Date: Mon, 27 Apr 1998 12:00:10 +1000
Sender: POST-POLIO MED - Q&A about Post Polio Syndrome
From: Mary Westbrook
Subject: types of Polio

There are 3 types of polio virus.

• Type 1 (also known as Brunhilde)
• Type 2(Lansing)
• Type 3 (Leon)

They got their names from the cases in which they were first isolated.

Type 1 is the type most often isolated from paralytic cases.

type 3 less so and type 2 least commonly.

Type 1 was most often the cause of epidemics. Infection from one type does not necessarily confer protection against the other 2 types hence cases occurred of people having a second attack. All 3 types are included in the vaccine. Most vaccine related cases are type 2 or 3.

Paralytic polio is also classified depending on the location of the nerve cell destruction. Polio is called spinal when the paralysis involves the skeletal muscles supplied by the spinal nerves. In bulbar polio there is involvement of the muscles supplied by the cranial nerves. Bulbar polio occurred in about 5-35% of paralytic cases (depending on the epidemic) and led to problems of breathing, swallowing and speech.

It was said that you were more likely to die from bulbar polio and more likely to make a good recovery than if you had spinal polio. Of course some people had both spinal and bulbar
.. Mary
Mary Westbrook
MTWestbrook@BigPond.com

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Date: Sat, 23 May 1998 19:09:52 -0400
Sender: POST-POLIO MED - Q&A about Post Polio Syndrome
From: Eddie Bollenbach
Subject: Categories of Polio

Here is how I understand the diagnostic categories for people who acquire viral infection from polio virus, and were diagnosed as having polio:

• 1. Abortive Polio: Symptoms do not include neurologic symptoms. Mainly gastrointestinal upset and sore throat. Polio virus can be isolated from throat washings and stool. Interpretation: Polio virus growing in gut and throat lymphatic tissue and has not migrated to the spinal cord or brain. Post-Polio Syndrome would be unlikely in these cases because of the lack of neurological involvement to any appreciable extent.

• 2. Non-paralytic Polio: Symptoms include neurological symptoms: Headache, stiff neck, muscle stiffness and spasms along with other muscular symptoms. Muscle strength testing at this time and after fever breaks does not show weakness, however, there is probably undetectable permanent nerve damage to some extent. Theoretically PPS should be possible.

• 3. Paralytic Polio: All of the above symptoms but in addition residual weakness and lingering paralysis of some muscles.

  Comment: The criterion for diagnosing PPS used by NIH is partly for utilitarian purposes. For example, since it is impossible to know how many people are in the US now who have had paralytic polio, how in the world would we ever be able to venture a guess regarding the numbers of Abortive and Non-Paralytic cases? So, since we knew very little about the numbers of people who had polio and would develop PPS we had to construct rather stringent criteria. Foremost, we had to know the person had polio. And since the records for most of these were unavailable, residual paralysis was regarded as proof of paralytic polio and became a criterion for labeling a person as having PPS. So therefore the requirement of having evidence of paralysis was necessary.

It is possible that PPS does affect others who didn't know they had polio, especially those with Non-Paralytic Polio. The problem is in knowing if they had that or not. I confess to being unfamiliar with any way to show that a person has had polio by testing now. How do we know the deficit was not caused by a back injury, a small spinal cyst, Echo viruses, Coxsackie viruses, or other Enteroviruses. I am not nit picking but simply pointing out medical and scientific problems that arise when statements are made that this person or that person has PPS but has no earlier record of polio. Halsted estimates, even from the stringent criterion of having residual paralysis and then all the symptoms of PPS, only about 40% of those that have had paralytic polio have PPS. So there are a lot of problems in diagnosing PPS in Abortive or even Non-Paralytic cases of polio even though there may be some PPS.

Another problem is we don't _really_ know what causes PPS. We know that late nerve damage occurs but we don't really know why to any level of scientific confidence. There are just hypotheses (guesses) now. The two most common are:

• 1. The overuse idea
• 2. Persistent infection of some kind

Other proposals include auto-immune reactions, environmental chemicals...etcetera.

Halstead, in his Scientific American article on PPS also stated that 1 to 2% of _people infected_ have paralytic polio. The others are Abortive, and Non-Paralytic, I guess. If only 40% of the paralytic experience PPS (using Polio Task Force criteria) I don't know where we are with respect to those other types.

Finally, Sub-Clinical polio has an important and proper usage (I am not being pedantic,. just accurate so that we all stay on the same page). It means no clinical signs or symptoms of the disease. So therefore it is impossible to detect subclinical infections except for the fact that often, after they occur, the person develops an active immunity to the infection. This is why many diseases like chicken pox and polio are childhood diseases. Most of the population, unaware, had subclinical infections earlier.

Eddie