Seroprevalence and spatial distribution of canine leishmaniasis in an endemic region in Brazil: how has the situation changed after 10 years?

Abstract The role of cats in the epidemiological cycle of leishmaniasis remains unclear. To better understand the occurrence of leishmaniasis in cats, we studied the frequency of Leishmania in serum samples of 100 cats living in an endemic region for canine and human leishmaniasis by serological, parasitological, and molecular methods. Of the 100 cats, 54 were seropositive for Leishmania antibodies by immunofluorescence antibody test. None of the bone marrow aspirates collected from these cats tested positive for the parasite in culture or upon polymerase chain reaction (PCR) analysis. Biopsy samples of the ears also tested negative for Leishmania upon PCR analysis. These findings may indicate that the region is endemic for canine leishmaniasis and cats are infected by Leishmania; or that cross-reaction with antibodies against other parasites increases the frequency of seropositivity; or that cats respond to Leishmania infection by producing antibodies when few or no parasites are present in bone marrow and tissue samples. Overall, our results suggest that cats can be infected by Leishmania ; however, we failed to demonstrate feline parasitosis. These findings highlight the need to study leishmaniasis in cats, since sandflies feed on cats, these animals may act as a reservoir for the parasite.

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Canine leishmaniasis in an endemic region, Northeastern Brazil: a comparative study with four groups of animals

Parasitology Research ◽

10.1007/s00436-021-07319-0 ◽

2021 ◽

Author(s):

Matheus Resende Oliveira ◽

Manuel Benicio Oliveira Neto ◽

Taynar Lima Bezerra ◽

Weslania Souza Inacio da Silva ◽

Wandklebson Silva da Paz ◽

...

Keyword(s):

Comparative Study ◽

Northeastern Brazil ◽

Canine Leishmaniasis ◽

Endemic Region

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Spatial distribution of triatomine bugs in a Chagas disease endemic region in Brazil

Revista da Sociedade Brasileira de Medicina Tropical ◽

10.1590/0037-8682-0278-2019 ◽

2019 ◽

Vol 52 ◽

Author(s):

Tatiene Rossana Móta Silva ◽

Guilherme Mota Maciel do Rêgo Barros ◽

Thiago Antonio Rodrigues Freire Lima ◽

Alessio Giannelli ◽

Gesika Maria da Silva ◽

...

Keyword(s):

Spatial Distribution ◽

Chagas Disease ◽

Endemic Region ◽

Triatomine Bugs

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Serological and molecular diagnostic tests for canine visceral leishmaniasis in Brazilian endemic area: one out of five seronegative dogs are infected

Epidemiology and Infection ◽

10.1017/s0950268817001443 ◽

2017 ◽

Vol 145 (12) ◽

pp. 2436-2444 ◽

Cited By ~ 16

Author(s):

E. G. LOPES ◽

A. P. SEVÁ ◽

F. FERREIRA ◽

C. M. NUNES ◽

L. B. KEID ◽

...

Keyword(s):

Lymph Node ◽

Visceral Leishmaniasis ◽

Rapid Test ◽

Canine Leishmaniasis ◽

Molecular Diagnostic ◽

Endemic Region ◽

Serological Tests ◽

Endemic Areas ◽

The Impact ◽

Immunoenzymatic Assay

SUMMARYEuthanasia of infected dogs is one of the measures adopted in Brazil to control visceral leishmaniasis (VL) in endemic areas. To detect infected dogs, animals are screened with the rapid test DPP® Visceral Canine Leishmaniasis for detection of antibodies against K26/K39 fusion antigens of amastigotes (DPP). DPP-positives are confirmed with an immunoenzymatic assay probing soluble antigens of promastigotes (ELISA), while DPP-negatives are considered free of infection. Here, 975 dogs from an endemic region were surveyed by using DPP, ELISA and real-time PCR (qPCR) for the diagnosis of VL. When DPP-negative dogs were tested by qPCR applied in blood and lymph node aspirates, 174/887 (19·6%) were positive in at least one sample. In a second sampling using 115 cases, the DPP-negative dogs were tested by qPCR in blood, lymph node and conjunctival swab samples, and 36/79 (45·6%) were positive in at least one sample. Low-to-moderate pairwise agreement was observed between all possible pair of tests. In conclusion, the official diagnosis of VL in dogs in Brazilian endemic areas failed to accuse an expressive number of infected animals and the impact of the low accuracy of serological tests in the success of euthanasia-based measure for VL control need to be assessed.

