Surveillance of phlebotomine fauna and Didelphis marsupialis (Didelphimorphia: Didelphidae) infection in an area highly endemic for visceral leishmaniasis in Colombia

Phlebotomine sand flies (Diptera: Psychodidae, Phlebotominae): Diversity of potential Leishmania vectors in northern Colombia

Phlebotomine sand flies are critical vectors of Leishmania parasites, impacting public health significantly. This study focused on assessing the diversity of sand flies in a rural area of El Carmen de Bolívar Municipality, northern Colombia, employing rarefaction curves and Hill numbers to understand potential vector communities and inform environmental management. From January 2018 to April 2019 (five samplings), sand flies were collected using CDC light traps with blue LED in domestic/peridomestic/sylvatic ecotopes, identifying species per Young and Duncan (1994) and Galati (2003). Hill numbers provided diversity estimates across samples, while Principal Component Analysis correlated with environmental factors with phlebotomine species presence and abundance. 8,784 phlebotomine individuals were collected; 56.4 % females and 43.6% males (ratio 3:2). These individuals belonged to eight species: Pintomyia evansi, Psychodopygus panamensis, Lutzomyia gomezi, Micropygomyia cayennensis, Evandromyia dubitans, Psathyromyia aclydifera, Pintomyia serrana, and Pintomyia rangeliana; with Pi. evansi being the most abundant species (74.39 %; 6,530 exemplars). The ANOVA showed no significant differences between phlebotomine sand flies abundances across ecotopes (p = 0.018). Species of epidemiological relevance as Pi. evansi and Lu. gomezi not show a positive correlation with environmental variables evaluated, only Ps. panamensis was positively correlated with precipitation. However, the study emphasizes the need for a continuous sand fly monitoring and research to enhance leishmaniasis control strategies, highlighting the necessity to expand knowledge on phlebotomine diversity and environmental interactions to understand vector ecology and disease dynamics better.

Phlebotomine (Diptera: Psychodidae) species and their blood meal sources in a new leishmaniasis focus in Los Montes de María, Bolívar, in northern Colombia

Introduction. El Alférez, a village in Los Montes de María (Bolívar, Colombia) and a macro-focus of leishmaniasis, recorded its first case in 2018, evidencing changes in the distribution and eco-epidemiology of the disease, although interactions between vectors and local fauna remain unknown. Objective. To evaluate the diversity of sandflies and their blood meal sources in the community of El Alférez in the municipality of El Carmen de Bolívar (Bolívar, Colombia). Materials and methods. In 2018, sandflies were collected using LED-based light traps in domestic, peridomestic, and sylvatic ecotopes and identified at the species level. Multiplex polymerase chain reaction targeting the mitochondrial cytochrome B gene was used to analyze blood from the digestive tract. Results. Lutzomyia evansi was the most abundant species (71.85%; n = 485/675), followed by Lu. panamensis, Lu. gomezi, Lu. trinidadensis, Lu. dubitans, Lu. abonnenci, and Lu.aclydifera. Twenty-five percent of the species had blood meals from Canis familiaris (36.00%; n = 9/25), Ovis aries (36.00%; n=9:/25), Bos taurus (24.00%; n = 6/25), Sus scrofa (20.00%; n = 5/25), and Homo sapiens (8.00%; n = 2/25). Lutzomyia evansi registered the highest feeding frequency (68.00%; n = 17/25), predominantly on a single (44.00%; n = 11/25) or multiple species (24.00%; n = 6/25). Conclusion. Results indicate a eclectic feeding behavior in Lu. evansi, implying potential reservoir hosts for Leishmania spp. and increasing transmission risk. This study is a first step towards understanding the diversity of mammalian blood sources used by sandflies, that may be crucial for vector identification and formulation of effective control measures.

Validation of Oxford nanopore sequencing for improved New World Leishmania species identification via analysis of 70-kDA heat shock protein

BACKGROUND

Leishmaniasis is a parasitic disease caused by obligate intracellular protozoa of the genus Leishmania. This infection is characterized by a wide range of clinical manifestations, with symptoms greatly dependent on the causal parasitic species. Here we present the design and application of a new 70-kDa heat shock protein gene (hsp70)-based marker of 771 bp (HSP70-Long). We evaluated its sensitivity, specificity and diagnostic performance employing an amplicon-based MinION™ DNA sequencing assay to identify different Leishmania species in clinical samples from humans and reservoirs with cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL). We also conducted a comparative analysis between our novel marker and a previously published HSP70 marker known as HSP70-Short, which spans 330 bp.

