Cristina Khoury

Host preferences of phlebotomine sand flies at a hypoendemic focus of canine leishmaniasis in central Italy

A survey was carried out on phlebotomine sand flies and their feeding habits at a hypoendemic focus of Leishmania infantum in Macerata province, central Italy. During two consecutive years (2000-2001), 1465 sand fly specimens (42.5% of which were males) were collected from a variety of diurnal resting sites in the municipality of Camerino. The most prevalent species was Phlebotomus perniciosus (76.6%), followed by P. papatasi (10.4%), Sergentomyia minuta (9.1%), Phlebotomus perfiliewi (3.3%) and P. mascittii (0.5%). Among the 842 females collected, 578 (68.6%) were blood-fed. Based on the results of blood meal analyses, P. perniciosus fed on man, dogs, equines, sheep and birds; P. perfiliewi on dogs, equines, sheep and birds; P. papatasi on dogs, equines and birds. Two specimens of P. mascittii fed on equines. Forage ratios (FRs) and host selectivity indices gave different results for the large domestic animals. More than 95% of the specimens collected inside a stable, dog kennel, sheep pen and chicken house were found to have fed on the animals housed in the respective shelters. In addition, at one collecting site where almost all the hosts mentioned above were present simultaneously, both P. perniciosus and P. perfiliewi were found to have fed on all five species, indicating that host choice was probably related to its availability (i.e. number and size) rather than specific attractiveness. The feeding habits of the two Leishmania vectors may have implications for the epidemiology of leishmaniasis in urban and peri-urban areas, where sand fly females deprived of other vertebrate hosts (particularly the larger species) may begin to bite humans and dogs more frequently.

Seasonal Dynamics of Phlebotomine Sand Fly Species Proven Vectors of Mediterranean Leishmaniasis Caused by Leishmania infantum.

Background The recent geographical expansion of phlebotomine vectors of Leishmania infantum in the Mediterranean subregion has been attributed to ongoing climate changes. At these latitudes, the activity of sand flies is typically seasonal; because seasonal phenomena are also sensitive to general variations in climate, current phenological data sets can provide a baseline for continuing investigations on sand fly population dynamics that may impact on future scenarios of leishmaniasis transmission. With this aim, in 2011–2013 a consortium of partners from eight Mediterranean countries carried out entomological investigations in sites where L. infantum transmission was recently reported. Methods/Principal Findings A common protocol for sand fly collection included monthly captures by CDC light traps, complemented by sticky traps in most of the sites. Collections were replicated for more than one season in order to reduce the effects of local weather events. In each site, the trapping effort was left unchanged throughout the survey to legitimate inter-seasonal comparisons. Data from 99,000 collected specimens were analyzed, resulting in the description of seasonal dynamics of 56,000 sand flies belonging to L. infantum vector species throughout a wide geographical area, namely P. perniciosus (Portugal, Spain and Italy), P. ariasi (France), P. neglectus (Greece), P. tobbi (Cyprus and Turkey), P. balcanicus and P. kandelakii (Georgia). Time of sand fly appearance/disappearance in collections differed between sites, and seasonal densities showed variations in each site. Significant correlations were found between latitude/mean annual temperature of sites and i) the first month of sand fly appearance, that ranged from early April to the first half of June; ii) the type of density trend, varying from a single peak in July/August to multiple peaks increasing in magnitude from May through September. A 3-modal trend, recorded for P. tobbi in Cyprus, represents a novel finding for a L. infantum vector. Adults ended the activity starting from mid September through November, without significant correlation with latitude/mean annual temperature of sites. The period of potential exposure to L.infantum in the Mediterranean subregion, as inferred by adult densities calculated from 3 years, 37 sites and 6 competent vector species, was associated to a regular bell-shaped density curve having a wide peak center encompassing the July-September period, and falling between early May to late October for more than 99% of values. Apparently no risk for leishmaniasis transmission took place from December through March in the years considered. We found a common pattern of nocturnal females activity, whose density peaked between 11 pm and 2 am. Conclusions Despite annual variations, multiple collections performed over consecutive years provided homogeneous patterns of the potential behavior of leishmaniasis vectors in selected sites, which we propose may represent sentinel areas for future monitoring. In the investigated years, higher potential risk for L. infantum transmission in the Mediterranean was identified in the June-October period (97% relative vector density), however such risk was not equally distributed throughout the region, since density waves of adults occurred earlier and were more frequent in southern territories.

