Answer the following commets | Biology homework help

1. Why has Poliovirus not been eradicated to date?

Several reasons have historically led to that poliovirus not being eradicated. Some of them are listed as follows:
1) People’s misconception about Poliovirus.
2) Insecurity within the country, especially, in the countries in which wild polioviruses have been transmitting endemic. 
3) Poor health system. Also, the poliovirus vaccine is more complicated to administer compared to some other vaccines such as the smallpox vaccine. For instance, the oral poliovirus vaccine needs to be kept refrigerated and administrated multiple times.
4) Mistrust of the West and their vaccination programs in afflicted areas. For instance, 8 poliovirus vaccinators were killed in northern Afghanistan in February 2022 which forced the United Nations to stop the vaccination in two provinces. The following month, another vaccination worker was killed in northwestern Pakistan. Since 2012, more than 70 vaccinators have been targeted in Pakistan as well.
5) Underscoring the poliovirus dangers. This resulted in reemerging of the virus in southern Africa in 2021. Also, several vaccine-derived cases appeared in the United States and Israel in 2022. Furthermore, the war in Ukraine disrupted the government’s efforts to prevent the virus outbreak in the west side of the country. 
6) Undermining poliovirus vaccination campaigns by misinformation. For instance, a mob in Khyber Pakhtunkhwa province of Pakistan burned a healthcare facility in 2019 after a rumor that vaccinated children had fallen ill due to the expiration of their vaccine doses. 
7) a Million children missed routine vaccinations due to the COVID-19 pandemic. The spread of the new coronavirus in early 2020 deteriorated the situation as poliovirus vaccination was halted around the world. The countries such as Afghanistan and Pakistan observed spikes in poliovirus-afflicted children in 2020.

Where do pockets of Poliovirus infections caused by wild-type polioviruses occur?

Pakistan and Afghanistan are the countries in which wild-type polioviruses are transmitted endemic. Among the 110 cases of wild poliovirus throughout the world in 2020, two-thirds were in Pakistan and the remaining one-third were in Afghanistan. In 2014, Pakistan reported 300 cases of paralytic poliovirus; however, it decreased to only one case in 2021. Moreover, health experts are warning about the reemergent of poliovirus in Ukraine amid Russia’s invasion in early 2022. Upon the appearance of several poliovirus vaccine-derived cases in late 2021, the WHO and the health ministry of Ukraine set up a vaccination campaign, but it has been disrupted by war. The resurgence of poliovirus often occurs in unstable areas where health systems are disrupted by war as well as in areas where refugees have resettled. For instance, Syria observed a reemergence of the disease between 2013 to 2014 during the civil war.

2. Where do pockets of Poliovirus infections caused by wildtype polioviruses occur?

There are still isolated pockets of wildtype poliovirus infections in a few nations, mostly in portions of Asia and Africa. Afghanistan, Pakistan, and Nigeria are the three nations where the wildtype poliovirus is still endemic, according to the World Health Organization (WHO), which means that the virus is still actively spreading and resulting in new cases.

There have occasionally been wild type poliovirus outbreaks outside of these nations, frequently as a result of the importation of the virus from endemic nations. For instance, a poliovirus outbreak in the Philippines in 2019 was associated with a strain of the virus that had its origins in Pakistan.

Rare instances of poliovirus infections have also occurred in regions that have been deemed polio-free, frequently as a result of inadequate immunization rates or other flaws in immunization protocols. For instance, Papua New Guinea, which had been polio-free for 18 years, reported a case of the wildtype poliovirus in 2018. In response, the government started a widespread vaccination program to stop the virus from spreading.

The global incidence of wildtype poliovirus has been significantly reduced, and efforts to eradicate it are still underway. Even so, there is a chance of importation and outbreaks in other locations as long as the virus is still present in a few nations. To stop the poliovirus from reemerging, it is crucial to maintain high vaccination rates and surveillance.

3. Why has Poliovirus has not been eradicated to date?                                                                                                           

  • In countries like Pakistan and Afghanistan militant groups such as The Tehreek-e-Taliban, Al Qaeda, and the northern Nigerian Boko Haram movement pose a significant obstacle to the elimination of polio in their nations.
  • The failure of polio eradication campaigns in these areas is due to misunderstandings about the polio vaccine among the populace, internal unrest, and a subpar healthcare system. Children in all nations are at risk of catching polio as long as there is even one afflicted child. Inability to eliminate polio from these final bastions could lead to a global resurrection of the virus.
  • In London and New York City, where it had previously been eradicated, polio has been rediscovered. Health professionals are worried about declining immunization rates. Brazil, the Dominican Republic, Haiti, and Peru are at a serious risk for the reemergence of polio, according to the Pan American Health Organization (PAHO), as declining vaccination rates during the COVID-19 pandemic have resulted in historically low levels of protection against the illness. According to PAHO, regional vaccination rates against polio have dropped to roughly 79%, the lowest level since 1994. When it comes to avoiding paralytic poliomyelitis, both vaccines are very successful. Polio also exists today because people have biased opinions on the vaccines in the market. In the UK for example, the oral vaccine is particularly effective at minimizing fecal shedding of the virus and, as a result, is better at reducing transmission. But extremely rarely, the oral immunization might result in paralysis (about two to three cases per million doses). Because of this, the majority of nations, now favor using the inactivated vaccine. Nonetheless, only a few nations continue make use of the oral vaccine. We might find “vaccine-like” polioviruses in wastewater because young children who receive the live vaccine will briefly shed it in their feces. This typically occurs in the UK two or three times a year, where a weaker variant of the virus is found in the sewerage as the result of oral immunization abroad. This isn’t necessarily harmful, but if these viruses are allowed to spread across a population over time, it’s feasible that they could change and return to a form that paralyzes people. They are then categorized as polioviruses derived from vaccines. Less children who have received all of their recommended vaccines increases the likelihood that vaccine-like and vaccine-derived polioviruses may circulate.
  • Migrating populations also pose a significant barrier for the eradication of polio as well                                             .


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