Resistance to deltamethrin and its association with mutation sites in the sodium iron channel domain III gene in Rhipicephalus microplus in Huaihua City of Hunan Province / 中国血吸虫病防治杂志

Objective To investigate the level of deltamethrin resistance and mutation sites in the sodium iron channel gene in Rhipicephalus microplus in Huaihua City, Hunan Province, and to examine the correlation between deltamethrin resistance and mutation sites in the sodium iron channel gene in Rh. microplus. Methods Rh. microplus was sampled from multiple yellow cattle farms in Huaihua City, Hunan Province from June to September 2022, and the level of resistance to deltamethrin was determined in ticks using the adult immersion test. The sodium iron channel domain III gene was amplified in deltamethrin-resistant and wild-type Rh. microplus using PCR assay. Following sequencing and sequence alignment, mutation sites were detected in bases. The sodium iron channel domain III gene in Rh. microplus was translated, and the signal peptide, transmembrane domain, and phosphorylation and glycosylation sites were detected in amino acid sequences. The tertiary structures of the sodium iron channel domain III protein of deltamethrin-resistant and wild-type Rh. microplus were deduced and compared, and the association be tween mutation sites in bases and resistance to deltamethrin was examined in Rh. microplus according the level of deltamethrin resistance, sequence alignment and protein tertiary structure. Results The median (LC50) and 95% lethal concentrations (LC95) of deltamethrin were 121.39 mg/L and 952.61 mg/L against Rh. microplus, with a resistance factor of 9.24 and level II resistance. The sequence of the sodium ion channel domain III gene was 1 010 bp in size, and mutation sites were detected in two neighboring bases in the sequence of the sodium ion channel domain III gene in deltamethrin-resistant Rh. microplus. Although no signal peptides were found in the sodium iron channel domain III protein of deltamethrin-resistant or wild-type Rh. microplus, 6 trans-membrane domains, 42 phosphorylation sites and 8 glycosylation sites were identified, with a significant difference in the tertiary structure of the sodium iron channel domain III protein between deltamethrin-resistant and wild-type Rh. microplus. Conclusions Level II resistance to deltamethrin is detected in Rh. microplus in Huaihua City, Hunan Province, and two mutation sites that correlate with the emergence of deltamethrin resistance are identified in the sequence of the sodium iron channel domain III gene in deltamethrin-resistant Rh. microplus.

Sequence characteristics of Rhipicephalus microplus Enolase gene and prediction of structure and antigenic epitopes of its encoding protein / 中国血吸虫病防治杂志

Objective To analyze the sequence characteristics of Rhipicephalus microplus Enolase gene, and to predict the secondary and tertiary structure and antigenic epitopes of the Enolase protein. Methods Sixty-two engorged female R. microplus were sampled from a yellow cattle breeding farm in Zhijiang County, Huaihua City, Hunan Province in June 25, 2022. Genomic DNA was isolated from R. microplus, and the Enolase gene was amplified using PCR assay, followed by cloning, sequencing and expression of the amplification product. The sequence characteristics of the Enolase gene were analyzed using the software Clustal X, and the gene sequence was translated into amino acid sequences. The secondary and tertiary structures of the Enolase protein were deduced using the software PRABI, and the physicochemical properties of the Enolase protein were analyzed using the software PRABI. In addition, the B- and T-cell epitopes of the Enolase protein were predicted using the software ABCpred Prediction, Scratch, IEDB and NetCTL. Results The R. microplus Enolase gene sequence was 1 323 bp in size, and the contents of A, T, G and C bases were 24.5%, 22.5%, 27.0% and 26.0%,with 47.0% of A + T content and 53.0% of G + C content. The R. microplus Enolase gene encoded 434 amino acids, and the Enolase protein had a molecular weight of 47.12 kDa. The secondary structure of the Enolase protein contained 186 α-helixes (42.86%), 32 β-turns (7.37%), 144 random coils (33.18%) and 72 extended strands (16.59%). The Enolase protein was most probably present in cytoplasm (76.7%), followed by in mitochondrion (39.1%) and nucleus (21.7%), and the Enolase protein had no signal peptide or transmembrane domain. In addition, the Enolase protein had 14 B-cell dominant epitopes and 8 T-cell dominant epitopes. Conclusions The R. microplus Enolase gene sequence exhibits a GC preference, and its encoding Enolase protein is an acidic and hydrophilic protein, with α-helixes and random coils as its primary structure, and presenting B- and T-cell dominant epitopes, which is a potential target for development of vaccines against R. microplus.

Influence of agricultural extension activities on tick control among cattle on family dairy farms in the southeast Brazil

The aim of the present study was to evaluate the resistance of tick populations on 16 family farms that were members of the agricultural producers' cooperative of the São Pedro region of the state of São Paulo (COOPAMSP). Bioassays were conducted on nine commercial products in 2018 and 2019. Their active agents were as follows: deltamethrin, amitraz, cypermethrin + chlorpyrifos + citronella, cypermethrin + chlorpyrifos + fenthion, cypermethrin + chlorpyrifos + piperonyl butoxide, dichlorvos + chlorpyrifos, cypermethrin, chlorfenvinphos + dichlorvos, and ivermectin. On some farms, a larval packet test (LPT) was also performed. Overall, four acaricides presented mean efficacy greater than 89%, among which two were associations of pyrethroids + organophosphates and two were associations of organophosphates + organophosphates. Deltamethrin, cypermethrin and ivermectin presented mean efficacy lower than 50%. In the bioassays using the LPT, all five farms showed resistance to diazinon, while only one farm presented resistance to cypermethrin. The results were handed over to each farmer with appropriate guidance for treatments. This study demonstrated that the important points to be implemented related directly to use control strategies, based on direct assistance for farmers and diagnosis of tick population sensitivities.

