Utility of Diagnostic Tests Used in Diagnosis of Infection in Dogs Experimentally Inoculated with a North American Isolate of Leishmania infantum infantum

Abstract

Eight female beagles were infected with 1 x 10(7) (low dose, LD) or 2 x 10(8) (high dose, HD) promastigotes of a North American isolate of Leishmania infantum infantum (LIVT-1 strain) isolated from naturally infected Virginia Foxhounds. Two female beagles served as negative controls and 2 male beagles chronically infected (> 3 years) with Leishmania infantum chagasi were positive controls. Bone marrow (BM) and lymph node (LN) aspirates were collected every 6-8 weeks for cytologic evaluation, parasite culture, and polymerase chain reaction (PCR). Serum samples were collected monthly for determination of serologic responses by indirect fluorescent antibody test (IFAT) and diagnostic rK39 antigen. Cultures of BM and LN aspirates and cytology evaluation were consistently positive in positive control dogs during the course of study. Negative control dogs were negative on BM and LN cultures and on cytologic evaluation of aspirates. Amastigotes were present on cytological examination of BM aspirates in 2 experimentally infected dogs. Cultures of LN aspirates were positive on 22 samples, whereas BM cultures were positive on 12 samples for all dogs. IFA titers ranged from 0 to 1 :400 in experimentally infected dogs during the course of the study. Recombinant K39 immunoassay tests were consistently positive in positive control dogs and in the HD dogs by approximately 8 weeks after infection. BM PCR products were identified more consistently in the HD dogs compared with the LD dogs. Kappa statistics indicated PCR correlated better with cultures and cytology than did IFAT or the rK39 immunoassay results in the experimentally infected dogs.

Surveillance for Antibodies to Leishmania spp. in Dogs from Sri Lanka

“…Recently, in Sri Lanka, increasing numbers of cutaneous leishmaniasis caused by L. donovani infection have been reported and there is limited evidence suggesting that it may be a zoonotic form of the disease (Nawaratna et al, 2009). Leishmaniasis has been reported in regions of the world where it was not found previously (Rosypal et al, 2003;Shaw, 2007). Several factors influence the increased incidence of VL, including human migration, HIV co-infection, and climate change (Chappuis et al, 2007;Shaw, 2007).…”

“…antibodies. There are several serological methods used for detection of Leishmania sp.-specific antibodies, including the indirect fluorescent antibody test (IFAT), complement fixation, direct agglutination, enzyme-linked immunosorbent assay, and ICT dipstick tests (Rosypal et al, 2003;Lira et al, 2006). The IFAT is the most commonly used of all serological assays and represents the ''gold standard'' with which other serological tests are compared (Rosypal et al, 2003).…”

“…There are several serological methods used for detection of Leishmania sp.-specific antibodies, including the indirect fluorescent antibody test (IFAT), complement fixation, direct agglutination, enzyme-linked immunosorbent assay, and ICT dipstick tests (Rosypal et al, 2003;Lira et al, 2006). The IFAT is the most commonly used of all serological assays and represents the ''gold standard'' with which other serological tests are compared (Rosypal et al, 2003). Serological tests are not 100% sensitive and specific; however, several studies using the recombinant antigens in the ICT demonstrated high specificity compared to traditional serological assays (Burns et al, 1993;Rosypal et al, 2005Rosypal et al, , 2007.…”

“…The IFAT is the most commonly used of all serological assays and represents the ''gold standard'' with which other serological tests are compared (Rosypal et al, 2003). Serological tests are not 100% sensitive and specific; however, several studies using the recombinant antigens in the ICT demonstrated high specificity compared to traditional serological assays (Burns et al, 1993;Rosypal et al, 2005Rosypal et al, , 2007. In addition, the ICT assay used in the present study is now considered to be the best available test for field diagnosis of VL in remote geographic regions (Chappuis et al, 2007).…”

“…Parasitol., 96(1), 2010, pp. 230-231 F American Society of Parasitologists 2010 zymodemes have been described (Cupolillo et al, 2003;Rosypal et al, 2005).…”