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1.
PLoS One ; 15(7): e0236127, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32692783

RESUMO

Visceral leishmaniasis (VL) is an important zoonosis in Brazil. Dogs are considered the main domestic reservoirs of the disease in the country; hence, control measures are focused on these reservoirs. Despite efforts to prevent and control VL, important reductions in disease prevalence and incidence have not been identified, stimulating the development and application of new strategies. The choice and implementation of new control strategies can benefit from the application of mathematical models that allow the simulation of different strategies in different scenarios. Selecting the best strategy to be implemented is also supported by cost-effectiveness studies. Here we used the results of a mathematical model in which scenarios, including isolated use of the vaccine and insecticide-impregnated collar (IIC), both at different coverage rates, were simulated to conduct a cost-effectiveness study. The costs were calculated for each scenario considering a simulation period of four years. Collar application in both infected and non-infected animals was the most cost-effective strategy. For example, to reduce the prevalence in humans and dogs by approximately 70%, the costs ranged from $250,000 and $550,000 for the IICs and vaccination, respectively. Even in the scenario with 40% loss/replacement of IICs, this measure was more advantageous in terms of cost-effectiveness than vaccination. If the vaccine were applied with culling of seropositive tested dogs, then the measure became more effective with a reduced cost compared with the vaccine alone. The use of the three first consecutive vaccine doses had the greatest impact on the cost of the vaccination strategy. The advantage of using IICs is that there is no need for a prior diagnosis, unlike vaccination, reducing costs and facilitating implementation. The present study aims to contribute to strategies to reduce hosts infected with VL by reducing public expenditure.


Assuntos
Doenças do Cão/economia , Doenças do Cão/prevenção & controle , Leishmania donovani/efeitos dos fármacos , Leishmaniose Visceral/economia , Leishmaniose Visceral/prevenção & controle , Vacinação/economia , Vacinação/veterinária , Animais , Brasil/epidemiologia , Doenças do Cão/parasitologia , Doenças do Cão/transmissão , Cães , Leishmania donovani/isolamento & purificação , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/veterinária , Prevalência
2.
PLoS One ; 15(7): e0235920, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32678864

RESUMO

Nationwide disease surveillance at a high spatial resolution is desired for many infectious diseases, including Visceral Leishmaniasis. Statistical and mathematical models using data collected from surveillance activities often use a spatial resolution and scale either constrained by data availability or chosen arbitrarily. Sensitivity of model results to the choice of spatial resolution and scale is not, however, frequently evaluated. This study aims to determine if the choice of spatial resolution and scale are likely to impact statistical and mathematical analyses. Visceral Leishmaniasis in Brazil is used as a case study. Probabilistic characteristics of disease incidence, representing a likely outcome in a model, are compared across spatial resolutions and scales. Best fitting distributions were fit to annual incidence from 2004 to 2014 by municipality and by state. Best fits were defined as the distribution family and parameterization minimizing the sum of absolute error, evaluated through a simulated annealing algorithm. Gamma and Poisson distributions provided best fits for incidence, both among individual states and nationwide. Comparisons of distributions using Kullback-Leibler divergence shows that incidence by state and by municipality do not follow distributions that provide equivalent information. Few states with Gamma distributed incidence follow a distribution closely resembling that for national incidence. These results demonstrate empirically how choice of spatial resolution and scale can impact mathematical and statistical models.


Assuntos
Monitoramento Epidemiológico , Leishmaniose Visceral/epidemiologia , Brasil/epidemiologia , Humanos , Incidência , Análise Espacial
3.
PLoS Negl Trop Dis ; 14(7): e0008468, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32614857

RESUMO

Human visceral leishmaniasis (VL) vaccines are currently under development and there is a need to understand their potential impact on population wide VL incidence. We implement four characteristics from different human VL vaccine candidates into two published VL transmission model variants to estimate the potential impact of these vaccine characteristics on population-wide anthroponotic VL incidence on the Indian subcontinent (ISC). The vaccines that are simulated in this study 1) reduce the infectiousness of infected individuals towards sand flies, 2) reduce risk of developing symptoms after infection, 3) reduce the risk of developing post-kala-azar dermal leishmaniasis (PKDL), or 4) lead to the development of transient immunity. We also compare and combine a vaccine strategy with current interventions to identify their potential role in elimination of VL as a public health problem. We show that the first two simulated vaccine characteristics can greatly reduce VL incidence. For these vaccines, an approximate 60% vaccine efficacy would lead to achieving the ISC elimination target (<1 VL case per 10,000 population per year) within 10 years' time in a moderately endemic setting when vaccinating 100% of the population. Vaccinating VL cases to prevent the development of PKDL is a promising tool to sustain the low incidence elimination target after regular interventions are halted. Vaccines triggering the development of transient immunity protecting against infection lead to the biggest reduction in VL incidence, but booster doses are required to achieve perduring impact. Even though vaccines are not yet available for implementation, their development should be pursued as their potential impact on transmission can be substantial, both in decreasing incidence at the population level as well as in sustaining the ISC elimination target when other interventions are halted.


