[Show abstract][Hide abstract] ABSTRACT: American visceral leishmaniasis is a vector-borne zoonosis in expansion in Brazil. Dogs are the main urban reservoir. Departing from a case of canine visceral leishmaniasis (CVL) in Jacaré, Niterói, Rio de Janeiro State, an epidemiological canine and entomological study was performed to assess the extension of the disease at the location. Sample was collected around the case and the dogs identified by serological tests (rapid double platform immunochromatographic exams, immunoenzymatic assay/ELISA, indirect immunofluorescence/IFAT). The parasitological diagnosis was performed in animals positive in at least one of these tests. The entomological study was carried out by using light traps and manual collection. The associations between canine variables and outcome (ELISA and IFAT reagents) were assessed by the chi-square test and adjusted by multivariate logistic regression for those associations with p < 0.1 in the bivariate analysis. Seventeen cases of CVL were detected among 110 evaluated dogs (prevalence of 15.5%). Presence of ectoparasites (OR 6.5; 95% CI 1.1-37.4), animals with clinical signs (OR 9.5; 95% CI 1.2-76.6), and previous cases of CVL in the same house (OR 17.9; 95% CI 2.2-147.1) were associated with the outcome. Lutzomyia longipalpiswas not detected. Our results are indicative of an ongoing transmission in the area.
Revista do Instituto de Medicina Tropical de São Paulo 09/2015; 57(4):325-332. DOI:10.1590/S0036-46652015000400009 · 1.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Introduction:
Trypanosoma caninum is a protozoan species recently described in dogs, whose occurrence has been reported in areas of overlap with visceral leishmaniasis.
Trypanosoma sp. were isolated from nine dogs and characterized by molecular methods.
PCR and sequencing confirmed the presence of T. caninum in all dogs, revealing two new areas of transmission: Barra Mansa and São João do Piauí.
The nine new cases described, when added to those already published, account for 62 cases of natural infection by T. caninum and show the geographical spread of this species to new areas, where other trypanosomatids circulate.
Revista da Sociedade Brasileira de Medicina Tropical 06/2015; 48(3):347-9. DOI:10.1590/0037-8682-0307-2014 · 0.98 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Canine visceral leishmaniasisis an important zoonosis caused by the protozoa Leishmania infantum (syn. Leishmania chagasi), whose clinical manifestationsare dependent on theimmune responseexpressed by the infected animal and the virulence of the parasite. Atypical clinical forms of canine visceral leishmaniasis have been reported.The purpose of this paper was to describe a tumor-like lesion form of canine visceral leishmaniasis and to alert clinical and pathologists veterinarians to the importance of its diagnosis. Amastigote forms were observed by cytopathological, histopathological and immunohistochemistry analysis from the tumour-like lesion and Leishmania infantum was isolated by culture from spleen, liver, lymph nodes and bone marrow samples. Clinical and pathologist veterinarians should include the canine visceral leishmaniasis in the differential diagnosis of tumors and chronic affections of oral mucosa, mainly in endemic regions of the disease.
[Show abstract][Hide abstract] ABSTRACT: Introduction:
In Brazil, visceral leishmaniasis (VL) has spread to various regions. This study reports canine cases of VL in Barra Mansa, where human VL cases were recently reported.
Using the human index case, a canine survey was performed by dual-path platform immunochromatography and enzyme-linked immunosorbent assay. Seropositive animals were euthanized. Cultures were collected to detect Leishmania parasites.
Serological tests detected 141 canine VL cases, and Leishmania chagasi were isolated from 82.2% animals.
Leishmania chagasi is in circulation in Barra Mansa. This study broadens information on the parasite's distribution in the State of Rio de Janeiro.
