Towards an Effective, Rational and Sustainable Approach for the Control of Cattle Ticks in the Neotropics

Ticks and transmitted pathogens constitute a major burden for cattle industry in the Neotropics. To address this limitation, the Spanish Ibero-American Program of Science and Technology in Development office (CYTED) supported from 2018 a network of scientists named “LaGar” (CYTED code 118RT0542) aimed at optimizing the control strategies of cattle ticks in the neotropical region. As part of network activities, a meeting and course were organized on 4–8 November 2019 in Querétaro, Mexico to address the objective of developing the infrastructure necessary for an effective, sustainable (i.e., combination of efficacious acaricides with anti-tick vaccines) and rational (i.e., considering tick ecology, seasonal dynamics and cattle-wildlife interactions) control of cattle tick infestations and transmitted pathogens. The course was focused on scientists, students, cattle holders and producers and pharmaceutical/industry representatives. In this way the course addressed the different views presented by participants with the conclusion of producing a research-driven combination of different interventions for the control of tick tick-borne diseases.Fil: Estrada Peña, Agustín. No especifíca;Fil: Szabó, Matías. Universidade Federal de Minas Gerais; BrasilFil: Labruna, Marcelo. Universidade de Sao Paulo; BrasilFil: Mosqueda, Juan. Universidad Autonoma de Queretaro.; MéxicoFil: Merino, Octavio. Universidad de Tamaulipas; MéxicoFil: Tarragona, Evelina Luisa. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Venzal, José M.. Universidad de la Republica; UruguayFil: de la Fuente, José. Instituto de Investigación En Recursos Cinegéticos; Españ

Exploring the ecological and evolutionary relationships between Rickettsia and hard ticks in the Neotropical region

This study addresses a meta-analysis of the distribution of Rickettsia spp. in the Neotropical region, as well as their associations with ticks and vertebrates. A total of 219 published reports on Rickettsia in ticks in the target region were compiled, providing 599 records of 31 species of Rickettsia recorded in 50 species of Ixodidae. The aim is to capture the phylogenetic relationships between rickettsiae and the ticks carrying them in the target region, with a focus on the co-speciation ticks-rickettsiae. We compared the phylogeny of ticks, the records of rickettsiae, the environmental gradients colonized by ticks and the effect of the phylogenetic composition of vertebrates feeding ticks on the detection of Rickettsia in ticks. Results show that differences in rickettsial composition in ticks do not depend on the vertebrate's blood-source. This is the first time this result is demonstrated. This study pinpoints that some Neotropical rickettsial organisms are associated with well-defined phylogenetical clusters of ticks. Secondarily, and probably only in a few cases, rickettsiae share species of phylogenetically distant ticks distributed along a gradient of environmental traits in which the ticks overlap (i.e., the different strains of Rickettsia parkeri sensu lato). We outline the importance of some ticks that share hosts and habitat: these ticks may act as “bridges” for the circulation of rickettsial species. There are also many species of Rickettsia that have been detected so far in only one tick species, pointing to a tight relationship or to the lack of data preventing conclusions about the detection of these bacteria in other ticks. Two species, namely Rickettsia amblyommatis and Rickettsia bellii have been recorded in the majority of ticks in the region (mainly Amblyomma spp.) and seem to be not associated with definite tick species because they may be an essential symbiont of the ticks. We conclude that an adequate analysis of rickettsiae-ticks-habitat is necessary to address the human health issues derived from the infections by rickettsiae.EEA RafaelaFil: Estrada-Peña, Agustin. Universidad de Zaragoza. Facultad de Veterinaria. Departamento de Patología Animal; EspañaFil: Estrada-Peña, Agustin. Instituto Agroalimentario de Aragón. Group of Research on Emerging Zoonoses; EspañaFil: Binder, Lina C. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Medicina Veterinária Preventiva e Saúde Animal; BrasilFil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Nava, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Szabó, Matías P.J. Universidade Federal de Uberlandia. Faculdade de Medicina Veterinaria; BrasilFil: Labruna, Marcelo B. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Medicina Veterinária Preventiva e Saúde Animal; Brasi

Amblyomma parvum Aragão, 1908 (Acari: Ixodidae): Phylogeography and systematic considerations

