Publications by authors named "Roger I Rodriguez-Vivas"

Otobius megnini (spinose ear tick) is a cosmopolitan soft tick that parasitizes domestic and wild mammals, as well as humans. The larval and nymphal stages are common parasites that feed on blood inside the canal ears of hosts, while adults are nonfeeding and live off the host. Different nymphal stages of O.

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Amblyomma cf. parvum (Ixodida: Ixodidae) is an ectoparasite of domestic animals and wildlife on the American continent. There is little information on the efficacy of acaricides for the control of this tick species in domestic animals.

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The monthly fluctuation of adult Ixodes keiransi in dogs from two cattle farms in southeastern Mexico was determined. In ranch 1 (R1), 6-7 mixed breed dogs from six months to five years of age; while in ranch 2 (R2), 7-8 mixed breed dogs from one to four years of age, were followed. All dogs were monthly inspected for tick infestation through one year.

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  • Ticks, particularly from the Ixodes genus, are blood-feeding ectoparasites with at least 245 species, and the Ixodes affinis has a broad distribution from South America to the U.S.
  • This study aims to explore the genetic diversity of I. affinis across the Americas, especially in areas where data is sparse, and to clarify its taxonomy, suggesting it may represent a complex of four distinct species.
  • The research involved collecting samples from South Carolina and Yucatán, resulting in significant genetic structure findings that support the idea that I. affinis consists of several closely related species.
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  • - The study investigates the presence of Leptospira bacteria in small mammals (bats and rodents) captured in Yucatan, Mexico, and examines how the environment at capture sites affects this occurrence.
  • - A total of 82 bats and 78 rodents were studied, revealing a combined Leptospira infection rate of 21.2%, with slightly higher rates in bats (21.9%) compared to rodents (20.5%).
  • - The research identified the main Leptospira species as L. borgpetersenii and L. noguchii, and found that sites with tropical deciduous forests had more infected rodents, while those with tropical sub-deciduous forests had greater diversity in infected bats.*
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  • The oyster mushroom, known for its culinary use, may also possess medicinal properties and has been studied for its potential as a natural acaricide against ticks, which are significant livestock parasites.
  • The study demonstrated that a fungal extract showed high effectiveness in killing tick larvae, achieving 89% mortality compared to 91% from a standard control, and also reduced egg-laying in female ticks.
  • Molecular docking analysis suggested that compounds in the fungal extract, such as rutin, naringin, and myricetin, interact strongly with a specific target protein, indicating the extract's potential as an alternative to traditional tick control methods in livestock.
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Trypanosoma cruzi, the causal agent of American trypanosomiasis, and Leishmania spp., the causal agents of Leishmaniasis, are prevalent in more than 20 American countries, including Mexico. Dogs have been reported as incidental hosts for both parasites and may be helpful as transmission sentinels.

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Gastrointestinal nematodes (GIN) are a major impediment to breeding and exploitation of horses. Traditional control of GIN has generated resistance to main anthelmintics, including ivermectin. An analysis of five ranches with a history of IVM use was done to determine the efficacy and resistance of GIN to IVM treatment in horses from the Mexican southeast.

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Rickettsia parkeri belongs to the spotted fever group (SFG) of the Rickettsia genus. This bacterium causes mild rickettsiosis in humans and is mainly transmitted by Amblyomma ticks. Its medical importance is emerging in the Americas, including Mexico.

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The lethal and repellent effect of the synthetic insecticide amitraz and the botanical insecticides eugenol and thymol separately and together in binary mixtures was tested against late-stage nymphs of a susceptible strain of Triatoma infestans, the main vector of Trypanosoma cruzi, the etiological agent of Chagas disease, in the Southern Cone of America. For the lethality study, the LD was determined for each insecticide alone and in binary mixture by topical application. The combination index (CI) was established to quantify interactions occurring between the insecticides.

