Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 47
Filtrar
1.
J Infect Dis ; 229(6): 1909-1912, 2024 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-38713583

RESUMEN

In an area endemic with Indian visceral leishmaniasis (VL), we performed direct xenodiagnosis to evaluate the transmission of Leishmania donovani from patients with VL-human immunodeficiency virus (HIV) coinfection to the vector sandflies, Phlebotomus argentipes. Fourteen patients with confirmed VL-HIV coinfection, with a median parasitemia of 42 205 parasite genome/mL of blood, were exposed to 732 laboratory-reared pathogen-free female P argentipes sandflies on their lower arms and legs. Microscopy revealed that 16.66% (122/732) of blood-fed flies were xenodiagnosis positive. Notably, 93% (13/14) of the VL-HIV group infected the flies, as confirmed by quantitative polymerase chain reaction and/or microscopy, and were 3 times more infectious than those who had VL without HIV.


Asunto(s)
Coinfección , Infecciones por VIH , Leishmania donovani , Leishmaniasis Visceral , Leishmaniasis Visceral/epidemiología , Leishmaniasis Visceral/complicaciones , Animales , Humanos , India/epidemiología , Infecciones por VIH/complicaciones , Infecciones por VIH/epidemiología , Femenino , Adulto , Coinfección/virología , Coinfección/epidemiología , Coinfección/parasitología , Leishmania donovani/aislamiento & purificación , Masculino , Phlebotomus/parasitología , Phlebotomus/virología , Enfermedades Endémicas , Persona de Mediana Edad , Adulto Joven , Xenodiagnóstico , Insectos Vectores/parasitología , Insectos Vectores/virología , Adolescente
2.
Pathogens ; 12(4)2023 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-37111500

RESUMEN

Leishmaniases are neglected diseases caused by protozoans of the genus Leishmania that threaten millions of people worldwide. Cutaneous leishmaniasis (CL) caused by L. major is a typical zoonosis transmitted by phlebotomine sand flies and maintained in rodent reservoirs. The female sand fly was assumed to become infected by feeding on the skin lesion of the host, and the relative contribution of asymptomatic individuals to disease transmission was unknown. In this study, we infected 32 Meriones shawi, North African reservoirs, with a natural dose of L. major obtained from the gut of infected sand flies. Skin manifestations appeared in 90% of the animals, and xenodiagnosis with the proven vector Phlebotomus papatasi showed transmissibility in 67% of the rodents, and 45% were repeatedly infectious to sand flies. Notably, the analysis of 113 xenodiagnostic trials with 2189 sand flies showed no significant difference in the transmissibility of animals in the asymptomatic and symptomatic periods; asymptomatic animals were infectious several weeks before the appearance of skin lesions and several months after their healing. These results clearly confirm that skin lesions are not a prerequisite for vector infection in CL and that asymptomatic animals are an essential source of L. major infection. These data are important for modeling the epidemiology of CL caused by L. major.

3.
Viruses ; 15(4)2023 04 20.
Artículo en Inglés | MEDLINE | ID: mdl-37112992

RESUMEN

The role of dogs as reservoir hosts for Toscana virus (TOSV) remains undetermined. This study investigated TOSV and Leishmania infantum infections in one healthy and three infected dogs with Leishmania (A, B, C) following natural exposition to sandfly bites in a focus of zoonotic visceral leishmaniasis (ZVL) located in Northern Tunisia from June to October 2020. At the end of the exposition period, infected and healthy dogs were examined for TOSV and L. infantum infections by xenodiagnosis using a colony of Phlebotomus perniciosus. Pools of freshly engorged P. perniciosus at days 0 and those at days 7 post-feeding were screened for TOSV and L. infantum by nested PCR in the polymerase gene and kinetoplast minicircle DNA, respectively. In the exposure site, P. pernicious is the most abundant sandfly species. The infection rates of sandflies with TOSV and L. infantum were 0.10 and 0.05%, respectively. Leishmania infantum DNA and TOSV RNA were detected in P. perniciosus females fed on dog B and C, respectively. The isolation of TOSV in Vero cells was achieved from two pools containing P. perniciosus fed on dog C. No pathogens were detected in P. perniciosus females fed on dog A and on control dog. We report for the first time the reservoir competence of dog with ZVL in the transmission of TOSV to sandfly vectors in natural settings, in addition to its role as a main reservoir host of L. infantum.