Effects of climate changes on the distribution of Rhipicephalus microplus in China / 中国血吸虫病防治杂志

Objective To identify the environmental factors affecting the geographical distribution of Rhipicephalus microplus in China, and to examine the impact of climate changes on the distribution of R. microplus in China. Methods The national and international publications pertaining to the geographical distribution of R. microplus in China were retrieved, and the geographical location was extracted. The suitable habitats of R. microplus and the dominant environmental factors affecting the distribution of suitable habitats of R. microplus were predicted in China based on the geographical data and environmental variables using the ArcGIS 10.7 software and the maximum entropy model. Results Among the main climatic factors affecting the geographical distribution of R. microplus in China, the factors contributing more than 10% to the suitable habitats of R. microplus mainly include the annual mean precipitation (38.2%), the average temperature of the coldest quarter (28.4%) and the precipitation of the driest month (14.2%). The current suitable habitats of R. microplus were mainly found in southern China, and the high-, medium- and low-suitable areas accounted for 8.6%, 13.1% and 10.5% of the total land area of China, respectively. The suitable habitats of R. microplus were predicted to increase by 399 800 km2 in China using the maximum entropy model under the RCP 4.5 emissions scenario in 2070, and the emerging suitable habitats were mainly distributed in Gansu Province, Ningxia Hui Autonomous Region, Qinghai Province, Hebei Province, Shaanxi Province, Liaoning Province, Inner Mongolia Autonomous Region, Shandong Province, Sichuan Province and Tibeten Autonomous Region. In addition, the suitable habitats of R. microplus were predicted to show an overall expansion towards northward from present to 2070. Conclusions Climate changes affect the distribution of suitable habitats of R. microplus in China, and annual mean precipitation may be a key factor affecting the distribution of suitable habitats of R. microplus.

Use of anti-tick drugs in dairy farms in the microregion of Alfenas, Minas Gerais, Brazil / Uso de carrapaticidas em fazendas leiteiras na microrregião de Alfenas, Minas Gerais, Brasil

Abstract Ectoparasitic infestation in dairy cattle, the most common being Rhipicephalus (Boophilus) microplus, causes significant loss in production. The control of ectoparasites often occurs incorrectly, resulting in resistance to the active ingredients and residues in milk. To understand of acaricide use in the microregion of Alfenas, Minas Gerais (Brazil), questionnaires were applied to the owners of 100 dairy farms in the region and were selected randomly. Dairy farms were allocated according to production scale: up to 150 liters/day, 151-400 liters/day and more than 400 liters/day. The interviewees were asked about production characteristics, acaricide management and active ingredients. The interview answers were subjected to descriptive analysis. Results showed that all properties, independent of production-scale, used acaricides. The most cited was: Cypermethrin Chlorpyrifos Citronellal (31%), Fluazuron (18.6%) and Fipronil (17%). Among the interviewed, 41,1% use drugs that have restrictions that are not allowed in legislation for use in lactating dairy cows (fluazuron, fipronil, ivermectin). 15% affirmed they weren't aware of the "withdrawal period" of medication and 73% change in the active ingredient used. In order to revert this antiparasitic drug's resistance situation and contamination of milk with drug residues, it is necessary to focus on the awareness of milk producers and training of labor.

Resumo A infestação por ectoparasitas em bovinos leiteiros, sendo o mais comum o Rhipicephalus (Boophilus) microplus, causa prejuízos significativos na produção. No entanto, o controle dos ectoparasitas geralmente ocorre incorretamente, resultando em resistência aos princípios ativos e presença de resíduos no leite. Para entender os padrões de uso de acaricidas na microrregião de Alfenas, Minas Gerais, Brasil, foram aplicados questionários aos proprietários de 100 fazendas leiteiras que foram classificadas de acordo com uma escala de produção: até 150 litros/dia, de 151 a 400 litros/dia e mais de 400 litros/dia. Os entrevistados foram questionados sobre características da produção, manejo do acaricida de gado e conhecimento sobre os princípios ativos. Todas as propriedades, independentemente da escala de produção, usavam acaricidas. Foram citados com maior frequência: Cipermetrina + Clorpirifós + Citronelal (31%), Fluazuron (18.6%) e Fipronil (17%). Entre os produtores entrevistados, 41,1 % fazem uso de drogas com restrição que não são atualmente permitidas na legislação para uso em vacas em lactação (fluazuron, fipronil, ivermectina). 15% dos produtores de leite afirmaram não estar cientes do "período de carência" dos medicamentos; outros relatam trocas constantes do princípio ativo utilizado. Para reverter a situação do uso indiscriminado de antiparasitários, é necessário focar na conscientização dos produtores de leite e na formação do trabalho.

Effects of essential oils on native and recombinant acetylcholinesterases of Rhipicephalus microplus / Efeito de óleos essenciais sobre acetilcolinesterases nativa e recombinante de Rhipicephalus microplus

Abstract This study reports the action of essential oils (EO) from five plants on the activity of native and recombinant acetylcholinesterases (AChE) from Rhipicephalus microplus. Enzyme activity of native susceptible AChE extract (S.AChE), native resistant AChE extract (R.AChE), and recombinant enzyme (rBmAChE1) was determined. An acetylcholinesterase inhibition test was used to verify the effect of the EO on enzyme activity. EO from Eucalyptus globulus, Citrus aurantifolia, Citrus aurantium var.dulcis inhibited the activity of S.AChE and R.AChE. Oils from the two Citrus species inhibited S.AChE and R.AChE in a similar way while showing greater inhibition on R.AChE. The oil from E. globulus inhibited native AChE, but no difference was observed between the S.AChE and R.AChE; however, 71% inhibition for the rBmAChE1 was recorded. Mentha piperita oil also inhibited S.AChE and R.AChE, but there was significant inhibition at the highest concentration tested. Cymbopogon winterianus oil did not inhibit AChE. Further studies are warranted with the oils from the two Citrus species that inhibited R.AChE because of the problem with R. microplus resistant to organophosphates, which target AChE. C. winterianus oil can be used against R. microplus populations that are resistant to organophosphates because its acaricidal properties act by mechanism(s) other than AChE inhibition.

