Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.799
Filtrar
1.
Exp Appl Acarol ; 85(1): 75-81, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34542738

RESUMO

Ixodid ticks represent vectors and reservoirs for a broad range of zoonotic pathogens. Collected ticks from field studies are therefore usually stored in ethanol, which in higher concentrations effectively inactivates most of the known tick-borne pathogens. Although commonly practiced as gold standard for inactivation, hardly any scientific data demonstrate that ethanol sufficiently penetrates the comparatively thick cuticula of ticks. Therefore, Amblyomma hebraeum tick pools were stored for 21 days in ethanol (96%). Afterwards, the ethanol was removed and the ticks were homogenized. Quantitative 1H-NMR spectroscopic analysis was applied to determine the residual concentration of ethanol inside the ticks. 1H-NMR spectroscopic analysis revealed that ethanol constituted 28.3-42.6 mg of the total weight of three ticks in the pools (89.9-121.5 mg). In addition, the low-pathogenic Hazara orthonairovirus (HAZV) was used as a cell culture model for this study. The virus was exposed to ethanol concentrations between 0 and 60% and incubated under various temperature conditions for four time periods. Afterwards, the residual virus infectivity was determined by titration. Following ethanol exposure, HAZV did not grow in cells after 9 h of exposure to an ethanol concentration of 25%. These results demonstrate an extremely low ethanol resistance of the virus, which was generally in line with previously reported ethanol inactivation data for Crimean-Congo hemorrhagic fever orthonairovirus (CCHFV). After prolonged storage and impregnation, comparable ethanol concentrations are achieved in the ticks, indicating the suitability of this inactivation method also for Bunyaviruses in ticks. At the very least, a massive virus inactivation can be assumed. Definitive proof of virus inactivation would require a bioassay of ethanol-treated infected ticks under appropriate biosafety conditions.


Assuntos
Vírus da Febre Hemorrágica da Crimeia-Congo , Febre Hemorrágica da Crimeia , Ixodidae , Orthobunyavirus , Amblyomma , Animais , Etanol
2.
BMC Res Notes ; 14(1): 326, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34433501

RESUMO

OBJECTIVES: Haemaphysalis longicornis is the most important tick species in Japan and has a wide range of vector capacity. Due to its veterinary and medical importance, this tick species has been used as a model for tick/vector biological studies. To identify the key molecules associated with physiological processes during blood feeding and embryogenesis, full-length cDNA libraries were constructed using the fat body, hemocytes-containing hemolymph, midgut, ovary and salivary glands of fed females and embryos of the laboratory colony of parthenogenetic H. longicornis. The sequences of cDNA from the salivary glands had been already released. However, the related information is still poor, and the other expressed sequence tags have not yet been deposited. DATA DESCRIPTION: A total of 39,113 expressed sequence tags were obtained and deposited at the DNA DataBank of Japan. There were 7745 sequences from embryos, 7385 from the fat body, 8303 from the hemolymph including hemocytes, 7385 from the midgut, and 8295 from the ovary. The data, including expressed sequence tags from the salivary glands was summarized into Microsoft Excel files. Sharing this data resource with the tick research community will be valuable for the identification of novel genes and advance the progress of tick research.


Assuntos
Ixodidae , Sequência de Aminoácidos , Animais , Sequência de Bases , Etiquetas de Sequências Expressas , Feminino , Biblioteca Gênica , Ixodidae/genética
3.
Exp Appl Acarol ; 84(4): 769-783, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34379235

RESUMO

In recent years, a new focus of the relict tick Haemaphysalis concinna was discovered in Western Poland, near Wolsztyn, Greater Poland voivodeship. This species may play an important role in the circulation of pathogens of medical and veterinary importance. In the present study we tested 880 juvenile ticks collected from rodents, including 427 H. concinna, 443 Ixodes ricinus and 10 Dermacentor reticulatus for three of the most common pathogens vectored by ticks in Poland: Rickettsia and Babesia spp. and Borrelia burgdorferi s.l. Additionally, molecular techniques were applied for accurate identification of tick host species (the voles Microtus and Alexandromys). Our study found differences in the range and prevalence of vectored pathogens between the three tick species. DNA of all three pathogens was found in I. ricinus. In juvenile H. concinna, DNA of Babesia microti, Borrelia afzelii and Rickettsia sp. was identified. Moreover, DNA of a new unnamed Babesia species related to B. crassa, was found in two H. concinna nymphs. This genotype of Babesia was previously identified in H. concinna in the Far East and then in Central Europe. DNA of Rickettsia raoulti and B. afzelii was detected in D. reticulatus nymphs. Among rodent hosts, Alexandromys oeconomus seems to be host of the highest significance for juvenile tick stages and was the only host species with B. afzelii detected in blood samples. Using phylogenetic methods, we confirmed a clear division between rodents from the genera Microtus and Alexandromys. Moreover, we found that A. oeconomus trapped in Western Poland clustered with a Central European A. oeconomus allopatric phylogroup.


