Felid Lungworms and Heartworms in Italy: More Questions than Answers?

Nematodes infecting the cardiorespiratory system of cats have recently stimulated high scientific interest. Over the past few years, different aspects of these parasites have been clarified and various issues elucidated. This increased knowledge has improved awareness on this topic but, at the same time, some dilemmas have not been solved and new questions have been raised. In this review, we underline and discuss current knowledge of, and new doubts relating to, feline lungworms and heartworms, with the aim of stimulating new studies to fill gaps of basic (i.e., epidemiology and biology) and applied (i.e., clinical aspects) knowledge of the old and new parasites affecting the cardiorespiratory system of cats.

Irreversible pulmonary hypertension associated with Troglostrongylus brevior infection in a kitten

A four month-old kitten was referred at the Veterinary Teaching Hospital of Teramo, Italy. Physical examination, echocardiography, thoracic radiography, copromicroscopy and biomolecular assays led to a diagnosis of severe parasitic bronchopneumonia by Troglostrongylus brevior complicated by pulmonary hypertension. A single administration of a spot on solution containing imidacloprid 10%/moxidectin 1% was effective in stopping larval shedding but clinical, radiographic and echocardiographic signs of bronchopneumonia and pulmonary hypertension still persisted after further follow-ups.While cases of pulmonary hypertension are known in infections by Aelurostrongylus abstrusus, this is the first report of irreversible pulmonary hypertension in a kitten with troglostrongylosis.

Respiratory nematodes in cat populations of Italy

The occurrence of common respiratory parasites of domestic cats (the metastrongyloid "cat lungworm" Aelurostrongylus abstrusus and the trichuroid Capillaria aerophila) and of neglected respiratory nematodes of felids (Troglostrongylus brevior, Angiostrongylus chabaudi and Oslerus rostratus) was here evaluated in two and three geographical sites of Northern and Central Italy, respectively. In 2014-2015, individual fecal samples of 868 domestic cats were examined microscopically and genetically, and epidemiological data related to parasitic infections were evaluated as possible risk factors by binary logistic regression models. The most common parasite was A. abstrusus in both mono- and poli-specific infections, followed by T. brevior and C. aerophila, while cats scored negative for other parasites. Cats positive for A. abstrusus (1.9-17 % infection rate) and C. aerophila (0.9-4.8 % infection rate) were found in all examined sites, while cats scored positive for T. brevior (1-14.3 % infection rate) in four sites. Also, T. brevior was here found for the first time in a domestic cat from a mountainous area of Northern Italy. The occurrence of lungworms was statistically related to the presence of respiratory signs and more significant in cats with mixed infection by other lungworms and/or intestinal parasites. Cats living in site C of Central Italy resulted statistically more at risk of infection for lungworms than cats living in the other study sites, while animals ageing less than 1 year were at more risk for troglostrongylosis. Finally, the presence of lungworms was more significant in cats with mixed infection by other lungworms and/or intestinal parasites. These results are discussed under epidemiological and clinical points of views.

Elusive Angiostrongylus vasorum infections

Background

The parasitic nematode Angiostrongylus vasorum causes severe clinical signs in dogs. The disease is often challenging because infected animals are often presented with clinical signs overlapping those of other diseases.

Methods

The present article describes six angiostrongylosis cases (Cases 1-6) that represent key examples of how canine angiostrongylosis may be extremely confounding. The six animals presented clinical signs compatible with canine angiostrongylosis but they were subjected to clinical examinations for other diseases (e.g. dirofilariosis or immune-mediated disorders) before achieving a correct diagnosis.

Results

In Case 1 clinical, radiographic and ultrasound examinations' results resembled a lung neoplasia. Case 2 was a dog with a mixed infection caused by A. vasorum and Dirofilaria immitis. Case 3 was a critically ill dog presented in emergency for an acute onset of dyspnoea caused by lungworm infection. The dog died a few hours after presentation despite support and etiologic therapy. Case 4 was a dog presented for chronic hemorrhages and ecchymoses caused by thrombocytopenia of unknown origin, thought to have an inherited, immune-mediated or infective cause. Case 5 was referred for neurological signs due to a suspected discospondylitis. Case 6 was erroneously diagnosed infected only with D. immitis although the dog was infected only with A. vasorum. A timely administration of an anthelmintic (mostly moxidectin) showed to be effective in treating the infection in those dogs (i.e. Cases 1,2, 4 and 5) that did not suffer with severe lung haemorrhages yet.

