Aspetti entomologici delle malattie trasmesse da zanzare in Italia: sorveglianza dei vettori indigeni e d importazioned

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1 Sistemi di sorveglianza delle zanzare invasive Bologna, 10 marzo 2014 Aspetti entomologici delle malattie trasmesse da zanzare in Italia: sorveglianza dei vettori indigeni e d importazioned Roberto Romi Dipartimento di Malattie Infettive, Parassitarie e Immunomediaete Reparto Malattie Trasmesse da Vettori e Sanità Internazionale Istituto Superiore di Sanità - Roma

2 Malattie trasmesse da vettori (VBD): ruolo svolto dai Culicidi 1) Le zanzare non sono semplici siringhe volanti Molte infezioni sperimentali ottenute forzatamente in laboratorio non hanno alcun riscontro in natura. Perché una specie venga ritenuta vettore di un certo agente patogeno è necessario che siano seguiti precisi criteri epidemiologici

3 Malattie trasmesse da vettori (VBD): ruolo svolto dai Culicidi 2) Le malattie trasmesse da vettori si affrontano combattendo il vettore Esistono circolari Ministeriali, piani di sorveglianza nazionali ed Europei, linee guida locali e internazionali sulle Mosquito Borne Diseases (MBD) emergenti, nella gran parte delle quali manca ogni riferimento agli interventi di controllo Gli interventi di controllo vanno condotti da personale specializzato seguendo protocolli specifici a seconda del vettore, che distinguano anche tra routine ed emergenza. Oltre che seguiti, gli interventi devono essere pianificati (pre) e valutati (post)

4 Vectors of Mosquito Borne Diseases in Italy 65 species of Culicidae have been reported in Italy. These are grouped in 2 sub-families and 8 genera Subfamily Anoph phelinae 1) Anopheles (16 spp) About 1/3 of the species was only sporadically recorded or was no longer reported after the 1950 s 1/3 are rare, un common or strictly associated to peculiar biotopes The remaining 1/3 are common but less than 1/2 of them are very annoiyng species or potential vectors of human pathogens. Up today, 4 species only play a proved role as vectors of human diseases in Italy Subfamily Culicinae 2) Aedes (7 spp) 3) Culex (12 spp) 4) Culiseta (6 spp) 5) Ochlerotatus (20 spp) 6) Ortopodomya (1 sp) 7) Uranotaenia (1 sp) 8) Coquillettidia (2 spp) Ae. albopictus Cx. pipiens s.l. An. Labranchiae, An. superpictus

5 EVENTS RELATED TO MOSQUITO-BORNE DISEASES IN ITALY Ae. atropalpus eradicated 2011 Ae. koreicus Veneto Region 1990 Ae. albopictus widespread Outbreak of Chikugunya fever West Nile Disease A single P.vivax malaria case transmitted by an indigenous vector

6 Uno sguardo al Futuro TODAY WND become an endemic disease Other ARBOv in Italy Introduction of new WN viral USUTU, strain and rise of the number of JEV human cases RVF Unexpected new Tahyna Outbreaks of introduced vectors reported Sindbis DENGUE and CHIK viruses among Indigenous species P. vivax malaria Introduction and establishment Increased number of of invasive allochtonous mosquito gametocyte carriers species

7 Settembre 1990-Settembre Tuttavia, almeno 2 cose le abbiamo IMPARATE : I fattori che determinano l insediamento della specie e la sua abbondanza stagionale sono sostanzialmente 2 te n ue g se rdi n o ve c on one c a, e z v i at olai t i ab i foc a i d g o à l t ipo ibili t La pon dis L e nt i tà e la d e dist lle pr e ribu z cip ione ita zio ann u ni ale

8 Aedes albopictus In Italy 2013: Distribution of Ae.albopictus foci by altitude (meters a.s.l.) Distribution of Ae. albopictus by number of infested Municipalities per Province REGIONS PROVINCES MUNICIPALITIES 20/20 98/110 >3000/8092

9 SUSCEPTIBILITY OF Ae albopictus ITALIAN POPULATIONS TO WNV AND CHIKV Preliminary results of the experimental infection bioassays performed with a membrane-feeder apparatus Aedes albopictus is confirmed to be competent for WNV, although at lower level than Cx. pipiens, and potentially could play a role in the trasmission in urban environments. 10 Italian populations of the species have been infected with Chikungunia virus Preliminary results show a qick rise of the viral titre, an early dissemination in legs and wings and the presence of the virus in the saliva from day 3/6 followed by a quick eclypse of the vira