METHODS

A dataset of 27 samples from Colombia, Venezuela and the USA was assembled, of which 26 samples were collected from humans, dogs and cats affected by CL and one sample was collected from a dog with VL in the USA (but originally from Greece). DNA was extracted from each sample and underwent conventional PCR amplification utilizing two distinct HSP70 markers: HSP70-Short and HSP70-Long. The subsequent products were then sequenced using the MinION™ sequencing platform.

RESULTS

The results highlight the distinct characteristics of the newly devised HSP70-Long primer, showcasing the notable specificity of this primer, although its sensitivity is lower than that of the HSP70-Short marker. Notably, both markers demonstrated strong discriminatory capabilities, not only in distinguishing between different species within the Leishmania genus but also in identifying instances of coinfection.

CONCLUSIONS

This study underscores the outstanding specificity and effectiveness of HSP70-based MinION™ sequencing, in successfully discriminating between diverse Leishmania species and identifying coinfection events within samples sourced from leishmaniasis cases.

Cutaneous Leishmaniasis Emergence in Southeastern Mexico: The Case of the State of Yucatan

Environmental changes triggered by deforestation, urban expansion and climate change are present-day drivers of the emergence and reemergence of leishmaniasis. This review describes the current epidemiological scenario and the feasible influence of environmental changes on disease occurrence in the state of Yucatan, Mexico. Relevant literature was accessed through different databases, including PubMed, Scopus, Google, and Mexican official morbidity databases. Recent LCL autochthonous cases, potential vector sandflies and mammal hosts/reservoirs also have been reported in several localities of Yucatan without previous historical records of the disease. The impact of deforestation, urban expansion and projections on climate change have been documented. The current evidence of the relationships between the components of the transmission cycle, the disease occurrence, and the environmental changes on the leishmaniasis emergence in the state shows the need for strength and an update to the intervention and control strategies through a One Health perspective.

An overview of the trypanosomatid (Kinetoplastida: Trypanosomatidae) parasites infecting several mammal species in Colombia

BACKGROUND

Trypanosomatids are among the most critical parasites for public health due to their impact on human, animal, and plant health. Diseases associated with these pathogens manifest mainly in poor and vulnerable populations, where social, environmental, and biological factors modulate the case incidence and geographical distribution.

METHODS

We used Sanger and amplicon-based next-generation sequencing (NGS) in samples from different mammals to identify trypanosomatid infections in several departments in Colombia. A total of 174 DNA samples (18 humans, 83 dogs, and 73 wild mammals) were analyzed by conventional PCR using a fragment of the heat shock protein 70 (Hsp70) gene and Sanger sequenced the positive samples. Twenty-seven samples were sent for amplicon-based NGS using the same gene fragment. Data obtained were used to perform diversity analyses.

RESULTS

One hundred and thirteen samples were positive for PCR by Hsp70 fragment; these corresponded to 22.1% Leishmania spp., 18.6% L. amazonensis, 9.7% L. braziliensis, 14.2% L. infantum, 8% L. panamensis, and 27.4% Trypanosoma cruzi. Comparison of the identified species by the two sequencing technologies used resulted in 97% concordance. Alpha and beta diversity indices were significant, mainly for dogs; there was an interesting index of coinfection events in the analyzed samples: different Leishmania species and the simultaneous presence of T. cruzi and even T. rangeli in one of the samples analyzed. Moreover, a low presence of L. braziliensis was observed in samples from wild mammals. Interestingly, to our knowledge, this is the first report of Leishmania detection in Hydrochaeris hydrochaeris (capybara) in Colombia.

CONCLUSIONS

The Hsp70 fragment used in this study is an optimal molecular marker for trypanosomatid identification in many hosts and allows the identification of different species in the same sample when amplicon-based sequencing is used. However, the use of this fragment for molecular diagnosis through conventional PCR should be carefully interpreted because of this same capacity to identify several parasites. This point is of pivotal importance in highly endemic countries across South America because of the co-circulation of different genera from the Trypanosomatidae family. The findings show an interesting starting point for One Health approaches in which coevolution and vector-host interactions can be studied.

