Section 4 Poliomyelitis

Introduction of Poliomyelitis

Poliomyelitis is an acute enteric infectious disease caused by poliovirus. Among people infected with poliovirus，most show subclinical infection without any symptoms，but some infected people may develop the symptoms including fever，sore throat，malaise，nausea and diarrhea that resemble common cold. Few infected people，due to poliovirus invading central nervous system，develop neuropathy in anterior horn cells of the spinal cord（particularly cervical and lumbar segment） resulting in asymmetric flaccid paralysis，which is the main presentation of paralytic poliomyelitis. In some severe cases，predominantly occurring in children，the damage may involve brainstem and cerebrum and threatening life，which is called child paralysis or baby paralysis.

China was a poliomyelitis-stricken area in the past. Several decades’ endeavor for controlling this disease has turned China into a poliomyelitisfree country. China persists in systemic and vigilant surveillance and adopts a category of cases of acute flaccid paralysis（AFP） resembling poliomyelitis into targets of surveillance and report，maintaining the AFP reporting rate in children younger than 15 years old higher than 1/100 000，which assist in discovering poliomyelitis cases caused by wild poliovirus，facilitating achievement and maintenance of poliomyelitis-free state.

Acute flaccid paralysis（AFP） includes any acute flaccid paralysis cases with unknown etiology. For instance the cases of children under 15 years old that are primarily diagnosed as Guillain-Barre Syndrome（GBS） are reported，investigated and treated as poliomyelitis suspects. AFP means a group of symptoms，not a certain disease. Diseases that can cause AFP include poliomyelitis，Guillain-Barre Syndrome，acute myelitis，injurytic neuritis，nonpoliovirus enterovirus infection，polyneuropathy，neurodocitis，mononeuritis，plexitis，periodic paralysis，myopathy，and acute polymyositis. All the above diseases can present the symptoms of AFP.

1. Diagnostic criteria

According to the virological diagnostic criteria at the late stage of eliminating poliomyelitis，the AFP cases are classified as confirmed cases，clinical diagnostic cases and excluded cases.

（1）Confirmed cases：

cases with wild poliovirus isolated.

（2）Excluded cases：

cases in which qualified feces specimen is available，from the samples wild poliovirus can not be isolated，and polio cases are excluded by experts of provincial level.

（3）Clinical diagnostic cases：

cases in which qualified feces specimen is not available，paralysis remains and death or lost follow-up occurs 60 days after the onset of illness，and polio cases are diagnosed by experts of provincial level.

2. Major measures dealing with the polio epidemic

（1） Polio cases and suspects：discovery，diagnosis，reporting，isolation，treatment，investigation，sampling，delivering and detection should be as soon as possible.

（2） Once a poliomyelitis case is confirmed，take actions such as sweeping-off immunization.

急性弛缓性麻痹流行病学个案调查表

Epidemiological Questionnaire for Cases of Acute Flaccid Paralysis

Questionnaire

急性弛缓性麻痹病例麻痹60天后随访调查表

Follow-up Questionnaire for Cases of Acute Flaccid Paralysis 60 Days after the Onset of Paralysis

（本节编者-陈纯　本节核对-曾庆　罗业飞）