Simona Gabrielli

First finding of Dirofilaria repens in a natural population of Aedes albopictus

Abstract.  The invasive mosquito Aedes albopictus (Skuse) (Diptera: Culicidae) has become widespread in Italy during the past decade. Also Italy has foci of canine filariasis caused by Dirofilaria (Spirurida: Onchocercidae), due to subcutaneous D. repens Railliet & Henry as well as the dog heartworm D. immitis (Leidy) transmitted by various vector mosquitoes (Diptera: Culicidae). In 2002, at Fiumicino, west of Rome (Lazio Region), 17% of dogs were found to have D. repens microfilariae in peripheral blood. To evaluate the role of Ae. albopictus as a vector of Dirofilaria in this area, female mosquitoes were collected daily, June–October 2002, landing on dog or human bait in a rural house at Focene. Mosquitoes were maintained at 27°C and 70% RH for 6 days, to allow development or purging of filaria larvae, then identified and frozen for subsequent molecular assay with filaria‐specific ribosomal S2‐S16 primers. To distinguish specimens harbouring infective L3 Dirofilaria larvae, DNA was extracted separately from the mosquito abdomen and head‐thorax. Dirofilaria species were identified by sequencing, confirmed by polymerase chain reaction of positive specimens using primers specific for D. immitis and D. repens. Dirofilaria DNA was detected in 3/154 (2%) of Ae. albopictus females examined: D. repens DNA in head‐thorax and abdomen of one collected 27th July; D. immitis in the abdomen of one collected 24th September; DNA of both D. immitis and D. repens in the head‐thorax of one collected 11th October 2002. Thus Ae. albopictus is a potential vector of both Dirofilarias in Italy, representing risks for veterinary and human health.

Searching for Wolbachia (Rickettsiales: Rickettsiaceae) in Mosquitoes (Diptera: Culicidae): Large Polymerase Chain Reaction Survey and New Identifications

Abstract Bacteria of the genus Wolbachia constitute a group of intracellular and maternally inherited micro-organisms that are widespread in arthropods, inducing several reproductive disorders such as cytoplasmic incompatibility in their hosts. Considering relevant biological implications related to the presence of Wolbachia in several insect orders, for example its potential role as mechanism for rapid speciation and as vehicle to drive genetic markers in wild populations of vectors of medical and veterinary interest, we carried out an extensive polymerase chain reaction survey to detect Wolbachia in several species of mosquito belonging to genera involved in the transmission of pathogens. Five species out of 26 tested have shown to be infected; for four of them this is the first evidence of the Wolbachia infection. A phylogenetic analysis was also performed, positioning the five Wolbachia strains in the phyletic subdivision B.

Prevalence and diagnosis of Babesia and Theileria infections in horses in Italy: a preliminary study.

Babesia caballi and Theileria equi are the causative agents of equine piroplasmosis. In this preliminary epidemiological study, 412 horses reared in central and northern Italy were sampled and three diagnostic methods compared, namely, the microscopy, the indirect fluorescent antibody test (IFAT) and a PCR. Possible risk factors (such as area, season, breed, activity, sex, age, and grazing) associated with serological positivity were evaluated. A seroprevalence of 68.4% was found: 12.4% of the animals had anti-T. equi antibodies, 17.9% anti-B. caballi antibodies and 38.1% had antibodies against both species. Of the seropositive samples, 3.1% and 9.4% were positive to microscopy and PCR, respectively; 31.5% of the horses were IFAT-negative but 1.4% and 2.4% of the corresponding blood samples were positive to microscopy and PCR, respectively. Molecular techniques revealed that the species present were closely related to T. equi, Theileria sergenti, Theileria buffeli and the Babesia microti-like piroplasm provisionally named Theileria annae. Grazing was found to be a pronounced risk factor for equine piroplasmosis.

