EMERGING VIRUSES

(Prepared by: Isha Gaikwad, 20220901015)

Newly emerging viruses such as the Ebola virus, severe acute respiratory syndrome (SARS)-, Middle East respiratory syndrome (MERS)-coronavirus, and the avian influenza virus are serious threats to public health. The swine flu pandemic in 2009 reminded us of the Spanish flu that killed over 40 million people. Newly emerging viruses could be either a novel previously undescribed virus or a variant of a previously known virus. Variants of previously described viruses are also called "remerging viruses" and can cause new epidemics with considerable virulence. The influenza virus that caused the 2009 pandemic was a variant of an existing virus.

Public health authorities are increasingly relying on quarantine at airports and seaports to monitor the emergence of new viruses and their transmission due to the expansion of international trade and travel.

EBOLA VIRUS

Ebola outbreaks have been documented since the first one in 1976. Ebola fever has a fatality rate that is around 90%.  Ebola outbreaks have mostly only occurred in Africa. Due to the high case fatality rate and quick patient death, there is little chance that Ebola will spread and cause a broad epidemic.

                                                                  Source: https://eyewiki.aao.org/Ebola_Virus

WEST NILE VIRUS

An effective illustration of the spread of a zoonotic virus spread by mosquitoes as a result of climate change is the WNV5 pandemic in North America. WNV is a flaviviridae family member that is spread through mosquitoes. It also goes by the name arbovirus. It was first discovered in the East African country of Uganda's West Nile subregion in 1937.

                                                                  Source: https://eyewiki.aao.org/

SIN NOMBRE VIRUS 

In 1993, the "Four Corners" region of the western United States received its first reports of a mysterious respiratory ailment that was killing young Navajo. Investigators began searching for the culprit in rodents when they saw a clinical resemblance to the hantavirus infection that occurred during the Korean conflict (1950–1953). Up to that point, no known hantavirus infections had ever been documented in the US.

                                       Source: https://www.utmb.edu/virusimages/VI/sin-nombre-virus-%28hantavirus%29 

NIPAH VIRUS

As it caused an outbreak of neurological and respiratory diseases on a pig farm in peninsular Malaysia in April 1999, the Nipah virus was first discovered there. 1 million pigs were killed, and there were 257 human cases and 105 fatalities as a result of the pandemic. The majority of the human and pig respiratory and encephalitic signs of infection from the Malaysian outbreak.

                                      Source: https://en.wikipedia.org/wiki/Nipah_virus

SARS-CORONAVIRUS (SARS)

The SARS-CoV is the virus that causes ARS, a respiratory virus with zoonotic origins. A SARS outbreak in southern China between November 2002 and July 2003 resulted in 8273 cases and 775 fatalities across several nations. According to the WHO, Hong Kong had the most cases (9.6% death rate).

                           Source: https://www.news-medical.net/health/The-Naming-System-Behind-SARS-CoV-2.aspx

Why Do New Viruses Emerge?

Why do fresh human pathogenic viruses keep appearing? Most often, outbreaks have been observed to take place in tropical areas devoid of any habitation. The fundamental reason for the creation of novel viruses is thought to be an increase in human contact with wild animals as a result of the extension of the human habitat. Wild animal contact with humans has increased as a result of environmental changes like rainforest development. As a result, viruses that were previously exclusive to rainforests can now infect a new human host.

References

10.1016/B978-0-12-800838-6.00021-7

https://doi.org/10.1142/8268