Acaricide Treatments Research Articles

The influence of anthropogenic factors on the morphological features of the leaf apparatus of the balsamic poplar (Populus balsamifera L.)

The use of a promising culture of balsamic poplar in the 1950-1970s post-war years in the landscaping of Siberian cities became widespread in squares, parks, lawns along the road network and in urban forests. At the time of the creation of such landscaping facilities, the conditions of their growth did not have significant differences. To date, with the development of motorization, the use of reagents for the maintenance of the road network and the conduct of acaricide treatments in squares and parks, a significant difference has formed in the growing conditions of balsamic poplar crops. Biomonitoring of the state of the environment was carried out at three fundamentally different sites in Novosibirsk. Evaluation of the fluctuating asymmetry of balsamic poplar leaves showed that ordinary plantings along the road network are characterized by a high deviation from the stability of development. Forest crops of balsamic poplar in urban forests are characterized by the presence of deviations from the stability of development. The best indicators were obtained for balsamic poplar plantings in landscape groups in the park - the presence of a weak deviation from the stability of development. The best indicators were obtained for balsamic poplar plantings in landscape groups in the park - the presence of a violation of the stability of development. To date, 50-70-year-old balsamic poplar crops grown on the territory of the megalopolis are characterized by varying degrees of disturbance or deviation from the stability of development. They can be arranged according to the stability reduction scale in the following order: landscape groups in the park, forest crops in urban forests and ordinary planting on lawns along the road network.

Acaricidal efficacy evaluation of amitraz and diazinon against Amblyomma variegatum tick species in Waghimra zone, northern Ethiopia.

Ticks pose a substantial economic burden associated with production loss and treatment costs globally. Ethiopia has tremendous livestock resources, but its productivity is hindered by various animal health challenges in which ticks are the top priority, with a limited response to acaricidal treatments. Hence, we designed an acaricidal efficacy trial for the top commercially available Chemicals (amitraz and diazinon) to examine their efficacy against the widely distributed tick species (Amblyoma variegatum). Ticks were collected from animals admitted to veterinary clinics with no history of treatment with acaricides. Adult Immersion Technique (AIT) was employed to detect acaricidal resistance, and the mean percent control and antiparasitic efficacy were used to estimate tick susceptibility with a completely randomized laboratory-based trial (CRT). The mean weights of eggs laid by ticks subjected to amitraz and diazinon indicated that amitraz had a better egg-laying-inhibition effect than diazinon. The mean control percentages of amitraz and diazinon were 92.8±5.6% and 69.7±3.1%, respectively, with a highly significant difference (P-value=0.00). The antiparasitic efficacy of the two drugs was 57.5±0.96 and 37.5%±0.96 for amitraz and diazinon, respectively, which revealed that amitraz was statistically better than diazinon in killing adult ticks (P-value =0.026). In general, ticks treated with diazinon showed evidence of resistance development, and amitraz is relatively the most effective acaricide; we recommend its use in the study area and other locations with similar settings.

An economic evaluation of cattle tick acaricide-resistances and the financial losses in subtropical dairy farms of Ecuador: A farm system approach.

Estimates of economic losses in cattle due to tick infestations in subtropical areas are limited, such as in Ecuador. Ticks affect animal production and health, but those direct effects are difficult to estimate since financial exercises carried out in farms consider both costs of the inputs and revenues. This study aims to quantify the costs of inputs involved in milk production and to know the role of acaricide treatment in the production costs on dairy farms in subtropical zones using a farming system approach. Regression and classification trees were used to study the relationship between tick control, acaricide resistance and the presence of high level of tick infestation in the farm system. Even though there was no significant direct association between high levels of tick infestation and the presence of acaricide resistance in ticks, a more complex structure for resistances operates in the manifestation of high tick infestation involving levels of farm technology and no acaricide resistance. Farms with higher levels of technology allocate a lower percentage of sanitary expenses to control ticks (13.41%) in comparison to semi-technified (23.97%) and non-technified farms (32.49%). Likewise, more technified and bigger herds have a lower annual expenditure on acaricide treatment (1.30% of the production budget equivalent to 8.46 USD per animal) compared to non-technified farms where it can represent more than 2.74% of the production budget and where the absence of cypermethrin resistance increases the treatment cost to 19.50 USS per animal annually. These results can motivate the development of information campaigns and control programmes targeted to the reality of small and medium farms that are the most affected in terms of the money they invest in controlling ticks.

Experimental oral delivery of the systemic acaricide moxidectin to free-ranging white-tailed deer (Artiodactyla: Cervidae) parasitized by Amblyomma americanum (Ixodida: Ixodidae).

