7/10/2014

Old-fashioned vaccine fights Polio resurgence


A child receives a vaccine in a makeshift field clinic of the Doctors Without Borders (MSF) organisation in Bangui on January 7, 2014
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Paris (AFP) - A jab to protect children against polio that fell out of favor in the 1960s should be given a frontline role to help stamp out the disease, doctors reported in The Lancet on Friday.
The injection can provide better and long-lasting protection against the polio virus when used to supplement oral vaccine, which replaced it in most countries, they said.
Oral polio vaccine (OPV) protects individuals against contracting the disease, but they can still be infected by the virus.
It replicates in the gut and can then be passed to others through faecal-contaminated water, thus imperilling unvaccinated children.
Scientists at Imperial College London and the Christian Medical College in Vellore, in southern India's Tamil Nadu state, investigated whether the old-fashioned vaccine still had a part to play.
Their study involved 450 children from a poor urban area of Vellore, all of whom had received the oral vaccine as part of a standard innoculation programme.
Half of the children were then given a dose of the injected vaccine, which contains an inactivated virus, and the other half given nothing.
A month later, the children were given a dose of live oral vaccine, whose formula includes a tiny amount of live polio virus, the goal being to safely simulate re-infection.
A week later, their stools were tested to see if the polio virus was present -- specifically the two strains of the virus, serotypes 1 and 3, which are resisting eradication.
Among children who had received the injected vaccine, there were 38 percent fewer who had traces of serotype 1, and 70 percent fewer with serotype 3, compared to those who did not get the jab.
"Because IPV (injected polio vaccine) is injected into the arm, rather than taken orally, it's been assumed it doesn't provide much protection in the gut and so would be less effective at preventing faecal transmission than OPV," said Jacob John of the Christian Medical College.
"However, we found that where the children already had a level of immunity due to OPV, the injected vaccine actually boosted their gut immunity," he said in a press release.
He added: "In the 1960s there was extensive rivalry between the scientists who developed the two vaccines, with OPV eventually becoming the most popular.
"But it looks as if the strongest immunity can be achieved through a combination of the two."
- Tried and trusted -
Also called the inactivated polio vaccine or the "Salk vaccine," after its inventor, Jonas Salk, who developed it in 1955, the jab has long been considered an astonishingly safe and effective weapon against polio.
It is still used in dozens of countries, but in more than 120 others, oral vaccine is the exclusive choice, as it is cheaper, easier and quicker to administer.
The new findings add support to guidelines issued in February by the UN's World Health Organization (WHO).
The agency recommended that all children receive at least one dose of injected vaccine in countries that solely use OPV, in order to broaden the attack on all serotypes of the virus.
Polio, a crippling and potentially fatal disease that mainly affects children under the age of five, has taken a beating from a quarter-century vaccination effort.
In 1988, the disease was endemic in 125 countries, and 350,000 cases were recorded worldwide, according to the WHO.
Today, the virus is considered endemic in only three countries -- Afghanistan, Nigeria and Pakistan, where the vaccination campaign has been attacked by Islamists and tribal leaders.
The refugee crisis in Syria is considered another potential source of infection, as the vaccination programme there has been disrupted by war.
Health watchdogs are worried for unvaccinated children in those countries and in neighbouring countries where the vaccination guard may have slipped.
In May, the WHO declared that polio had returned as a "public health emergency" after three cases of cross-border transmission of polio were detected between January and April -- from Pakistan to Afghanistan, Syria to Iraq and Cameroon to Equatorial Guinea.
Post Polio Litaff, Association A.C _APPLAC Mexico

The Polio Crusade

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Erradicación de La poliomielitis

Polio Tricisilla Adaptada

March Of Dimes Polio History

Dr. Bruno

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A 41-year-old man developed an acute illness at the age of 9 months during which, following a viral illness with headache, he developed severe weakness and wasting of the limbs of the left side. After several months he began to recover, such that he was able to walk at the age of 2 years and later was able to run, although he was never very good at sports. He had stable function until the age of 18 when he began to notice greater than usual difficulty lifting heavy objects. By the age of 25 he was noticing progressive difficulty walking due to weakness of both legs, and he noticed that the right calf had become larger. The symptoms became more noticeable over the course of the next 10 years and ultimately both upper as well as both lower limbs had become noticeably weaker.

On examination there was wasting of the muscles of upper and lower limbs on the left, and massively hypertrophied gastrocnemius, soleus and tensor fascia late on the right. The calf circumference on the right exceeded that on the left by 10 cm (figure1). The right shoulder girdle, triceps, thenar eminence and small muscles of the hand were wasted and there was winging of both scapulae. The right quadriceps was also wasted. The wasted muscles were also weak but the hypertrophied right ankle plantar flexors had normal power. The tendon reflexes were absent in the lower limbs and present in the upper limbs, although the right triceps was reduced. The remainder of the examination was normal.

Figure 1

The patient's legs, showing massive enlargement of the right calf and wasting on the left

Questions

1
What is that nature of the acute illness in infancy?
2
What is the nature of the subsequent deterioration?
3
What investigations should be performed?
4
What is the differential diagnosis of the cause of the progressive calf hypertrophy?

Answers

QUESTION 1

An acute paralytic illness which follows symptoms of a viral infection with or without signs of meningitis is typical of poliomyelitis. Usually caused by one of the three polio viruses, it may also occur following vaccination and following infections with other enteroviruses.1 Other disorders which would cause a similar syndrome but with upper motor neurone signs would include acute vascular lesions, meningoencephalitis and acute disseminated encephalomyelitis.

QUESTION 2

A progressive functional deterioration many years after paralytic poliomyelitis is well known, although its pathogenesis is not fully understood.2 It is a diagnosis of exclusion; a careful search for alternative causes, for example, orthopaedic deformities such as osteoarthritis or worsening scoliosis, superimposed neurological disorders such as entrapment neuropathies or coincidental muscle disease or neuropathy, and general medical causes such as respiratory complications and endocrinopathies.3

QUESTION 3

Investigations revealed normal blood count and erythrocyte sedimentation rate and normal biochemistry apart from a raised creatine kinase at 330 IU/l (normal range 60–120 IU/l), which is commonly seen in cases of ongoing denervation. Electromyography showed evidence of denervation in the right APB and FDI with polyphasic motor units and complex repetitive discharges, no spontaneous activity in the left calf and large polyphasic units in the right calf consistent with chronic partial denervation. Motor and sensory conduction velocities were normal. A lumbar myelogram was normal. Magnetic resonance imaging (MRI) scan of the calves is shown in figure2.

Figure 2

Axial T1 weighted MRI scan (TR 588 ms, TE 15 ms) of the calves, showing gross muscle atrophy and replacement by adipose tissue on the left, and hypertrophy of the muscles on the right, with only minor adipose tissue deposition

QUESTION 4

The differential diagnosis of the progressive calf hypertrophy is given in the box.

Causes of calf muscle hypertrophy

Chronic partial denervation

  • radiculopathy

  • peripheral neuropathy

  • hereditary motor and sensory neuropathy

  • spinal muscular atrophy

  • following paralytic poliomyelitis

    Neuromyotonia and myokymia

  • Isaac's syndrome

  • generalised myokymia

  • neurotonia

  • continuous muscle fibre activity due to: chronic inflammatory demyelinating polyradiculopathy, Guillain Barre syndrome, myasthenia gravis, thymoma, thyrotoxicosis, thyroiditis

    Muscular dystrophies

    Myositis

    Infiltration

  • tumours

  • amyloidosis

  • cysticercosis

    Link here