Resumo Este estudo relata a ação de óleos essenciais de cinco plantas na atividade de acetilcolinesterases (AChE) nativas e recombinantes de Rhipicephalus microplus. A atividade enzimática do extrato de acetilcolinesterase nativa suscetível (S.AChE) e resistente (R.AChE) e da enzima recombinante (rBmAChE1) foi determinada. Um teste de inibição da AChE foi utilizado, para verificar o efeito dos óleos essenciais sobre a atividade enzimática. Óleos essenciais de Eucalyptus globulus, Citrus aurantifolia, Citrus aurantium var. dulcis inibiram a atividade de S.AChE e R.AChE. Os óleos das duas espécies de Citrus inibiram S.AChE e R.AChE de maneira semelhante, mas mostraram maior inibição sobre R.AChE. O óleo de E. globulus inibiu a AChE nativa, mas sem diferença entre a S.AChE e a R.AChE; no entanto, 71% de inibição para rBmAChE1 foi observada. O óleo de Mentha piperita também inibiu S.AChE e R.AChE, mas houve inibição significativa apenas nas concentrações mais altas testadas. O óleo de Cymbopogon winterianus não inibiu a AChE. Estudos adicionais são necessários com os óleos das duas espécies de Citrus que inibiram a R.AchE, devido ao problema de R. microplus resistente aos organofosforados ter como alvo AChE. O óleo de C. winterianus pode ser usado contra populações de R. microplus, que são resistentes a organofosforados, porque suas propriedades acaricidas agem por mecanismos diferentes.

Acaricidal potential of volatile oils from Croton species on Rhipicephalus microplus

ABSTRACT The objective of this study was to evaluate the acaricidal activity of the volatile oils of three species of Croton, Euphorbiaceae, against the cattle tick Rhipicephalus microplus. The volatile oils were obtained by hydrodistillation, analyzed by GC-MS and GC-FID and their acaricidal activity was evaluated by the larval packet test and adult immersion test. The volatile oils from Croton conduplicatus Kunth, Croton pulegiodorus Baill., and two different collections of Croton grewioides Baill. (CG1 and CG2) showed eucalyptol (24.09%), p-cymene (23.13%) and methyl chavicol (83.59% and 95.38%) as the major compounds, respectively. All the volatile oils tested in this study showed efficacy against larvae and engorged females of Rhipicephalus microplus. Therefore, Croton pulegiodorus volatile oil is promising for a potential acaricidal formulation because of the best activity against both stages of the cattle tick.

Biocidal potential of Eugenia pyriformis essential oil in the control of Rhipicephalus (Boophilus) microplus in the free-living cycle / Potencial biocida do óleo essencial de Eugenia pyriformis Cambess no controle de Rhipicephalus (Boophilus) microplus no ciclo de vida livre

Brazil has one of the largest commercial cattle herds in the world, which naturally coexist with an enormous number of parasitic species. Southern cattle tick, Rhipicephalus (Boophilus) microplus, is among these species, interfering with animal productivity and causing losses to the beef and dairy cattle sector. The use of chemical acaricides in the control of this mite has resulted in the emergence of resistant populations. In this sense, alternative control measures using plants as sources of botanical acaricides have shown to be effective. Eugenia pyriformis Cambess is a Brazilian plant with antioxidant and antimicrobial activity; however, there are no reports on its acaricidal activity in the literature. The present study aimed to evaluate the acaricidal and larvicidal potential of E. pyriformis leaf essential oil (EO) on southern cattle tick at different stages of the reproductive cycle. E. pyriformis leaves were collected and dried, and had their EO extracted by hydrodistillation (3h) using a modified Clevenger apparatus. Chemical analysis was performed by gas chromatography coupled with mass spectrometry (GC/MS), and 32 compounds belonging to the sesquiterpene class were identified: hydrocarbons (17.98%) and oxygenated forms (81.96%), with spathulenol (43.65%) and caryophyllene oxide (12.17%) as the most common. The EO was evaluated by the Adult Immersion Test at the concentrations (500.00 to 3.12mg/mL) in which the following parameters were measured: mortality of females (%), hatchability of eggs (%), and product efficiency (%). Larvae were assessed by the Larval Packet Test at concentrations ranging from 25.00 to 0.00004mg/mL. Lethal concentrations (LC) required for killing 50 and 99.9% of adult females and larvae were determined using Probit analysis. LC50 and LC99.9 of EO were 0.06 and 24.60mg/mL and 1,208.80 and 2,538mg/mL for larvae and adult females, respectively. Action of the EO in the free-living cycle of R. (B.) microplus larvae was another parameter assessed. To this end, the larvae were deposited in pots containing Brachiaria decumbens and, after migration to the leaf apex, a solution containing LC99.9 (24.60mg/mL) of the EO was sprayed. After 24h, 72.25% of the larvae had died, indicating stability of the EO when subjected to uncontrolled temperature and humidity conditions. The mechanism of action through which the EO killed the larvae and adult females was investigated by the Bioautographic Method, which showed inhibition of 3.15mg/mL of the EO on the acetylcholinesterase (AChE) enzyme. The results found in the present experiment indicate that E. pyriformis essential oil is an alternative in the control of southern cattle tick in the larval (parasitic) and free-living cycle (non-parasitic) stages under field conditions.(AU)

O Brasil dispõe de um dos maiores rebanhos bovinos comerciais do mundo, sendo natural que junto a esse rebanho, coexista uma enorme quantidade de espécies parasitárias; dentre estes o carrapato Rhipicephalus (Boophilus) microplus que interfere na produtividade animal, causando prejuízos à pecuária de corte e leite. A utilização de acaricidas químicos no controle deste ácaro tem causado o surgimento de populações resistentes e neste sentido, controles alternativos utilizando plantas como fontes de acaricidas botânicos têm se mostrado eficazes. Eugenia pyriformis Cambess é uma planta brasileira com atividades antioxidante e antimicrobiana, entretanto não há relatos da atividade acaricida. O objetivo do presente estudo consistiu na avaliação do potencial acaricida e larvicida do óleo essencial das folhas de E. pyriformis sobre o carrapato bovino nos diferentes estágios do ciclo reprodutivo. As folhas foram coletadas, secas e o OE extraído por hidrodestilação (3 horas) em aparelho Clevenger modificado. A análise química foi realizada por cromatografia gasosa acoplada à espectrometria de massas (CG/EM) sendo identificados 32 compostos, pertencentes à classe sesquiterpenos: hidrocarbonetos (17.98%) e oxigenados (81.96%); tendo como majoritários o spathulenol (43,65%) e caryophylene oxide (12,17%). O OE foi avaliado pelo teste de imersão de adultos nas concentrações (500,00 a 3,12mg/mL) onde foram mensurados os parâmetros: mortalidade das fêmeas (%), eclodibilidade dos ovos (%) e eficiência do produto (%). As larvas foram avaliadas pelo teste de imersão larval (Larval Packet Test) nas concentrações que variaram de 25,00 a 0,00004mg/mL. Foram determinadas as concentrações letais (CLs) necessárias para matar 50 e 99,9% das fêmeas adultas e das larvas utilizando a análise de Probitos. As CL50 e CL99,9 do OE foram (0,06 e 24,60mg/mL) para as larvas e (1.208,80 e 2.538mg/mL) para as fêmeas adultas, respectivamente. Outro parâmetro avaliado em nossa pesquisa foi mensurar a ação do OE no ciclo de vida livre das larvas de R.(B.) microplus; onde as larvas foram depositadas em vasos com Brachiaria decumbens e após migração destas para o ápice das folhas, foi aspergido solução contendo a CL99,9 (24,60mg/mL) do OE. Após 24 horas, 72,25% das larvas morreram indicando que houve estabilidade do OE quando submetido a condições de temperatura e umidade não controladas. O mecanismo de ação pelo qual o OE matou as larvas e fêmeas adultas foi investigado pelo método bioautográfico, indicando uma inibição de 3,15mg/mL do óleo essencial sobre a enzima acetilcolinesterase (AChE). Os resultados encontrados no presente experimento indicaram que o óleo essencial de E. pyriformis é uma alternativa no controle do carrapato bovino no estágio larval (parasitário) e no ciclo de vida livre (estágio não parasitário) em condições de campo.(AU)