Conclusions

Dogs 1-5 were referred in two regions of Italy that are considered non-endemic for A. vasorum. These findings indicate that veterinarians should include angiostrongylosis in the differential diagnosis of cardio-respiratory distress also in non-endemic regions and should perform appropriate diagnostics in the presence of compatible signs even if the clinical picture is atypical.

Anthelmintic resistance to ivermectin and moxidectin in gastrointestinal nematodes of cattle in Europe

Anthelmintic resistance has been increasingly reported in cattle worldwide over the last decade, although reports from Europe are more limited. The objective of the present study was to evaluate the efficacy of injectable formulations of ivermectin and moxidectin at 0.2 mg per kg bodyweight against naturally acquired gastro-intestinal nematodes in cattle. A total of 753 animals on 40 farms were enrolled in Germany (12 farms), the UK (10 farms), Italy (10 farms), and France (8 farms). Animals were selected based on pre-treatment faecal egg counts and were allocated to one of the two treatment groups. Each treatment group consisted of between 7 and 10 animals. A post-treatment faecal egg count was performed 14 days (±2 days) after treatment. The observed percentage reduction was calculated for each treatment group based on the arithmetic mean faecal egg count before and after treatment. The resistance status was evaluated based on the reduction in arithmetic mean faecal egg count and both the lower and upper 95% confidence limits. A decreased efficacy was observed in half or more of the farms in Germany, France and the UK. For moxidectin, resistance was confirmed on 3 farms in France, and on 1 farm in Germany and the UK. For ivermectin, resistance was confirmed on 3 farms in the UK, and on 1 farm in Germany and France. The remaining farms with decreased efficacy were classified as having an inconclusive resistance status based on the available data. After treatment Cooperia spp. larvae were most frequently identified, though Ostertagia ostertagi was also found, in particular within the UK and Germany. The present study reports lower than expected efficacy for ivermectin and moxidectin (based on the reduction in egg excretion after treatment) on European cattle farms, with confirmed anthelmintic resistance on 12.5% of the farms.

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Multi-centre study in four major cattle markets in Europe.

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Decreased efficacy in more than half of the farms in three out of four countries.

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12.5% of farms with confirmed anthelmintic resistance to ivermectin and moxidectin.

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Mainly Cooperia larvae found in post-treatment copro-cultures.

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Also Ostertagia ostertagi larvae found in post-treatment copro-cultures.

PCR-based assay for the mitochondrial cox1 specific amplification of Eucoleus böhmi

Eucoleus böhmi (syn. Capillaria boehmi) is a trichuroid nematode affecting the epithelium of the nasal turbinates, frontal and paranasal sinuses of wild and domestic canids. Knowledge of the geographic distribution of nasal eucoleosis is fragmentary, despite the infection has been described from Europe and North America. Moreover, gaps exist in information available on the importance of the disease in canine clinical practice. The lack of knowledge on E. böhmi is likely due to limitations inherent to diagnostic methodologies. The aim of the present work was to assess a PCR-based assay instrumental to the amplification of a species-specific region of the mitochondrial DNA (mtDNA) gene encoding for the subunit 1 (cox1) gene of E. böhmi. Adult worms of E. böhmi from red foxes and dogs from Norway, Serbia and Italy and individual fecal samples from naturally infected dogs from Italy were included in the study. Stool samples from dogs negative for E. böhmi, but positive for other common parasites in both single and mixed infections, and adult stages of common dog parasites, were used to assess the specificity of this genetic assay. Using the panel of faecal samples, the assay showed a sensitivity of 85.14% and a specificity of 100%.

