In Colombia this year, 115 deaths from dengue fever have been reported by the country’s National Health Institute. And registered cases of the disease from July to September have numbered 120,000, over twice the expected average for the year.
The significant rise in infections has been caused by the higher temperatures experienced this year. The hotter weather is the result of the El Nino phenomenon, which affects global weather every three to eight years. El Nino brings warmer ocean and atmospheric conditions across the Pacific, leading to more extreme weather patterns globally. This year’s El Nino effect has been one of the strongest in history.
The rise in temperatures has meant people in Colombia are more vulnerable to dengue fever. The disease is spread by the bite of infected female ‘Aedes aegypti’ mosquitoes. These have been breeding in more areas across Colombia with the hotter climate. Generally, the mosquitoes reproduce in altitudes up to 1800 metres above sea level and in temperatures between 24 and 28 degrees, but they can also be found above 1800 metres.
Dengue fever causes severe flu-like symptoms, but in one fifth of cases the disease can be more serious. Delayed treatment or misdiagnosis can be fatal and death can also result through a complication called dengue haemorrhagic fever. Though most of the 50 million infections worldwide are in Africa and south-east Asia, the number of cases is growing across the Caribbean, Central and South America. From January to July this year, over a million cases of dengue fever have been registered by the Pan American Health Organisation.
In Asian countries, public campaigns spread awareness of the disease and encourage people to keep communal spaces tidy. This is because the ‘Aedes aegypti’ mosquitoes breed in man-made containers, such as old tyres and metal drums. In Colombia, there is poor awareness about the environmental conditions which prove ideal for the spread of the mosquitoes. Poor rainwater drainage and sanitation leave pools of water exposed and garbage often lies around gathering water. Even small waste items, such as discarded food containers or jars, can offer breeding grounds for the mosquitoes.
Nearly two thirds of all Colombia’s 1,102 municipalities suffer from drainage, sewage and garbage collection problems. And without education about the dangers, cases of dengue are likely to remain high this year. Since no vaccine is currently available, governments across South America will need to be more aware of the growing threat posed by higher temperatures and encourage the kind of clear-ups around houses and public spaces which already take place in the Far East.