10 Culex pipiens and the West Nile Disease Several species of Culex genus are considered to be involved in the WNV transmission, but those belonging to the Cx. pipiens s.l. (complex) play the : major role as responsible of the human disease. epizootic cycle enzootic cycle vector reservoir dead-end end host In Europe WNV circulation is confined in both rural and urban ecosystems In sylvatic cycle: wild and wetland birds / ornithophilic mosquito species In urban cycle: In urban cycle: domestic birds / mosquitoes feeding on both birds and humans: as possible bridge-vectors species belonging to Cx. pipiens complex

11 5 years of entomological surveillance whitin the WND National surveillance program selected migratory bird nesting areas 52; 0% 5434; 38% 296; 3% 208; 1% 100; 1% 32; 0% 65; 0% 157; 1% 93; 1% 24; 0% 214; 1% 219; 1% 208; 1% 86; 1% 1704; 12% 6223; 45% 55; 0% 169; 1% 65; 0% larvae 13187; 91% 231; 2% 45; 0% adults Aedes albopictus Anopheles claviger Anopheles maculipennis Anopheles plumbeus Coquillettidia richiardii Culex pipiens Culiseta annulata Culiseta longiareolata Ochlerotatus caspius Ochlerotatus detritus Ochlerotatus rusticus Aedes albopictus Anopheles maculipennis Culex impudicus Culex pipiens Culex hortensis Culiseta annulata Culiseta longiareolata Ochlerotatus caspius Ochlerotatus detritus Ochlerotatus sp. Ochlerotatus zammitii

12 Culex pipiens s.l. Two species, two biological forms or what.? Cx. pipiens pipiens Ornithophilic: feeds predominatly on birds Anautogenous: its oviposition requires a blood meal Eurygamous: mates in open space Epigean habitat: occupies aboveground sites Heterodynamic: undergoes winter diapause Cx. pipiens molestus Mammophilic: : prefers to feed on mammals, including humans Autogenous: able to lay eggs without a blood meal Stenogamous: mates in confined spaces (< 0.1 m 3 ) Hypogean habitat: lives in underground sites Homodynamic: remains active during winter

13 Cx.pipiens s.l. Italian populations Molecular studies CQ11 assay that amplify a flanking region of CQ11 microsatellite (M=molestus form; P=pipiens pipiens form M/P hybrids Most of Cx. pipiens populations analyzed with CQ11 include all three genotypes at different frequencies. Pure Cx. pipiens populations are rare. All three genotypes coexist in simpatry in aboveground habitats, are able to feed both on bird and human (depending on availability), can mate also in confined spaces, when reared in insectary. Only the autogeny seems to be linked with the genetic composition of the population, occurring in population with M and/or M/P; intensity of autogeny is almost directly proportional to M frequency.

14 Comparison between genetic and behavioral features of Cx. pipiens s.l. strains Molestus form (M) Hybrid form (M/P) Pipiens form (P) Unexpected feature

15 Vector competence: susceptibility of Cx. pipiens s.l. to WNV Experimental infection assays of Italian populations using a membrane feeding apparatus. WNV mean viral titre All Cx. pipiens s.l. populations tested resulted susceptible to WNV infection, showing similar trends of viral growth and viral titre. IR = 100% of tested females DR ranging from 47 to 100% TR ranging from 29 to 44%. Even if with different degree of efficiency, all populations resulted able to transmit WNV The PTR of each population was also calculated (range 20-34%) INFECTION RATE (IR) = No with WNV positive abdomen/no tested DISSEMINATION RATE (DR) = No WNV-positive winds+legs/ir TRANSMISSION RATE (TR) = No with WNV/ positive saliva/ir All three genotypes were found infected With WNV, the frequencies depending on the different Population tested. As a consequence, all three genotypes could act as bridge-vectors, being infected and able to bite on humans and birds!? POPULATION TR (PTR) = No WNV-positive saliva/no tested

16 Some other indigenous mosquito species could play a role of arbovirus secondary vector, particularly in rural areas or in the outskirt of the (sub) urban ones Aedes vexans Culex modestus Other Culex spp. Ochlerotatus caspius Culiseta spp. (urban areas too) An. plumbeus

17 Specie indigene: Culiseta longiareolata Specie alloctone invasive: Aedes koreicus BL Culiseta longiareolata è la terza specie più comune in molte aree cittadine dopo Ae. albopictus e Cx. pipiens, con cui spesso condivide i focolai larvali. La specie è prettamente ornitofila ma non disdegna di pungere occasionalmente anche l uomo. In laboratorio si infetta con WNV ma il suo potenziale ruolo di vettore è tutto da studiare. VI TV Da IZS delle Venezie Aedes japonicus BELGIO E OLANDA

