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1.
Rev Bras Parasitol Vet ; 29(4): e016620, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33295377

RESUMO

The main clinical, anatomopathological, and molecular aspects of the infection by Leishmania infantum are described in two cats with multicentric cutaneous, nodular, and ulcerated lesions. The animals were submitted to a clinical examination, followed by serological, molecular and parasitological exams, with culture and isolation of the parasite, and subsequent isoenzymatic characterization. The animals were euthanized and necropsied. Case 1 was an adult, female, mixed-bred stray cat. Case 2 was an adult, male, mixed-bred and domiciled cat. Both were positive for the presence of anti-L. infantum antibodies. In the cytology of the cutaneous nodules and lymph nodes, amastigote forms of Leishmania spp. could be visualized, free and in the interior of the macrophages. In the histopathology, the lesions were characterized by nodular granulomatous and/or ulcerative dermatitis, associated to amastigote forms of Leishmania spp. By means of the polymerase chain reaction, the sequence of the L. infantum kDNA minicircle was amplified. It is concluded that the infection by L. infantum occurs in cats in the State of Paraíba, Northeast region of Brazil and the need to understand the immunological profile of the visceral leishmaniasis in the feline population is highlighted with aimed at the control measures in public health.


Assuntos
Doenças do Gato , Leishmania infantum , Leishmaniose Visceral , Animais , Anticorpos Antiprotozoários/sangue , Brasil , Doenças do Gato/diagnóstico , Gatos , DNA de Cinetoplasto/genética , Eutanásia Animal , Feminino , Leishmania infantum/genética , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/transmissão , Leishmaniose Visceral/veterinária , Macrófagos/parasitologia , Masculino , Reação em Cadeia da Polimerase/veterinária
2.
Rev Bras Parasitol Vet ; 29(4): e017820, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33295378

RESUMO

Leishmania infantum infection in cats has been reported in several countries, including Brazil. However, the transmission of visceral leishmaniasis (VL) from cats to another host has not been proven yet. Therefore, the aim of this study was to verify the possibility of L. infantum transmission from cats to dogs. In order to verify the possibility of VL transmission from the cat to the dog, xenodiagnosis was carried out in a VL-positive cat, using 55 female Lutzomyia longipalpis. Five days later, 40 insects were dissected to verify Leishmania infection. The remaining 15 females were fed in a healthy dog. The potential infection of the dog was verified through clinical, serological, parasitological examinations, and PCR, at three, six, and twelve months post-infection. All 55 L. longipalpis females became visibly engorged. Leishmania promastigotes were detected in 27.5% of the dissected insects. Leishmania infection in the dog was confirmed upon first evaluation. DNA sequencing of the parasite isolated from the cat confirmed L. infantum infection and showed 99% similarity with the L. infantum DNA sequences from the dogs. Through this study, it was possible to confirm the L. infantum experimental transmission from a domestic cat to a domestic dog through its biological vector L. longipalpis.


Assuntos
Doenças do Gato , Doenças do Cão , Leishmania infantum , Leishmaniose Visceral , Animais , Brasil , Doenças do Gato/parasitologia , Doenças do Gato/transmissão , Gatos , DNA de Protozoário/química , Doenças do Cão/parasitologia , Doenças do Cão/transmissão , Cães , Feminino , Insetos Vetores/parasitologia , Leishmania infantum/genética , Leishmaniose Visceral/transmissão , Leishmaniose Visceral/veterinária , Psychodidae/parasitologia
3.
Turkiye Parazitol Derg ; 44(3): 158-163, 2020 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-32928724

RESUMO

Objective: In Turkey, leishmaniasis occurs in two clinical forms: cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL). CL has been reported mainly from south-eastern Anatolia and the eastern part of the Mediterranean region, whereas VL is sporadic in almost all geographical regions of Turkey. Both clinical forms of the disease have been recorded in Kayseri province for decades, but no study has been conducted on the sand fly fauna in this area. Therefore, we determine the species composition and population dynamics of sand flies prevalent in Kayseri province and identify possible vector species. Methods: Data related to the recent locations of CL and VL cases were obtained from the Ministry of Health, and sand flies were collected in 14 localities of different districts using CDC light traps. The specimens were transferred to the laboratory in 70% ethanol, and morphological identification to the species level was performed using previously written keys. Results: A total of 1,636 sand fly specimens were collected. Morphological identification revealed eight species of the genus Phlebotomus (P. perfiliewi s.l., P. halepensis, P. simici, P. major s.l., P. papatasi, P. tobbi, P. sergenti and P. mascittii) and one species of the genus Sergentomyia (S. dentata). Among all specimens, members of subgenus Adlerius (54.58%) formed the dominant group, followed by the subgenus Larroussius (43.76%). Conclusion: Our results showed that P. halepensis, belonging to subgenus Adlerius, and P. perfiliewi, belonging to the subgenus, are probable vectors of cutaneous and VL in the province, respectively.