Assuntos
Vacinas contra Leishmaniose/imunologia , Leishmaniose Cutânea/prevenção & controle , Leishmaniose Visceral/epidemiologia , Humanos , Incidência , Índia/epidemiologia , Leishmaniose Visceral/prevenção & controle , Saúde Pública
4.
PLoS Negl Trop Dis ; 14(7): e0008465, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32706789

RESUMO

BACKGROUND: Leishmaniasis is one of the most important vector-borne diseases and it represents a serious world health problem affecting millions of people. High levels of Leishmania infections, affecting both humans and animals, are recognized among Italian regions. Among these, Sicily has one of the highest prevalence of Leishmania infection. METHODOLOGY/PRINCIPAL FINDINGS: Seventy-eight Leishmania strains isolated from human and animal samples across Sicily, were analyzed for the polymorphic k26-gene and genotypes were assigned according to the size of the PCR products. A multilocus microsatellite typing (MLMT) approach based on the analysis of 11 independent loci was used to investigate populations structure and genetic diversity of the isolated strains. Six L. infantum reference strains were included in the analysis for comparison. Bayesian clustering analysis of microsatellite data showed that all the isolated strains clustered in two genetically distinct populations, corresponding to human and canine isolates respectively. A further subdivision was observed between the two main groups, giving a good correlation between human strains and their geographic origin, conversely canine population showed a great genetic variability diffused in the territory. CONCLUSIONS/SIGNIFICANCE: Among the 78 Leishmania isolates, K26 analysis detected 71 samples (91%) as MON-1 zymodeme, confirming it as the predominant strain in Mediterranean area and 7 human samples (9%) as non-MON-1. MLMT gives important insights into the epidemiology of leishmaniases and allows characterization of different strains to a higher resolution than possible with zymodeme typing. Two main populations presented a strong correlation respect to the different hosts, exhibiting a co-circulation of two distinct populations of L. infantum. The population found in infected humans exhibited a correlation with geographic origin. These clusters could represent a geographically restricted population of strains with the same or related genotypes. This study can contribute to an understanding of Leishmania epidemiology, including the spread of reservoirs and sand fly vectors in the different foci of infection, characterizing parasites within the different hosts.


Assuntos
Doenças do Cão/parasitologia , Leishmania infantum/genética , Leishmaniose Visceral/veterinária , Animais , Doenças do Cão/epidemiologia , Cães , Humanos , Itália/epidemiologia , Leishmania infantum/classificação , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/parasitologia
5.
PLoS Negl Trop Dis ; 14(7): e0008422, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32644989

RESUMO

BACKGROUND: The elimination programme for visceral leishmaniasis (VL) in India has seen great progress, with total cases decreasing by over 80% since 2010 and many blocks now reporting zero cases from year to year. Prompt diagnosis and treatment is critical to continue progress and avoid epidemics in the increasingly susceptible population. Short-term forecasts could be used to highlight anomalies in incidence and support health service logistics. The model which best fits the data is not necessarily most useful for prediction, yet little empirical work has been done to investigate the balance between fit and predictive performance. METHODOLOGY/PRINCIPAL FINDINGS: We developed statistical models of monthly VL case counts at block level. By evaluating a set of randomly-generated models, we found that fit and one-month-ahead prediction were strongly correlated and that rolling updates to model parameters as data accrued were not crucial for accurate prediction. The final model incorporated auto-regression over four months, spatial correlation between neighbouring blocks, and seasonality. Ninety-four percent of 10-90% prediction intervals from this model captured the observed count during a 24-month test period. Comparison of one-, three- and four-month-ahead predictions from the final model fit demonstrated that a longer time horizon yielded only a small sacrifice in predictive power for the vast majority of blocks. CONCLUSIONS/SIGNIFICANCE: The model developed is informed by routinely-collected surveillance data as it accumulates, and predictions are sufficiently accurate and precise to be useful. Such forecasts could, for example, be used to guide stock requirements for rapid diagnostic tests and drugs. More comprehensive data on factors thought to influence geographic variation in VL burden could be incorporated, and might better explain the heterogeneity between blocks and improve uniformity of predictive performance. Integration of the approach in the management of the VL programme would be an important step to ensuring continued successful control.


Assuntos
Leishmaniose Visceral/epidemiologia , Modelos Estatísticos , Erradicação de Doenças , Humanos , Índia/epidemiologia , Leishmaniose Visceral/prevenção & controle , Análise Espaço-Temporal
6.
BMC Infect Dis ; 20(1): 401, 2020 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-32503461

RESUMO

BACKGROUND: Visceral leishmaniasis is an important but neglected disease that is spreading and is highly lethal when left untreated. This study sought to measure the Leishmania infantum seroprevalence in dogs, the coverage of its control activities (identification of the canine reservoir by serological survey, dog culling and insecticide spraying) and to evaluate its relationship with the occurrence of the disease in humans in the municipalities of Araçatuba and Birigui, state of São Paulo, Brazil. METHODS: Information from 2006 to 2015 was georeferenced for each municipality and modeling was performed for the two municipalities together. To do this, latent Gaussian Bayesian models with the incorporation of a spatio-temporal structure and Poisson distribution were used. The Besag-York-Mollie models were applied for random spatial effects, as also were autoregressive models of order 1 for random temporal effects. The modeling was performed using the INLA (Integrated Nested Laplace Approximations) deterministic approach, considering both the numbers of cases as well as the coverage paired year by year and lagged at one and two years. RESULTS: Control activity coverage was observed to be generally low. The behavior of the temporal tendency in the human disease presented distinct patterns in the two municipalities, however, in both the tendency was to decline. The canine serological survey presented as a protective factor only in the two-year lag model. CONCLUSIONS: The canine serological coverage, even at low intensity, carried out jointly with the culling of the positive dogs, suggested a decreasing effect on the occurrence of the disease in humans, whose effects would be seen two years after it was carried out.


