Capybaras (Hydrochoerus hydrochaeris) are affected by a wide range of protozoan and metazoan-derived parasitic diseases. Among parasites of free-ranging capybaras are soil-, water-, food- and gastropod-borne parasitosis, today considered as opportunistic infections in semiaquatic ecosystems. The overlapping of the capybara’s natural ecological habitats with human and domestic animal activities has unfortunately increased in recent decades, thereby enhancing possible cross- or spillover events of zoonotic parasites. Due to this, three synanthropic wild capybara populations in the Orinoco Basin were studied for the occurrence of gastrointestinal parasite infections. A total of forty-six fecal samples were collected from free-ranging capybaras in close proximity to livestock farms. Macroscopical analyses, standard copromicroscopical techniques, coproELISA, PCR, and phylogenetic analysis revealed thirteen parasite taxa. In detail, the study indicates stages of five protozoans, four nematodes, one cestode, and three trematodes. Two zoonotic parasites were identified (i.e., Plagorchis muris, and Neobalantidium coli). The trematode P. muris represents the first report within South America. In addition, this report expands the geographical distribution range of echinocoelosis (Echinocoleus hydrochoeri). Overall, parasitological findings include two new host records (i.e., P. muris, and Entamoeba). The present findings collectively constitute baseline data for future monitoring of wildlife-derived anthropozoonotic parasites and call for future research on the health and the ecological impact of this largest semiaquatic rodent closely linked to humans, domestic and wild animals.

Background: Rickettsiae are obligate intracellular Gram-negative bacteria that are the causative agent of rickettsioses and are spread to vertebrate hosts by arthropods. There are no previous reports of isolation of Rickettsia amblyommatis for Colombia. Methods: A convenience sampling was executed in three departments in Colombia for direct collection of adult ticks on domestic animals or over vegetation. Ticks were screened for the presence of Rickettsia spp. by real-time polymerase chain reaction (qPCR) amplifying the citrate synthase gene (gltA), and the positive sample was processed for isolation and further molecular characterization by conventional PCR. The absolute and relative frequencies were calculated for several tick species variables. All products from conventional PCR were further purified and sequenced by the Sanger technique. Representative sequences of 18 Rickettsia species were downloaded from GenBank. Consensus phylogenetic trees were constructed for the gltA, ompB, ompA, and htrA genes with 1000 replicates, calculating bootstrap values through the maximum likelihood method and the generalized time reversible substitution model in the MEGA 7.0 software program. Results: One female Amblyomma mixtum collected on vegetation was amplified by qPCR (gltA), indicating a frequency of 1.6% (1/61) for Rickettsia spp. infection. Sequence analysis of a rickettsial isolate from this tick in BLASTn showed 100% identity with gltA (340 base pairs [bp]), 99.87% for ompB (782 bp), 98.99% for htrA (497 bp), and 100% for ompA (488 bp) to R. amblyommatis. Concatenated phylogenetic analysis confirmed these findings indicating that the isolate is grouped with other sequences of Amblyomma cajennense complex from Panama and Brazil within the R. amblyommatis clade. Conclusions: This paper describes the isolation and early molecular identification of a R. amblyommatis strain from A. mixtum in Colombia. Graphical

Studies evaluating candidate tick-derived proteins as anti-tick vaccines in natural hosts have been limited due to high costs. To overcome this problem, animal models are used in immunization tests. The aim of this article was to review the use of rabbits as an experimental model for the evaluation of tick-derived proteins as vaccines. A total of 57 tick proteins were tested for their immunogenic potential using rabbits as models for vaccination. The most commonly used rabbit breeds were New Zealand (73.8%), Japanese white (19%), Californians (4.8%) and Flemish lop-eared (2.4%) rabbits. Anti-tick vaccines efficacy resulted in up to 99.9%. Haemaphysalis longicornis (17.9%) and Ornithodoros moubata (12.8%) were the most common tick models in vaccination trials. Experiments with rabbits have revealed that some proteins (CoAQP, OeAQP, OeAQP1, Bm86, GST-Hl, 64TRP, serpins and voraxin) can induce immune responses against various tick species. In addition, in some cases it was possible to determine that the vaccine efficacy in rabbits was similar to that of experiments performed on natural hosts (e.g., Bm86, IrFER2, RmFER2, serpins and serine protease inhibitor). In conclusion, results showed that prior to performing anti-tick vaccination trials using natural hosts, rabbits can be used as suitable experimental models for these studies.

