Relationship betweenLeishmaniaIFAT Titer and Clinicopathological Manifestations (Clinical Score) in Dogs

Abstract

During canine leishmaniasis (CanL) due to Leishmania infantum, high levels of antibodies production are associated with the presence of various clinical signs, because of the deposition of soluble immune complexes in organs and tissues. The immunofluorescence antibody test (IFAT) is one of the most commonly used techniques for detection of anti-Leishmania antibodies. The purpose of this study was to assess whether there is a correlation between clinical signs and IFAT titers in dogs naturally infected with Leishmania. A retrospective study was performed on medical records of 49 dogs diagnosed with CanL. Information extracted from the medical records of each dog with CanL was clinical score, IFAT titer, serum total protein (TP), gamma globulin (IgG) and creatinine concentration, and protein creatinine ratio in urine sample (UP/UC) at each follow-up examination. Results show that dogs with highest IFAT titers recorded had higher mean clinical scores indicating a positive relationship (P < 0.0001) between anti-Leishmania antibodies (IgG) and clinical manifestations, which becomes more evident in severe clinical forms of canine leishmaniasis. Higher TP and IgG serum concentrations were recorded in dogs with higher clinical scores. Significant association was observed between UP/UC and the IFAT titer (P = 0.004).

Course of experimental infection of canine leishmaniosis: Follow-up and utility of noninvasive diagnostic techniques

“…On D360, all dogs showed higher antibody titers (range 1/3200-1/12,800) than those found in other experimental infections, where the method's detection limit was over 1/400 (Rosypal et al, 2005) or 1/640 . Although IFAT titers and clinical signs could not be correlated, highest antibody levels (1/12,800) were recorded in the two dogs showing the highest clinical scores, as previously described (Proverbio et al, 2014).…”

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

“…Manna et al (2009) also created a severity clinical score that was associated with parasite load in CVL; however, this severity score was not compared with those of sick dogs without CVL to establish its diagnostic power. Other studies have demonstrated a model based on a scoring system combining the clinical signs and serological (IFAT) results as a tool to help in CVL control strategies (Proverbio et al 2014, Gouvêa et al 2016). …”

Laboratory tests for diagnosing and monitoring canine leishmaniasis

“…Serum protein analysis including electrophoresis may reveal abnormalities very early during the course of the disease . For instance, total proteins and total globulins are frequently increased, and the increase of total proteins has been shown to correlate with the severity of the clinical score . The only exception is albumin, which decreases because it is a negative APP (see below) but can also be lost due to proteinuric nephropathy, resulting in a decreased albumin‐to‐globulin (A/G) ratio .…”

“…Antibody titers will be high when the disease is evident in dogs classified as sick or very sick by CLWG classification or stage II, III, or IV (mild, severe, or very severe disease) by the Leishvet classification . While a direct relationship between the clinical score and antibody titers exists, low‐to‐medium antibody titers may also be detected in dogs with clinical signs. These have been classified as stage I or II (mild or moderate disease) according to the Leishvet classification …”

“…17 For instance, total proteins and total globulins are frequently increased 14,15,65,81,103 , and the increase of total proteins has been shown to correlate with the severity of the clinical score. 104 The only exception is albumin, which decreases because it is a negative APP (see below) but can also be lost due to proteinuric nephropathy, resulting in a decreased albumin-to-globulin (A/G) ratio. 65,103 The decrease of the A/G ratio is so frequent that it has been considered by some authors to be one of the most sensitive tests for canine leishmaniasis 103 , and hypoalbuminemia is considered a negative prognostic factor in leishmaniotic dogs.…”