Assuntos
Formigas/parasitologia , Doenças do Cão/diagnóstico , Doenças do Cão/patologia , Leishmaniose Visceral/patologia , Animais , Teorema de Bayes , Brasil/epidemiologia , Doenças do Cão/epidemiologia , Cães , Humanos , Leishmania infantum/isolamento & purificação , Leishmaniose Visceral/epidemiologia , Distribuição de Poisson , Fatores de Risco , Estudos Soroepidemiológicos
7.
PLoS Negl Trop Dis ; 14(6): e0008272, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32555598

RESUMO

INTRODUCTION: Presence of asymptomatic individuals in endemic areas is common. The possible biomarkers in asymptomatic individuals once they get exposed to infection as well as following conversion to symptomatic disease are yet to be identified.We identified asymptomatic Visceral leishmaniasis (VL) infection amongst rK39+sorted direct agglutination test positive (DAT+) endemic healthy population and confirmed it by quantitative PCR(qPCR).The immunological determinants such as Adenosine deaminase (ADA), Interferon gamma (IFN-γ), Tumour Necrosis Factor alpha (TNF-α) and Interleukin 10 (IL-10)were examined to predict probable biomarkers for conversion to symptomatic VL. METHODS: Sample size was 5794 healthy individuals from VL endemic region. Antibody tests(DAT &rK39) were performed and later a qPCR assay was employed using kDNA specific primers and probes. Immunological biomarkers examined were ADA level by ADA-MTP kit and quantitative cytokines(IFN-γ, IL-10 and TNF-α) by ELISA. RESULTS: 120 asymptomatic individuals of 308 rK39 sero-positives were DAT positive comprising of 56 with previous history and 64 with no history of VL. RT-PCR confirmed asymptomatic VL in 42 sero-positives. These were followed up through repeated qPCR and evaluation of immunological determinants. We observed10 symptomatic cases converted from a total of 42 asymptomatic individuals identified at base-line. The level of ADA, IL-10 and IFN-γ remained consistently high in asymptomatic cases and amongst these, ADA and IL-10 but not IFN-γ remained higher at the development of clinical symptoms into active VL. On the contrary, there was no significant change in the mean concentration of TNF-α at both stages of the disease. DISCUSSION: We surmise from our data that considerable proportion of asymptomatic cases can be a reservoir and may play a crucial role in transmission of visceral leishmaniasis in endemic areas. The data also suggests that ADA and IL-10 can serve as a potential biomarker during the conversion of asymptomatic into symptomatic VL.


Assuntos
Anticorpos Antiprotozoários/sangue , Citocinas/sangue , Leishmaniose Visceral/epidemiologia , Adolescente , Adulto , Idoso , Testes de Aglutinação , Infecções Assintomáticas/epidemiologia , Biomarcadores/sangue , Criança , Progressão da Doença , Doenças Endêmicas , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Índia/epidemiologia , Leishmania donovani , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/imunologia , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase em Tempo Real , Soroconversão , Adulto Jovem
8.
Ann Parasitol ; 66(2): 135-141, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32530590

RESUMO

There is an increasing concern about the co-infection of visceral leishmaniosis (VL) with human immunodeficiency virus (HIV) and/or viral hepatitis B/C. The aim of this study was to determine the prevalence of HIV and viral hepatitis co-infections among VL patients in a hyperendemic area in Eastern Sudan and to assess antibody levels in co-infected patients. This is a retrospective study where the sera of confirmed VL cases and non-VL individuals were analysed. The sera were screened for co-infections using immunochromatographic tests and ELISA for anti-HIV 1+2 antibodies, hepatitis B surface antigen (HBsAg), and anti-hepatitis C virus (HCV). Anti-Leishmania donovani antibodies in the sera of VL alone were assessed and compared to the sera of co-infected patients. Of the 100 screened VL sera, 6 (6%), 0 (0%), and 1 (1%) were positive for HBsAg, anti-HCV, and anti-HIV, respectively. These values were 5 (5%), 0 (0%), and 1 (1%) in the control group. Of note, the HCV screening test (Biorex, UK) showed positive reactivity in 32 (32%) and 17 (17%) sera of VL and control groups, respectively. All reactive sera tested negative in HCV ELISA. Of the 93 VL sera, 75 (80.6%) had strong DAT titers (1:˃102400), 2 (2.1%) demonstrated the lowest DAT titers (1:≤800), and 5 (5.4%) had marginal DAT titers (1:1600). Interestingly, the VL/HIV co-infected serum had a negative antibody titer (1:1600). Of the 6 VL/HBV co-infected sera, 1 (16.7%) and 5 (83.3%) demonstrated moderate (1:12800­1:51600) and strong (1:≥102400) DAT titers, respectively. The strong DAT titers observed in the VL/HBV co-infected sera were comparable to the DAT titers of the VL sera. The VL co-infection with HIV and hepatitis B/C is low in endemic areas in Eastern Sudan but may create a diagnostic difficulty. VL/HIV co-infected patients can have low Leishmania antibodies, thus alternative methodologies (e.g., antigen tests) may help the diagnosis.