Chemical composition and acaricidal activity of Ocotea notata (Lauraceae), an endemic species from Brazil, against the cattle tick Rhipicephalus microplus / Composición química y actividad acaricida de Ocotea notata (Lauraceae), una especie endémica de Brasil, contra la garrapata del ganado Rhipicephalus microplus

Rhipicephalus microplus, is one parasites that cause severe productivity losses in the cattle industry of Brazil and shows increasing resistance to conventional pesticides. This research aims to study the chemical composition, and acaricidal activity of the essential oil from Ocotea notata leaves, a brazilian endemic species, against R. microplus. The effect on R. microplus engorged adult females was evaluated using the immersion test. The oil reduced the survival by 90% after incubation for 15 days and there was 100% reduction for posture inhibition and reproductive capacity. These results suggest that the O. notata essential oil has activity on the R. microplus.

Rhipicephalus microplus, es un parásito que causa graves pérdidas de productividad en la industria ganadera de Brasil y muestra una creciente resistencia a los pesticidas convencionales. Esta investigación tiene como objetivo estudiar la composición química y la actividad acaricida del aceite esencial de las hojas de Ocotea notata, una especie endémica brasileña, contra R. microplus. El efecto sobre las hembras adultas engordadas de R. microplus se evaluó mediante la prueba de inmersión. El aceite redujo la supervivencia en 90% después de la incubación durante 15 días y hubo una reducción del 100% para la inhibición de la postura y la capacidad reproductiva. Estos resultados sugieren que el aceite esencial de O. notata tiene actividad contra R. microplus.

Comparative Acaricidal Bioefficacy Of Spilanthes Acmella And Calotropis Procera Of Eastern Himalayan Region Against Cattle Tick

In this study, relative toxicity of Spilanthes acmella and Calotropis procera wasevaluated against adults and larvae of Rhipicephalus (Boophilus) microplus. The aerial part ofboth plants materials were collected from Eastern Himalayan Region (West Bengal) of India.Plant materials were washed, shade dried, coarsely ground, methanol extracted and dried byrotary evaporator and collected proper yield of extracts. The crude methanolic extracts werefurther fractionated using solvents (hexane, ethyl acetate, chloroform) of different polarity andfinally aqueous fraction was collected and dried. Methanolic crude extracts and their fractions(hexane, ethyl acetate, chloroform and aqueous) concentrations of both the plants weretested against the engorged adult females and cultured larvae of Rhipicephalus (Boophilus)microplus. The bioefficacy observations are shown in table 3 and mentioned LC50, LC90 andtheir related statistics. Adult and larval stages were significantly affected by the chloroformextract of both the plants selected and observed the most potent with LC50 50.22 and 13.86mg/ml of Calotropis procera and LC50 60.94 and 25.82 mg/ml of Spilanthes acmella.

In vivo effect of diflubenzuron, administered via mineral salt supplementation, against Haematobia irritans and Rhipicephalus microplus parasitizing cattle / Efeito in vivo do diflubenzuron, administrado via sal mineral, contra Haematobia irritans e Rhipicephalus microplus parasitando bovinos

Abstract This study involved two field trials with the aim of evaluating the efficacy of diflubenzuron, via mineral supplementation, against Haematobia irritans parasitizing cattle. Concomitantly with the main trial, a stall test was conducted to ascertain the effects of a different formulation with the same active ingredient against Rhipicephalus microplus, along with the action of diflubenzuron on the reproductive parameters of R. microplusfemales that had naturally detached from cattle. Against H. irritans, it was observed that the efficacy indexes fordiflubenzuron were low (≤ 31.3% or 44.6%) or null (0.0%) throughout the study. The anti- R. microplus efficacy of diflubenzuron, at weekly intervals, ranged from 0.0 to 13.7% over the entire experimental period. Null efficacy (0.0%) was registered for diflubenzuron in relation to the reproductive parameters of R. microplusfemales that had naturally detached from cattle. The different diflubenzuron formulations, administered via mineral salt supplementation, did not show satisfactory efficacy indexes against H. irritans and R. microplus parasitizing cattle, within the experimental design of the present study. In addition, this agent did not present any deleterious effects on the reproductive parameters of R. microplus females.

