Latest findings by scientists reveal that Zika outbreak in South America was stimulated by the change in weather conditions due to the 2015 El Niño "Godzilla" weather incident.
El Niño Presented Favorable Conditions For The Zika Outbreak
The study conducted by Scientists at the University of Liverpool reveals how climatic conditions can trigger and ignite the outbreak of Zika virus by both its main vectors- Aedes aegypti (the yellow fever mosquito) and Aedes albopictus (the Asian tiger mosquito). An epidemiological model was used by the scientists to infer that the temperature conditions during 2015 El Niño weather incident were highly favorable for the transmission of Zika virus in South America.
El Niño, termed as "Godzilla" due to its large scale global effect, is an unbalanced and complex series of climatic changes affecting the Pacific region and more, every few years. The surface of water tends to get unusually warm, resulting in global impact on weather patterns.
The study published in Proceedings of the National Academy of Sciences noted that the temperature conditions during El Niño were optimal enough to cause an increase in the mosquito biting rate. The period also showed a decrease in the mosquito death rate and the virus incubation period, which is the average time taken by a mosquito to become infectious after biting someone.
South America is considered to be the region with the highest risk of Zika outbreak due to its supportive climate conditions and the presence of large number of virus carrying mosquito vectors.
Vital Aspects Favoring Zika Outbreak
The study lead and an epidemiology and population researcher, Dr. Cyril Caminade stated that Zika virus first entered Brazil as early as 2013, from the Pacific islands or the Southeast Asia. But it was the optimal temperature conditions during 2015 El Niño that favored the virus outbreak two years after its entry into the region.
Apart from El Niño affect, the other factors responsible for Zika outbreak were the weak immune system of the South American people, the risk caused due to travel and business, and the presence of other infections, like dengue, acting as a positive catalyst in the outbreak.
"In addition to El Niño, other critical factors might have played a role in the amplification of the outbreak, such as the non-exposed South American population, the risk posed by travel and trade, the virulence of the Zika virus strain and co-infections with other viruses such as dengue," said Dr. Caminade in a press release.
Early Warning Systems For Zika Outbreak
Since Zika virus is now announced as a major continuing public health challenge by World Health Organization (WHO) and not an international emergency, the epidemiological study can be used to help reduce its ill-effects. Tools can be developed that can help predict the outbreak in future and preventive measures can be taken to minimize the damage caused by it.