Assuntos
Infecções por HIV , Hepatite Viral Humana , Leishmaniose Visceral , Anticorpos/sangue , Infecções por HIV/sangue , Infecções por HIV/complicações , Infecções por HIV/epidemiologia , Hepatite Viral Humana/sangue , Hepatite Viral Humana/complicações , Hepatite Viral Humana/epidemiologia , Humanos , Leishmaniose Visceral/complicações , Leishmaniose Visceral/epidemiologia , Prevalência , Estudos Retrospectivos , Estudos Soroepidemiológicos , Sudão/epidemiologia
9.
Ann Parasitol ; 66(2): 143-156, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32531102

RESUMO

Recently, Leishmania infantum has increasingly been detected in stray cats in endemic regions of the world. Cats have been considered playing a role in the epidemiology of visceral leishmaniosis, an endemic zoonosis in Iran. The studies concerning feline leishmaniosis (FeL) allow the hypothesis that cats can be considered as potential reservoirs. The investigations on Leishmania infection in cats are very few in Iran and therefore we aimed to assess the L. infantum infection in stray cats and its possible role in transmission of the disease to human by direct agglutination test (DAT), ELISA, nested-PCR and confirmation via sequencing and phylogenetic analysis in Fars province, Iran. Whole blood samples were obtained from 174 stray cats. Anti-Leishmania antibodies were detected in the sera using DAT and ELISA. DNA was extracted from the buffy coat of each subject and PCR amplified, targeting Leishmania kDNA gene. PCR results were confirmed by sequence analysis. Prevalence of clinical signs in positive cats was 19.0%. Anti-Leishmania antibodies with different titers were detected in 48 (27.59%) and leishmanial DNA in 36 (20.69%) of the cats. The sequencing of PCR-positive cats revealed the parasite as L. infantum. A high seroprevalence of L. infantum was revealed, with higher levels in males, adult cats, and those living in rural districts and southern zones. Despite the reservoir task of cats in nature is still ambiguous, the high serological and molecular detection of L. infantum in stray cats indicates that cats are regularly bitten by infected sand flies in Fars province, southern Iran, and may have a potential reservoir role in the maintenance of L. infantum in the endemic areas of zoonotic visceral leishmaniosis in Iran. Anyway, Leishmania infection must be appraised in the differential diagnosis of cutaneous or systemic clinical signs in cats.


Assuntos
Anticorpos Antiprotozoários/sangue , Leishmania infantum , Leishmaniose Visceral/veterinária , Animais , Gatos , DNA de Protozoário/sangue , Feminino , Humanos , Irã (Geográfico)/epidemiologia , Leishmaniose Visceral/sangue , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/transmissão , Masculino , Filogenia , Reação em Cadeia da Polimerase , Prevalência , Estudos Soroepidemiológicos
10.
Rev Bras Parasitol Vet ; 29(2): e001120, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32490894

RESUMO

This study aimed to determine the seroprevalence, factors associated with seropositivity to Leishmania infection in dogs and spatial analysis in six municipalities in the semiarid region of Pernambuco, Brazil. Blood samples were collected from 462 dogs, 77 in each municipality, and used for serological analysis [dual path platform (DPP®) and enzyme-linked immunosorbent assay (ELISA)]. Clinical signs of dogs were evaluated and associated factors for Leishmania infection were analyzed using robust Poisson regression model. A seroprevalence of 42.8% (198/462, IC: 95% = 38.6%-47.6%) was detected in dogs that tested positive in both tests, ranging from 29.8% to 55.8%, with higher prevalence in the municipality of Cabrobó (55.8%; P = 0.006). About 67% (132/198) of the seropositive dogs showed one or more clinical signs suggestive of canine leishmaniasis (CanL), such as lymphadenomegaly, skin lesions and conjunctivitis, which were associated with seropositivity. High seroprevalence levels were identified in urban and rural areas in all the municipalities, and the buffer for sand flies around cases covered almost these entire areas. Spatial analysis revealed a significant cluster, showing a relative risk of 1.88 in the urban area of Cabrobó. The higher density of seropositive dogs in urban areas indicates the need effective control measures against CanL to prevent the emergence of canine and human diseases.


Assuntos
Anticorpos Antiprotozoários/sangue , Doenças do Cão/epidemiologia , Leishmania infantum/imunologia , Leishmaniose Visceral/veterinária , Animais , Brasil/epidemiologia , Doenças do Cão/diagnóstico , Cães , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/epidemiologia , Masculino , Prevalência , Fatores de Risco , Estudos Soroepidemiológicos , Análise Espacial
11.
Rev Soc Bras Med Trop ; 53: e20190525, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32428174

RESUMO

INTRODUCTION: Canine visceral leishmaniasis (CVL) is a public health problem, and its prevalence is associated with the coexistence of vectors and reservoirs. CVL is a protozoonosis caused by Leishmania infantum that is endemic in the southeast region of Brazil. Thus, vector and canine reservoir control strategies are needed to reduce its burden. This study aimed to verify the CVL seroprevalence and epidemiology in a municipality in Southeast Brazil to initiate disease control strategies. METHODS: A total of 833 dogs were subjected to Dual Path Platform (DPP) testing and enzyme-linked immunosorbent assays. For seropositive dogs, epidemiological aspects were investigated using a questionnaire and a global position system. The data were submitted to simple logistic regression, kernel estimation, and Bernoulli spatial scan statistical analysis. RESULTS: The overall CVL-confirmed seroprevalence was 16.08%. The 28.93% in the DPP screening test was associated with dogs maintained in backyards with trees, shade, animal and/or bird feces, and contact with other dogs and cats, with sick dogs showing the highest chances of infection (odds ratio, 2.6; 95% confidence interval, 2.38-1.98), especially in residences with elderly people. A spatial analysis identified two hotspot regions and detected two clusters in the study area. CONCLUSIONS: Our results demonstrated that residences with elderly people and the presence of trees, shade, feces, and pet dogs and cats increased an individual's risk of developing CVL. The major regions where preventive strategies for leishmaniasis were to be initiated in the endemic area were identified in two clusters.


