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Cited by 19Parasitic Diseases Research and TreatmentResearch on Leishmaniasis StudiesHelminth infection and control

The Incidence of Dirofilaria immitis in Shelter Dogs and Mosquitoes in Austria

Open access
Sonnberger, Karin, Fuehrer, Hans-Peter, Sonnberger, Bernhard Werner, Leschnik, Michael·2021·Pathogens
DOI 10.3390/pathogens10050550PMC PMC8147468
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Abstract

To estimate the incidence of Dirofilaria immitis in Austrian shelter dogs and mosquitoes trapped in their proximity, 115 shelter dogs from fourteen animal shelters located in five different Austrian states were examined. Blood samples were screened for D. immitis using ELISA antigen-testing, PCR and microscopical examination for microfilariae. In total, 91% of the dogs originated from countries endemic for dirofilariosis. Eleven dogs (9.6%), all originating from Hungary, tested positive for D. immitis. None of the dogs examined showed microfilaremia. Eight dogs showed no or only mild clinical signs (e.g., infrequent coughing), and three dogs showed frequent coughing, dyspnea, exercise intolerance, blunt fur or weight loss. In total, 205 Mosquitoes of ten different species were caught at five different shelter sites in four different Austrian states, using CO2-baited mosquito traps set once a month (June–September 2019) for 24 h. All 205 mosquitoes tested negative for Dirofilaria spp. via PCR. The risk of endemisation of D. immitis in Austria (and other non-endemic countries in a similar situation) is very serious and its zoonotic potential should be communicated more strongly. To monitor a possible transmission of microfilariae from untreated or even untested positive dogs, e.g., in animal shelters, to mosquitoes in the near surroundings, frequent screening for Dirofilaria in mosquitoes should be used more intensively. Current knowledge on D. immitis should be integrated into daily veterinary practice and dog owners should be proactively educated, especially before traveling to endemic areas or adopting dogs from endemic countries. Animal shelters and animal welfare organizations should be provided with appropriate education and veterinary guidance regarding the testing and treatment of dogs imported from high-risk areas.

AI snapshot

Written from the paper’s full text.

TL;DR

In a survey of 115 Austrian shelter dogs and 205 mosquitoes near shelters, 11 dogs (9.6%) tested positive for Dirofilaria immitis antigen, all originating from Hungary, while all mosquitoes tested negative for Dirofilaria spp. by PCR. The authors conclude that the risk of D. immitis endemisation in Austria is serious and call for stronger screening, veterinary guidance, and owner education.

Key findings

  • Eleven of 115 shelter dogs (9.6%) tested positive for D. immitis; all positive dogs originated from Hungary. In total, 91% of dogs originated from countries endemic for dirofilariosis.
  • None of the dogs showed microfilaremia. Clinical staging of the 11 infected dogs found 8 with no or mild signs (stage one), 3 with stage-two signs, and 0 in stage three; echocardiography detected macrofilariae in the right ventricle or pulmonary arteries in 3 dogs.
  • All 205 mosquitoes tested negative for Dirofilaria spp. via PCR. Ten mosquito species were identified; seven species known or discussed as competent vectors for Dirofilaria spp. accounted for 202 individuals (98.5%).
  • The observed dog prevalence (9.6%) was comparable to some already-endemic countries cited by the authors, including Italy (8%), France (6.9%), and Hungary (11.3%).

Methods

  • Cross-sectional survey of 115 shelter dogs from 14 animal shelters in 5 Austrian federal states. Blood samples were screened by ELISA antigen-testing, PCR, and microscopical examination for microfilariae; clinical staging, echocardiography, and thoracic radiography were also performed in some dogs.
  • Mosquitoes were collected at 5 shelter sites in 4 Austrian federal states using CO2-baited traps set once a month (June–September 2019) for 24 h; 205 mosquitoes of 10 species were pooled by species and screened for Dirofilaria spp. by PCR.
  • Main analysis was descriptive: positivity counts and percentages; no inferential statistical analysis is reported.

Limitations

  • The paper states that mosquito trapping was relatively infrequent (once monthly for 24 h over four months), yielding a small sample size (n = 205).
  • The paper states that all dogs were reportedly treated prophylactically with macrocyclic lactones (milbemycin oxime), which likely suppressed microfilariae and almost excluded transmission to mosquitoes; it also notes that not all dogs had been in Austria long enough, so false-negative results during incubation cannot be excluded and true prevalence may have been higher.
  • Evident from the text: the mosquito collection year is inconsistent, with the Methods stating June–September 2018 while the Abstract and Results state June–September 2019.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.3390/pathogens10050550

Cites

Statistics

Nothing to recompute.