Assuntos
Ixodes , Ixodidae , Rickettsia , Animais , Filogenia , Polônia , Rickettsia/genética
4.
Biomed Environ Sci ; 34(7): 581-586, 2021 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-34353424

RESUMO

Pathogens like bacteria and protozoa, which affect human and animal health worldwide, can be transmitted by vectors like ticks. To investigate the epidemiology and genetic diversity of bacteria and protozoans carried by ticks in Chengmai county of Hainan province, China, 285 adult hard ticks belonging to two species [ Rhipicephalus sanguineus ( sensu lato): 183, 64.21% and Rhipicephalus microplus: 102, 35.79%] from dogs, cattle, and goats were collected. Microbial families were identified in these ticks by amplifying the 18S rRNA, 16S rRNA ( rrs), citrate synthase ( gltA), and heat shock protein ( groEL) genes. Our data revealed the presence of four recognized species and two Candidatus spp. of Anaplasmataceae and Coxiellaceae. In sum, these data reveal an extensive diversity of Anaplasmataceae bacteria, Coxiellaceae bacteria, Babesiidae, and Hepatozoidae in ticks from Hainan Island, highlighting the need to understand the tick-borne pathogen infection in local animals and humans.


Assuntos
Anaplasmataceae/genética , Coccídios/genética , Coxiellaceae/genética , Insetos Vetores/microbiologia , Ixodidae/microbiologia , Piroplásmios/genética , Anaplasmataceae/isolamento & purificação , Animais , Chaperonina 60/genética , China , Citrato (si)-Sintase/genética , Coccídios/isolamento & purificação , Coxiellaceae/isolamento & purificação , Ilhas , Filogenia , Piroplásmios/isolamento & purificação , RNA Ribossômico 16S/genética , RNA Ribossômico 18S/genética
5.
Exp Appl Acarol ; 85(1): 113-129, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34431045

RESUMO

The southern cattle tick Rhipicephalus microplus is a major problem for the cattle industry in tropical and subtropical areas worldwide. Chemical products are commonly applied to control it; however, their indiscriminate use has resulted in the appearance of resistant lineages. In the last decades, plants have been used as an alternative to conventional acaricidal drugs, as several plant compounds repel activity, decrease the reproductive potential and reduce the survival rate of ticks. For this reason, the in vitro efficacy of hexanic and hydroalcoholic extracts of Randia aculeata, Moringa oleifera and Carica papaya were evaluated against the larvae and engorged females of R. microplus. Larval packet tests and adult immersion tests were performed with seven concentrations of each of the extracts. The extracts obtained with hydroethanolic solution (polar solvent) exhibited a higher acaricidal activity than extracts prepared with n-hexane (non-polar solvent). Hydroethanolic extracts of R. aculeata seed and shell showed the highest larvicidal activity against R. microplus (100 and 91% mortality, respectively) at a concentration of 100 mg/mL. Randia aculeata (seed and shell), M. oleifera and C. papaya treatments at the same concentration (100 mg/mL) also resulted in adult mortality of 85, 75, 66 and 55%, respectively. The adult immersion test showed that hydroethanolic extracts derived from R. aculeata seed significantly reduced the index of egg laying and increased the percentage inhibition of oviposition of female ticks at a concentration of 100 mg/mL. These results indicate that the tested extracts exhibit acaricidal activity and could be considered as potential agents for the development of alternative natural acaricides against R. microplus.