Ticks Infesting Livestock on Farms in Western Sicily, Italy

The results of a 2-year survey on ticks infesting livestock on farms in Western Sicily, Italy, are reported. Several dogs living in the same area were also examined for ticks. Moreover, free-living ticks from one cattle farm were caught by CO2 traps and flagging. A total of 6208 specimens was collected belonging to 9 species: Rhipicephalus bursa (32.4%), Rhipicephalus turanicus (22.7%), Rhipicephalus sanguineus (19.3%), Hyalomma lusitanicum (12.0%), Haemaphysalis punctata (7.8%), Hyalomma marginatum (3.5%), Dermacentor marginatus (1.4%), Ixodes ricinus (0.8%) and Ixodes hexagonus (0.1%). The species belonging to the genus Rhipicephalus were present on all hosts and habitats monitored, R. bursa was found to be abundant on cattle (46.3%) and sheep (62.0%), R. sanguineus was prevalent on dogs (50.4%), and R. turanicus on donkeys (41.0%) and as free-living species (48.5%).

Environmental correlates of crimean-congo haemorrhagic fever incidence in Bulgaria

BackgroundCrimean-Congo Haemorrhagic Fever (CCHF) is a zoonotic viral disease transmitted by ixodid tick bites, mainly of Hyalomma spp., or through contact with blood/tissues from infected people or animals. CCHF is endemic in the Balkan area, including Bulgaria, where it causes both sporadic cases and community outbreaks.MethodsWe described trends of CCHF in Bulgaria between 1997 and 2009 and investigated the associations between CCHF incidence and a selection of environmental factors using a zero-inflated modelling approach.ResultsA total of 159 CCHF cases (38 women and 121 men) were identified between 1997 and 2009. The incidence was 0.13 cases per 100,000 population/year with a fatality rate of 26%. An epidemic peak was detected close to the Turkish border in the summer of 2002. Most cases were reported between April and September. Increasing mean temperature, Normalized Difference Vegetation Index (NDVI), savannah-type land coverage or habitat fragmentation increased significantly the incidence of CCHF in the CCHF-affected areas. Similar to that observed in Turkey, we found that areas with warmer temperatures in the autumn prior to the case-reporting year had an increased probability of reporting zero CCHF cases.ConclusionsWe identified environmental correlates of CCHF incidence in Bulgaria that may support the prospective implementation of public health interventions.

Ecological Niche Modelling of Potential West Nile Virus Vector Mosquito Species and Their Geographical Association with Equine Epizootics in Italy

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.

Prevalence of tick-borne pathogens in an urban park in Rome, Italy

INTRODUCTION Limited information is available about the presence of tick-borne pathogens in urban parks in Italy. To fill this gap, ticks were collected in a public park in Rome over a 1-year period and screened by molecular methods for tick-borne pathogens. RESULTS AND CONCLUSION The most abundant tick species were Rhipicephalus turanicus and Ixodes ricinus. The predominant pathogens detected were Borrelia. burgdorferi sensu lato (36%), Rickettsia spp. (36%), and Coxiella burnetii (22%). Among less frequently detected pathogens, Babesia microti was detected for the first time in Italy, with a prevalence of 4%. Neither Bartonella spp. nor Francisella tularensis were detected. With regard to co-infections, the most frequent double and triple infections involved Rickettsia spp., B. burgdorferi sl., and C. burnetii.. A positive correlation was detected between pathogens and I. ricinus. Further studies are needed in order to assess risk associated with tick-borne pathogens in urban areas.

Ultrastructure of reproductive accessory glands in the female sandfly Phlebotomus perniciosus Newstead (Diptera : Psychodidae)

Abstract The paired female accessory glands of Phlebotomus perniciosus (Diptera : Psychodidae) were investigated by light microscopy, and by scanning and transmission electron microscopy. These glands undergo morphological and functional changes during oocyte development. After the blood meal, the monostratified glandular epithelium differentiates and starts to secrete. Well-developed rough endoplasmic reticulum, Golgi complexes, and membrane-bounded exocytic vesicles suggest that these secretory cells are involved in protein synthesis. As the secretory cells differentiate, the glandular lumen increases in size and fills with secretory material, consisting of globular granules of different sizes in an amorphous electron-dense matrix. The granules have an electron-translucent core and an electron-dense cortex. The morphological characteristics of the glandular epithelium and the functional role of the glands are discussed in relation to their possible contribution to the reproductive process.

