New insights onto cardiopulmonary nematodes of dogs in Sardinia, Italy

Survey of Gastrointestinal Parasites and Lungworms in Cats and Dogs from Terceira and São Miguel Islands, Azores

Parasitic diseases can affect animal health and welfare, and they may also constitute a danger to public health, particularly in island ecosystems. Fecal samples were collected from 205 dogs and 115 cats on the islands of São Miguel and Terceira, Azores archipelago (Portugal), using the Willis flotation technique and modified Baermann method, for further analysis. The overall prevalence of gastrointestinal parasitism in dogs was 53%, with the following results: Ancylostomatidae (hookworms) (42.44%), Trichuris vulpis (17.56%), Toxocara canis (12.68%) and Cystoisospora spp. (4.39%). In cats, the overall prevalence was also 53%, with the following results: Toxocara cati (31.3%), Ancylostomatidae (30.43%), Cystoisospora spp. (14.78%) and Trichuris sp. (0.87%). The prevalence of lungworms was 0.49% in canines and 20.87% in felines, with Angiostrongylus vasorum and Aelurostrongylus abstrusus species being detected in dogs and cats, respectively. The present survey detected a high prevalence of gastrointestinal infection, in both dogs and cats, probably because the samples came mainly from kennels and catteries and due to the peculiar climatic conditions in this insular territory, with mild temperature and high relative humidity. A considerable prevalence of aelurostrongylosis was also detected (20.87%), so it should be included in the list of differential diagnoses of diseases concerning the respiratory tract in cats of the archipelago.

Cardio-pulmonary nematodes of the red fox (Vulpes vulpes) of Sardinia, Italy

Cardio-pulmonary parasites, such as Angiostrongylus vasorum, Crenosoma vulpis, and Eucoleus aerophilus, pose a significant concern on account of pulmonary and cardiac problems they induce in dogs. While the red fox is known to be a key reservoir host for A. vasorum and may also play a role in transmitting C. vulpis and E. aerophilus, there has been no recent research on these parasites in foxes from Sardinia, with the most current studies dating back to 1986. A survey was conducted on red foxes in Sardinia, where a total of 51 foxes were collected, necropsied, and examined for adult worms in their hearts and lungs. The worms were identified using morphometric analysis and molecular methods. The results showed a 54.9% overall prevalence at dissection: 45.1% of the foxes were positive for E. aerophilus, 17.6% for C. vulpis, and 13.7% for A. vasorum. The molecular analyses validated the morphological characterization. In comparison to previous research, which found 13 out of 85 foxes to be positive for A. vasorum with a prevalence rate of 15.3% and 1 for E. aerophilus with a prevalence of 1.2%, this study showed an increased prevalence of E. aerophilus and C. vulpis, and a decrease in the prevalence of A. vasorum. These results indicate that the red foxes in Sardinia represent a reservoir host for cardio-pulmonary nematodes and it should be considered in the differential diagnosis of respiratory distress syndrome in dogs.

What Has Happened to Heartworm Disease in Europe in the Last 10 Years?

Heartworm disease caused by Dirofilaria immitis is a vector-borne disease that affects canids and felids, both domestic and wild, throughout the world. It is a chronic disease which causes vascular damage in pulmonary arteries, and in advanced stages, the presence of pulmonary hypertension and right-sided congestive heart failure can be evidenced. Moreover, pulmonary thromboembolism is caused by the death of the worms, which can be lethal for the infected animal. Furthermore, it is the causative agent of human pulmonary dirofilariosis, being a zoonotic disease. The aim of this review was to update the current epidemiological situation of heartworm in Europe in dogs, cats, wild animals, and vectors insects, and to analyse the factors that may have contributed to the continuous spread of the disease in the last decade (2012–2021). In Europe, the disease has extended to eastern countries, being currently endemic in countries where previously only isolated or imported cases were reported. Furthermore, its prevalence has continued to increase in southern countries, traditionally endemic. This distribution trends and changes are influenced by several factors which are discussed in this review, such as the climate changes, presence of vectors in new areas, the appearance of new competent vector species in the continent, increased movement of pets that travelled to or originated from endemic countries, the urbanisation of rural areas leading to the formation of so-called “heat islands”, or the creation of extensive areas of irrigated crops. The continuous expansion of D. immitis must be monitored, and measures adapted to the situation of each country must be carried out for adequate control.