The advancement of multi-omics technologies is crucial to deepen knowledge on tick biology. These approaches, used to study diverse phenomena, are applied to experiments that aim to understand changes in gene transcription, protein function, cellular processes, and prediction of systems at global biological levels. This review addressed the application of omics data to investigate and elucidate tick physiological processes, such as feeding, digestion, reproduction, neuronal, endocrine systems, understanding population dynamics, transmitted pathogens, control, and identifying new vaccine targets. Furthermore, new therapeutic perspectives using tick bioactive molecules, such as anti-inflammatory, analgesic, and antitumor, were summarized. Taken together, the application of omics technologies can help to understand the protein functions and biological behavior of ticks, as well as the identification of potential new antigens influencing the development of alternative control strategies and, consequently, the tick-borne disease prevention in veterinary and public health contexts. Finally, tick population dynamics have been determined through a combination of environmental factors, host availability, and genetic adaptations, and recent advances in omics technologies have improved our understanding of their ecological resilience and resistance mechanisms. Future directions point to the integration of spatial omics and artificial intelligence to further unravel tick biology and improve control strategies.

Existem poucos registros de animais selvagens servindo como hospedeiros de carrapatos na região de savana inundada da Orinoquia, na Colômbia; portanto, o objetivo deste estudo foi identificar e mapear os carrapatos que infestam esses animais. Foram amostrados dez locais do município de Arauca, departamento de Arauca, onde foram coletados carrapatos que infestavam 19 animais selvagens, classificados em 14 espécies, fornecendo novas informações sobre infestação por carrapatos nos táxons (i) aves: Crax daubentoni, (ii) mamíferos: Dasypus sabanicola, Dicotyles tajacu, Hydrochoerus hydrochaeris, Leopardus tigrinus, Myrmecophaga tridactyla, Odocoileus virginianus, Procyon cancrivorus, Urocyon cinereoargenteus e Tamandua tetradactyla e (iii) répteis: Boa constrictor, Chelonoidis denticulata, Eunectes murinus e Iguana iguana. Foram identificados 85 carrapatos, classificados nas espécies Amblyomma mixtum, com 72,8%, seguido por Amblyomma dissimile, com 11,7%, Rhipicephalus microplus, com 8,2%, Dermacentor nitens, com 4,7% e Amblyomma nodosum, com 2,3%. Nos carrapatos, a espécie Amblyomma mixtum foi aquele em que ocorreu maior variedade de infestações aos hospedeiros, parasitando 53,8%. Hydrochoerus hydrochaeris foi o que apresentou maior variedade de espécies de carrapatos, sendo infestado por Amblyomma mixtum e Dermacentor nitens. A diversidade e a ampla distribuição destes animais selvagens tornam-nos potenciais hospedeiros de carraças de importância médica e veterinária, tendo em conta a estreita interação ambiental, cultural e econômica que se desenvolveu entre animais selvagens, domésticos, carraças, agentes patogênicos e humanos.

Rhipicephalus microplus is a widespread tick species causing significant economic losses and transmitting pathogens to cattle. The R. microplus populations utilized in tick research are frequently maintained under laboratory conditions for many years. Despite this, morphological abnormalities developed in laboratory‐maintained strains remain underexplored. Here, we analyzed the Porto Alegre (POA) strain, maintained under controlled conditions for nearly four decades, assessing external and internal morphological abnormalities across generations and their impact on biological parameters. We identified a low frequency (~0.9%) of diverse external malformations, predominantly idiosomal asymmetries, accompanied by histological gut alterations indicative of cellular dysfunction. Malformed ticks exhibited significantly reduced body weight, oviposition, and fertility compared to normal individuals. These abnormalities were not heritable but persisted sporadically, suggesting multifactorial origins. Our findings indicate that morphological malformations impair feeding efficiency and reproductive capacity, potentially limiting the fitness of affected ticks. This study enhances understanding of morphological variation in R. microplus and its biological implications and will inform strain maintenance and tick biology research.