Surveillance and genotype characterization of zoonotic trypanosomatidae in Didelphis marsupialis in two endemic sites of rural Panama

Didelphis marsupialis has been reported as a competent reservoir for trypanosomatid parasites infections. The aim of this study was to measure Trypanosoma cruzi, T. rangeli, and Leishmania spp. infection rates and to characterize discrete typing units (DTUs) of T. cruzi in D. marsupialis from two Chagas disease endemic sites in Panama. Blood from 57 wild-caught D. marsupialis were examined from two rural communities, Las Pavas (N = 18) and Trinidad de las Minas (N = 39). Twenty-two (38.60%) opossums were positive for flagellates by general hemoculture. T. cruzi infection was confirmed by positive hemoculture and/or kDNA based PCR performed in 31/57 (54.39%) blood samples from opossums. T. rangeli infection was confirmed by hemoculture and/or TrF/R2-Primer PCR assay applied on 12/57 (21.05%) blood samples. Nine (15.79%) D. marsupialis harbored T. cruzi/T. rangeli coinfections. All opossums tested negative for Leishmania spp. by PCR assays based on kDNA and HSP70 gene amplification. There was a significant association between T. cruzi infection and site (Fisher exact test, p = 0.02), with a higher proportion of T. cruzi infected opossums in Las Pavas (77.78%, n = 14/18) compared to Trinidad de las Minas (43.59%, n = 17/39). A significant association was found between habitat type and T. cruzi infection in opossums across both communities, (X² = 6.91, p = 0.01, df = 1), with a higher proportion of T. cruzi infection in opossums captured in forest remnants (76%, 19/25) compared to peridomestic areas (37.5%, 12/32). T. rangeli detection, but not T. cruzi detection, may be improved by culture followed by PCR. TcI was the only DTU detected in 22 T. cruzi samples using conventional and real-time PCR. Eight T. rangeli positive samples were characterized as KP1(-)/lineage C. Trypanosome infection data from this common synanthropic mammal provides important information for improved surveillance and management of Chagas disease in endemic regions of Panama.

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Trypanosoma cruzi infection is common in Didelphis marsupialis from the studied sites.

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T. rangeli infection was confirmed in many opossums.

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All opossums tested negative for Leishmania infection.

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A higher proportion of T. cruzi infected opossums came from forest remnants.

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T. cruzi parasites were characterized as TcI and T. rangeli as KP1(-)/lineage C.

FLEBOTOMINOFAUNA Y PRIMER REGISTRO DE Lutzomyia aclydifera (DIPTERA: PSYCHODIDAE) EN EL CARIBE COLOMBIANO

Uno de los focos de leishmaniasis más importante de Colombia está en Los Montes de María, Departamento de Bolívar, específicamente en El Carmen de Bolívar. A la fecha están registradas 19 especies del género Lutzomyia, en este departamento, algunas con antecedentes como vectores de Leishmania spp. La presente nota informa la abundancia y la diversidad de la flebotominofauna en la zona rural de El Carmen de Bolívar. Mediante el uso de trampas de CDC, se colectaron 1327 hembras del género Lutzomyia entre enero a noviembre de 2018: Lu. evansi (81 %), Lu. panamensis (15,5 %), Lu. gomezi (2,9 %), Lu. dubitans (0,15 %), Lu. aclydifera (0,07 %), Lu. c. cayennensis (0,07 %), Lu. rangeliana (0,07 %) y Lu. serrana (0,07 %). La mayor abundancia de flebotomíneos se presentó en noviembre y la menor en abril, coincidiendo con los meses de lluvia y sequía, respectivamente; mientras que en enero se presentó la mayor diversidad. En esta investigación sobresalen Lu. evansi, Lu. panamensis y Lu. gomezi por sus antecedentes como vectores de Leishmania en el Departamento de Bolívar y otras regiones del país. Se reporta por primera vez para el Caribe Colombiano la especie Lu. aclydifera, la cual deberá ser vigilada en cuanto a su capacidad vectorial para Leishmania.

