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BACKGROUND Studies aimed at validating canine visceral leishmaniasis diagnostic tests present heterogeneous results regarding test accuracy, partly due to divergences in reference standards used and different infection evolution periods in animals. OBJECTIVE This study aimed to evaluate the accuracy of the rapid test-dual path platform (TR-DPP) (Biomanguinhos®), EIE-Leishmaniose-Visceral-Canina-Biomanguinhos (EIE-LVC) (Biomanguinhos®), enzyme-linked immunosorbent assay (ELISA) rK39 (in-house), and the direct agglutination test (DAT-Canis) against a reference standard comprising parasitological and molecular techniques. METHODS A phase II/III validation study was carried out in sample sera from 123 predominantly asymptomatic dogs living in an area endemic for visceral leishmaniasis. FINDINGS Sixty-nine (56.1%) animals were considered infected according to the reference standard. For each test, the sensitivity and specificity, respectively, were as follows: TR-DPP, 21.74% [confidence interval (CI)95% 13.64% to 32.82%] and 92.59% (CI95% 82.45% to 97.08%); EIE-LVC, 11.59% (CI95% 5.9% to 21.25%) and 90.74% (CI95% 80.09% to 95.98%); ELISA rK39, 37.68% (CI95% 27.18% to 49.48%) and 83.33% (CI95% 71.26% to 90.98%); and DAT-Canis, 18.84% (CI95% 11.35% to 29.61%) and 96.30% (CI95% 87.46% to 98.98%). CONCLUSION We concluded that improving the sensitivity of serum testing for diagnosing asymptomatic dogs must constitute a priority in the process of developing new diagnostic tests to be used in the visceral leishmaniasis control program in Brazil.

This report describes the stege I/II development of a new direct agglutination test (DAT) for the diagnosis of canine visceral leishmaniasis (CVL) using freeze-dried antigen produced Coomassie blue-stained Leishmania (Leishmania) infantum promastigotes. In stage I, 16 canine serum samples, collected from eight dogs carrying CVL and eight healthy dogs, were assessed with the DAT using 2-mercaptoethanol (2-ME), N-acetyl-cysteine (NAC), kaolin or NAC plus urea (NAC+U) to improve the assay conditions. Stage II assessed the diagnostic accuracy with 100 serum samples collected from dogs with symptomatic CVL and clinically healthy dogs, comparing the four different sample diluents. The CVL-DAT prototype kit showed equivalent performances when 2-ME, NAC or NAC+U were used: 97.1% sensitivity (CI: 83-99.8%), 97% specificity (CI: 88.5-99.5%) and a 97% diagnostic accuracy (CI: 90.8-99.2). With kaolin, a 94.1% sensitivity (CI: 79-99%), 97% specificity (CI: 88.5-99.5%) and 96% diagnostic accuracy were observed (CI: 89.5-98.7), with no statistically significant differences among the four reagents (p=1.0). The NAC plus urea in sample diluent decreased non-specific agglutination, promoted a better defined sharp-edged blue spot and was thus chosen as a component for the new DAT prototype to diagnose canine VL, designated DAT-Canis.

The aim of the present study was to estimate the financial costs of the incorporation and/or replacement of diagnostic tests for human visceral leishmaniasis (VL) in Brazil. The analysis was conducted from the perspective of the Brazilian Unified National Health System (SUS) over a period of three years. Six diagnostic tests were evaluated: the indirect immunofluorescence antibody test (IFAT), the IT LEISH rapid test, the parasitological examination of bone marrow aspirate, the direct agglutination test (DAT-LPC) standardized in the Clinical Research Laboratory, René Rachou Institute of the Oswaldo Cruz Foundation, the Kalazar Detect rapid test, and polymerase chain reaction (PCR). The assumptions used were the number of suspected cases of VL reported to the Brazilian Ministry of Health in 2014 and the direct cost of diagnostic tests. The costs to diagnose suspected cases of VL over three years using the IFAT and the DAT-LPC were estimated at USD 280,979.91 and USD 121,371.48, respectively. The analysis indicated that compared with the use of the IFAT, the incorporation of the DAT-LPC into the SUS would result in savings of USD 159,608.43. With regard to the budgetary impact of rapid tests, the use of IT LEISH resulted in savings of USD 21.708,72 over three years. Compared with a parasitological examination, diagnosis using PCR resulted in savings of USD 3,125,068.92 over three years. In this study, the replacement of the IFAT with the DAT-LPC proved financially advantageous. In addition, the replacement of the Kalazar Detect rapid test with the IT LEISH in 2015 was economically valuable, and the replacement of parasitological examination with PCR was indicated.