Claims the paper makes

0 of 97 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    115 dogs from fourteen animal shelters in five Austrian districts were included in the study.

    “Included in this study were 115 dogs living in fourteen animal shelters in five Austrian districts.”
    Quote in the paperNot a substantial claim
  • Findingown data

    All 205 mosquitoes tested negative for Dirofilaria spp. via PCR.

    “All 205 mosquitoes tested negative for Dirofilaria spp. via PCR.”
    Quote in the paperSubstantial claim
  • Findingown data

    Only one of the samples previously tested positive in ELISA antigen-testing also tested positive in the PCR assay.

    “Only one of the samples previously tested positive in ELISA antigen-testing also tested positive in the PCR assay.”
    Quote in the paperNot a substantial claim
  • Findingown data

    In total, 205 mosquitoes were caught in all five locations in June-September 2019.

    “In total, 205 mosquitoes were caught in all five locations in June–September 2019.”
    Quote in the paperNot a substantial claim
  • Findingown data

    91% of the dogs that originated from abroad came from countries known to be endemic for Dirofilaria spp.

    “Sixty-seven of the 115 dogs included in this study originated from abroad, 91% of these from countries known to be endemic for Dirofilaria spp.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim. 31
  • May combine two claims. 29

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Twenty-seven dogs were born in Austria and never left the country.

    “Twenty-seven dogs were born in Austria and never left the country, while 21 dogs were of unknown origin.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The 115 dogs originated from eleven different countries or were of unknown origin (18.3%).

    “The 115 dogs originated from eleven different countries or were of unknown origin (18.3%).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Most mosquitoes found were specified as Culex pipiens/torrentium (n = 185).

    “Most mosquitos found were specified as Culex pipiens/torrentium (n = 185).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Twenty-one dogs were of unknown origin.

    “Twenty-seven dogs were born in Austria and never left the country, while 21 dogs were of unknown origin.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Twenty individuals from nine other mosquito species were identified.

    “Twenty individuals from nine other species were identified (Table 4).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Of the 11 D. immitis-infected dogs, eight were stage one, three were stage two, and none were stage three.

    “The clinical staging of the D. immitis infected dogs (n = 11) resulted in eight dogs without clinical signs or with mild signs (stage one), three dogs showing clinical signs consistent with stage two and no dogs in stage three.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Twelve dogs were examined by echocardiography, and macrofilariae were found in the right ventricle or pulmonary arteries in three dogs.

    “Twelve dogs were examined by echocardiography and macrofilariae could be found in the right ventricle or pulmonary arteries in three dogs.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Besides Austria, most of the dogs came from (or had a travel history to) Hungary (23.5%), Spain (11.3%) and Croatia (7.0%), all three countries endemic to canine dirofilariosis.

    “Besides Austria, most of the dogs came from (or had a travel history to) Hungary (23.5%), Spain (11.3%) and Croatia (7.0%), all three countries endemic to canine dirofilariosis.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    Thoracic radiography was performed in twelve dogs and showed no abnormalities.

    “Thoracic radiography was performed in twelve dogs, showing no abnormalities.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    D. immitis can be introduced to non-endemic countries by dogs with a travel history to endemic regions and by dogs imported from endemic countries.

    “The parasite can be introduced to non-endemic countries by dogs with a travel history to endemic regions, as well as dogs imported from endemic countries [2,3].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [2] Genchi, 2011, Changing climate and changing vector-borne disease distribution: The example of Dirofilaria in Europe, Vet. Parasitol. source

      Not checked in the free run.

    • cites [3] Leschnik, 2008, Imported non-endemic, arthropod-borne and parasitic infectious diseases in Austrian dogs, Wien. Klin. Wochenschr. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The number of dogs with a travel history to endemic regions or imported from endemic countries is increasing.

    “Noteworthy in this context is the increasing number of dogs matching these criteria [4,5].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [4] Genchi, 2005, Is heartworm disease really spreading in Europe?, Vet. Parasitol. source

      Not checked in the free run.

    • cites [5] Sonnberger, 2020, Current trends in canine dirofilariosis in Austria-do we face a pre-endemic status?, Parasitol. Res. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The occurrence of D. repens can be considered a model for the estimated future distribution of D. immitis, because D. immitis seems to be spreading mainly to areas where D. repens has already established itself.

    “The occurrence of D. repens could be considered a model for the estimated future distribution of D. immitis, as the heartworm seems to be spreading mainly to the areas where D. repens has already established itself [4,8].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [4] Genchi, 2005, Is heartworm disease really spreading in Europe?, Vet. Parasitol. source

      Not checked in the free run.

