CoChat
Sign Up
Cited by 34Parasitic Diseases Research and TreatmentHelminth infection and controlResearch on Leishmaniasis Studies

Prevalence of heartworm in dogs and cats of Madrid, Spain

Open access
Montoya-Alonso, José Alberto, Morchón, Rodrigo, Falcón-Cordón, Yaiza, Falcón-Cordón, Soraya, Simón, Fernando, Carretón, Elena·2017·Parasites & Vectors
DOI 10.1186/s13071-017-2299-xPMC PMC5530495
Open this paper in CoChat — free accountOpen PDF

Abstract

BACKGROUND: Dirofilaria immitis causes heartworm disease, a chronic and potentially fatal cardiopulmonary disease which mainly affects dogs and cats. It is present in most of Spain, due to favourable climatic factors. Madrid, located in the centre of the Iberian Peninsula, is the most highly populated city in the country. There is a lack of current data on canine heartworm and there are no published epidemiological data regarding feline heartworm in this region, therefore the aim of this study was to assess the prevalence and current distribution of canine and feline dirofilariosis in the province of Madrid. METHODS: Serum samples from 1716 dogs and 531 cats, from animals living in the metropolitan area of Madrid and adjacent areas, were studied. All the samples, either from cats and dogs, were tested for circulating D. immitis antigens using a commercial immunochromatographic test kit. Furthermore, to establish the seroprevalence of heartworm infection in cats, serological techniques for anti-D. immitis and anti-Wolbachia antibody detection were used. RESULTS: Prevalence of D. immitis in the canine population of Madrid was 3%, showing an increase in comparison to previous data. The presence of heartworm in the city centre could be influenced by the presence of Urban Heat Islands, while the positive dogs from metropolitan and adjacent areas were mainly located under the influence of rivers. Regarding cats, 0.2% were positive to the antigens test and 7.3% were seropositive to both anti-D. immitis and Wolbachia surface protein antibodies, which demonstrate the presence of feline heartworm in Madrid. Seropositive cats were present in the same areas where positive dogs were found. Indoor/outdoor cats showed the highest seroprevalence whereas the lowest corresponded to indoor cats, demonstrating that prophylactic treatments should be carried out regardless of lifestyle. Infection was found in 2.2% of dogs and 6.7% of the cats < 1 year-old, which indicates that early preventive campaigns in puppies and kittens should be implemented. CONCLUSIONS: The results point to the need for adequate prophylactic measures through the administration of macrocyclic lactones in animals living in Madrid. Veterinarians should be aware of the presence of this disease and include heartworm in the differential diagnosis when a pet presents with symptoms compatible with D. immitis.

AI snapshot

Written from the paper’s full text.

TL;DR

This study assessed Dirofilaria immitis prevalence in 1716 dogs and 531 cats from Madrid and adjacent areas, reporting canine antigen prevalence of 3% and feline antigen positivity of 0.2% with 7.3% seropositivity. The authors conclude that canine and feline heartworm are present in Madrid, with canine prevalence increased compared with earlier data, supporting prophylactic treatment.

Key findings

  • Canine D. immitis antigen prevalence was 3% (52/1716); it was 3.3% in the city of Madrid and 2.7% in metropolitan/adjacent areas. Highest municipal prevalences were Aranjuez 10.0%, Majadahonda 6.4%, and Alcalá de Henares 5.9%.
  • Cats had 0.2% (1/531) antigen positivity and 7.3% (39/531) seropositivity to both anti-D. immitis and anti-Wolbachia surface protein antibodies; seroprevalence was 6.1% in Madrid city and 9.1% in metropolitan/adjacent areas, with highest municipal seroprevalences in Alcalá de Henares (27.3%), Aranjuez (20.8%), and Majadahonda (11.1%).
  • Indoor/outdoor cats had the highest seroprevalence (11.4%), followed by outdoor cats (10.4%), while indoor cats had the lowest (4.6%) (P = 0.017). Infection was found in 2.2% of dogs and 6.7% of cats < 1 year old.
  • No significant differences were found by sex in dogs or cats, or by breed in dogs or cats; the highest canine prevalences were in dogs aged 1–6 years.

