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1.
Trans R Soc Trop Med Hyg ; 115(3): 229-235, 2021 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-33580952

RESUMO

BACKGROUND: In March 2020, India declared a nationwide lockdown to control the spread of coronavirus disease 2019. As a result, control efforts against visceral leishmaniasis (VL) were interrupted. METHODS: Using an established age-structured deterministic VL transmission model, we predicted the impact of a 6- to 24-month programme interruption on the timeline towards achieving the VL elimination target as well as on the increase of VL cases. We also explored the potential impact of a mitigation strategy after the interruption. RESULTS: Delays towards the elimination target are estimated to range between 0 and 9 y. Highly endemic settings where control efforts have been ongoing for 5-8 y are most affected by an interruption, for which we identified a mitigation strategy to be most relevant. However, more importantly, all settings can expect an increase in the number of VL cases. This increase is substantial even for settings with a limited expected delay in achieving the elimination target. CONCLUSIONS: Besides implementing mitigation strategies, it is of great importance to try and keep the duration of the interruption as short as possible to prevent new individuals from becoming infected with VL and continue the efforts towards VL elimination as a public health problem in India.


Assuntos
/epidemiologia , Controle de Doenças Transmissíveis/organização & administração , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/prevenção & controle , Humanos , Índia/epidemiologia , Doenças Negligenciadas/epidemiologia , Doenças Negligenciadas/prevenção & controle , Pandemias
2.
Rev Soc Bras Med Trop ; 53: e20200680, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33331613

RESUMO

INTRODUCTION: The use of insecticide-impregnated dog collars is a potentially useful tool for the control of visceral leishmaniasis. The objective of the present study was to perform a cost-effectiveness analysis of a program based on insecticide-impregnated collars compared to traditional visceral leishmaniasis control strategies used in Brazil. METHODS: A cost-effectiveness analysis was performed from the perspective of the Unified Health System, using data from the Visceral Leishmaniasis Control Program implemented in the municipality of Montes Claros, Minas Gerais. The direct costs of the three control strategies, which were 1) canine infection screening + sacrifice, 2) residual chemical control of the vector, and 3) insecticide-impregnated dog collars (Scalibor®), were evaluated over the two-year study period. RESULTS: The total cost of the program in the area subjected to the traditional control strategies (strategies 1 and 2; control area) was R$ 1,551,699.80, and in the area subjected to all three control strategies (intervention area), it was R$ 1,898,190.16. The collar program was considered highly cost-effective at preventing canine visceral leishmaniasis (incremental cost-effectiveness ratio of approximately R$ 578 per avoided dog sacrifice). CONCLUSIONS: These results provide support for the decision by the Brazilian Ministry of Health in 2019 to provide insecticide-impregnated collars for the control of canine visceral leishmaniasis in a pilot project.


Assuntos
Doenças do Cão , Inseticidas , Leishmaniose Visceral , Piretrinas , Animais , Brasil , Análise Custo-Benefício , Doenças do Cão/prevenção & controle , Cães , Leishmaniose Visceral/prevenção & controle , Leishmaniose Visceral/veterinária , Nitrilos , Projetos Piloto
3.
PLoS One ; 15(9): e0238601, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32881961

