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Cited by 18Helminth infection and controlVector-borne infectious diseasesParasitic infections in humans and animals

Preliminary Study on the Prevalence of Endoparasite Infections and Vector-borne Diseases in Outdoor Dogs in Bulgaria

Open access
Iliev, P. T., Kirkova, Z. T., Tonev, A. S.·2020·Helminthologia
DOI 10.2478/helm-2020-0016PMC PMC7261023
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Abstract

Summary: The present work was designed to evaluate the prevalence of gastrointestinal parasites and some vector-borne pathogens in dogs in Bulgaria. A total of 172 owned dogs, keeping outside, were included in the study. Fecal samples were examined using standard flotation and sedimentation methods. Blood samples were processed by Knott’s technique, SNAP™ 4Dx Plus Test (IDEXX) and Angio Detect™ Test (IDEXX). The overall prevalence of gastrointestinal parasites was 64.5%. Eggs of hookworms ( Ancylostoma sp. and Uncinaria sp.) were the most frequently detected (54.1%), followed by Trichuris vulpis (15.1%), Capillaria sp. (11.0%), Toxocara canis (6.4%), Cystoisospora sp. (4.1%), Sarcocystis sp. (2.3%), Toxascaris leonina (1.7%), Taenia sp. (1.2%) and Linguatula serrata (0.6%). In addition, hookworms were the most commonly involved in the cases of single infection (20.3%). Combinations between Capillaria sp./hookworms and T. vulpis /hookworms were the most common co-infections (4.1% and 2.9%, respectively). Blood samples revealed the presence of antibodies against Ehrlichia sp. (13.4%), Anaplasma sp. (13.4%) and Borrelia burgdorferi (1.7%). Antigens of Dirofilaria immitis and Angiostrongylus vasorum were detected in 10.5% and 0.6% of the samples tested, respectively. Microfilariae of Dirofilaria repens were found in 5.8% of the blood samples. Additionally, the prevalence of D. immitis and Ehrlichia sp. was significantly higher in adult than in young dogs (p<0.05). In contrast, the gender was not considered as a risk factor contributing to the occurrence of infections.

AI snapshot

Written from the paper’s full text.

TL;DR

This preliminary study of 172 outdoor owned dogs in Bulgaria found a high overall prevalence of gastrointestinal parasites (64.5%) and frequent evidence of vector-borne pathogens. Age was significantly associated with *D. immitis* and *Ehrlichia* sp. infections, while gender was not a risk factor.

Key findings

  • Overall gastrointestinal parasite prevalence was 64.5%; hookworms (*Ancylostoma*/*Uncinaria* spp.) were most frequent at 54.1%, followed by *Trichuris vulpis* (15.1%), *Capillaria* sp. (11.0%), *Toxocara canis* (6.4%), *Cystoisospora* sp. (4.1%), *Sarcocystis* sp. (2.3%), *Toxascaris leonina* (1.7%), *Taenia* sp. (1.2%), and *Linguatula serrata* (0.6%).
  • Blood testing detected antibodies against *Ehrlichia* sp. (13.4%), *Anaplasma* sp. (13.4%), and *Borrelia burgdorferi* (1.7%); antigens of *Dirofilaria immitis* and *Angiostrongylus vasorum* were found in 10.5% and 0.6%, respectively, and *D. repens* microfilariae in 5.8%.
  • Single infections occurred in 38.4% of dogs; the most common co-infections were *Capillaria* sp./hookworms (4.1%) and *T. vulpis*/hookworms (2.9%).
  • Prevalence of *D. immitis* and *Ehrlichia* sp. was significantly higher in adult than young dogs (p<0.05); gender was not associated with infection prevalence.

Methods

  • Cross-sectional study conducted July 2016–September 2017 on 172 owned dogs (115 males, 57 females) aged 1 month to 12 years, reared outdoors and recruited from outskirts of Rousse, Razgrad, Sofia, Stara Zagora, and Plovdiv, Bulgaria.
  • Fecal samples were examined by direct smear, flotation with saturated sodium chloride, and sedimentation; blood samples were processed by Knott’s technique, SNAP™ 4Dx Plus Test (IDEXX), and Angio Detect™ Test (IDEXX).
  • Prevalence and 95% confidence intervals were calculated; differences by gender and age were assessed with Chi-square tests using MedCalc, with significance at P ≤ 0.05.

Limitations

  • The paper does not include a dedicated limitations section; no limitations are explicitly stated.
  • Evident from the text: this is described as a preliminary study with a relatively small sample of owned outdoor dogs from selected Bulgarian regions, so findings may not be representative of all dogs in Bulgaria.
  • Evident from the text: the author notes that *Capillaria* sp. prevalence may be underestimated because eggs can pass through the alimentary tract after ingestion of contaminated food or coprophagy, not only from adult lungworms.