Methods

  • Cross-sectional study of serum samples from 1716 dogs and 531 cats presented to 20 veterinary centres in the metropolitan area of Madrid and adjacent areas, covering 98 municipalities and 218 postal codes between March 2015 and September 2016. Inclusion criteria were age > 6 months, no travel outside the study area, no prior heartworm treatment, and no previous heartworm infection history.
  • All dog and cat samples were tested for circulating D. immitis antigens using a commercial immunochromatographic test kit (Uranotest Dirofilaria®). Cats were also tested by ELISA for anti-D. immitis and anti-Wolbachia surface protein antibodies, and were considered seropositive when both antibody types were present jointly.
  • Data were analysed descriptively with proportions and χ² tests using SPSS Base 20.0; significance was set at P < 0.05.

Limitations

  • The paper does not include a formal limitations section. It states that antigen testing in cats has relatively low sensitivity and detects only adult female worms, so a negative result does not rule out infection with male worms, pre-adult worms, or a single female adult worm; antibody tests can remain positive after parasite death and do not differentiate current from past infection.
  • Evident from the text: sampling was from veterinary clinics and may not represent the broader pet population; several subgroup comparisons were not statistically significant, limiting inference from those findings; and prevalence/seroprevalence estimates depend on the diagnostic tests used.

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

Integrity signals

Registry

Crossref · 10.1186/s13071-017-2299-x

Cites

Statistics

Nothing to recompute.

Claims the paper makes

0 of 34 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    2.2% of dogs less than 1 year old were infected with D. immitis.

    “Infection was found in 2.2% of dogs and 6.7% of the cats < 1 year-old, which indicates that early preventive campaigns in puppies and kittens should be implemented.”
    • Also stated in: § Methods · plain
      “| < 1 year | 45 | 2.2 | 15 | 6.7 |”
    Quote in the paperSubstantial claim
  • Findingown data

    The prevalence of heartworm infection in the canine population of the city of Madrid was 3.3%.

    “The prevalence of heartworm infection in the city of Madrid in the canine population was 3.3%.”
    • Also stated in: § Discussion · plain
      “In the present study, the prevalence observed in the city centre was 3.3%.”
    Quote in the paperSubstantial claim
  • Findingown data

    There were no significant differences in D. immitis prevalence between male and female dogs.

    “There were not significant differences in the prevalences between males (3.2%) and females (2.9%) (χ 2 = 0.006, df = 1, P = 0.939).”
    Quote in the paperNot a substantial claim
  • Findingown data

    Feline seropositivity in the city of Madrid was 6.1%.

    “When the cats were analysed, the seropositivity in the city of Madrid was 6.1%.”
    Quote in the paperNot a substantial claim
  • Findingown data

    The canine prevalence in the metropolitan and adjacent areas was 2.7% (2.4% in females and 3% in males).

    “The prevalence in the metropolitan and adjacent areas was 2.7% (2.4% in females and 3% in males); the distribution was not uniform, the positive dogs being mainly located in the area of influence of the major rivers.”
    Quote in the paperNot a substantial claim
  • May combine two claims. 12
  • Classified as probably not a substantial claim. 3

  • May combine two claims.

    Findingown data

    The distribution of positive dogs in the metropolitan and adjacent areas was not uniform, and positive dogs were mainly located in areas under the influence of major rivers, including the Tajo, Jarama, Henares and Guadarrama.

    “The presence of heartworm in the city centre could be influenced by the presence of Urban Heat Islands, while the positive dogs from metropolitan and adjacent areas were mainly located under the influence of rivers.”
    • Also stated in: § Results · plain
      “The prevalence in the metropolitan and adjacent areas was 2.7% (2.4% in females and 3% in males); the distribution was not uniform, the positive dogs being mainly located in the area of influence of the major rivers.”
    • Also stated in: § Discussion · plain
      “The results from the study show how currently positive dogs outside the city centre are mainly concentrated in areas under the influence of the rivers Tajo, Jarama, Henares and Guadarrama.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The highest feline seroprevalences by municipality were in Alcalá de Henares (27.3%), Aranjuez (20.8%) and Majadahonda (11.1%), all under the influence of river basins.

    “By municipalities, the highest seroprevelances were observed in Alcalá de Henares (27.3%), Aranjuez (20.8%) and Majadahonda (11.1%), all of them under the influence of river basins.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The highest canine prevalences by municipality were in Aranjuez (10.0%), Majadahonda (6.4%) and Alcalá de Henares (5.9%), all influenced by rivers.

    “By municipalities, the highest prevalences were observed in Aranjuez (10.0%), Majadahonda (6.4%) and Alcalá de Henares (5.9%), all of them influenced by rivers (Fig. 1).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The highest feline seroprevalence was found in cats between 6 and 9 years old, with no significant differences between age groups.

