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1.
Acta Trop ; 243: 106930, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37098356

RESUMEN

Chagas disease is caused by the protozoan Trypanosoma cruzi, which parasitizes many mammals, including humans. Its vectors are blood-feeding hematophagous triatomine insects of different species, which vary according to the geographical area. One of the 17 neglected diseases targeted by the World Health Organization, Chagas disease is endemic to the Americas, but has spread to other countries due to human migratory movements. In this study, we describe the epidemiological dynamics of Chagas disease in an endemic area, considering the main transmission mechanisms and the demographic effects of birth, mortality, and human migration in this phenomenon. We apply mathematical models as a methodological approach to simulate the interactions between reservoirs, vectors, and humans using a system of ordinary differential equations. The results show that the Chagas disease control measures currently in place cannot be relaxed without endangering the progress achieved to date.


Asunto(s)
Enfermedad de Chagas , Triatoma , Trypanosoma cruzi , Animales , Humanos , Insectos Vectores , Modelos Teóricos , Mamíferos
2.
Acta Trop ; 243: 106929, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37086936

RESUMEN

Geographic isolation and strict control limits in border areas have kept Chile free from various pathogens, including Flavivirus. However, the scenario is changing mainly due to climate change, the reintroduction of more aggressive mosquitoes, and the great wave of migration of people from endemic countries in recent years. Hence, it is necessary to surveillance mosquitoes to anticipate a possible outbreak in the population and take action to control it. This study aimed to investigate the presence of Flavivirus RNA by molecular tools with consensus primers in mosquitoes collected in the extreme north and central Chile. From 2019 to 2021, a prospective study was carried out in localities of Northern and part of Central Chile. Larvae, pupae, and adults of mosquitoes were collected in rural and urban sites in each locality. The collected samples were pooled by species and geographical location and tested using RT-PCR and RT-qPCR to determine presence of Flavivirus. 3085 specimens were collected, the most abundant specie Culex quinquefasciatus in the North and Aedes (Ochlerotatus) albifasciatus in the Center of Chile. Both genera are associated with Flavivirus transmission. However, PCR and RT-PCR did not detect Flavivirus RNA in the mosquitoes studied. These negative results indicate we are still a free Flavivirus country, which is reaffirmed by the non-existence of endemic human cases. Despite this, routine surveillance of mosquitoes and the pathogens they carry is highly recommended to evaluate each area-specific risk of vector-borne transmission.


Asunto(s)
Aedes , Culex , Culicidae , Flavivirus , Animales , Humanos , Flavivirus/genética , Estudios Prospectivos , Mosquitos Vectores , Aedes/genética , Culex/genética , ARN , Filogenia
3.
Emerg Infect Dis ; 29(2)2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36692864

RESUMEN

We report a case of Dirofilaria immitis nematode infection in a dog imported from Venezuela that had been living for 2 years in Santiago, Chile, where this parasite had not been reported before. Our findings warrant surveillance for all dogs imported to Chile, given that suitable conditions exist for establishing this parasite.


Asunto(s)
Dirofilaria immitis , Dirofilaria repens , Dirofilariasis , Enfermedades de los Perros , Animales , Perros , Dirofilariasis/diagnóstico , Dirofilariasis/epidemiología , Dirofilariasis/parasitología , Chile/epidemiología , Venezuela/epidemiología , Enfermedades de los Perros/diagnóstico , Enfermedades de los Perros/epidemiología , Enfermedades de los Perros/parasitología
4.
Front Vet Sci ; 10: 1334832, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38260205

RESUMEN

Climate change, competent vectors, and reservoir animals are the main factors for developing vector-borne zoonotic diseases. These diseases encompass a significant and widespread category of pathogens (e.g., viruses, bacteria, protozoa, and helminths) transmitted by blood-feeding arthropods, including ticks, fleas, lice, triatomines, mosquitoes, sandflies, and blackflies. In Chile, several studies have explored the role of dogs as reservoirs of vector-borne pathogens; however, there is a lack of research investigating the presence of pathogens in arthropods. Specifically, within the order Diptera, limited knowledge exists regarding their roles as carriers of pathogens. This study aimed to examine the presence of zoonotic filarial nematodes in mosquitoes and dogs within a previously unstudied semi-rural area of Central Chile. Two hundred samples of dog blood and seven hundred and twenty-four mosquitoes were collected during 2021-2022 and studied for filarial nematodes by PCR. The prevalence of microfilaremic dogs detected by Knott's test was 7.5%, with Acanthocheilonema reconditum being the only species identified. Aedes (Ochlerotatus) albifasciatus was the most abundant mosquito species collected, and 15 out of 65 pools were positive for filarial nematodes. Among these pools, 13 tested positive for Acanthocheilonema reconditum, and two tested positive for Setaria equina through PCR. Additionally, five Culex pipiens specimens were positive for Acanthocheilonema reconditum. Despite the absence of zoonotic filarial species, these findings underscore the significance of monitoring pathogens in mosquitoes and animal hosts and continued research into the dynamics of vector-borne diseases, particularly in unexplored regions.