Resumo O objetivo deste estudo foi avaliar a eficácia do diflubenzuron, administrado via suplementação mineral, contra Haematobia irritans parasitando bovinos, em dois testes à campo. Concomitantemente, foi realizado testes em estábulo para determinar os efeitos de uma formulação diferente, com o mesmo princípio ativo, contra Rhipicephalus microplus , bem como a ação do diflubenzuron nos parâmetros reprodutivos de fêmeas de R. microplus recolhidas após desprendimento natural do hospedeiro bovino. Contra H. irritans, foi observado que foram baixos (≤ 31,3% ou 44,6%) ou nulos (0,0%) os índices de eficácia do diflubenzuron. A eficácia anti-R. microplus do diflubenzuron, observada em intervalos semanais, variaram de 0,0% a 13,7% durante todo o período experimental. Com relação aos parâmetros reprodutivos das fêmeas de R. microplus recolhidas, foi observada eficácia nula (0,0%) para o diflubenzuron. Conclui-se que as diferentes formulações administradas via sal mineral no atual estudo, contra H. irritans e R. microplus parasitando bovinos, não apresentaram eficácia satisfatória. Este agente também não mostrou efeito deletério sobre os parâmetros reprodutivos de fêmeas de R. microplus.

The dynamics of energy metabolism in the tick embryo / A dinâmica do metabolismo energético em embriões de carrapato

Abstract The cattle tick Rhipicephalus (Boophilus) microplus is an ectoparasite capable of transmitting a large number of pathogens, causing considerable losses in the cattle industry, with substantial damage to livestock. Over the years, important stages of its life cycle, such as the embryo, have been largely ignored by researchers. Tick embryogenesis has been typically described as an energy-consuming process, sustaining cell proliferation, differentiation, and growth. During the embryonic stage of arthropods, there is mobilization of metabolites of maternal origin for the development of organs and tissues of the embryo. Glycogen resynthesis in late embryogenesis is considered as an effective indicator of embryonic integrity. In the cattle tick R.(B. (B.) microplus, glycogen resynthesis is sustained by protein degradation through the gluconeogenesis pathway at the end of the embryonic period. Despite recent advancements in research on tick energy metabolism at the molecular level, the dynamics of nutrient utilization during R. (B.) microplus embryogenesis is still poorly understood. The present review aims to describe the regulatory mechanisms of carbohydrate metabolism during maternal-zygotic transition and identify possible new targets for the development of novel drugs and other control measures against R. (B.) microplus infestations.

Resumo O carrapato bovino Rhipicephalus (B.) microplus é um ectoparasita capaz de transmitir diversos patógenos, sendo responsável por grandes perdas na pecuária pelos danos causados ao gado. Atualmente, muitos estudos têm negligenciado fases importantes do ciclo de vida deste parasita, como a fase embrionária. A embriogênese é classicamente descrita como um processo que demanda um consumo de energia, possibilitando a proliferação celular, diferenciação e crescimento. Além disso, em artrópodes, o estágio da embriogênese é caracterizado pela mobilização de metabolitos de origem materna para o desenvolvimento de novos tecidos e órgãos. A ressíntese de glicogênio no final da embriogênese tem sido descrita em diversas espécies de artrópodes, sendo considerada um indicador de integridade do embrião. No caso do R. (B.) microplus a ressíntese de glicogênio é sustentada pela degradação de proteínas durante a gliconeogênese, no terço final da embriogênese. Apesar dos recentes avanços, no estudo molecular e do metabolismo energético, os mecanismos envolvidos na dinâmica da utilização de diferentes substratos energéticos durante a embriogênese do carrapato R. (B.) microplus ainda é pouco entendido. Diante deste panorama, estudos que descrevam a regulação destes mecanismos e da associação do metabolismo de carboidratos com a transição materno zigótica, pode auxiliar na busca de novos alvos para o desenvolvimento de novos acaricidas e outras intervenções para o controle infestações de R. (B.) microplus.

Analysis of Bm86 conserved epitopes: is a global vaccine against Cattle Tick Rhipicephalus microplus possible? / Análise de epítopos conservados da Bm86: é possível uma vacina global contra Carrapato-do-Boi Rhipicephalus microplus?

Abstract The cattle tick Rhipicephalus microplus causes significant economic losses in agribusiness. Control of this tick is achieved mainly through the application of chemical acaricides, often resulting in contamination of animal food products and of the environment. Another major concern associated with acaricide use is the increasing reports of resistance of this tick vector against the active ingredients of many commercial products. An alternative control method is vaccination. However, the commercially available vaccine based on a protein homologous to Bm86 exhibits variations in efficacy relative to the different geographical locations. This study aimed to identify antigenic determinants of the sequences of proteins homologous to Bm86. Phylogenetic analyses were performed to determine the extent of divergence between different populations of R. microplus to identify the sequence that could be used as a universal vaccine against the multiple geographically distinct populations of R. microplus and related tick species. Considering the extensive sequence and functional polymorphism observed among strains of R. microplus from different geographical regions, we can conclude that it may be possible to achieve effective vaccination against these cattle ticks using a single universal Bm86-based antigen.

Resumo O carrapato Rhipicephalus microplus é responsável por perdas significativas no agronegócio. O controle deste carrapato é feito principalmente por meio da aplicação de acaricidas químicos, geralmente resultando na contaminação de produtos de origem animal e do meio ambiente. Outra preocupação importante associada ao uso de acaricidas é o crescente aumento de relatos sobre a resistência deste carrapato a princípios ativos de vários produtos comerciais. Uma alternativa de controle é por meio de vacinação. Porém, a vacina comercializada contendo proteína homóloga à Bm86, apresenta variações de eficácia em relação às diferentes localizações geográficas. Este estudo buscou identificar determinantes antigênicos das sequencias de proteínas homólogas a Bm86. As análises filogenéticas foram feitas para determinar a extensão da divergência entre diferentes populações de R. microplus com o objetivo de identificar a sequência que poderia ser usada como vacina universal contra as múltiplas populações geograficamente distintas de R. microplus e espécies de carrapatos relacionados. Considerando-se a extensa sequência e o polimorfismo observados entre linhagens de R. microplus de diferentes regiões geográficas, podemos concluir que pode ser possível obter uma vacinação efetiva contra esses carrapatos bovinos utilizando um único antígeno universal baseado em Bm86.

