CoChat
Sign Up
Cited by 21Parasitic Diseases Research and TreatmentHelminth infection and controlResearch on Leishmaniasis Studies

First Autochthonous Infection of a Cat with Dirofilaria immitis in Austria

Open access
Kulmer, Lisa-Maria, Unterköfler, Maria Sophia, Fuehrer, Hans-Peter, Janovska, Varvara, Pagac, Matus, Svoboda, Michaela, Venco, Luigi, Leschnik, Michael·2021·Pathogens
DOI 10.3390/pathogens10091104PMC PMC8466588
Open this paper in CoChat — free accountOpen PDF

Abstract

This case report is about a seven-year-old male neutered European Shorthair cat infected by Dirofilaria immitis as the first reported autochthonous Dirofilaria immitis infection in Austria. There was no history of periods abroad. Echocardiography showed suspected D. immitis in the right cardiac chamber with increased pulmonary pressure and ascites. Surgical removal of the heartworms was performed. Twenty adult heartworms were removed by transvenous jugular approach under general anesthesia and stored in 4% formalin. Five out of 20 specimens were examined via light and stereomicroscopy and feline heartworm infection was confirmed. Amplification of a 203 bp or 724 bp fragment of the cytochrome c oxidase subunit I gene was unsuccessful. After surgery the cat developed acute renal failure but recovered quickly. One year later, the cat underwent a control examination including echocardiography and blood work. There were no more D. immitis detectable at echocardiography. Lung pressure was mildly increased. Complete blood count and creatinine were unremarkable. The Knott’s test and Dirofilaria-Antigen-test produced negative results. The cat did not show any clinical signs during the follow-up period. The aim of this case report is to highlight the growing risk of acquiring infection with D. immitis not only for Austrian dogs, but also for cats. This case report represents the first report of autochthonous D. immitis infection in Austria. Moreover, even if the prognosis in cats with caval syndrome due to feline heartworm disease is guarded to poor, surgical removal of the filariae can be a successful treatment option.

AI snapshot

Written from the paper’s full text.

TL;DR

This case report describes a seven-year-old neutered male European Shorthair cat in Burgenland, Austria, with autochthonous *Dirofilaria immitis* infection and no history of travel abroad. Twenty adult heartworms were surgically removed, the cat recovered, and at 16 months no *D. immitis* were detectable.

Key findings

  • The cat was reported as the first autochthonous *D. immitis* infection in a cat in Austria; it lived at 47°34′57.443″ N, 16°32′33.673″ E, approximately 4.5 km from the Hungarian border, with unrestricted outdoor access and no periods abroad.
  • Echocardiography showed suspected *D. immitis* in the right cardiac chamber with severe right atrial dilatation; surgery removed 20 adult worms, with two to three dirofilariae remaining in the right atrium after further attempts failed.
  • Five of 20 specimens were examined morphologically: three female and two male. Females were 212–250 mm long and 0.74–1.08 mm wide; males were 97–116 mm long and 0.63–0.66 mm wide, with one male missing its tail. PCR amplification of a 203 bp or 724 bp cytochrome c oxidase subunit I fragment was unsuccessful.
  • Postoperatively the cat developed acute renal failure with creatinine 5.1 mg/dL and haematocrit 12.8%; it improved and was discharged three days later with creatinine 3.2 mg/dL and haematocrit 12%. At 16 months, no heartworms were detectable, Knott’s test and *Dirofilaria* antigen test were negative, haematocrit was 30.5%, and creatinine was 1.9 mg/dL.

Methods

  • Single clinical case report of a seven-year-old neutered male European Shorthair cat, 6 kg, referred in March 2020 for echocardiography after dyspnoea and increased abdominal circumference.
  • Diagnostic workup included clinical examination, thoracic and abdominal radiographs, echocardiography, complete blood count and blood chemistry, FeLV/FIV Snap test, surgical removal via transvenous right jugular approach under general anaesthesia, and morphological examination of five formalin-stored worms by light and stereomicroscopy.
  • Molecular identification attempted DNA extraction from formalin-fixed specimens and PCR for 203 bp and 724 bp fragments of the cytochrome c oxidase subunit I gene; follow-up examination occurred 16 months after surgery.

Limitations

  • The paper states that no antigen or antibody test for *D. immitis* was performed before surgery due to the owner’s cost restrictions, and no microfilaraemia test was performed during initial diagnosis.
  • The paper states that it cannot completely rule out that the cat crossed the Hungarian border and became infected there, or that mosquitoes crossed the border and infected the cat at its home farm, although it considers this improbable.
  • The paper states that DNA extraction from formalin-fixed tissue is challenging and PCR was unsuccessful; no further extraction was attempted. Evident from the text: this is a single case report, so it cannot establish prevalence or generalizable risk, and the autochthonous designation rests on history and location rather than direct proof of local transmission.

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

Integrity signals

Registry

Crossref · 10.3390/pathogens10091104

Cites

42 of 42 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 84 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Twenty adult heartworms were removed by transvenous jugular approach under general anesthesia.