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  • Cutaneous leishmaniasis (CL) is a zoonotic infection studied in Khyber Pakhtunkhwa, Pakistan, focusing on the risk of epidemics among 3188 patients analyzed in 2021.
  • The research found that young males are predominantly affected, with most lesions on the face, and CL episodes peak in the southern region during winter.
  • Using advanced mapping techniques, hotspots for CL transmission were identified, particularly in areas like Bannu, and environmental factors such as increased precipitation and temperature were linked to higher infection rates.
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  • The study investigates the acaricidal effects of an ethanolic plant extract on a major bovine ectoparasite, comparing it with the commonly used chemical trichlorfon through adult immersion and larval packet tests.
  • The plant extract demonstrated significant inhibitory effects on tick oviposition and larval mortality rates, especially at higher concentrations (40 mg/mL), indicating its potential as an effective alternative in tick management.
  • Molecular docking and simulations revealed strong interactions between specific phytochemicals in the extract and the target protein Glutathione S-transferases, suggesting a computational foundation for developing new acaricidal agents.
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  • A case study details the clinical symptoms and findings of Lagochilascaris minor, a parasitic worm, in a domestic cat from Veracruz, Mexico.
  • The cat exhibited a neck fistula containing 32 nematodes, which were identified as Lagochilascaris spp. based on physical characteristics.
  • DNA analysis confirmed the species as L. minor, showing a 100% match with samples from Costa Rica, marking the first report of this parasite in domestic cats in Veracruz and highlighting its presence as a zoonotic threat in the region.
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  • * Results revealed 23.9% of dogs tested positive for TG DNA, with factors like mixed-breed status and antiparasitic treatment linked to lower infection risks.
  • * The study highlighted that adult dogs with limited outdoor activity had reduced infection risks compared to puppies, and emphasized the need for further prevention strategies to control TG transmission and protect against potential zoonotic risks.
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This study evaluates the acaricidal activity of Mexican native plants against a Rhipicephalus microplus population resistant to both amitraz and cypermethrin. To explore the activities of plants, the larvicidal effects of 72 Kupchan fractions (Hex, DCM, AcOEt and MeOH:HO) of 18 plant species collected in Veracruz, Mexico were studied. The evaluation of the Kupchan fractions against double resistant R.

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Human tick-borne rickettsioses are caused by Rickettsia africae, Rickettsia massiliae, Rickettsia parkeri, Rickettsia philipi and Rickettsia rickettsii in the American continent. Rickettsia parkeri represents the second most important agent of eschar-associated spotted fever throughout the American continent. In Mexico, the presence of three strains of this bacterium (Black Gap, Maculatum and Atlantic Rainforest) has recently been reported in four species of ticks from five states (Baja California, Campeche, Sonora, Tabasco and Veracruz) and rickettsaemia was demonstrated in a dog from the state of Yucatán.

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Introduction: Endoparasites and ectoparasites in dogs are of global distribution. The close relationship between dogs and man implies a risk for the transmission of zoonotic parasites. Therefore, it is necessary to determine the parasites hosted by dogs in specific areas and the factors associated with their presence.

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The prevalence, resistance ratios and factor associated with Rhipicephalu microplus populations resistant to amitraz, flumethrin, coumaphos, and ivermectina (IVM) in Mexico were studied. Field tick populations were collected from 54 farms in 15 different states of Mexico. The dose-response bioassays were carried out using the larval immersion test (amitraz and IVM) and the modified larval packet test (flumethrin and coumaphos) against R.

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Intensive use of macrocyclic lactones for parasite control exerts strong selective pressure for arthropods such as ticks to become resistant to them. Rhipicephalus sanguineus sensu stricto is a tick and disease vector of significant public health and veterinary importance worldwide. We assessed the toxicological response to the macrocyclic lactone ivermectin (IVM) in R.

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Article Synopsis
  • - The study investigated the prevalence of gastrointestinal nematodes resistant to common dewormers (albendazole sulfoxide, ivermectin, and levamisole) in hair-sheep farms across Campeche and Yucatán, Mexico, from 2016 to 2019, using the faecal egg count reduction test (FECRT).
  • - The farms surveyed had more than 100 grazing ewes, and resistance was measured using three different formulae that estimated the percentage reduction in parasite eggs post-treatment.
  • - Results indicated high resistance rates to ivermectin (up to 100% in some areas), consistent findings for albendazole sulfoxide, while levamisole resistance showed some variability depending on the
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The genus Rickettsia encompasses 35 valid species of intracellular, coccobacilli bacteria that can infect several eukaryotic taxa, causing multiple emerging and re-emerging diseases worldwide. This work aimed to gather and summarise the current knowledge about the genus Rickettsia in Mexico, updating the taxonomy of the bacteria and their hosts by including all the records available until 2020, to elucidate host-parasite relationships and determine the geographical distribution of each Rickettsia species present in the country. Until now, 14 species of Rickettsia belonging to four groups have been recorded in Mexico.

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The present study aimed to evaluate the anthelmintic activity of leaf and bark extracts of collected during different seasons and their major constituents on eggs of , and cyathostomins. Specifically, the eclosion inhibition of the methanolic extracts of the leaves and bark of collected during the dry and rainy seasons (600-37.5 μg/ml) were evaluated in addition to the fractions, sub-fractions (300-37.

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