The geographical distribution of Amblyomma parvum Aragão 1908 in the New World is disjunct, with two main clusters separated from each other by the Amazon basin. The main objectives of this study were to further investigate the systematic relationships within A. parvum, to determine whether or not populations from different geographical areas might represent cryptic species, and to reconstruct the phylogeographical evolutionary history of the species. The genetic diversity of A. parvum collected throughout its distributional range was analyzed by using 6 molecular markers: 5 mitochondrial [the small and the large ribosomal subunits 12rDNA and 16SrDNA, the cytochrome oxidase I (COI) and II (COII) and the control region or d-loop (DL)], and one nuclear (ITS2, Inter transcribed spacer 2). Phylogenetic trees were inferred by using maximum parsimony and Bayesian analyses. In addition, node dating was attempted for the main lineages identified phylogenetically. Although mitochondrial and nuclear topologies were not totally congruent, they all identified at least two main supported clusters, a Central American lineage, and a Brazilian-Argentinian lineage. Clade support and divergence values strongly suggest that the two lineages correspond to different taxonomic entities. Node dating placed the split between the Central American and the Brazilian-Argentinian lineages at approximately 5.8–4.9 Mya, just after the progressive replacement of the dry areas that occupied the northern part of South America by the Amazon Basin in the early-mid Miocene. This event might be the cause of fragmentation and putative speciation within the ancestral relatively xerophilic A. parvum population.EEA RafaelaFil: Lado, Paula. Georgia Southern University. Institute for Coastal Plain Science. United States National Tick Collection; Estados UnidosFil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Labruna, Marcelo B. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Medicina Veterinária Preventiva e Saúde Animal; BrasilFil: Szabó, Matías P.J. Universidade Federal de Uberlandia. Faculdade de Medicina Veterinaria e Zootecnia; BrasilFil: Durden, Lance A. Georgia Southern University. Biology Department; Estados UnidosFil: Bermudez, Sergio. Instituto Conmemorativo Gorgas de Estudios de la Salud. Departamento de Investigación en Entomología Médica; PanamáFil: Montagna, Matteo. Università degli Studi di Milano. Dipartamento di Scienze Agrarie e Ambientali; ItaliaFil: Sánchez Quirós, Ana C. Universidad de Costa Rica. Escuela de Biología; Costa RicaFil: Beati, Lorenza. Georgia Southern University. Institute for Coastal Plain Science. United States National Tick Collection; Estados Unido

Different lines of evidence used to delimit species in ticks: A study of the South American populations of Amblyomma parvum (Acari: Ixodidae)

The goal of this work was to combine different lines of evidence besides that of molecular markers to delimit species in ticks when the molecular data are not totally congruent. Two groups (Argentina, Brazil) of South American populations of Amblyomma parvum were compared to test whether the splitting of these two lineages suggested by genetic analyses is complete. Comparative studies of reproductive compatibility, morphological analyses of fixed characters, and comparison of population distributions in spatially defined ecological niches were performed.The morphological comparisons of both discrete and morphometric characters showed no differences among A. parvum ticks from Argentina and Brazil. The intercrosses and backcrosses showed evidence of pre- and post-zygotic compatibility between the two groups. No significant differences in environmental traits were found which would justify the separation of the records of A. parvum in distinct groups. Although the gene flow between the two groups of populations is limited, the absence of reproductive barriers, the lack of significant morphological differences, and the absence of significant differences in the niche preferences indicate that populations of A. parvum from Argentina and Brazil should be treated as a single species. The speciation conjectures suggested by some analyses of mitochondrial DNA sequences were not supported when different lines of evidences were compared.Fil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Gerardi, Monize. Universidade Federal de Uberlandia; BrasilFil: Szabó, Matías P. J.. Universidade Federal de Uberlandia; BrasilFil: Mastropaolo, Mariano. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Martins, Thiago F.. Universidade de Sao Paulo; BrasilFil: Labruna, Marcelo B.. Universidade de Sao Paulo; BrasilFil: Beati, Lorenza. Georgia Southern University; Estados UnidosFil: Estrada Peña, Agustín. Universidad de Zaragoza; EspañaFil: Guglielmone, Alberto Alejandro. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentin

The taxonomic status of Rhipicephalus sanguineus (Latreille, 1806)