Natural Vectors of Dirofilariasis in Rural and Urban Areas of the Tuscan Region, Central Italy

Abstract Entomological investigations by means of dog- and human-baited traps were carried out in summers 2000–2002 in urban and rural areas of the Tuscan region in central Italy. The aim of the study was to define the mosquito species involved in the transmission of Dirofilaria nematodes and to assess the risk that their presence might represent for animal and human health. Nocturnal fieldwork on host-seeking activity and feeding preferences was followed by microscopic identification of the mosquito species attracted and by molecular identification of Dirofilaria parasites in mosquitoes. In total, 3,611 mosquito females belonging to 12 species, largely represented by Culex pipiens L. and Aedes caspius (Pallas), were caught. Some females of each species collected fed on the dogs, indicating their possible role as an intermediate host, but filarial DNA was found only in Cx. pipiens, Anopheles maculipennis s.l. (Meigen), and Coquillettidia richiardii (Ficalbi). In rural environments, the DNA evidence indicated the presence of infective larvae of Dirofilaria immitis, whereas in urban areas, infective larvae of Dirofilaria repens were present. The role of Cx. pipiens as a vector for heartworm disease and subcutaneous infections in natural and artificial environments was confirmed, whereas Ae. caspius seemed refractory to the infection. The different role of the collected species is discussed. The vector competence of An. maculipennis and Cq. richiardii needs further investigation, because the importance of these species poorly represented, and the role of species such as Aedes albopictus (Skuse), characterized by a dominant diurnal activity pattern, has to be evaluated.

Aedes albopictus and Culex pipiens implicated as natural vectors of Dirofilaria repens in central Italy

Abstract To identify the natural vectors of Dirofilaria repens Railliet et Henry, entomological samplings were carried out in four sites within the Lazio region, foci of canine subcutaneous dirofilariasis. Collections were made in 2002–2003 by means of dog-baited and miniature Centers for Disease Control and Prevention traps as well as on humans. Microscopy identified 1,576 attracted mosquito females as belonging to six species, but molecular diagnostics detected filarial DNA only in Culex pipiens L. and Aedes albopictus (Skuse, 1894). Dirofilaria immitis Leidy DNA, D. repens DNA, or both were found in the head and thorax of both mosquitoes. The simultaneous presence of vectors showing diurnal and nocturnal activity patterns is of concern for animal and human health. The finding of D. immitis DNA in mosquitoes in areas where only D. repens was been recovered in dogs also demonstrates that this filarial parasite circulates among carnivores (wild or domesticated pets).

Tick reservoirs for piroplasms in central and northern Italy.

Ticks, collected in central and northern Italy from pets, livestock, wild animals and the environment (n=2107), were identified by microscopy and processed by molecular diagnostics to determine the species that act as a reservoir for piroplasms. A total of 11 ixodid tick species were identified, with five of them proving to be piroplasm positive. Molecular diagnostics identified Theileria equi and eight Babesia species in 52 adult specimens, mostly (n=50) removed from piroplasm-free vertebrate hosts. Ixodes ricinus hosted the highest number of species, although the highest infection rate was recorded in Hyalomma marginatum (9.1%), followed by I. ricinus (5.1%), Dermacentor marginatus (5%), Rhipicephalus turanicus (3.1%) and R. sanguineus (1.2%). Novel tick/pathogen associations were detected, suggesting that certain tick species (such as Hy. marginatum, R. sanguineus and I. ricinus) are vector of more piroplasm species than previously thought. Trans-stadial maintenance of the piroplasms was observed in each positive tick species; vertical transmission of B. canis canis was demonstrated in R. sanguineus. Finally, the detection of Babesia sp., B. microti-like species and B. rodhaini, phylogenetically related to zoonotic species, suggests that the human population could be at risk of infection in the studied area.

The first report of hepatozoon canis identified in vulpes vulpes and Ticks from Italy

This is the first report on the presence of Hepatozoon canis in Vulpes vulpes in Italy. During the years 2005 and 2006, a total of 119 foxes were collected and their spleen tissues were screened by microscopy, polymerase chain reaction, and sequencing. In the same area, 290 ticks were picked off from dogs or collected from the environment. Microscopy detected inclusion bodies regarded as belonging to the genus Hepatozoon in four samples, whereas molecular diagnostics evidenced 16 foxes (13.4%) and 6 ticks (2.1%) positive to H. canis. The H. canis isolates we found in foxes, compared with the strains we previously detected in dogs from the same area and with the strains found in foxes from other European countries, show a certain genetic heterogeneity. In fact, seven isolates cluster with the Italian dog strain and nine isolates cluster with the fox strain found in Spain and Slovakia; moreover, the dogs strain is closely related to one ticks isolate, and the strain found in three Rhipicephalus sanguineus and in one Ixodes ricinus collected from the environment cluster with the aforementioned Spanish and Slovak fox strains. Our findings confirm the importance of R. sanguineus as final host and suggest that I. ricinus might also be implicated in parasite transmission, explaining in that way the occurrence of hepatozoonosis in areas considered R. sanguineus-free. The peridomestic habits of V. vulpes and the increasing global temperature are expected to amplify the impact of this vector-borne disease and to enforce the transmission of Hepatozoon to domestic animals.

