Influence of agricultural extension activities on tick control among cattle on family dairy farms in the southeast Brazil (original) (raw)
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Veterinary medicine international, 2011
The adult immersion test (AIT) was used to evaluate the efficacy of acaricide molecules used for control of Rhipicephalus microplus on 106 populations collected in five municipalities in the state of Rondônia in the Brazilian South Occidental Amazon region. The analysis of the data showed that the acaricide formulations had different efficacies on the tick populations surveyed. The synthetic pyrethroids (SPs) acaricides were the least effective (48.35-76.84%), followed by SP + organophosphate (OP) associations (68.91-81.47%) and amidine (51.35-100%). For the macrocyclic lactones (MLs), the milbemycin (94.84-100%) was the most effective, followed by spinosad (93.21-100%) and the avermectins (81.34-100%). The phenylpyrazole (PZ) group had similar efficacy (99.90%) to the MLs. Therefore, SP acaricides, including associations with OP, and formulations based on amidine presented low in vitro efficacy to control the R. microplus populations surveyed.
Environmental Health Insights, 2015
Two distant Antioquian cattle farms where systemic and topical acaricides had previously failed to control infestations by Rhipicephalus (Boophilus) microplus were studied. An initial in vivo study was conducted using single subcutaneous injections with a long-acting formulation of ivermectin (630 µg/kg). Injections were made at 3-month intervals on animals at each farm to evaluate the therapeutic and persistent efficacy of ivermectin against citronella (208 ppm + 10 ppm, respectively) was shown to be less efficacious than the name-brand amitraz product. Products containing the organophosphate chlorpyrifos or trichlorfon exhibited intermediate efficacies of approximately 60% at the Tarso farm. We conclude that at these two locations, there is a high degree of resistance to many of the acaricides available in Colombia and confirm suspicions that ivermectin is no longer able to eliminate tick infestations.
Regional Study of Action in Vitro of Commercial Acaricides on the Cattle Tick
2019
To evaluate the effect of commercial acaricides for the control of Rhipicephalus (Boophilus) microplus in the region of Uberaba, Minas Gerais, engorged female cattle ticks were collected from five properties. These samples were immersed in previously prepared solutions containing five acaricide treatments and one control, as follows: T1, control (distilled water); T2, Amitraz (12.5%); T3, Cypermethrin (15%); T4, Deltamethrin (2.5%); T5, Cypermethrin (15%) + Chlorpyrifos (25%) + Citronellal (1%); and T6, Dichlorvos (60%) + Chlorpyrifos (20%). Ticks were then dried on absorbent paper, taped onto Petri dishes, and placed in an incubator at 27.0°C and humidity greater than 80%. After 20 days of fixation, the eggs of each group were collected, weighed, and placed in modified plastic syringes and again kept in an incubator until the larvae hatched. A greater reduction in egg mass was observed with Amitraz (12.5%) and the combination of Cypermethrin (15%) + Chlorpyrifos (25%) + Citronellal...
Veterinary Parasitology: Regional Studies and Reports
The objective of this work was to evaluate the efficacy of two cypermethrin-and chlorpyrifos-based acaricides in controlling Rhipicephalus microplus in a naturally infested bovine herd and in in vitro tests, as well as to monitor the animals for tick fever. Male bovines in the rearing phase were used, with 30 Brangus and 30 Nellore animals naturally infested. The groups were composed as follows: 15 Nellore treated, 15 Nellore control, 15 Brangus treated and 15 Brangus control. Every 18 days, the animals were monitored for tick count, acaricide treatment, weight, blood pack cell volume, and clinical signs. For in vitro tests, the larval packet test, adult immersion test and DNA amplification for tick fever diagnosis were performed. In the first animal treatment period, product 1 (cypermethrin, 15 g + chlorpyrifos, 25 g + citronellal, 1 g) was used; in the second period, product 2 (cypermethrin, 15 g + chlorpyrifos, 30 g + fenthion, 15 g) was used. In Brangus animals, the mean efficacy was 35.1% and 95.8% in the first and second periods, respectively, for the same animals. For Nellore animals, the efficacy in periods one and two was 51% and 97.1%, respectively. The in vitro results showed efficacy above 95% for the two challenged acaricides. The Brangus animals showed a high production of ticks associated with the presence of tick fever agents, which could generate risks for the disease's enzootic stability
Acaricide resistance in cattle ticks and approaches to its management: The state of play
Cattle ticks are an important constraint on livestock production, particularly in tropical and subtropical areas. Use of synthetic acaricides is the primary method of tick control; therefore, it would be imperative to develop strategies to preserve the efficacy of existing acaricides. This paper summarizes the status of acaricide resistance in cattle ticks from different parts of the world and reviews modes of action of currently used acaricides, mechanism of resistance development, contributory factors for the development and spread of resistance, management of resistant strains and strategies to prolong the effect of the available acaricides. Use of vaccines, synthetic and botanical acaricides and educating farmers about recommended tick control practices are discussed, along with the integration of currently available options for the management of drug resistance and, ultimately, the control of cattle ticks.