5.
Acta Trop ; 226: 106230, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34801478

RESUMEN

Dirofilaria repens is a nematode affecting domestic and wild canids, transmitted by several species of mosquitoes of different genera. It usually causes a non-pathogenic subcutaneous infection in dogs and is the principal agent of human dirofilariasis in the Old World. The geographic distribution of D. repens is changing rapidly, and several factors contribute to the spread of the infection to non-endemic areas. A mathematical model for transmission of Dirofilaria spp. was built, using a system of ordinary differential equations that consider the interactions between reservoirs, vectors, and humans. The transmission simulations of D. repens were carried out considering a projection in time, with intervals of 15 and 100 years. For the dynamics of the vector, seasonal variations were presented as series with quarter periodicity during the year. The results of the simulations highlight the peak of contagions in the reservoir and in humans, a product of the action of the vector when it remains active throughout the year. A 300% infection increase in the reservoir was observed during the first decade and remains present in the population with a representative number of cases. When the vector maintains its density and infectivity during the year, the incidence of the infection in humans increases. Accumulated cases amount to 45 per 100,000 inhabitants, which corresponds to a cumulative incidence of 0.05%, in 85 years. This indicates that early prevention of infection in canids would significantly reduce the disease, also reducing the number of accumulated cases of human dirofilariasis by D. repens. The interaction between the simulations generated by the model highlights the sensitivity of the epidemiological curve to the periodicity of seasonality, reaffirming the hypothesis of the probability of movement of the zoonotic disease to non-endemic areas, due to climate change.


Asunto(s)
Dirofilaria immitis , Dirofilaria repens , Dirofilariasis , Enfermedades de los Perros , Animales , Cambio Climático , Dirofilariasis/epidemiología , Perros , Modelos Teóricos , Mosquitos Vectores
6.
Infect Genet Evol ; 59: 7-15, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29413886

RESUMEN

Leishmaniasis, a public health problem in Tunisia, are diseases caused by different Leishmania species. Cutaneous leishmaniasis is present from the North to the South under different forms, due to Leishmania (L.) major, L. infantum or L. tropica. Whereas, Psammomys (P.) obesus is the confirmed reservoir host of L. major, those of L. tropica and dermotropic L. infantum wait to be identified. Importantly, P. vexillaris species have been recently highlighted; however, no studies have been carried out to explore its potential role in leishmaniasis epidemiology. Seventy two rodents were collected from Central and South-West of Tunisia between 2007 and 2010. Using several methods, 43 animals were identified as P. obesus and 29 as P. vexillaris. Leishmania kinetoplast DNA was detected in liver samples by real-time PCR in 18 P. obesus and in 8 P. vexillaris. Then, the direct sequencing of the amplified internal transcribed spacer 1, allowed the identification of L. infantum DNA in five P. obesus and in three P. vexillaris, as well as L. tropica DNA in three other P. vexillaris. Whereas, PCR fluorescent fragment length analysis of the 7 spliced leaders, allowed identifying L. major among infected P. obesus and P. vexillaris, and interestingly co-infection (L. major/L. infantum) among two P. obesus. We report here for the first time, the infection of P. obesus, from Central Tunisia, by L. infantum. Suggesting that P. obesus the known reservoir host of L. major, may also serve as reservoir host for L. infantum and thus play a role in the spread of sporadic cutaneous or visceral leishmaniasis in this region. Of equal importance, this work establish for the first time, the natural infection of P. vexillaris by different Leishmania species, suggesting its potential epidemiological role as reservoir host.