    “Twenty adult heartworms were removed by transvenous jugular approach under general anesthesia and stored in 4% formalin.”
    • Also stated in: § 2.3. Surgical Removal of D. immitis · plain
      “By use of this technique, which was described by Glaus et al., 1995 [16] the successful removal of 20 adult worms was possible (Figure 3, Video S1).”
    Quote in the paperNot a substantial claim
  • Findingown data

    The cat did not show any clinical signs during the follow-up period.

    “The cat did not show any clinical signs during the follow-up period.”
    • Also stated in: § 2.6. Follow Up · plain
      “The owner reported that the cat was not showing any clinical signs despite of infrequent, spontaneous coughing and receiving the prescribed medication daily.”
    Quote in the paperNot a substantial claim
  • Findingown data

    Comparing the two echocardiograms, the cat's hemodynamic status significantly improved with increased left ventricle preload.

    “Comparing the two echocardiograms the cat’s hemodynamic status significantly improved (Table 2) with increased left ventricle preload.”
    Quote in the paperNot a substantial claim
  • Findingown data

    The cat showed right atrial and right ventricular enlargement.

    “The cat also showed right atrial as well as right ventricular enlargement, which underlined our suspected diagnosis of FHWD.”
    Quote in the paperNot a substantial claim
  • Findingnone given

    The cat developed acute kidney failure postoperatively.

    “The cat developed acute kidney failure postoperatively.”
    Quote in the paperNot a substantial claim
  • May combine two claims. 34
  • The quote only partly states this claim. 2
  • Classified as probably not a substantial claim. 39

  • May combine two claims. The quote only partly states this claim.

    Findingown data

    The cat was a seven-year-old male neutered European Shorthair, 6 kg, with no history of periods abroad.

    “This case report is about a seven-year-old male neutered European Shorthair cat infected by Dirofilaria immitis as the first reported autochthonous Dirofilaria immitis infection in Austria. There was no history of periods abroad.”
    • Also stated in: § 2. Case Report · plain
      “A male neutered European Shorthair cat, seven years of age, 6 kg weight, was referred to the Veterinary Hospital Parndorf in the province of Burgenland, Austria for echocardiography in March 2020 (Figure 1).”
    • Also stated in: § 2. Case Report · plain
      “The cat was neither regularly vaccinated nor dewormed and had no history of periods abroad.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The cat had unrestricted outdoor access and had spent its lifetime in the same area in Burgenland, Austria (47°34′57.443′′ N, 16°32′33.673′′ E).

    “At this time, the cat was the only animal in the household and had unrestricted outdoor access. The cat was in possession since kitten age, spending its lifetime in the same area, which is 47°34′57.443″ N, 16°32′33.673″ E.”
    Quote in the paperSubstantial claim

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

    Findingown data

    Amplification of a 203 bp or 724 bp fragment of the cytochrome c oxidase subunit I gene was unsuccessful.

    “Amplification of a 203 bp or 724 bp fragment of the cytochrome c oxidase subunit I gene was unsuccessful.”
    • Also stated in: § 2.4. Identification of Dirofilaria Specimens · plain
      “Amplification of a 203 bp or 724 bp fragment of the cytochrome c oxidase subunit I gene was unsuccessful.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Echocardiography at initial presentation showed suspected D. immitis in the right cardiac chamber with increased pulmonary pressure and ascites.

    “Echocardiography showed suspected D. immitis in the right cardiac chamber with increased pulmonary pressure and ascites.”
    • Also stated in: § 2.1. Echocardiography · hedged
      “The right atrium showed severe dilatation, and several double lined hyperechoic echoes close the tricuspid valve were seen (Figure 2). The suspected diagnosis based on the echocardiographic findings and the clinical signs was an infection with D. immitis.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    After surgery the cat developed acute renal failure but recovered quickly.

    “After surgery the cat developed acute renal failure but recovered quickly.”
    • Also stated in: § 2.5. Postoperative Course · hedged
      “After surgery, the cat’s creatinine increased to 5.1 mg/dL and the haematocrit decreased to 12.8%—but showed still high regeneration with a reticulocyte count of 158.7 G/L. It was suspected that the cat had an episode of acute kidney failure due to the removal of the heartworms.”
    Quote in the paperNot a substantial claim

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

    Findingnone given

    The cat in this case report lives in Horitschon, approximately 4.5 km linear distance from the Hungarian border.

    “The cat in this case report lives in Horitschon, which is approximately 4.5 km linear distance from the Hungarian border.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingcitation

    At initial presentation, the cat showed dyspnoea, ascites and double hyperechoic parallel lines in echocardiography.

    “At initial presentation, the cat showed dyspnoea, ascites and double hyperechoic parallel lines in the echocardiography, which is the typical presentation for D. immitis in echocardiography [26].”
    • Also stated in: § 2. Case Report · plain
      “Prior to admittance, the cat had a short history of dyspnoea and increased abdominal circumference.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    One year later, control examination showed no D. immitis detectable at echocardiography, mildly increased lung pressure, unremarkable complete blood count and creatinine, and negative Knott's and Dirofilaria antigen tests.