Assuntos
Insetos Vetores/classificação , Leishmaniose Cutânea/transmissão , Leishmaniose Visceral/transmissão , Psychodidae/classificação , Animais , Demografia , Entomologia , Feminino , Humanos , Masculino , Turquia/epidemiologia
4.
Proc Natl Acad Sci U S A ; 117(41): 25742-25750, 2020 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-32973088

RESUMO

Understanding of spatiotemporal transmission of infectious diseases has improved significantly in recent years. Advances in Bayesian inference methods for individual-level geo-located epidemiological data have enabled reconstruction of transmission trees and quantification of disease spread in space and time, while accounting for uncertainty in missing data. However, these methods have rarely been applied to endemic diseases or ones in which asymptomatic infection plays a role, for which additional estimation methods are required. Here, we develop such methods to analyze longitudinal incidence data on visceral leishmaniasis (VL) and its sequela, post-kala-azar dermal leishmaniasis (PKDL), in a highly endemic community in Bangladesh. Incorporating recent data on VL and PKDL infectiousness, we show that while VL cases drive transmission when incidence is high, the contribution of PKDL increases significantly as VL incidence declines (reaching 55% in this setting). Transmission is highly focal: 85% of mean distances from inferred infectors to their secondary VL cases were <300 m, and estimated average times from infector onset to secondary case infection were <4 mo for 88% of VL infectors, but up to 2.9 y for PKDL infectors. Estimated numbers of secondary cases per VL and PKDL case varied from 0 to 6 and were strongly correlated with the infector's duration of symptoms. Counterfactual simulations suggest that prevention of PKDL could have reduced overall VL incidence by up to 25%. These results highlight the need for prompt detection and treatment of PKDL to achieve VL elimination in the Indian subcontinent and provide quantitative estimates to guide spatiotemporally targeted interventions against VL.


Assuntos
Leishmaniose Cutânea/epidemiologia , Leishmaniose Visceral/epidemiologia , Infecções Assintomáticas/epidemiologia , Bangladesh/epidemiologia , Coinfecção/epidemiologia , Coinfecção/transmissão , Busca de Comunicante , Doenças Endêmicas/estatística & dados numéricos , Humanos , Incidência , Leishmaniose Cutânea/prevenção & controle , Leishmaniose Cutânea/transmissão , Leishmaniose Visceral/prevenção & controle , Leishmaniose Visceral/transmissão , Estudos Longitudinais
5.
PLoS One ; 15(9): e0238198, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32946444

RESUMO

Visceral leishmaniasis (VL) is an infectious disease caused by the protozoa Leishmania chagasi, whose main vector in South America is Lutzomyia longipalpis. The disease was diagnosed in the Brazilian state of Espírito Santo (ES) for the first time in 1968. Currently, this disease has been considered endemic in 10 municipalities. Furthermore, the presence of L. longipalpis has been detected in eight other municipalities where the transmission has not been reported thus far. In this study, we performed species distribution modeling (SDM) to identify new and most likely receptive areas for VL transmission in ES. The sandflies were both actively and passively collected in various rural area of ES between 1986 and 2017. The collection points were georeferenced using a global positioning system device. Climatic data were retrieved from the WorldClim database, whereas geographic data were obtained from the National Institute for Space Research and the Integrated System of Geospatial Bases of the State of Espírito Santo. The maximum entropy algorithm was used through the MIAmaxent R package to train and test the distribution models for L. longipalpis. The major contributor to model generation was rocky outcrops, followed by temperature seasonality. The SDM predicted the expansion of the L. longipalpis-prone area in the Doce River Valley and limited the probability of expanding outside its watershed. Once the areas predicted suitable for L. longipalpis occurrence are determined, we can avoid the inefficient use of public resources in conducting canine serological surveys where the vector insect does not occur.