Asunto(s)
Enfermedades de los Perros , Leishmania infantum , Leishmaniasis Visceral , Leishmaniasis , Phlebotomus , Psychodidae , Virus de Nápoles de la Fiebre de la Mosca de los Arenales , Femenino , Chlorocebus aethiops , Perros , Animales , Leishmaniasis Visceral/epidemiología , Leishmaniasis Visceral/veterinaria , Virus de Nápoles de la Fiebre de la Mosca de los Arenales/genética , Leishmania infantum/genética , Túnez/epidemiología , Células Vero , Phlebotomus/genética , ADN , Enfermedades de los Perros/epidemiología
4.
Rev. Soc. Bras. Med. Trop ; 56: e0503, 2023.
Artículo en Inglés | LILACS-Express | LILACS | ID: biblio-1529504

RESUMEN

ABSTRACT Molecular methods have been responsible for a notable increase in the detection of Leishmaniinae infections in wild animals. Determining their infectiousness is of paramount importance in evaluating their epidemiological significance. One of the most efficient ways of determining infectiousness for vector borne diseases is xenodiagnosis with the appropriate vector. However, this is logistically very difficult to accomplish in the field, and an ideal solution is to find a molecular surrogate for xenodiagnosis. In this review we discuss different approaches to the problem by focusing on the infectiousness of Leishmania (Viannia) braziliensis in rodents under laboratory and field conditions. Comparisons with similar studies for other Leishmania species emphasizes that there are pivotal differences in the infectiousness and the importance of asymptomatic infections in different hosts. Potentially the most promising surrogate is the real time quantitative PCR (qPCR). However, its success depends on choosing a tissue that relates to the vector's feeding location and the parasite's tissue tropism. This requires detailed knowledge of the infection of each species in its wild hosts. We conclude that for L. (V.) braziliensis infections in wild rodents the tissue of choice for a molecular xenodiagnostic test, based on the qPCR is blood, providing that a significant number of samples must be examined.

5.
Pathogens ; 11(7)2022 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-35890030

RESUMEN

Chagas disease (ChD) is a vector zoonosis native to the American continent caused by the protozoan parasite Trypanosoma cruzi; the biological vectors are multiple species of hematophagous insects of the family Triatominae. A relevant aspect in the host-parasite relationship is the identification of the various genotypes of T. cruzi called discrete typing units (DTU) that circulate in mammals and vectors. In Chile, it has been described that the DTUs TcI, TcII, TcV, and TcVI circulate in infected humans, vectors, and wild animals. Identifying DTUs has acquired clinical importance, since it has been suggested that different genotypes could cause distinct pathologies, circulate in different geographical areas, and present different sensitivities to trypanocidal drugs. In this study, circulating T. cruzi DTUs in peripheral blood and Triatoma infestans dejections used in xenodiagnosis (XD) were amplified by qPCR in 14 Chilean patients with chronic ChD from highly endemic areas. More positive samples were detected by XD compared to peripheral blood samples, and 64.28% of the cases were simple infections and 35.72% mixed, with a statistically significant difference in the frequency of TcV DTU. This study would suggest that T. infestans from Chile is more competent to amplify one DTU over others, probably due to a process of co-evolution.

6.
Med Vet Entomol ; 36(1): 81-87, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-34724230

RESUMEN

Dogs are reservoir hosts of leishmaniasis caused by Leishmania infantum and transmitted by phlebotomine vectors. The effect of dinotefuran, pyriproxyfen and permethrin spot-on solution (Vectra®3D, Ceva Santé Animale, Libourne, France) on Leishmania transmissibility by naturally infected dogs via reared Phlebotomus perniciosus, was assessed. Dogs affected by leishmaniasis were submitted to xenodiagnosis and 6 infecting >10% of insects were treated topically on day 0. Antifeeding, insecticidal and anti-transmissibility effects were evaluated through xenodiagnoses performed on days 1, 7 and 28, using individual pre-treatment parameters as control. Feeding and mortality rates were assessed at 24 h, whereas promastigote infection, maturation and burden were assessed up to 96 h post blood meal (potentially infectious rate). On day 1, the anti-feeding efficacy was >95% in 4 dogs, insecticidal efficacy 100% in 4 dogs, and anti-transmissibility effect 100% in 6 dogs. Efficacy rates recorded on day 7 were very similar to day 1. On day 28, anti-feeding and insecticidal efficacy values were much broader, ranging 32.6-100% and 7.7-94.4%, respectively. Potentially infectious insects were recorded from two dogs, with sharp decrease in transmissibility rate as compared with pre-treatment condition. Altogether, Vectra®3D abrogated by >98% the potential Leishmania transmissibility by the examined pool of infected dogs over 1 month.