18 Aedes aegypti nel Bacino del Mediterraneo Ades aegypti E un vettore più più competente di Ae. albopictus per molti Arbovirus Presenta un maggiore grado endofagia, endofilia e antropofilia L uovo presenta maggiore resistenza al disseccamento ma non al freddo invernale Sopporta meglio gli ambienti Aridi, tuttavia sembra richiedere maggiori risorse trofiche per lo sviluppo larvale YELLOW FEVER and DENGUE outbreaks in the XIX century YF 1804 Alicante, Livorno YF 1821 Barcellona YF 1857 Lisbona YF 1878 Madrid YF was endemic (recurrent?) in ANDALUSIA up to 1880 (12,000 death during the century). DEN DENGUE and Haemorragic DENGUE in GREECE (more than 20,000 cases and 2000 deaths)

19 Sorveglianza e monitoraggio dei Culicidi potenziali vettori di arbovirus LA SORVEGLIANZA ENTOMOLOGICA, insieme a quella epidemiologica Rappresenta i l primo mezzo di prevenzione v ricerca attiva del vettore v survey periodici nei sti a rischio v sistemi e normative di quarantena v valutazione globale (anche passiva) v valutazioni di rischio MONITORAGGIO (routine) v In seguito a reporting passivo v Dinamica e abbondanza stagionali delle popolazioni del vettore v Valutazioni degli interventi di controllo Buona conoscenza dei bionomics dei vettori e metodi differenziati di sorveglianza

20 ENTOMOLOGICAL SURVEILLANCE STRATEGY (for allocthonous invasive species) VECTOR FREE (AT RISK) AREAS Objectives: 1) to prevent the infestait.tion; 2) early detection of the species to eradicate it The maximum effort should be devoted to the monitoring system (passive surveillance ) integrated by targteted surveys in «at risk» areas (active surveillance) To begin data collection activities required after any positive response of the surveillance system. VECTOR POSITIVE AREAS Objectives: 1) risk assessment; 2) to address prevenction and vector control activities Knowledge of the factors that could influence the vector competence of the invasive species determining its vectorial capacity (the real degree of efficiency of the vector): Current status of the infestation (routine monitoring may be reduced to a few number of very informative collection stations) Seasonal dynamic and abundance of the local population (s) - strictly related to Climatic data (in particular the abundance and the distribution of the rainfall during the year) Rate (%) of infection of the vector population (quantitative analysis of field-collected mosquito pools). Bionomics and behavior of the potential vector (lenght of the larval development and gonotrophic cycles, Host preference, expected life duration) Environmental and socio-economical factors (human activities, housing, density of inhabitants, availability of breeding and resting sites)

21 Urban areas, where Culex pipiens and Aedes albopictus often share the same breeding sites Routine monitoring (passive) is carried out according to the bionomics of the 2 speecies by ovitraps and/or BG sentinel for Aedes albopictus CDC light traps, with or without CO2 and/or BG sentinel for Culex pipiens Active surveillance commonly includes larval sampling

22 Esempio dell impatto che le diverse componenti delle attività di controllo possono avere sulle 2 specie, in relazione alla loro biologia e comportamento ATTIVITA Culex pipiens Focolai naturali, artificiali, epigei e ipogei, anche di vaste dimensioni e/o con carica organica elevata. Ciclo di sviluppo più lungo Attività trofica crepuscolare- notturna. Punge sia indoor che outdoor (endo e esofagia) Riposa al chiuso (endofila). Slow feeder. Antilarvali IGR Biologici Source reduction Adulticidi Space spraiyng Tratt. del verde Tratt. murale Zanzariere Repellenti uso topico Repellenti uso topico Aedes albopictus Focolai solamente artificiali. Raccolte d acqua medio-piccole con carica organica modesta Ciclo di sviluppo rapido Attività trofica prevalentemente diurna che si esplica con maggiore intensità outdoor. Riposa all aperto nella vegetazione bassa (esofila). Fast feeder

23 Malaria high receptivity at risk areas and distribution of the main vectors in Italy and location of 2 suspected cases of autochtonous malaria GR ( ) 011) A recent 5-years study (carried out within the EU EDEN project) established a globally very low malariogenic potential for Italy, despite the high receptivity of some areas. 1 Anopheles labranchiae Possible North/eastern expansion of An. Labranchiae (Inner hilly areas) Other members of the An. maculipennis complex mainly zoophylic An. superpictus LT CS Regions with at risk areas cases Proved No risk areas Relatively major risk sporadic P. vivax may occur Moderate risk Very Low Location of the autochtonous cases suspected

24 Mappe di rischio e modelli matematici predittivi sono utili strumenti di prevenzione, ma vanno sempre validati con l esperienza l di campo Chikungunia coutries or areas at risk. WHO Dengue countries or areas at risk. WHO Tanto per dimostrare quanto sia difficile creare modelli matematici e realizzare mappe di rischio affidabili (spesso basate solo su dati climatici), nella tarda estate dell Anno seguente si è verificato l outbreak di febbre da Chik virus in provincia di Ravenna e nel i casi di dengue autoctoni in Francia e Croazia.

25 GRAZIE DELL ATTENZIONE