    “By age ranges, the highest seroprevalence was found in cats between 6 and 9 year-old; no significant differences were found between all groups of age (χ 2 = 7.265, df = 5, P = 0.202) (Table 1).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    European shorthair cats had a seroprevalence of 7.5% while the mean seroprevalence in other breeds was 7.1%, with no significant difference.

    “By breed, the European shorthair presented a seroprevalence of 7.5% while the mean seroprevalence in the other breeds was 7.1% (χ 2 = 0.036, df = 1, P = 0.850).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Indoor/outdoor cats showed the highest seroprevalence (11.4%), followed by outdoor cats (10.4%), while indoor cats had the lowest (4.6%).

    “Indoor/outdoor cats showed the highest seroprevalence whereas the lowest corresponded to indoor cats, demonstrating that prophylactic treatments should be carried out regardless of lifestyle.”
    • Also stated in: § Results · plain
      “Indoor/outdoor cats showed the highest seroprevalence (11.4%), followed by outdoor cats (10.4%) while the lowest corresponded to indoor cats (4.6%) (χ 2 = 8.201, df = 2, P = 0.017).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The highest canine D. immitis prevalences were found in dogs from 1 to 6 years old, with the highest in dogs 1-3 years followed by 3-6 years.

    “By age ranges, the highest prevalences were found in dogs from 1 to 6 years, and significant differences were only observed between dogs betwee 9–12 year-old compared with dogs between 1 and 6 year-old (χ 2 = 2.753, df = 5, P = 0.738) (Table 1).”
    • Also stated in: § Discussion · plain
      “By age, the highest prevalence was found in dogs from 1 to 3 years followed by dogs from 3 to 6 years; other studies showed the highest prevalences in older dogs [14, 23].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [14] Montoya-Alonso JA, Carretón E, Corbera JA, Juste MC, Mellado I, Morchón R, et al. Current prevalence of Dirofilaria immitis in dogs, cats and humans from the island of Gran Canaria. Spain: Vet Parasitol; 2011;176(4):291–4. source

      Not checked in the free run.

    • cites [23] Simón L, Afonin A, López-Díez LI, González-Miguel J, Morchón R, Carretón E, et al. Geo-environmental model for the prediction of potential transmission risk of Dirofilaria in an area with dry climate and extensive irrigated crops. The case of Spain. Vet Parasitol. 2014;200(3-4):257–64. source

      Not checked in the free run.

  • May combine two claims.

    Findingown data

    Mongrel dogs showed higher but not significantly different D. immitis prevalences (4.2%) compared with pure-breed dogs (2.6%).

    “By breed, mongrel dogs showed higher but not significantly different prevalences (4.2%) when compared with pure-breed dogs (2.6%) (χ 2 = 2.902, df = 1, P = 0.088).”
    • Also stated in: § Discussion · plain
      “Although not statistically significant, mongrel dogs showed higher prevalences when compared with pure-breed dogs, as reported in other studies [21].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [21] Montoya-Alonso JA, Carretón E, Simón L, González-Miguel J, García-Guasch L, Morchón R, Simón F. Prevalence of Dirofilaria immitis in dogs from Barcelona: validation of a geospatial prediction model. Vet Parasitol. 2015;212(3–4):456–9. source

      Not checked in the free run.

  • May combine two claims.

    Findingown data

    In the city of Madrid, feline seroprevalence was 7.6% in females and 4.3% in males.

    “By sex, the seroprevalence was 7.6% in females and 4.3% in males.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingreasoning

    Seropositive cats were present in the same areas where positive dogs were found, influenced by the same climatic conditions.

    “Seropositive cats were present in the same areas where positive dogs were found, influenced by the same climatic conditions.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Antibody tests detect antibodies produced by the host in response to infection, can remain positive for a long time after the death of the parasite, and do not differentiate a current from a past infection.

    “On the other hand, antibody tests detect antibodies produced by the host in response to infection, which therefore can remain positive for a long time after the death of the parasite and do not differentiate a current or a past infection [24, 26].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [24] Lee AC, Atkins CE. Understanding feline heartworm infection: disease, diagnosis, and treatment. Top Companion Anim Med. 2010;25(4):224–30. source

      Not checked in the free run.

    • cites [26] Venco L, Marchesotti F, Manzocchi S. Feline heartworm disease: A ’Rubik’s-cube-like’ diagnostic and therapeutic challenge. J Vet Cardiol. 2015;17(Suppl 1):S190–201. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The sensitivity of antigen testing is relatively low in cats, and these tests only detect adult and female worms.

