Ticks (Acari: Ixodidae) and rickettsiae associated with wild boars in a rural area of Minas Gerais, Brazil.

Wild boars or feral pigs are classified by the Brazilian Institute for the Environment and Renewable Resources (IBAMA) in "Category I of invasive exotic species". They cause economic losses, harm the environment, serve as hosts and reservoirs for several zoonotic disease agents, and provide a blood meal for tick species that act as vectors for zoonotic diseases. The objective of this study was to identify tick species on wild boars, assess host-seeking ticks in the related environment, and identify other potential tick hosts coexisting with wild boars on a farm located in the state of Minas Gerais, southeastern Brazil. Additionally, the study aimed to determine the presence of rickettsiae in these arthropods and assess the exposure of wild boars to rickettsiae species from the Spotted Fever Group and Rickettsia bellii through serology. A total of 3585 host-seeking ticks from three species (Amblyomma sculptum - 41.58%; Amblyomma dubitatum - 0.39% and Rhipicephalus microplus - 0.05%) were collected in the environment and A. sculptum was the most abundant species. Thirty-one wild boars were evaluated, resulting in the collection of 415 ticks, all of which were A. sculptum. Rickettsia DNA was not detected in samples of A. sculptum and R. microplus from the environment or in A. sculptum ticks from wild boars. However, all A. dubitatum ticks (n = 14) had Rickettsia bellii DNA confirmed by the species-specific PCR protocol. Out of the 31 serum samples from wild boars, 24 reacted with at least one Rickettsia antigen. Among these, seven individuals exhibited a reaction to a probable homologous antigen (PHA) of three rickettsiae species: R. rickettsii (n = 3), R. amblyommatis (n = 3) and R. rhipicephali (n = 1). Despite the high prevalence of seroreactivity, titers were low, indicating limited exposure to Rickettsia spp. Camera traps generated 874 animal records, capturing a total of 1688 individuals. At least 11 species of birds and 14 species of mammals (12 wild and two domestic) shared the environment with wild boars and potentially shared ticks with them. These findings provide baseline information for understanding the sharing of ticks and tick-borne pathogens between wild boars and other animals within the Cerrado biome. Further studies are necessary to monitor the potential and actual risk of wild boars to harbor infected ticks and their role in the transmission and maintenance cycle of Rickettsia spp.

Anti-neoplastic activity of Amblyomma sculptum, Amblyomma parvum and Rhipicephalus sanguineus tick saliva on breast tumor cell lines.

Cancer is one of the most troubling diseases and is becoming increasingly common. Breast cancer has a high cure rate when diagnosed early, but when diagnosed late, treatment is frequently painful, devastating and unsuccessful. The search for new treatments that are more effective and less harmful has led to several substances and biomolecules from plants and animals with potential anti-tumor activity. Within this context, ticks have emerged as an excellent source of new molecules with a wide array of therapeutic properties. Various molecules in tick saliva have immunomodulatory, anticoagulant, anti-inflammatory and anti-tumor effects across different tumor cell lines. Our study evaluates the effect of saliva from three widespread and important tick species in Brazil (Amblyomma sculptum, Amblyomma parvum and Rhipicephalus sanguineus) on MCF-7, MDA-MB-231 breast cancer cell lines and on the non-neoplastic MCF-10A cell line. We found that tick saliva from all three tick species showed cytotoxicity to tumor cells (MCF-7, MDA-MB-231) but not to the non-tumor cells (MCF-10A). Morphological changes on the surface of MCF-7 and MDA-MB-231 tumor cells did not occur on the MCF-10A cells. We also demonstrated that tumor cells die by apoptosis induced by caspase-3 and caspase 7 activity, suggesting that intrinsic pathway apoptosis may be triggered by tick saliva. These changes were not observed in MCF10A cells, which remained broadly unchanged even after exposure to diverse types of saliva. These results suggest that tick saliva from these tick species is a source of molecules, or biomolecules, useful for the potential source for the development of new breast cancer drugs.

Exploring the anti-tumoral effects of tick saliva and derived components.

Ticks are blood-feeding arthropods with an outstanding ability to remain attached to its host for considerable periods while blood-feeding and remaining unnoticed. Their success results from the ability to modulate hemostatic and host immune responses. The ability to "bypass" a host's defenses, prevent blood clotting and wound healing makes ticks utterly interesting animals for the development of new drugs. Studies worldwide on various tick species have shown that tick saliva possesses a wide array of lipidic and proteic biomolecules with useful properties. These include not only immunomodulatory, anti-inflammatory, anti-platelet and anti-clotting properties, but also cytotoxic and cytolitic properties that act against various cell types, and anti-angiogenic properties, which have gained increasing prominence. We searched PubMed, Science Direct, Elsevier and other sites for publications regarding tick saliva and its effects on cancer cells and angiogenesis. Our aim was to compile a list of molecules with potential for host adaptation and for the development of new cancer treatment drugs.