    • cites [8] Capelli, 2018, Recent advances on Dirofilaria repens in dogs and humans in Europe, Parasites Vectors source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Since 1978, three infections with D. immitis have been reported in humans in Austria, causing pulmonary symptoms.

    “Since 1978, three infections with D. immitis have also been reported in humans in Austria, causing pulmonary symptoms in the patients [12].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [12] Auer, 2008, Der erste autochthone Fall einer subkutanen Dirofilariose in Österreich, Wiener klinische Wochenschrift source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Autochthonous D. repens infections have been found in Austria in mosquitoes, dogs, and humans.

    “The first autochthonous findings of D. repens in mosquitoes in Austria were made in 2012, and seven cases of cutaneous dirofilariosis in dogs were thought to be autochthonous infections until 2014, while the first autochthonous D. repens infection in humans was found even earlier, in 2006 [9,10,11].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [9] Fuehrer, H.-P., Auer, H., Leschnik, M., Silbermayr, K., Duscher, G., and Joachim, A. (2016). Dirofilaria in Humans, Dogs, and Vectors in Austria (1978–2014)—From Imported Pathogens to the Endemicity of Dirofilaria repens. PLoS Negl. Trop. Dis., 10. source

      Not checked in the free run.

    • cites [10] Silbermayr, 2014, Autochthonous Dirofilaria repens in Austria, Parasites Vectors source

      Not checked in the free run.

    • cites [11] Cuk, 2018, Xenomonitoring of Mosquitoes (Diptera: Culicidae) for the Presence of Filarioid Helminths in Eastern Austria, Can. J. Infect. Dis. Med. Microbiol.

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    By 2014, a total of 25 infections with D. immitis had been reported in dogs in Austria.

    “By 2014, a total of 25 infections with D. immitis had been reported in dogs in Austria.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [5] Sonnberger, 2020, Current trends in canine dirofilariosis in Austria-do we face a pre-endemic status?, Parasitol. Res. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Additional competent mosquito species might show an increasing occurrence in Europe because of climate change, potentially enabling autochthonous transmission in previously unaffected countries.

    “Additional competent species might show an increasing occurrence in Europe because of the proceeding climate change, potentially enabling autochthonous transmission in previously unaffected countries [1,3,6,7].”
    Quote in the paperNot a substantial claim0 of 4 sources checked
    • cites [1] 2012, Heartworm Disease (Dirofilaria immitis) and Their Vectors in Europe—New Distribution Trends, Front. Physiol.

      Not checked in the free run.

    • cites [3] Leschnik, 2008, Imported non-endemic, arthropod-borne and parasitic infectious diseases in Austrian dogs, Wien. Klin. Wochenschr. source

      Not checked in the free run.

    • cites [6] Genchi, 2009, Climate and Dirofilaria infection in Europe, Vet. Parasitol. source

      Not checked in the free run.

    • cites [7] Kronefeld, 2014, Molecular detection of Dirofilaria immitis, Dirofilaria repens and Setaria tundra in mosquitoes from Germany, Parasites Vectors source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Dirofilaria immitis is a filarioid parasite transmitted by mosquitoes and the causative agent of the zoonotic disease canine cardiopulmonary dirofilariosis.

    “Dirofilaria immitis, commonly known as “canine heartworm”, is a filarioid parasite transmitted by mosquitoes and the causative agent of a zoonotic disease, canine cardiopulmonary dirofilariosis [1].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [1] 2012, Heartworm Disease (Dirofilaria immitis) and Their Vectors in Europe—New Distribution Trends, Front. Physiol.

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    As climate change and globalization proceed, additional competent invasive mosquito vectors may become established in previously unaffected countries, facilitating autochthonous transmission of D. immitis.

    “As climate change and globalization proceed, additional competent invasive mosquito vectors, such as the Asian tiger mosquito (Aedes albopictus), may become established in previously unaffected countries, facilitating autochthonous transmission of D. immitis [1,3,6,7,24,25].”
    Quote in the paperNot a substantial claim0 of 6 sources checked
    • cites [1] 2012, Heartworm Disease (Dirofilaria immitis) and Their Vectors in Europe—New Distribution Trends, Front. Physiol.

      Not checked in the free run.

    • cites [3] Leschnik, 2008, Imported non-endemic, arthropod-borne and parasitic infectious diseases in Austrian dogs, Wien. Klin. Wochenschr. source

      Not checked in the free run.

    • cites [6] Genchi, 2009, Climate and Dirofilaria infection in Europe, Vet. Parasitol. source

      Not checked in the free run.

