11/11/2013

The most recent Type Polio 3 viruses seen were spotted in Nigeria in November 2012. Pakistan

One of 2 remaining types of Polio viruses may be wiped out; not seen in a year

TORONTO - The effort to rid the world of polio is too often a journey of one step forward and two steps back, with the heartbreaking news that polio is crippling toddlers in war-ravaged Syria the most recent evidence of that stuttering progress.
Still, there is some good news on the polio front.
Sunday marks one year since Type 3 polio viruses have been found, suggesting vaccination efforts may — heavy stress on may — have wiped out the second of three strains of polio.
If the Type 3 viruses are indeed gone, it will mean that only Type 1 polio viruses remain to be vanquished before the long-overdue goal of polio eradication can be realized.
Reaching the one-year milestone has made people involved in the frustrating and expensive polio eradication program hopeful that transmission of  Type 3 viruses may have stopped. But they warn it would be unwise to declare victory just yet.

"I think the available information is cause for some cautious optimism. But in particular in Nigeria I think we would look for more evidence before we would ... uncork the champagne," says Olen Kew, a senior virologist specializing in polio at the U.S. Centers for Disease Control in Atlanta.
The most recent Type 3 viruses seen were spotted in Nigeria in November 2012. Pakistan, another of polio's strongholds, last reported a Type 3 infection in April of 2012. And the CDC's polio laboratory, which monitors movement of viruses worldwide, had been reporting that the number of lineages of Type 3 viruses — families within the overall group — has been markedly declining in the past couple of years.
But in both Nigeria and Pakistan, the most recent Type 3 cases were found in politically troubled parts of the countries where vaccination teams struggle for access to children. In Nigeria, the experts know, surveillance for the virus is not as strong as it might be — hence Kew's comment urging caution.
In Pakistan, however, environmental surveillance — testing sewage for polio viruses — makes the situation look more promising.

The last Type 3 virus there was seen in the FATA, the federally-administered tribal areas bordering Afghanistan where polio vaccinators have often been refused entry for long periods. The nearest site where environmental testing is done is Peshawar, where last month a bomb was detonated while polio vaccinators collected their kits.
"The viruses from the tribal areas find their way into Peshawar (sewage) regularly," says Kew. "And the fact that we've not seeing it in the environment in Peshawar is really quite encouraging."
The CDC is one of founding partners in the polio eradication project, which started in 1988. The World Health Organization, UNICEF and the service club Rotary International are the other founding partners; in more recent years the Bill and Melinda Gates Foundation has become a key player in the effort.
Buoyed by the success of the smallpox eradication program — the disfiguring disease was declared eradicated in 1979 — and by the ease with which the Americas stopped polio transmission, the world embarked on the plan to get rid of polio by the year 2000.
But this task is vastly more complicated, because of the nature of polio.
Whereas people who were infected with smallpox were easy to spot — they developed the scarring rash — much of polio's spread is invisible to the eye. Only a small portion of cases develop paralytic polio. And where there was one type of smallpox, there were actually three strains or serotypes of polio.
"In a sense, polio eradication should be called polios eradication," says Dr. Walter Orenstein, who works on the eradication effort through the Emory Vaccine Center at Emory University in Atlanta.
"As opposed to smallpox, where we had to get rid of one agent, with polio we're really having to get rid of three agents."
One of those serotypes is actually long gone. Type 2 polio viruses haven't been spotted since 1999. And now it appears Type 3 viruses may be following Type 2 into the history books.
Each of the three viruses has unique qualities. Type 1 is the most aggressive and is able to spread long distances with ease. The viruses responsible for the Syrian outbreak as well as those being discovered in Israel sewage this year are all Type 1s from Pakistan.
Type 3 is a poor traveller. It has rarely been seen to jump long distances. But another quirk of the virus is making the experts watching this situation wary about claiming victory.
Of all the viruses, Type 3s are least likely to paralyze the children they infect. It is estimated that only one in 1,200 Type 3 infections leads to paralysis. By comparison, Type 1 viruses paralyze about one out of every 150 or 200 infected children.

There are only two ways to detect spread of polio viruses — by finding them in sewage, where environmental surveillance is done, and by finding paralyzed children. Type 3's low paralysis-to-infection rate makes it harder to spot.
"Because of the lower case-infection ratio, and because of the state of surveillance, (Type 3 can go) under the radar," says Dr. Steven Wassilak, a medical epidemiologist in CDC's global immunization division.
"And so when we hit the anniversary, particularly in an area" — Nigeria — "where the surveillance is less rigid than even in Pakistan, we have to be extremely cautious about what it means."
Still, the suggestion that Type 3 viruses may be gone is a welcome positive sign, coming in what has been a year of both record low cases and some extremely tough setbacks for the polio program.
"The prospects for completing eradication, they go up substantially with each serotype you knock out," says Dr. Bruce Aylward, the Canadian who has fronted the WHO's polio efforts for years.
"Mainly because of what you learn getting there.... And then of course there's that very real impact it has with governments," says Aylward, the WHO's assistant director-general for polio, emergencies and country collaboration.
The reference to governments is an allusion to the polio eradication program's constant struggle to raise funds. The effort has cost more than US$10 billion so far and it is estimated it will take another US$5.5 billion to complete the job.
Major funders have included Rotary International, the Gates Foundation and a number of governments, including Canada. Earlier this year the federal government pledged to contribute $250 million for polio eradication over the next six years.
Post Polio Litaff, Association A.C _APPLAC Mexico

The Polio Crusade

THE POLIO CRUSADE IN AMERICAN EXPERIENCE A GOOD VIDEO THE STORY OF THE POLIO CRUSADE pays tribute to a time when Americans banded together to conquer a terrible disease. The medical breakthrough saved countless lives and had a pervasive impact on American philanthropy that ... Continue reading..http://www.pbs.org/wgbh/americanexperience/polio/

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