Assuntos
Acaricidas , Ixodidae , Plantas Medicinais , Rhipicephalus , Animais , Larva , Extratos Vegetais/farmacologia
6.
Exp Appl Acarol ; 85(1): 49-61, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34435267

RESUMO

The genetic population structure relationships of Hyalomma (Euhyalomma) lusitanicum in Andalusia (the south of the Iberian Peninsula) were examined using mtDNA sequence data from 887 bp of cytochrome oxidase subunit I (COI) gene. The sequence for the COI region was determined for 84 individuals collected in several localities of Andalusia, and 10 for other localities (i.e., five from Toledo, central Iberian Peninsula, four from Sicily (Italy) and one from Canary Island). Seventeen haplotypes were detected, including 27 polymorphic sites. The number of amino acid substitutions per site from mean diversity calculations for the entire population was 0.017. AMOVA analysis revealed a low gene flow that characterises the genetic population structure of this species in South Iberian Peninsula, with a haplotype diversity (h) value of 0.815. No geographically induced differentiation was observed, and separate evolutionary units were not detected. Our results indicate low genetic diversity across the geographical range of H. lusitanicum tick in Andalusia. Our data do not show any genetic discontinuity between the tick populations studied, including specimens from Canary Island and Sicily (Italy).


Assuntos
Complexo IV da Cadeia de Transporte de Elétrons , Ixodidae , Animais , Complexo IV da Cadeia de Transporte de Elétrons/genética , Genes Mitocondriais , Ixodidae/genética , Filogenia , Filogeografia
7.
Artigo em Inglês | MEDLINE | ID: mdl-34360274

RESUMO

Between March 2019 and February 2020, Asian long-horned ticks (Haemaphysalis longicornis Neumann, 1901) were discovered and collected for the first time in one middle and seven eastern Tennessee counties, facilitated by a newly developed passive and collaborative tick-surveillance network. Network collaborators included federal, state, county, university, and private resource personnel working with companion animals, livestock, and wildlife. Specimens were collected primarily from dogs and cattle, with initial detections of female adult stage ticks by stakeholders associated with parasitology positions (e.g., entomologists and veterinary parasitologists). Initial county tick detections were confirmed with morphological and molecular identifications, and then screened for the presence of animal-associated pathogens (Anaplasma marginale, Babesia species, Ehrlichia species, and Theileria orientalis), for which all tests were negative. Herein, we describe the identification and confirmation of these tick specimens as well as other results of the surveillance collaboration.


Assuntos
Ixodidae , Theileria , Doenças Transmitidas por Carrapatos , Carrapatos , Anaplasma , Animais , Bovinos , Cães , Feminino
8.
Exp Appl Acarol ; 84(4): 809-823, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34297228

RESUMO

Ticks are hematophagous ectoparasites and cause a major public health threat worldwide. Development of anti-tick vaccines is regarded to be an optimal alternative for tick control. AV422, a unique protein in ticks, is secreted into hosts during blood-feeding, but its roles are not confirmed in Haemaphysalis flava ticks. We retrieved a gene fragment encoding AV422 from a transcriptome dataset of H. flava, and based on it, we reconstructed the full length of AV422 from H. flava (Hf-AV422) by rapid amplification of cDNA ends. Expression profiles of Hf-AV422 in whole ticks and organs of different engorgement levels were determined by qPCR. Then its opening reading frame (ORF) was expressed in Escherichia coli strain BL21 (DE3). The prothrombin time (PT), activated partial thromboplastin time (APTT) and thrombin time (TT) assays were conducted to test anticoagulant activities of the purified recombinant protein (rHf-AV422). The full length of AV422 was 1152 bp. Hf-AV422 showed to be conserved as indicated by multiple sequence alignment. Expression of Hf-AV422 was significantly higher in salivary glands and cuticles than in ovaries. Its expression in whole ticks decreased during engorgement with the highest levels in 1/4 engorged ticks. rHf-AV422 prolonged PT, APTT and TT when incubated with rabbit plasma. Our data demonstrated that Hf-AV422 is a conserved salivary protein with anticoagulant activity. Further studies are needed to test in detail its functional properties to ensure it an adequate antigen candidate for the development of broad-spectrum vaccines against ticks.