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

Integrity signals

Registry

Crossref · 10.2478/helm-2020-0016

Cites

Statistics

Nothing to recompute.

Claims the paper makes

0 of 2 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    The overall prevalence of gastrointestinal parasites in outdoor dogs in Bulgaria was 64.5%.

    “The overall prevalence of gastrointestinal parasites was 64.5%.”
    • Also stated in: § Results · plain
      “The overall prevalence of GI parasites was 64.5 %.”
    • Also stated in: § Discussion · plain
      “The findings of this study showed that more than half of the dogs (64.5 %) were infected by at least one species of GI parasite.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The 172 owned outdoor dogs sampled from the specified regions are representative of outdoor dogs in Bulgaria.
    • Rests on an assumption: The diagnostic methods used (flotation, sedimentation, Knott’s technique, SNAP 4Dx Plus Test, and Angio Detect Test) have sufficient sensitivity and specificity to estimate the prevalence of the targeted pathogens.
  • Findingown data

    The prevalence of Ehrlichia sp. was significantly higher in adult than in young dogs (p<0.05).

    “Additionally, the prevalence of D. immitis and Ehrlichia sp. was significantly higher in adult than in young dogs (p<0.05).”
    • Also stated in: § Results · plain
      “Similarly, antibodies against Ehrlichia sp. were more commonly detected in the adult animals (χ2=3.740).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The 172 owned outdoor dogs sampled from the specified regions are representative of outdoor dogs in Bulgaria.
    • Rests on an assumption: The diagnostic methods used (flotation, sedimentation, Knott’s technique, SNAP 4Dx Plus Test, and Angio Detect Test) have sufficient sensitivity and specificity to estimate the prevalence of the targeted pathogens.
    • Rests on an assumption: Seropositivity for Ehrlichia sp., Anaplasma sp., and Borrelia burgdorferi indicates infection with these pathogens.
  • Findingown data

    Antibodies against Ehrlichia sp. were present in 13.4% of dogs.

    “Blood samples revealed the presence of antibodies against Ehrlichia sp. (13.4%), Anaplasma sp. (13.4%) and Borrelia burgdorferi (1.7%).”
    • Also stated in: § Results · plain
      “The serum analysis identified antigens of D. immitis and A. vasorum (10.5 % and 0.6 % of the samples, respectively) and antibodies against Anaplasma sp. (13.4 %), Ehrlichia sp. (13.4 %) and B. burgdorferi (1.7 %).”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The 172 owned outdoor dogs sampled from the specified regions are representative of outdoor dogs in Bulgaria.
    • Rests on an assumption: The diagnostic methods used (flotation, sedimentation, Knott’s technique, SNAP 4Dx Plus Test, and Angio Detect Test) have sufficient sensitivity and specificity to estimate the prevalence of the targeted pathogens.
    • Rests on an assumption: Seropositivity for Ehrlichia sp., Anaplasma sp., and Borrelia burgdorferi indicates infection with these pathogens.
  • Findingown data

    Cases of single infection were found in 38.4% of dogs sampled.

    “Cases of single infection were found in 38.4 % of dogs sampled (Table 2).”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The 172 owned outdoor dogs sampled from the specified regions are representative of outdoor dogs in Bulgaria.
    • Rests on an assumption: The diagnostic methods used (flotation, sedimentation, Knott’s technique, SNAP 4Dx Plus Test, and Angio Detect Test) have sufficient sensitivity and specificity to estimate the prevalence of the targeted pathogens.
  • Findingown data

    T. vulpis/hookworms co-infection prevalence was 2.9%.

    “The most frequently detected co-infections were with Capillaria sp./hookworms (4.1 %) and T. vulpis/hookworms (2.9 %).”
    • Also stated in: § Abstract · plain
      “Combinations between Capillaria sp./hookworms and T. vulpis/hookworms were the most common co-infections (4.1% and 2.9%, respectively).”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The 172 owned outdoor dogs sampled from the specified regions are representative of outdoor dogs in Bulgaria.
    • Rests on an assumption: The diagnostic methods used (flotation, sedimentation, Knott’s technique, SNAP 4Dx Plus Test, and Angio Detect Test) have sufficient sensitivity and specificity to estimate the prevalence of the targeted pathogens.
  • May combine two claims. 2
  • Classified as probably not a substantial claim. 2

  • May combine two claims.

    Interpretationreasoning

    The findings suggest environmental contamination with infective stages of parasites and the presence of arthropods carrying different pathogens.