Assuntos
Clima , Geografia , Insetos Vetores/fisiologia , Leishmaniose Visceral/transmissão , Psychodidae/fisiologia , Animais , Brasil , Modelos Estatísticos , Análise Espacial
6.
PLoS Negl Trop Dis ; 14(8): e0008363, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32790716

RESUMO

Visceral leishmaniasis (VL) remains an important public health issue worldwide causing substantial morbidity and mortality. The Indian subcontinent accounted for up to 90% of the global VL burden in the past but made significant progress during recent years and is now moving towards elimination. However, to achieve and sustain elimination of VL, knowledge gaps on infection reservoirs and transmission need to be addressed urgently. Xenodiagnosis is the most direct way for testing the infectiousness of hosts to the vectors and can be used to investigate the dynamics and epidemiology of Leishmania donovani transmission. There are, however, several logistic and ethical issues with xenodiagnosis that need to be addressed before its application on human subjects. In the current Review, we discuss the critical knowledge gaps in VL transmission and the role of xenodiagnosis in disease transmission dynamics along with its technical challenges. Establishment of state of the art xenodiagnosis facilities is essential for the generation of much needed evidence in the VL elimination initiative.


Assuntos
Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/transmissão , Phlebotomus/parasitologia , Xenodiagnóstico , Animais , Ásia , Doenças Assintomáticas , Reservatórios de Doenças/parasitologia , Humanos , Leishmania donovani/fisiologia
7.
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
9.
Medicina (B Aires) ; 80(2): 103-110, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32282314

RESUMO

To diagnose dogs infected by Leishmania infantum rK39 rapid diagnosis test is widely used in the Americas, while dual path platform (DPP) was recently adopted by Brazil. In this study we assessed the performance of rK39-RDT and DPP tests in recent urban transmission scenarios of Argentina. The sensitivity and specificity were evaluated with a sera panel and field samples, taken as true infected those from parasitological and/or PCR positive tests. Since none of these tests can be taken as a gold standard, the performance was also evaluated using Latent Class Analysis, a statistical modeling technique which allows to estimating sensitivity and specificity defining a latent class variable as the reference standard. The sensitivity of both tests in the panel was around 92% (symptomatic dogs 96%, asymptomatic 83%), while the sensitivity in field samples of rK39-RDT was 77%, and DPP 98% (mean in symptomatic dogs 89%, asymptomatic 82%). The specificity was similar for both tests and samples, around 98%. Therefore, these tests are acceptable for program dog population-based studies, as spatial stratification, focus intervention and follow up, and they could be used for individual screening and confirmation of clinical presumptive diagnosis in polysymptomatic dogs. The inability to discriminate between immunity and actual infectiousness suggest that a combination with other non-immunological based tests will be required for highly sensitive/specific diagnosis in order to targeting control measures in individual reservoirs from public health perspective, as for individual management from animal health perspective.


Assuntos
Doenças do Cão/diagnóstico , Leishmaniose Visceral/veterinária , Animais , Argentina , Brasil , Doenças do Cão/transmissão , Cães , Ensaio de Imunoadsorção Enzimática/veterinária , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/transmissão , Reação em Cadeia da Polimerase/veterinária , Sensibilidade e Especificidade
10.
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
11.
PLoS Negl Trop Dis ; 14(3): e0008132, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32150578