Thelazia callipaeda (Spirurida: Thelaziidae): first report in Greece and a case of canine infection

The eyeworm Thelazia callipaeda has been reported in different European countries, i.e. Italy, France, Germany, Switzerland, Spain, Portugal, Bosnia and Herzegovina, Croatia and Romania. The present article describes the first autochthonous case of ocular thelaziosis in a dog from Greece, thus revealing a new spot of infection in Europe. The dog in this case report, most likely infected at the northern borders of Greece, was referred to a private veterinary practice with conjunctivitis, oedema, keratitis, epiphora and mucoid discharge in both eyes. Seventy-seven nematodes were removed from both eyes, and the dog was treated with two subcutaneous injections of ivermectin 14 days apart, in combination with a topical antimicrobial medication. The parasites were morphologically and molecularly identified as T. callipaeda. Although in Greece there is no information about the presence and distribution of the fruit fly Phortica variegata, i.e. the intermediate host of T. callipaeda, the location where the dog was infected is environmentally suitable for its development. The present report of this zoonotic parasitosis indicates that in Greece, along with endemic areas in Spain and Italy, T. callipaeda is currently reaching its southernmost distribution limit in Europe.

Treatment of Troglostrongylus brevior (Metastrongyloidea, Crenosomatidae) in mixed lungworm infections using spot-on emodepside

Feline lungworms have long been known as pathogens of cats. However, an increased incidence of clinical cases in some areas has been the focus of a number of recent epidemiological and clinical studies. While Aelurostrongylus abstrusus causes respiratory signs in cats all over the world, Troglostrongylus brevior has recently been found in domestic cats from Spain and Italy (where it often causes severe clinical signs). Capillaria aerophila, a parasite that infects many wild carnivores, may cause respiratory distress in cats. A variety of treatment options are known for A abstrusus, while almost no information is available on the treatment of troglostrongylosis and capillariosis. This series describes two mixed infections in clinically affected kittens with T brevior, one with concurrent A abstrusus and the other with C aerophila. In both cases, the nematodes were identified and confirmed by copromicroscopic examination and specific DNA-based assays. Kittens showed respiratory signs that resolved after one or two administrations of a spot-on solution containing emodepside. Larval (T brevior and A abstrusus) and egg (C aerophila) shedding was also eliminated 2-4 weeks after treatment. New clinical insights into these parasitoses are discussed.

Canine angiostrongylosis: recent advances in diagnosis, prevention, and treatment

Angiostrongylus vasorum is a parasitic nematode affecting the heart and pulmonary arteries of wild (eg, foxes) and domestic canids. The parasite has an indirect life cycle in which slugs and snails act as intermediate hosts. In the last few years the parasite has spread outside the traditional endemic foci, and there is a rise of documented cases of canine angiostrongylosis across Europe. Angiostrongylus vasorum causes cardiopulmonary disorders and coagulopathies, along with different nonspecific clinical signs. Fatal infections are frequently reported. Given the severity of the infection and the recent geographic spreading of the parasite, this article reviews and discusses the current knowledge of A. vasorum, with a special focus on recent insights on diagnosis, prevention, and treatment of dog angiostrongylosis.

A retrospective and geographical epidemiological survey of traumatic myiasis in southern Italy

A survey on the prevalence and geographical distribution of traumatic myiasis in sheep, and the risk factors for the disease, was carried out in a region of southern Italy. A total of 138 sheep flocks were selected and visited to acquire data on the presence or absence of traumatic myiasis using both a questionnaire for retrospective analysis and animal inspection. Prevalences registered at the farm and animal levels, respectively, were 8.7% and 6.3% in 2010, and 5.8% and 5.0% in 2011. Records of the occurrence of the parasitic disease in this region are recent: a statistically significant (P < 0.01) progressive increase in the number of farms affected (from 0.7% to 8.7%) has been registered since 2007. Wohlfahrtiosis was found in 11 of 95 (11.6%) geographical units sampled and three significant (P < 0.05) clusters of spatial farm aggregation were identified in the southern part of the study area. A total of 158 presently uninfested farms were considered to be at high risk for transmission as a result of their proximity to infested farms. The spreading of Wohlfahrtia magnifica (Diptera: Sarcophagidae) in southern regions of Italy represents a warning that the risk for infestation may become more significant in other Italian regions, as well as other European countries.