Simultaneous Exposure to Angiostrongylus vasorum and Vector-Borne Pathogens in Dogs from Italy

Several drivers have recently fostered the expansion of Angiostrongylus vasorum throughout Europe, where Vector-Borne Pathogens (VBPs) are also spreading. However, the level of simultaneous risk of infection is still unknown in canine populations. This study evaluated the simultaneous exposure to A. vasorum and major canine VBPs in dogs of Italy. Sera of 294 dogs were subjected to two ELISAs, detecting A. vasorum circulating antigens and antibodies against the parasite, and to the following assays: (i) SNAP® 4DX (IDEXX Laboratories Inc.) detecting Dirofilaria immitis antigens, and antibodies vs. Borrelia burgdorferi, Anaplasma spp. and Ehrlichia spp. and (ii) IFAT for the detection of antibodies vs. Leishmania infantum, Babesia canis and Rickettsia conorii. Twenty-two (7.5%, CI: 4.8-11.1%) and six (2%, CI: 0.7-4.4%) dogs scored positive for circulating A. vasorum antibodies and antigens, respectively. Seventeen dogs (5.8%, CI: 3.4-9.1%) were positive for A. vasorum antibodies + at least one VBP, three (1%, CI: 0.2-3%) for A. vasorum antigen + at least one VBP, while one dog (0.3%, CI: 0.01-1.88%) was positive for A. vasorum antigen + A. vasorum antibodies + B. canis antibodies. These results show that dogs living in different regions of Italy are at risk of simultaneous infections with both A. vasorum and VBPs. Despite the same scenario being likely in other countries of Europe, the current knowledge is scant. Therefore, further studies are warranted to amplify current epizootiological information and to understand whether control programs should be improved.

Detection of Crenosoma spp., Angiostrongylus vasorum and Aelurostrongylus abstrusus in Gastropods in Eastern Austria

Canine and feline cardiorespiratory parasites are of utmost relevance in veterinary medicine. Key epizootiological information on major pet metastrongyloids, i.e., Angiostrongylus vasorum and Crenosoma vulpis infecting dogs, and Aelurostrongylus abstrusus and Troglostrongylus brevior infecting cats, is missing from Austria. This study investigated their occurrence in 1320 gastropods collected in the Austrian provinces of Styria, Burgenland, Lower Austria, and in metropolitan Vienna. Metastrongyloid larvae were microscopically detected in 25 samples, and sequence analysis confirmed the presence of metastrongyloids in nine samples, i.e., A. vasorum in one slug (Arion vulgaris) (0.07%), C. vulpis in five slugs (one Limax maximus and four A. vulgaris) (0.4%), A. abstrusus in two A. vulgaris (0.17%), and the hedgehog lungworm Crenosoma striatum was detected in one A. vulgaris. The present study confirms the enzooticity of major cardiorespiratory nematodes in Austria and that canine and feline populations are at risk of infection.

Simultaneous Detection of Parasitic Vector Borne Diseases: A Robust Cross-Sectional Survey in Hunting, Stray and Sheep Dogs in a Mediterranean Area

Canine vector-borne diseases (CVBDs) are a spectrum of diseases caused by different pathogens transmitted by blood-feeding arthropoda. The aim of this study was to investigate leishmaniosis, babesiosis, and filarial infections in dogs with three different lifestyles (hunting, stray, and sheep dogs) in Molise, the smallest region of southern Italy, where data available about these parasitic infections are very scant. A cross-sectional survey was conducted on 318 hunting, 180 stray, and 218 sheep dogs. Immunofluorescence antibody test, blood smear, molecular techniques and Knott's test were performed to detect Leishmania infantum, Babesia spp. and filarial nematodes. Association between positivity to CVBDs, age, sex, and living conditions was evaluated. An overall prevalence of 12.3% of CVBDs caused by L. infantum (10.2%), B. canis canis (0.3%) and filarial nematodes (2.1%) was detected. Three dogs showed co-infections of L. infantum and B. c. canis (0.1%) or Acanthocheilonema reconditum (0.3%). A significantly association was found only for filarial infection in hunting dogs. These parasites were reported also in dogs without clinical signs. It is very important to plan effective control programs for CVBDs to guarantee not only the health and welfare of pets, but also the public safety, because some of mentioned parasites are of zoonotic importance.