The brown dog tick, Rhipicephalus sanguineus sensu stricto, is a species with considerable public health and economic importance. However, the taxonomic status of this species is far from resolved. After more than 110 years of scientific work on R. sanguineus s.s., the situation is that there is no type, no solid description, nor is there a consensus about the range of morphological variability within the species. Recent findings based on laboratory crosses and molecular genetics strongly suggest that there are several entities grouped under the same name. Here we review the history of the taxon, and we point out the caveats behind any further work on this tick. The current taxonomic status of R. sanguineus s.s. thus lacks an informative original description, and is based on the existence of several morphological descriptions based on ticks originating from different populations, which show, in some cases, biological incompatibility and significant genetic divergence. We suggests that as a result it is not possible to assign the specific name R. sanguineus s.s. to any population. Further work is required based on the rules issued by the International Code of Zoological Nomenclature to clearly define the morphological range of the different populations.EEA RafaelaFil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Estrada-Peña, Agustin. Universidad de Zaragoza. Facultad de Veterinaria. Departamento de Patología Animal; EspañaFil: Petney, Trevor. Karlsruhe Institute of Technology. Department of Ecology and Parasitology; AlemaniaFil: Beati, Lorenza. Georgia Southern University. Institute for Coastal Plain Science. United States National Tick Collection; Estados UnidosFil: Labruna, Marcelo B. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Medicina Veterinária Preventiva e Saúde Animal; BrasilFil: Szabó, Matías P.J. Universidade Federal de Uberlandia. Faculdade de Medicina Veterinaria; BrasilFil: Venzal, José Manuel. Universidad de la República. CENUR Litoral Norte-Salto. Facultad de Veterinaria. Departamento de Parasitología Veterinaria; UruguayFil: Mastropaolo, Mariano. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; ArgentinaFil: Mangold, Atilio Jose. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Guglielmone, Alberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Regional Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Ornithodoros cerradoensis n. sp. (Acari: Argasidae), a member of the Ornithodoros talaje (Guérin-Méneville, 1849) group, parasite of rodents in the Brazilian Savannah

Ornithodoros cerradoensis n. sp. is described from field-collected and laboratory reared nymphs, males, females, and larvae parasitizing the rodents Cavia aperea and Thrichomys sp. in the Brazilian Savannah. This new species is morphologically and genetically related with the Ornithodoros talaje group and can be separated from other Neotropical species using the following combination of characters: larva with 18 pairs of setae on dorsum (seven anterolateral, four central and seven posterolateral), hypostome with median dentition 2/2; adults provided with large mammillae; dorsal disks surrounded by bulked marginal ridges delimiting barely pebbled areas; three disks in the anterolateral file, and median disk not merging with the posteromedian file. Feeding assays in the laboratory demonstrated that (1) larvae of O. cerradoensis are slow-feeders (∼6 days), (2) first nymphal instar (N1) molts to second instar (N2) without feeding, and (3) N2 and third nymphal instar (N3) engorge rapidly (minutes). With the exception of Ornithodoros hasei nymphs that depict flattened bodies, O. cerradoensis N1, N2, and N3 highly resemble homologous instars of other species in O. talaje sensu lato, therefore are not suitable for morphological comparisons within the group. In addition to morphological signature of larvae and adults that separate this new species; results of cross-mating attempts between O. cerradoensis and Ornithodoros guaporensis a morphologically and phylogenetically closely related species that also parasitizes rodents in the Brazilian Savannah; a Principal Component Analysis using larval characters; and a phylogenetic analysis using mitochondrial markers, support O. cerradoensis as an independent lineage within the Ornithodorinae.EEA RafaelaFil: Muñoz-Leal, Sebastián. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Medicina Veterinária Preventiva e Saúde Animal; BrasilFil: Martins, Maria Marlene. Universidade Federal de Uberlândia. Faculdade de Medicina Veterinária. Laboratório de Ixodologia; BrasilFil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Landulfo, Gabriel Alves Lves. Instituto Butantan. Laboratório de Parasitologia; BrasilFil: Simons, Simone Michaela. Instituto Butantan. Laboratório de Parasitologia; BrasilFil: Rodrigues, Vinícius Da Silva. Universidade Federal de Uberlândia. Faculdade de Medicina Veterinária. Laboratório de Ixodologia; BrasilFil: Ramos, Vanessa Do Nascimento. Universidade Federal de Uberlândia. Faculdade de Medicina Veterinária. Laboratório de Ixodologia; BrasilFil: Suzin, Adriane. Universidade Federal de Uberlândia. Faculdade de Medicina Veterinária. Laboratório de Ixodologia; BrasilFil: Szabó, Matías P.J. Universidade Federal de Uberlândia. Faculdade de Medicina Veterinária. Laboratório de Ixodologia; BrasilFil: Labruna, Marcelo B. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Medicina Veterinária Preventiva e Saúde Animal; Brasi