    • cites [7] Kronefeld, 2014, Molecular detection of Dirofilaria immitis, Dirofilaria repens and Setaria tundra in mosquitoes from Germany, Parasites Vectors source

      Not checked in the free run.

    • cites [24] Gratz, 2004, Critical review of the vector status of Aedes albopictus, Med. Vet. Entomol. source

      Not checked in the free run.

    • cites [25] Fuehrer, H.-P., Schoener, E., Weiler, S., Barogh, B.S., Zittra, C., and Walder, G. (2020). Monitoring of alien mosquitoes in Western Austria (Tyrol, Austria, 2018). PLoS Negl. Trop. Dis., 14. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    A particularly strong increase in the number of D. immitis infections is currently observed in Eastern Europe.

    “A particularly strong increase in the number of infections is currently observed in Eastern Europe [4,23].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [4] Genchi, 2005, Is heartworm disease really spreading in Europe?, Vet. Parasitol. source

      Not checked in the free run.

    • cites [23] Genchi, 2020, The prevalence of Dirofilaria immitis and D. repens in the Old World, Vet. Parasitol. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    According to shelter managements, all dogs included in this study were treated prophylactically with macrocyclic lactones (milbemycin oxime) at a minimum frequency of four times a year.

    “According to the shelter managements, all dogs included in this study were treated prophylactically with macrocyclic lactones (milbemycin oxime) at a minimum frequency of four times a year.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    In Europe, D. immitis is predominantly found in southern countries such as France, Greece, Italy, Portugal and Spain.

    “In Europe, the parasite is predominantly found in southern countries, such as France, Greece, Italy, Portugal and Spain.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [4] Genchi, 2005, Is heartworm disease really spreading in Europe?, Vet. Parasitol. source

      Not checked in the free run.

    • cites [23] Genchi, 2020, The prevalence of Dirofilaria immitis and D. repens in the Old World, Vet. Parasitol. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Hungary is one of the countries with the highest prevalence for dirofilariosis in Europe.

    “which is also one of the countries with the highest prevalence for dirofilariosis in Europe [26].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [26] Bacsadi, 2016, Retrospective study on the distribution of Dirofilaria immitis in dogs in Hungary, Vet. Parasitol. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Attention from the public and the veterinary profession did not increase to the same extent as the growing concern.

    “Unfortunately, the attention from the public at large and the veterinary profession, in particular, did not increase to the same extent [20,21,22].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [20] Strube, 2018, Simple, but not easy—Opportunities and challenges from teachers’ and students’ perspectives in the 21st century of veterinary parasitology teaching, Vet. Parasitol. source

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    • cites [21] Strube, 2019, Survey of German pet owners quantifying endoparasitic infection risk and implications for deworming recommendations, Parasites Vectors source

      Not checked in the free run.

    • cites [22] Lohner, 2020, Zoonotische Parasiten von Hund und Katze—Wissensstand von TierbesitzerInnen und Studierenden der Veterinärmedizin, Wiener Tierärztliche Monatsschrift

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  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    In 2017, the BMSGPK listed 37 approved animal shelters in Austria.

    “The Federal Ministry of Social Affairs, Health, Long-Term Care and Consumer Protection (Bundesministerium für Soziales, Gesundheit, Pflege und Konsumentenschutz, BMSGPK, Vienna, Austria) listed 37 approved animal shelters in 2017 [18].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [18] Bundesministerium für Soziales, Gesundheit, Pflege und Konsumentenschutz (2021, May 01). Tierheime in Österreich. Available online: https://www.verbrauchergesundheit.gv.at/tiere/tierschutz/heime/tierheime.html.

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Dogs with a travel history to endemic regions, as well as dogs imported from endemic countries, can introduce D. immitis to non-endemic countries.

    “Dogs with a travel history to endemic regions, as well as dogs imported from endemic countries, can introduce the parasite to non-endemic countries.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [2] Genchi, 2011, Changing climate and changing vector-borne disease distribution: The example of Dirofilaria in Europe, Vet. Parasitol. source

      Not checked in the free run.

    • cites [3] Leschnik, 2008, Imported non-endemic, arthropod-borne and parasitic infectious diseases in Austrian dogs, Wien. Klin. Wochenschr. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Infections with D. immitis are of growing concern in Central Europe, as D. immitis has shown a rapidly increasing prevalence over the past few years.

    “Infections with the zoonotic parasite Dirofilaria immitis are of growing concern in Central Europe, as D. immitis has shown a rapidly increasing prevalence over the past few years.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [20] Strube, 2018, Simple, but not easy—Opportunities and challenges from teachers’ and students’ perspectives in the 21st century of veterinary parasitology teaching, Vet. Parasitol. source

      Not checked in the free run.

