London, May 8 : As the Covid-19 cases surge globally, especially in India, leaving many of us wonder why it is so hard to treat, a review published in the prestigious journal The Lancet has revealed that the increase in caseloads is owing to a unique infectious profile. According to the review, there is growing evidence that the virus infects both the upper and lower respiratory tracts. The review suggests that it is unlike "low pathogenic" human coronavirus sub-species, which typically settle in the upper respiratory tract and cause cold-like symptoms or "high pathogenic" viruses such as those that cause SARS and ARDS, which typically settle in the lower respiratory tract. Additionally, more frequent multi-organ impacts, blood clots and an unusual immune-inflammatory response not commonly associated with other, similar viruses, mean that Covid-19 has evolved a uniquely challenging set of characteristics. "The emergence of severe acute respiratory syndrome coronavirus two (SARS-CoV-2), which causes Covid-19, has resulted in a health crisis not witnessed since the 1918 Spanish flu pandemic. Tragically, millions around the world have died already," said co-author Ignacio Martin-Loeches, Clinical Professor in Trinity College Dublin. While animal and experimental models imply an overly aggressive immune-inflammation response is a key driver, it seems things work differently in humans -- although inflammation is a factor it is a unique dysregulation of the immune response that causes our bodies to mismanage the way they fight the virus. "Despite international focus on the virus, we are only just beginning to understand its intricacies," Martin-Loeches said. "Based on growing evidence we propose that Cvid-19 should be perceived as a new entity with a previously unknown infectious profile. It has its own characteristics and distinct pathophysiology and we need to be aware of this when treating people," Martin-Loeches added. However, the co-author also said that it doesn't mean we should abandon existing best-practice treatments that are based on our knowledge of other human coronaviruses. But an unbiased, gradual assembly of the key Covid-19 puzzle pieces for different patient cohorts -- based on sex, age, ethnicity, pre-existing comorbidities -- is what is needed to modify the existing treatment guidelines, subsequently providing the most adequate care to Covid-19 patients. /IANS