RESUMO

Canines are proven reservoir hosts of Leishmania infantum, the causative agent of human zoonotic visceral leishmaniasis, and therefore domestic dogs play a central role in transmitting the disease to humans. Studies on the effect of insecticide-impregnated dog collars for controlling canine visceral leishmaniasis (CanL) have been increasing; however, meta-analysis has not been conducted. This study assessed the effectiveness of insecticide-impregnated dog collars for preventing CanL. We searched (PubMed, Web of Science, Scopus, Embase, Ovid Medline(R), and Cochrane library), from inception until 2 May 2020. Two authors independently performed articles screening and data extraction. We applied the RoB 2.0 tool to evaluate the risk of bias in randomized trials, while the ROBINS-I tool was used for non-randomized trials. I-squared statistics(I2) and funnel plot and Egger's test, respectively, were used to assesses heterogeneity between studies and publication bias. Relative Risk (RR) and 95% Confidence Interval (CI) were calculated using the random-effects model in Stata 14 software. Out of 242 citations identified, 14 studies comprising 3786 collared dogs and 3428 uncollared dogs were eligible for meta-analysis. The use of deltamethrin-impregnated dog collars(DMC) showed an overall effectiveness of 54% (95%CI: 35-65%, I2 = 63.2%, P = 0.002) in decreasing incidence of CanL, while 10% imidacloprid and 4.5% flumethrin collars provided an overall effectiveness of 90% (95%CI: 80-96%, I2 = 0.0%, P = 0.376). DMC efficacy stratified by follow-up duration was estimated to be 58% (RR = 0.42, 95%CI: 0.20-0.87), 54% (RR = 0.46, 95%CI: 0.31-0.68), 53% (RR = 0.47, 95%CI: 0.29-0.82) for follow-up periods of 5 to 6 months, 1 year and 2 years, respectively. The current evidence indicates that using insecticide-impregnated dog collars can reduce the risk of CanL caused by L. infantum. Therefore, insecticide-impregnated dog collars could be a viable alternative for inclusion as a public health measure for controlling CanL.


Assuntos
Doenças do Cão/prevenção & controle , Inseticidas/farmacologia , Leishmania infantum/efeitos dos fármacos , Leishmaniose Visceral/prevenção & controle , Administração Cutânea , Animais , Doenças do Cão/parasitologia , Cães , Leishmaniose Visceral/veterinária , Neonicotinoides/farmacologia , Nitrilos/farmacologia , Nitrocompostos/farmacologia , Piretrinas/farmacologia
4.
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
5.
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
6.
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
7.
Parasitol Res ; 119(8): 2609-2622, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32535734

RESUMO

The treatment against visceral leishmaniasis (VL) presents problems, mainly related to the toxicity and/or high cost of the drugs. In this context, a prophylactic vaccination is urgently required. In the present study, a Leishmania protein called LiHyE, which was suggested recently as an antigenic marker for canine and human VL, was evaluated regarding its immunogenicity and protective efficacy in BALB/c mice against Leishmania infantum infection. In addition, the protein was used to stimulate peripheral blood mononuclear cells (PBMCs) from VL patients before and after treatment, as well as from healthy subjects. Vaccination results showed that the recombinant (rLiHyE) protein associated with liposome or saponin induced effective protection in the mice, since significant reductions in the parasite load in spleen, liver, draining lymph nodes, and bone marrow were found. The parasitological protection was associated with Th1-type cell response, since high IFN-γ, IL-12, and GM-CSF levels, in addition to low IL-4 and IL-10 production, were found. Liposome induced a better parasitological and immunological protection than did saponin. Experiments using PBMCs showed rLiHyE-stimulated lymphoproliferation in treated patients' and healthy subjects' cells, as well as high IFN-γ levels in the cell supernatant. In conclusion, rLiHyE could be considered for future studies as a vaccine candidate against VL.


Assuntos
Adjuvantes Imunológicos/administração & dosagem , Antígenos de Protozoários/administração & dosagem , Leishmania infantum/imunologia , Leishmaniose Visceral/prevenção & controle , Animais , Antígenos de Protozoários/imunologia , Feminino , Humanos , Imunogenicidade da Vacina , Leishmaniose Visceral/imunologia , Leishmaniose Visceral/parasitologia , Leucócitos Mononucleares/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Carga Parasitária , Células Th1/imunologia , Vacinação
8.
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
9.
Parasite Immunol ; 42(9): e12732, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32418227