Asunto(s)
Reservorios de Enfermedades/parasitología , Gerbillinae/parasitología , Leishmania , Leishmaniasis/epidemiología , Leishmaniasis/parasitología , Animales , ADN Protozoario/genética , Leishmania/clasificación , Leishmania/genética , Hígado/parasitología , Epidemiología Molecular , Túnez/epidemiología
7.
Blood Transfus ; 16(2): 130-136, 2018 02.
Artículo en Inglés | MEDLINE | ID: mdl-28488962

RESUMEN

BACKGROUND: In the Balearic Islands, as in other areas of the Mediterranean basin, there is a significant proportion of asymptomatic Leishmania (L.) infantum-infected blood donors, who may represent an important threat to transfusion safety. The Balearic Islands blood bank, located in an area endemic for L. infantum, carried out a study of donors and patients to investigate the impact of this infectious disease on blood safety in the region. MATERIALS AND METHODS: Twenty asymptomatic Leishmania-infected blood donors were followed-up between 2008 and 2011 to investigate the evolution of Leishmania infection in asymptomatic carriers. Their blood was periodically tested for anti-Leishmania antibodies by western blot and for Leishmania DNA by quantitative polymerase chain reaction (qPCR). Additionally, the prevalence of L. infantum infection was investigated in a group of 68 multiply transfused patients to ascertain the risk of transfusion-transmitted leishmaniasis (TTL) in the region, taking into account regular blood component production practices such as pre-storage leucodepletion and pathogen reduction technology. RESULTS: All 20 donors remained asymptomatic over the study period (2008-2011). Most donors had repeatedly positive qPCR results, either persistently or intermittently, but showed no symptoms of Leishmaniasis. Levels of parasitaemia were remarkably low in asymptomatic donors, with values ≤1 parasite/mL. Despite multiple transfusions received over 15 years, no transfused patient studied was infected with L. infantum. DISCUSSION: L. infantum-infected donors can remain asymptomatic for at least 3 years. In our region, no cases of TTL were detected, despite an active search in multiply transfused patients. This seems to be related to two independent variables: (i) a low concentration of the parasite in the peripheral blood of asymptomatic carriers and (ii) the application of methods with proven efficacy against TTL, such as leucodepletion and pathogen reduction technology.


Asunto(s)
Bancos de Sangre , Donantes de Sangre , Transfusión Sanguínea , ADN Protozoario/sangre , Selección de Donante , Leishmania infantum , Leishmaniasis Visceral , Adulto , Enfermedades Endémicas , Femenino , Humanos , Leishmaniasis Visceral/sangre , Leishmaniasis Visceral/transmisión , Masculino , Persona de Mediana Edad , Reacción en Cadena en Tiempo Real de la Polimerasa , España
8.
Int J Food Microbiol ; 261: 89-94, 2017 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-28554526

RESUMEN

The extensive presence of anisakids in fish for human consumption has become a problem of food safety and quality. The aim of this study was to develop and assess the performance of a quantitative SYBR Green qPCR assay for the detection and quantification of Anisakis DNA in fish by-products. L3 nematode larvae of A. simplex (s.l.) (n=510), A. physeteris (n=3), Hysterothylacium sp. (n=10) and Pseudoterranova sp. (n=1), isolated from blue whiting, horse mackerel and monkfish, were used for the optimization of the molecular assay. In addition, molecularly typed larvae of A. simplex (s.s.) (n=10) and A. pegreffii (n=5) of the complex A. simplex (s.l.) were used for the specificity assay. Primers targeting the mitochondrial cytochrome c oxidase subunit II gene (COII) were selected. Analytical sensitivity and reproducibility were evaluated in a food matrix consisting of commercial fish-derived food spiked with larvae of A. simplex (s.l.). The assay proved to be specific for the three analyzed Anisakis species. A high reproducibility and sensitivity was detected, with a 95% limit of detection (LOD) of 0.30ng (95%CI 0.15-1.50) of A. simplex (s.l.) DNA per gram of food matrix and an operative LOD of 1.50ng after a PROBIT analysis. The assay was applied to study the presence of Anisakis in four types of processed commercial food, namely crab sticks, "gulas", croquettes and burgers. Overall, 180 food samples from 15 commercial brands were studied, detecting Anisakis DNA in over half of them. The analyzed surimi-based products, "gulas" and crab sticks, showed the highest Anisakis burden (5.86±0.69 and 4.68±0.73ng of Anisakis DNA per gram of food, respectively). Our results indicate that the optimized SYBR Green qPCR technique is an accurate and sensitive method that may improve detection of Anisakis in fresh and processed products.