Asunto(s)
Enfermedades de los Perros , Insecticidas , Leishmania infantum , Leishmaniasis Visceral , Leishmaniasis , Phlebotomus , Animales , Perros , Guanidinas , Insecticidas/farmacología , Leishmaniasis/veterinaria , Leishmaniasis Visceral/veterinaria , Neonicotinoides , Nitrocompuestos , Permetrina/farmacología , Piridinas
7.
Microb Ecol ; 83(1): 202-215, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33758979

RESUMEN

Exposure to environmental stressors, an increasingly recurring event in natural communities due to anthropogenic-induced environmental change, profoundly impacts disease emergence and spread. One mechanism through which this occurs is through stress-induced immunosuppression increasing disease susceptibility, prevalence, intensity and reactivation in hosts. We experimentally evaluated how exposure to stressors affected both the physiology of avian hosts and the prevalence of the zoonotic bacteria Borrelia burgdorferi sensu lato (s.l.), in two model species-the blackbird Turdus merula and the robin Erithacus rubecula captured in the wild, using xenodiagnoses and analysis of skin biopsies and blood. Although exposure to stressors in captivity induced physiological stress in birds (increased the number of circulating heterophils), there was no evidence of increased infectivity to xenodiagnostic ticks. However, Borrelia detection in the blood for both experimental groups of blackbirds was higher by the end of the captivity period. The infectivity and efficiency of transmission were higher for blackbirds than robins. When comparing different methodologies to determine infection status, xenodiagnosis was a more sensitive method than skin biopsies and blood samples, which could be attributed to mild levels of infection in these avian hosts and/or dynamics and timing of Borrelia infection relapses and redistribution in tissues.


Asunto(s)
Grupo Borrelia Burgdorferi , Borrelia burgdorferi , Borrelia , Ixodes , Enfermedad de Lyme , Pájaros Cantores , Animales , Grupo Borrelia Burgdorferi/fisiología , Ixodes/microbiología , Enfermedad de Lyme/microbiología , Enfermedad de Lyme/veterinaria , Pájaros Cantores/microbiología
8.
Front Vet Sci ; 8: 667290, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34017871

RESUMEN

Infected dogs are considered the main domestic animal reservoirs for Leishmania infantum parasite. Infectiousness to competent phlebotomine vectors has been associated with many factors, the main being the severity of the disease exhibited by infected dogs. This study examines the relationship between different clinical parameters and the infectiousness to colonized Phlebotomus perniciosus sand flies having a blood meal on dogs. Data obtained in the present study come from an untreated group of Leishmania sick dogs submitted to xenodiagnosis for the evaluation of a spot on insecticide solution. Seventeen dogs were diagnosed as affected by leishmaniasis through clinical examination, immunofluorescence antibody test (IFAT) serology, and loop-mediated isothermal amplification (LAMP). The disease severity (clinical score) was staged by using a numeric value derived from eight clinical and parasitological parameters. Xenodiagnosis was performed on caged dogs exposed for 1.5 h to sand-fly bites. The following parameters related to sand flies were examined: blood feeding (% of blood engorged females), promastigote detection (% of promastigote-positive sand flies), promastigote burden, and the promastigote stage maturation (potential transmissibility rate). Statistical relationship between the clinical score and entomological parameters was investigated, as well as the possible correlation between each clinical and laboratory parameters and sand fly infection/infectivity. The severity of clinical score may influence the blood feeding by, and the probability of promastigote detection in, sand flies; skin lesions seem to be the main factor that influences the rate of blood feeding. Promastigote burden is related to IFAT titer, skin lesions, and clinical score. All entomological parameters are strongly related among them. This study confirms that both P. perniciosus infection and infectivity are influenced by a dog's clinical condition.