Assuntos
Ixodidae , Carrapatos , Animais , DNA Complementar , Ixodidae/genética , Coelhos , Proteínas Recombinantes/genética , Transcriptoma
9.
Exp Appl Acarol ; 84(4): 785-794, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34231094

RESUMO

Hyalomma marginatum Koch is one of the main tick vectors of human and animal tick-borne diseases. The objective of this study was to establish standard procedures for rearing H. marginatum under laboratory conditions. Such laboratory tick populations are required to study acaricide resistance of Hyalomma ticks. In our rearing program, larvae and nymphs were fed on New Zealand white rabbits, whereas adults were fed on sheep. Non-parasitic stages were held at 18 and 28 °C to study the effect of temperature on development and survival. In our experiments, H. marginatum ticks have maintained the characteristics of a two-host life cycle. The engorged larvae did not detach and moulted on the rabbit, after which the emerged nymphs continued to feed on the same animal. The life cycle duration of H. marginatum was influenced by temperature, with each non-parasitic stage-i.e., larva and nymph molting-developing faster at 28 than at 18 °C; preoviposition and oviposition periods were shorter at 28 than at 18 °C. At 18 °C, no eggs hatched. The whole cycle from the collection of an engorged field tick until the emergence of second-generation larvae took 189 days. One such tick on average results in 3500 eggs which over time, taking into account the losses at each developmental stage, develop into 1200 adult ticks. Rearing these ticks a second generation therefore could result in millions of larval ticks.


Assuntos
Ixodidae , Carrapatos , Animais , Feminino , Laboratórios , Larva , Marrocos , Ninfa , Coelhos , Ovinos
10.
Rev Bras Parasitol Vet ; 30(3): e007221, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34259742

RESUMO

The state of Acre is in the western part of the Brazilian Amazon region and few studies involving ticks are available. The aim of the present study was to provide the first report of occurrence of Amblyomma latepunctatum and the second record of Ixodes luciae in Acre. Ticks were collected in October 2020 inside an open forested area in the municipality of Rio Branco, the state capital of Acre. Ixodid ticks were identified according to their external morphological characteristics. Three specimens were found on the vegetation by means of a visual search and were identified as Amblyomma scalpturatum (one male and one female) and Amblyomma latepunctatum (one male). Another specimen was found parasitizing a Didelphis marsupialis female that was caught using a Tomahawk trap; this was identified as Ixodes luciae (one male). This first report of A. latepunctatum in the state of Acre increases the number of species recorded here to 22. In addition, presence of I. luciae is confirmed in this state (second record), in the western Brazilian Amazon region.


Assuntos
Ixodes , Ixodidae , Amblyomma , Animais , Brasil , Feminino , Florestas , Masculino
11.
Vet Parasitol ; 298: 109490, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34271319

RESUMO

The objective of the present study was to determine the acaricidal activity of arecoline hydrobromide against cattle tick Rhipicephalus microplus infesting calves. in vivo efficacy of arecoline emulsified with polysorbate-80 (2%) was evaluated using ear bag method with the effective dose of 12.5 mg/mL applied on ear pinna of calves infested with ticks. Control group received polysorbate-80 (2%) after larvae infestation, however, reference group received deltamethrin (0.5 %). The experiment was continued for six days (144 h) and treatment of drug was given twice a day. Daily observation of calves was done to count the number of ticks after treatment. Acute dermal toxicity study for test drug was performed on wistar rats. Clinical safety of arecoline was determined by examining hematological profile and skin irritancy assay for calves infested with ticks. Results showed that arecoline significantly (p < 0.01) reduced the number of ticks attached to ear pinna of calves. Fewer number of ticks remained on calves skin at 120 h and 144 h were 8.09 and 6.21, respectively after treatment with arecoline in comparison to control group. Treatment of animals with arecoline hydrobromide significantly (p < 0.01) restored the hematological profile of animals as hemoglobin (Hb) level was 9.01 g/100 mL, PVC was 29.24 %, TEC and TLC were 5.23 and 7.19 106/cumm, respectively as compared to the control group having Hb 9.48 g/100 mL, PVC 31.60 %, TEC 5.64 106/cumm and TLC 7.27 106/cumm. Arecoline showed no toxicity while applied on wistar rats. The drug was mild irritative for an initial 20 min to the calves after that no redness or erythema was seen on the skin of the animals. Thus, arecoline hydrobromide may be an effective alternative to be used as herbal ectoparasiticide for the eradication of R. microplus ticks.