    • cites [21] Strube, 2019, Survey of German pet owners quantifying endoparasitic infection risk and implications for deworming recommendations, Parasites Vectors source

      Not checked in the free run.

    • cites [22] Lohner, 2020, Zoonotische Parasiten von Hund und Katze—Wissensstand von TierbesitzerInnen und Studierenden der Veterinärmedizin, Wiener Tierärztliche Monatsschrift

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    A survey of the literature revealed quite similar study results in other countries: in two studies from Germany, most cases of D. immitis were imported from Spain, Greece, Hungary and Italy, while in a retrospective study from Austria, most infected dogs originated from Hungary or Greece.

    “A survey of the literature revealed quite similar study results in other countries. In two studies from Germany, most cases of D. immitis were imported from Spain, Greece, Hungary and Italy, while in a retrospective study from Austria, most infected dogs originated from Hungary or Greece [5,27,28].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [5] Sonnberger, 2020, Current trends in canine dirofilariosis in Austria-do we face a pre-endemic status?, Parasitol. Res. source

      Not checked in the free run.

    • cites [27] Volkmann, 2019, Retrospective evaluation of vector-borne infections in dogs imported from the Mediterranean region and southeastern Europe (2007–2015), Parasites Vectors source

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    • cites [28] Pantchev, 2011, Diagnosis of imported canine filarial infections in Germany 2008—2010, Parasitol. Res. source

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  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    According to the manufacturer's data, the SNAP 4Dx Plus test shows a sensitivity of 99.0% and a specificity of 99.3%.

    “According to the manufacturer’s data, the SNAP 4Dx Plus test (SNAP 4Dx Plus-Test, IDEXX GmbH, Kornwestheim, Germany), which is frequently used in Austria and was also used in the present study, shows a sensitivity of 99.0% and a specificity of 99.3% [40].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [40] IDEXX Laboratories, Inc. (2021, May 01). SNAP 4Dx Plus Test: Test Accuracy. Available online: https://www.idexx.de/files/snap-4dx-plus-test-accuracy.pdf.

      Not checked in the free run.

  • May combine two claims.

    Study design and conductcitation

    In the present study, the use of a native blood smear was found to be sufficient, as PCR was additionally performed.

    “In the present study, the use of a native blood smear was found to be sufficient, as PCR was additionally performed [34,35,36].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [34] Martini, 1991, Diagnosis of canine filariosis: Relative sensitivity and specificity of some haematological techniques, Angew. Parasitol.

      Not checked in the free run.

    • cites [35] Eslami, 2007, Evaluation of different methods for diagnosis of Dirofilaria immitis, Pak. J. Biol. Sci. source

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    • cites [36] Mylonakis, 2004, Comparative methodology for the detection and differentiation of circulating microfilariae of Dirofilaria immitis in the dog, J. Helminthol. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In Austria, the endemisation of D. repens already appears to be concluded and could be considered a model for the expected future distribution of D. immitis, as the heartworm seems to be spreading mainly to the areas where D. repens has already established itself.

    “In Austria, the endemisation of D. repens already appears to be concluded and could be considered a model for the expected future distribution of D. immitis, as the heartworm seems to be spreading mainly to the areas where D. repens has already established itself [1,4,8,9].”
    Quote in the paperNot a substantial claim0 of 4 sources checked
    • cites [1] 2012, Heartworm Disease (Dirofilaria immitis) and Their Vectors in Europe—New Distribution Trends, Front. Physiol.

      Not checked in the free run.

    • cites [4] Genchi, 2005, Is heartworm disease really spreading in Europe?, Vet. Parasitol. source

      Not checked in the free run.

    • cites [8] Capelli, 2018, Recent advances on Dirofilaria repens in dogs and humans in Europe, Parasites Vectors source

      Not checked in the free run.

    • cites [9] Fuehrer, H.-P., Auer, H., Leschnik, M., Silbermayr, K., Duscher, G., and Joachim, A. (2016). Dirofilaria in Humans, Dogs, and Vectors in Austria (1978–2014)—From Imported Pathogens to the Endemicity of Dirofilaria repens. PLoS Negl. Trop. Dis., 10. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    So far, DNA of D. repens has been examined in pools of An. algeriensis and An. maculipennis complex in Austria near the Hungarian border, and no DNA of D. immitis has been found to date.

    “So far, DNA of D. repens has been examined in pools of An. algeriensis and An. maculipennis complex in Austria near the Hungarian border, and no DNA of D. immitis has been found to date [11].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [11] Cuk, 2018, Xenomonitoring of Mosquitoes (Diptera: Culicidae) for the Presence of Filarioid Helminths in Eastern Austria, Can. J. Infect. Dis. Med. Microbiol.