9.
Int Microbiol ; 24(2): 141-147, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33156443

RESUMEN

Direct test over the gut material from triatomine vectors and xenodiagnosis over mammalian hosts are classical techniques for Trypanosoma cruzi parasitological diagnosis. Nevertheless, negative results can be a source of uncertainty. Experimental models have allowed evaluating the tissue invasion of different strains of T. cruzi, but conventional techniques for tissue biopsies involve time-consuming and elaborated procedures and have low sensitivity. Gut material of collected triatomines (microscopically negative) (n = 114), material of mammal xenodiagnoses (microscopically negative) (n = 138), and biopsy material (microscopically negative) from experimentally infected animals (n = 34) with isolates from endemic areas of Chagas' disease from Venezuela were used for DNA extraction and PCR for the amplification of kinetoplast DNA (kDNA) and satellite DNA (sDNA) of T. cruzi. Positive PCR was observed in 53.6% of collected triatomine material, 15.8% of parasitological negative xenodiagnosis material, and 70.6% in biopsies, revealing underestimation by the parasitological tests and the valour of this analysis with preserved material. Anzoátegui was the state with the highest percentage of infection, and the triatomine species Rhodnius prolixus and Panstrongylus geniculatus had the highest percentages of infection. Didelphis marsupialis and Canis familiaris were the most infected by T. cruzi revealed by PCR of xenodiagnosis material. In addition, the PCR technique allowed demonstrating the invasion of T. cruzi in all tissues analyzed, constituting a molecular marker of tissue invasion.


Asunto(s)
Enfermedad de Chagas/parasitología , ADN Protozoario/genética , Didelphis/parasitología , Insectos Vectores/parasitología , Triatominae/parasitología , Trypanosoma cruzi/genética , Animales , Biopsia , Enfermedad de Chagas/diagnóstico , Perros , Humanos , Insectos Vectores/clasificación , Reacción en Cadena de la Polimerasa , Triatominae/clasificación , Trypanosoma cruzi/aislamiento & purificación , Xenodiagnóstico
10.
Microorganisms ; 8(9)2020 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-32962237

RESUMEN

The clinical manifestation of leishmaniases depends on parasite species, host genetic background, and immune response. Manifestations of human leishmaniases are highly variable, ranging from self-healing skin lesions to fatal visceral disease. The scope of standard model hosts is insufficient to mimic well the wide disease spectrum, which compels the introduction of new model animals for leishmaniasis research. In this article, we study the susceptibility of three Asian rodent species (Cricetulus griseus, Lagurus lagurus, and Phodopus sungorus) to Leishmania major and L. donovani. The external manifestation of the disease, distribution, as well as load of parasites and infectiousness to natural sand fly vectors, were compared with standard models, BALB/c mice and Mesocricetus auratus. No significant differences were found in disease outcomes in animals inoculated with sand fly- or culture-derived parasites. All Asian rodent species were highly susceptible to L. major. Phodopus sungorus showed the non-healing phenotype with the progressive growth of ulcerative lesions and massive parasite loads. Lagurus lagurus and C. griseus represented the healing phenotype, the latter with high infectiousness to vectors, mimicking best the character of natural reservoir hosts. Both, L. lagurus and C. griseus were also highly susceptible to L. donovani, having wider parasite distribution and higher parasite loads and infectiousness than standard model animals.

11.
Parasitol Int ; 77: 102121, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32283318

RESUMEN

Chagas disease is a serious problem of parasitic disease in the American continent, this zoonosis is caused by the flagellated protozoan known as Trypanosoma cruzi and transmitted through trypomastigotes present in the blood of sick hosts or in the faeces of the triatomines. Metacyclic trypomastigotes were detected in the faeca material of Triatoma pallidepennis maintained in the laboratory after the xenodiagnosis study performed on a patient with suspected Chagas disease, which allowed to administer treatment in a timely manner in the acute phase of this disease.