Assuntos
Acaricidas , Arecolina , Doenças dos Bovinos , Rhipicephalus , Infestações por Carrapato , Acaricidas/uso terapêutico , Acaricidas/toxicidade , Animais , Arecolina/uso terapêutico , Arecolina/toxicidade , Bovinos , Doenças dos Bovinos/tratamento farmacológico , Ixodidae , Ratos , Ratos Wistar , Pele/efeitos dos fármacos , Infestações por Carrapato/tratamento farmacológico , Infestações por Carrapato/veterinária
12.
Ticks Tick Borne Dis ; 12(5): 101746, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34091278

RESUMO

Ticks are one of the main vectors of pathogens for humans and animals worldwide. However, they harbor non-pathogenic microorganisms that are important for their survival, facilitating both their nutrition and immunity. We investigated the bacterial communities associated with two neotropical tick species of human and veterinary potential health importance from Brazil: Amblyomma aureolatum and Ornithodoros brasiliensis. In A. aureolatum (adult ticks collected from wild canids from Southern Brazil), the predominant bacterial phyla were Proteobacteria (98.68%), Tenericutes (0.70%), Bacteroidetes (0.14%), Actinobacteria (0.13%), and Acidobacteria (0.05%). The predominant genera were Francisella (97.01%), Spiroplasma (0.70%), Wolbachia (0.51%), Candidatus Midichloria (0.25%), and Alkanindiges (0.13%). The predominant phyla in O. brasiliensis (adults, fed and unfed nymphs collected at the environment from Southern Brazil) were Proteobacteria (90.27%), Actinobacteria (7.38%), Firmicutes (0.77%), Bacteroidetes (0.44%), and Planctomycetes (0.22%). The predominant bacterial genera were Coxiella (87.71%), Nocardioides (1.73%), Saccharopolyspora (0.54%), Marmoricola (0.42%), and Staphylococcus (0.40%). Considering the genera with potential importance for human and animal health which can be transmitted by ticks, Coxiella sp. was found in all stages of O. brasiliensis, Francisella sp. in all stages of A. aureolatum and in unfed nymphs of O. brasiliensis, and Rickettsia sp. in females of A. aureolatum from Banhado dos Pachecos (BP) in Viamão municipality, Brazil, and in females and unfed nymphs of O. brasiliensis. These results deepen our understanding of the tick-microbiota relationship in Ixodidae and Argasidae, driving new studies with the focus on the manipulation of tick microbiota to prevent outbreaks of tick-borne diseases in South America.


Assuntos
Amblyomma/microbiologia , Microbiota , Ornithodoros/microbiologia , Animais , Bactérias/genética , Bactérias/isolamento & purificação , Coxiella/genética , Coxiella/isolamento & purificação , DNA Bacteriano/isolamento & purificação , Francisella/genética , Francisella/isolamento & purificação , Ixodidae/microbiologia , Metagenômica , RNA Ribossômico 16S/genética , Rickettsia/genética , Rickettsia/isolamento & purificação
13.
Ticks Tick Borne Dis ; 12(5): 101754, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34126403

RESUMO

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.


Assuntos
Interações Hospedeiro-Parasita , Ixodidae/microbiologia , Rickettsia , Amblyomma/classificação , Animais , Evolução Biológica , Ecossistema , Evolução Molecular , Ninfa/microbiologia , Filogenia , Rickettsia/classificação , Rickettsia/genética , Rickettsia/isolamento & purificação , América do Sul , Infestações por Carrapato
14.
Ticks Tick Borne Dis ; 12(5): 101760, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34130147

RESUMO

Rhipicephalus sanguineus sensu lato (s.l.), commonly known as brown dog tick, is a widely distributed tick species that is substantially important for human and veterinary medicine. Therefore, it is the target of different control methods. Carvacrol and its semisynthetic derivative, acetylcarvacrol, are promising chemical compounds for alternative tick control. Thus, this study aimed to compare the repellent activities of carvacrol and acetylcarvacrol at different concentrations and drying times. Additionally, morphological alterations found in salivary glands were evaluated through histological techniques after exposure to acetylcarvacrol. The impact of the morphological changes on the development and survival of acini/cells in salivary glands was measured by a semiquantitative analysis. The repellent action of both compounds did not differ when evaluated at different concentrations, although acetylcarvacrol increased its effects as the concentration raised. Regarding the different drying times, acetylcarvacrol maintained its effects after 3 hours of exposure, while the efficacy of carvacrol decreased during this time period. Salivary glands of unfed R. sanguineus s.l. females showed dose-dependent alterations in the size and shape of acini as well as cytoplasmic vacuolization. Loss of the acinar cell limit, rupture of secretory granules and nuclear changes in the cells were also observed in the treated groups. Thus, our results demonstrated the potential of acetylcarvacrol to act as repellent against R. sanguineus s.l. Additionally, the morphological alterations found in salivary glands may interfere with the feeding process of ticks, which contributes to mitigate infestation by this species.