    “This may be due to the fact that the sensitivity of antigen testing is relatively low in cats, and because these only detect adult and female worms.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [24] Lee AC, Atkins CE. Understanding feline heartworm infection: disease, diagnosis, and treatment. Top Companion Anim Med. 2010;25(4):224–30. source

      Not checked in the free run.

    • cites [25] Berdoulay P, Levy JK, Snyder PS, Pegelow MJ, Hooks JL, Tavares LM, et al. Comparison of serological tests for the detection of natural heartworm infection in cats. J Am Anim Hosp Assoc. 2004;40(5):376–84. source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Interpretationcitation

    Dogs living in urban areas are not safe from heartworm infection.

    “Dogs living in urban areas are not safe from heartworm infection and should receive adequate prophylaxis with macrocyclic lactones, as concluded in a similar study in Barcelona [21].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [21] Montoya-Alonso JA, Carretón E, Simón L, González-Miguel J, García-Guasch L, Morchón R, Simón F. Prevalence of Dirofilaria immitis in dogs from Barcelona: validation of a geospatial prediction model. Vet Parasitol. 2015;212(3–4):456–9. source

      Not checked in the free run.

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

    Premisecitation

    Other studies showed the highest canine heartworm prevalences in older dogs.

    “other studies showed the highest prevalences in older dogs [14, 23].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [14] Montoya-Alonso JA, Carretón E, Corbera JA, Juste MC, Mellado I, Morchón R, et al. Current prevalence of Dirofilaria immitis in dogs, cats and humans from the island of Gran Canaria. Spain: Vet Parasitol; 2011;176(4):291–4. source

      Not checked in the free run.

    • cites [23] Simón L, Afonin A, López-Díez LI, González-Miguel J, Morchón R, Carretón E, et al. Geo-environmental model for the prediction of potential transmission risk of Dirofilaria in an area with dry climate and extensive irrigated crops. The case of Spain. Vet Parasitol. 2014;200(3-4):257–64. source

      Not checked in the free run.

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

    Interpretationreasoning

    The higher feline seroprevalence in metropolitan and adjacent areas may be because cats living in those municipalities spend time outdoors more frequently.

    “The seroprevalence is higher in cats from metropolitan and adjacent areas when compared with the city centre; probably one of the reasons may be because cats living in those municipalities spend time outdoors more frequently.”
    Quote in the paperNot a substantial claim
15 of 15

  • The paper relies on this without support.

    Cats do not usually receive chemoprophylaxis, so the risk of heartworm infection is higher in cats than in dogs.

    “Cats do not usually receive chemoprophylaxis and therefore the risk of infection is higher in this species than in dogs.”

  • The paper relies on this without support.

    There are no epidemiological data published regarding feline heartworm in Madrid.

    “There are no epidemiological data published regarding cats.”

  • The paper relies on this without support.

    There is a lack of current epidemiological data on animal heartworm focusing on the province of Madrid.

    “There is a lack of current epidemiological data of animal heartworm focusing on the province of Madrid.”

  • The paper relies on this without support.

    The animals sampled at veterinary clinics are representative of the canine and feline population of the studied area.

    “The present study included 1716 dogs and 531 cats presented to veterinary clinics between March 2015 and September 2016.”

  • The paper relies on this without support.

    The commercial immunochromatographic test kit accurately detects circulating D. immitis antigens in dogs and cats.

    “All the samples, either from cats and dogs, were tested for circulating D. immitis antigens using a commercial immunochromatographic test kit (Uranotest Dirofilaria®, Urano Vet SL, Barcelona, Spain) according to the manufacturer’s instructions.”
5 of 5

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?

  • Dogs living indoors showed significantly lower prevalences because they are less exposed to vector mosquitoes.

    “Regarding habitat, dogs living indoors showed significantly lower prevalences, as shown in other similar studies [8,9,11,12,13,19]. As has been pointed out in previous studies, animals that live indoors are less exposed to the presence of vector mosquitoes and, thus, prevalences are lower.”

    From Expansion of canine heartworm in Spain (2022) · cites this paper as [13]

  • In the last 15 years, a slight increase in heartworm can be confirmed in most autonomous communities, with decreasing prevalences or similar values only in Aragon, Catalonia, Valencian Community, Madrid and Castilla y León.

    “in the last 15 years a slight increase in heartworm can be confirmed in most of the autonomous communities, with decreasing prevalences or with similar values only in Aragon, Catalonia, Valencian Community, Madrid and Castilla y León.”