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Spatial distribution of canine Leishmania infantum infection in a municipality with endemic human leishmaniasis in Eastern Bahia, Brazil

Revista Brasileira de Parasitologia Veterinária ◽

10.1590/s1984-29612021034 ◽

2021 ◽

Vol 30 (2) ◽

Author(s):

Bruno Milen Varjão ◽

Flaviane Alves de Pinho ◽

Manuela da Silva Solcà ◽

Ricardo Silvestre ◽

Mahyumi Fujimori ◽

...

Keyword(s):

Spatial Distribution ◽

Visceral Leishmaniasis ◽

Epidemiological Study ◽

Leishmania Infantum ◽

Clinical Manifestations ◽

Epidemiological Data ◽

Canine Leishmaniasis ◽

Rural Districts ◽

Animal Infection ◽

Human Leishmaniasis

Abstract Efforts to control a zoonotic disease such as visceral leishmaniasis (VL) caused by Leishmania infantum can be successful if they rely on comprehensive data on animal infection. In Bahia state, Brazil, human VL is endemic, yet some areas have no epidemiological data on canine L. infantum infection and canine leishmaniasis (CanL) to date. We aimed to perform an epidemiological study describing the spatial distribution and characterizing canine L. infantum infection in two districts of the municipality of Muritiba, where human cases have occurred. Brazilian official serodiagnostic protocol (ELISA and immunochromatographic tests), PCR and clinical examination were performed in 351 owned dogs. A seroprevalence of 15.7% (55/351) was found, and L. infantum identified in 88.8% (32/36) of PCR tested samples. Spatial distribution of positive dogs indicated infection in both urban and rural districts. There was no association between seropositivity and sex or breed, but dogs older than 2 years were 3.8 times more likely to be seropositive (95% CI 1.57 - 9.18) than younger dogs. Among seropositive dogs, 80% (44/55) had clinical manifestations of CanL: 75% (33/44) presented dermatopathy, 50% (22/44) emaciation, and 29.5% (13/44) ophthalmopathy. This is the first report on canine seroprevalence and natural L. infantum infection in Muritiba, Bahia.

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Feline Leishmania infection in a canine leishmaniasis endemic region, Portugal

Veterinary Parasitology ◽

10.1016/j.vetpar.2010.08.030 ◽

2010 ◽

Vol 174 (3-4) ◽

pp. 336-340 ◽

Cited By ~ 56

Author(s):

C. Maia ◽

J. Gomes ◽

J. Cristóvão ◽

M. Nunes ◽

A. Martins ◽

...

Keyword(s):

Canine Leishmaniasis ◽

Leishmania Infection ◽

Endemic Region

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Lithography below 100 nm

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100074367 ◽

1983 ◽

Vol 41 ◽

pp. 96-99

Author(s):

L. D. Jackel

Keyword(s):

Spatial Distribution ◽

Electron Beam ◽

Electron Scattering ◽

Electron Beam Lithography ◽

Substrate Material ◽

Local Electron ◽

Electron Dose ◽

Positive Resist ◽

Exposure Process

Most production electron beam lithography systems can pattern minimum features a few tenths of a micron across. Linewidth in these systems is usually limited by the quality of the exposing beam and by electron scattering in the resist and substrate. By using a smaller spot along with exposure techniques that minimize scattering and its effects, laboratory e-beam lithography systems can now make features hundredths of a micron wide on standard substrate material. This talk will outline sane of these high- resolution e-beam lithography techniques.We first consider parameters of the exposure process that limit resolution in organic resists. For concreteness suppose that we have a “positive” resist in which exposing electrons break bonds in the resist molecules thus increasing the exposed resist's solubility in a developer. Ihe attainable resolution is obviously limited by the overall width of the exposing beam, but the spatial distribution of the beam intensity, the beam “profile” , also contributes to the resolution. Depending on the local electron dose, more or less resist bonds are broken resulting in slower or faster dissolution in the developer.