Assuntos
Cimenos/farmacologia , Ixodidae/efeitos dos fármacos , Glândulas Salivares/efeitos dos fármacos , Acaricidas/farmacologia , Animais , Cães , Repelentes de Insetos/farmacologia , Rhipicephalus sanguineus/efeitos dos fármacos , Glândulas Salivares/patologia , Controle de Ácaros e Carrapatos/métodos , Infestações por Carrapato/veterinária
15.
Ticks Tick Borne Dis ; 12(5): 101757, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34147920

RESUMO

The prevention of tick-borne diseases is a major challenge for livestock production globally. Tick control strategies include the use of acaricides, but the prescribed strategies do not achieve the desired results in several countries, including Kenya. To better understand how tick treatment practices, contribute to reported tick treatment failures, we assessed livestock owners' acaricide procurement, level of knowledge about acaricides and tick resistance, and how they apply acaricides. We also assessed the quality of the commonly available acaricides. We focused on three livestock systems in Laikipia County, Kenya: two private ranches; one community ranch whose members communally graze their cattle and acquire and apply acaricides; and individual livestock owners in two pastoral communities who individually graze their cattle and acquire and apply acaricides. Through interviews and focus group discussions we assessed; access to acaricides, livestock owners' knowledge, and acaricide use practices; interview data were triangulated with participant observations (n = 107). We analysed nine commonly used acaricides to determine the active ingredient concentration and we determined the concentration of active ingredients in acaricide dilutions collected on farms. All livestock owners had access to and used chemical acaricides for tick control, predominantly amitraz-based. Private ranchers bought one amitraz-based acaricide in bulk directly from the manufacturer, while all other livestock owners bought from agrovet shops. The livestock owners acquired knowledge about acaricides from their own experiences and through experience-based recommendations from peers, but not from the technical information provided by the manufacturers and agrovet shops. All pastoral livestock frequently changed acaricide brand and active ingredient class. A large majority of pastoralists (86%) mixed acaricide brands within and across active ingredient classes; a smaller majority (56%) mixed acaricides with crop pesticides and insecticides. Our lab tests confirmed the content description on the labels bought from agrovet shops. However, on-farm acaricide dilutions from all three livestock systems deviated from the level recommended for effective treatment. If too diluted, the acaricide does not kill ticks, promoting resistance development. If too concentrated, this increases environmental contamination and raises public health concerns. Livestock owners lack a technical understanding of the functioning of acaricides, compromising their use and effectiveness. The widely adopted mixing of acaricides with insecticides and pesticides raises serious health concerns.


Assuntos
Acaricidas , Fazendas , Controle de Ácaros e Carrapatos/métodos , Acaricidas/efeitos adversos , Acaricidas/farmacologia , Animais , Bovinos , Doenças dos Bovinos/prevenção & controle , Poluição Ambiental , Fazendeiros , Humanos , Resistência a Inseticidas , Inseticidas/efeitos adversos , Inseticidas/farmacologia , Ixodidae/efeitos dos fármacos , Quênia , Saúde Pública , Piretrinas/farmacologia , Rhipicephalus/efeitos dos fármacos , Inquéritos e Questionários , Infestações por Carrapato/prevenção & controle , Infestações por Carrapato/veterinária , Toluidinas/farmacologia
16.
Exp Appl Acarol ; 84(3): 585-591, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34109509

