Zika Virus: From Past to Present

By Ava Torjani

By now, you’ve probably heard of Zika—a virus that has gained substantial attention due to its recent rapid spread worldwide and the increasingly concerning findings regarding its method of transmission and fatal consequences. We have been warned about its symptoms, its pandemic potential, and its incurability at this point in time. But perhaps what is truly worrying is the sudden and unpredictable nature of this dangerous virus. You may be wondering, where did Zika even come from? How did it become so dangerous? Below, a description of the key developments and discoveries of the Zika virus is given from its conception till today.

Timeline       

  • 1947: The Zika virus is first discovered in a Rhesus monkey and named after the Zika Forest of Uganda.
  • 1948: Researchers identify the mosquito Aedes africanus as the vector for the Zika virus.

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  • 1950s: Humans are reported to be infected with the Zika virus in Uganda and Tanzania. Meanwhile, two new strains of the virus are also discovered in the Zika forest.

Different strains of the Zika virus have different genetic make-ups, which leads to differences among their infectious abilities and levels of threat to us, just like influenza.

  • 1964: A researcher working in Uganda who had been infected with the Zika virus experienced a mild illness accompanied by a pink, non-itchy rash. This is the first case of a human illness associated with the virus.
  • Mid 1960s-1980s: There is an increase in the number of reported human cases as the Zika virus spreads across mid-Africa and certain regions in Asia including Malaysia, India, and Pakistan. Nonetheless, the disease is not given much attention since the reported symptoms are mild and do not require extensive medical care.
  • 2007: The first outbreak of the Zika virus occurs in the Island of Yap located in the Pacific Ocean, manifested by a disconcerting increase in symptoms including joint pain, rashes, and eye inflammation.

It is interesting to note that this increase may be due to not only the virus itself, but also the lack of accurate diagnosis. This is because the Zika infection, Dengue fever, and chikungunya virus share the same vector (mosquito) and have very similar symptoms. Since the latter two are more common and more thoroughly understood, they are often given as a diagnosis over Zika. Before blood sample analysis, the doctors had no idea what the disease could have been. “There was some thought it might be a dengue outbreak,” stated by Mark Duffy, US Air Force public health officer working for CDC’s epidemic intelligence service.

  • 2013-2014: More outbreaks occur across other Pacific islands including French Polynesia. In March of 2014, infants were diagnosed with Zika virus according to post-birth serum analysis, suggesting vertical transmission (via placenta). Blood samples are now tested for Zika virus, identifying as positive for 1505 blood donors.
  • 2015 (May): Research intensity on the Zika virus has extensively increased. Following several months of investigation, Brazil confirms presence of Zika infection. In July and October respectively, Brazil confirms a link between Zika and Guillain-Barre syndrome and microcephaly. However, no causal relation has yet been established. The Zika infection also has begun to spread to other regions in South America including Guatemala, Paraguay, Honduras and Panama.
  • 2016: More cases of fetal microcephaly are linked to the Zika virus. Countries including Haiti, France, United States, Jamaica report Zika infections. After examining medical reports of patients in French Polynesia from 2014, researchers found that an increase in reported Zika infections was associated with an increase in neurological complications and Guillain-Barre syndrome. Zika virus is confirmed to be transmitted via blood transfusion, and also via sexual intercourse.

Over time, it seems as though the Zika virus may have gotten stronger and more dangerous. Is it due to the evolution of the viral strains? Possibly. However, it is equally important to consider other factors. For example, outbreaks could be occurring more rapidly and frequently due to constant travelling and immigration in today’s world. Moreover, an increase in the number of reported Zika cases and findings may be associated with an increase in the attention given to it. This suggests that the epidemiology of the disease must incorporate biological and social factors in order to understand how to effectively control and eradicate the disease.

In any case, it is important to remain alert in avoiding the virus, especially since there is no specific cure or treatment. In the meantime, if you do have plans to travel to South America, check this to see how you can best avoid the Zika virus.

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