CONTRIBUTO AL PROGETTO OMS DI ERADICAZIONE DELLA POLIOMIELITE: RISULTATI DELLE ATTIVITÀ DI SORVEGLIANZA IN LOMBARDIA.
Tesi di Dottorato
Data di Pubblicazione:
2016
Citazione:
CONTRIBUTO AL PROGETTO OMS DI ERADICAZIONE DELLA POLIOMIELITE: RISULTATI DELLE ATTIVITÀ DI SORVEGLIANZA IN LOMBARDIA / L. Pellegrinelli ; tutor: S. Binda ; coordinatore: E. Tanzi. DIPARTIMENTO DI SCIENZE BIOMEDICHE PER LA SALUTE, 2016 Jan 25. 28. ciclo, Anno Accademico 2015. [10.13130/l-pellegrinelli_phd2016-01-25].
Abstract:
A contribution to the WHO global polio eradication initiative: the results of surveillance activities in Lombardy (Northern Italy), 2012-2015.
Although in 2015 poliovirus (PV) transmission has been reported at the lowest levels ever recorded, the virus is still endemic in two countries – Afghanistan and Pakistan. Until PV transmission is interrupted in these countries, all countries remain at risk of virus importation - especially vulnerable countries with weak public health and immunization services and travel or trade links to endemic countries. The high levels of immigration flows across the Mediterranean Sea jeopardize Italy for PV reintroduction.
The “WHO Strategic Plan of the Global Polio Eradication Initiative” indicates the nationwide surveillance of Acute Flaccid Paralysis (AFP) as the gold standard for detecting cases of poliomyelitis. In addition, systematic Environmental Surveillance (ES), seeking the presence of PV in sewage, is recognized as a powerful tool to confirm PV circulation in absence of AFP cases, especially in polio-free countries. In Italy, nationwide AFP surveillance has been set up in 1997, and ES has been established since 2005 in Milan and other five Italian cities (Bolzano, Parma, Sassari, Napoli and Palermo).
This PhD project aimed at evaluating these two public health surveillance systems ongoing in Lombardy (Northern Italy) in the period spanning from 2012 to 2015, in order to improve their quality and efficiency, and to achieve the WHO criteria. The results of surveillance activities were described and the assessment of system attributes (including data quality, sensitivity and timeliness) were discussed. Additionally, in the framework of the ES, the circulation and characterization of non-polio Enterovirus (NPEV) was evaluated in the study population.
The surveillance activities were carried out according to WHO guidelines from January 2012 to October 2015. For AFP surveillance, all children <15 years who met the WHO definition of AFP case were enrolled, and the collection of stool and serum samples from each case was requested. For ES, wastewater samples were collected twice a month at the intel of 3 wastewater treatment plants located in Milan. Stool specimens collected from AFP cases and wastewater samples were analyzed to detect PV and NPEVs by virus isolation in RD (human rhabdomyosarcoma) and L20B (murine transgenic L cells) cell cultures, and by PCR assay specific for the 5′ noncoding region [5′NCR] (nucleotide [nt]: 179-575). The identified viruses were genotyped by sequence analysis of the VP1 gene (nt. 2602-2977).
In order to define the serological status/immunity against PV, serum samples collected from AFP cases were analyzed by microneutralization assay against PV1, PV2, and PV3. According to WHO, an antibody titre >1:8 was considered protective.
From January 2012 to October 2015, 52 AFP cases were reported in Lombardy with an incidence rate of 1.04/100’000 children <15 years of age. The median age of AFP cases was 5.8 years [inter-quartile range (IQR): 10.0 years]; no gender difference was observed. The annual incidence rates were 0.8/100’000 in 2012, 1.5/100’000 in 2013, 1.1/100’000 in 2014, and 0.6/100’000 in 2015 (preliminary data up to October). According to the WHO, the sensitivity of the AFP surveillance system is considered adequate when at least one case of AFP is detected annually per 100’000 children aged less than 15 years. As in 2012 the sensitivity of the surveillance system did not met this criterion, several interventions were implemented to raise awareness among the parts involved in the surveillance. On purpose, reports on the AFP notified weekly by sentinel hospitals were sent out quarterly to all physicians involved in the su
Tipologia IRIS:
Tesi di dottorato
Keywords:
Poliovirus; poliomielite; sorveglianza delle Paralisi Flaccide Acute; sorvgelianza Ambientale di poliovirus ed anterovirus-non polio; Global Polio Eradication Initiative
Elenco autori:
L. Pellegrinelli
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