RESUMO

Visceral leishmaniasis (VL) is caused by a protozoan parasite Leishmania donovani mainly influencing the population of tropical and subtropical regions across the globe. The arsenal of drugs available is limited, and prolonged use of such drugs makes parasite to become resistant. Therefore, it is very imperative to develop a safe, cost-effective and inexpensive vaccine against VL. Although in recent years, many strategies have been pursued by researchers, so far only some of the vaccine candidates reached for clinical trial and more than half of them are still in pipeline. There is now a broad consent among Leishmania researchers that the perseverance of parasite is very essential for eliciting a protective immune response and may perhaps be attained by live attenuated parasite vaccination. For making a live attenuated parasite, it is very essential to ensure that the parasite is deficient of virulence and should further study genetically modified parasites to perceive the mechanism of pathogenesis. So it is believed that in the near future, a complete understanding of the Leishmania genome will explore clear strategies to discover a novel vaccine. This review describes the need for a genetically modified live attenuated vaccine against VL, and obstacles associated with its development.


Assuntos
Leishmania donovani/imunologia , Vacinas contra Leishmaniose/imunologia , Leishmaniose Visceral/prevenção & controle , Animais , Humanos , Leishmania donovani/patogenicidade , Leishmaniose Visceral/imunologia , Vacinas Atenuadas/imunologia
10.
Int J Parasitol ; 50(3): 171-176, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32126240

RESUMO

Prevention of canine Leishmania infantum infection is critical to management of visceral leishmaniasis in people living in endemic areas of Brazil. A bill (PL 1738/11), currently under consideration, proposes to establish a national vaccination policy against canine leishmaniasis in Brazil. However, there is no solid scientific evidence supporting the idea that this could reduce transmission from infected vaccinated dogs to sand flies to a level that would significantly reduce the risk of L. infantum infection or visceral leishmaniasis in humans. Thus, we advocate that insecticide-impregnated collars should the first line protective measure for public health purposes and that vaccines are applied on a case-by-case, optional basis for individual dog protection.


Assuntos
Leishmania infantum/imunologia , Leishmaniose Visceral , Psychodidae/parasitologia , Piretrinas/administração & dosagem , Vacinação/veterinária , Administração Tópica , Animais , Brasil/epidemiologia , Doenças do Cão/prevenção & controle , Doenças do Cão/transmissão , Cães , Humanos , Insetos Vetores/efeitos dos fármacos , Insetos Vetores/parasitologia , Inseticidas/administração & dosagem , Inseticidas/farmacologia , Vacinas contra Leishmaniose , Leishmaniose Visceral/prevenção & controle , Leishmaniose Visceral/transmissão , Leishmaniose Visceral/veterinária , Psychodidae/efeitos dos fármacos , Piretrinas/farmacologia
11.
Cad Saude Publica ; 36(2): e00221418, 2020.
Artigo em Português | MEDLINE | ID: mdl-32130320

RESUMO

Visceral leishmaniasis is an emerging and neglected disease that is currently expanding to urban areas. The incidence of human disease is related to canine infection. Araçatuba and Birigui are municipalities (counties) in the state of São Paulo, Brazil, with 8-10% seroprevalence of canine infection and that employ control strategies targeting the canine reservoir, based on serological survey and culling of seropositive dogs. Using data from these control programs to parameterize mathematical models, this study assessed the efficacy of these activities. We estimated that current control is capable of reducing the incidence of canine visceral leishmaniasis (CVL) by approximately 20%. Assuming continuous control and three times the current serological survey activities in Araçatuba and Birigui, culling dogs with a positive CVL diagnosis would be effective for the control of canine infection. Although theoretically possible, in practice the control of CVL with the currently recommended strategies is insufficient, since it would require overcoming the difficulties in these activities, such as lack of material, human, and financial resources, besides associated ethical and legal issues.