Asunto(s)
Enfermedad de Chagas/diagnóstico , Insectos Vectores/parasitología , Triatoma/parasitología , Xenodiagnóstico , Enfermedad Aguda , Adulto , Animales , Enfermedad de Chagas/tratamiento farmacológico , Heces/parasitología , Femenino , Humanos , México , Trypanosoma cruzi/genética , Trypanosoma cruzi/aislamiento & purificación , Zoonosis/transmisión
12.
Vet Parasitol ; 280: 109058, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32200198

RESUMEN

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.


Asunto(s)
Enfermedades de los Gatos/transmisión , Insectos Vectores/parasitología , Leishmania infantum/fisiología , Leishmaniasis Visceral/veterinaria , Psychodidae/parasitología , Animales , Brasil , Gatos , Femenino , Leishmaniasis Visceral/transmisión , Masculino
13.
Infect Genet Evol ; 78: 104062, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-31683004

RESUMEN

A key parameter in the transmission of vector-borne infections, including Chagas disease, is the ability of the different host species to transmit the parasite to the vector (infectiousness). Here, we determined infectiousness to the vector of Trypanosoma cruzi-seropositive humans examined by artificial xenodiagnosis (XD), established its relationship with T. cruzi DNA levels (a surrogate of intensity of parasitemia) quantified by real-time PCR (qPCR), and assessed whether infectiousness was associated with the body mass index (BMI), age, ethnic background and parasite genotype. XD was performed to 117 T. cruzi-seropositive residents from Pampa del Indio and parasite load was quantified in 81 of them. Using optical microscopy (OM) 33.6% of the seropositive people tested were infectious and this fraction nearly doubled (66.0%) when XD triatomines were examined by kDNA-PCR. The mean infectiousness (defined as the percentage of all infected triatomines detected by OM at any time point among the total number of insects examined by OM 30 days post-feeding) was 5.2%, and the mean parasite load was 0.51 parasite equivalents per ml. Infectiousness to the vector was associated negatively with age and BMI, and positively with the detection of parasitemia by kDNA-PCR, and parasite load by qPCR in bivariate analysis. Patients with a positive XD by OM exhibited a significantly higher mean parasite load. Using multiple regression, infectiousness was associated with parasite load (positively) and with the household presence of T. infestans and Qom ethnic group (negatively); no significant association was observed with age or its interaction with ethnicity. We did not find significant associations between identified DTUs and infectiousness or parasite load. Infectiousness was aggregated: 18% of the people examined by XD generated 80% of the infected triatomines. Detecting and treating the super-infectious fraction of the infected human would disproportionally impact on domestic transmission risks. Nonetheless, treatment of all eligible infected people who meet the inclusion criteria regardless of their parasitemia should be ensured to improve their prognosis.


Asunto(s)
Enfermedad de Chagas/transmisión , ADN de Cinetoplasto/genética , Triatominae/parasitología , Trypanosoma cruzi/patogenicidad , Adolescente , Adulto , Anciano , Animales , Anticuerpos Antiprotozoarios/metabolismo , Argentina , Índice de Masa Corporal , Enfermedad de Chagas/inmunología , Niño , Genotipo , Humanos , Persona de Mediana Edad , Carga de Parásitos , Reacción en Cadena en Tiempo Real de la Polimerasa , Población Rural , Trypanosoma cruzi/genética , Trypanosoma cruzi/inmunología , Xenodiagnóstico , Adulto Joven
14.
Int J Parasitol Parasites Wildl ; 11: 40-45, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31879594

RESUMEN

Visceral leishmaniasis caused by Leishmania donovani is regarded as mostly anthroponotic, but a role for animal reservoir hosts in transmission has been suggested in East Africa. Field studies in this region have shown the presence of this parasite in several mammalian species, including rodents of the genera Arvicanthis and Mastomys. Further, the natural reservoirs of Leishmania (Mundinia) sp. causing human cutaneous disease in Ghana, West Africa, are unknown. This study assessed the potential role of the Sub-Saharan rodents Arvicanthis neumanni, A. niloticus and Mastomys natalensis as hosts of L. donovani and L. sp. from Ghana, based on experimental infections of animals and xenodiagnoses. The distribution and load of parasites were determined post mortem using qPCR from the blood, skin and viscera samples. The attractiveness of Arvicanthis and Mastomys to Phlebotomus orientalis was tested by pair-wise comparisons. None of the animals inoculated with L. donovani were infectious to P. orientalis females, although, in some animals, parasites were detected by PCR even 30 weeks post infection. Skin infections were characterized by low numbers of parasites while high parasite burdens were present in spleen, liver and lymph nodes only. Therefore, wild Arvicanthis and Mastomys found infected with L. donovani, should be considered parasite sinks rather than parasite reservoirs. This is indirectly supported also by results of host choice experiments with P. orientalis in which females preferred humans over both Arvicanthis and Mastomys, and their feeding rates on rodents ranged from 1.4 to 5.8% only. Therefore, the involvement of these rodents in transmission of L. donovani by P. orientalis is very unlikely. Similarly, poor survival of Leishmania parasites in the studied rodents and negative results of xenodiagnostic experiments do not support the involvement of Arvicanthis and Mastomys spp. in the transmission cycle of L. sp. from Ghana.