      Not checked in the free run.

  • May combine two claims.

    Interpretationown data

    The PCR test can be negative in dogs pretreated with milbemycin, resulting in no microfilariae circulating in the blood at the time of sampling, even though infection with macrofilariae could be detected by ELISA antigen-testing.

    “However, as can be seen in the present study, the PCR test can be negative in dogs pretreated with milbemycin, resulting in no microfilariae circulating in the blood at the time of sampling, even though infection with macrofilariae could be detected by the ELISA antigen-test.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    According to literature, approximately 85% of dogs infected with D. immitis show radiographically more or less specific pathologies in the area of the heart and lungs.

    “Interestingly, no abnormalities were found in any of the radiographs of the infected dogs, even though, according to literature, approximately 85% of dogs infected with D. immitis show radiographically more or less specific pathologies in the area of the heart and lungs [48,49].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [48] Bowman, 2009, Heartworm biology, treatment, and control, Vet. Clin. North Am. Small Anim. Pract. source

      Not checked in the free run.

    • cites [49] Mavropoulou, 2014, Clinical assessment of post-adulticide complications in Dirofilaria immitis-naturally infected dogs treated with doxycycline and ivermectin, Vet. Parasitol. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    The absence of microfilaremia in the examined dogs might be due to occult infections, infection with male worms only, or applied prophylactic microfilaricidal therapy.

    “As the screening for microfilariae in native blood smears shows a sensitivity of 80–89%, this outcome might be due to occult infections, infection with male worms only, or, even more likely, applied prophylactic microfilaricidal therapy [15,33], as was reported from all animal shelters in this study.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [15] Boreham, P.F.L., and Atwell, R.B. (2018). Dirofilariasis, CRC Press. source

      Not checked in the free run.

    • cites [33] World Small Animal Veterinary Association (1992, January 24–27). Spreading of Dirofilaria immitis infections in dogs and cats in Italy. Proceedings of the XVII WSAVA World Congress, Roma, Italy.

      Not checked in the free run.

  • May combine two claims.

    Study design and conductnone given

    Although all dogs included in this study were at least six months old, not all dogs had been located in Austria for an equivalently long period.

    “Additionally, although all dogs included in this study were at least six months old (to take the incubation period into account), not all dogs had been located in Austria for an equivalently long period.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    These results are consistent with the literature, noting many altogether asymptomatic cases of canine dirofilariosis and a long, symptom-free incubation period.

    “These results are consistent with the literature, noting many altogether asymptomatic cases of canine dirofilariosis and a long, symptom-free incubation period (which are also part of the problem in successful monitoring and prevention of the introduction of D. immitis to non-endemic countries) [17,48].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [17] Schnieder, T. (2006). Veterinärmedizinische Parasitologie: 92 Tabellen, 3 Übersichten, Parey. source

      Not checked in the free run.

    • cites [48] Bowman, 2009, Heartworm biology, treatment, and control, Vet. Clin. North Am. Small Anim. Pract. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    It cannot be excluded that some dogs tested (false-) negative during their incubation period despite being infected with D. immitis, and the actual prevalence in the study group may have been higher.

    “Therefore, it cannot be excluded that some of the dogs tested (false-) negative during their incubation period despite being infected with D. immitis, and the actual prevalence in the study group may have been higher.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    Potential competent mosquito vectors were found at all shelter sites, including three animal shelters housing D. immitis-positive dogs, which would theoretically enable transmission from the dogs to a vector during a blood meal.

    “Potential competent mosquito vectors were found at all shelter sites, including three animal shelters housing D. immitis-positive dogs, which would theoretically enable transmission from the dogs to a vector during a blood meal.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    An increasing spread of dirofilarial infections can be observed in other countries, such as Greece, Turkey, Bulgaria and Romania.

    “In addition, an increasing spread of dirofilarial infections can be observed in other countries, such as Greece, Turkey, Bulgaria and Romania [23,31,32].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [23] Genchi, 2020, The prevalence of Dirofilaria immitis and D. repens in the Old World, Vet. Parasitol. source

      Not checked in the free run.

    • cites [31] Radev, 2016, Prevalence of gastrointestinal parasites and Dirofilaria spp. in stray dogs from some regions in bulgaria, Bulg. J. Vet. Med. source

      Not checked in the free run.

    • cites [32] Iliev, 2017, Retrospective analysis in helminthic and protozoan infections in dogs and cats in Bulgaria, Bulg. J. Vet. Med.

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Various in-house test systems based on ELISA antigen-testing have an average sensitivity of up to 84% and a specificity of about 97%, and are suitable for diagnosis even in dogs with a low worm burden.