Characterization of spotted fever group Rickettsiae in ticks from a city park of Rome, Italy

BACKGROUND Ticks are vectors and important reservoirs for microbial agents that cause disease in humans and animals. Among these pathogens, the members of Rickettsia species play an important role in public health. AIM AND METHODS One hundred twenty-nine ticks belonging to four tick species (Ixodes ricinus, Rhipicephalus turanicus, Dermacentor marginatus, and Haemaphysalis punctata) were collected at different sites of the Insugherata Natural Reserve, localized in the urban area of Rome, Italy. Questing ticks were tested by PCR for Rickettsia spp., amplifying partial gene of ompA. RESULTS Forty-six ticks were found to be infected with Rickettsia species. Five SFG rickettsiae were identified: three human pathogens Rickettsia conorii, Rickettsia massiliae and Rickettsia aeschlimannii, and two putative new strains Rickettsia sp. strain RM1 and Rickettsia sp. strain RM2. The phylogenetic analysis of partial gene sequences of ompA, gltA, and 17-kd antigen showed that they clustered with several rickettsiae with unidentified pathogenicity. However, Rickettsia sp. strain RM1 and Rickettsia sp. strain RM2 clustered in a statistically supported clade with R. massiliae, and R. monacensis, respectively. CONCLUSION Our findings suggest that Rickettsia species other than R. conorii are implicated in human disease in Italy.

Seasonal dynamics of tick species in an urban park of Rome

Regular collections were obtained in the Natural Reserve of the Insugherata of Rome during 2011 in order to obtain the tick species composition and the respective seasonal dynamics of the area. A total of 325 ticks was collected in selected sites by means of drag sampling. Among the identified species, Rhipicephalus turanicus was the most abundant (72.3%), followed by Ixodes ricinus (19.7%), Dermacentor marginatus (6.5%), Haemaphysalis punctata (1.2%), and Rhipicephalus bursa (0.3%). R. turanicus occurred mainly in pastures, showing a mono-modal seasonal activity pattern from spring to early summer. Questing I. ricinus were prevalent in woodland from October to May, and the seasonal trend of specimens showed a weak peak in winter. Although adult D. marginatus exhibited seasonal dynamics similar to I. ricinus, with an activity period from October to April, this species occurred in a different environment (pasture) and with considerably lower densities. Haemaphysalis punctata and R. bursa were rare, with an apparent autumn and autumn-winter seasonal activity, respectively. While the species diversity recorded appears as an unequivocal consequence of the natural state of the park, the remarkable R. turanicus density could be a direct effect of the recent introduction of wild boar, as carriers, from the close Veio Park. The presence of the species, a proven vector of various diseases in humans and domestic animals, is discussed in the light of the possible risk of tick-bite exposure of park workers and visitors.

Preliminary investigation on tick fauna in the neighborhood of Tarquinia, Lazio, Italy

INTRODUCTION This study represents a preliminary inquiry on tick fauna composition carried out in Maremma, Central Italy, where very few data are available. MATERIALS AND METHODS The study area was selected in the limestone hills surrounding Tarquinia town, on the base of suitable elements directly affecting the tick occurrence and the possible circulation of tick-borne pathogens, such as wild cattle rearing, kind of vegetation and human activities. Since a proper understanding of tick ecology is critical in predicting the risk of tick-borne pathogen transmission in a given area, a series of surveys was planned in such area in 2011. RESULTS One hundred fifty-four ticks belonging to 4 genera and 6 species, namely Ixodes ricinus (n. = 109; 70%), Rhipicephalus bursa (n. = 18; 12%), Rhipicephalus turanicus (n. = 14; 9%), Rhipicephalus sanguineus (n. = 6; 4%), Hyalomma marginatum (n. = 4; 3%) and Dermacentor marginatus (n. = 3; 2%) were identified and reported for the area. DISCUSSION The results of this acarological research represent a significant contribution to the knowledge of the tick fauna of rural areas in Northern Lazio Region, as first step toward a future molecular investigation on pathogen circulation.