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As the coronavirus continues to plague countries around the world, health authorities are racing against time to identify “patient zero”. This is the index case, the first infected person, but who may not necessarily be among the first infection cluster. In fact, new evidence indicates that a number of patients outside China had contracted the virus way before China confirmed its first case.
In view of the new evidence, Micheal Ryan, WHO Health Emergencies Director pointed to a possibility that Wuhan may not be the source of the pandemic. Thus it brings the hunt for patient zero back into the spotlight.
What is “Patient Zero”?
Covid-19 has taken a total of 2.9 million lives and infected a total of 132 million as of 6 April 2021. The sudden surge of cases after relaxing restrictions has been both terrifying and worrisome to hear. It is even more compounding for someone who is far away from home.
Identifying patient zero is crucial in understanding how, when and why the outbreak began. It also sheds light on how we can prevent further infections.
While tracking down patient zero wouldn’t completely solve our problems, it could help us in mapping the path of the virus. Understanding how it spreads enables us to avoid transmission importation of the virus.
Who was the first person to contract the virus?
According to a Chinese researchers’ study in Lancet, the first diagnosis of the COVID-19 case was on December 1, 2019. Notably and significantly, this individual seems to have no contact with the Huanan Seafood Wholesale Market in Wuhan.
Analysis of sewage water samples from last November 2019 in Florianopolis, Brazil showed traces of the novel coronavirus. The finding is about two months earlier than America’s first official case of COVID-19 on January 21. And even much earlier than the first officially reported case in Brazil at the end of February 2020.
“There are many clues that can be used to track down patient zero,” said Wang Guangfa, a respiratory expert at Peking University First Hospital. What now complicates matters are the number of individuals with positive antibodies. Confounding researchers, there is a possibility that patient zero could very well be an asymptomatic patient, leaving no record to check.
Modes of animal to human transmission
A team of researchers from the USA, UK and Australia have identified two likely modes of transmission; in which the virus would jump from animals to humans based on genome sequencing.
- In the first case, the virus evolved to its disease-causing state from a non-human host (e.g. bats) into humans, via an intermediate host. This was also the cause of previous coronavirus outbreaks. In the case of SARS, humans were infected after exposure to civets. In the case of MERS, it was via camels. Researchers believe in COVID-19, there is no direct contact between humans and bats, suggesting that an intermediate host exists.
- The second theory suggests that the coronavirus passed from an animal to human before it reached a disease-causing state. It then subsequently evolved to its current infectious state through human-to-human transmission.
In the fight against mass outbreaks of viral diseases, finding patient zero is a herculean task. One that often takes a whole lot of luck and hard work. Noting that it may take decades to find patient zero, WHO director Micheal Ryan said it took years to find the first MERS patient. As for SARS, it was never fully established how the virus has been able to pass the animal-human barrier.
Thoughts to Ponder About
As a global scramble to search for “patient zero” continues, identifying patient zero is important. However, it must not fuel discrimination and racism. A panicked search for “patient zero” around Europe and the US has resulted in Asian communities being targeted for threats and even violent attacks.
by Yashwini Ravindranath
Born & raised in Malaysia, Yashwini earned her M.D. studying in Moscow's Russian National Research Medical University. With an affiliation towards research, all things coffee and the startup ecosystem, she now contributes articles to GetDocSays View all articles by Yashwini Ravindranath.