Atividade acaricida de diferentes solventes sobre fêmeas ingurgitadas e larvas de Rhipicephalus microplus / Acaricidal activity of different solvents on engorged females and larvae of Rhipicephalus microplus

Os carrapatos causam perdas econômicas à indústria pecuária no Brasil. Dessa forma, o uso de fitoterápicos como acaricidas mostrou eficácia no controle desses parasitas. Neste estudo, foi avaliada a eficácia in vitro dos seguintes fármacos: dimetil sulfóxido (DMSO), etanol, metanol, propilenoglicol e monolaurato de sorbitan polietilenoglicol em diluições de 100%, 20%, 10%, 5%, 1% e 0,5%. O efeito tóxico destes solventes em fêmeas e larvas ingurgitadas de Rhipicephalus microplus foi analisado. O teste de biocarrapaticidograma, foi utilizado para definir a eficiência reprodutiva das teleóginas de R. microplus e a eficiência dos produtos testados. Para análise da susceptibilidade das larvas foi utilizado o teste por imersão de larvas em seringa modificado. O uso de propilenoglicol e DMSO em fêmeas ingurgitadas e o uso de DMSO, etanol, metanol e propilenoglicol em larvas, todos à concentração de 0,5%, apresentaram uma menor taxa de mortalidade, podendo ter seu uso indicado em baixas concentrações como solventes de acaricidas utilizados no controle do R. microplus.(AU)

Cattle ticks cause economic losses to the cattle industry in Brazil. The use of phytotherapics as acaricides has shown efficacy of the control of these parasites. In the present study, the in vitro efficacy of the following drugs was evaluated: dimethyl sulfoxide (DMSO), ethanol, methanol, propylene glycol and polyethylene glycol sorbitan monolaurate at dilutions 100%, 20%, 10%, 5%, 1% e 0.5%. The toxic effect of these solvents on engorged female and larvae of Rhipicephalus microplus was analyzed. The immersion test was used to define the reproductive efficiency of engorged R. microplus females and efficiency of the drugs. The immersion test larvae modified syringe was used to analyze of the susceptibility of tick larvae. Propylene glycol and DMSO was used on engorged females and DMSO, ethanol, methanol and propylene glycol, all at concentration of 0.5%, were use on larvae the, showed the lowest mortality rate; this indicate that its use at low concentrations as solvent acaricide in the control of R. microplus could be recommended.(AU)

Perfil do produtor de leite da região de Joanópolis/SP: como ele lida com o controle do carrapato Rhipicephalus microplus e de outras doenças de importância veterinária / Profile of dairy farmers of the Joanópolis/SP region, Brazil: how they deal with Rhipicephalus microplus control and other diseases of veterinary interest

Este estudo verificou o perfil do produtor de leite do município de Joanópolis, SP, situado a 115 km de São Paulo, e como esse produtor lida com o controle do carrapato e outras doenças importantes na pecuária leiteira. Quarenta produtores de leite foram entrevistados. Verificou-se que grande parte deles se enquadra em agricultura familiar: pequenas propriedades com mão-de-obra familiar. Verificou-se que 72,5% possuem outra fonte de renda além do leite; 75% produzem menos que 100 litros de leite por dia, e a maioria não é tecnificada (ordenha manual: 72,5 %; não faz escrituração zootécnica: 55%; não aduba pastos: 80%; não utiliza inseminação artificial: 87,5%). O controle do carrapato é feito sem critérios técnicos; a aplicação do carrapaticida é feita no mesmo local da ordenha; 90% não usam equipamentos de proteção individual para aplicar o carrapaticida. O gado prevalente é o mestiço Girolando (87,5%), que, por ser mais resistente ao carrapato, deve contribuir para que 57,5% dos entrevistados estejam satisfeitos com o controle do carrapato. Verificou-se que poucos produtores (apenas 12,5%) possuem assistência técnica constante. Isso pode ser a explicação para o baixo uso de tecnologias e nas falhas observadas no diagnóstico das doenças e no controle do carrapato.(AU)

This study made a detailed description of the milk producer of the municipality of Joanópolis/SP, situated 115 km from the largest city of Brazil, São Paulo, and how they deal with tick control and other important diseases for dairy farming. Forty milk producers were interviewed. It was found that most of them fit into family farms: small farms with family labor; 72.5% have another source of income in addition to the milk; 75% produce less than 100 liters of milk per day; and most of them are not technified (72.5% do manual milking; 55% do not keep zootechnical records; 80% do not fertilize the pastures; 87.5 % do not use artificial insemination). Tick control is made without technical criteria. A hundred percent of the interviewed applied the acaricide in the same place of milking; 90% do not use protective equipment to apply the acaricide. The prevalent cattle breed is the crossbred Girolando (87.5%), a more tick resistant breed. This may contribute to 57.5% that are satisfied with tick control. It was found that few producers (only 12.5%) have constant technical assistance. This may be the explanation for the low use of technologies and the failures observed in the diagnosis of diseases and the use of tick control.(AU)

Anti-inflammatory and antinociceptive activities of Rhipicephalus microplus saliva

Objective: To evaluate the antinociceptive and anti-inflammatory activities and the toxic effects of Rhipicephalus microplus saliva for elucidating the modulation mechanism between arthropod saliva and host. Methods: For saliva collection, engorged ticks were obtained from a controlled bovine infestation and collected by natural fall. The ticks were fixed and injected pilocarpine 0.2% for induction of salivation. Saliva was collected, lyophilized and stored at - 80 °C. Cytotoxic activity was assessed by the hemolysis method (25, 50, 100, 200 and 300 μ g/mL) and MTT cell viability assay (2.5, 5, 10, 20 and 40 μ g/mL) for 24, 48 and 72 h. Anti-inflammatory activity was evaluated using the method of neutrophil migration to the peritoneal cavity of mice at doses of 10, 15 and 20 mg/kg; antinociceptive activity was assessed using the acetic acid-induced writhing test, and formalin-induced paw-licking in mice at dose of 15 mg/kg. Results: Saliva did not cause erythrocytes hemolysis at any concentration tested, as well as did not decrease cell viability in the MTT assay. Saliva inhibited neutrophil migration by 87% and 73% at doses of 15 and 20 mg/kg, respectively. In the nociceptive tests, saliva presented analgesic activity of 69.96% in the abdominal writhing test, and of 84.41% in the formalin test. Conclusions: The study proves that Rhipicephalus microplus saliva has significant in vivo anti-inflammatory and antinociceptive activities. The data presented herein support the development of further studies to elucidate the active principles of Rhipicephalus microplus saliva and its mechanism of action and, in future, to develop novel anti-inflammatory and analgesic drugs.

