Polio (Greek polios "grey" myelos "marrow" and ite "inflammation"), also known as disease-Heine Medin or simply polio, is an acute infectious disease that attacks the grey matter of the spinal cord.
It is caused by a virus, which Man is the only natural host, which is transmitted through faecal-oral or by postillons emitted during coughing or sneezing. The poliovirus (RNA virus of the family Picornaviridae, gender Enteroviruses) generally addresses the digestive system, causing symptoms similar to those of flu and it is in most cases eliminated by the immune system. But it happens in about 1 in 100 that it extends to the nerve cells and causes damage to the horns drive past the spinal cord. The virus attacks the nerve cells so that control muscles (motor) leaving intact the adjacent neurons that control sensory functions, urinary, sexual ... Up to 95% of motor may be affected, but after the acute phase of illness motor survivors are able to establish new connections and the patient may lose up to 10% of its motor without neurological final.
When the attack is massive, it causes paralysis local fatal in about 10% of cases, muscular atrophy and often irreversible. It usually affects children under five years and was one of the most terrible scourges of childhood. Polio affected more than 600 000 children per year worldwide and enfermait thousands in the lungs of steel. These aircraft were used to create a negative pressure around the chest, causing the air inside the lungs and allows for artificial respiration.
Polio has no cure, only vaccination can protect effectively. It is produced by subcutaneous injection or ingestion. For the child, it provides immunity for 5 years on condition that there was a recall after 12 months. For adults recall can be done every 10 years. The vaccine was developed by microbiologist [U.S.] Jonas Edward Salk in 1952. The mass vaccination campaigns were then put in place, which led to a decrease rapidly frequency of the disease. The "Type 2" has disappeared from the planet in 1999. The "Type 3" seems to be confined to Africa, excluding Egypt.
The monovalent oral polio vaccine, called mOPV, "Type 1", induces an immune response of 70%.
For centuries, the virus has remained endemic and relatively benign, causing only a few sporadic cases.
Around 1880, improved hygiene led to the reduction of infections immunisantes natural poliovirus in young children. The first clinical cases occur in northern Europe.
The disease affects the region of New York in 1916. In 1952, more than 50 000 people are affected the USA, France made a polio victim to 100 000 inhabitants.
The first tests of the vaccine injection Jonas Salk are made in 1954. The first mass vaccination campaign was marked by providing an important defective batch (non-attenuated live virus) leading to nearly 220 000 infections including 70 000 patients, 164 severe paralysis and 10 deaths
Albert Sabin creates an oral vaccine in 1961.
An epidemic is halted the USA in 1965. The rate of new infections fell to 1 per 10 million people.
In 1988, during its 41st General Assembly, the World Health Organization (WHO), with 166 Member States launched a global initiative to eradicate polio by the year 2005. The target was secondarily delayed to 2010.
In 1992 it discovered an outbreak of polio in the Netherlands in a group that refuses vaccination.
In late 1999 the number of cases had dropped by 95% with 7 094 new cases for 20 000 patients in total and the number of affected countries rose from 125 to 30, disappears across the American continent, Western Pacific, China and Europe.
The year 2004 has seen an increase in polio cases (1 300 against 800 in 2003). The number of reported cases in 2005 reached 1 650 and exceeds 1 760 cases in 2006.
The disease remains a major public health problem for many countries in Africa and Asia, where it still presents a concern in Afghanistan, Egypt, India (over 500 cases in 2006), Niger, Nigeria (nearly 1 000 cases in 2006) and Pakistan.
The causes of this stagnation and even regression this are complex. They are due to recurring problems of access to potable water, poor sanitation, and the delay in vaccination campaigns in two states (State of Kano and Zamfara) north of Nigeria, where Muslim leaders launch rumours accusing the Americans of wanting to contaminate by AIDS and make them sterile. The increase in polio cases in Nigeria has spread the disease in Saudi Arabia during the pilgrimage to Mecca, and then reach Indonesia, or more than 100 cases were reported in early July 2005.
The disease has also reappeared in Indonesia, 225 cases were diagnosed in 2004. A major campaign of 24 million vaccinations in one day was conducted on August 29, 2005 with a mobilization unprecedented media in the country. The last case described in this country in February 2006.
The cases are mainly confined geographical areas where the immunization coverage is sub-optimal (30% of unvaccinated children in Nigeria, cases in India are limited to one region also reluctant to vaccinations). The presence of sporadic cases in people vaccinated properly raises questions.
* Affects more men than women
* Exercise muscle fatigue and muscle
* Intramuscular injection
* Congenital immune deficiency
* Genetic factors (chromosome 19)
The post-polio syndrome
Thirty to forty years after the acute phase of the disease, while their overall condition had long been stabilized, patients feel a great fatigue, progressive muscle weakness and joint pain. Sometimes these symptoms accompanied by breathing difficulties or muscular atrophy.
The post-polio syndrome was first described by neurologists Jean-Martin Charcot and Fulgence Raymond in 1875. It affects about one survivor out of two.
There are two types of vaccine:
* A virus attenue (who is still alive) and administered orally whose first versions were developed by Albert Sabin in 1960. Since it has been improved and is effective against all three types of poliovirus serological and is inexpensive. Its characteristics have made this type which is used by WHO in its eradication campaign. However, the disadvantage, as any kind of vaccine virus attenue have in very rare cases of serious side effects.
* An inactivated virus (which is killed) and administered by injection. It was developed by Jonas Salk in 1952 and is like all other vaccines of this type more expensive than the previous and less effective, but has no risk at the individual level. It is less effective because it does not block intestinal infections (oral) and prevents only paralysis (which are also the most severe symptoms which lead to sequels).