    “One year later, the cat underwent a control examination including echocardiography and blood work. There were no more D. immitis detectable at echocardiography. Lung pressure was mildly increased. Complete blood count and creatinine were unremarkable. The Knott’s test and Dirofilaria-Antigen-test produced negative results.”
    • Also stated in: § 2.6. Follow Up · plain
      “No heartworm was detectable (Figure 8).”
    • Also stated in: § 2.6. Follow Up · plain
      “the Knott’s test to detect microfilaria was negative. In addition, the Heartworm-Snap-Test® (Idexx Laboratories, Westbrook, ME, USA) showed a negative result.”
    Quote in the paperNot a substantial claim

  • May combine two claims. The quote only partly states this claim.

    Findingown data

    Five out of 20 specimens were examined via light and stereomicroscopy, and all morphological features were compatible with adult stages of D. immitis.

    “Five out of 20 specimens were examined via light and stereomicroscopy and feline heartworm infection was confirmed.”
    Quote in the paperSubstantial claim

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

    Findingown data

    At follow-up, complete blood count showed no abnormalities with a haematocrit of 30.5% and creatinine of 1.9 mg/dL.

    “Complete blood count and creatinine were repeated, and CBC showed no abnormalities with a haematocrit of 30.5% and creatinine of 1.9 mg/dL (Table 1).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The thoracic radiographs at follow-up showed a moderate bronchointerstitial lung pattern without enlarged pulmonary arteries.

    “The thoracic radiographs showed a moderate bronchointerstitial lung pattern without enlarged pulmonary arteries (Figure 7).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    At follow-up, the cat showed tricuspid insufficiency (2.8 m/s), mild mitral insufficiency, and pulmonary artery flow Vmax 1.1 m/s, probably suggesting mild pulmonary hypertension.

    “The cat showed a tricuspid insufficiency (2.8 m/s), a mild mitral insufficiency and a pulmonary artery flow of Vmax 1.1 m/s (probably suggesting mild pulmonary hypertension).”
    Quote in the paperNot a substantial claim

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

    Findingown data

    The cat tested positive for feline leukemia virus (FeLV).

    “The Combo+ Snaptest® (Idexx Laboratories, Westbrook, ME, USA) for infection with feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) showed a positive result for FeLV.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The cat showed severe hyperchromic, macrocytic regenerative anaemia and mildly increased leucocytes with mildly increased neutrophils, lymphocytes and monocytes.

    “The cat showed a severe hyperchromic, macrocytic regenerative anaemia. What is more, the cat showed a mildly increased count of leucocytes with mildly increased neutrophils, lymphocytes and monocytes.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingcitation

    A definitive morphological identification was possible and comparable to other publications.

    “A definitive morphological identification was possible and comparable to other publications [41].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [41] Furtado, 2010, Morphological Redescription of Dirofilaria immitis, J. Parasitol. source

      Not checked in the free run.

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

    Findingown data

    Felichek-3 showed negative results for feline heartworm antibodies, feline immunodeficiency virus antibody, and feline leukaemia virus antigen.

    “Felichek-3® (Bionote), a chromatographic immunoassay showed negative results for feline heartworm antibodies as well as feline immunodeficiency virus antibody and feline leukaemia virus antigen.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The cat showed diffuse bronchointerstitial lung pattern and enlarged pulmonary arteries in thoracic radiographs.

    “What is more, the cat showed diffuse bronchointerstitial lung pattern and enlarged pulmonary arteries in the thoracic radiographs, which were taken by the referral vet.”
    Quote in the paperNot a substantial claim

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

    Findingown data

    The cat showed severe hyperchromic, macrocytic regenerative anaemia.

    “The cat showed also severe hyperchromic, macrocytic regenerative anaemia.”
    Quote in the paperNot a substantial claim

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

    Findingown data

    The cat's medical condition improved and it was sent home three days after surgery with a creatinine of 3.2 mg/dL and a stable haematocrit of 12%.

    “Fortunately, the cat’s medical condition improved, and it was sent home three days after surgery with a creatinine of 3.2 mg/dL and a stable haematocrit of 12%.”
    Quote in the paperNot a substantial claim

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

    Findingnone given

    The cat showed negative results for FeLV 16 months after surgery.

    “In addition, the cat showed negative results for FeLV 16 months after surgery.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    D. immitis infects mainly dogs but also cats, ferrets, wild carnivores and humans, and more than 70 different species of culicid mosquitoes can act as vectors.

    “D. immitis infects mainly dogs but also cats, ferrets, wild carnivores and humans, and more than 70 different species of culicid mosquitos can act as vectors [2,3].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [2] Miguel, 2012, Heartworm Disease (Dirofilaria immitis) and Their Vectors in Europe—New Distribution Trends, Front. Physiol.

      Not checked in the free run.

    • cites [3] Mellado, 2012, Human and Animal Dirofilariasis: The Emergence of a Zoonotic Mosaic, Clin. Microbiol. Rev. source

      Not checked in the free run.

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

    Interpretationreasoning

    It cannot be completely ruled out that the cat crossed the Hungarian border and got infected there, or that mosquitos crossed the border and infected the cat at its home farm, even if it seems improbable.

