Parasite density and impaired biochemical/hematological status are associated with severe clinical aspects of canine visceral leishmaniasis

Abstract

We have performed a detailed investigation in 40 dogs naturally infected with Leishmania infantum (syn. chagasi), subdivided into three groups: asymptomatic (AD = 12), oligosymptomatic (OD = 12) and symptomatic (SD = 16), based on their clinical features. Twenty non-infected dogs (CD) were included as control group. Serological analysis, performed by IFAT and ELISA, demonstrated higher antibodies titers in SD in comparison to the AD. A positive correlation was found between parasite density in the spleen and skin smears as well as the bone marrow parasitism with clinical status of the infection. We observed that the progression of the disease from asymptomatic to symptomatic clinical form was accompanied by intense parasitism in the bone marrow. It is likely that this led to the impaired biochemical/hematological status observed. Finally, we believe that the follow-up of these parameters could be a relevant approach to be used as markers during therapeutic and vaccine evaluations.

Efficacy of Amphotericin-B, Clinicopathologic Variables and Oxidative Stress Markers in three Staffordshire Bull Terrier Dogs with Visceral Leishmaniasis

“…Symptomatic dogs demonstrate severe anemia, with a significant decrease in the number of erythrocytes, hemoglobin, and hematocrit (Reis et al, 2006;Freitas et al, 2012). Similarly, in this study, decreases in erythrocyte, hemoglobin, and hematocrit level due to lipid peroxidation development in case 3 were detected before treatment regarding the infection.…”

Relationship between clinical and pathological signs and severity of canine leishmaniasis

“…On the other hand, the existence of a correlation between anemia and the severity of the disease is still controversial. Although a correlation between anemia and clinical signs has been reported previously (AMUSATEGUI et al, 2003;REIS et al, 2006b), this was not confirmed in the study of Costa-Val et al (2007). This knowledge is important to understand the pathogenesis of CVL, as well as to evaluate the potential use of these clinical and pathological parameters to aid diagnostics and therapeutic monitoring.…”

“…Although the literature contains many reports of clinical and laboratory findings on CVL, the approach employed often favors the individual analysis of parameters (SLAPPENDEL, 1988; (AMUSATEGUI et al, 2003;REIS et al, 2006b;COSTA-VAL et al, 2007). In this study, the clinical classification was chosen because of its widespread adoption in the literature of both the Old and New World, whether in natural or experimental infection (PINELLI et al, 1994(PINELLI et al, , 1995TRAVI et al, 2001;FERNÁNDEZ-PÉREZ et al, 2003;COSTA-VAL, 2004;REIS et al, 2006a, b).…”

“…It is likely that more than one factor is involved in the etiology of anemia, such as hemorrhage, hemolysis, chronic renal failure, bone marrow hypoplasia or aplasia, and decreased lipid fluidity of the erythrocyte membrane (SLAPPENDEL; GREENE, 1990;BURILLO et al, 1994;KOUTINAS et al, 1999;DE LUNA et al, 2000). Although the pathogenesis of anemia in CVL is multifactorial, the fact that 50 to 70% of patients present normocytic/normochromic and non-regenerative anemia (CIARAMELLA et al, 1997;KOUTINAS et al, 1999;REIS et al, 2006b) suggests, at the very least, that erythropoiesis is often compromised due to infectioninduced changes in bone marrow and/or kidneys (KOUTINAS et al, 1999). In the present survey, the individual analysis of all the dogs indicated that anemia was normocytic/normochromic and non-regenerative.…”

“…In addition, high parasite loads in the components of mononuclear phagocyte system (MPS), e.g., in bone marrow and liver, triggering the occurrence of clinical pathology related to hepatic and hematopoietic functions (KEENAN et al, 1984b;AMUSATEGUI et al, 2003). Considering that parasite density in tissues increase according to the severity of clinical manifestations (GIUNCHETTI et al, 2006;REIS et al, 2006b), symptomatic dogs present significantly decreased levels of albumin and increased levels of globulin fraction, leading to an inversion of A/G ratio when compared to asymptomatic dogs, suggesting a relationship between the presence of exacerbated clinical forms of CVL, serum protein levels and humoral immune response alterations (GIUNCHETTI et al, 2006(GIUNCHETTI et al, , 2008REIS et al, 2006b). Biochemical findings in CVL include alterations in the hepatic enzymes aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase (SLAPPENDEL, 1988;ABRANCHES et al, 1991).…”