    “Our findings demonstrate a wide variety of endoparasites and high prevalence rates of parasitism, suggesting environmental contamination with infective stages of parasites and presence of arthropods carrying different pathogens.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The 172 owned outdoor dogs sampled from the specified regions are representative of outdoor dogs in Bulgaria.
    • Rests on an assumption: The diagnostic methods used (flotation, sedimentation, Knott’s technique, SNAP 4Dx Plus Test, and Angio Detect Test) have sufficient sensitivity and specificity to estimate the prevalence of the targeted pathogens.
    • Rests on an assumption: Seropositivity for Ehrlichia sp., Anaplasma sp., and Borrelia burgdorferi indicates infection with these pathogens.

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

    Study design and conductcitation

    Isolated microfilariae were identified on the basis of their morphometrical characteristics.

    “Isolated microfilariae were identified on basis of their morphometrical characteristics (Zajac & Conboy, 2012).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Zajac & Conboy, 2012

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    Both arthropods and infected dogs could be responsible for the occurrence of several zoonotic diseases, particularly T. canis, Taenia sp. (refers to E. granulosus), B. burgdorferi and hookworms.

    “Therefore, both the arthropods and infected dogs could be responsible for occurrence of several zoonotic diseases; particularly T. canis, Taenia sp. (refers to E. granulosus), B. burgdorferi and hookworms.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The 172 owned outdoor dogs sampled from the specified regions are representative of outdoor dogs in Bulgaria.
    • Rests on an assumption: The diagnostic methods used (flotation, sedimentation, Knott’s technique, SNAP 4Dx Plus Test, and Angio Detect Test) have sufficient sensitivity and specificity to estimate the prevalence of the targeted pathogens.
    • Rests on an assumption: Seropositivity for Ehrlichia sp., Anaplasma sp., and Borrelia burgdorferi indicates infection with these pathogens.

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

    Study design and conductnone given

    Both assays were performed according to the manufacturer's instructions.

    “Both assays were performed according to manufacturer’s instructions.”
    Quote in the paperNot a substantial claim
4 of 4

  • The paper relies on this without support.

    The 172 owned outdoor dogs sampled from the specified regions are representative of outdoor dogs in Bulgaria.

    “This study was performed from July 2016 to September 2017 on 172 owned dogs (115 males and 57 females) aged from 1 month to 12 year, reared outdoor. The animals were recruited from outskirts of Rousse (43º50’N, 25º57’E), Razgrad (43º32’N, 26º32’E), Sofia (42º41’N, 23º19’E) (Northern Bulgaria), Stara Zagora (42º25’N, 25º38’E), and Plovdiv (42º8’N, 24º44’E) (Southern Bulgaria).”
    “This study presents an overview of the prevalence of GI parasites and some vector-borne helminths and bacteria in outdoor dogs in Bulgaria as well as the first report of A. vasorum.”

  • The paper relies on this without support.

    The diagnostic methods used (flotation, sedimentation, Knott’s technique, SNAP 4Dx Plus Test, and Angio Detect Test) have sufficient sensitivity and specificity to estimate the prevalence of the targeted pathogens.

    “Blood samples were collected by venipuncture of v. cephalica antebrachii, from each animal, into vacutainers. After clotting the samples, the sera were stored at 4ºC and assayed within 24 hours for detection of D. immitis antigens; antibodies against Anaplasma sp., Ehrlichia sp., and B. burgdorferi (SNAP® 4Dx Plus Test, IDEXX) as well as A. vasorum antigens (Angio Detect™ Test, IDEXX). Both assays”

  • The paper relies on this without support.

    Seropositivity for Ehrlichia sp., Anaplasma sp., and Borrelia burgdorferi indicates infection with these pathogens.

    “Blood samples revealed the presence of antibodies against Ehrlichia sp. (13.4%), Anaplasma sp. (13.4%) and Borrelia burgdorferi (1.7%).”
    “Our results also showed infections with Anaplasma sp. (13.4 %), Ehrlichia sp. (13.4 %) and B. burgdorferi (1.7 %).”
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?

  • In Bulgaria, recent studies reported canine heartworm prevalence between 4.8-34.7%, higher in central, eastern, and southern regions and lower in western and south-western regions.

    “In Bulgaria, recent studies reported prevalence between 4.8–34.7%, being higher in the central, eastern, and southern regions and lower in the western and south-western regions [80,81,82].”

    From What has happened to heartworm disease in Europe in the last 10 years? (2022) · cites this paper as [81]

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.

  • Reported Ehrlichia age association does not meet the stated significance threshold

    Major

    For the adult-versus-young comparison, χ2=3.740 with one degree of freedom corresponds to p≈0.053, above the paper's P≤0.05 threshold. The stated significant age difference for Ehrlichia sp. therefore does not follow from its reported statistic.