Assuntos
Doenças do Cão/prevenção & controle , Leishmaniose Visceral/veterinária , Animais , Brasil , Cidades , Cães , Humanos , Leishmaniose Visceral/prevenção & controle , Modelos Teóricos , Estudos Soroepidemiológicos , Inquéritos e Questionários
12.
Sci Rep ; 10(1): 4689, 2020 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-32170135

RESUMO

Visceral leishmaniasis is an infectious parasitic disease caused by the protozoan parasites Leishmania donovani and Leishmania infantum. The drugs currently used to treat visceral leishmaniasis suffer from toxicity and the emergence of parasite resistance, and so a better solution would be the development of an effective subunit vaccine; however, no approved vaccine currently exists. The comparative testing of a large number of vaccine candidates requires a quantitative and reproducible experimental murine infection model, but the parameters that influence infection pathology have not been systematically determined. To address this, we have established an infection model using a transgenic luciferase-expressing L. donovani parasite and longitudinally quantified the infections using in vivo bioluminescent imaging within individual mice. We examined the effects of varying the infection route, the site of adjuvant formulation administration, and standardised the parasite preparation and dose. We observed that the increase in parasite load within the liver during the first few weeks of infection was directly proportional to the parasite number in the initial inoculum. Finally, we show that immunity can be induced in pre-exposed animals that have resolved an initial infection. This murine infection model provides a platform for systematic subunit vaccine testing against visceral leishmaniasis.


Assuntos
Modelos Animais de Doenças , Leishmania donovani/imunologia , Vacinas contra Leishmaniose/imunologia , Leishmaniose Visceral/imunologia , Leishmaniose Visceral/parasitologia , Camundongos Transgênicos , Animais , Progressão da Doença , Vacinas contra Leishmaniose/administração & dosagem , Leishmaniose Visceral/patologia , Leishmaniose Visceral/prevenção & controle , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Camundongos , Camundongos Knockout
13.
PLoS Negl Trop Dis ; 14(2): e0008011, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32069283

RESUMO

BACKGROUND: Visceral leishmaniasis (VL) is a deadly disease transmitted by the sand fly Phlebotomus argentipes on the Indian subcontinent, with a promising means of vector control being orally treating cattle with fipronil-based drugs. While prior research investigating the dynamic relationship between timing of fipronil-based control schemes and the seasonality of sand flies provides insights into potential of treatment on a large scale, ecological uncertainties remain. We investigated how uncertainties associated with sand fly ecology might affect our ability to assess efficacy of fipronil-based control schemes. To do this, we used a previously-described, individual-based, stochastic sand fly model to quantify how uncertainties associated with 1) the percentage of female sand flies taking blood meals from cattle, and 2) the percentage of female sand flies ovipositing in organic matter containing feces from treated cattle might impact the efficacy of fipronil-based sand fly control schemes. PRINCIPAL FINDINGS: Assuming no prior knowledge of sand fly blood meal and oviposition sites, the probabilities of achieving effective sand fly population reduction with treatments performed 3, 6 and 12 times per year were ≈5-22%, ≈27-36%, and ≈46-54%, respectively. Assuming ≥50% of sand flies feed on cattle, probabilities of achieving efficacious control increased to ≈8-31%, ≈15-42%, and ≈52-65%. Assuming also that ≥50% of sand flies oviposit in cattle feces, the above probabilities increased further to ≈14-53%, ≈31-81%, and ≈89-97%. CONCLUSIONS: Our assessments of the efficacy of fipronil-based cattle treatments in controlling sand fly populations depend on our assumptions regarding key aspects of sand fly ecology. Assessments are most sensitive to assumptions concerning the percentage of sand flies ovipositing in feces of treated cattle, thus emphasizing the importance of identifying sand fly oviposition sites. Our results place the evaluation of fipronil-based cattle treatment within a broader ecological context, which could aid in the planning and execution of a largescale field trial.


