The number of reported AFP cases was relatively higher during the summer months due to higher enterovirus activity. However, the incidence of AFP mainly reflects the incidence of GBS. Data on GBS prevalence at specific seasons are conflicting [36, 37]. Most studies suggest that this syndrome occurs sporadically with no significant variation over time [23, 24]. Adequate virological examination was performed in more than 90% of patients (Table 2). Isolation of the virus from feces or throat swabs was successful in at least 5% of patients. The WHO target for the isolation rate of non-polio enteroviruses is 10%[5]. This indicator has consistently remained below the acceptable rate in our country in recent years (Table 2). According to the updated polio laboratory network, “a major change in 2000 was the substitution of poliovirus-specific L20B cells with NPEV-sensitive Hep2 cells in national polio reference laboratories. Since NPEV isolation now depends solely on DR cells, annual rates for most laboratories are expected to be lower than in previous years. The lower value is not yet clear.[38] The NPEV rate is no longer a strict criterion for the accreditation of reference laboratories, as the isolation rate is influenced by various factors such as season, altitude or hygiene of the population[39].
However, the rate can be a useful indicator of laboratory performance. Therefore, it is necessary to improve the virological culture technique of patients with AFP in our country. Other performance indicators met WHO criteria for AFP rate, timeliness of reporting, and adequate epidemiological investigations (Table 2). These indicators showed the effectiveness of the AFP monitoring programme in Kurdistan. Environmental monitoring involves testing wastewater or other environmental samples for the presence of poliovirus. Environmental surveillance often confirms wild poliovirus infections in the absence of paralysis. Systematic environmental sampling (e.g. Egypt and Mumbai, India) provides important complementary monitoring data.
Ad hoc environmental surveillance elsewhere (particularly in polio-free areas) provides a better understanding of the international spread of poliovirus. Spatial distribution of AFP cases by final virological classification, Kenya, 2016-2018 The forty-first World Health Assembly (WHA) held in Geneva, Switzerland, in May 1988 marked a breakthrough in the launch of the Global Polio Eradication Initiative (GPEI), organized by national governments in partnership with the World Health Organization (WHO), The Rotary Foundation, the Bill & Melinda Gates Foundation (BMGF), the U.S. Centers for Disease Control (CDC), and the United Nations Children`s Fund. (UNICEF) [5, 8, 12]. The goal of the initiative was to eradicate poliovirus worldwide by the year 2000 using four proven strategies [13]. These include: 1) maintaining high population immunity to OPV and IPV through the Expanded Programme on Immunization (EPI), 2) detecting and disrupting the circulation of all suspected polio cases through sensitive AFP surveillance, 3) supplemental immunization activities (SIAs), and 4) clean-up campaigns [14, 15]. A sensitive AFP surveillance system is at the heart of the overall polio eradication initiative [4, 16]. The GPEI has a set of performance indicators to monitor progress and assess countries` performance [1]. These global efforts have reduced the number of UPV cases by more than 99%: from approximately 350,000 UPU cases in 125 countries in 1988 to only 33 cases at the end of 2018 [17, 18]. Since August 2016, no cases of FYV have been detected outside Afghanistan and Pakistan [17,18,19]. Probable case: a case where AFP is detected and no other cause of paralysis can be identified immediately. The classification of “probable case” is also temporary; Within 10 weeks of onset, the case should be classified as confirmed, “compatible”, “vaccine-associated” or “discarded”.
Monitoring acute flaccid paralysis (AFP) is a key strategy for monitoring progress in polio eradication and a sensitive measure to detect potential cases of polio and poliovirus infection. This study was conducted to describe the characteristics of patients reported with AFP and to assess the performance of the surveillance system in Kurdistan Province, western Iran, using indicators recommended by the World Health Organization (WHO). Since the 1988 World Health Assembly resolution on polio eradication, the number of polio-endemic countries has decreased from 125 in 1988 to six by the end of 2003 (1). As part of the eradication strategy, a global surveillance system was established to 1) identify cases of acute flaccid paralysis (AFP) in children aged <15 years and 2) use a network of accredited laboratories to perform virological testing on stool samples to determine if paralysis is due to poliovirus infection. As AFP surveillance systems evolved, countries increasingly adopted AFP surveillance strategies and infrastructures to detect other diseases (2). This report describes the status of global AFP surveillance, including its expansion or use as a model in 131 (66%) of 198 countries for reporting measles and other vaccine-preventable diseases. As polio is eradicated, AFP surveillance systems in these and other countries could be further expanded and adapted to improve detection and response to other diseases. Vaccine-associated paralytic poliomyelitis case: Acute paralytic disease in which vaccine-like polioviruses are isolated from stool specimens and the virus is considered the cause of the disease.
There are two possible types of vaccine-associated paralytic polio (VLP): recipient and contact. A case classified as a recipient is an individual who has AFP 4 to 40 days after the onset of OPV and has neurological sequelae consistent with poliomyelitis 60 days after the onset of paralysis. A case is classified as contact AVC if a person with residual paralysis 60 days after the onset of AFP was in contact with a person who received OPV between 4 and 85 days before the start of contact 40 to 40 days before the onset of contact. First, a questionnaire was designed based on the data recommended in the WHO guidelines[5]. The case definition (of what needs to be reported) has been integrated and clearly defined. WHO has defined AFP as “any child under 15 years of age with acute focal weakness or paralysis (including GBS)” or anyone with paralytic disease at any age where poliomyelitis is suspected, characterized by flaccid (reduced tone), without other obvious causes (p. e.g. trauma) [5, 9].
Transient weaknesses such as postictal weakness should not be reported as AFP[11]. Patient demographics, assessment, diagnosis, follow-up and laboratory results were included in the questionnaire. All documents, including copies of patient records, laboratory results, imaging and electrodiagnostic assessments (electromyography [EMG] and nerve conduction velocity studies [NCS]), even if performed in other hospitals, have been collected in a proprietary file. Case data (to be linked to sample-based data for analysis): (i) unique identifier; (ii) the name of the geographical area (district and province); (iii) date of birth; (iv) the date of onset of paralysis; (v) the date of notification; (vi) the date of the investigation; (vii) Total doses of polio vaccine received; (viii) fever at the onset of paralysis; ix) progression of paralysis within 4 days; (x) asymmetric paralysis; (xi) the date of the 60-day follow-up; (xii) findings after 60 days of follow-up; (xiii) Final ranking. The authors would like to thank all stakeholders who contributed directly or indirectly to strengthening polio eradication activities in Kenya, especially those involved in reporting, investigating and managing case data used in our analysis. The results of the study showed that the median proportion of AFP cases with appropriate samples exceeded the WHO-recommended target of 80% and above from 2016 to 2018. As with the NP-AFP rate, there were differences in the proper performance of the Chair between counties. The districts of Lamu, West Pokot, Marsabit, Turkana, Siaya, Garissa and Busia were unable to meet the WHO-recommended target of collecting two appropriate samples within 14 days of the onset of paralysis.
