Detection of Leishmania infantum in animals and their ectoparasites by conventional PCR and real time PCR

Abstract

Visceral leishmaniosis (VL) is a parasitic disease caused by Leishmania infantum, which is primarily transmitted by phlebotomine sandflies. However, there has been much speculation on the role of other arthropods in the transmission of VL. Thus, the aim of this study was to assess the presence of L. infantum in cats, dogs and their ectoparasites in a VL-endemic area in northeastern Brazil. DNA was extracted from blood samples and ectoparasites, tested by conventional PCR (cPCR) and quantitative real time PCR (qPCR) targeting the L. infantum kinetoplast DNA. A total of 280 blood samples (from five cats and 275 dogs) and 117 ectoparasites from dogs were collected. Animals were apparently healthy and not previously tested by serological or molecular diagnostic methods. Overall, 213 (76.1 %) animals and 51 (43.6 %) ectoparasites were positive to L. infantum, with mean parasite loads of 795.2, 31.9 and 9.1 fg in dogs, cats and ectoparasites, respectively. Concerning the positivity between dogs and their ectoparasites, 32 (15.3 %) positive dogs were parasitized by positive ectoparasites. The overall concordance between the PCR protocols used was 59.2 %, with qPCR being more efficient than cPCR; 34.1 % of all positive samples were exclusively positive by qPCR. The high number of positive animals and ectoparasites also indicates that they could serve as sentinels or indicators of the circulation of L. infantum in risk areas.

Dogs, cats, parasites, and humans in Brazil: opening the black box

“… a Checklist of endoparasites (protozoa and helminths) affecting cats in Brazil [42,44,47,71,87,90,92,97],[129,131-148,346,349,352-356]. Doubtful records (e.g., Ascaridia galli  and Heterakis gallinarum ) [68,69] are not included.…”

Transmission routes of visceral leishmaniasis in mammals

“…(DANTAS-TORRES et al, 2010a). Furthermore, the DNA of L. infantum has been found in dogs and ticks that were parasitizing these animals (MORAIS et al, 2013). These results, however, did not confirm the vectorial capacity of this species, since the maintenance of the parasite epidemiological cycle and transmissibility for dogs have not been proved.…”

“…The above reinforces the theory of SHERLOCK (1964) who reported that transmission could probably be made by other vectors when sandflies are absent. Ticks (Rhipicephalus sanguineus) and fleas (Ctenocephalides felis felis) are among these possible alternative vectors (COUTINHO et al, 2005;COUTINHO & LINARDI, 2007;MORAIS et al, 2013).…”

“…However, alternative routes of transmission have been described in dogs and man (TURCHETTI et al, 2014). In dogs, there are reports of sexual (SILVA et al, 2009a) and vertical transmission (NAUCKE & LORENTZ, 2012), by blood transfusion (DE FREITAS et al, 2006) and by other vectors such as fleas and ticks which may be involved in the epidemiology of the disease (MORAIS et al, 2013).…”

Leishmania infantum infection in dogs from maroon communities in the Eastern Amazon

“…Dogs are important domestic reservoirs of L. infantum, and might serve as sentinels or indicators of the circulation of this etiologic agent in risk areas (MORAIS et al, 2013).…”