PLOS ONE, 2017
Rhipicephalus microplus is widely distributed in tropical and subtropical areas of the world where livestock is a principal activity with great veterinary and economic importance. In Ecuador, this hematophagous ectoparasite has been observed between 0 and 2600 masl. One of the main tick control measures is the use of acaricides, which have been indiscriminately used worldwide and in Ecuador. In this country, no studies on acaricide resistance in Rhipicephalus microplus have been published. The current study aims to characterise the level of resistance of R. microplus against three main acaricides commonly used in Ecuador i.e. amitraz, alpha-cypermethrin and ivermectin to determine the level and pattern of doseresponses for R. microplus in 12 field populations (farms). The level of acaricide resistance was evaluated using three different bioassays: adult immersion test (AIT), larval package test (LPT) and larval immersion test (LIT), as recommended by the FAO. The predictive dose-responses were analysed by binomial logistics regression of the larval survival rate (resistance). In general, we found resistance of 67% for amitraz; 50% for alpha-cypermethrin and from 25 to 42% for ivermectin in the twelve field populations analysed. Resistance levels were studied in larval and adult bioassays, respectively, which were slightly modified for this study. For larval bioassays based on corrected mortality i.e. high (above 51%), medium (21-50%) and low (11-20%) resistance, percentages less than 10% were considered as susceptible. For the adult test, two resistance levels were used i.e. high (more than 76%) and medium (51 to 75%) resistance. Percentages lower than 50% were considered as susceptible. In this context, for larval bioassays, amitraz showed 21%, 38% and 8% for high, medium and low resistance, respectively. Alpha-cypermethrin presented 8%, 4 and 38% for high, medium and low resistance, respectively. Ivermectin presented 8%, 25% and 8% for high, medium and low resistance, respectively. For adult tests with amitraz 50% and 17% of the field populations showed average and high resistance, with evidences of average resistance to alpha-cypermethrin in 50% of the samples and average resistance against PLOS ONE |
International Journal of Biological and Chemical Sciences
Cattle tick Rhipicephalus microplus has become a common problem for cattle herders in Côte d’Ivoire after its discovery there in the early 2000s, despite the availability of a large range of acaricide products. The objective of this study was to assess the resistance of the cattle tick R. microplus to alphacypermethrin, deltamethrin and amitraz, and to provide information to advice farmers of acaricide products choice in Côte d’Ivoire. A cross-sectional survey was conducted in September 2016 on nine farms where resistance to acaricides was suspected. Engorged R. microplus females were sampled and transported to the International Centre for Research and Development on Subhumid Livestock Production (CIRDES) in Burkina Faso. The FAO larval packet test method (adapted by CIRDES) was applied to assess the resistance-susceptibility level of the R. microplus tick populations to three common acaricidal molecules (alphacypermethrin, deltamethrin and amitraz) in Côte d’Ivoire. The results sho...
Insecticides [Working Title], 2021
Resistance to insecticides is one of the major obstacles to the control of agricultural pests, as well as species important to human and veterinary health. The World Health Organization has called insecticide resistance “the great little obstacle against vector-borne diseases”. Rhipicephalus (Boophilus) microplus is one of the most important vector, transmitting diseases to cattle such as anaplasmosis and babesiosis. These diseases cause great economic losses that significantly increased because of the appearance of tick populations resistant to acaricides, as a result of the intensive use of pesticides. Resistance to ixodicides in Latin America is a growing problem, since control of disease-transmitting ticks, depends heavily on the use of pesticides. In Mexico, the resistance of R. microplus to organophosphate compounds, pyrethroids, and recently amidines, has been detected in some areas, affected by multiple acaricide resistance to the three families of ixodicides. The cattle tic...
Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology: Orgao Oficial do Colegio Brasileiro de Parasitologia Veterinaria
This study evaluates milk producers' knowledge regarding cattle ticks and practices for controlling them. Ninety-three dairymen in Minas Gerais were interviewed. These producers had no information regarding acaricide efficiency tests. To analyze the information, open responses were categorized through "content analysis", and descriptive analysis consisting of extracting the profile highlighted by the highest frequencies. The association between schooling level and knowledge was tested by means of chi-square trend tests. It was observed that 92.3% had no knowledge of the nonparasitic period. For 96.4%, what determined the time to apply treatment was the degree of tick infestation; 93.3% used spray guns to apply the acaricide. In seeking to cross-correlate the biological and control variables with education, cooperative action, length of experience and herd size, it was found that there was a linear association between schooling level and implementation of acaricide solu...
Ecology and Control of Vector-borne Diseases
Rhipicephalus microplus, the cattle tick, causes enormous losses for producers of beef, dairy and leather. Currently acaricides are the only method of treatment available to producers, but they are losing their efficacy due to alarming rates of resistance in tick populations, with new mechanisms of resistance being described regularly. Producers must invest in testing the level and type of resistance in field populations in order to select an effective treatment for subsequent seasons, to hinder spread of resistant ticks and achieve the most cost-effective strategy. Besides the levels of resistance to acaricides currently seen, these chemicals also impact greatly on the environment and on the quality of animal products consumed downstream in the food chain. In view of these problems, new and sustainable technologies to control infestations of ticks in cattle (and other commonly used meat-providing hosts) are urgently needed. Feasible alternatives consist of natural products from botanical extracts that kill ticks and/or have repellent properties, capable of modify the off-and on-host ecosystems of the tick. Modifications of the off-host ecosystem of the R. microplus tick consists of increasing its chances for desiccation, predation and/or infection of adults, eggs and larvae to reduce fecundity and hampering the host-seeking capacities of larvae and their vectorial capacity. The choice of a production system, including choice of pasture, and biological control agents can assist in achieving this goal. Modifications of the on-host ecology require that the bovine host mounts efficacious reactions to expel or repel ticks and/or hamper their blood-feeding and vectorial capacity; these responses can be induced by genetic selection, vaccination and/or interventions in the host's and in the tick's microbiota. Control strategies must consider endemic stability for maintaining adequate levels of immunity against tick-borne pathogens; they also require that producers understand their mechanisms of action in affecting tick biology in order to maintain adequate compliance and thus success.