Cardio-Pulmonary Parasitic Nematodes Affecting Cats in Europe: Unraveling the Past, Depicting the Present, and Predicting the Future

Various cardio-pulmonary parasitic nematodes infecting cats have recently been fascinating and stimulating the attention of the Academia, pharmaceutical companies, and veterinary practitioners. This is the case of the metastrongyloids: Aelurostrongylus abstrusus and Troglostrongylus brevior, the trichuroid: Capillaria aerophila (syn. Eucoleus aerophilus), and the filarioid: Dirofilaria immitis. Apparently, these parasites have been emerging in several European countries, thus, gaining an important role in feline parasitology and clinical practice. Under a practical standpoint, a sound knowledge of the biological, epidemiological, and clinical impact of cardio-respiratory parasitoses affecting cats, in addition to a potential risk of introduction, establishment, and spreading of “new” parasites in Europe is mandatory in order to understand the present and future impact for feline medicine and to address new strategies of control and treatment. The purpose of the present article is to review the current knowledge of heartworm and lungworm infections in cats, discussing and comparing past and present issues, and predicting possible future scenarios.

First report of Troglostrongylus brevior in a kitten in Greece

The first case of a natural infestation with Troglostrongylus brevior in a kitten in Greece is described here. A ∼40-day-old stray cat was referred to a private veterinary clinic with signs of respiratory distress. First stage larvae of a metastrongyloid nematode were observed in the wet mount faecal preparation. Despite an anthelmintic treatment, the respiratory signs worsened and the kitten died 2 days later. The larvae in the faeces were identified morphologically and genetically as T. brevior. The present evidence suggests a vertical or direct infestation of the kitten and a severe pathogenic role of T. brevior in young cats. This report expands the recent published cases of troglostrongylosis in domestic cats to a wider geographical distribution and opens new questions on the apparent spreading of T. brevior from wild to domestic hosts.

Field clinical study evaluating the efficacy and safety of an oral formulation containing milbemycin oxime/praziquantel (Milbemax®, Novartis Animal Health) in the chemoprevention of the zoonotic canine infection by Dirofilaria repens

BACKGROUND

Dirofilaria repens is the causative agent of subcutaneous dirofilariosis of dogs, other animals and humans. This nematode is transmitted by mosquitoes of Aedes, Anopheles and Culex genera. In dogs, the parasite may cause subclinical infection or cutaneous signs. Recently, D. repens has emerged and spread in different geographical areas, with an increase of cases in dogs and humans. Chemoprevention in dogs in endemic areas is the most reliable approach for controlling this infection. This paper describes a randomized, blocked and multicentric clinical field study investigating the efficacy of an oral, chewable formulation containing milbemycin oxime/praziquantel (Milbemax®, Novartis Animal Health) in the chemoprevention of subcutaneous dirofilariosis in dogs.

METHODS

This study was conducted in endemic areas of Italy. A total of 249 dogs, at two sites, negative for D. repens, were allocated into two groups (i.e. Treated -T1 vs Untreated-T2) with a ratio of 1:1, and subjected to clinical visits and blood sampling once monthly until the end of the study. All blood samples were microscopically and genetically examined. Animals belonging to T1 group received a minimum target dose of 0.5 mg/kg bodyweight of milbemycin oxime and 5 mg/kg of praziquantel in commercial tablets (Milbemax®) according body weight once every 4 weeks. Animals of group T2 were not treated with Milbemax® but received, when necessary, specific parasiticide treatments. The study duration was 336 ± 2 days for each dog.

RESULTS

A total of 219 dogs completed the study (i.e. 111 in T1 and 108 in T2), while 30 dogs (i.e. 13 in T1, 17 in T2) were withdrawn for a variety of reasons unrelated to administration of Milbemax®. The percentages of animals not showing microfilariae of D. repens were 100% (111 animals) in T1 and 94.7% (108 animals out of 114) in group T2. Milbemax® was shown to be safe in treated dogs.

CONCLUSIONS

The results of this study confirm that the monthly use of Milbemax® in dogs is effective and safe for the prevention of subcutaneous dirofilariosis in endemic areas.

