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Context |
Adopting the WHO recommended syndromic approach to detect acute poliomyelitis cases, Acute Flaccid Paralysis (AFP) surveillance with case-based investigation started in Lebanon since 1998. Syndromic report is the notification of a health event under surveillance for which the case definition is based on a syndrome not on a specified disease. Case-based surveillance of a disease includes collecting specific data on each case.
The syndromic reporting strategy, of investigating all AFP cases allows:
- To increase the sensitivity of the surveillance system and detect the entire spectrum of paralytic poliomyelitis.
- To provide objective data with which to monitor the quality of surveillance in an individual country.
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Objective |
The objective of AFP surveillance is to evaluate the progress of the poliomyelitis eradication program. Such system can provide:
- the occurrence of poliomyelitis cases and AFP cases
- the clinical and laboratory findings of the AFP cases
- and the country capacity to detect any AFP cases, to investigate it rapidly and to achieve rapid response in case of wild poliomyelitis case.
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Legislation |
The law on infectious diseases issued on 31 December 1957, has already pointed the poliomyelitis as an immediate mandatory notifiable communicable disease by health professionals. Furthermore, the arrete 270/1 dated on 20/03/1996 has added the acute flaccid paralysis in the list of the immediate reportable diseases. Notification is done using the standard form for reporting communicable diseases.
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Case-definition |
Poliomyelitis is suspected:
- Any child under 15 years of age with AFP (whatever was the medical diagnosis)
- or any person of any age diagnosed as poliomyelitis case.
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Poliomyelitis is confirmed:
- AFP form whom wild poliovirus is isolated (processed by WHO accredited laboratory).
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The syndrome of AFP cases can result from various etiologies as Guillain Barre syndrome, transverse myelitis, traumatic neuritis, Coxackie virus, Echovirus, other Enterovirus ...
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Case notification |
AFP and poliomyelitis suspected cases are notified to the MOPH thru 3 channels: the routine reporting, the hospital weekly zero-reporting and the hospital active sentinel system.
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Case-based investigation |
In order to clarify the etiology of the AFP cases, clinical and laboratory investigation is conducted for each case. The investigation relies on:
- Data collection: related to the clinical findings (asymmetry, rapid progression of the paralysis, presence of fever), the immunization history, the travel history. Cases with fever at onset, rapid progression of the paralysis, paralysis asymmetry and not immunized are pointed as hot cases for being very high suspected as poliomyelitis. Moreover CSF findings as well as EMG results are collected. A specific AFP investigation form is filled by the physician and MOPH.
- Clinical specimen collection: 2 stool specimens (with 24-48 hours apart) are collected from the patient within 14 days of paralysis onset. During this period, the probability to find wild poliovirus (in case of acute poliomyelitis) is greater than 80 %. Cases with no specimen collection or specimen collected after the period of 14 days are designated as �cases with inadequate specimen.
- Follow up at 60 days: of the case in order to assess any residual weakness. The same physician who has diagnosed the case at the beginning conducts the follow up and fills a specific form which is sent to MOPH.
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Specimen management |
Once specimens are collected by the hospital staff or the mother, they are kept, isolated, at cold temperature. Later, specimens are collected by the Epidemiological Surveillance Unit and packaged in ice-boxes (according to WHO recommendations for infectious substance) and shipped to WHO accredited laboratory, VACSERA in Cairo, where they are tested for poliovirus isolation.
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National Expert Group |
Cases with inadequate stool collection or with isolated vaccine strains isolates are reviewed by the National Expert Group (NEG). The functions of NEG are to review AFP cases with:
- Inadequate stool specimen collection in order to classify as compatible poliomyelitis or discarded
- Vaccine poliovirus isolates in order to classify as vaccine poliomyelitis or discarded
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According to the clinical history and exam, the CSF and EMG results, the NEG classifies cases as poliomyelitis compatible or poliomyelitis discarded.
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Case classification |
Lebanon adopts the virological schema classification of WHO.
- AFP cases with adequate stool specimen, collected during the first 14 days of paralysis onset, are classified according to stool culture results as poliomyelitis confirmed or poliomyelitis discarded.
- AFP cases with inadequate stool specimen, collected after the period of the first 14 days of paralysis onset are classified after being reviewed by the National Expert Group.
- Discarded cases are those not due to poliovirus, confirmed cases are those with wild poliovirus isolates and compatible cases are those clinically compatible as poliomyelitis with no laboratory proof.
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