    “In this case report we cannot completely rule out that the cat crossed the Hungarian border and got infected there or that mosquitos crossed the border and infected the cat at its home farm, even if it seems improbable.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    The sensitivity of echocardiography for detection of D. immitis is operator-dependent and reported between 88% and 100%.

    “The sensitivity of echocardiography for detection of D. immitis is operator-dependent and is reported between 88% and 100%.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [27] Atkins, 2008, Echocardiographic quantification of Dirofilaria immitis in experimentally infected cats, Vet. Parasitol. source

      Not checked in the free run.

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

    Premisecitation

    The largest endemic area in Europe for D. immitis is the Po River Valley in northern Italy, where prevalence in non-preventive-treated dogs ranges up to 80%.

    “The largest endemic area in Europe can be found in the Po River Valley in northern Italy, where the prevalence in non-preventive-treated dogs ranges up to 80% [2].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [2] Miguel, 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).

    Premisecitation

    Surgical removal of the adult filariae can be performed in symptomatic cats.

    “Surgical removal of the adult filariae can be performed in symptomatic cats.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [12] Mitrea, 2020, First report on clinical feline heartworm (Dirofilaria immitis) infection in Romania, Helminthologia source

      Not checked in the free run.

    • cites [15] Guidelines, C.F. (2014). Current Feline Guidelines for the Prevention, Diagnosis, and Management of Heartworm (Dirofilaria immitis) Infection in Cats, American Heartworm Society.

      Not checked in the free run.

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

    Premisecitation

    Caval syndrome is quite rare in cats, but it usually arises when one or two worms are located in the right heart causing tricuspid regurgitation.

    “Caval syndrome is quite rare in cats, but it usually arises when one or two worms are located in the right heart causing tricuspid regurgitation.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [14] Iizuka, 2009, Right Atriotomy Using Total Venous Inflow Occlusion for Removal of Heartworms in a Cat, J. Vet.-Med. Sci. source

      Not checked in the free run.

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

    Premisecitation

    It is important to remove intact worms to avoid anaphylaxis.

    “It is important to remove intact worms to avoid anaphylaxis.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [12] Mitrea, 2020, First report on clinical feline heartworm (Dirofilaria immitis) infection in Romania, Helminthologia source

      Not checked in the free run.

    • cites [15] Guidelines, C.F. (2014). Current Feline Guidelines for the Prevention, Diagnosis, and Management of Heartworm (Dirofilaria immitis) Infection in Cats, American Heartworm Society.

      Not checked in the free run.

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

    Interpretationown data

    The bronchointerstitial lung pattern at follow-up could be due to heartworm associated respiratory disease (HARD).

    “This bronchointerstitial lung pattern could be due to heartworm associated respiratory disease (HARD).”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    About 25% of cats are naturally resistant to infestation with D. immitis.

    “Moreover, about 25% of cats are naturally resistant to infestation with D. immitis [2,7].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [2] Miguel, 2012, Heartworm Disease (Dirofilaria immitis) and Their Vectors in Europe—New Distribution Trends, Front. Physiol.

      Not checked in the free run.

    • cites [7] Levy, 2017, Seroprevalence of heartworm infection, risk factors for seropositivity, and frequency of prescribing heartworm preventives for cats in the United States and Canada, J. Am. Vet.-Med. Assoc. source

      Not checked in the free run.

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

    Premisecitation

    In contrast to dogs, adulticidal therapy is not recommended because FHWD self-cures in most cases within 18-48 months.

    “In contrast to dogs, adulticidal therapy is not recommended because FHWD self-cures in most cases within 18–48 months.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [12] Mitrea, 2020, First report on clinical feline heartworm (Dirofilaria immitis) infection in Romania, Helminthologia source

      Not checked in the free run.

    • cites [15] Guidelines, C.F. (2014). Current Feline Guidelines for the Prevention, Diagnosis, and Management of Heartworm (Dirofilaria immitis) Infection in Cats, American Heartworm Society.

      Not checked in the free run.

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

    Premisecitation

    D. immitis emerges in new countries due to globalization, increased travel, import of infected dogs, climate change, and adaptability of vectors.

    “D. immitis emerges in new countries due to globalization and increased travel as well as the import of infected dogs. In addition, climate change and the adaptability of vectors play major roles in the spreading of D. immitis [4].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [4] 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).

    Premisecitation

    Prevalence of feline heartworm infections is generally considered to be five to 20% of the canine counterpart population in the affected area.

    “Prevalence of feline heartworm infections is generally considered to be five to 20% of the canine counterpart population in the affected area [7].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [7] Levy, 2017, Seroprevalence of heartworm infection, risk factors for seropositivity, and frequency of prescribing heartworm preventives for cats in the United States and Canada, J. Am. Vet.-Med. Assoc. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Microscopic detection of microfilariae and ELISA to detect circulating antigens have low sensitivity in cats.

    “Microscopic detection of microfilariae and ELISA to detect circulating antigens have low sensitivity in cats [1].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [1] Venco, 2015, Feline heartworm disease: A ‘Rubik’s-cube-like’ diagnostic and therapeutic challenge, J. Vet.-Cardiol. source

      Not checked in the free run.