Vulpes vulpes: A Possible Wild Reservoir for Zoonotic Filariae

Foxes (Vulpes vulpes, n = 132) killed during the hunting seasons 2005-2006 in Central Italy (Tuscany region) were examined in order to investigate the possible importance of this animal as a wild reservoir for zoonotic filariae. In each specimen adult worms of Dirofilaria immitis and hematic microfilariae were searched for. Species identification was performed by morphology, morphometry, the Barka staining technique applied to pulmonary and splenic blood smears, and, finally, by molecular diagnostics -- polymerase chain reaction (PCR) and sequencing. Twenty-three subjects (17.4%) proved to be positive for filarial parasites. Infection by Acanthocheilonema was more widespread than by Dirofilaria. Briefly, 8 foxes harbored mature adults of D. immitis; two of them (25%) also had microfilariae that in one case were mixed with the microfilariae of D. repens. Twelve subjects had microfilariae of Acanthocheilonema reconditum, and 3 harbored microfilariae of A. dracunculoides. Molecular diagnostics confirmed all results. Our findings, drawn by the examination of a few microliters of blood obtained from foxes approximately <2 years of age, support the hypothesis that this animal may be an abundant source of infection for ticks that transmit Acanthocheilonema parasites and for mosquitoes that act as vectors for dirofilarial nematodes. Therefore foxes, contributing to the parasite circulation in areas where dogs usually undergo prophylactic treatment, have to be considered an important wild reservoir for filarial parasites that can be transmitted to companion animals and people.

Muscular cystic hydatidosis: case report

BackgroundHydatidosis is a zoonosis caused by Echinococcus granulosus, and ingesting eggs released through the faeces from infected dogs infects humans. The location of the hydatid cysts is mostly hepatic and/or pulmonary, whereas musculoskeletal hydatidosis is very rare.Case presentationWe report an unusual case of primary muscular hydatidosis in proximity of the big adductor in a young Sicilian man. The patient, 34 years old, was admitted to the Department of Infectious and Tropical Diseases for ultrasonographic detection, with successive confirmation by magnetic resonance imaging, of an ovular mass (13 × 8 cm) in the big adductor of the left thigh, cyst-like, and containing several small cystic formations. Serological tests for hydatidosis gave negative results. A second drawing of blood was done 10 days after the first one and showed an increase in the antibody titer for hydatidosis. The patient was submitted to surgical excision of the lesion with perioperatory prophylaxis with albendazole. The histopathological examination of the bioptic material was not diriment in the diagnosis, therefore further tests were performed: additional serological tests for hydatidosis for the evaluation of IgE and IgG serotype (Western Blot and REAST), and molecular analysis of the excised material. These more specific serological tests gave positive results for hydatidosis, and the sequencing of the polymerase chain reaction products from the cyst evidenced E. granulosus DNA, genotype G1. Any post-surgery complications was observed during 6 following months.ConclusionCystic hydatidosis should always be considered in the differential diagnosis of any cystic mass, regardless of its location, also in epidemiological contests less suggestive of the disease. The diagnosis should be achieved by taking into consideration the clinical aspects, the epidemiology of the disease, the imaging and immunological tests but, as demonstrated in this case, without neglecting the numerous possibilities offered by new serological devices and modern day molecular biology techniques.

Canine and human Dirofilaria infections in the Balkan Peninsula

Dirofilaria immitis and Dirofilaria repens infections are mosquito-borne diseases, mainly of dogs. Both parasites are zoonotic, and they sometimes cause serious infections in humans. The aim of this short review was to examine the situation in the Balkan Peninsula, from where it is not always easy to obtain suitable data, often reported in journals and other publications difficult to be retrieved and with poor or no visibility. The review included data from international and regional literature, doctoral theses, and conference proceedings.