Canine visceral leishmaniasis: Detection of Leishmania spp. genome in peripheral blood of seropositive dogs by real-time polymerase chain reaction (rt-PCR).

Visceral leishmaniasis (VL) is a zoonosis caused by the protozoa of the genus Leishmania. Among the species, L. infantum and/or L. infantum (chagasi) are the most important species affecting the Americas. Domestic dogs are the main reservoir of the parasite and participate effectively in the parasite' transmission cycle. The Canine Visceral Leishmaniasis Control Program (PCLV) adopted in Brazil present as strategies the vector control, health education and serological diagnosis of CVL in dogs followed by culling of the seropositive ones. The resolution to eliminate seropositive dogs by euthanasia, when necessary, are the most controversial and least accepted by society. The diagnostic methods for canine visceral leishmaniasis, currently indicated and approved in Brazil by the Ministry of Health from Brazil are the Dual Path Platform (DPP)® as a screening test and the Enzyme immunoassay test (ELISA®). This study aimed to verify the presence of Leishmania spp. DNA in peripheral blood samples of dogs presenting positive serological results byDPP® and ELISA® tests,throughreal-time polymerase chain reaction (rt-PCR), using the pair of primers 150-152 already described. For this purpose, were collected blood samples from 185 seropositive dogs among them, 41 (22%) exhibited some clinical signal of disease, whereas 144 (78%) was asymptomatic. The animals were also analyzed according to gender, race and hair size. According to the results of rt-PCR, it was observed that among the185 seropositive dogs analyzed, only 132 (71%) presented positive results for CVL and 53 (29%) presented negative results. From this, 41/41 symptomatic dogs were positive (100%), while among the asymptomatic dogs, 91/144 were positive (63, 2%) and 53/144 were negative (36, 8%). Concerning the hair size of seropositive dogs, we found that 41 (22%) had long hair, while 144 (78%) had short hair. No statistical significance occurred between the results of rt-PCR, ELISA and DPP tests and the profile of the animals (gender, size of the dogs and hair size), probably due to the small number of samples and the sampling differences of each profile. But statistical significance occurred between the results of rt-PCR and the clinical evaluation, since the rt-PCR was positive in all symptomatic dogs. Thus, through these results, we reached at the following question, which may contribute to an important current debate: the dogs presenting CVL seropositive diagnosis confirmed by tests distributed by the Ministry of Health were in reality ill or were they seropositive by living in an endemic area of the disease? Would these asymptomatic seropositive dogs spread the disease to the inhabitants even presenting a low parasite charge circulating in the blood.

Paracoccidioidomycosis: Detection of Paracoccidioides brasiliensis´ genome in biological samples by quantitative chain reaction polymerase (qPCR).

Paracoccidioidomycosis (PCM) is a chronic mycosis caused by the saprobic and dimorphic species Paracoccidioides brasiliensis and P. lutzii. This disease is prevalent in Latin American countries. PCM appears as a relevant concern and challenge for the mycologists, since until now there is no a methodology suitable for an efficient and safe diagnosis and species identification. Thus, the present study aimed to validate a methodology for PCM´s diagnosis, using quantitative Polymerase Chain Reaction (qPCR) through target amplification of the gene encoding the recombinant protein Pb27, a common protein to the both species Paracoccidioides brasiliensis and P. lutzii. The experiments were performed in vitro to determine the specificity, efficiency and detection limit of qPCR assay, using specific primers and probe, which sequences were subject to a patent deposited in Brazilian CTIT, under the registration number: BR1020160078830. According to the results the technique showed sensitivity of 94% and specificity of 100%, demonstrating that it will be possible to develop a new fast and safe diagnostic PCM and can be standardized in order to present a low cost, accessible to the patient served by the public health system in Brazil and Latin America.