A susceptible-infective-recovered (SIR) epidemiological model based on probabilistic cellular automaton (PCA) is employed for simulating the temporal evolution of the registered cases of chickenpox in Arizona, USA, between 1994 and 2004. At each time step, every individual is in one of the states S, I, or R. The parameters of this model are the probabilities of each individual (each cell forming the PCA lattice) passing from a state to another state. Here, the values of these probabilities are identified by using a genetic algorithm. If nonrealistic values are allowed to the parameters, the predictions present better agreement with the historical series than if they are forced to present realistic values. A discussion about how the size of the PCA lattice affects the quality of the model predictions is presented.

Pleural and peritoneal milky spots (MS) are small morphofunctional structures representing subsidiary foci of coelom-associated lymphomyeloid tissue (CALT). In this paper we studied the cellular composition of CALT in normal and Schistosoma mansoni-infected mice. In the healthy mouse, CALT is mainly composed of IgM (+) B cells and presents lower numbers of CD23 and CD45R (B220) B2 lymphocytes. When activated by the infection, it may show pronounced lymphocytosis, plasmocytogenesis (IgMIgGIgAIgG2aIgG1) and myelomonocytosis. The lymphocytes were mainly of the B1 type (double positive CD5/IgM), with smaller number of T cells (TCR alpha beta (+), TCR gamma delta (+), CD3 (+) and CD5 (+)) and conventional B2 cells (B220 (+), CD23 (+)). The myeloid compartment was composed of immature and mature cells of monocyte/macrophage, eosinophil, neutrophil and megakaryocytic lineages, especially in the omental milky spots. CALT is also a favorable microenvironment for LFA-1 (+) mast cells. Thus, CALT appears to be a mixed lymphoid organ, with secondary and/or primary lymphoid organ functions, being an important site of B1 cell generation, plasma cell maturation and extramedullar hematopoiesis. CALT operates as an interface between blood and lymphatic circulation and coelomic cavities, because locally or externally produced cells have easy and ready access to the pleural and peritoneal cavities. Furthermore, MS cells can escape into blood and lymphatic vessels, providing lymphocytes to other lymphoid organs and to the mucosa-associated lymphoid tissue.

1. The plasma concentrations of low- and high-density lipoproteins (LDL and HDL) were significantly reduced in Brazilian patients with compensated hepatosplenic schistosomiasis mansoni (SM) when compared with healthy individuals, but very low-density lipoprotein (VLDL) levels were unchanged. 2. All three classes of lipoproteins isolated from SM plasma had an increased content of triacylglycerol and unesterified cholesterol and decreased cholesteryl ester and phospholipid. 3. The individual phospholipid composition of patient VLDL, LDL, HDL was also altered; the amount of phosphatidylcholine was increased and that of lysophosphatidylcholine decreased. 4. The saturated and monounsaturated fatty acyl content of cholesteryl esters in patient lipoproteins was also significantly increased, and diunsaturated and polyunsaturated fatty acyl content was decreased. 5. When isolated lipoproteins were examined as negatively stained preparations by electron microscopy, the morphology of SM patient LDL was normal but the HDL fraction was abnormal and showed marked heterogeneity of size with the presence of occasional discoidal particles which resembled "nascent" HDL.