of dengue epidemics, as warmer temperatures and changing rainfall conditions expand both the area suitable for mosquitoes and the length of the dengue transmission season in temperate areas.
Currently, dengue fever and its complications cause an estimated 50 to 100 million infections, a half-million hospitalizations, and 22,000 deaths annually in more than 100 countries, including parts of South America, Central America, the Caribbean, India, Southeast Asia, and Africa. By 2085, an estimated 5.2 billion people—3 billion additional people worldwide—are projected to be at risk for dengue because of climate change–induced increases in humidity that contribute to increased mosquito presence. Already, the specific types of mosquitoes that can transmit dengue fever have become established in a swath of at least 28 states and the District of Columbia, and across the south and mid-Atlantic regions of the United States and there were 4000 cases of the disease reported to the Centers for Disease Control between 1995 and 2005.
Another disease that is on the move is Leishmaniasis, sometimes known as Jericho Buttons. Until recent years found in parts of the tropics, subtropics and southern Europe, leishmanaias is a parasitic disease that is transmitted by the bite an infected sand fly. Now, cases of the disease are being reported among mountain dwellers in the Andes in Peru. The disease causes skin sores, which may develop a raised edge and central crater, causing the sores to look much like a volcano. These sores take a long time to heal and often leave scars. In the more severe forms of the disease, killer parasite migrate to the internal organs, such as the liver, spleen and bone marrow and cause fever, weight loss and swelling of the spleen and liver. If left untreated, severe cases may result in death.
Personally, I find the threat of these diseases becoming prevalent in the area where I live a great motivator for taking positive steps toward reducing my contribution to global warming. How about you?