Biological and Genetic Heterogeneity in Trypanosoma dionisii Isolates from Hematophagous and Insectivorous Bats

This study describes the morphological, biochemical, and molecular differences among Trypanosoma dionisii isolates from hemocultures of hematophagous (Desmodus rotundus; n = 2) and insectivorous (Lonchorhina aurita; n = 1) bats from the Atlantic Rainforest of Rio de Janeiro, Brazil. Fusiform epimastigotes from the hematophagous isolates were elongated, whereas those of the insectivorous isolate were stumpy, reflected in statistically evident differences in the cell body and flagellum lengths. In the hemocultures, a higher percentage of trypomastigote forms (60%) was observed in the hematophagous bat isolates than that in the isolate from the insectivorous bat (4%), which demonstrated globular morphology. Three molecular DNA regions were analyzed: V7V8 (18S rDNA), glycosomal glyceraldehyde 3-phosphate dehydrogenase gene, and mitochondrial cytochrome b gene. The samples were also subjected to multilocus enzyme electrophoresis and random amplified polymorphic DNA analysis. All isolates were identified as T. dionisii by phylogenetic analysis. These sequences were clustered into two separate subgroups with high bootstrap values according to the feeding habits of the bats from which the parasites were isolated. However, other T. dionisii samples from bats with different feeding habits were found in the same branch. These results support the separation of the three isolates into two subgroups, demonstrating that different subpopulations of T. dionisii circulate among bats.

Genotypic profiles of Leishmania (Viannia) braziliensis strains from cutaneous leishmaniasis patients and their relationship with the response to meglumine antimoniate treatment: a pilot study

Background: Forty-four strains isolated from a cohort of cutaneous leishmaniasis (CL) patients who did or did not respond to one course of treatment with meglumine antimoniate were investigated to explore genetic polymorphisms in parasite kinetoplast DNA minicircles. Leishmania (Viannia) braziliensis strains isolated from responder (R) and non-responder (NR) patients who acquired infection in Rio de Janeiro or in other Brazilian states were studied using low-stringency single-specific primer polymerase chain reaction (LSSP-PCR) to identify genetic polymorphisms. Results: Polymorphisms were observed in parasites recovered from patient lesions. No association was found between a specific genotype and R or NR patients. Phenetic analysis grouped the genotypes into three main clusters, with similarity indices varying from 0.72 to 1.00. Although no specific genotype association was detected, at least one group of L. (V.) braziliensis genotypes that circulates in Rio de Janeiro was discriminated in clusters I and III, showing phenotypes of good and poor responses to treatment, respectively. Cluster I comprised parasite profiles recovered from R patients from Rio de Janeiro and in cluster III, NR samples were prevalent. Cluster II comprised 24 isolates, with 21 from Rio de Janeiro and three from other states, equally distributed between R and NR patients. Additionally, we found that parasites sharing all common genetic characteristics acted differently in response to treatment. Conclusions: These results are of clinical-epidemiological importance since they demonstrate that populations of L. (V.) braziliensis that exhibit high levels of genetic similarity also display different phenotypes associated with meglumine antimoniate responses in cutaneous leishmaniasis patients.

Clinical and laboratory profiles of patients with early spontaneous healing in cutaneous localized leishmaniasis: a historical cohort study

BACKGROUND

Skin ulcers in American cutaneous leishmaniasis (ACL) may heal spontaneously after months/years. However, few cases may present quick heal even during diagnosis procedure (early spontaneous healing- ESH). The main objective of this study was to compare ESH patients with cases requiring specific treatment [non-ESH (NESH)].

METHODS

A historical cohort study of ACL patients (n = 445) were divided into 2 groups: ESH - spontaneously healed patients (n = 13; 2.90%), and NESH- treated patients (n = 432; 97.10%). We compared clinical and laboratorial findings at diagnosis, including the lesion healing process.

RESULTS

ESH patients had a higher percentage of single lesions (p = 0.027), epithelialized lesion on initial examination (p = 0.001), lesions located in the dorsal trunk (p = 0.017), besides earlier healing (p < 0.001). NESH presents higher frequency of ulcerated lesions (p = 0.002), amastigotes identified in histopathology exams (p = 0.005), positive cultures (p = 0.001), and higher positivity in ≥3 parasitological exams (p = 0.030). All ESH cases were positive in only a single exam, especially in PCR.

CONCLUSIONS

ESH group apparently presented a lower parasitic load evidenced by the difficulty of parasitological confirmation and its positivity only by PCR method. The absence or deficiency of specific treatment is commonly identified as predisposing factors for recurrence and metastasis in ACL. However, due to the drugs toxicity, the treatment of cases which progress to early spontaneous healing is controversial. ESH patients were followed for up to 5 years after cure, with no evidence of recrudescence, therefore suggesting that not treating these patients is justifiable, but periodic dermatological and otorhinolaryngological examinations are advisable to detect a possible relapse.

Molecular study of Trypanosoma caninum isolates based on different genetic markers

Trypanosoma caninum is a parasite recently described in dogs, whose life cycle is rather unknown. Here, we performed a genetic study with T. caninum samples obtained in different Brazilian regions. The study was based on PCR assays target to small and large subunit ribosomal DNA (rDNA) (18S rDNA and 24Sα rDNA), cytochrome B (Cyt b), and internal transcribed spacer 1 rDNA (ITS1 rDNA) following by the sequence analysis. Additionally, we used primers for the variable regions of kinetoplast DNA (kDNA) minicircles and endonucleases restriction in the ITS1 rDNA amplification product. T. caninum samples displayed the same patterns. Tree construction confirmed the close relationship between T. caninum samples, regardless of the molecular target used and endonuclease restriction digestion revealed that all samples have the same restriction profile. Therefore, T. caninum seems to be a genetically homogeneous specie. In the kDNA assay, T. caninum possessed a different molecular size profile with respect to others trypanosomes, 330 and 350 bp. This study provides nucleotide sequences from different regions of the genome of T. caninum that certainly facilitate future studies.