Canine giardiosis in Sardinia Island, Italy: prevalence, molecular characterization, and risk factors

Introduction: The flagellate protozoan Giardia duodenalis causes infection in humans and in various animals. Eight distinct assemblages (A-H) have been identified within G. duodenalis; assemblages A and B are those specific to humans and animals, and assemblages C to H are restricted to animal hosts. Methodology: The present study estimated the prevalence of G. duodenalis assemblages in dogs living in the Sardinia region and evaluated the related risk factors. Individual fecal samples were collected from 655 dogs between January 2007 and December 2010, and a form was filled out for each animal to analyze historic data that were available at the time of sampling. Fecal samples were subjected to microscopic and genetic investigations. Results: Cysts of G. duodenalis were found in 172 (26.3%) samples, with significant values in puppies between three and nine months of age, and in kennelled and hunting dogs. The molecular characterization showed the presence of assemblages D (49%), C (36.1%), and subtype A2 (4.2%). Conclusion: The present survey contributes to the knowledge of the occurrence of canine giardiosis in Italy in a region with a high number of dogs and numerous animal movements, which is especially relevant for touristic reasons.

Environmental contamination by canine geohelminths

Intestinal nematodes affecting dogs, i.e. roundworms, hookworms and whipworms, have a relevant health-risk impact for animals and, for most of them, for human beings. Both dogs and humans are typically infected by ingesting infective stages, (i.e. larvated eggs or larvae) present in the environment. The existence of a high rate of soil and grass contamination with infective parasitic elements has been demonstrated worldwide in leisure, recreational, public and urban areas, i.e. parks, green areas, bicycle paths, city squares, playgrounds, sandpits, beaches. This review discusses the epidemiological and sanitary importance of faecal pollution with canine intestinal parasites in urban environments and the integrated approaches useful to minimize the risk of infection in different settings.

Anthelmintic resistance and multidrug resistance in sheep gastro-intestinal nematodes in France, Greece and Italy

Anthelmintic resistance (AR) in ovine gastro-intestinal nematodes has been reported to affect the health and productivity of sheep globally. The objective of the present study was to evaluate the efficacy of commonly used oral drenches in sheep in France, Greece and Italy. In each country, 10 farms were selected. On each farm, 50 animals were blocked based on the pre-treatment faecal egg count (FEC). Within each block, animals were randomly allocated to one of 5 treatment groups. In addition to an untreated control group, there were 4 groups treated per oral route: moxidectin (MOX) and ivermectin (IVM), both at 0.2mg/kg bodyweight, levamisole (LEV; at 7.5mg/kg bodyweight) and a benzimidazole (BZ; at 3.75-5mg/kg bodyweight). In France, animals were not treated with LEV, but with netobimin (NET; at 7.5mg/kg bodyweight). The FEC was monitored using a modified McMaster technique. Two weeks after treatment, individual faecal samples were taken from all animals and efficacy was calculated as the difference between arithmetic mean FEC of the control group versus each respective treatment group. The results of the present study indicate the high efficacy of treatment with oral formulations of MOX (99-100%) and IVM (98-100%) on all farms, except on 1 farm in Greece. On this farm, multi drug resistance (MDR) was identified involving 4 anthelmintics (efficacy MOX: 91%; IVM: 0%; BZ: 58% and LEV: 87%). In Greece and Italy, AR against LEV and BZ was observed on some farms, with MDR involving both anthelmintics on 3 farms in Greece and on 2 farms in Italy. In France, AR against BZ and NET was observed on all 10 farms included. In all countries, Teladorsagia sp. was the most common nematode larva identified after treatment, followed by Haemonchus sp. and Trichostrongylus sp., with differences among farms and treatments. The current study confirms the high efficacy of oral treatments with MOX and IVM, even on farms with worm populations resistant to BZ, LEV or NET. This study also reports MDR against 4 anthelmintics on one farm in Greece.

Response to Giannelli et al.--comments on potential efficacy of monthly administrations of spot-on moxidectin 2.5%/imidacloprid 10% in the simultaneous prevention of major canine filarioses

Some comments have been done on an article describing a pilot trial evaluating the potential use of moxidectin contained in a spot-on formulation in the prevention of canine filarioses in a confined area where the three major canine filariae live in sympatry. We herein present our response to these comments.