RESUMO

Ixodes ricinus is the most abundant tick species and an important vector of pathogens in Germany and in large parts of Europe. A few other ixodid tick species, e.g., Dermacentor reticulatus, may also be of eco-epidemiological relevance. As ticks are not only found in natural but also in suburban areas (parks, gardens), the present study investigated whether ticks occur on and near football grounds thus posing a potential risk to players and visitors. Thirty-two football grounds from all 16 German federal states were selected, mainly situated adjacent to a green area (forest, park). Ticks were collected by the conventional flagging method in spring 2018, and nymphs and adults were counted and morphologically determined. Altogether 807 nymphal and adult ticks were collected from 29 football grounds: 714 I. ricinus, 64 Ixodes inopinatus, 2 Ixodes frontalis, 24 Ixodes sp. ticks, and 3 D. reticulatus. Ixodes inopinatus was found in 13 out of 16 German states. Three ticks were even found on the turf of two football fields. It can be concluded that ticks occur quite frequently and sometimes in high abundance near football grounds situated close or adjacent to a forest or a park.


Assuntos
Dermacentor , Futebol Americano , Ixodes , Ixodidae , Animais , Europa (Continente) , Alemanha
17.
Exp Appl Acarol ; 84(3): 637-657, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34146230

RESUMO

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) has recently emerged as an alternative to morphological and molecular tools to identify tick species. In this study, we set out to evaluate and confirm the ability of MALDI-TOF MS to identify different species of ticks collected in the Democratic Republic of the Congo and preserved in 70% ethanol. A total of 575 ticks, of which 530 were collected from domestic pigs and 45 from wild animals, were subjected to MALDI-TOF MS analysis to evaluate the intraspecies reproducibility and interspecies specificity of MS profiles obtained from the different species. Morphologically, the ticks belonged to seven different species, namely Rhipicephalus complanatus, Rhipicephalus congolensis, Haemaphysalis muhsamae, Ixodes cumulatimpunctatus, Amblyomma exornatum, Amblyomma compressum and an unidentified Rhipicephalus sp. A total of 535/575 (93%) of the spectra obtained were of good enough quality to be used for our analyses. Our home-made MALDI-TOF MS arthropod database was upgraded with spectra obtained from between one and five randomly selected specimens per species. For these reference specimens, molecular identification of the ticks was also made using 16S, 12S rDNA genes and the Cox1 mtDNA gene sequencing. The remaining good quality spectra were then queried against the upgraded MALDI-TOF MS database, showing that 100% were in agreement with the morphological identification, with logarithmic score values (LSVs) between 1.813 and 2.51. The consistency between our morphological, molecular and MALDI-TOF MS identification confirms the capability and precision of MALDI-TOF MS for tick identification.


Assuntos
Animais Selvagens , Ixodidae , Animais , República Democrática do Congo , Reprodutibilidade dos Testes , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
18.
Exp Appl Acarol ; 84(3): 659-672, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34138398

RESUMO

We herein describe zebuine cattle tick infestation in a farm in southeast Brazil with an examination accurate enough to detect tick immatures and species other than R. microplus. Cattle were inspected monthly for ticks from May 2015 to May 2017 and 7604 ticks were collected along 276 bovine inspections. Rhipicephalus microplus was the dominant species (7197 specimens, 94.5% from the total), but Amblyomma sculptum was also collected (407/5.5%). Horse tick infestations were evaluated for comparison purposes of A. sculptum infestations of a primary host sharing pastures with bovines. Ticks were counted on the left side of 4-12 horses every 3 months from October 2015 to October 2017. Overall, 68 horse inspections were performed and 1702 ticks were collected: Dermacentor nitens (805 specimens/47.3% of the total), A. sculptum (733/43.1%) and R. microplus (164/9.6%). Overall mean tick abundance on bovines was low if compared to that of taurine cattle and counting revealed four annual generations of R. microplus. The interval between infestation peaks was 3 months, irrespective of the season, and an increase in tick counts from spring onward, as described in the south of Brazil, was not seen. Amblyomma sculptum infestation abundance was minor but constant and in high prevalence. Cattle infestation with A. sculptum seems to depend on pasture sharing with other domestic and wild hosts that are its primary hosts and provide engorged females to complete their life cycle. The impact of such tick sharing among several host species on tick-borne pathogen transmission remains to be elucidated.