Asunto(s)
Anisakiasis/parasitología , Anisakis/aislamiento & purificación , Contaminación de Alimentos/análisis , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Alimentos Marinos/parasitología , Animales , Anisakis/clasificación , Anisakis/genética , Parasitología de Alimentos , Inocuidad de los Alimentos , Humanos , Perciformes/parasitología , Reproducibilidad de los Resultados
9.
Transfusion ; 57(6): 1440-1447, 2017 06.
Artículo en Inglés | MEDLINE | ID: mdl-28419477

RESUMEN

BACKGROUND: The parasitic Chagas disease is caused by the protozoan Trypanosoma cruzi, which is mainly transmitted by insect vectors. Other infection routes, both in endemic and in nonendemic areas, include organ and marrow transplantation, congenital transmission, and blood transfusion. Asymptomatic chronic chagasic individuals may have a low and transient parasitemia in peripheral blood and, consequently, they can unknowingly transmit the disease via blood transfusion. Riboflavin and ultraviolet (UV) light pathogen reduction is a method to reduce pathogen transfusion transmission risk based on damage to the pathogen nucleic acids. STUDY DESIGN AND METHODS: In this study, we tested the effectiveness of this technology for the elimination of T. cruzi parasites in artificially contaminated whole blood units (WBUs) and thus for decreasing the risk of T. cruzi transfusion transmission. The contaminated WBUs were leukoreduced by filtration and treated with riboflavin and UV light. The level of pathogen reduction was quantified by a real-time polymerase chain reaction (qPCR) and a real-time reverse transcription-polymerase chain reaction (RT-qPCR) as a viability assay. RESULTS: The RNA (cDNA) quantification of the parasites showed a more than 99% reduction of viable T. cruzi parasites after leukoreduction and a complete reduction (100%) after the riboflavin and UV light treatment. CONCLUSION: Riboflavin and UV light treatment and leukoreduction used in conjunction appears to eliminate significant amounts of viable T. cruzi in whole blood. Both strategies could complement other blood bank measures already implemented to prevent the transmission of T. cruzi via blood transfusion.


Asunto(s)
Procedimientos de Reducción del Leucocitos/métodos , Riboflavina/farmacología , Trypanosoma cruzi/efectos de los fármacos , Trypanosoma cruzi/efectos de la radiación , Rayos Ultravioleta , Conservación de la Sangre/métodos , Enfermedad de Chagas/prevención & control , Trypanosoma cruzi/patogenicidad
10.
Transfusion ; 56(9): 2233-8, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-27321651

RESUMEN

BACKGROUND: Platelets (PLTs) are the blood component most frequently involved in Trypanosoma cruzi transfusion transmission cases reported in the literature, although whole blood (WB) and red blood cells (RBCs) have also been incriminated. However, there is little knowledge of the parasite distribution among blood components. STUDY DESIGN AND METHODS: The aim of this study was to investigate in which blood component T. cruzi parasites concentrate the most, after fractionating artificially T. cruzi-infected WB. The T. cruzi parasite load was studied by a specific quantitative real-time polymerase chain reaction (qPCR) in WB, buffy coat (BC), PLT concentrates, RBCs before and after leukoreduction, and plasma (PL). RESULTS: The parasite load in WB experimentally infected with 1.5 × 10(6) parasites (2.78 × 10(3) parasite equivalents/mL) was unevenly distributed among the separated blood components. The highest level was found in the BC (6.94 × 10(3) parasite equivalents/mL) and RBCs before leukoreduction by filtration (2.51 × 10(3) parasite equivalents/mL), after which RBCs presented a 99.9% reduction in parasite levels. Both PL and PLTs, partially leukoreduced by centrifugation but nonfiltered, had low parasite levels, the lowest concentration being in PL. CONCLUSIONS: The highest parasite concentration was detected in the BC, followed by RBCs before leukoreduction. There is a notable risk of transfusion-transmitted Chagas disease associated with nonleukoreduced RBCs. Leukoreduction may be an effective prevention strategy for transfusion-transmitted T. cruzi infection, especially in endemic countries and in nonendemic countries with a high rate of immigration from Latin America.


Asunto(s)
Transfusión de Componentes Sanguíneos/normas , Eritrocitos/parasitología , Transfusión de Plaquetas/efectos adversos , Trypanosoma cruzi/aislamiento & purificación , Transfusión de Componentes Sanguíneos/efectos adversos , Enfermedad de Chagas/sangre , Humanos , Carga de Parásitos , Transfusión de Plaquetas/normas , Reacción en Cadena en Tiempo Real de la Polimerasa
12.
Am J Trop Med Hyg ; 94(6): 1282-9, 2016 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-27139452