    “These results are consistent with the literature, showing that various in-house test systems based on ELISA antigen-testing have an average sensitivity of up to 84% and a specificity of about 97%, and are suitable for diagnosis even in dogs with a low worm burden [37,38,39].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [37] Courtney, 2001, Comparison of heartworm antigen test kit performance in dogs having low heartworm burdens, Vet. Parasitol. source

      Not checked in the free run.

    • cites [38] Atkins, 2003, Comparison of results of three commercial heartworm antigen test kits in dogs with low heartworm burdens, J. Am. Vet. Med. Assoc. source

      Not checked in the free run.

    • cites [39] Lee, 2011, Evaluation of a new in-clinic method for the detection of canine heartworm antigen, Vet. Parasitol. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    The noticeable increase in the prevalence of dirofilariosis in imported shelter dogs is a serious risk factor for endemisation, particularly because of the presence of several mosquito species in Austria potentially able to transmit Dirofilaria spp. and the relatively frequent occurrence of these species.

    “Still, the noticeable increase in the prevalence of dirofilariosis in imported shelter dogs is a serious risk factor for endemisation, particularly because of the presence of several mosquito species in Austria potentially able to transmit Dirofilaria spp. and the relatively frequent occurrence of these species.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Consistent with the data collected in the present study, the incidence and geographical distribution of heartworm disease in Hungarian dogs have risen since 2012.

    “Likewise, consistent with the data collected in the present study, the incidence and geographical distribution of heartworm disease in Hungarian dogs have risen since 2012 [29].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [29] Farkas, 2014, Seroprevalence of some vector-borne infections of dogs in Hungary, Vector Borne Zoonotic Dis. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Human infection with D. immitis can occur while traveling to endemic regions, from one's own infected dog, or from infected dogs in the surrounding neighborhood.

    “The risk of human infection while traveling to endemic regions, by infection by one’s own dog, if infected, or infected dogs in the surrounding neighborhood, and the potential severity of human cases should therefore be communicated to the public more strongly.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [52] Bazzocchi, 2008, Combined ivermectin and doxycycline treatment has microfilaricidal and adulticidal activity against Dirofilaria immitis in experimentally infected dogs, Int. J. Parasitol. source

      Not checked in the free run.

    • cites [53] Simón, F., Kartashev, V., González-Miguel, J., Rivera, A., Diosdado, A., Gómez, P.J., Morchón, R., Siles-Lucas, M., Bastrikov, N., and Ilyasov, B. (2017). Fifth European Dirofilaria and Angiostrongylus Days (FiEDAD) 2016. Parasites Vectors, 10. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    The isolated DNA was screened twice for the presence of filarioid DNA with conventional PCR, applying two different protocols.

    “The isolated DNA was then screened twice for the presence of filarioid DNA with conventional PCR, applying two different protocols”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [17] Schnieder, T. (2006). Veterinärmedizinische Parasitologie: 92 Tabellen, 3 Übersichten, Parey. source

      Not checked in the free run.

    • cites [18] Bundesministerium für Soziales, Gesundheit, Pflege und Konsumentenschutz (2021, May 01). Tierheime in Österreich. Available online: https://www.verbrauchergesundheit.gv.at/tiere/tierschutz/heime/tierheime.html.

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    ELISA antigen-testing was performed in all 115 dogs.

    “ELISA antigen-testing could be performed in all 115 dogs and PCR testing in 111 dogs.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    All dogs included in this study were regularly treated prophylactically with macrocyclic lactones (milbemycin oxime), which almost excluded the transmission of microfilariae to mosquitoes during a blood meal, since macrocyclic lactones have a microfilaricidal effect.

    “Furthermore, it must be considered that, according to the animal shelters’ managements, all dogs included in this study were regularly treated prophylactically with macrocyclic lactones (milbemycin oxime), which almost excluded the transmission of microfilariae to mosquitoes during a blood meal, since macrocyclic lactones have a microfilaricidal effect.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Macrocyclic lactones have a microfilaricidal effect.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    Dogs that tested negative in the rapid test kit using unheated serum samples were re-tested using heated serum to exclude false-negative results.

    “The dogs that tested negative in the rapid test kit using unheated serum samples were re-tested using heated serum to exclude false-negative results.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    The identification microchip of each dog was scanned if present to ensure distinctive identification.

    “The identification microchip of each dog was scanned if present to ensure distinctive identification.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    Mosquitoes were pooled by species following the identification keys by BECKER 2010.