RESUMO

Visceral leishmaniasis (VL) in Nepal is found in 61 out of 75 districts including areas previously listed as non- endemic. This study focused on the role of housing conditions and its immediate environment in VL transmission, to limit future transmissions, ensure sustainable vector control and support the VL elimination program. The objective was to explore the risk factors in rural housing-and land lot typologies contributing to clinical VL occurrence and transmission. Housing structures and land lots were examined based on characteristics as risk factors of VL transmission in a case-control analysis. VL cases from 2013-2017 were identified based on the existing database from the Epidemiology and Disease Control Division and District Public Health Office from the plain Terai area (Morang, and Saptari districts) and hilly area (Palpa district) of Nepal. Two hundred and three built environments were analyzed (66 cases and 137 controls). Inferential statistics and logistic regression analysis were performed to determine the association of risk factors with VL. The risk factors with the highest odds of VL were: bamboo walls (adjusted odds ratio (AOR)- 8.1, 95% CI 2.40-27.63, p = 0.001), walls made of leaves/branches (AOR- 3.0, 95% CI 0.84-10.93, p = 0.090), cracks in bedroom walls (AOR- 2.9, 95% CI 0.93-9.19, p = 0.065), and placing sacks near sleeping areas (AOR- 19.2, 95% CI 4.06-90.46, p <0.001). Significant outdoor factors were: lots with Kadam trees (AOR- 12.7, 95% CI 3.28-49.09, p <0.001), open ground-outdoor toilets (AOR- 9.3, 95% CI 2.14-369.85, p = 0.003), moisture in outdoor toilet sheds (AOR- 18.09, 95% CI 7.25-451.01, p = 0.002), nearby- open land (AOR- 36.8, 95% CI 3.14-430.98, p = 0.004), moisture inside animal sheds (AOR- 6.9, 95% CI 1.82-26.66, p = 0.005), and surrounding animals/animals wastes particularly goats (AOR- 3.5, 95% CI 1.09-10.94, p = 0.036). Certain housing and surrounding environmental conditions and characteristics are risk factors for VL. Hence, elimination and educational programs should include the focus on housing improvement and avoidance of risk factors. Longitudinal interventional studies are required to document temporal relationships and whether interventions on these factors will have an impact on Leishmania transmission or burden.


Assuntos
Transmissão de Doença Infecciosa , Meio Ambiente , Habitação , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/transmissão , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Nepal/epidemiologia , Fatores de Risco
12.
Vet Parasitol ; 280: 109058, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32200198

RESUMO

The clinical manifestations most frequently observed in cats with leishmaniasis caused by Leishmania infantum are cutaneous alterations, which suggest a high parasitic load in the skin and the possibility of infecting a vector. This study evaluated the infectiousness of to phlebotomine sand flies cats infected with L. infantum. A total of 12 cats with infection by L. infantum from the city of Teresina, Piauí, Brazil, were included in the study. Cats were diagnosed by direct visualization of the parasite. Laboratory-bred insects, free from infection by Leishmania spp. were offered a blood meal for 60 min on cats infected with L. infantum. On the fifth and sixth day after the blood meal, flies were dissected to assess promastigote forms of the parasite in the digestive system. Eight cats (67 %) were able to infect the vectors. The frequency of infected insects per cat ranged 0.0-94.4%. The mean frequency of insects feeding on cats was 95.2 %. Large numbers of the parasite were observed per insect, but were not quantified. The result confirm that cats are able to infect L. longipalpis, indicating that cats are part of the epidemiological chain of VL, acting as reservoir of the disease.


Assuntos
Doenças do Gato/transmissão , Insetos Vetores/parasitologia , Leishmania infantum/fisiologia , Leishmaniose Visceral/veterinária , Psychodidae/parasitologia , Animais , Brasil , Gatos , Feminino , Leishmaniose Visceral/transmissão , Masculino
13.
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
14.
Parasit Vectors ; 13(1): 96, 2020 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-32087758

RESUMO

BACKGROUND: Since the introduction of miltefosine (MIL) as first-line therapy in the kala-azar elimination programme in the Indian subcontinent, treatment failure rates have been increasing. Since parasite infectivity and virulence may become altered upon treatment relapse, this laboratory study assessed the phenotypic effects of repeated in vitro and in vivo MIL exposure. METHODS: Syngeneic Leishmania donovani lines either or not exposed to MIL were compared for drug susceptibility, rate of promastigote multiplication and metacyclogenesis, macrophage infectivity and behaviour in the sand fly vector, Lutzomyia longipalpis. RESULTS: Promastigotes of both in vitro and in vivo MIL-selected strains displayed a slightly reduced drug susceptibility that was associated with a reduced MIL-accumulation linked to a lower copy number (disomic state) of chromosome 13 harboring the miltefosine transporter (LdMT) gene. In vitro selected promastigotes showed a lower rate of metacyclogenesis whereas the in vivo derived promastigotes displayed a moderately increased growth rate. Repeated MIL exposure did neither influence the parasite load nor metacyclogenesis in the sand fly vector. CONCLUSIONS: Recurrent in vitro and in vivo MIL exposure evokes a number of very subtle phenotypic and genotypic changes which could make promastigotes less susceptible to MIL without attaining full resistance. These changes did not significantly impact on infection in the sand fly vector.