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

    Premisecitation

    Severe pathological and life-threatening changes despite low parasite load of one to six adult worms per cat can be found early in cats.

    “Severe pathological and life-threatening changes despite low parasite load of one to six adult worms per cat can be found early in cats [9].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [9] Litster, 2008, Feline heartworm disease: A clinical review, J. Feline Med. Surg. source

      Not checked in the free run.

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

    Premisecitation

    Cats with outdoor access seem to have a three-fold higher risk of being antigen-positive, and male cats have been found to be more likely to develop mature infections.

    “Cats with outdoor access seem to have a three-fold higher risk of being antigen-positive and male cats have been found to be more likely to develop mature infections [8].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [8] Dillon, 2014, Effect of pre-cardiac and adult stages of Dirofilaria immitis in pulmonary disease of cats: CBC, bronchial lavage cytology, serology, radiographs, CT images, bronchial reactivity, and histopathology, Vet.-Parasitol. source

      Not checked in the free run.

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

    Premisecitation

    Sudden death in 20% of infected cats can be due to excessive inflammatory and thromboembolic response and is accompanied by haemothorax resulting from pulmonary artery dissection.

    “Sudden death in 20% of infected cats can be due to excessive inflammatory and thromboembolic response and is accompanied by haemothorax resulting from pulmonary artery dissection [10,11,12,13].”
    Quote in the paperNot a substantial claim0 of 4 sources checked
    • cites [10] Garrity, 2019, Feline asthma and heartworm disease: Clinical features, diagnostics and therapeutics, J. Feline Med. Surg. source

      Not checked in the free run.

    • cites [11] Alho, 2016, Dirofilaria immitis: A silent cause of pulmonary thromboembolism and sudden death in cats. Pathology in Practice, J. Am. Vet.-Med. Assoc. source

      Not checked in the free run.

    • cites [12] Mitrea, 2020, First report on clinical feline heartworm (Dirofilaria immitis) infection in Romania, Helminthologia source

      Not checked in the free run.

    • cites [13] Dillon, 2000, Feline heartworm disease: Correlations of clinical signs, serology, and other diagnostic results of a multicentre study, Vet. Ther.

      Not checked in the free run.

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

    Premisecitation

    Microfilariae (L1 larvae) are able to develop in only 20% of cats with mature female and male worms.

    “What is more, microfilariae (L1 larvae) are able to develop in only 20% of cats with mature female and male worms.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [2] Miguel, 2012, Heartworm Disease (Dirofilaria immitis) and Their Vectors in Europe—New Distribution Trends, Front. Physiol.

      Not checked in the free run.

    • cites [7] Levy, 2017, Seroprevalence of heartworm infection, risk factors for seropositivity, and frequency of prescribing heartworm preventives for cats in the United States and Canada, J. Am. Vet.-Med. Assoc. source

      Not checked in the free run.

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

    Premisecitation

    To diagnose FHWD, a multimodal approach is necessary, combining thoracic radiographs, serum antibody tests, echocardiography and serum antigen tests; necropsy is the gold standard for detecting adult worms.

    “To diagnose FHWD, a multimodal approach is necessary. A combination of diagnostic tools like thoracic radiographs, serum antibody tests, echocardiography and serum antigen tests are recommended. Necropsy is the gold standard for detecting adult worms [1,10,11].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [1] Venco, 2015, Feline heartworm disease: A ‘Rubik’s-cube-like’ diagnostic and therapeutic challenge, J. Vet.-Cardiol. source

      Not checked in the free run.

    • cites [10] Garrity, 2019, Feline asthma and heartworm disease: Clinical features, diagnostics and therapeutics, J. Feline Med. Surg. source

      Not checked in the free run.

    • cites [11] Alho, 2016, Dirofilaria immitis: A silent cause of pulmonary thromboembolism and sudden death in cats. Pathology in Practice, J. Am. Vet.-Med. Assoc. source

      Not checked in the free run.

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

    Premisecitation

    Compared to dogs, only a low number of L3 larvae develop to the adult stage in cats, which takes about seven to nine months.

    “Compared to dogs, only a low number of L3 larvae develop to the adult stage, which also takes about seven to nine months.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [2] Miguel, 2012, Heartworm Disease (Dirofilaria immitis) and Their Vectors in Europe—New Distribution Trends, Front. Physiol.

      Not checked in the free run.

    • cites [7] Levy, 2017, Seroprevalence of heartworm infection, risk factors for seropositivity, and frequency of prescribing heartworm preventives for cats in the United States and Canada, J. Am. Vet.-Med. Assoc. source

      Not checked in the free run.

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

    Premisecitation

    The Knott's test for detecting circulating microfilariae is less successful, but when present, the FHWD diagnosis is confirmed.

    “The Knott’s test for detecting circulating microfilariae is less successful, but when present, the FHWD diagnosis is confirmed [13].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [13] Dillon, 2000, Feline heartworm disease: Correlations of clinical signs, serology, and other diagnostic results of a multicentre study, Vet. Ther.

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Melarsomine is not safe in cats and can trigger pulmonary thromboembolism and anaphylactic reactions as a result of parasite death.

