Sensitivity and specificity of parallel or serial serological testing for detection of canine Leishmania infection

Abstract

In Brazil, human and canine visceral leishmaniasis (CVL) caused byLeishmania infantum has undergone urbanisation since 1980, constituting a public health problem, and serological tests are tools of choice for identifying infected dogs. Until recently, the Brazilian zoonoses control program recommended enzyme-linked immunosorbent assays (ELISA) and indirect immunofluorescence assays (IFA) as the screening and confirmatory methods, respectively, for the detection of canine infection. The purpose of this study was to estimate the accuracy of ELISA and IFA in parallel or serial combinations. The reference standard comprised the results of direct visualisation of parasites in histological sections, immunohistochemical test, or isolation of the parasite in culture. Samples from 98 cases and 1,327 noncases were included. Individually, both tests presented sensitivity of 91.8% and 90.8%, and specificity of 83.4 and 53.4%, for the ELISA and IFA, respectively. When tests were used in parallel combination, sensitivity attained 99.2%, while specificity dropped to 44.8%. When used in serial combination (ELISA followed by IFA), decreased sensitivity (83.3%) and increased specificity (92.5%) were observed. Serial testing approach improved specificity with moderate loss in sensitivity. This strategy could partially fulfill the needs of public health and dog owners for a more accurate diagnosis of CVL.

Accuracy of the Lee–White Clotting Time Performed in the Hospital Routine to Detect Coagulopathy in Bothrops atrox Envenomation

“…Increased sensitivity may be achieved once standardization is achieved or with the establishment of parallel or serial test combinations to increase sensitivity and specificity. 29 The LWCT performed in clinical settings should be linked to clinical signs. Local signs such as local bleeding and edema and systemic signs that include hematemesis, hematuria, and gingival and conjunctival bleeding are present depending on the severity of the accident and may aid to confirm envenomation.…”

Scoring clinical signs can help diagnose canine visceral leishmaniasis in a highly endemic area in Brazil

“…Moreover, dogs infected with T. cruzi have not yet been detected in Teresina, PI. These aspects may have contributed to the different sensitivity and specificity results obtained in the studies that used serological methods for detecting CVL (de Arruda et al 2016). …”

The use of Escherichia coli total antigens as a complementary approach to address seropositivity to Leishmania antigens in canine leishmaniosis

“…Therefore, low-accuracy serological assays can have significant impact in the global strategy to combat disease progression originating seropositivity levels that are not translatable into meaningful epidemiological data influencing policies associated with specific control measures. In fact, cumulative evidence point to a low specificity (Sp) of several serological assays that hamper the detection of Leishmania infection in dogs (Gomes et al 2008; Morales-Yuste et al 2012; Arruda et al 2016; Elshafie et al 2016; Fraga et al 2016). Moreover, detection of L. infantum vectors across central European countries like Switzerland, Germany and Hungary (Naucke et al 2008; Ready, 2010), in conjunction with global warming, might open new areas to endemicity, through the adaptation of the vectors to new latitudes (Geisweid et al 2013; Millan et al 2014).…”