Poliomyelitis (polio) is a highly infectious viral disease, affecting only humans of any age, but mainly children under the age of 3 (> 50% cases). There are three types (type 1, type 2, and type 3) of wild poliovirus which can invade the nervous system and can cause total paralysis in several hours. In areas with either poor hygiene or sanitation, infants are infected early in life, acquiring active immunity while still protected by maternal antibodies. Other infants who miss early contact with the virus become susceptible to infection as maternal antibodies fall.
"Iron Lung" used by polio patients unable to breath (Image: CDC USA)
Page Links: Introduction | Polio Reports | Polio Infection | History | Polio Vaccine | WWW Links |
June 2006 - Report of polio outbreak in Namibia national health authorities are preparing a response to an outbreak of wild poliovirus in Namibia, polio-free since 1996.
May 2005 - Report of polio outbreak in Indonesia Indonesia has not had a wild poliovirus case since 1995, which suggests recent introduction of a wild poliovirus form an overseas source. Global polio cases 1267 for 2004 (as of week 26 April 2005): Nigeria (792) India (136) Pakistan (53) Niger (25) Afghanistan (4) Egypt (1) (Polio Eradication Org 04 May 2005) (More? Polio Eradication Initiative)
This enterovirus enters the body through the mouth and multiplies in the intestine. Initial symptoms are fever, fatigue, headache, vomiting, stiffness in the neck and pain in the limbs.
Irreversible paralysis (mainly legs) occurs in 1 in 200 infections. Amongst those paralysed, 5%-10% die when their breathing muscles become immobilized. Although polio paralysis is the most visible sign of polio infection, fewer than 1% of polio infections ever result in paralysis. Poliovirus can spread widely before cases of paralysis are seen. As most people infected with poliovirus have no signs of illness, they are never aware they have been infected. After initial infection with poliovirus, the virus is shed intermittently in faeces (excrement) for several weeks. During that time, polio can spread rapidly through the community.
(text modified from - Polio Eradication Organization)
1961 Dr. Albert Sabin develops a "live" oral vaccine against polio.
1955 Dr. Jonas Salk develops the first vaccine against polio, an inactivated and injectable polio vaccine.
1931 Sir Macfarlane Burnet and Dame Jean MacNamara identify several types of poliovirus, known as Types 1, 2, and 3.
1916 An epidemic of polio in New York heightens concern on both sides of the Atlantic Ocean and accelerates research into how the disease is spread.
(More? see Polio Eradication Organization - History)
Ttwo types of polio vaccine:
Inactivated polio vaccine (IPV), given as an injection (polio virus used in vaccine is killed).
Live oral polio vaccine (OPV), a liquid that is swallowed (virus used in vaccine is attenuated or weakened).
Links: Normal Development- Immunization | National Immunization Program (USA) Oral Polio Vaccine and HIV/AIDS information. | Monovalent oral polio vaccine type 1 (mOPV1) Factsheet
Polio Eradication Organization "The goal of the Global Polio Eradication Initiative is to ensure that no child will ever again know the crippling effects of polio. The Global Polio Eradication Initiative is the largest public health initiative the world has ever known."
Poliovirus | Image- Pathogenesis of enterovirus infections | table - Clinical Aspects of Poliomyelitis
The Australian NHMRC (1988) recommends neonates be assessed for follow-up care under the following conditions.
(see the NHMRC WWW Page)
Alcohol "Fetal Alcohol Syndrome" | Smoking | Chemical | Drug Use | Legal Drugs | Nutrition | Viral Infection | Polio Infection | Rubella | Sexually Transmitted Diseases | Syphilis | cytomegalovirus | Iodine Deficiency
Trauma
These links require online access to Merck Manuals on Women's Health Issues. http://www.merck.com/mrkshared/mmanual_home2/sec22/sec22.jsp
Risk Factors Present Before Pregnancy
Risk Factors That Develop During Pregnancy
Diseases that complicate Pregnancy
Sudden Infant Death Syndrome (SIDS)
Malnutrition
Infection
Trauma
see also Normal Childhood Development
You should look at normal development of teh effected systems in the embryo. Development Notes
Alternatively, go on to look at Systematic Development of organs and tissues.
For those wanting to see dynamic processes of development (and have a reasonably quick connection) then the Movies pages are good for watching changes occur.
The study of human development has relied extensively on studying the process in other model animals. For those wanting to see the process of development in other species then the other embryos pages are a good start.
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Polio virus
Viruses cannot reproduce by themselves and therefore infect cells to use the cell machinery to produce more virus. Different viruses have genetic material as single- or double-stranded RNA or DNA.
The infectious virus particle is called a "virion" and is the genetic material packed in a protein shell. Viruses come in many genetic sizes, as little as 4 proteins up to 200 proteins.
Many different types of viral infections can have impacts on development, either directly by the infection or indirectly by fever and other side-effects of infection.
Please email Dr Mark Hill if you wish to make a comment about this current project.