Assuntos
Doenças do Cão/epidemiologia , Leishmaniose Visceral/veterinária , Animais , Anticorpos Antiprotozoários/sangue , Brasil/epidemiologia , Gatos , Doenças do Cão/diagnóstico , Cães , Doenças Endêmicas , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Leishmania infantum/imunologia , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/epidemiologia , Masculino , Prevalência , Estudos Soroepidemiológicos , Análise Espacial
12.
Rev Bras Parasitol Vet ; 29(2): e016919, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32428183

RESUMO

Dogs have been implicated as main reservoirs for visceral leishmaniasis (VL) in urban areas. Therefore, studies on this species provide important data for public health. Thus, the objective of the present study was to ascertain the seroprevalence of canine VL (CVL) and the associated factors in the Brejo Paraibano microregion, northeastern Brazil. A total of 409 dogs were sampled from the eight municipalities of the microregion: Alagoa Grande, Alagoa Nova, Areia, Bananeiras, Borborema, Matinhas, Pilões and Serraria. The diagnosis of CVL was made using an enzyme-linked immunosorbent assay (ELISA S7®), through which the prevalence observed was 29.3%. By robust Poisson regression analysis two factors were associated with seroprevalence: illiterate/incomplete elementary owner's education level (prevalence ratio = 1.57; 95% CI = 1.05-2.34; p-value = 0.027) and tick infestation (prevalence ratio = 1.82; 95% CI = 1.27-2.61; p-value = 0.001). It is concluded that the seroprevalence of CVL in the Brejo Paraibano microregion is high. The factors associated with seroprevalence indicated the importance to develop socioeducational actions on the population, and the finding that tick infestation was associated with seroprevalence shows that there is a need for investigation regarding the role of ticks in the epidemiology of CVL.


Assuntos
Doenças do Cão/epidemiologia , Leishmaniose Visceral/epidemiologia , Distribuição Animal , Animais , Brasil/epidemiologia , Reservatórios de Doenças/parasitologia , Reservatórios de Doenças/veterinária , Doenças do Cão/sangue , Doenças do Cão/parasitologia , Cães , Escolaridade , Feminino , Humanos , Leishmaniose Visceral/sangue , Leishmaniose Visceral/veterinária , Masculino , Prevalência , Fatores de Risco , Estudos Soroepidemiológicos , Infestações por Carrapato/veterinária
13.
Rev Bras Parasitol Vet ; 29(2): e021019, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32428187

RESUMO

The midwest region of Brazil has witnessed an increase in the number of cases of human (HVL) and canine visceral leishmaniasis (CVL). The aim of the present study was to evaluate the population's perception of these diseases, factors associated with CVL, its spatial distribution, and the prevalence of anti-Leishmania spp. in 385 dogs, determined using a commercially available immunochromatographic rapid test and confirmed using enzyme-linked immunosorbent assay (ELISA). Of the 385 samples, 54 were positive for CVL and confirmed by ELISA, corresponding to a prevalence of 14%. Knowledge of signs of CVL by tutors (p = 0.038); previous occurrence of CVL in the vicinity (p = 0.022); symptomatic dog(s) (p = 0.014), splenomegaly (p = 0.055), and ear ulcer(s) (p = 0.059) were significantly associated with CVL. The results revealed a significant prevalence of CVL spatially distributed in rural and urban contexts. The association between environmentally related variables and perception and the occurrence of CVL underscores the importance of implementing control and prevention strategies primarily focused on environmental management and health education activities.


Assuntos
Doenças do Cão/parasitologia , Leishmaniose Visceral/epidemiologia , Fatores Etários , Distribuição Animal , Animais , Anticorpos Antiprotozoários/sangue , Brasil/epidemiologia , Cidades/epidemiologia , Estudos Transversais , Doenças do Cão/sangue , Doenças do Cão/epidemiologia , Cães , Características da Família , Feminino , Humanos , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/veterinária , Masculino , Percepção , Prevalência , Análise Espacial , Inquéritos e Questionários
14.
PLoS Negl Trop Dis ; 14(5): e0008254, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32365060