  • Vector-borne prevalence counts co-infections more than once

    Major

    The five named pathogens have 77 positive results in Table 1, but Table 3 shows that some dogs tested positive for multiple pathogens. Accounting for the listed co-infections gives 61 distinct dogs, or 35.5%, rather than 44.8%.

  • Incorrect percentage for a two-dog co-infection

    Minor

    The table reports 2 of 172 dogs as 2.1%; the percentage is 1.2% to one decimal place.

    Reported 2.1 · recomputed 1.162791

3 of 3

The citation lists haven’t been fetched yet

References 36 · Cited by 18

Research works printed but not linked: 8

  1. Georgieva, D., Ivanov, A., Prelesov, P. (1999): Studies on the parasitic fauna in stray dogs in the Stara Zagora region. Bulg. J. Vet. Med 2(2-3): 121 - 124
  2. Georgieva, D., Kirkova, Z., Ivanov, I. (2001): The study on the incidence and diagnostic of dirofilariosis (heartworm disease) in carnivores. Bulg. J. Vet. Med 4(4): 231 - 236
  3. Ilie, M., Imre, M., Imre, K., Hora, F., Darabus, G., Jurca, A., Patras, I., Sorescu, D. (2016): Prevalence of Angiostrongylus vasorum infestation in dogs from western Romania – preliminary results. Lucrari Stiintifice: Med. Vet. Timisoara 49(3): 78 - 81
  4. Iliev, P., Kirkova, Z., Ivanov, I., Prelesov, P., Tonev, A., Kalkanov, I. (2017): Retrospective analysis on helminthic and protozoan infections in dogs and cats in Bulgaria. Bulg. J. Vet. Med 20(1): 389 - 393
  5. Kirkova, Z., Iliev, P., Silaghi, C., Rehbein, S., Knaus, M. (2013): Fecal examinations in dogs Canis familiaris in Bulgaria. In Abstracts of Tagung der DVG Fachgruppe “Parasitologie and Parasitäre Krankheiten”, July 8-10, 2013 Gießen, Germany: Hauptgebäude der Justus Liebig-Universität, Gießen, Germany, 2013, pp.30-31
  6. Lalkovski, N., Sabev, P. (2009): The prevalence of helminth and protozoan parasites in dogs in Sofia, Bulgaria. In Abstracts of International Scientific and Practical Conference NDNIVMI, May 21, 2009 Sofia, Bulgaria: The National Diagnostic Science-and-Research Veterinary Medical Institute, Sofia, Bulgaria, 2009, pp.169 (In Bulgarian)
  7. Ursache, A., Gyorke, A., Mircean, V., Matei, I., Cozma, V. (2016): Prevalence of Toxocara canis and other endoparasites in client-owned dogs from Cluj county, Romania. Sci. Parasitol 17(3-4): 101–107
  8. Zajac, A., Conboy, G. (2012): Veterinary Clinical Parasitology 8th Edition, Chichester, UK, Wiley-Blackwell, pp. 188 - 201

Authors
Iliev, P. T., Kirkova, Z. T., & Tonev, A. S.
Affiliations
Trakia University (BG)
Corresponding author
Iliev, P. T.
ORCID
Venue
Helminthologia
Publisher
Walter de Gruyter GmbH
Published
2020-05-23
Volume
57
Issue
2
Pages
171-178
ISSN
  • 0440-6605 (ISSN-L)
  • 1336-9083
DOI
10.2478/helm-2020-0016
PMC
PMC7261023
OpenAlex
W3031844464
Cited by
18
References
36
Citations by year
2026: 2 · 2025: 1 · 2024: 4 · 2023: 2 · 2022: 5 · 2021: 3 · 2020: 1
FWCI
2.63
Type
journal article
Language
en
Open access
Licence
Locations
  • Helminthologia (publishedVersion, cc-by-nc-nd)
  • PubMed Central (publishedVersion, cc-by-nc-nd)
  • PubMed (publishedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion)
Topics
  • Health Sciences › Veterinary › Small Animals › Helminth infection and control
  • Life Sciences › Immunology and Microbiology › Parasitology › Vector-borne infectious diseases
  • Health Sciences › Medicine › Pathology and Forensic Medicine › Parasitic infections in humans and animals
Keywords
gastrointestinal parasites, vector-borne diseases, hookworm, Ancylostoma, Uncinaria, Trichuris vulpis, Capillaria, Toxocara canis, Ehrlichia, Anaplasma, Borrelia burgdorferi, Dirofilaria immitis, Angiostrongylus vasorum, Dirofilaria repens, co-infection, prevalence, Bulgaria

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