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/

Cameroon Case (Part III)

17 April 2014 -  In Equatorial Guinea, 3 new wild poliovirus type 1 (WPV1) cases was reported. There has not been any polio cases in Equatorial Guinea since 1999 and through Genetic Sequencing, it was indicated that the poliovirus strains belonged to that of the poliovirus strains isolated in the Cameroon poiliovirus outbreak. The cases of onset paralysis in Equatorial Guinea was between 28 January and 24 March 2014 from Centro Sur, Bioko Norte and Litoral. Outbreaks in Equatorial Guinea led to an emergency outbreak response with drafted activities to be carried out, such as National Immunization Days with Oral POlio Vaccine on 21-24 April 2014. An estimated 40% children were immunized fully against polio in the country.

Due to the possible spread of poliovirus across the regions, immunity levels and surveillance sensitivity were constantly assessed in neighboring countries, particularly in Gabo and the Republic of Congo. In preparation of a possible spread of poliovirus in Gabon and Republic of Congo, both countries scheduled Nationwide Immunization campaigns in April and May 2014. [5]

WHO stressed the importance of being fully immunized before entering countries infected or close to countries infected with poliovirus. WHO also stressed the importance of increasing surveillance for acute flaccid paralysis for quick detection and to facilitate emergency outbreak responses. WHO finally stressed to neighboring countries, territories and areas close to infected areas to maintain uniformly high routine immunization coverage at the district level to minimize consequences of any new virus introduction. [9]

Reference:
[9] Update on polio in central Africa - polio confirmed in Equatorial Guinea, linked to outbreak in Cameroon. (2014, April ). Retrieved June 26, 2015, from http://www.who.int/csr/don/2014_4_17polio/en/
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