Assuntos
Doenças dos Bovinos/prevenção & controle , Controle de Insetos/métodos , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/prevenção & controle , Psychodidae/efeitos dos fármacos , Pirazóis/farmacologia , Administração Oral , Animais , Bovinos , Doenças dos Bovinos/epidemiologia , Simulação por Computador , Ecossistema , Índia , Mordeduras e Picadas de Insetos/prevenção & controle , Inseticidas/farmacologia , Modelos Biológicos , Pirazóis/administração & dosagem , Incerteza
14.
Acta Trop ; 205: 105387, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32035053

RESUMO

Dog vaccination is considered an effective way of reducing Leishmania infantum infection incidence in the canine population, as well as its transmission to humans. However, the use of partially effective vaccines can have the detrimental effect of "masking" vaccinated asymptomatic carriers, capable of harbouring the parasite and transmitting it to naïve individuals. After eight years on the European market, few studies have been released on CaniLeish® vaccine safety and efficacy. The present study, a one-year randomized CaniLeish® vaccine field trial, was performed in a canine leishmaniosis endemic area and included animals selected from a native dog population (n = 168). No severe adverse reactions were observed in vaccinated dogs (n = 85). Cases of active L. infantum infection were detected by serological, molecular and clinical follow-up of dogs. One-year post-vaccination, no differences in number or severity of L. infantum active infections were observed between study groups (n = 4 in each group). Vaccine-induced cellular immunity, assessed through interferon-γ quantification, showed significantly higher levels of this cytokine one-month post-vaccination in the vaccine group (p < 0.001), but no differences were observed after nine months between trial groups (p = 0.078). These results fail to support the reported CaniLeish® efficacy in the prevention of active L. infantum infection in dogs from endemic areas and naturally exposed to the parasite.


Assuntos
Doenças do Cão/prevenção & controle , Leishmania infantum/imunologia , Vacinas contra Leishmaniose/imunologia , Leishmaniose Visceral/veterinária , Vacinação/veterinária , Animais , Doenças do Cão/epidemiologia , Cães , Feminino , Interferon gama/sangue , Vacinas contra Leishmaniose/efeitos adversos , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/prevenção & controle , Masculino
15.
Am J Trop Med Hyg ; 102(4): 758-767, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32043439

RESUMO

Kala azar occurs among seasonal and migrant agricultural workers in northwest Ethiopia and accounts for almost 60% of the disease burden in the country. We conducted a quantitative study on the level of knowledge and practice of this vulnerable group in relation to kala azar transmission and acceptability of its vector control tools. A total of 403 workers were randomly selected from eight farms using a purposive sampling technique. Knowledge and practice scores were calculated based on 12 and 9 core questions, respectively. Binary logistic regression was used to identify factors associated with knowledge and practice. A large gap in knowledge of the disease and the vector was evident with 61.8%, 24.6%, and 13.6% of the workers having poor, moderate, and good levels of knowledge scores, respectively. Similarly, 95% of the seasonal workers reported poor level of use of protective measures against the bite of the sand fly vector. Good level of knowledge about kala azar and its sand fly vector was statistically associated with formal education (adjusted odds ratio [AOR] = 2.11; 95% CI = 1.17, 3.80; P < 0.05) and previous exposure to health education (AOR = 4.72; 95% CI = 1.99, 11.16; P < 0.001). Despite poor current knowledge and practice, a large proportion of the study participants showed interest in using vector control tools if made available, with 78% of the seasonal and migrant workers expressing some willingness to pay for different measures that can protect against sand fly bites. Therefore, we strongly recommend that comprehensive health education and vector control programs should be provided to these workers.


Assuntos
Agricultura , Leishmaniose Visceral/prevenção & controle , Estações do Ano , Migrantes , Adulto , Animais , Etiópia/epidemiologia , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Mordeduras e Picadas de Insetos/prevenção & controle , Repelentes de Insetos/economia , Repelentes de Insetos/farmacologia , Mosquiteiros Tratados com Inseticida , Masculino , Pessoa de Meia-Idade , Roupa de Proteção/economia , Psychodidae , Adulto Jovem
16.
Pesqui. vet. bras ; 40(2): 107-112, Feb. 2020.
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1098443