RESUMEN

Molecular techniques based on real-time polymerase chain reaction (qPCR) allow the detection and quantification of DNA but are unable to distinguish between signals from dead or live cells. Because of the lack of simple techniques to differentiate between viable and nonviable cells, the aim of this study was to optimize and evaluate a straightforward test based on propidium monoazide (PMA) dye action combined with a qPCR assay (PMA-qPCR) for the selective quantification of viable/nonviable epimastigotes of Trypanosoma cruzi PMA has the ability to penetrate the plasma membrane of dead cells and covalently cross-link to the DNA during exposure to bright visible light, thereby inhibiting PCR amplification. Different concentrations of PMA (50-200 µM) and epimastigotes of the Maracay strain of T. cruzi (1 × 10(5)-10 parasites/mL) were assayed; viable and nonviable parasites were tested and quantified by qPCR with a TaqMan probe specific for T. cruzi. In the PMA-qPCR assay optimized at 100 µM PMA, a significant qPCR signal reduction was observed in the nonviable versus viable epimastigotes treated with PMA, with a mean signal reduction of 2.5 logarithm units and a percentage of signal reduction > 98%, in all concentrations of parasites assayed. This signal reduction was also observed when PMA-qPCR was applied to a mixture of live/dead parasites, which allowed the detection of live cells, except when the concentration of live parasites was low (10 parasites/mL). The PMA-qPCR developed allows differentiation between viable and nonviable epimastigotes of T. cruzi and could thus be a potential method of parasite viability assessment and quantification.


Asunto(s)
Azidas/química , Propidio/análogos & derivados , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Trypanosoma cruzi/aislamiento & purificación , Trypanosoma cruzi/fisiología , Humanos , Propidio/química , Sensibilidad y Especificidad , Trypanosoma cruzi/química
13.
Transfusion ; 56 Suppl 1: S45-51, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27001361

RESUMEN

In the Balearic Islands, as in other areas in southern Europe, there are a significant proportion of asymptomatic Leishmania infantum-infected blood donors. Theoretically, these donors may represent an important challenge for blood transfusion safety. However, despite an active search of multiply transfused patients, there have been, so far, no cases of transfusion-transmitted leishmaniasis (TTL) in our region. On the other hand, there is scarce evidence of the TTL in the literature. A review of asymptomatic Leishmania-infected blood donors' studies in endemic areas and TTL reports published in the English literature were performed, to ascertain the factors that determine the real risk of transfusion transmission of Leishmania.


Asunto(s)
Transfusión Sanguínea , Patógenos Transmitidos por la Sangre , Leishmania infantum , Leishmaniasis Visceral , Donantes de Sangre , Femenino , Humanos , Leishmaniasis Visceral/sangre , Leishmaniasis Visceral/epidemiología , Leishmaniasis Visceral/transmisión , Masculino , Factores de Riesgo , España/epidemiología
14.
Transfusion ; 55(6): 1249-55, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25683267

RESUMEN

BACKGROUND: According to the reported cases of transfusion-acquired Trypanosoma cruzi infection, the risk of T. cruzi transfusion transmission appears to be higher with platelet (PLT) products than with other blood components. The aim of this study was to investigate by quantitative real-time polymerase chain reaction (qPCR) the parasitic load detected in leukoreduced plasma and PLT concentrates collected by apheresis from seropositive T. cruzi blood donors and compare them with peripheral whole blood (WB). STUDY DESIGN AND METHODS: During 2011 to 2013, a prospective study was carried out in a group of blood donors originating from Chagas-endemic areas but who are now living on the island of Majorca, Spain. Leukoreduced plasma and PLT concentrates were collected by apheresis from seropositive blood donors with detectable parasitemias in peripheral WB. RESULTS: Seropositivity was found in 23 of 1201 donors studied (1.9%), and T. cruzi DNA with less than 1 parasite equivalent/mL was detected in peripheral WB in 60.86% (14 of 23) of these. The study in blood components obtained by apheresis from these donors showed that T. cruzi DNA with a mean ± SD parasitic load of 5.33 ± 6.12 parasite equivalents/mL was detected in 100% of the PLT concentrate samples. Parasite DNA was undetectable in the extract taken from plasma collected from donors with a positive qPCR in peripheral WB. CONCLUSION: The higher parasitic load found in PLT concentrates compared to plasma and peripheral WB would explain the higher transfusion transmission risk of Chagas disease associated with PLT transfusions described in the reported cases of transfusion-acquired T. cruzi infection.


Asunto(s)
Donantes de Sangre , Plaquetas/parasitología , Enfermedad de Chagas/parasitología , ADN Protozoario/sangre , Emigrantes e Inmigrantes , Parasitemia/parasitología , Trypanosoma cruzi/aislamiento & purificación , Adulto , Enfermedad de Chagas/sangre , Enfermedad de Chagas/epidemiología , Enfermedades Endémicas , Humanos , Procedimientos de Reducción del Leucocitos , Plaquetoferesis/instrumentación , Reacción en Cadena en Tiempo Real de la Polimerasa , América del Sur/etnología , España/epidemiología , Trypanosoma cruzi/genética
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