Pulmonary arterial response to Angiostrongylus vasorum in naturally infected dogs: echocardiographic findings in two cases

Background

Angiostrongylus vasorum is a nematode living in the pulmonary arteries of canids. Infected dogs develop severe pulmonary lesions which can potentially lead to pulmonary hypertension (PH). However, reports of PH in natural infected dogs are scant. One of the possible causes of the low prevalence of PH in A. vasorum-infected dogs could be the establishment of large diameter intrapulmonary arteriovenous anastomoses (IPAVAs), which attenuate pulmonary vascular resistance, thus reducing the pulmonary arterial pressure. The present report describes the pulmonary arterial pressure (PAP) response to A. vasorum natural infection in two dogs, assessed by echocardiography and by the saline contrast echocardiographic test (SCE).

Results

Both dogs showed clinical signs of respiratory disease. At presentation, case 1 did not show echocardiographic signs of PH and the SCE test was positive proving the presence of IPAVAs. However, at the follow-up visit, despite A. vasorum infection resolution, the same dog showed PH and the SCE test resulted negative, which ruled out the presence of IPAVAs. Case 2 suffered from severe pulmonary arterial hypertension and right-side congestive heart failure since the day of presentation. Saline contrast echocardiography was negative both at the time of presentation and at the follow-up visit.

Conclusions

In the two cases described above, the PH was not associated with IPAVAs. During A. vasorum infection, IPAVAs recruitment mechanism is able to contrast the rise of PAP until a certain level. It probably represents an initial escape mechanism of PH that, over time, exhausts its compensatory capacities allowing PAP to rise and to be detectable on echocardiography.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3544-2) contains supplementary material, which is available to authorized users.

Occurrence of canine and feline extra-intestinal nematodes in key endemic regions of Italy

Extra-intestinal nematodes of companion animals are of growing concern in veterinary medicine for their pathogenic potential and the current expansion throughout Europe. The present study has evaluated the occurrence of major canine and feline extra-intestinal nematodes in regions of Italy having epidemiological relevance. Associations of various recorded parameters related to the examined animals have been statistically evaluated, along with a comparative analysis with the most recent epidemiological data. Overall, 1055 dogs and 1000 cats were tested. Among extra-intestinal nematodes Angiostrongylus vasorum was the most common in dogs followed by Capillaria aerophila and Dirofilaria spp.; Aelurostrongylus abstrusus was the most recorded parasite in cats, followed by C. aerophila and Troglostrongylus brevior. The statistical analysis revealed that outdoor access is associated with A. vasorum, A. abstrusus and T. brevior infections, that were also more prevalent in animals with cardio-respiratory signs. Moreover, cats aged less than 12 months had more chances to be infected by lungworms. The data herein presented confirm the occurrence and the possible risk of expansion of different extra-intestinal parasitoses of dogs and cats in Italy, underlining the importance of a constant epidemiologic vigilance and of appropriate control methods.

Serological and molecular detection of Leishmania infantum in cats of Northern Sardinia, Italy

Leishmania infections are endemic in dogs in central and southern regions of Italy while feline leishmaniosis has only been sporadically described in these areas and few studies have been reported on serological and molecular investigation of infections in domestic cats. The purpose of this study is to assess the presence of Leishmania infantum infection in cats from Sardinia, a typical endemic area of leishmaniasis in Italy. Ninety cats attended at the Veterinary Teaching Hospital of the University of Sassari, Italy, were tested for L. infantum using the indirect immunofluorescent antibody (IFA) test and PCR. Serological (10%) and molecular (5.5%) detection in this population was low, with antibody titres ranging from 1/40 to 1/80. Only one cat was simultaneously positive by IFAT and PCR. This study shows the presence of L. infantum infection in cats living in Sardinia, with a prevalence that falls within the ranges described in other endemic areas and confirms the need of further research to better characterize the epidemiologic role of cats in the transmission of this infection.