Revista da Sociedade Brasileira de Medicina Tropical 12/2014; 47(6):788-90. DOI:10.1590/0037-8682-0042-2014 · 0.98 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Trypanosoma caninum is a new species that has been recently identified in Brazil and infects domestic dogs. To date, no accurate diagnostic assays for this parasite have been established; thus, our aim was to evaluate more than one type of PCR for the diagnosis and molecular screening of T. caninum in 229 dogs living in Rio de Janeiro state. The tests were based on the amplification and sequencing of the 18S ribosomal DNA (rDNA) gene using healthy skin fragments. Additionally, PCR amplification of the kDNA minicircles region specific to the Leishmania genus was performed. The PCR results were compared with those of culture-based analysis performed with the same specimen. Using cultures, T. caninum and Leishmania chagasi were isolated from 11 and 12 dogs, respectively, whereas the 18S rDNA PCR assay detected parasitic infection in 35 dogs. Among these, 25 dogs showed an amplification pattern similar to T. caninum and 10 showed a pattern similar to L. chagasi; these results were confirmed by sequencing analysis. The kDNA PCR analysis showed that 14 dogs were positive for Leishmania infection. Of these, 2 dogs showed negative culture results and 12 were positive for L. chagasi, including 4 with negative 18S rDNA PCR results. Thus far, culture-based testing has been the only tool used successfully for T. caninum diagnosis. Our results demonstrate that 18S rDNA PCR-based test should be a useful diagnostic tool, particularly for distinguishing between T. caninum and L. chagasi infections in areas where these 2 parasites co-exist.
[Show abstract][Hide abstract] ABSTRACT: Background:
Visceral leishmaniasis is a major public health concern in Brazil and the domestic dog is the main source of infection. In this study, we aimed to evaluate the accuracy and reliability of a rapid chromatographic immunoassay based on a dual-path platform for the diagnosis of canine visceral leishmaniasis (CVL).
Sampling consisted of 428 domestic dogs selected from two neighborhoods in the municipality of Fortaleza, Ceara state, Brazil. The reference standard was composed of three parasitological tests and was applied samples from 333 dogs. The rapid test was used to analyse whole blood and serum samples.
Accuracy of the rapid test in whole blood samples through visual reading (n=305), serum samples through electronic reading (n=333) and serum samples through visual reading (n=333), yielded sensitivities of 87.5% (21/24; 95% CI: 66.5 to 96.7), 88% (22/25; 95% CI: 67.5 to 96.8) and 88% (22/25; 95% CI: 67.5 to 96.8), and specificities of 73.3% (206/281; 95% CI: 67.7 to 78.4), 68.2% (210/308; 95% CI: 62.2 to 74.3) and 69.2% (213/308; 95% CI: 63.7 to 74.3), respectively. Agreement between the visual and electronic readings in 428 serum samples were classified as almost perfect (Kappa Index=0.88; 95% CI: 0.83 to 0.93). The positive predictive value of the test using whole blood samples was 21.9% for the 7.9% prevalence detected by the reference standard in the study sample. A sensitivity analysis of the positive predictive value revealed that it remained below 50% in scenarios with a prevalence of up to 20%.
The similarity of the accuracy values of the rapid test using whole blood or serum samples, together with its reliable performance in sera through visual and electronic reading, suggests that it may contribute as a screening test for routine use under field-conditions. However, future studies need to improve the accuracy of the test so that it can be successfully implemented in public health programs.
Transactions of the Royal Society of Tropical Medicine and Hygiene 07/2014; 108(9). DOI:10.1093/trstmh/tru109 · 1.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Immature phlebotomine sand flies develop in soils with essential and ideal characteristics for their life cycle, such as organic matter, humidity, temperature and low levels of light. Information regarding the potential breeding places of these dipterans is fundamental to understand the epidemiology and ecology of leishmaniasis, in addition to its importance to control them. In the present study, we aimed to find natural breeding sites of sand flies on Marambaia Island with the aid of emergence traps and direct search of immature forms using the flotation technique with saturated sugar solution in organic substrates of the region. Both methods were effective, with a total of 42 specimens of six different species - including some species that participate in the transmission cycle of American Tegumentary Leishmaniasis - collected by the emergence traps, and five immature forms obtained by floatation technique. However, further studies are still necessary, mainly with respect to the ecology and biology of immature sandfly stages, so that control measures focused on breeding sites can produce positive sustainable results in natural environments.
[Show abstract][Hide abstract] ABSTRACT: In Brazil, American visceral leishmaniasis (AVL) is caused by Leishmania (Leishmania) chagasi and its main vector is Lutzomyia longipalpis. Cases of canine visceral leishmaniasis (CVL) in non-endemic areas have been reported over the last few years throughout the country. The objective of this research note is to describe an autochthonous case of CVL that occurred in the municipality of Volta Redonda, state of Rio de Janeiro, an area where the disease is not endemic, alerting veterinarians and the scientific community to the expansion of this important zoonosis and advising veterinary practitioners on how to deal with a suspicion of CVL. Canine visceral leishmaniasis can be misdiagnosed within a broad spectrum of canine diseases based on clinical and laboratory findings. Therefore, knowledge of its clinical manifestations, specific and sensitive laboratory diagnostic tests and parasitological procedures are of the utmost importance for rapid confirmation and notification of a case, thus contributing directly to the control of a focus.
Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology: Orgao Oficial do Colegio Brasileiro de Parasitologia Veterinaria 10/2013; 22(3):424-426. DOI:10.1590/S1984-29612013000300018 · 0.87 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: American visceral leishmaniasis is caused by the protozoan Leishmania infantum. Dogs are the main reservoirs in the domestic transmission cycle. The limited accuracy of diagnostic tests for canine leishmaniasis may contribute to the lack of impact of control measures recommended by the Brazilian Ministry of Health. The objective of this study was to estimate the accuracy of two enzyme-linked immunosorbent assays employing L. major or L. infantum antigens and their reliability between three laboratories of different levels of complexity.
A validation study of ELISA techniques using L. major or L. infantum antigens was conducted. Direct visualization of the parasite in hematoxylin/eosin-stained histopathological sections, immunohistochemistry, and isolation of the parasite in culture.were used as gold standard. An animal that was positive in at least one of the tests was defined as infected with L. infantum. Serum samples collected from 1,425 dogs were analyzed. Samples were separated in three aliquots and tested in three different laboratories. Sensitivity, specificity and the area under de ROC curve were calculated and the reliability was evaluated between the participant laboratories.
The sensitivity was 91.8% and 89.8% for the L. major and L. infantum assays, respectively. The specificity was 83.75% and 82.7% for the L. major and L. infantum assays, respectively. The area under de ROC curve was 0.920 and 0.898 for L. major and L. infantum, respectively. The mean intraclass correlation coefficients between laboratories ranged from 0.890 to 0.948 when L. major was used as antigen, and from 0.818 to 0.879 when L. infantum was used.
ELISA tests using L. major or L. infantum antigens have similar accuracy and reliability. Our results do not support the substitution of the L. major antigen of the ELISA test currently used for the diagnosis of canine visceral leishmaniasis in Brazil.
PLoS ONE 07/2013; 8(7):e69988. DOI:10.1371/journal.pone.0069988 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The accurate diagnosis of canine visceral leishmaniasis (CanL) is essential for visceral leishmaniasis control. To this end, DNA detection on different biological samples has been employed. In this study, we report the use of polymerase chain reaction (PCR) assay on samples such as buffy coat, bone marrow, intact skin and cutaneous ulcers fragments, and lymph node aspirate collected from 430 dogs to determine the suitable biological sample for use in CanL diagnosis. The PCR results were correlated with clinical status and other tests previously performed. Leishmania chagasi DNA was detected in 14.6% (n = 63) of the dogs investigated, regardless of the sample analyzed. Our results showed that symptomatic cases were easily diagnosed when compared to asymptomatic animals; however, the PCR proved to be very useful for Leishmania DNA detection, mainly in lymph node aspirate (41; 9.6%), irrespective of the clinical status of the dog. The finding that the lymph node aspirate produced high positivity rates and the fact that this specimen was obtained by noninvasive methods highlight its use in epidemiological survey by PCR for CanL diagnosis.
[Show abstract][Hide abstract] ABSTRACT: 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.
Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology: Orgao Oficial do Colegio Brasileiro de Parasitologia Veterinaria 03/2013; 22(2). DOI:10.1590/S1984-29612013005000014 · 0.87 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Disseminated intravascular coagulation (DIC) is an acquired disorder characterized by the activation of intravascular coagulation and excessive fibrin formation. It always occurs in association with other clinical conditions, including parasitic diseases. DIC has been described as a unusual complication in human and canine visceral leishmaniasis.
DIC was found in a seven-year-old male mongrel dog naturally infected by Leishmania (Leishmania) chagasi. Haemostasis parameters demonstrated changes in primary and secondary haemostasis and fibrinolysis.
DIC is a unusual condition described in canine visceral leishmaniasis and it seems to be associated with several immunological and pathological mechanisms involved in the disease.
BMC Veterinary Research 03/2013; 9:43. DOI:10.1186/1746-6148-9-43 · 1.78 Impact Factor