RESUMO
The identification and characterization of tick proteins allow us to discover new physiological targets useful for the development of tick control methods. Bm05br (Brazil Rhipicephalus microplus protein 05) is a protein with unknown function identified in the saliva of R. microplus. Rs05br (Brazil Rhipicephalus sanguineus protein 05), a protein with 99â¯% similarity to Bm05br, was identified in Rhipicephalus linnaei egg, larval, and nymphal stages, as well as in adult saliva. To improve the knowledge about both proteins, immunological characterization was performed, including antigenicity analysis, vaccination trials, and artificial feeding. The sequence and antigenicity analysis of Bm05br and Rs05br proteins showed that R. linnaei could serve as a tick model for cross-protection studies. The recombinant Bm05br protein was immunogenic. Anti-Bm05br antibodies recognized the homologous protein Rs05br in different stages, organs, and in the saliva of R. linnaei. Although rBm05br did not induce a protective response against infestation in R. linnaei in this study, further experiments could be developed taking into account new formulations and animal models for vaccination. These results also serve as a reference for future research on the function of these proteins in R. microplus and R. linnaei physiology, as well as other species of the genus Rhipicephalus.
Assuntos
Proteínas de Artrópodes , Rhipicephalus , Infestações por Carrapato , Animais , Rhipicephalus/imunologia , Rhipicephalus/química , Proteínas de Artrópodes/imunologia , Proteínas de Artrópodes/genética , Proteínas de Artrópodes/química , Infestações por Carrapato/veterinária , Infestações por Carrapato/parasitologia , Infestações por Carrapato/imunologia , Infestações por Carrapato/prevenção & controle , Feminino , Proteínas Recombinantes/imunologia , Coelhos , Larva/imunologia , Saliva/imunologia , Saliva/química , Sequência de AminoácidosRESUMO
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.
RESUMO
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.
Assuntos
Amblyomma , Rickettsia , Animais , Colômbia/epidemiologia , Filogenia , Rickettsia/genética , Reação em Cadeia da Polimerase em Tempo RealRESUMO
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.
RESUMO
Background: Trypanosoma evansi is the most common protozoan in tropical and subtropical regions of the world, due to its ability to maintain and be transmitted by vectors such as Stomoxys spp. and Tabanus spp. This protozoan causes high morbidity and mortality rates in horses in African, American and Asian countries. In the years 2021 and 2022, a high mortality rate was reported among horses with symptoms associated with Trypanosoma spp. in the municipality of Arauca, department of Arauca, Colombia. The investigation described here was therefore carried out, seeking to identify the pathogens and risk factors that led to the death of the horses in this region of Colombia. Cases: Blood samples were collected from Colombian criollo horses and dogs, as were samples of ticks, flies and horseflies that infested the horses. A variety of tissue samples were removed from the horses a few min after their death for histopathological analysis. Two questionnaires were applied to obtain information about the horses and the environment in which they live. The results of the clinical examination revealed pale mucous membranes, jaundice, high fever, dehydration and lethargy. The horses were also infested with Amblyomma mixtum (17.6%) and Dermacentor nitens (82.4%) ticks, and with Tabanus pungens (74%), Tabanus spp. (26%), and Stomoxys calcitrans flies (100%), while the dogs were infested with Rhipicephalus sanguineus s.l. (77.7%) and Amblyomma mixtum (22.2%) ticks. The blood smear test results revealed the presence of Trypanosoma spp. in 66.6% (n = 4) of the horse blood samples, and in 50% (n = 1) of the dog blood samples. PCR performed to identify the Trypanosoma species confirmed the presence of T. evansi. Histological examination of the spleen revealed the involvement and dissemination of T. evansi in the tissues. The horses also showed the presence of Equine Infectious Anemia Virus (EIAV). Discussion: This is the first updated specific report of T. evansi in criollo horses in the savannah flood zone of the municipality of Arauca, Colombia. The main risk associated with T. evansi infection in horses was found to be infestation with the natural vector T. pungens and the mechanical vector S. calcitrans, which are efficient ectoparasites for the transmission of this parasite. The presence of T. evansi in dogs represents a constant risk to horses, because dogs may serve as a reservoir for the maintenance of the hemoparasite in the population under study. Another risk factor for horses could be the presence of vampire bats (Desmodus rotundus), a species of bat that has been described as a vector and reservoir of T. evansi in Colombia. The presence of EIAV antibodies in the horses under study can be attributed to the exposure of sick horses to vectors of this virus, such as Tabanus spp., S. calcitrans and inanimate needle-shaped fomites. This is the first study that identifies the coinfection of T. evansi and EIAV in horses in the floodplain region of Colombia. In view of the importance of these 2 pathologies to the health of horses, a greater number of tests and a larger animal population will be required to determine if this coinfection is the cause of the death of criollo horses in this region of Colombia. Lastly, the owners reported that pharmacological control with trypanocides has not been successful in most of the outbreaks that occurred during the years 2021 and 2022. This may suggest that Trypanosoma evansi is developing resistance to these drugs; therefore, specific studies will be required in the future to test this hypothesis.