15.
Acta Trop ; 200: 105167, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31513762

RESUMEN

It is not currently known which individuals with chronic Chagas disease (ChD) will develop cardiopathy in a determined period and which will be maintained asymptomatic with normal routine laboratory tests all their lives. The parasite burden is a factor that could explain this different evolution. The objective of this study was to quantify Trypanosoma cruzi burden by real-time PCR in blood (qPCR-B) and dejections of triatomines fed by xenodiagnosis (qPCR-XD) in 90 individuals with chronic ChD untreated, classified according to XD results and the presence or absence of cardiopathy. All individuals came from hyperendemic areas of Chile and participated in the study under Informed Consent. The standard qPCR curves for qPCR-B and qPCR-XD were elaborated with a mixture of known concentrations of T. cruzi strains, performing DNA serial dilutions (1/10) with a dynamic range between 105 and 10-1 parasite equivalents/mL. The TaqManⓇ detection system was applied in a Stratagene Mx3000P thermocycler (Agilent Technologies, USA) with cruzi 1 and cruzi 2 satellite primers. 22.2% and 15.6% of cases with cardiopathy or without cardiopathy were XD positive. There was no significant difference between the groups. The positivity of qPCR-B and qPCR-XD in the positive XD group was 82.35% and 100%, respectively, while in the negative XD group was 55.26% and 42.10%, respectively. A superior qPCR value in chronic ChD patients with and without cardiopathy was determined for qPCR in cases with positive XD and positive qPCR-XD. The receiver operating characteristic (ROC) curve analyses show better accuracy for detecting parasite burden (area under the curve, AUC) for qPCR-XD in comparison to qPCR-B. That is to say, major performance in DNA samples obtained of positive XD (gold standard for viable T. cruzi) detected and quantified by qPCR-XD. A high percentage of cases with XD and qPCR-XD positive (80-100%) have result concordant with qPCR-B. In absence of XD, future challenges are especially related to the low parasitic load of chronic ChD patients treated with trypanocidal drugs and post-therapy parasitological evaluations by qPCR-B. Finally, no statistically significant differences were found between presence or absence of cardiopathy and XD, qPCR-B or qPCR-XD.


Asunto(s)
Enfermedad de Chagas/complicaciones , Enfermedad de Chagas/parasitología , Cardiopatías/etiología , Carga de Parásitos , Triatoma/parasitología , Trypanosoma cruzi/aislamiento & purificación , Xenodiagnóstico/métodos , Adulto , Factores de Edad , Anciano , Animales , Enfermedad de Chagas/sangre , Enfermedad de Chagas/epidemiología , Chile/epidemiología , Enfermedad Crónica/epidemiología , Pruebas Diagnósticas de Rutina , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Tripanocidas , Trypanosoma cruzi/genética
16.
Trends Parasitol ; 35(8): 590-592, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31266711

RESUMEN

Post-kala-azar dermal leishmaniasis (PKDL) is a parasitic skin infection which can occur after visceral leishmaniasis (VL). Recent xenodiagnosis studies (Mondal et al., Clin. Infect. Dis., 2018) have uncovered the infectiousness of PKDL. When including this in a transmission model, PKDL cases appear as an important reservoir of infection, likely frustrating the VL elimination efforts on the Indian subcontinent.


