Background: Considering the increasing importance of small animals travel medicine and the spread of filariae with zoonotic potential to non-endemic European areas, routine filarial diagnosis in dogs is becoming important. Dirofilaria immitis, D. repens, Acanthocheilonema dracunculoides and A. reconditum are the most common canine filarial nematodes presenting blood circulating microfilariae (mf) which can be differentiated to species level by the acid phosphatase activity patterns or by PCR. Available data on the size of the mf vary considerably in the literature. The aim of this study was to validate morphometric criteria for filarial identification in blood samples of dogs after concentration of mf with the modified Knott’s technique. Methods: Morphometric analysis of 10 mf from samples identified to species level by acid phosphatase activity and partially confirmed by PCR were performed with specimens from 377 dogs. Results: The mean length and width of D. immitis mf from 60 dogs were 301.77±6.29 μm and 6.30±0.26 μm, of D. repens mf from 171 dogs 369.44±10.76 μm 8.87±0.58 μm, of A. dracunculoides mf from 133 dogs 259.43±6.69 μm and 5.09±0.47 μm and of A. reconditum mf from 13 dogs 264.83±5.47 μm and 4.63±0.52 μm. For a subset of 30 samples, morphometric analysis was repeated with identical results in two laboratories. Furthermore, the size of mf concentrated and fixed by the Knott’s technique was shown to be stable over 105 days. Conclusions: The Knott’s test enables to clearly distinguish between D. immitis, D. repens and Acanthocheilonema spp. However, due to the overlapping size ranges of A. dracunculoides and A. reconditum, biochemical or molecular methods are required to distinguish these two species.

A parasitologic study on 129 red foxes (Vulpes vulpes) from Tuscany (central Italy) was carried out in 2004-2006. Five intestinal species were found at necropsy: Dipylidium caninum (prevalence 57.3%), Mesocestoides lineatus (45.4%), Uncinaria stenocephala (39.1%), Toxocara canis (9.1%), and Toxascaris leonina (5.4%). Other parasites not associated with the intestine included Crenosoma vulpis (14.7%), Capillaria aerophila (7.0%), Angiostrongylus vasorum (7.0%), and filarial parasites (17.8%). Coprologic tests were less sensitive and less specific in identifying parasites than direct examinations at necropsy. Trichinella larvae were not found in muscles submitted to artificial digestion. By immunologic assay, antigens of Echinococcus spp. were detected in fecal samples of 20 foxes, but results could not be confirmed by fecal examination or molecular tests.

Extraintestinal nematodes of the red fox (Vulpes vulpes) are a wide group of parasites that infect wild and domestic carnivores and occasionally humans. Nematodes in the cardiopulmonary system, stomach, urinary apparatus and muscle tissue of 165 red foxes (Vulpes vulpes) from north-west Italy (Liguria and Piedmont) were investigated between 2009 and 2012. Of the cardiopulmonary nematodes, a high prevalence ofAngiostrongylus vasorumandEucoleus aerophilus(syn.Capillaria aerophila) was found, 78.2% and 41.8% respectively;Crenosoma vulpis(15.8%) andFilaroidesspp. (4.8%) were also found.Spirocerca lupi(23.5%),Aonchotheca putorii(syn.Capillaria putorii) (8.6%) andPhysalopteraspp. (2.5%) were detected in the stomach andPearsonema plica(syn.Capillaria plica) (56.8%) in the bladder.Eucoleus boehmi(syn.Capillaria boehmi)was also detected in the nasal cavities of one of the two foxes examined. A coprological examination revealed eggs ofE. aerophilus,A. putorii,S. lupi,Physalopteraspp. and eggs of intestinal parasites. Filarial worms were absent in all the 165 animals examined, nor was there evidence ofTrichinellaspp. in any of the foxes. The foxes were found to host a high prevalence of many species of extraintestinal nematodes. The prevalence ofA. vasorumin foxes found in the present study is among the highest in Europe. In addition, to the best of our knowledge,E. boehmiandFilaroidesspp. have never been reported before in this host in Italy.

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.

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 reg