Endoparasites detected in faecal samples from dogs and cats referred for routine clinical visit in Sardinia, Italy

This study aimed to update data on the prevalence of intestinal and lung parasitic infections in owned dogs and cats in Sardinia, Italy. Examinations on faecal samples from 619 dogs and 343 cats routinely referred to the Veterinary Teaching Hospital of the University of Sassari were performed between the years of 2011 and 2015. Individual faecal samples were analysed using the Wisconsin technique for copro-microscopic examination and the Baermann technique for the presence of lungworm larvae. Endoparasites were found in 34.9% and 43.4% of examined dogs and cats, respectively. Helminthic infections (21.2% in dogs and 32.6% in cats) occurred more frequently than protozoan infections (17.9% in dogs and 17.8% in cats). In both dogs and cats, the most common parasites were ascarids (12.1% and 15.7%), Cystoisospora spp. (10.2% and 10.8%), Giardia duodenalis (9.4% and 8.5%), and hookworms (7.9% and 5.5%). Evidence of bronchopulmonary nematode infections were found in 0.8% of examined dogs and in 15.8% of examined cats. Age was identified as a risk factor, with animals younger than 6months more frequently infected than older animals, while no significant association was observed for gender. This study demonstrated that endoparasites in owned dogs and cats of Sardinia have considerably high prevalence. Veterinary practitioners and pet owners should be more aware of these infections and should adopt more effective and standardized control practices.

Angiostrongylus vasorum infection in dogs from a cardiopulmonary dirofilariosis endemic area of Northwestern Italy: a case study and a retrospective data analysis

Background

In Italy, Angiostrongylus vasorum, an emergent parasite, is being diagnosed in dogs from areas considered free of infection so far. As clinical signs are multiple and common to other diseases, its diagnosis can be challenging. In particular, in areas where angiostrongylosis and dirofilariosis overlap, a misleading diagnosis of cardiopulmonary dirofilariosis might occur even on the basis of possible misleading outcomes from diagnostic kits.

Case presentation

Two Cavalier King Charles spaniel dogs from an Italian breeding in the Northwest were referred to a private veterinary hospital with respiratory signs. A cardiopulmonary dirofilariosis was diagnosed and the dogs treated with ivermectin, but one of them died. At necropsy, pulmonary oedema, enlargement of tracheo-bronchial lymphnodes and of cardiac right side were detected. Within the right ventricle lumen, adults of A. vasorum were found. All dogs from the same kennel were subjected to faecal examination by FLOTAC and Baermann’s techniques to detect A. vasorum first stage larvae; blood analysis by Knott’s for Dirofilaria immitis microfilariae, and antigenic tests for both A. vasorum (Angio Detect™) and D.immitis (DiroCHEK® Heartworm, Witness®Dirofilaria). The surviving dog with respiratory signs resulted positive for A. vasorum both at serum antigens and larval detection. Its Witness® test was low positive similarly to other four dogs from the same kennel, but false positive results due to cross reactions with A. vasorum were also considered. No dogs were found infected by A. vasorum.

Eventually, the investigation was deepened by browsing the pathological database of Veterinary Pathology Laboratories at Veterinary School of Milan University through 1998–2016, where 11 cases of angiostrongylosis were described. Two out of 11 dogs had a mixed infection with Crenosoma vulpis.

Conclusion

The study demonstrates the need for accurate surveys to acquire proper epidemiological data on A. vasorum infection in Northwestern Italy and for appropriate diagnostic methods. Veterinary clinicians should be warned about the occurrence of this canine parasite and the connected risk of a misleading diagnosis, particularly in areas endemic for cardiopulmonary dirofilariosis.

Dirofilaria immitis and Angiostrongylus vasorum: the contemporaneous detection in kennels

BACKGROUND

The cardiopulmonary nematodes Dirofilaria immitis and Angiostrongylus vasorum are increasingly reported in dogs and are responsible for two diseases with overlapping endemic areas, especially in Europe: dirofilariosis and angiostrongylosis. The reasons for their apparent emergence are unknown, but several factors (e.g. increased disease awareness, better diagnostic tools, climatic changes, seasonal population dynamics and movements of animals) may play a role in the recent rise in reports of infection in the various countries of Europe. The aim of this study was to investigate the seroprevalence of D. immitis (by DiroCHECK® ELISA) and the fecal presence of first stage larvae (L1) of A. vasorum (by FLOTAC) in dogs from 68 kennels of the Campania region (southern Italy). The fecal samples were collected from pooled samples using the box as epidemiological unit. To the authors's knowledge, this is the first cross-sectional survey conducted at regional-scale in Italy and in Europe on the contemporaneous detection of D. immitis antigens and A. vasorum L1 in kennels.