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SEM evaluation of the TEM cold-stage double-film specimen

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100111471 ◽

1984 ◽

Vol 42 ◽

pp. 272-273

Author(s):

Jayesh Bellare

Keyword(s):

Spatial Distribution ◽

Sample Preparation ◽

Sample Thickness ◽

Specimen Preparation ◽

Preparation Technique ◽

Liquid Sample ◽

Thin Specimen ◽

Sample Preparation Technique ◽

Cold Stage ◽

Film Specimen

Seeing is believing, but only after the sample preparation technique has received a systematic study and a full record is made of the treatment the sample gets.For microstructured liquids and suspensions, fast-freeze thermal fixation and cold-stage microscopy is perhaps the least artifact-laden technique. In the double-film specimen preparation technique, a layer of liquid sample is trapped between 100- and 400-mesh polymer (polyimide, PI) coated grids. Blotting against filter paper drains excess liquid and provides a thin specimen, which is fast-frozen by plunging into liquid nitrogen. This frozen sandwich (Fig. 1) is mounted in a cooling holder and viewed in TEM.Though extremely promising for visualization of liquid microstructures, this double-film technique suffers from a) ireproducibility and nonuniformity of sample thickness, b) low yield of imageable grid squares and c) nonuniform spatial distribution of particulates, which results in fewer being imaged.

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Macroprobe Mode for the Study of Segregation in Steels

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134909 ◽

1990 ◽

Vol 48 (2) ◽

pp. 260-261

Author(s):

Auclair Gilles ◽

Benoit Danièle

Keyword(s):

Mechanical Properties ◽

Spatial Distribution ◽

High Performance ◽

Volume Fraction ◽

Sheet Steel ◽

Acquisition Time ◽

Chemical Information ◽

X Ray ◽

Accurate Quantitative Analysis ◽

Optical Micrographs

During these last 10 years, high performance correction procedures have been developed for classical EPMA, and it is nowadays possible to obtain accurate quantitative analysis even for soft X-ray radiations. It is also possible to perform EPMA by adapting this accurate quantitative procedures to unusual applications such as the measurement of the segregation on wide areas in as-cast and sheet steel products.The main objection for analysis of segregation in steel by means of a line-scan mode is that it requires a very heavy sampling plan to make sure that the most significant points are analyzed. Moreover only local chemical information is obtained whereas mechanical properties are also dependant on the volume fraction and the spatial distribution of highly segregated zones. For these reasons we have chosen to systematically acquire X-ray calibrated mappings which give pictures similar to optical micrographs. Although mapping requires lengthy acquisition time there is a corresponding increase in the information given by image anlysis.

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Ultrastructural analysis of the spatial distribution of MRNA

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100123167 ◽

1992 ◽

Vol 50 (1) ◽

pp. 552-553

Author(s):

Gary Bassell ◽

Robert H. Singer

Keyword(s):

Electron Microscopy ◽

Spatial Distribution ◽

In Situ Hybridization ◽

High Resolution ◽

Nucleic Acids ◽

Colloidal Gold ◽

Dna Probe ◽

Nucleotide Analogs ◽

Gold Particles

We have been investigating the spatial distribution of nucleic acids intracellularly using in situ hybridization. The use of non-isotopic nucleotide analogs incorporated into the DNA probe allows the detection of the probe at its site of hybridization within the cell. This approach therefore is compatible with the high resolution available by electron microscopy. Biotinated or digoxigenated probe can be detected by antibodies conjugated to colloidal gold. Because mRNA serves as a template for the probe fragments, the colloidal gold particles are detected as arrays which allow it to be unequivocally distinguished from background.

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