RESUMO

BACKGROUND: Visceral leishmaniasis (VL) or Kala-azar has been a major public health problem in Bihar, India, for several decades. A few VL infected districts including Vaishali have reported >600 cases annually. Hence, in 2015, the Government of India entrusted ICMR-Rajendra Memorial Research Institute of Medical Sciences, Patna, to implement an integrated control strategy for achieving the VL elimination target (<1 case per 10,000 people at the block level) in the Vaishali District of Bihar. METHODOLOGY: This study was conducted between January 2015 and December 2016. An integrated control strategy including the spatio-temporal mapping of VL-case distribution, active case detection, chemical-based vector control using indoor residual spraying (IRS), community awareness campaigns, the training of IRS members, the training of medical doctors for effective treatment, daily monitoring and the supervision of IRS activities, logistic management, post-IRS quality assurance, epidemiological surveillance, and entomological monitoring was performed. An insecticide quantification test was performed for evaluating the IRS quality on sprayed walls. A modern compression pump was used to maintain spray quality on different wall surfaces. The impact of IRS was assessed through sand fly collection in human dwellings and cattle sheds in pre- and post-IRS. The insecticide susceptibility of local P. argentipes was performed before each IRS round (in February and June) during 2015-2016. Statistical analysis such as the mean, percentage, and 95% CI were used to summarize the results. FINDINGS: All 16 blocks of the Vaishali District achieved the VL elimination target in 2016. The integrated VL control strategy helped reduce the number of VL cases from 664 in 2014 to 163 in 2016 and the number of endemic villages from 282 in 2014 to 142 in 2016. The case reduction rate was increased from 22.6% in 2014 to 58.8% in 2016. On average, 74 VL infected villages became Kala-azar free each year from 2015 to 2016. CONCLUSIONS: The results of this study suggest that the elimination of VL is possible from all endemic blocks of Bihar if the integrated Vaishali VL control strategy is applied under strong monitoring and supervision.


Assuntos
Controle de Doenças Transmissíveis/métodos , Controle de Doenças Transmissíveis/organização & administração , Erradicação de Doenças , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/prevenção & controle , Animais , Bovinos , Doenças Endêmicas , Características da Família , Feminino , Abrigo para Animais , Humanos , Índia/epidemiologia , Masculino , Resultado do Tratamento
15.
PLoS One ; 15(4): e0230610, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32240188

RESUMO

BACKGROUND: The development of rK39-based immunochromatographic rapid diagnostic tests represents an important advance for serodiagnosis of visceral leishmaniasis, being cheap and easy to use at the point of care (POC). Although the use of rK39 have considerably improved the sensitivity and specificity of serological tests compared with total antigens, great variability in sensitivity and specificity was reported. This study aimed at the evaluation of "Kalazar Detect™ Rapid Test, Whole Blood" (Kalazar Detect RDT) for Visceral Leishmaniasis (VL) diagnosis using oral fluid, whole blood and serum specimens collected at different endemic areas of VL of Brazil. METHODOLOGY: To evaluate Kalazar Detect RDT, oral fluid, whole blood and serum specimens from 128 VL patients, 85 healthy individuals, 22 patients with possible cross-reactivity diseases and 20 VL/aids coinfected patients were collected and assayed at the POC. PRINCIPAL FINDINGS AND CONCLUSIONS: The performance of Kalazar Detect RDT in whole blood and serum was similar; however, using oral fluid, the sensitivity was low. Particularly in samples from the city of Natal, Rio Grande do Norte state in Northeastern Brazil, we observed low sensitivity, 80.0% (95% CI: 62.7-90.5), using whole blood and serum, and poor sensitivity, 43.3% (95% CI: 27.4-60.8) with oral fluid. Those values were much lower than in the other regions, where sensitivity ranged from 92.7-96.3% in whole blood and serum, and 80.0-88.9% in oral fluid. Besides, in VL/aids coinfected patients, lower sensitivity was achieved compared with VL patients. In samples from Natal, the sensitivity was 0.0% (95% CI: 0.0-49.0) and 25.0% (95% CI: 4.6-69.9), using oral fluid and serum/whole blood, respectively; in samples from the other regions, the sensitivity ranged from 40.0-63.6% and 80.0-81.8%, respectively. As for specificity, high values were observed across the fluids, 100.0% (95% CI: 96.5-100.0) in whole blood, 96.3% (95% CI: 90.8-98.5) in serum, and 95.3% (95% CI: 89.5-98.0) in oral fluid; across localities, specificity ranged from 85.7-100.0%. Serum samples sent by the collaborating centers to Instituto de Medicina Tropical (n = 250) were tested by Kalazar Detect RDT, Direct Agglutination Test, Indirect immunofluorescence assay, Enzyme-linked immunosorbent assay, and IT-Leish® RDT. The regional difference in the performance of rK39-based RDT and lower sensitivity in Leishmania/HIV coinfected patients raise concern on the routine use of these products for the diagnosis of VL.


Assuntos
Líquidos Corporais/química , Cromatografia de Afinidade/métodos , Testes Diagnósticos de Rotina/métodos , Leishmania/isolamento & purificação , Leishmaniose Visceral/diagnóstico , Proteínas de Protozoários/imunologia , Testes Sorológicos/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Antiprotozoários/sangue , Anticorpos Antiprotozoários/imunologia , Antígenos de Protozoários/imunologia , Brasil/epidemiologia , Criança , Pré-Escolar , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Lactente , Leishmaniose Visceral/sangue , Leishmaniose Visceral/epidemiologia , Masculino , Pessoa de Meia-Idade , Sistemas Automatizados de Assistência Junto ao Leito , Adulto Jovem
16.
PLoS Negl Trop Dis ; 14(4): e0008253, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32324738

