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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.

In 2017, a chikungunya outbreak in central Italy later evolved into a secondary cluster in southern Italy, providing evidence of disease emergence in new areas. Officials have taken action to raise awareness among clinicians and the general population, increase timely case detection, reduce mosquito breeding sites, and promote mosquito bite prevention.

Background: Chikungunya virus (CHIKV) is an emerging arbovirus, belonging to the Togaviridae family, Alphavirus genus, transmitted by Aedes spp. mosquitoes. Since 2007, two different CHIKV strains (E1-226A and E1-226V) have been responsible for outbreaks in European countries, including Italy, sustained by Ae. albopictus mosquitoes., Findings: In this study, we assessed the susceptibility to the CHIKV E1-226V, strain responsible for the Italian 2007 outbreak, of eight Ae. albopictus populations collected in Northern, Central, Southern, and Island Italy, by experimental infections. Vector competence was evaluated by estimating infection, dissemination, and transmission rates (IR, DR, TR), through detection of the virus in the bodies, legs plus wings, and saliva, respectively. Additionally, vertical transmission was evaluated by the detection of the virus in the offspring. The results of our study demonstrated that the Italian populations of Ae. albopictus tested were susceptible to CHIKV infection, and can disseminate the virus outside the midgut barrier with high values of IR and DR. Viral infectious RNA was detected in the saliva of three populations from Central, Southern, and Island Italy, also tested for TR and population transmission rate (PTR) values. No progeny of the first and second gonotrophic cycle were positive for CHIKV., Conclusions: This study strongly confirms the role of Ae. albopictus as a potential CHIKV vector in Italy. This may represent a threat, especially considering both the high density of this species, which is widespread throughout the country, and the increasing number of cases of imported arboviruses.

An autochthonous chikungunya outbreak is ongoing near Anzio, a coastal town in the province of Rome. The virus isolated from one patient and mosquitoes lacks the A226V mutation and belongs to an East Central South African strain. As of 20 September, 86 cases are laboratory-confirmed. The outbreak proximity to the capital, its late summer occurrence, and diagnostic delays, are favouring transmission. Vector control, enhanced surveillance and restricted blood donations are being implemented in affected areas.

In Italy, West Nile virus (WNV) equine outbreaks have occurred annually since 2008. Characterizing WNV vector habitat requirements allows for the identification of areas at risk of viral amplification and transmission. Maxent-based ecological niche models were developed using literature records of 13 potential WNV Italian vector mosquito species to predict their habitat suitability range and to investigate possible geographical associations with WNV equine outbreak occurrence in Italy from 2008 to 2010. The contribution of different environmental variables to the niche models was also assessed. Suitable habitats for Culex pipiens, Aedes albopictus, and Anopheles maculipennis were widely distributed; Culex modestus, Ochlerotatus geniculatus, Ochlerotatus caspius, Coquillettidia richiardii, Aedes vexans, and Anopheles plumbeus were concentrated in north-central Italy; Aedes cinereus, Culex theileri, Ochlerotatus dorsalis, and Culiseta longiareolata were restricted to coastal/southern areas. Elevation, temperature, and precipitation variables showed the highest predictive power. Host population and landscape variables provided minor contributions. WNV equine outbreaks had a significantly higher probability to occur in habitats suitable for Cx. modestus and Cx. pipiens, providing circumstantial evidence that the potential distribution of these two species coincides geographically with the observed distribution of the disease in equines.