RESUMO

Human Visceral Leishmaniasis (VL) is expanding, and it is distributed in the five geographic regions of Brazil, with the Northeast being the region that presents the most significant number of registered cases. The main urban reservoir of the etiological agent of VL is the domestic dog, and it is known that canine cases precede human cases. One of the control actions of VL, recommended by the Ministry of Health, is performing the euthanasia of seropositive dogs. In 2013, in the municipality of Iguatama/MG, the first canine serological survey was carried out in the city, with a prevalence of 8.3% of seropositive dogs for Leishmania infantum. Of the seropositive animals for Canine Visceral Leishmaniasis (CVL) in this survey, 84% were euthanized, and 16% died within two years after diagnosis. No other control measures for CVL were taken in the municipality. The objectives of the present study were to determine the current prevalence of seropositive dogs for CVL in the municipality of Iguatama and to observe the impact of euthanasia of seropositive dogs to VL as the only control measure performed in this municipality, which is considered an enzootic area of the disease. For this, a new canine epidemiological survey was carried out in the municipality of Iguatama, following the guidelines of the Manual of Surveillance and Control of Visceral Leishmaniasis. Blood samples were collected from 270 dogs and tested by DPP® immunochromatographic test and by Enzyme-Linked Immunosorbent Assay (ELISA). The animals that presented inconclusive results had new blood samples collected and analyzed. The only animal that showed a positive result in DPP® and undetermined in the ELISA, in the first evaluation, became seropositive four months later, so this study reinforces the recommendation of the Ministry of Health to reassess dogs that present inconclusive results for CVL. From a total of 270 samples, 21 (7.8%) were reagents in both tests. Thus, the prevalence of seropositive dogs for CVL, in 2017, in the urban area of the municipality of Iguatama was 7.8%. The Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) molecular technique confirmed infection by L. infantum in the ten dogs sampled with CVL-positive serology. The comparison between the current prevalence (after euthanasia) with that found in 2013 (8.3%), there was no significant difference (p=0.764). The prevalence of CVL in the urban area of the municipality of Iguatama is still high, making it possible to presume that the euthanasia of seropositive dogs for CVL, and the absence of monitoring or other interventions measures, did not contribute to decrease the transmission of the parasite and was not sufficient for the control of CVL in the municipality of Iguatama, an area considered as non-endemic to CVL until 2013.(AU)


A Leishmaniose visceral humana (LV) está em franca expansão e distribuída nas cinco regiões geográficas do Brasil, o Nordeste sendo a região em que há o maior número de casos registrados. O principal reservatório urbano do agente etiológico da LV é o cão doméstico e sabe-se que casos caninos antecedem o aparecimento de casos humanos. Uma das ações de controle da LV, preconizada pelo Ministério da Saúde, é a eutanásia dos cães soro reagentes. Em 2013, no município de Iguatama/MG, foi realizado o primeiro inquérito sorológico canino na cidade, sendo constatada uma prevalência de 8,3% de cães soro reagentes para Leishmania infantum. Dos animais com sorologia positiva para Leishmaniose visceral canina (LVC), neste inquérito, 84% foram eutanasiados e 16% foram a óbito em, no máximo, dois anos após o diagnóstico. Nenhuma outra medida de controle para LVC foi realizada no município. Os objetivos deste estudo foram determinar a prevalência atual de cães soro reagentes para LVC no município de Iguatama e observar o impacto das eutanásias de cães soro reagentes para LV como única medida de controle realizada neste município, considerado área enzoótica para a doença. Para isso, foi realizado um novo inquérito epidemiológico canino no município de Iguatama, seguindo as normas do Manual de Vigilância e Controle da Leishmaniose Visceral. Foram colhidas amostras sanguíneas de 270 cães que foram examinadas pelo teste imunocromatográfico DPP® e pelo ensaio imunoenzimático (ELISA). Os animais que apresentaram resultados inconclusivos tiveram novas amostras de sangue coletadas e analisadas. O único animal que apresentou resultado positivo no DPP® e indeterminado no ELISA, na primeira avaliação, soro converteu quatro meses depois, o que reforça a recomendação do Ministério da Saúde de reavaliar os cães que apresentam resultado inconclusivo para LVC. Do total das 270 amostras, 21 foram reagentes nos dois testes. Portanto, a prevalência de cães soro reagentes para LVC, em 2017, na área urbana do município de Iguatama foi igual a 7,8%. A infecção pela espécie Leishmania infantum foi confirmada através da técnica molecular de PCR-RFLP em 10 cães amostrados com sorologia positiva para LVC. A comparação entre a prevalência atual (depois das eutanásias) com a encontrada em 2013 (8,3%), não mostrou diferença significativa (p=0,764). Uma vez que a soro prevalência de LVC na área urbana do município de Iguatama ainda é alta, pode-se supor que a eutanásia dos cães soro reagentes para LVC, somada à ausência de monitoramento e de outras medidas de intervenção, não contribuiu para a diminuição da transmissão do parasito, e não foi suficiente para o controle de LVC no município de Iguatama, uma área considerada, até 2013, indene para LVC.(AU)