    “Melarsomine, which is used as adulticidal therapy in dogs is not safe in cats and can trigger pulmonary thromboembolism and anaphylactic reactions as result of parasite death.”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [1] Venco, 2015, Feline heartworm disease: A ‘Rubik’s-cube-like’ diagnostic and therapeutic challenge, J. Vet.-Cardiol. source

      Not checked in the free run.

    • cites [10] Garrity, 2019, Feline asthma and heartworm disease: Clinical features, diagnostics and therapeutics, J. Feline Med. Surg. source

      Not checked in the free run.

    • cites [15] Guidelines, C.F. (2014). Current Feline Guidelines for the Prevention, Diagnosis, and Management of Heartworm (Dirofilaria immitis) Infection in Cats, American Heartworm Society.

      Not checked in the free run.

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

    Premisecitation

    Right atrial and right ventricular enlargement appear quite rarely in cats and are commonly observed in dogs.

    “These findings seem to appear quite rarely in cats and are commonly observed in dogs [1].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [1] Venco, 2015, Feline heartworm disease: A ‘Rubik’s-cube-like’ diagnostic and therapeutic challenge, J. Vet.-Cardiol. source

      Not checked in the free run.

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

    Premisecitation

    Hepatorenal dysfunction is associated with poor tissue perfusion and hyporexia of these organs.

    “It is associated with poor tissue perfusion and hyporexia of these organs.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [14] Iizuka, 2009, Right Atriotomy Using Total Venous Inflow Occlusion for Removal of Heartworms in a Cat, J. Vet.-Med. Sci. source

      Not checked in the free run.

    • cites [35] Levy, 2003, Prevalence and Risk Factors for Heartworm Infection in Cats from Northern Florida, J. Am. Anim. Hosp. Assoc. source

      Not checked in the free run.

    • cites [38] Brown, W.A., and Thomas, W.P. (, January May). Surgical treatment of feline heartworm disease. Proceedings of the 16th Annual ACVIM Scientific Forum, San Diego, CA, USA.

      Not checked in the free run.

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

    Premisecitation

    When microfilariae are present, it is considered a definitive diagnosis for FHWD.

    “When microfilariae are present, it is considered a definitive diagnosis for FHWD [34].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [34] Lee, 2010, Understanding Feline Heartworm Infection: Disease, Diagnosis, and Treatment, Top. Companion Anim. Med. source

      Not checked in the free run.

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

    Premisecitation

    In a study, cats experimentally infected with 100 L3 larvae developed three to ten adult heartworms in 75% of the study population.

    “As part of a study, cats were experimentally infected with 100 L3 larvae, three to ten adult heartworms developed in 75% of the cats in this study population [1].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [1] Venco, 2015, Feline heartworm disease: A ‘Rubik’s-cube-like’ diagnostic and therapeutic challenge, J. Vet.-Cardiol. source

      Not checked in the free run.

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

    Premisecitation

    Major complications of transvenous removal range from iatrogenic damage resulting in thrombus formation, damage to endo- or myo-cardium, tricuspid valve or chordae tendinae, and pneumothorax.

    “Major complications range from iatrogenic damage that results in thrombus formation, damage to the endo- or myo-cardium, tricuspid valve or chordae tendinae as well as iatrogenic damage that cause pneumothorax [37,38].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [37] Strickland, 1998, Canine and feline caval syndrome, Clin. Tech. Small Anim. Pract. source

      Not checked in the free run.

    • cites [38] Brown, W.A., and Thomas, W.P. (, January May). Surgical treatment of feline heartworm disease. Proceedings of the 16th Annual ACVIM Scientific Forum, San Diego, CA, USA.

      Not checked in the free run.

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

    Premisecitation

    Antibodies and antigen circulate for an indeterminate length of time after the parasite has been cleared, which is a disadvantage of serological testing.

    “One disadvantage of serological testing is that antibodies and antigen circulate for an indeterminate length of time after the parasite has been cleared [35].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [35] Levy, 2003, Prevalence and Risk Factors for Heartworm Infection in Cats from Northern Florida, J. Am. Anim. Hosp. Assoc. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Usually, the worm burden is low and infections with only male or female adults reduce the sensitivity of the antigenic reaction.

    “Usually, the worm burden is low and infections with only male or female adults reduce the sensitivity of the antigenic reaction.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [1] Venco, 2015, Feline heartworm disease: A ‘Rubik’s-cube-like’ diagnostic and therapeutic challenge, J. Vet.-Cardiol. source

      Not checked in the free run.

    • cites [10] Garrity, 2019, Feline asthma and heartworm disease: Clinical features, diagnostics and therapeutics, J. Feline Med. Surg. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    These radiographic findings are common changes in cats with FHWD, although diffuse parenchymal pattern can also occur in cats with asthma or aelurostrongylosis.

    “These findings in the radiographs are also described as common changes in cats with FHWD although the diffuse parenchymal pattern can also occur in cats with asthma or aelurostrongylosis [33].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [33] Venco, 2008, Clinical evolution and radiographic findings of feline heartworm infection in asymptomatic cats, Vet. Parasitol. source

      Not checked in the free run.