Aflagellar epimastigote forms are found in axenic culture of Trypanosoma caninum

Representatives of the genus Trypanosoma have been traditionally found in epimastigote, espheromastigote and trypomastigote flagellated forms in axenic cultures. Trypanosoma caninum is a trypanosomatid that has recently been reported infecting dogs in endemic areas of canine leishmaniasis in Brazil. It presents specific biological characteristics and it is found exclusively on healthy skin. Here, we describe the evolutive forms of this parasite showing not only the forms commonly found in culture, but also epimastigote forms with no free flagellum. The study was conducted using scanning and transmission electron microscopy and, we demonstrate that typical flagellated epimastigotes originate from forms without flagellum, although the latter may remain without differentiation in the culture. Two hypotheses are considered and discussed in this paper: (i) the aflagellated epimastigotes are a typical developmental forms of T. caninum and (ii) the emergence of these aflagellated forms could be resultant from a disturbed process during cell division caused by interfering specific proteins, which leads to inability to form and regulate the flagellum length. In any case, considering that T. caninum is a parasite that is still little studied, the information brought by our study adds data which may be useful to clarify aspects on the cell cycle of this intriguing parasite that has been found in different regions of Brazil.

PCR associated with molecular hybridization detects Leishmania (Viannia) braziliensis in healthy skin in canine tegumentary leishmaniasis

Tegumentary leishmaniasis (TL) is a zoonotic disease that affects humans and domestic dogs. In Brazil, TL is considered endemic, and Leishmania (Viannia) braziliensis is the prevalent species causing this disease. There is debate about the role of dogs (Canis familiaris) as domestic reservoirs in the transmission cycle of TL. To date, classical parasitological techniques, including parasite isolation in culture media, have been able to detect parasites only from cutaneous lesions. In this study, we detected L. (V.) braziliensis DNA in intact skin fragments collected from 3 naturally infected dogs from the state of Rio de Janeiro, Brazil, with the use of PCR techniques associated with molecular hybridization. The detection of parasitic DNA in this anatomical site is an important finding vis-à-vis the importance of the domestic dogs in endemic areas of TL.

Leishmania (Leishmania) hertigi in a porcupine (Coendou sp.) found in Brasília, Federal District, Brazil

Studies report the occurrence of Leishmania (Leishmania) hertigi in northern states of Brazil. In the present investigation, we describe the isolation of L. (L.) hertigi from a porcupine (Coendou sp.) found in Brasília, Federal District, center-west region of Brazil. During a study on canine visceral leishmaniasis conducted in the city of Brasília, Federal District, a porcupine was found dead on a public road. The animal was identified and fragments of intact skin and spleen were collected for isolation of parasite in the culture. This report of the occurrence of L. hertigi in another part of Brazil may help establish the distribution of this parasite in the country. Further studies are needed to better understand the role of L. hertigi in the pathology and pathogenesis of leishmaniasis and its survival in mammals and possible vectors.

NATURAL INFECTION BY Trypanosoma cruzi IN ONE DOG IN CENTRAL WESTERN BRAZIL: A CASE REPORT

SUMMARY It is estimated that about 10 million people are infected with Trypanosoma cruzi worldwide, mostly in Latin America and more than 25 million are at risk of acquiring this infection in endemic areas. Dogs are an important reservoir for this pathogen and thus, considered a risk factor for human populations. This report describes one case of Chagas disease in a dog from Cuiabá, Mato Grosso State, Brazil. The diagnosis was obtained by direct examination of trypomastigote forms in blood smears. Amastigotes forms were visualized in microscopy of the bone marrow, lymph nodes, kidneys, liver and brain. The T. cruzi (ZIII) infection was confirmed by Polymerase Chain Reaction, and sequencing. The animal presented multisystemic failure and died. Although acute Chagas disease in humans is not reported in Cuiabá, this is the first report of a canine case in this region. This case represents a warning, to health professionals and authorities, to the possibility of transmission of this zoonosis in Cuiabá.

Evaluation of Leishmania (Leishmania) chagasi strains isolated from dogs originating from two visceral leishmaniasis-endemic areas in Brazil using multilocus enzyme electrophoresis

INTRODUCTION: Domestic dogs are the most important reservoir in the peridomestic transmission cycle of Leishmania (Leishmania) chagasi. The genetic variability of subpopulations of this parasite circulating in dogs has not been thoroughly analyzed in Brazil, even though this knowledge has important implications in the clinical-epidemiological context. METHODS: The objective of this study was to evaluate and compare the phenotypic variability of 153 L. chagasi strains isolated from dogs originating from the municipalities of Rio de Janeiro (n = 57) and Belo Horizonte (n = 96), where the disease is endemic. Strains isolated only from intact skin were selected and analyzed by multilocus enzyme electrophoresis using nine enzyme systems (6PG, GPI, NH1 and NH2, G6P, PGM, MDH, ME, and IDHNADP). RESULTS: The electrophoretic profile was identical for all isolates analyzed and was the same as that of the L. chagasi reference strain (MHOM/BR/74/PP75). Phenetic analysis showed a similarity index of one for all strains, with the isolates sharing 100% of the characteristics analyzed. CONCLUSIONS: The results demonstrate that the L. chagasi populations circulating in dogs from Rio de Janeiro and Belo Horizonte belong to a single zymodeme.