Anti-inflammatory and antinociceptive activities of Rhipicephalus microplus saliva

Objective: To evaluate the antinociceptive and anti-inflammatory activities and the toxic effects of Rhipicephalus microplus saliva for elucidating the modulation mechanism between arthropod saliva and host. Methods: For saliva collection, engorged ticks were obtained from a controlled bovine infestation and collected by natural fall. The ticks were fixed and injected pilocarpine 0.2％for induction of salivation. Saliva was collected, lyophilized and stored at - 80 ℃. Cytotoxic activity was assessed by the hemolysis method (25, 50, 100, 200 and 300 μg/mL) and MTT cell viability assay (2.5, 5, 10, 20 and 40 μg/mL) for 24, 48 and 72 h. Anti-inflammatory activity was evaluated using the method of neutrophil migration to the peritoneal cavity of mice at doses of 10, 15 and 20 mg/kg; antinociceptive activity was assessed using the acetic acid-inducedwrithing test, and formalin-induced paw-licking in mice at dose of 15 mg/kg. Results: Saliva did not cause erythrocytes hemolysis at any concentration tested, as well as did not decrease cell viability in the MTT assay. Saliva inhibited neutrophil migration by 87％ and 73％ at doses of 15 and 20 mg/kg, respectively. In the nociceptive tests, saliva presented analgesic activity of 69.96％ in the abdominal writhing test, and of 84.41％ in the formalin test. Conclusions: The study proves that Rhipicephalus microplus saliva has significant in vivo anti-inflammatory and antinociceptive activities. The data presented herein support the development of further studies to elucidate the active principles of Rhipicephalus microplus saliva and its mechanism of action and,in future, to develop novel anti-inflammatory and analgesic drugs.

Identification and prevalence of ticks (Acari, Ixodidae) in bovines in five municipalities of the Popayán plateau (Colombia) / Identificación y prevalencia de garrapatas (Acari, Ixodidae) en bovinos en cinco municipios de la meseta de Popayán (Colombia) / Identificação e prevalência de carrapatos (Acari, Ixodidae) em bovinos em cinco municípios no planalto de Popayán (Colombia)

Abstract Background: Ticks and tick-borne diseases are one of the major problems of public and animal health worldwide. Tick infestation causes economic losses in cattle farms of the Popayán plateau (Cauca, Colombia) due to costs associated with preventive management, decreased production of milk and meat, as well as transmission of diseases such as babesiosis and anaplasmosis. Objective: To determine the type and degrees of tick infestation in cattle of the Popayán plateau and its correlation with erythrogram and blood parasites frequency. Methods: One-thousand four-hundred forty cattle were evaluated in 144 farms distributed in Popayán, Cajibio, Timbio, Morales, and Piendamó. In each farm ticks were collected, quantified, and identified from 10 bovines of 1 year of age or older regardless of sex or breed. Additionally, a blood sample was taken from five of the animals to evaluate the erythrogram and determine the presence of blood parasites. Results: Tick prevalence was 79.5%; of these, 99.6% were Rhipicephalus microplus and 0.4% were Dermacentor nitens. Most cattle (58%) presented medium and high degrees of tick infestations (11 to 50, and more than 50 ticks, respectively) with a weak relationship between the degree of tick infestation and red blood cell counts, and no relationship between the degree of tick infestation and the presence of blood parasites. Conclusion: Cattle herds in Popayán plateau have a medium to high degree of tick infestation with R. microplus.

Resumen Antecedentes: Las garrapatas y enfermedades transmitidas por estas son uno de los grandes problemas de salud pública y veterinaria en el mundo. En la meseta de Popayán (Cauca, Colombia) la infestación por garrapatas causa pérdidas económicas en las explotaciones ganaderas debido a mayores costos por manejo preventivo, disminución en la producción de leche, carne y pieles, y transmisión de enfermedades como babesiosis y anaplasmosis. Objetivo: Determinar el tipo de garrapatas y grado de infestación en bovinos de la meseta de Popayán y correlacionarlo con el eritrograma y presencia de hemoparásitos. Métodos: Se evaluaron 1.440 bovinos en 144 fincas de los municipios de Popayán, Cajibio, Timbio, Morales y Piendamó. En cada finca se colectaron, cuantificaron, e identificaron las garrapatas de 10 bovinos mayores de 1 año, independientemente de sexo o raza, y a cinco de ellos se les tomó muestra de sangre para realizar eritrograma y determinar presencia de hemoparásitos. Resultados: La prevalencia de garrapatas fue 79,5%; de ellas, 99,6% eran Rhipicephalus microplus y 0,4% Dermancentor nitens. La mayoría de los bovinos (58%) presentaron infestación media y alta (11 a 50, y más de 50 garrapatas, respectivamente). Se encontró una baja relación entre grado de infestación y nivel de glóbulos rojos, y no se encontró relación entre grado de infestación y presencia de hemoparásitos. Conclusión: Las ganaderías de la meseta de Popayán presentan un grado medio-alto de infestación por garrapatas, principalmente por R. microplus.

Resumo Antecedentes: Os carrapatos e as doenças transmitidas por eles são um dos principais problemas de saúde pública e animal em todo o mundo. No planalto de Popayán, departamento de Cauca (Colômbia), a infestação por carrapato é uma importante causa de perdas econômicas nas explorações pecuárias devido aos custos de manejo preventivo, diminuição da produção de leite, carne e peles, além da transmissão de doenças como babesiose e anaplasmose. Objetivo: Determinar o tipo de carrapato e o grau de infestação em bovinos no planalto de Popayán e correlacioná-los com os achados no eritrograma e a presença de hemoparasitas. Métodos: Foram avaliados 1.440 animais em 144 fazendas distribuídas nos municípios de Popayán, Cajibio, Timbio, Morales e Piendamó. Em cada propriedade foram coletados, quantificados e identificados carrapatos de 10 bovinos com mais de 1 ano de idade independentemente do sexo ou raça; de cinco deles foram colatadas amostras de sangue para realização de eritrograma e determinação da presença de hemoparasitas. Resultados: A prevalência de carrapatos foi de 79,5%; 99,6% dos carrapatos identificados eram da espécie Rhipicephalus microplus e 0,4% Dermancentor nitens. A maioria dos animais (58%) apresentou média e alta infestação (11 a 50 e mais do 50, respectivamente). Foi encontrada uma baixa relação entre o grau de infestação por carrapatos e número de células vermelhas no sangue, e não foi encontrada nenhuma relação entre grau de infestação por carrapatos e a presença de hemoparasitas. Conclusaõ: Os bovinos no planalto de Popayán apresentam um grau de infestação por carrapatos médio-alto, principalmente por R. microplus.