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

    Premisecitation

    Hepatorenal dysfunction is reported in cats with D. immitis.

    “Hepatorenal dysfunction is also reported in cats with D. immitis.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [14] Iizuka, 2009, Right Atriotomy Using Total Venous Inflow Occlusion for Removal of Heartworms in a Cat, J. Vet.-Med. Sci. source

      Not checked in the free run.

    • cites [35] Levy, 2003, Prevalence and Risk Factors for Heartworm Infection in Cats from Northern Florida, J. Am. Anim. Hosp. Assoc. source

      Not checked in the free run.

    • cites [38] Brown, W.A., and Thomas, W.P. (, January May). Surgical treatment of feline heartworm disease. Proceedings of the 16th Annual ACVIM Scientific Forum, San Diego, CA, USA.

      Not checked in the free run.

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

    Premisecitation

    Anemia is described in cats and dogs with caval syndrome due to haemolysation.

    “Anemia is described in cats and dogs with caval syndrome due to haemolysation [37].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [37] Strickland, 1998, Canine and feline caval syndrome, Clin. Tech. Small Anim. Pract. source

      Not checked in the free run.

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

    Premisecitation

    No apparent correlation with FeLV and FIV infection was noted in a study of 2011.

    “Contrary to this study, no apparent correlation with FeLV and FIV infection was noted in a study of 2011 [8,20,34].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [8] Dillon, 2014, Effect of pre-cardiac and adult stages of Dirofilaria immitis in pulmonary disease of cats: CBC, bronchial lavage cytology, serology, radiographs, CT images, bronchial reactivity, and histopathology, Vet.-Parasitol. source

      Not checked in the free run.

    • cites [20] Farkas, 2020, The current situation of canine dirofilariosis in Hungary, Parasitol. Res. source

      Not checked in the free run.

    • cites [34] Lee, 2010, Understanding Feline Heartworm Infection: Disease, Diagnosis, and Treatment, Top. Companion Anim. Med. source

      Not checked in the free run.

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

    Premisecitation

    In necropsy of dogs with caval syndrome, tubular necrosis and haemosiderosis was found.

    “In necropsy of dogs with caval syndrome tubular necrosis and haemosiderosis was found [14,35,38].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [14] Iizuka, 2009, Right Atriotomy Using Total Venous Inflow Occlusion for Removal of Heartworms in a Cat, J. Vet.-Med. Sci. source

      Not checked in the free run.

    • cites [35] Levy, 2003, Prevalence and Risk Factors for Heartworm Infection in Cats from Northern Florida, J. Am. Anim. Hosp. Assoc. source

      Not checked in the free run.

    • cites [38] Brown, W.A., and Thomas, W.P. (, January May). Surgical treatment of feline heartworm disease. Proceedings of the 16th Annual ACVIM Scientific Forum, San Diego, CA, USA.

      Not checked in the free run.

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

    Premisecitation

    Running antigen and antibody tests can improve sensitivity compared to running one test alone.

    “Running antigen and antibody tests can improve the sensitivity compared to running one test alone [15,34].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [15] Guidelines, C.F. (2014). Current Feline Guidelines for the Prevention, Diagnosis, and Management of Heartworm (Dirofilaria immitis) Infection in Cats, American Heartworm Society.

      Not checked in the free run.

    • cites [34] Lee, 2010, Understanding Feline Heartworm Infection: Disease, Diagnosis, and Treatment, Top. Companion Anim. Med. source

      Not checked in the free run.

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

    Premisecitation

    Ivermectin and milbemycin oxime, both administered orally, as well as topical moxidectin and selamectin can all be used for the prevention of FHWD.

    “Ivermectin and milbemycin oxime, both administered orally, as well as topical moxidectin and selamectin can all be used for the prevention of FHWD [15].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [15] Guidelines, C.F. (2014). Current Feline Guidelines for the Prevention, Diagnosis, and Management of Heartworm (Dirofilaria immitis) Infection in Cats, American Heartworm Society.

      Not checked in the free run.

55 of 55

  • The paper relies on this without support.

    There are no prior reports of feline heartworm disease in Austria.

    “To our knowledge, there are no reports of FHWD in Austria.”
    “This case report represents the first report of autochthonous D. immitis infection in Austria.”

  • The authors state this as an assumption.

    Feline heartworm disease is the most likely diagnosis in this case due to clinical presentation and echocardiographic findings.

    “In our case report we assume that FHWD is the most likely diagnosis due to clinical presentation and findings in echocardiography.”

  • The paper relies on this without support.

    No publications exist regarding A. chabaudi being detectable in echocardiography.

    “Currently no publications exist regarding A. chabaudi being detectable in echocardiography.”

  • The paper relies on this without support.

    No publications exist regarding A. abstrusus and T. brevior being detectable in echocardiography.

    “To our knowledge, no publications exist regarding A. abstrusus and T. brevior being detectable in echocardiography, what makes these differentials unlikely.”

  • The paper relies on this without support.

    In Austria, Aedes vexans and the Culex pipiens complex are potential vectors for Dirofilaria parasites.

