The saliva of hematophagous arthropods contains a group of active proteins to counteract host responses against injury and to facilitate the success of a bloodmeal. These salivary proteins have significant impacts on modulating pathogen transmission, immunogenicity expression, the establishment of infection, and even disease severity. Recent studies have shown that several salivary proteins are immunogenic and antibodies against them may block infection, thereby suggesting potential vaccine candidates. Here, we discuss the most relevant salivary proteins currently studied for their therapeutic potential as vaccine candidates or to control the transmission of human vector-borne pathogens and immune responses against different arthropod salivary proteins.

Ticks are obligatory hematophagous ectoparasites that transmit pathogens among various vertebrates, including humans. The microbial and viral communities of ticks, including pathogenic microorganisms, are known to be highly diverse. However, the factors driving this diversity are not well understood. The tropical horse tick, Dermacentor nitens, is distributed throughout the Americas and it is recognized as a natural vector of Babesia caballi and Theileria equi, the causal agents of equine piroplasmosis. In this study, we characterized the bacterial and viral communities associated with partially fed Dermacentor nitens females collected using a passive survey on horses from field sites representing three distinct geographical areas in the country of Colombia (Bolivar, Antioquia, and Cordoba). RNA-seq and sequencing of the V3 and V4 hypervariable regions of the 16S rRNA gene were performed using the Illumina-Miseq platform (Illumina, San Diego, CA, USA). A total of 356 operational taxonomic units (OTUs) were identified, in which the presumed endosymbiont, Francisellaceae/Francisella spp., was predominantly found. Nine contigs corresponding to six different viruses were identified in three viral families: Chuviridae, Rhabdoviridae, and Flaviviridae. Differences in the relative abundance of the microbial composition among the geographical regions were found to be independent of the presence of Francisella-like endosymbiont (FLE). The most prevalent bacteria found in each region were Corynebacterium in Bolivar, Staphylococcus in Antioquia, and Pseudomonas in Cordoba. Rickettsia-like endosymbionts, mainly recognized as the etiological agent of rickettsioses in Colombia, were detected in the Cordoba samples. Metatranscriptomics revealed 13 contigs containing FLE genes, suggesting a trend of regional differences. These findings suggest regional distinctions among the ticks and their bacterial compositions.

La babesiosis afecta principalmente a bovinos y humanos; en su transmisión están implicadas las garrapatas, particularmente Rhipicephalus microplus, especie distribuida ampliamente en Latinoamérica. El método diagnóstico utilizado para determinar la presencia de Babesia spp. en garrapatas es la microscopía de hemolinfa, diagnóstico menos sensible que la PCR, la cual tiene una sensibilidad entre 95%–100% y una especificidad del 100%. En Colombia, zonas como la Costa Atlántica, el Bajo Cauca y Urabá son ecológicamente aptas para la presencia del parásito y del vector, considerando que se han registrado garrapatas de los géneros Dermacentor, Amblyomma y Rhipicephalus, implicadas en la transmisión de diversos patógenos de interés médico y veterinario. El estudio de la dinámica de transmisión por garrapatas es esencial para la elaboración de estrategias de control adecuadas. El objetivo de este trabajo fue identificar las especies de garrapatas presentes en predios ganaderos de la región de Urabá (Colombia) y su frecuencia de infección por Babesia bovis y B. bigemina. Se muestrearon 202 bovinos, en 30 predios de 15 localidades de los municipios Turbo y Necoclí. Se recolectaron 515 garrapatas; la especie predominante fue R. microplus 98% (507/515); la presencia del género Amblyomma estuvo asociada a predios aledaños de zonas boscosas. La frecuencia de infección en 162 subconjuntos de garrapatas (154 de R. microplus y 8 especímenes de A. cajennense) fue 18,5% (30/162), 15,4% (25/162) por B. bigemina, 4,9% (8/162) por B. bovis y 1,8% (3/162) de coinfección por estas especies.

Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae), Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae), and Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) are 3 important stored product pests of maize, but there has been little work evaluating how they vector microbes. While there has been some work assessing the microbial ecology of S. zeamais, none has directly assessed whether they transfer microbes to new food patches. Thus, we evaluated the ability of both species to vector microbes when given the opportunity to forage on sterilized potato dextrose agar dishes after a 0, 24, or 72 h dispersal period in a sterilized container. We subsequently photographed the dishes at 3 and 5 d after introduction and quantified the microbial growth using ImageJ. In addition, we isolated unique morphotypes of fungi, extracted DNA and amplified the internal transcribed spacer 5/4 intergenic spacer region, then sequenced to determine fungal identity. We found that 3 species readily vectored several plant pathogenic microbes, including 21 taxa from more than 11 genera, notably Aspergillus spp. Increasing dispersal period (0, 24, 72 h) resulted in a third less microbial growth (mean microbial growth or mean greyscale value from 0 to 255) by S. zeamais after 72 h, while for P. truncatus it resulted in a 2.7-fold increase in microbial growth. Dispersal by S. zeamais (0, 24, 72 h) resulted in 6.6-fold more microbial growth than dispersal by P. truncatus. There was 1.5- to 3.7-fold more microbial growth after 5 d than 3 d by each species. This research has important implications for food safety in the postharvest environment, especially for maize production, storage, and processing.

Ticks are obligatory hematophagous ectoparasites that transmit pathogens among various vertebrates, including humans. The composition of the microbial and viral communities in addition to the pathogenic microorganisms is highly diverse in ticks, but the factors driving the diversity are not well understood. The tropical horse tick, Dermacentor nitens , is distributed throughout the Americas and it is recognized as a natural vector of Babesia caballi and Theileria equi , the causal agents of equine piroplasmosis. We characterized the bacterial and viral communities associated with partially-fed D. nitens females collected by a passive survey on horses from field sites representing three distinct geographical areas in Colombia (Bolivar, Antioquia, and Cordoba). RNA-seq and sequencing of the V3 and V4 hypervariable regions of the 16S rRNA gene were performed using the Illumina-Miseq platform. A total of 356 operational taxonomic units (OTUs) were identified, in which the presumed endosymbiotic Francisellaceae/ Francisella spp. was predominantly found. Nine contigs corresponding to six different viruses were identified in three viral families: Chuviridae, Rhabdoviridae, and Flaviviridae. Differences in the relative abundance of the microbial composition among the geographical regions were found to be independent of the presence of Francisella -Like Endosymbiont (FLE). The most prevalent bacteria found on each region were Corynebacterium in Bolivar, Staphylococcus in Antioquia, and Pseudomonas in Cordoba. Rickettsia -like endosymbionts, mainly recognized as the etiological agent of rickettsioses in Colombia were detected in the Cordoba samples. Metatranscriptomics revealed 13 contigs containing FLE genes, suggesting a trend of regional differences. These findings suggest regional distinctions among the ticks and their bacterial compositions.

Acute febrile syndrome is a frequent reason for medical consultations in tropical and subtropical countries where the cause could have an infectious origin. Malaria and dengue are the primary etiologies in Colombia. As such, constant epidemiological surveillance and new diagnostic tools are required to identify the causative agents. A descriptive cross-sectional study was conducted to evaluate the circulation and differential diagnosis of six pathogens in two regions of Colombia. The results obtained via multiplex reverse transcription polymerase chain reaction combined with a microwell hybridization assay (m-RT-PCR-ELISA) were comparable to those obtained using rapid tests conducted at the time of patient enrollment. Of 155 patients evaluated, 25 (16.1%) and 16 (10.3%) were positive for malaria and dengue, respectively; no samples were positive for any of the other infectious agents tested. In most cases, m-RT-PCR-ELISA confirmed the results previously obtained through rapid testing.