A pilot trial evaluating the efficacy of a 10% imidacloprid/2.5% moxidectin spot-on formulation in the treatment of natural nasal capillariosis in dogs

The efficacy and safety of a spot-on formulation containing 10% imidacloprid and 2.5% moxidectin (Advocate(®), Bayer Animal Health GmbH, Leverkusen, Germany) were evaluated in a pilot trial for the treatment of canine nasal capillariosis caused by Capillaria boehmi (syn. Eucoleus boehmi). Sixteen dogs copromicroscopically positive for C. boehmi eggs were confirmed, either by rhinoscopy or species-specific PCR-coupled sequencing assays, as being affected by nasal capillariosis. The animals were randomly allocated to two different study groups, i.e. one (Group T) treated with Advocate(®) and one (Group C) left untreated, in a ratio of 1:1. The animals underwent clinical examination and quantitative copromicroscopy for C. boehmi eggs on Days -6 and -2 (baseline) and Day 28 ± 2 (post-baseline). Animals in Group T received Advocate(®) on Day 0. On Day 28 ± 2 the efficacy of the treatment (Group T) or the persistence of the infection (Group C) was confirmed by rhinoscopy or, alternatively, by molecular procedures. Seven of the eight dogs in Group T were negative on Day 28 ± 2 (reduction of baseline faecal egg counts by 99.14%), while for one dog a second treatment on Day 28 ± 2 was necessary to clear the infection, as demonstrated on Day 56 ± 2 (reduction of baseline faecal egg counts by 100% in Group T). Seven animals in Group C received a rescue dose of Advocate(®) on Day 28 ± 2 and scored microscopically and molecularly negative for the parasite on Day 56 ± 2, thus increasing the reduction of post-baseline egg counts to 99.57% after a single administration. These promising results show that Advocate(®) spot-on is an effective formulation for the treatment of canine nasal capillariosis under field conditions.

Angiostrongylus vasorum in wolves in Italy

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Nematodes found in dead wolves in Rome province, Italy, were confirmed to be Angiostrongylus vasorum.

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Molecular evidence further showed homology with lungworm larvae in sympatric dogs.

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It is not known whether wolves represent ancentral hosts or are subject to more recent spill-over from dogs and foxes.

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The parasite is pathogenic, emerging, and should be borne in mind in wolf conservation programmes in endemic areas.

In the past decade, the parasitic nematode Angiostrongylus vasorum has attracted attention for its emergence in previously free areas and for the rise in clinical cases in domestic dogs. Italy is regarded as one of the countries where this potentially life-threatening parasite is spreading, especially due to bridging infections between wildlife and domestic dogs. The present article describes the presence of A. vasorum in wolves from Italy. Nematodes were observed in histological sections of three wolves found dead in Rome province, central Italy. Morphological and molecular identification of the nematodes, by polymerase chain reaction of rDNA ITS-2 and sequencing, confirmed the nematodes to be A. vasorum, with 99% genetic homology with A. vasorum from sympatric dogs. This is the second report of this species in wolves and the first in this host in Italy, and coincides with increasing records of A. vasorum in dogs and foxes in Italy. Implications for the epidemiology of this emerging parasite and for wildlife health are concisely discussed.

Microfilarial periodicity of Dirofilaria repens in naturally infested dogs

In the past years, canine and human cases of infestation by Dirofilaria repens (Spirurida, Onchocercidae) have been increasingly reported in several European countries. Subcutaneous dirofilariosis by D. repens may either be asymptomatic in dogs or may be characterized by subcutaneous nodules and other symptoms. Information on the periodicity of D. repens microfilariae in naturally infested animals is scant, and this might impair the accurate diagnosis of subcutaneous dirofilariosis and appropriate control plans. In the present study, eight dogs infested with D. repens were sampled twice daily at 12-h intervals for ten consecutive days, and the dog with the highest mean value of microfilariaemia was further sampled every 4 h for four consecutive days. The blood was microscopically and molecularly examined for microfilariae, and, additionally, negative samples were also subjected to a real-time PCR to evaluate the level of circulating DNA. The results demonstrated significant variations in circadian rhythms of D. repens larvae, with higher values of microfilariae per milliliter in the evening samples. A significant variation was also found at the individual level for the dogs with the highest values of microfilariaemia. All samples which were negative at the light microscopy and positive at the real-time PCR displayed levels of circulating parasite DNA <1 microfilaria per milliliter. Biological and clinical implications have been here discussed.