RESULTS

Antigens of D. immitis were detected in 24/537 (4.4%; 95% Confidence Interval = 3.0-6.7) dogs in 6 out of the 68 kennels (8.8%; 95% CI = 3.6-18.9). The 24 positive samples for D. immitis antigen were tested also with AngioDetect® and only 1 sample was seropositive for A. vasorum with a prevalence of 4.2%. A. vasorum L1 were detected in dogs from 9 out of the 68 kennels (13.2%; 95% CI = 21.8-44.9). Pooled fecal samples from 25 boxes out of the 1360 analyzed resulted positive to A. vasorum L1 (1.8%; 95% CI = 1.2-2.7).

CONCLUSIONS

The present study indicates that cardiopulmonary nematodes are present in Campania region in symptomatic dogs as well as in asymptomatic ones. Therefore, regular parasitological surveillance, appropriate treatment strategies and high quality standard of hygiene are required to guarantee the health and welfare of kennel dogs.

Canine filarial infections in Liguria, north-west Italy

This paper reports the findings of a study on the presence of various species of filarial nematodes in dogs in Liguria, north-west Italy, a region traditionally considered free from the disease. Between 2009 and 2012 blood samples were taken from 365 dogs in rural areas in Liguria. The blood samples were then submitted to Knott's test, histochemical staining, polymerase chain reaction (PCR) and the enzyme-linked immunosorbent assay (ELISA) for Dirofilaria immitis antigens. Overall, 35 of the 365 dogs were positive using Knott's test for microfilariae (prevalence 9.6%; 95% confidence interval (CI): 6.6-12.6%). Acanthocheilonema reconditum was the most prevalent species (8.0%), while Dirofilaria repens (1.4%) and Dirofilaria immitis (0.6%) were less common. One co-infection by D. repens and A. reconditum was observed. All morphological identifications were confirmed by histochemical staining and PCR. In addition, a retrospective analysis of data on D. immitis antigens in 11,363 samples of canine sera was carried out. Sera were collected and analysed for D. immitis antigens by the Istituto Zooprofilattico Sperimentale (IZS) of Piedmont, Liguria and Aosta Valley (Imperia section) between 2004 and 2013 during annual tests for leishmaniasis on autochthonous dogs throughout Liguria. Serological data from IZS showed an overall seroprevalence of 0.65% (95% CI: 0.50-0.80%) for D. immitis throughout the region. The present study updates the epidemiological map of canine filarial infections in Italy and suggests the need for surveillance and prophylaxis in Liguria.

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.

Angiostrongylus vasorum: epidemiological, clinical and histopathological insights

Background

Canine angiostrongylosis is a nematode infection in domestic dogs and wild carnivores. The present report focuses on epidemiological, clinical and histopathological findings in a case of fatal disseminated angiostrongylosis in a dog living in southern Italy and provides data on the extent of the spread of Angiostrongylus vasorum in the same area.

Case presentation

A 4-year-old female English Setter from the Campania region of southern Italy was referred with a 2-week history of cough and severe respiratory distress that did not respond to antimicrobial therapy. Based on clinical, radiological, echographical and cytological findings (including the presence of larvae), a suspect diagnosis of lungworm infection was performed. After few days the dog died due to progressive clinical aggravation. Complete postmortem examination was conducted within 24 hours from death and samples from lungs, heart, liver, kidney, spleen, stomach and small intestine were fixed in 10% buffered formalin. Grossly, several hemorrhagic foci were observed mostly in the lungs, liver, kidney. Microscopically, the lungs contained numerous, multifocal to coalescing granulomas composed of epitheliod macrophages, multinucleated giant cells and some neutrophils, frequently associated with parasite eggs and larvae. The lungs contained many firm nodules, many adult nematodes approximately 1.5 to 2 cm in length were observed in cut sections and identified as A. vasorum. A subsequent parasitological survey performed with FLOTAC on stray dogs living in the same area showed the presence of A. vasorum larvae in 17 of 1639 stray dogs examined (1.04%).

Conclusion

This survey provides new data on distribution of A. vasorum and underlines that canine angiostrongylosis should be considered as differential diagnosis in dogs.