    From Expansion of canine heartworm in Spain (2022) · cites this paper as [13]

  • In Madrid, canine heartworm prevalence was 3%, and in the province of Salamanca, overall prevalence was 7.3%, with higher prevalence in zones with irrigated crops.

    “The canine population in Madrid presented a prevalence of 3%, [22] and in the province of Salamanca, the overall percentage was 7.3% [20], although in zones with irrigated crops, the prevalence was higher.”

    From What has happened to heartworm disease in Europe in the last 10 years? (2022) · cites this paper as [22]

  • In Spain, feline heartworm seroprevalence and prevalence were 24.4% and 3.6% in Zaragoza, 7.3% and 0.2% in Madrid, and 11.47% and 0.26% in Barcelona, respectively.

    “It is the case of Zaragoza, where the seroprevalence reported was 24.4% and the prevalence was 3.6% [118]. In Madrid, seroprevalence and prevalence were 7.3 and 0.2%, respectively [22]. In Barcelona, 11.47% of the cats were seropositive and 0.26% were positive for D. immitis antigens [3].”

    From What has happened to heartworm disease in Europe in the last 10 years? (2022) · cites this paper as [22]

  • Buildings and asphalt retain heat, leading to heat islands, which favour microclimates that support development of D. immitis larvae in mosquitoes even during colder months.

    “Buildings and asphalt retain the heat of the day, leading to the formation of so-called “heat islands”, which favour the creation of microclimates that support the development of D. immitis larvae in mosquitoes even during the colder months [22].”

    From What has happened to heartworm disease in Europe in the last 10 years? (2022) · cites this paper as [22]

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.

  • Canine age comparison is called significant despite P = 0.738

    Major

    The paper says the age-group difference was significant, but its reported P value is above the paper's stated significance threshold of 0.05.

  • Indoor cats are described as having higher seroprevalence despite having the lowest

    Minor

    The discussion describes indoor cats as having higher seroprevalence, whereas the results explicitly identify indoor cats as the group with the lowest seroprevalence.

2 of 2

The citation lists haven’t been fetched yet

References 25 · Cited by 34

Research works printed but not linked: 2

  1. Rojo-Vázquez FA, Valcárcel F, Guerrero J, Gómez M. Prevalencia de la dirofilariosis canina en cuatro áreas geográficas de España. Med Vet. 1990;7(5):297–305.
  2. Sobrino JA, Sòria G, Oltra-carrió R, Jiménez-Muñoz JC, Romaguera M, Cuenca J, et al. DESIREX 2008: urban Heat Island analysis in the City of Madrid. Revista de Teledetección. 2009;31:80–92.

Authors
Montoya-Alonso, J. A., Morchón, R., Falcón-Cordón, Y., Falcón-Cordón, S., Simón, F., & Carretón, E.
Affiliations
  • Universidad de Las Palmas de Gran Canaria (ES)
  • Universidad de Salamanca (ES)
Corresponding author
Carretón, Elena
ORCID
Venue
Parasites & Vectors
Publisher
Springer Science and Business Media LLC
Published
2017-07-26
Volume
10
Issue
1
Pages
354-354
ISSN
1756-3305 (ISSN-L)
DOI
10.1186/s13071-017-2299-x
PMC
PMC5530495
OpenAlex
W2737138583
Semantic Scholar
ed07487776e9b360e4ff862c1f6bb31c94c08e7c
Cited by
34
References
25
Citations by year
2026: 2 · 2025: 2 · 2024: 4 · 2023: 4 · 2022: 7 · 2021: 6 · 2020: 4 · 2019: 4 · 2018: 1
FWCI
1.89
Type
journal article
Language
en
Open access
Licence
cc-by
Locations
  • Parasites & Vectors (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Hispana (publishedVersion, cc-by-nc-nd)
  • Acceda (Universidad de Las Palmas de Gran Canaria) (submittedVersion)
  • LA Referencia (Red Federada de Repositorios Institucionales de Publicaciones Científicas) (submittedVersion, cc-by-nc-nd)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion)
  • Gredos (University of Salamanca) (submittedVersion, cc-by-nc-nd)
  • Hispana (submittedVersion, cc-by-nc-nd)
Funders
Bayer Hispania S.A. (Not applicable)
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
canine heartworm disease, feline heartworm disease, Dirofilaria immitis, seroprevalence, urban heat island, Madrid
MeSH terms
Animals, Antigens, Helminth, Cat Diseases, Cats, Cities, Dirofilaria immitis, Dirofilariasis, Dog Diseases, Dogs, Female, Male, Spain, Prevalence, Seroepidemiologic Studies

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