Assuntos
Antiprotozoários/farmacologia , Insetos Vetores/parasitologia , Leishmania donovani/efeitos dos fármacos , Leishmania donovani/fisiologia , Fosforilcolina/análogos & derivados , Psychodidae/parasitologia , Aclimatação , Animais , Resistência a Medicamentos , Humanos , Leishmania donovani/patogenicidade , Leishmaniose Visceral/parasitologia , Leishmaniose Visceral/transmissão , Testes de Sensibilidade Parasitária , Fenótipo , Fosforilcolina/farmacologia , Virulência
15.
BMC Infect Dis ; 20(1): 10, 2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31906924

RESUMO

BACKGROUND: A visceral leishmaniasis outbreak was reported from a village in a low-endemic district of Bihar, India. METHODS: Outbreak investigation with house-to-house search and rapid test of kala-azar suspects and contacts was carried out. Sandfly collection and cone bio-assay was done as part of entomological study. RESULTS: A spatially and temporally clustered kala-azar outbreak was found at Kosra village in Sheikhpura district with 70 cases reported till December 2018. Delay of more than a year was found between diagnosis and treatment of the index case. The southern hamlet with socio-economically disadvantaged migrant population was several times more affected than rest of the village (attack rate of 19.0% vs 0.5% respectively, ORMH = 39.2, 95% CI 18.2-84.4). The median durations between onset of fever to first contact with any health services, onset to kala-azar diagnosis, diagnosis to treatment were 10 days (IQR 4-18), 30 days (IQR 17-73) and 1 day (IQR 0.5 to 3), respectively, for 50 kala-azar cases assessed till June 2017. Three-fourths of these kala-azar cases had out-of-pocket medical expenditure for their condition. Known risk factors for kala-azar such as illiteracy, poverty, belonging to socially disadvantaged community, migration, residing in kutcha houses, sleeping in rooms with unplastered walls and non-use of mosquito nets were present in majority of these cases. Only half the dwellings of the kala-azar cases were fully sprayed. Fully gravid female P. argentipes collected post indoor residual spraying (IRS) and low sandfly mortality on cone-bioassay indicated poor effectiveness of vector control. CONCLUSIONS: There is need to focus on low-endemic areas of kala-azar. The elimination programme should implement a routine framework for kala-azar outbreak response. Complete case-finding, use of quality-compliant insecticide and coverage of all sprayable surfaces in IRS could help interrupt transmission during outbreaks.


Assuntos
Surtos de Doenças , Leishmaniose Visceral/epidemiologia , Migrantes , Animais , Surtos de Doenças/prevenção & controle , Feminino , Humanos , Incidência , Índia/epidemiologia , Controle de Insetos/estatística & dados numéricos , Inseticidas/administração & dosagem , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/terapia , Leishmaniose Visceral/transmissão , Psychodidae/fisiologia , Fatores de Risco
16.
Parasitol Res ; 119(2): 365-384, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31897789

RESUMO

We performed a systematic review of the literature published since 1900 about leishmaniasis a neglected vector-borne disease, focused on environmental and social risk factors for visceral (VL) and cutaneous leishmaniasis (CL) to better understand their impact on the incidence of disease. The search terms were "leishmaniasis" AND "risk factors" using Google Scholar, PudMed, and Scielo. We reviewed 177 articles, 95 studies for VL, 75 for CL, and 7 on both forms. We identified 14 categories of risk factors which were divided into three groups: socioeconomic (7), environmental (5), and climate (2) variables. Socioeconomic factors were also associated with disease incidence in vulnerable human populations of arid and tropical developing regions. Environmental and climate factors showed significant associations with the incidence of VL and CL in all the studies that considered them. Proximity to natural vegetation remnants increased disease risk in both the New and Old World while the climate conditions favorable for disease transmission differed among regions. We propose a common conceptual framework for both clinical forms that highlights networks of interaction among risk factors. In both clinical forms, the interplay of these factors played a major role in disease incidence. Although there are similarities in environmental and socioeconomic conditions that mediate the transmission cycle of tropical, arid, and Mediterranean regions, the behavior of vector and reservoirs in each region is different. Special attention should be given to the possibility of vector adaptation to urban environments in developing countries where populations with low socioeconomic status are particularly vulnerable to the disease.