    “In Austria two mosquito species, Aedes vexans and the Culex pipiens complex are already known to act as potential vectors for Dirofilaria parasites.”

  • The paper relies on this without support.

    The cat's D. immitis infection was autochthonous (acquired in Austria, not imported or travel-associated).

    “This case report shows the first cat in Austria with an autochthonous D. immitis infection.”
    “This case report describes what is potentially the first documented autochthonous D. immitis infection in Austria.”

  • The paper relies on this without support.

    No previous autochthonous D. immitis infections in cats in Austria have been documented.

    “This case report shows the first cat in Austria with an autochthonous D. immitis infection.”
    “This case report describes what is potentially the first documented autochthonous D. immitis infection in Austria.”

  • The paper relies on this without support.

    Cats are not the natural reservoir of D. immitis.

    “Furthermore, considering that the cat is not the natural reservoir of the parasite, it must be deduced that in the same area there were dogs infected by D. immitis and not diagnosed.”

  • The paper relies on this without support.

    The prognosis for caval syndrome is poor in most cases.

    “In most cases, the prognosis for caval syndrome is poor, so surgical removal seemed the only realistic chance for this cat.”
9 of 9

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?

  • Some studies have reported D. immitis in cats in traditionally endemic countries such as Spain, Portugal, Italy, and Greece, while first reports of feline heartworm have been published in some new endemic countries (Germany and Austria).

    “Some studies have reported D. immitis in cats in traditionally endemic countries, such as Spain, Portugal, Italy, and Greece, while the first reports of feline heartworm have been published in some new endemic countries as well (Germany and Austria).”

    From What has happened to heartworm disease in Europe in the last 10 years? (2022) · cites this paper as [130]

  • In Germany, a retrospective study from 2012 to 2020 identified heartworm in three cats in 2012, and in Austria the first case of autochthonous feline D. immitis infection was published in 2012.

    “In Germany, a retrospective study from 2012 to 2020 identified heartworm in three cats in 2012 [129]. In Austria, the first case of autochthonous feline D. immitis infection is published in 2012 [130].”

    From What has happened to heartworm disease in Europe in the last 10 years? (2022) · cites this paper as [130]

  • The first autochthonous case of D. immitis was recently documented in a cat from Burgenland.

    “Moreover, the first autochthonous case of D. immitis was recently documented in a cat from Burgenland”

    From Dirofilaria spp. and Angiostrongylus vasorum: current risk of spreading in Central and Northern Europe. (2021) · cites this paper as [66]

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 target length is reported as both 202 and 203 bp

    Minor

    The methods identify the shorter PCR target as 203 bp, but the discussion calls it a 202 bp sequence.

  • Follow-up timing differs between the abstract and case report

    Minor

    The abstract places the control examination one year after surgery; the case report places it 16 months after surgery.

  • Claim of no sonographic abnormalities conflicts with follow-up echocardiogram

    Minor

    The discussion says there were no detectable sonographic abnormalities at 16 months, but the follow-up echocardiogram reports tricuspid and mitral insufficiency and probable mild pulmonary hypertension.

3 of 3

Cites

Flagged first, then by citations

1 of the 43 references couldn’t be matched to a known paper.

Research works printed but not linked: 1

  1. Brown, W.A., and Thomas, W.P. (, January May). Surgical treatment of feline heartworm disease. Proceedings of the 16th Annual ACVIM Scientific Forum, San Diego, CA, USA.

Cited by

Sorted by citations

Related

Authors
Kulmer, L.-M., Unterköfler, M. S., Fuehrer, H.-P., Janovska, V., Pagac, M., Svoboda, M., Venco, L., & Leschnik, M.
Affiliations
  • University of Veterinary Medicine Vienna (AT)
  • Veterinary Hospital Parndorf, 7111 Burgenland, Austria
  • Veterinary Hospital Città di Pavia, 27100 Pavia, Italy
Corresponding author
Kulmer, Lisa-Maria
ORCID
Venue
Pathogens
Publisher
MDPI AG
Published
2021-08-30
Volume
10
Issue
9
Pages
1104
ISSN
2076-0817 (ISSN-L)
DOI
10.3390/pathogens10091104
PMC
PMC8466588
OpenAlex
W3197114928
Semantic Scholar
a87f2c7ddee2f2c28b681ac52f200028bee712dc
Cited by
21
References
43
Citations by year
2025: 3 · 2024: 1 · 2023: 1 · 2022: 15 · 2021: 1
FWCI
1.43
Type
journal article
Language
en
Open access
Licence
Locations
  • Pathogens (publishedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, other-oa)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Institutional Research Information System University of Turin (University of Turin) (submittedVersion, cc-by)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Topics
  • Health Sciences › Medicine › Infectious Diseases › Parasitic Diseases Research and Treatment
  • Health Sciences › Veterinary › Small Animals › Helminth infection and control
  • Health Sciences › Medicine › Public Health, Environmental and Occupational Health › Research on Leishmaniasis Studies
Keywords
Dirofilaria immitis, feline heartworm disease, autochthonous infection, cats, caval syndrome, acute kidney injury

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-09.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-09.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review