Revisiting the heterogeneous global genomic population structure of Leishmania infantum

Leishmania infantum is the main causative agent responsible for visceral leishmaniasis (VL), a disease with global distribution. The genomic structure and genetic variation of this species have been widely studied in different parts of the world. However, in some countries, this information is still yet unknown, as is the genomic behaviour of the main antigens used in VL diagnosis (rK39 and rK28), which have demonstrated variable sensitivity and specificity in a manner dependent on the geographic region analysed. The objective of this study was to explore the genomic architecture and diversity of four Colombian L. infantum isolates obtained in this study and to compare these results with the genetic analysis of 183 L. infantum isolates from across the world (obtained from public databases), as well as to analyse the whole rK39 and rK28 antigen sequences in our dataset. The results showed that, at the global level, L. infantum has high genetic homogeneity and extensive aneuploidy. Furthermore, we demonstrated that there are distinct populations of L. infantum circulating in various countries throughout the globe and that populations of distant countries have close genomic relationships. Additionally, this study demonstrated the high genetic variability of the rK28 antigen worldwide. In conclusion, our study allowed us to (i) expand our knowledge of the genomic structure of global L. infantum; (ii) describe the intra-specific genomic variability of this species; and (iii) understand the genomic characteristics of the main antigens used in the diagnosis of VL. Additionally, this is the first study to report whole-genome sequences of Colombian L. infantum isolates.

MAMÍFEROS URBANOS COLOMBIANOS: UNA REVISIÓN DE LO QUE SABEMOS Y LO QUE NOS FALTA

Los ecosistemas urbanos están entre los ambientes que más rápido crecen en el planeta debido al incremento de la población humana, y es necesaria información que permita tomar decisiones para el manejo y conservación de su biodiversidad. Por ello se revisaron las publicaciones sobre mamíferos urbanos colombianos y se analizaron cuatro aspectos: 1) la relación entre el número de publicaciones y el año, 2) la representación del conocimiento por regiones naturales y departamentos, 3) la relación entre el número de publicaciones y la población humana por departamento, y 4) la representación de los temas y órdenes de mamíferos estudiados en las diferentes regiones naturales. El número de publicaciones sobre los mamíferos urbanos se ha incrementado exponencialmente con el tiempo, pero estas no están distribuidas uniformemente entre las regiones naturales y departamentos. El número de publicaciones se incrementó con la población humana en los departamentos. Sin embargo, en algunos departamentos existe un número de publicaciones mayor al esperado, mientras que en otros están por debajo de las expectativas. Hay limitada información sobre las respuestas ecológicas de los mamíferos a la urbanización, su posibilidad de transmitir enfermedades, la composición de especies en la mayoría de las áreas urbanas y el efecto de la urbanización sobre la diversidad. Se sugiere aprovechar espacios como los campus universitarios e indicadores comportamentales de bajo costo para hacer experimentación y ayudar a desarrollar estrategias que permitan la coexistencia de humanos y mamíferos silvestres en y alrededor de las ciudades.

Primera aproximación a la fauna flebotomínea (Psychodidae: Phlebotominae) del departamento de Atlántico

Dentro del género Lutzomyiaalgunas especies son vectores de la enfermedad llamada leishmaniasis, la cual tiene implicaciones en la salud pública, desarrollando diferentes manifestaciones clínicas como leishmaniasis cutánea, visceral y mucocutánea que afectan altamente al ser humano. El objetivo de este estudio fuerealizar un inventario de las especies del género Lutzomyia presentes en seis zonas del departamento del Atlántico. Se implementaron 3 técnicas de capturas tradicionales: trampas CDC entre 18:00-06:00, trampa Shannon entre 19:00-22:00 y búsqueda activa de flebotomíneos con aspiradores bucales en troncos, bases de árboles y otros sitios entre 09:00-11:00 y 16:00-17:30, en seis municipios del departamento del Atlántico, Colombia. Se capturaron diez especies flebotomíneas y se reporta por vez primera para el departamento del Atlántico el hallazgo de Lutzomyia longipalpis y Lutzomyia atroclavata. De las diez especies capturadas, Lutzomyia longipalpistiene antecedentes como vector de Leishmania infantumen Colombia y en otras regiones de Latinoamérica, además es considerada el principal vector de leishmaniasis visceral en las Américas. La especie más abundante y con mayor distribución espacial fue Lu. evansi, principal vector de leishmaniasis visceral en la región Caribe. En conclusión,la riqueza de la fauna flebotomínea del departamento de Atlántico se actualiza a doce especies, con el primer registro de Lu. longipalpisy Lu. atroclavata. También se reporta la fauna flebotomínea por primera vez en localidades del departamento de Atlántico como Campeche, Puerto Colombia, Luruaco, Ponedera y Campo de la Cruz.