A comparative study of nested-PCR and direct agglutination test (DAT) for the detection of Leishmania infantum infection in symptomatic and asymptomatic domestic dogs

Behnaz Akhoundi,Abbas Rahimi-Foroushani,Yonas Yimam Ayene,Mohammad Javad Abbaszadeh Afshar,Mehdi Mohebali,Homa Hajjaran,Z. Zarei,Saeedeh Shojaee

doi:10.1186/s13104-021-05654-0

Behnaz Akhoundi, Abbas Rahimi-Foroushani + Show 6 more

Open Access

https://doi.org/10.1186/s13104-021-05654-0

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Abstract

ObjectiveCanine visceral leishmaniasis (CVL) is the main source of human visceral leishmaniosis (HVL) in Mediterranean region, including Iran and is spread from domestic dogs to Phlebotomine sand flies vectors to humans. To control the transmission of HVL, early and accurate detection of infected dogs is paramount importance despite it remains a confronting challenge. Herein, we evaluated the performance of direct agglutination test (DAT) against gold standard nested polymerase chain reaction (nested-PCR) for CVL diagnosis in symptomatic and asymptomatic domestic dogs from endemic areas of Iran.ResultsVenous blood samples were collected from dogs without clinical signs (n = 30) and with clinical signs (n = 35) suggestive of Leishmania infantum infection. Among 65 samples examined, Leishmania DNA was detected by nested-PCR in 89.23% (58/65). Furthermore, 86.15% (56/65) nested-PCR positive samples were also DAT positive. The results of the DAT sensitivity test were 96.43% and 96.67% in symptomatic and asymptomatic dogs, respectively, while the specificity was 100.00% and 60.00% in symptomatic and asymptomatic dogs, respectively. The results of this study also pointed out substantial concordance between DAT test and nested-PCR method in both symptomatic dogs (Κ = 0.783; P < 0.001) and asymptomatic dogs (Κ = 0.618; P < 0.001). Thus, DAT represents as a simple and economic tool for initial diagnosis of CVL particularly in endemic areas of the disease.

Highlights

Visceral leishmaniasis is one of the leading lethal parasitic diseases, with a mortality rate of over 90% of human cases, and domestic dogs are known to be the main resrviour of Leishmania infantum, causative agent of human and canine visceral leishmaniasis(CVL)Leishmania-infected dogs may exhibit a spectrum of clinical manifestation of the disease, or remain asymptomatic seropositive dogs, depending on the balance between humoral and cellular immune responses [6, 7]
Using Direct agglutination test (DAT) test, 27 (90.5%) and 31 (88.57%) of symptomatic and asymptomatic dogs were tested positive for Canine visceral leishmaniasis (CVL), respectively, while the result of nested-PCR showed, 30 (85.71%) asymptomatic and 28 (93.33%) symptomatic dogs were found to be infected with CVL
Nested-PCR was able to detect Leishmanial DNA in two dogs that were not able to detect by DAT

Summary

Introduction

Visceral leishmaniasis is one of the leading lethal parasitic diseases, with a mortality rate of over 90% of human cases (if left untreated), and domestic dogs are known to be the main resrviour of Leishmania infantum, causative agent of human and canine visceral leishmaniasis(CVL)Leishmania-infected dogs may exhibit a spectrum of clinical manifestation of the disease, or remain asymptomatic seropositive dogs, depending on the balance between humoral and cellular immune responses [6, 7]. Direct agglutination test (DAT) is one of the most widely used diagnosis method for routine laboratory diagnosis and large sero-epidemiological studies in endemic countries like Iran [17]. It doesn’t require expertise, it is cost-effective and appropriate for field use [18,19,20]. This study was carried out to evaluate the accuracy of DAT for detection of CVL against nested polymerase chain reaction (nestedPCR) from sera samples of symptomatic and asymptomatic domestic dogs in endemic areas of Iran

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Discussion

Conclusion