Asunto(s)
Leishmaniasis Cutánea , Leishmaniasis Visceral , Psychodidae , Animales
17.
Int J Parasitol ; 49(6): 417-421, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30940471

RESUMEN

Imported cases of anthroponotic cutaneous leishmaniasis due to Leishmania tropica are increasingly documented in Europe. We investigated the ability of Phlebotomus perniciosus, a competent vector of Leishmania infantum widespread in southwestern Europe, to support the growth and transmissibility of an Asian strain of L. tropica recently isolated from a refugee. Parasite growth behavior was investigated in laboratory-reared sand flies fed artificially with promastigotes as well as in sand flies infected after biting on footpad lesions induced in hamsters by promastigote inoculation. The evolution of infection was checked by gut microscopy and quantitative real-time PCR, and it was found to be similar between promastigote- and amastigote-initiated infections. In 80% of infected sand flies, despite survival and flourishing growth of promastigotes after blood digestion and defecation, either the parasites died, or failed to migrate to the foregut and/or to mature into infective forms. However, in the remaining 20% L. tropica developed into abundant metacyclic promastigotes. The quantitative real-time PCR assay detected variable loads of gut promastigotes irrespective of morphological evidence of viability or progressive/final death. Parasite transmissibility was investigated by exposing naive hamsters to P. perniciosus previously infected on chronic lesions induced in hamsters which survived to take a second blood meal. Two months post exposure, lesions developed in skin sites bitten by sand flies confirmed to harbor metacyclic promastigotes; in the following months, the presence of viable and transmissible L. tropica parasites in lesions was demonstrated by xenodiagnosis assays. Our findings support the hypothesis that, in particular epidemiological situations, P. perniciosus may play the role of an occasional L. tropica vector.


Asunto(s)
Insectos Vectores/parasitología , Leishmania tropica/fisiología , Leishmaniasis Cutánea/transmisión , Phlebotomus/parasitología , Animales , Asia , Cricetinae , Europa (Continente) , Femenino , Humanos , Insectos Vectores/clasificación , Leishmania tropica/genética , Leishmania tropica/crecimiento & desarrollo , Leishmania tropica/aislamiento & purificación , Mesocricetus , Phlebotomus/clasificación , Reacción en Cadena en Tiempo Real de la Polimerasa , Refugiados
18.
Int J Parasitol Parasites Wildl ; 8: 118-126, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30740304

RESUMEN

Cutaneous leishmaniasis caused by Leishmania major is a typical zoonosis circulating in rodents. In Sub-Saharan Africa the reservoirs remain to be identified, although L. major has been detected in several rodent species including members of the genera Arvicanthis and Mastomys. However, differentiation of true reservoir hosts from incidental hosts requires in-depth studies both in the field and in the laboratory, with the best method for testing the infectiousness of hosts to biting vectors being xenodiagnosis. Here we studied experimental infections of three L. major strains in Arvicanthis neumanni, A. niloticus and Mastomys natalensis; the infections were initiated either with sand fly-derived or with culture-derived Leishmania promastigotes. Inoculated rodents were monitored for several months and tested by xenodiagnoses for their infectiousness to Phlebotomus duboscqi, the natural vector of L. major in Sub-Saharan Africa. The distribution and load of parasites were determined post mortem using qPCR from the blood, skin and viscera samples. The attractiveness of Arvicanthis and Mastomys to P. duboscqi was tested by pair-wise comparisons. Three L. major strains used significantly differed in infectivity: the Middle Eastern strain infected a low proportion of rodents, while two Sub-Saharan isolates (LV109, LV110) infected a high percentage of animals and LV110 also produced higher parasite loads in all host species. All three rodent species maintained parasites of the LV109 strain for 20-25 weeks and were able to infect P. duboscqi without apparent health complications: infected animals showed only temporary swellings or changes of pigmentation at the site of inoculation. However, the higher infection rates, more generalized distribution of parasites and longer infectiousness period to sand flies in M. natalensis suggest that this species plays the more important reservoir role in the life cycle of L. major in Sub-Saharan Africa. Arvicanthis species may serve as potential reservoirs in seasons/periods of low abundance of Mastomys.