RESUMO

BACKGROUND: In the Mediterranean basin, Leishmania infantum is the causative agent of visceral leishmaniasis (VL), a zoonosis in which the dog is the primary domestic reservoir, although wildlife may have a leading role in the sylvatic cycle of the disease in some areas. Infections without disease are very frequent. There is limited information regarding the role that VL patients and asymptomatic infected individuals could be playing in the transmission of L. infantum. Xenodiagnosis of leishmaniasis has been used in this descriptive study to explore the role of symptomatic and asymptomatic infected individuals as reservoirs in a recent focus of leishmaniasis in southwestern Madrid, Spain. METHODOLOGY AND MAIN FINDINGS: Asymptomatic blood donors (n = 24), immunocompetent patients who were untreated (n = 12) or treated (n = 11) for visceral leishmaniasis (VL), and immunocompromised patients with VL (n = 3) were enrolled in the study. Their infectivity to Phlebotomus perniciosus was studied by indirect xenodiagnosis on peripheral blood samples. Quantitative polymerase chain reaction of blood samples from immunocompetent patients untreated for VL and immunocompromised untreated, treated and under secondary prophylaxis for VL was performed. Antibodies against Leishmania were studied by indirect fluorescent antibody and rK39-immunochromatographic tests. A lymphoproliferative assay with a soluble Leishmania antigen was used to screen for leishmaniasis infection in the healthy population. Sixty-two xenodiagnostic tests were carried out and 5,080 sand flies were dissected. Positive xenodiagnosis was recorded in four patients, with different sand fly infection rates: 1 immunosuppressed HIV / L. infantum coinfected asymptomatic patient, 1 immunosuppressed patient with multiple myeloma and symptomatic active VL, and 2 immunocompetent patients with untreated active VL. All blood donors were negative for both xenodiagnosis and conventional PCR. CONCLUSIONS / SIGNIFICANCE: There is no consensus amongst authors on the definition of an 'asymptomatic case' nor on the tools for screening; we, therefore, have adopted one for the sake of clarity. Immunocompetent subjects, both infected asymptomatics and those treated for VL, are limited in number and appear to have no epidemiological relevance. The impact is limited for immunocompetent patients with untreated active VL, whilst immunosuppressed individuals undergoing immunosuppressive therapy and immunosuppressed individuals HIV / L. infantum coinfected were the most infectious towards sand flies. It is noteworthy that the HIV / L. infantum coinfected patient with asymptomatic leishmaniasis was easily infectious to sand flies for a long time, despite being under continuous prophylaxis for leishmaniasis. Accordingly, screening for latent Leishmania infection in HIV-infected patients is recommended in scenarios where transmission occurs. In addition, screening for VL in HIV-infected patients who have spent time in VL-endemic areas should also be implemented in non-endemic areas. More research is needed to better understand if some asymptomatic coinfected individuals contribute to transmission as 'super-spreaders'.


Assuntos
Reservatórios de Doenças , Transmissão de Doença Infecciosa , Leishmania infantum/isolamento & purificação , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/transmissão , Adulto , Animais , Anticorpos Antiprotozoários/sangue , Doenças Assintomáticas/epidemiologia , DNA de Protozoário/sangue , Feminino , Humanos , Leucócitos Mononucleares/imunologia , Masculino , Pessoa de Meia-Idade , Psychodidae/parasitologia , Espanha/epidemiologia
17.
Mem Inst Oswaldo Cruz ; 115: e190349, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32348406

RESUMO

BACKGROUND: Visceral leishmaniasis (VL) is relevant for human and animal public health. Several factors have been associated with the risk of Leishmania infantum infection in dogs. However, dog owner characteristics have been rarely explored. OBJECTIVES: To estimate the prevalence and to identify the associated factors for VL infection including dog owners characteristics. METHODS: A cross-sectional study was conducted including dogs from an endemic canine visceral leishmaniasis (CVL) region in the Federal District, Brazil. The infection was detected using parasitological, serological, and molecular methods. The associated factors were identified through Poisson regression modelling. FINDINGS: The prevalence of infection was 26.25% [95% confidence interval (CI): 20.05 to 33.57]. The associated factors were: short coat prevalence ratio (PR) = 2.33 (95% CI: 1.02 to 5.22); presence of backyard with predominance of soil and/or vegetation PR = 4.15 (95% CI: 1.35 to 12.77); and highest gross family income score PR = 2.03 (95% CI: 1.16 to 3.54). MAIN CONCLUSION: This is the first study that relates higher socioeconomic status of dog owners as an independent factor associated with higher prevalence of VL infection, along with other strongly associated factors related to receptive environment for phlebotomines. Our findings strengthen the need for exploration of the biological and behavioural bases linking dog owner characteristics to the risk of canine infection in prospective cohort studies.


Assuntos
Doenças do Cão/epidemiologia , Leishmaniose Visceral/veterinária , Animais , Brasil/epidemiologia , Estudos Transversais , Doenças do Cão/diagnóstico , Cães , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Humanos , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/epidemiologia , Masculino , Prevalência , Estudos Prospectivos , Fatores de Risco , Fatores Socioeconômicos
18.
BMC Public Health ; 20(1): 446, 2020 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-32248804

RESUMO

BACKGROUND: Visceral leishmaniasis (VL) is caused by protozoa of the Leishmania donovani complex. Annually, an estimated 500,000 cases of VL are reported globally posing a public health challenge. The objectives of our study were to confirm and determine the magnitude of VL outbreak, characterize the outbreak clinically and epidemiologically and evaluate the county preparedness and response in Marsabit County, Kenya. METHODS: A retrospective review of laboratory registers and patients' clinical notes was done at Marsabit County Hospital. Cases were persons with confirmed VL diagnosis either by microscopy, serology or molecular technique coming from Marsabit County from May to October 2014. Cases were interviewed using structured questionnaire to collect clinical and epidemiologic information. Blood samples were collected from cases for laboratory confirmation. RESULTS: A total of 136 cases were confirmed of which 77% (105) were male with a median age of 17 (IQR: 22) years and 9.6% (13) case fatality rate. All cases were admitted at Marsabit County Referral Hospital, Kenya. Medical records of 133 cases were retrieved. Of the 133 cases, 102 (77%) presented with fever, 43 (32%) with splenomegaly, 26 (20%) with hepatomegaly and 96 (72%) were managed with Sodium stibogluconate (SSG) monotherapy. Thirty-four cases (26%) received Full haemogram (FHG) test and none had more than one Liver Function Tests (LFTs) in a span of 6 months. Presenting with headache (OR: 4.21, 95% CI: 1.10-16.09) and hepatomegaly (OR: 4.2, 95% CI: 1.30-14.11) were associated with VL death. No VL case management training had been conducted nor VL treatment guidelines distributed among health care workers (HCWs) in the last 1 year. CONCLUSIONS: VL cases were confirmed. Inadequate case monitoring and management was evident. VL case management sensitization training was conducted. The County health department should put in place one health VL surveillance and facilitate periodic case management trainings.


Assuntos
Surtos de Doenças , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/epidemiologia , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Febre/epidemiologia , Humanos , Lactente , Quênia/epidemiologia , Leishmania/isolamento & purificação , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
19.
Mem Inst Oswaldo Cruz ; 115: e190298, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32130366

RESUMO

BACKGROUND: Leishmaniases are considered a major public health problem in South America, specifically in Brazil. Moreover, the transmission and epidemiology of leishmaniasis are possibly associated with climatic and environmental variations. OBJECTIVE: This study aimed to assess the association between the extreme climatic phenomenon El Niño-Southern Oscillation (ENSO), the maximum and minimum variations of temperature, precipitation, and soil moisture and the incidence of visceral leishmaniasis (VL) in Mato Grosso do Sul (MS), Brazil, from 2002 to 2015. METHODS: The Niño 3.4 index was used for the ENSO variation. The other climatic data were obtained from the climatic tool TerraClimate. Records regarding VL were obtained from the Notification of Injury Information System. FINDINGS: From 2002 to 2015, there were 3,137 cases of VL recorded in MS. The annual incidence of the disease was negatively associated with the ENSO index and soil moisture in MS. The VL incidence increased during the negative phase of ENSO and decreased during the positive phase. MAIN CONCLUSIONS: The results demonstrated that the interannual cycles of incidence of human VL are significantly associated with the occurrence of the ENSO phenomenon and its phases, El Niño and La Niña.


Assuntos
El Niño Oscilação Sul , Leishmaniose Visceral/epidemiologia , Brasil/epidemiologia , Humanos , Incidência , Estações do Ano , Análise Espacial , Temperatura
20.
BMC Infect Dis ; 20(1): 214, 2020 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-32164607

RESUMO

BACKGROUND: In Ethiopia, by the end of 2018, an estimated 690,000 people are infected with HIV and the annual cases of Visceral Leishmaniasis (VL) is estimated to be between 4000 and 5000 with over 3.2 million people are at risk. Northwest Ethiopia accounts for over 60% cases of VL in the country. Prevalence of HIV infection among VL infected people in Ethiopia has not yet been synthesized. Therefore, we aimed to estimate the pooled prevalence of HIV infection among VL infected people in Northwest Ethiopia with the hope that it would guide the development of a more robust and cost-effective intervention strategies. METHODS: In this systematic review and meta-analysis, we searched six international databases: PubMed, Ovid MEDLINE®, Embase, Scopus, Google Scholar, and ProQuest Dissertations & Theses. We also searched reference lists of included studies and Ethiopian universities electronic thesis and dissertation repositories. The search was performed until June 30,2019. Funnel plot symmetry visualization confirmed by Egger's regression asymmetry test and Begg rank correlation methods was used to assess publication bias. Pooled prevalence estimate was calculated using Der Simonian and Laird's random Effects model. We went further to perform univariate meta-regression and subgroup analysis to identify a possible sources of heterogeneity among the studies. STATA software (version 14, Texas, USA) was used for analysis. RESULTS: From 1286 citations identified by our search, 19 relevant studies with 5355 VL infected individuals were included in this meta-analysis. The pooled prevalence of HIV infection among VL infected individuals in Northwest Ethiopia was 24% (95%CI: 17-30%). The result of sensitivity analysis demonstrated that the pooled prevalence estimate was robust and not one-study dependent. The pooled prevalence estimate of HIV infection among VL infected people in Northwest Ethiopia ranged from 20.88% (95%CI: 15.91-25.86) to 24.86% (95%CI: 18.57-31.14) after a single study was deleted. CONCLUSIONS: The burden of HIV infection in people infected with VL in Northwest Ethiopia is considerably high. Integrating HIV/AIDS surveillance among VL infected people would improve case detection as well as prevention and control of disease spread.


Assuntos
Infecções por HIV/epidemiologia , Leishmaniose Visceral/epidemiologia , Coinfecção/epidemiologia , Etiópia/epidemiologia , Humanos , Leishmaniose Visceral/virologia , Prevalência
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