Investigation of canine visceral leishmaniasis in a non-endemic area in Brazil and the comparison of serological and molecular diagnostic tests

Abstract

INTRODUCTION: Visceral leishmaniasis (VL) is an important zoonosis in Brazil. Previous identification of parasitized dogs can also help prevent the disease in humans, even in non-endemic areas of the country. The Brazilian Ministry of Health recommends diagnosis in dogs using a DPP ® (rapid test) as a screening test and an immunoenzymatic assay (ELISA) as a confirmatory test (DPP ® +ELISA), and culling infected dogs as a legal control measure. However, the accuracy of these serological tests has been questioned. METHODS: VL in dogs was investigated in a non-endemic area of the São Paulo state for three consecutive years, and the performances of different diagnostic tests were compared. RESULTS: A total of 331 dog samples were collected in 2015, 373 in 2016, and 347 in 2017. The seroprevalence by DPP ® +ELISA was 3.3, 3.2, and 0.3%, respectively, and by indirect immunofluorescence assay (IFA), it was 3.0, 5.6, and 5.5%, respectively. ELISA confirmed 18.4% of DPP ® positive samples. The concordance between the IFA and DPP ® was 83.9%. The concordance between IFA and DPP ® +ELISA was 92.9%. A molecular diagnostic test (PCR) was performed in 63.2% of the seropositive samples, all of which were negative. CONCLUSIONS: In non-endemic areas, diagnostic tests in dogs should be carefully evaluated to avoid false results.

Canine Leishmaniasis in Southern Brazil: Diagnosis and Clinical Features in Domestic Dogs

“…Noteworthy, the whole diagnostic performance is influenced by the time of infection, sample collection, vaccination status, immunosuppressing diseases, and other factors. Therefore, the use of two or more methods, including PCR, would be very welcome for a definitive diagnostic [18,23]. In addition, qPCR is a useful method to report the parasites load.…”

“…Currently, the complete diagnosis procedure includes a rapid chromatographic immunoassay (dual-path platform-DPP ® ) as a screening test, and the enzyme-linked immunosorbent assay (ELISA) is used as a confirmatory test. As serological tests have been questioned, especially regarding accuracy, PCR-based assays have also been included for a more comprehensive diagnosis [18].…”

Canine Leishmaniasis in a Recent Endemic Region in Southern Brazil

“…Noteworthy, the whole diagnostic performance is influenced by the time of infection, sample collection, vaccination status, immunosuppression diseases and other factors. Therefore, the use of two or more methods, including PCR, would be very welcome for a definitive diagnostic [18,23]. In addition, qPCR is a useful method to report the parasites load.…”

“…Currently, the complete diagnosis procedure includes a rapid chromatographic immunoassay (dual-path platform -DPP®) as screening test, and the enzyme-linked immunosorbent assay (ELISA) as confirmatory test. As serological tests have been questioned, especially regarding the accuracy, PCR based assays have also been included for a more comprehensive diagnosis [18].…”

Prevalence and risk factors of canine leishmaniasis in Morocco: a systematic review and meta-analysis

“…In Morocco, human visceral leishmaniasis was classically known to be endemic in the northern regions where outbreaks of canine leishmaniasis were proven to be active (Guessous-Idrissi et al, 1997; Nejjar et al, 1998;Sahibi et al, 2001;Lemrani et al, 2002). Prior identi cation of parasitized dogs can also help prevent disease in humans, even in non-endemic areas of the country (Sevá et al, 2021). On this basis, the Moroccan Ministry of Health granted, within the framework of its national leishmaniases control program, a strategic focus on the control of the canine reservoir which included, among others, measures for the elimination of sick stray dogs (Ministry of Health, 2010).…”