Assuntos
Clima , Meio Ambiente , Leishmaniose Cutânea/epidemiologia , Leishmaniose Visceral/epidemiologia , Fatores Socioeconômicos , Animais , Vetores de Doenças , Humanos , Incidência , Leishmaniose Cutânea/transmissão , Leishmaniose Visceral/transmissão , Fatores de Risco
17.
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.
Genes (Basel) ; 11(1)2019 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-31861501

RESUMO

Pathogen fitness landscapes change when transmission cycles establish in non-native environments or spill over into new vectors and hosts. The introduction of Leishmania infantum in the Americas into the Neotropics during European colonization represents a unique case study to investigate the mechanisms of ecological adaptation of this important parasite. Defining the evolutionary trajectories that drive L. infantum fitness in this new environment are of great public health importance as they will allow unique insight into pathways of host/pathogen co-evolution and their consequences for region-specific changes in disease manifestation. This review summarizes current knowledge on L. infantum genetic and phenotypic diversity in the Americas and its possible role in the unique epidemiology of visceral leishmaniasis (VL) in the New World. We highlight the importance of appreciating adaptive molecular mechanisms in L. infantum to understand the parasites' successful establishment on the continent.


Assuntos
Leishmania infantum/classificação , Leishmaniose Visceral/transmissão , Oceano Atlântico , Evolução Molecular , Aptidão Genética , Humanos , Leishmania infantum/genética , Fenótipo
20.
Rev. bras. parasitol. vet ; 28(4): 569-573, Oct.-Dec. 2019. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1058005

RESUMO

Abstract Phlebotomines of the genus Lutzomyia are important vector for species of Leishmania, the etiological agent of leishmaniasis. The aim of this study was to assess the diversity of sandflies in an endemic area for Visceral Leishmaniasis (VL). Sampling was performed in four localities on the coast of the municipality of Goiana, state of Pernambuco, Northeastern Brazil. Specimens were collected monthly on three consecutive nights, from November 2017 to October 2018. CDC light traps were installed at a height of 1.5 m above the ground, in two ecotypes (i.e. tree and animal facility), both in peridomestic areas. A total of 5,205 sandflies were collected, among which the species Lutzomyia longipalpis (99.85%; 5,197/5,205) was the most common, followed by Lutzomyia evandroi (0.13%; 07/5,205) and Lutzomyia whitmani (0.02%; 01/5,205). Specimens of L. longipalpis were collected throughout the study period and most of them were found near to the animal facilities. The findings from this research indicate that vectors for Leishmania infantum are present in the study area throughout the year, along with occurrences of vectors relating to Cutaneous Leishmaniasis (CL). Preventive vector control measures need to be implemented in Goiana to reduce the risk of infection for the human and animal populations.


Resumo Flebotomíneos do gênero Lutzomyia são importantes vetores de espécies de Leishmania, agente etiológico das leishmanioses. O objetivo deste estudo foi avaliar a diversidade de flebotomíneos em área endêmica para Leishmaniose Visceral (LV). As coletas foram realizadas em quatro localidades do litoral do município de Goiana, Pernambuco, Nordeste do Brasil. Os espécimes foram coletados mensalmente em três noites consecutivas de novembro de 2017 a outubro de 2018. Foram instaladas armadilhas luminosas modelo CDC a uma altura de 1,5 m acima do solo em dois ecótopos (ex. árvore e instalações de animais), ambos em áreas peridomiciliares. Um total de 5.205 flebotomíneos foi coletado, sendo Lutzomyia longipalpis (99,85%; 5.197/5.205) a mais comum, seguida por Lutzomyia evandroi (0,13%; 07/5.205) e Lutzomyia whitmani (0,02%; 01/5.205). L. longipalpis foi coletada durante todo o período do estudo. A maioria dos espécimes foi detectada perto das instalações dos animais. Os achados deste estudo indicam a presença de vetores de Leishmania infantum na área avaliada ao longo do ano, bem como a ocorrência de vetores relacionados à Leishmaniose Cutânea (LC). Medidas preventivas de controle vetorial devem ser implementadas em Goiana para reduzir o risco de infecção à população humana e animal.


Assuntos
Animais , Masculino , Feminino , Psychodidae/classificação , Insetos Vetores/classificação , Estações do Ano , Brasil , Densidade Demográfica , Doenças Endêmicas , Leishmaniose Visceral/transmissão
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