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 II)

17 March 2014 - 3 additional cases of wild poliovirus type 1(cVDPV1) was reported with the onset of paralysis on 6, 25, and 31 Janurary 2014 from 3 new regions (North West, Adamaoua and Center) confirming continuous WPV transmission and geographic expansion of infected areas following the detection of the 4 cases in Cameroon in October 2013. Due to the continual spread of cVDPVs in Cameroon, gaps in surveillance, and influx of vulnerable refugee populations from Central African Republic, WHO had elevated the risk assessment of international spread of polio from Cameroon to VERY HIGH.

Following the confirmation of the outbreak in October 2013, Cameroon conducted 3 National Immunization Days (NIDs) followed by a fourth Nationwide Activity on the 9 March 2014. Despite independent monitoring suggesting some minor improvements in poliovirus activity, serious gaps in quality, both implementation and monitoring of cVDPVs, remained an urgent issue. Quality varies greatly by region and many houses were not visited for immunization of the children of the household. Analysis of the overall population immunity (non-polio acute flaccid paralysisdata 6-59 months) suggests an upwards of 40% of children that still remained under-immunized, with a shocking 30% of those children having not received any doses of Oral Polio Vaccine (OPV).

With the reports of new cases of poliovirus in the country, additional emergency outbreak responses were implemented, such as converting subnational immunization campaign to a full nationwide activity in April 2014. Ensuring the improvement in the campaigns that reach all children is critical in the success of the movement and measures implemented. Rapid improvements to the quality of surveillance so that the full extent of the outbreak can be determined and tracked is also crucial for the success in eradicating the threat of an international spread of polio in Cameroon. [8]

Reference:
[8] Poliovirus in Cameroon – update. (2014, March ). Retrieved June 23, 2015, from http://www.who.int/csr/don/2014_03_17_polio/en/
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