Resistencia in vitro de la garrapata Rhipicephalus microplus a organofosforados, piretroides y amitraz en el Departamento de Boyacá, Colombia / In vitro Resistance of Rhipicephalus microplus ticks to Organophosphates, Pyrethroids and Amitraz in Boyacá Department, Colombia

El presente estudio evaluó la resistencia in vitro de la garrapata Rhipicephalus microplus a organofosforados (OF), piretroides sintéticos (PS) y amitraz (AM). Las garrapatas adultas fueron recolectadas en Boyacá, Colombia y sometidas a la prueba de inmersión para evaluar la eficacia de los fármacos, el efecto sobre la ovoposición y el porcentaje de eclosión larvaria. Se utilizó un diseño experimental completamente al azar con cinco grupos y tres repeticiones por tratamiento, con 10 garrapatas por repetición. Los resultados demostraron tasas de mortalidad a las moléculas evaluadas, encontrando 43, 56, 60 y 96% de mortalidad para el grupo control, PS, AM y OF, respectivamente, al día 21 del experimento. La inhibición de la ovoposición fue de 13,4% para el grupo control, 44,6% para AM, 45,5% para PS y 96% para OF. El porcentaje de eclosión de huevos fue de 88% para el grupo control, 16% para AM, 14% para PS y 4% para OF. El presente estudio in vitro representa el primer diagnóstico en el departamento de Boyacá, Colombia.

The present investigation evaluated the in vitro resistance of the Rhipicephalus microplus tick, to organophosphates (OP), synthetic pyretroids (SP), and amitraz. Adult ticks were collected in the Department of Boyacá, Colombia, and subjected to the immersion test, to assess the efficacy of drugs, their effect on oviposition, and the percentage of larvae eclosion. A completely randomized experimental design was used, with 5 groups and 3 replicates per group, with 10 ticks per replicate. The results showed that the mortality rates in terms of percentage (%) of the assessed molecules were: 43 for the control group; 56 for SP; 60 for AM, and 96 for OP, respectively, at day 21 of the study. The inhibition of oviposition was: 13.4% for the control group; 44.6% for AM; 45.5% for SP; and 96% for OP. The present in vitro study represents the first diagnostic of resistance in the Department of Boyacá, Colombia.

Efecto de los extractos vegetales de Jatropha curcas y Anonna muricata sobre teleoginas de la garrapata común del ganado Ripichephalus (Boophilus) microplus bajo condiciones de laboratorio / Effect of plant extracts of jatropha curcas and Anonna muricata on engorged females of common cattle tick Ripichephalus (Boophilus) microplus under laboratory conditions / Efeito de extractos de plantas de Jatropha curcas e Anonna muricata em teleogines do carrapato gado comum Ripichephalus (Boophilus) microplus sob condições de laboratório

Resumen La garrapata común (Rhipicephalus (B.) microplus) del ganado es considerada el ectoparásito más importante en la ganadería. El uso repetitivo y tradicional de acaricidas comerciales se ha convertido en un serio problema en cuanto a la resistencia adquirida por esta garrapata. Por esta razón, el control biológico ha surgido como una alternativa prometedora en el control de este ectoparásito. En este estudio se evalúa el efecto de los extractos vegetales de dos plantas, J. curcas y A. muricata, sobre el índice de producción de huevos y la eficiencia reproductiva de R (B.) microplus bajo condiciones de laboratorio. Cada extracto fue evaluado a cinco concentraciones (entre 0.1 y 5%), usando controles negativo y positivo para su comparación. Ambas plantas mostraron actividad biológica, sin embargo, A. muricata tuvo un efecto mayor comparado con J. curcas, inclusive a concentraciones bajas (0,5 y 1 %). Por el contrario, J. curcas mostró solo un efecto moderado en concentraciones altas (5%). En conclusión, los resultados obtenidos en laboratorio indican que los extractos de A. muricata son promisorios para controlar la garrapata común del ganado.

Abstract Rhipicephalus (B.) microplus or common cattle tick is considered the most important ectoparasite of livestock. Traditional and repetitive control of this tick through the use of conventional products has become a serious problem regarding tick's resistance. For this reason, biological control has emerged as a very promising alternative to control this tick. In the present study, an experiment was designed to assess the effect of plant extracts of J. curcas y A. muricata on Production eggs Index (IPH) and estimated reproduction (ER) of R (B) microplus under laboratory conditions. Each plant extract was assessed in five different concentrations (between 0.1 and 5%); a positive and negative control was used for comparison. Both plants showed biological activity, however, A. muricata showed significantly effect on engorged females of the cattle tick compared with J. curcas, even at lower concentrations (0.5, and 1 %). In conclusion, the results obtained indicate that A. muricata's seed extracts are promissory to biocontrol the common cattle tick under laboratory conditions.

Resumo O carrapato comum (Rhipicephalus (B.) microplus) do gado é considerado o ectoparasita mais importante da pecuária. O uso repetitivo e tradicional de inseticidas comerciais se converteu em um sério problema quanto a resisitência adquirida por esse carrapato. Por essa razão, o controle biológico surgiu como uma alternativa promissora no controle deste ectoparasita. Esse estudo avalia o efeito dos extratos vegetais das plantas,J. curcas e A. muricata,sobre o índice de produção de ovos e a eficiência reprodutiva deR (B.) microplussegundo condições de laboratório. Cada extrato foi avaliado em 5 concentrações (entre 0,1 e 5%), usando controles negativo e positivo para sua comparação. Ambas as plantas mostraram atividade biológica, porém,A. muricatateve um efeito maior comparado comJ. curcas,inclusive as concentrações baixas (0,5 y 1 %). Pelo contrário,J. curcasmostrou só um efeito moderado nas concentrações altas (5%). Em conclusão, os resultados obtidos no laboratório indicam que os extratos deA. muricatasão promissores para controlar o carrapato comum do gado.