Assuntos
Animais , Cães , Cães/parasitologia , Leishmaniose Visceral/prevenção & controle , Leishmaniose Visceral/veterinária , Leishmaniose Visceral/epidemiologia , Controle de Doenças Transmissíveis , Eutanásia Animal
17.
Acta Trop ; 204: 105358, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31987778

RESUMO

Vector control is one of the main aspects to reach the target of eliminating visceral leishmaniasis from Indian sub-continent as set by the World Health Organisation. Data on different aspects of vector like ecology, behaviour, population dynamics and their association with environmental factors are very important for formulating an effective vector control strategy. The present work was designed to study the species abundance and impact of environmental factors on population dynamics of vector P. argentipes in a visceral leishmaniasis endemic area of Malda district, West Bengal. Adult sand flies were collected using light traps and mouth aspirators from twelve kala-azar affected villages of Habibpur block of Malda district, on a monthly basis from January to December, 2018. Morphological and molecular methods were used for species identification. Population dynamics were assessed by man hour density and per night per trap collection. Data were analysed using SPSS software to determine the impact of environmental factors on vector population P. argentipes was found to the predominant species and prevalent throughout the year. A significantly higher number of sand flies were collected from cattle sheds than human dwellings and peri-domestic vegetation. A portion of the P. argentipes population was exophilic and exophagic as evidenced by their collection from peri-domestic vegetation. The highest population density was recorded during April to September. Population dynamics were mostly influenced by average temperature along humidity and rain fall. Resting behaviour of sand flies was not restricted to the lower portion of the wall but equally distributed throughout the wall and ceiling. Programme officials should consider management of outdoor populations of the sand flies and timings of indoor residual spray for chemical control purpose.


Assuntos
Insetos Vetores/fisiologia , Leishmaniose Visceral/epidemiologia , Psychodidae/fisiologia , Animais , Bovinos , Ecologia , Abrigo para Animais , Humanos , Índia/epidemiologia , Inseticidas , Leishmaniose Visceral/prevenção & controle , Densidade Demográfica , Dinâmica Populacional , Temperatura
18.
Lancet Glob Health ; 8(2): e237-e243, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31981555

RESUMO

BACKGROUND: Nepal launched a visceral leishmaniasis (also known as kala-azar) elimination initiative in 2005. We primarily aimed to assess whether transmission of Leishmania donovani had decreased since the launch of the initiative. We also assessed the validity of the direct agglutination test (DAT) as a marker of infection, in view of future surveillance systems. METHODS: We did a repeat survey in a population aged 2 years and older for whom baseline serological data were available from 2006. Data were from three districts in the eastern region of Nepal. The primary outcome of interest was prevalent infection with L donovani as measured with DAT (cutoff value ≥1:3200). We compared age group-specific and cluster-specific seroprevalences in 2016 with those in 2006, using χ2 tests, with a specific focus on the comparison of seroprevalences in children born between 1996 and 2005, and those born between 2006 and 2015. To estimate the overall adjusted risk ratio for being seropositive in 2016 compared with 2006, we fitted a Poisson model controlling for age, sex, and cluster. FINDINGS: Between Oct 17, 2016, and Dec 26, 2016, we assessed 6609 individuals. DAT prevalence in children younger than 10 years was 4·1% (95% CI 3·2-5·4) in 2006 versus 0·5% (0·1-1·7) in 2016 (p<0·0001). Seroprevalence was lower in 2016 than in 2006 in all age groups and in all repeated clusters. The overall adjusted risk ratio of being seropositive was 0·44 (95% CI 0·37-0·52) for 2016 compared with 2006, and 0·04 (0·01-0·16) in children younger than 10 years. INTERPRETATION: Our findings show that transmission of L donovani in Nepal has decreased significantly between 2006 and 2016, coinciding with the elimination programme. DAT seems useful for monitoring of L donovani transmission. FUNDING: The Directorate-General for Development Cooperation of Belgium.