    “The mosquitoes were then pooled by species following the identification keys by BECKER 2010 [54].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [54] Becker, N., Petric, D., Zgomba, M., Boase, C., Madon, M.B., Dahl, C., and Kaiser, A. (2010). Mosquitoes and Their Control, Springer. [2nd ed.]. source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductown data

    PCR testing was performed in samples of 105 dogs.

    “PCR testing was performed in samples of 105 dogs.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    PCR testing was performed in 111 dogs.

    “ELISA antigen-testing could be performed in all 115 dogs and PCR testing in 111 dogs.”
    Quote in the paperNot a substantial claim
51 of 51

  • The paper relies on this without support.

    The countries mentioned above are neighboring countries of Austria or are frequently visited travel destinations, and are also strongly represented among animal welfare organizations that bring shelter and stray dogs to Austria.

    “The countries mentioned above are neighboring countries of Austria or are frequently visited travel destinations, and are also strongly represented among animal welfare organizations that bring shelter and stray dogs to Austria.”

  • The paper relies on this without support.

    Macrocyclic lactones have a microfilaricidal effect.

    “since macrocyclic lactones have a microfilaricidal effect.”

  • The paper relies on this without support.

    Regular application of microfilaricides can help prevent transmission from infected dogs to mosquitoes.

    “Regular application of microfilaricides could help prevent transmission from infected dogs to mosquitoes.”
3 of 3

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • PCR sample counts disagree

    Major

    The general methods state that PCR testing was performed in 111 dogs, but the PCR methods give 105 dogs.

  • ELISA rapid-test count exceeds the described testing groups

    Minor

    The results say 111 dogs received an ELISA rapid test kit, with dogs tested by an external laboratory described separately. The methods instead divide all 115 dogs into five tested by shelter staff, eight by an external laboratory, and 102 remaining dogs; even if the five shelter tests used rapid kits, that allows at most 107 rapid-kit tests.

  • Mosquito collection year differs between sections

    Minor

    The results date the mosquito collection to June-September 2019, while the collection method dates it to June-September 2018.

  • Endemic-country origin reported as 91% of incompatible groups

    Minor

    The paper says 91% of all 115 dogs originated from endemic countries, but later says 91% of the 67 dogs from abroad did. The latter is about 61 dogs, not about 105 dogs.

4 of 4

The citation lists haven’t been fetched yet

References 47 · Cited by 19

Research works printed but not linked: 5

  1. Schlager, A. (2003). Erhebungen über den Status von Tierheimen, Tierasylen und Gnadenhöfen in Österreich. [Doctoral Thesis, Veterinärmedizinische Universität Wien].
  2. Lohner, 2020, Zoonotische Parasiten von Hund und Katze—Wissensstand von TierbesitzerInnen und Studierenden der Veterinärmedizin, Wiener Tierärztliche Monatsschrift, 107, 243
  3. Glaser, 1998, Hundetourismus und–Import: Eine Umfrage in Deutschland zu Ausmaß sowie Spektrum und Präferenz der Aufenthalts- bzw. Herkunftsländer, Tierärztliche Praxis, 26, 197
  4. Iliev, 2017, Retrospective analysis in helminthic and protozoan infections in dogs and cats in Bulgaria, Bulg. J. Vet. Med., 20, 389
  5. World Small Animal Veterinary Association (1992, January 24–27). Spreading of Dirofilaria immitis infections in dogs and cats in Italy. Proceedings of the XVII WSAVA World Congress, Roma, Italy.

Authors
Sonnberger, K., Fuehrer, H.-P., Sonnberger, B. W., & Leschnik, M.
Affiliations
University of Veterinary Medicine Vienna (AT)
Corresponding author
Sonnberger, Karin
ORCID
Venue
Pathogens
Publisher
MDPI AG
Published
2021-05-02
Volume
10
Issue
5
Pages
550
ISSN
2076-0817 (ISSN-L)
DOI
10.3390/pathogens10050550
PMC
PMC8147468
OpenAlex
W3159764553
Cited by
19
References
47
Citations by year
2026: 2 · 2025: 2 · 2024: 4 · 2023: 1 · 2022: 5 · 2021: 5
FWCI
1.19
Type
journal article
Language
en
Open access
Licence
Locations
  • Pathogens (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Topics
  • Health Sciences › Medicine › Infectious Diseases › Parasitic Diseases Research and Treatment
  • Health Sciences › Medicine › Public Health, Environmental and Occupational Health › Research on Leishmaniasis Studies
  • Health Sciences › Veterinary › Small Animals › Helminth infection and control
Keywords
Dirofilaria immitis, canine heartworm disease, shelter dogs, mosquitoes, imported dogs, microfilariae, zoonotic transmission, animal shelters

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