Assuntos
Animais , Trypanosoma/isolamento & purificação , Fatores de Risco , Vírus da Anemia Infecciosa Equina/isolamento & purificação , Cavalos/parasitologia , ColômbiaRESUMO
In Colombia, the control of the cattle tick Rhipicephalus (Boophilus) microplus lies almost exclusively on the use of chemical acaricides. However, R. (B.) microplus has developed resistance to most of the commercially available products. The aim of this study was to assess the degree of resistance to the major topical acaricides used in Colombia. The adult immersion test was used as recommended by FAO with ticks from 7 farms originating in 4 distant Colombian regions. The efficacy of the products was calculated based on the reproductive parameters of fecundity and fertility with groups of ticks (n = 40) exposed to the recommended concentrations of each acaricide, and compared with the respective control group exposed to distilled water. In general, products containing deltamethrin (25 ppm) and amitraz (208 ppm) were less effective, with efficacy values of <20% and 10-50%, respectively. Doubling the concentration did not increase the efficacy of either compound. The combination of chlorpyrifos (312 ppm) + cypermethrin (150 ppm) showed great variation between farms, with an efficacy ranging between 22-93%. Unlike chlorpyrifos, the organophosphorus ethion (622 ppm) was 99-100% effective in completely inhibiting oviposition in 4 of the 7 farms. In conclusion, resistance to deltamethrin and amitraz is very high in seven distant strains of the Colombian territory, varies widely for chlorpyrifos, and was not detected for ethion that was 99-100% effective
El control de la garrapata Rhipicephalus (Boophilus) microplus en Colombia radica casi exclusivamente en el uso de acaricidas químicos. Sin embargo, R. (B.) microplus ha desarrollado resistencia a la mayoría de los productos actualmente disponibles comercialmente. El objetivo de este estudio fue valorar el grado de resistencia a concentraciones recomendadas de los principales acaricidas comerciales de uso tópico en Colombia. Se empleó la prueba de inmersión de adultas (teleoginas) recomendada por la FAO con garrapatas procedentes de siete predios localizados en cuatro departamentos colombianos. La eficacia de los productos se calculó con base en los parámetros reproductivos de fecundidad y fertilidad con grupos de garrapatas (n=40) expuestas a cada acaricida, comparándolos con el respectivo grupo control expuesto a agua destilada. En general, los productos de deltametrina (25 ppm) y amitraz (208 ppm) fueron los menos efectivos, con valores de eficacia de <20% y de entre 10-50%, respectivamente. Tampoco se observó un aumento de eficacia al doblar la concentración de ambos compuestos por separado. La combinación de clorpirifos (312 ppm) + cipermetrina (150 ppm) mostró gran variación entre fincas, con una eficacia de entre el 22-93%. A diferencia del clorpirifos, el organofosforado etión (622 ppm) sí produjo un 99-100% de eficacia inhibiendo completamente la oviposición en cuatro de las siete fincas. En conclusión, la resistencia a deltametrina y amitraz es muy alta en siete poblaciones distantes del territorio colombiano; en cuanto al clorpirifos varía mucho, y éste no parece tener resistencia cruzada con el etión que fue el de mayor eficacia.
O controle do carrapato Rhipicephalus (Boophilus) microplus na Colô mbia está focado quase exclusivamente no uso de acaricidas químicos. Porém, R. (B.) microplus tem desenvolvido resistência à maioria dos produtos disponíveis comercialmente. O objetivo deste estudo foi valorar o grau de resistência às concentrações recomendadas dos principais acaricidas comerciais de uso tópico na Colô mbia. Foi usada a prova da imersã o de adultas (teleoginas) recomendada pela FAO com carrapatos procedentes de 7 fazendas localizadas em 4 departamentos colombianos. A eficácia dos produtos calculou-se com base nos parâmetros reprodutivos de fecundidade e fertilidade com grupos de carrapatos (n=40) expostos a cada acaricida. Em geral, os produtos deltametrina (25 ppm) e amitraz (208 ppm) foram os menos efetivos, com valores de eficácia de <20% e de entre 10-50%, respectivamente. Também nã o foi observado aumento da eficácia ao dobrar a concentraçã o de ambos produtos por separado. A combinaçã o de clorpirifos (312 ppm) + cipermetrina (150 ppm) mostrou uma grande variaçã o entre as fazendas, com uma eficácia de 22-93%. Diferentemente do clorpirifos, o organofosforado etion (622 ppm) teve um 99-100% de eficácia por inibiçã o completa da ovoposiçã o em 4 das 7 fazendas. Em conclusã o, a resistência à deltametrina e amitraz é muito alta em 7 populações distantes do território colombiano; quanto ao clorpirifos, varia muito e este nã o parece ter resistência cruzada com o etion que foi o de maior eficácia.<20% e de entre 10-50%, respectivamente. Também não foi observado aumento da eficácia ao dobrar a concentração de ambos produtos por separado. A combinação de clorpirifos (312 ppm) + cipermetrina (150 ppm) mostrou uma grande variação entre as fazendas, com uma eficácia de 22-93%. Diferentemente do clorpirifos, o organofosforado etion (622 ppm) teve um 99-100% de eficácia por inibição completa da ovoposição em 4 das 7 fazendas. Em conclusão, a resistência à deltametrina e amitraz é muito alta em 7 populações distantes do território colombiano; quanto ao clorpirifos, varia muito e este não parece ter resistência cruzada com o etion que foi o de maior eficácia.