Daniela Boccolini1, Michela Menegon2, Marco Di Luca2, Luciano Toma2, Francesco Severini2, Gianluca Marucci2, Stefania D'Amato3, Anna Caraglia4, Francesco Paolo Maraglino3, Giovanni Rezza2, Roberto Romi2, Luigi Gradoni2, Carlo Severini5. 1. Dipartimento Malattie Infettive, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy. daniela.boccolini@iss.it. 2. Dipartimento Malattie Infettive, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy. 3. Ministero della Salute, Direzione Generale della Prevenzione Sanitari, Ufficio 5 - Prevenzione delle Malattie Trasmissibili e Profilassi Internazionale, Rome, Italy. 4. Ministero della Salute, Direzione Generale della Prevenzione Sanitaria, Ufficio 1 - Affari generali e segreteria tecnico-organizzativa, Rome, Italy. 5. Dipartimento Malattie Infettive, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy. carlo.severini@iss.it.
Abstract
BACKGROUND: The European region achieved interruption of malaria transmission during the 1970s. Since then, malaria control programs were replaced by surveillance systems in order to prevent possible re-emergence of this disease. Sporadic cases of non-imported malaria were recorded in several European countries in the past decade and locally transmitted outbreaks of Plasmodium vivax, most probably supported by Anopheles sacharovi, have been repeatedly reported from Greece since 2009. The possibility of locally-transmitted malaria has been extensively studied in Italy where the former malaria vector An. labranchiae survived the control campaign which led to malaria elimination. In this study, we present paradigmatic cases that occurred during a 2017 unusual cluster, which caused strong concern in public opinion and were carefully investigated after the implementation of the updated malaria surveillance system. METHODS: For suspected locally-transmitted malaria cases, alerts to Ministry of Health (MoH) and the National Institute of Health (ISS) were mandated by the Local Health Services (LHS). Epidemiological investigations on the transmission modes and the identification of possible infection's source were carried out by LHS, MoH and ISS. Entomological investigations were implemented locally for all suspected locally-transmitted cases that occurred in periods suitable to anopheline activity. Molecular diagnosis by nested-PCR for the five human Plasmodium species was performed to support microscopic diagnosis. In addition, genotyping of P. falciparum isolate was carried out to investigate putative sources of infection and transmission modalities. RESULTS: In 2017, a cluster of seven non-imported cases was recorded from August through October. Among them, P. ovale curtisi was responsible of one case whereas six cases were caused by P. falciparum. Two cases were proved to be nosocomial while the other five were recorded as cryptic at the end of epidemiological investigations. CONCLUSIONS: The epidemiological evidence shows that the locally acquired events are sporadic, often remain unresolved and classified as cryptic ones despite investigative efforts. The "cluster" of seven non-imported cases that occurred in 2017 in different regions of Italy therefore represents a conscious alert that should lead us to maintain a constant level of surveillance in a former malaria endemic country.
BACKGROUND: The European region achieved interruption of malaria transmission during the 1970s. Since then, malaria control programs were replaced by surveillance systems in order to prevent possible re-emergence of this disease. Sporadic cases of non-imported malaria were recorded in several European countries in the past decade and locally transmitted outbreaks of Plasmodium vivax, most probably supported by Anopheles sacharovi, have been repeatedly reported from Greece since 2009. The possibility of locally-transmitted malaria has been extensively studied in Italy where the former malaria vector An. labranchiae survived the control campaign which led to malaria elimination. In this study, we present paradigmatic cases that occurred during a 2017 unusual cluster, which caused strong concern in public opinion and were carefully investigated after the implementation of the updated malaria surveillance system. METHODS: For suspected locally-transmitted malaria cases, alerts to Ministry of Health (MoH) and the National Institute of Health (ISS) were mandated by the Local Health Services (LHS). Epidemiological investigations on the transmission modes and the identification of possible infection's source were carried out by LHS, MoH and ISS. Entomological investigations were implemented locally for all suspected locally-transmitted cases that occurred in periods suitable to anopheline activity. Molecular diagnosis by nested-PCR for the five humanPlasmodium species was performed to support microscopic diagnosis. In addition, genotyping of P. falciparum isolate was carried out to investigate putative sources of infection and transmission modalities. RESULTS: In 2017, a cluster of seven non-imported cases was recorded from August through October. Among them, P. ovale curtisi was responsible of one case whereas six cases were caused by P. falciparum. Two cases were proved to be nosocomial while the other five were recorded as cryptic at the end of epidemiological investigations. CONCLUSIONS: The epidemiological evidence shows that the locally acquired events are sporadic, often remain unresolved and classified as cryptic ones despite investigative efforts. The "cluster" of seven non-imported cases that occurred in 2017 in different regions of Italy therefore represents a conscious alert that should lead us to maintain a constant level of surveillance in a former malaria endemic country.
Authors: Arianna Forniti; Niccolò Riccardi; Pietro Sponga; Chiara Buono; Riccardo Iapoce; Lorenzo Roberto Suardi; Giusy Tiseo; Marco Falcone; Francesco Menichetti Journal: Infez Med Date: 2022-06-01