19.
Parasit Vectors ; 12(1): 79, 2019 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-30736866

RESUMEN

BACKGROUND: Visceral leishmaniasis (VL) is an infectious disease with a variety of clinical signs. The main form of parasite transmission to humans and other mammalian hosts is through the bite of infected arthropod females with Lutzomyia longipalpis serving as the main vector in the Americas. Dogs are the main urban domestic reservoirs of the parasite and the main source of vector infection due to their high prevalence in endemic areas and the large number of parasites in the skin of infected animals. Although miltefosine has been used in Europe since 2002 for treatment of VL infected dogs, in the Americas the treatment of dogs has not been recommended. Therefore, this study aimed to evaluate efficacy of miltefosine observing a reduction of clinical signs in infected dogs and the infectiveness to the vector by Leishmania (L.) infantum. METHODS: To our knowledge, this is the first controlled study using qPCR and xenodiagnosis to evaluate the efficacy of miltefosine (Milteforan®, Virbac) as a single treatment in Brazil. Thirty-five adult dogs with canine visceral leishmaniasis (CVL), confirmed by clinical and laboratory tests, were included in this study. They received miltefosine at a dose of 2 mg/kg every 24 h for 28 days. The dogs were observed over a three-month period, during which clinical evaluations based on a scoring system were conducted at pre-established times. Parasite load was assessed by cytology and real-time polymerase chain reaction (qPCR). Transmissibility to the vector was evaluated by xenodiagnosis. RESULTS: At the end of the period, the following were observed: (i) the remission of clinical signs with a reduction in clinical scores for 94.2% of the animals; (ii) a statistically significant reduction (98.7%) in parasitic load by qPCR; and (iii) a reduction in infectivity to sand flies. After treatment, 74.2% of the animals remained or had become non-infectious. CONCLUSIONS: Our study indicates that the use of miltefosine administered orally for 4 weeks contributes to a clinical improvement and reduction in infectivity of dogs to L. infantum.


Asunto(s)
Antiprotozoarios/administración & dosificación , Enfermedades de los Perros/tratamiento farmacológico , Leishmania infantum/efectos de los fármacos , Leishmaniasis Visceral/veterinaria , Fosforilcolina/análogos & derivados , Administración Oral , Animales , Enfermedades de los Perros/parasitología , Perros , Femenino , Insectos Vectores/parasitología , Leishmaniasis Visceral/tratamiento farmacológico , Leishmaniasis Visceral/parasitología , Masculino , Carga de Parásitos/veterinaria , Fosforilcolina/administración & dosificación , Psychodidae/parasitología , Reacción en Cadena en Tiempo Real de la Polimerasa/veterinaria , Piel/parasitología , Resultado del Tratamiento , Xenodiagnóstico/veterinaria
20.
AAS Open Res ; 2: 164, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-32510036

RESUMEN

Background: Major constraints to camel production include pests and diseases. In northern Kenya, little information is available about disease pathogens circulating in one-humped camels ( Camelus dromedarius) or their possible transmission by the camel haematophagous ectoparasite, Hippobosca camelina, commonly known as camel ked or camel fly. This study aimed to: (i) identify the presence of potentially insect-vectored pathogens in camels and camel keds, and (ii) assess the potential utility of keds for xenodiagnosis of camel disease pathogens that they may not vector. Methods: In Laisamis, northern Kenya, camel blood samples (n = 249) and camel keds (n = 117) were randomly collected from camels. All samples were screened for trypanosomal and camelpox DNA by PCR, and for Anaplasma, Ehrlichia, Brucella, Coxiella, Theileria, and Babesia by PCR coupled with high-resolution melting (PCR-HRM) analysis. Results: In camels, we detected Trypanosoma vivax (102/249) (41%), Trypanosoma evansi (3/249) (1.2%), and " Candidatus Anaplasma camelii" (137/200) (68.5%). In camel keds, we also detected T. vivax (53/117) (45.3%), T. evansi (3/117) (2.56%), Trypanosoma melophagium (1/117) (0.4%), and " Candidatus Anaplasma camelii" (19/117) (16.24 %). Piroplasms ( Theileria spp. and Babesia spp.), Coxiella burnetii, Brucella spp., Ehrlichia spp., and camel pox were not detected in any samples. Conclusions: This study reveals the presence of epizootic pathogens in camels from northern Kenya. Furthermore, the presence of the same pathogens in camels and in keds collected from sampled camels suggests the potential use of these flies in xenodiagnosis of haemopathogens circulating in camels.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA