What is Polio?

Polio (also known as Poliomyelitis)

An infectious disease that can be transmitted from person to person. Polio is caused by poliovirus, an enterovirus. Poliovirus is most well known for causing paralysis in young children.[0]

Poliovirus is part of the picornavirus viral family, a taxonomic grouping that includes other familiar viruses such as the rhino virus and hepatitis A virus. These viruses are most known for their icosahedral capsid(20 faces) structure that lacks a viral envelope and carries the positive-sense single stranded RNA genome. Further characteristics include being able to withstand low pH and thus able to pass through the stomach to infect and replicate in the intestinal epithelial cells and being incredibly infectious through the fecal-oral route. [0]

*funfact: Humans are the only natural hosts of this disease. Chimapanzees, Green African Monkeys etc can only be experimentally infected.

Whilst most infections are asymptomatic, viral particles that gain entrance into the central nervous system can replicate in neurons and destroy cells that govern muscle function resulting in flaccid paralysis.[0] To simply put it, the poliovirus invades the brain and spinal cord and may cause paralysis. However, 72 out of 100 infected people will not have any visible symptoms.[1]

Symptoms commonly include:
-Sore throat
-Fever
-Feeling lethargic
-Nausea
-Headache
-Stomach pains

More severe symptoms include:
-Paresthesia ( pins and needles in arms and legs or both)
-Meningitis (Inflammation of the brain & spinal cord)
-Paralysis or weakness of arms and legs

*Paralysis may be fatal due to the inactivation of muscles that aid in respiration. Hence Polio is often referred as a paralytic infection.

Poliovirus is easily transmitted through contact with an infected person. The virus lives in the infected person's throat and intestine. It enters the body though contact of feces and though less common, sneezes and coughs. Contamination of everyday items after not properly washing after using the toilet may speed up the infection rate. This is especially so in rural countries living in unsanitary conditions.

*The poliovirus may be cured with Oral Poliovirus Vaccine(OPV) or Inactivated Poliovirus Vaccine(IPV) but there are cases of Post-polio syndrome where patients recover after a vaccination but there happened to be a relapse of the patient's previous condition. [1]

Reference:
[0]Poliomyelitis. (n.d.). Retrieved July 31, 2015, from https://microbewiki.kenyon.edu/index.php/Poliomyelitis
[1] What Is Polio? (2014, October 15). Retrieved July 31, 2015, from http://www.cdc.gov/polio/about/

WHO Wild Poliovirus update (Week ending 24 June)

According to the Headlines, an outbreak response assessment took place in the Horn of Africa in June. The research team came to the conclusion that the transmission of the virus in Kenya and Ethiopia has been interrupted despite the possibility of an undetected transmission in Somalia.

Furthermore, 5 cases of circulating cVDPV1 was reported in Madagscar with dates of onset paralysis in April and May 2015. These cases are genetically linked to that of September 2014 cases indicating a prolonged and widespread circulation of cVDPV1. The emergency outbreak response has now been increased and intensified to build an immunity against the virus in the country. approximately 25% of the children across Madagscar is underimmunized.

WHO is now closely monitoring the countries that has been detected positive for poliovirus since the year 2014, namely Pakistan, Afghanistan, Somalia, Nigeria, Cameroon, Equatorial Guinea, Iraq, Syrian Arab Republic and Ethiopia. By 24 June 2015, 25 cases of wild poliovirus have been officially reported in Pakistan with the onset of paralysis last documented on 24 May 2015. 4 cases of wild poliovirus have also been reported in Afghanistan, with  the last onset of paralysis documented there on the 5 May 2015. Finally, 0 cases for the remaining countries in the year 2015 with last documented cases of poliovirus induced paralysis in the year 2014.

Despite the 29 documented cases so far, WHO has recognized a significant amount of improvement in the number of reported cases compared to the year 2014, where by this period, there were 83 cases, 6 cases, 1 case, 4 cases, 3 cases, 4 cases, 2 cases and 1 case each of wild poliovirus documented in Pakistan, Afghanistan, Somalia, Nigeria, Cameroon, Equatorial Guinea, Iraq, Syrian Arab Republic and Ethiopia respectively. The mass improvement is shown when data of cases reported in the same period was collected of the total global cases in 2015 compared to 2014 was decreased from 105 to 29. [13]

Reference:
[13] World Health Organization Wild Polio Virus Update Week ending 24 June. (2015, June 24). Retrieved July 26, 2015, from http://clubrunner.blob.core.windows.net/00000050024/en-ca/files/sitepage/polio-headlines/24-jun-2015/Polio-Headlined-JUne-24.pdf
Posted by

No comments:

Post a Comment

Subscribe to: Post Comments (Atom)