Assuntos
Erradicação de Doenças/estatística & dados numéricos , Erradicação de Doenças/tendências , Doenças Endêmicas/prevenção & controle , Leishmania donovani/imunologia , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/prevenção & controle , Leishmaniose Visceral/transmissão , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Doenças Endêmicas/estatística & dados numéricos , Feminino , Previsões , Humanos , Masculino , Pessoa de Meia-Idade , Nepal/epidemiologia , Fatores de Risco , Estudos Soroepidemiológicos , Inquéritos e Questionários , Adulto Jovem
19.
Parasite Immunol ; 42(2): e12687, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31770453

RESUMO

AIMS: This study aimed at evaluating the DNA vaccination efficacy of Leishmania major-derived MAPK10 against Leishmania donovani infection. METHODS AND RESULTS: MAPK10 is one of the 15 mitogen-activated protein kinases (MAPKs) of Leishmania major. Herein, we expressed the gene through a mammalian vector and tested whether priming with this gene would offer protection against L donovani infection. We report that LmjMAPK10 DNA vaccination using a mammalian expression vector significantly reduces the parasite burden. The protection is accompanied by host-protective T-cell functions, TH 1-type cytokines and elevated leishmanial antigen-specific IgG2a isotype response. T-cell response to the L donovani/challenge infection is associated with increase in IL-12 and IFN-γ, but reduced IL-10 and IL-4 production. CONCLUSIONS: LmjMAPK10 is cross-protective against L donovani infection.


Assuntos
Leishmania donovani/imunologia , Vacinas contra Leishmaniose/imunologia , Leishmaniose Visceral/prevenção & controle , Proteína Quinase 10 Ativada por Mitógeno/imunologia , Proteínas de Protozoários/imunologia , Vacinas de DNA/imunologia , Animais , Anticorpos Antiprotozoários/imunologia , Humanos , Imunoglobulina G/imunologia , Interferon gama/biossíntese , Interleucina-10/biossíntese , Subunidade p35 da Interleucina-12/biossíntese , Interleucina-4/biossíntese , Leishmania donovani/genética , Leishmaniose Visceral/imunologia , Macrófagos/imunologia , Macrófagos/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Proteína Quinase 10 Ativada por Mitógeno/genética , Proteínas de Protozoários/administração & dosagem , Proteínas de Protozoários/genética , Células Th1/imunologia
20.
Trends Parasitol ; 36(1): 29-38, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31718888

RESUMO

Effective diagnosis and treatment of visceral leishmaniasis, together with the study of vectors and reservoirs, can lead to a better understanding of the parasite transmission dynamics and the development of more efficient control measures. Recent studies have applied new methodologies and biomarkers, and these have contributed to the early and rapid diagnosis of the disease; assessment of success of pharmacological treatments; efficient monitoring of immunosuppressed individuals; and to population screening for field trials of vaccine efficacy. This opinion article proposes an update to the diagnostic tools for visceral leishmaniasis and their rational and combined use to establish the real prevalence of infection or of exposure to Leishmania in endemic areas.


Assuntos
Biomarcadores/sangue , Quimiocinas/sangue , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/prevenção & controle , Animais , Humanos
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