Assuntos
Doenças dos Bovinos , Ixodidae , Rhipicephalus , Infestações por Carrapato , Amblyomma , Animais , Brasil/epidemiologia , Bovinos , Doenças dos Bovinos/epidemiologia , Fazendas , Feminino , Infestações por Carrapato/epidemiologia , Infestações por Carrapato/veterinária
19.
Exp Appl Acarol ; 84(3): 607-622, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34148204

RESUMO

Smartphone cameras and digital devices are increasingly used in the capture of tick images by the public as citizen scientists, and rapid advances in deep learning and computer vision has enabled brand new image recognition models to be trained. However, there is currently no web-based or mobile application that supports automated classification of tick images. The purpose of this study was to compare the accuracy of a deep learning model pre-trained with millions of annotated images in Imagenet, against a shallow custom-build convolutional neural network (CNN) model for the classification of common hard ticks present in anthropic areas from northeastern USA. We created a dataset of approximately 2000 images of four tick species (Ixodes scapularis, Dermacentor variabilis, Amblyomma americanum and Haemaphysalis sp.), two sexes (male, female) and two life stages (adult, nymph). We used these tick images to train two separate CNN models - ResNet-50 and a simple shallow custom-built. We evaluated our models' performance on an independent subset of tick images not seen during training. Compared to the ResNet-50 model, the small shallow custom-built model had higher training (99.7%) and validation (99.1%) accuracies. When tested with new tick image data, the shallow custom-built model yielded higher mean prediction accuracy (80%), greater confidence of true detection (88.7%) and lower mean response time (3.64 s). These results demonstrate that, with limited data size for model training, a simple shallow custom-built CNN model has great prospects for use in the classification of common hard ticks present in anthropic areas from northeastern USA.


Assuntos
Ixodes , Ixodidae , Amblyomma , Animais , Feminino , Masculino , Redes Neurais de Computação , Ninfa
20.
Parasit Vectors ; 14(1): 330, 2021 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-34158107

RESUMO

BACKGROUND: The tick Haemaphysalis longicornis (Neumann) is a well-known vector of numerous pathogens of veterinary and medical importance. Various control strategies, including the use of synthetic pesticides, have been developed to control this tick species. However, demand for effective and safe alternative pesticides is increasing due to the adverse effects associated with the intensive and injudicious use of synthetic pesticides, which include undesirable effects on non-target species and environmental pollution. Hence, the acaricidal activity of the extract and the essential oil of Cinnamomum cassia (Chinese cinnamon) and their major components, and the underlying mechanisms of this activity, were evaluated against unfed larvae and nymphs of H. longicornis. METHODS: The components of the extract and essential oil of C. cassia were determined by gas chromatography-mass spectrometry, and their larvicidal and nymphicidal activity were evaluated using the larval and nymphal packet test. The underlying detoxification mechanism was elucidated by targeting in vivo esterase and monooxygenase activity, and the toxicological effect was assessed on non-target Tenebrio molitor and Harmonia axyridis by topical application in open Petri dishes. RESULTS: (E)-cinnamaldehyde was the predominant component of the extract (50.79%) and essential oil (89.95%). The 50% lethal concentration (LC50) for larvae and nymphs treated with the extract was 11.56 and 49.18 mg/mL, respectively. The essential oil, (E)-cinnamaldehyde and fenvalerate exhibited acaricidal activity, with LC50 values of 3.81, 3.15, and 0.14 mg/mL, respectively, against the larvae, and 21.31, 16.93, and 1.89 mg/mL, respectively, against the nymphs. (E)-cinnamaldehyde significantly increased esterase and monooxygenase activity in both larvae and nymphs. Unlike fenvalerate, C. cassia essential oil and (E)-cinnamaldehyde did not cause mortality of T. molitor or H. axyridis adults. CONCLUSIONS: This study demonstrates that C. cassia essential oil and (E)-cinnamaldehyde have the potential to be developed into botanical-based larvicidal and nymphicidal agents for tick control.


Assuntos
Acaricidas/farmacologia , Acroleína/análogos & derivados , Cinnamomum aromaticum/química , Ixodidae/efeitos dos fármacos , Óleos Voláteis/farmacologia , Extratos Vegetais/farmacologia , Acaricidas/química , Acroleína/análise , Acroleína/farmacologia , Animais , Feminino , Ixodidae/crescimento & desenvolvimento , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Masculino , Óleos Voláteis/química , Extratos Vegetais/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...