Orally delivered, host-targeted, systemic acaricide treatment has potential to be an effective areawide tick abatement strategy. Past efforts using ivermectin for livestock were reported effective at controlling both Amblyomma americanum (L.) and Ixodes scapularis Say on Odocoileus virginianus (Zimmermann). However, the labeled 48-day withdrawal period for human consumption largely prevented utilization of this strategy targeting I. scapularis in autumn, when peak adult host-seeking activity coincides with regulated white-tailed deer hunting seasons. The modern-day compound moxidectin is the active ingredient in the pour-on formulation Cydectin (5 mg moxidectin/ml; Bayer Healthcare LLC), with a labeled 0-day withdrawal period for human consumption of treated cattle. We sought to re-examine the systemic acaricide approach for tick management by determining if we could successfully deliver Cydectin to free-ranging white-tailed deer. Over 2 yr in late spring/early summer, coinciding with adult and nymphal A. americanum activity, we fed Cydectin-coated corn to free-ranging white-tailed deer in coastal Connecticut. Through serum analysis, we documented moxidectin levels at or above those previously reported effective for control of ectoparasites (5-8 ppb for moxidectin and ivermectin) in 24 of 29 white-tailed deer captured (83%) while exposed to treated corn. While we did not document differences in burdens of parasitizing A. americanum based on moxidectin sera levels, we did document fewer engorged specimens on deer with increased sera levels. The systemic use of moxidectin for tick management in critical reproductive hosts has the potential to be effective in an areawide capacity while also permitting human consumption of treated venison.

Does Experimental Reduction of Blacklegged Tick (Ixodes scapularis) Abundance Reduce Lyme Disease Incidence?

Controlling the abundance of blacklegged ticks is considered the foundation for the prevention of human exposure to pathogens transmitted by these vectors in eastern North America. The use of broadcast or host-targeted acaricides is generally found to be effective at reducing the local abundance of ticks. However, studies that incorporate randomization, placebo controls, and masking, i.e., "blinding", generally find lower efficacy. The few studies that include measurements of human-tick encounters and cases of tickborne disease have not shown impacts of acaricidal treatments. We compile literature on relevant studies from northeastern North America to address possible causes for discrepancies in study outcomes and suggest possible mechanisms that could underlie the diminished efficacy of tick control in reducing cases of tickborne disease in people.

Orally delivered fipronil-laced bait reduces juvenile blacklegged tick (Ixodes scapularis) burdens on wild white-footed mice (Peromyscus leucopus)

While the topical acaricidal treatment of rodent pathogen reservoirs has been readily explored over the past several decades, oral systemic acaricidal treatment is only recently gaining traction as an alternative approach to the management of ticks and tick-borne pathogens. Recent laboratory tests have shown promise in the effectiveness of this systemic strategy against the blacklegged tick (Ixodes scapularis) and a Canadian field evaluation was recently published, but no recent field data from the United States yet exist. With this research, we sought to field deploy a commercially available fipronil-laced bait (Kaput® Flea Control Bait, Scimetrics LLC., Wellington, CO, USA; 0.005% fipronil; Environmental Protection Agency Reg. No. 72500-28), in an alternate use targeting white-footed mice (Peromyscus leucopus) to determine bait acceptance and potential impacts to juvenile I. scapularis burdens. Bait was readily accepted by wild P. leucopus and other rodent reservoirs. An ad libitum distribution strategy as well as placing smaller volumes of fipronil-laced bait within individual Sherman traps both resulted in significant reductions (57-94%) in juvenile I. scapularis burdens as compared to control over two years. The oral delivery of systemic acaricides shows promise in reduction of I. scapularis burdens on P. leucopus and should be further explored to determine effectiveness on host-seeking tick abundances, associated pathogen infection, and potentially incorporated into integrated tick management programs.

Transcriptome Profiling of Rhipicephalus annulatus Reveals Differential Gene Expression of Metabolic Detoxifying Enzymes in Response to Acaricide Treatment.

Ticks are hematophagous ectoparasites of economic consequence by virtue of being carriers of infectious diseases that affect livestock and other sectors of the agricultural industry. A widely prevalent tick species, Rhipicephalus (Boophilus) annulatus, has been recognized as a prime vector of tick-borne diseases in South Indian regions. Over time, the use of chemical acaricides for tick control has promoted the evolution of resistance to these widely used compounds through metabolic detoxification. Identifying the genes related to this detoxification is extremely important, as it could help detect valid insecticide targets and develop novel strategies for effective insect control. We performed an RNA-sequencing analysis of acaricide-treated and untreated R. (B.) annulatus and mapped the detoxification genes expressed due to acaricide exposure. Our results provided high-quality RNA-sequenced data of untreated and amitraz-treated R. (B.) annulatus, and then the data were assembled into contigs and clustered into 50,591 and 71,711 uni-gene sequences, respectively. The expression levels of the detoxification genes across different developmental stages of R. (B.) annulatu identified 16,635 transcripts as upregulated and 15,539 transcripts as downregulated. The annotations of the differentially expressed genes (DEGs) revealed the significant expression of 70 detoxification genes in response to the amitraz treatment. The qRT-PCR revealed significant differences in the gene expression levels across different life stages of R. (B.) annulatus.

Bacteriocarriage of ixodid mites on the Trans-Baikal Territory

The results of a microbiological study of sexually mature ixodid mites of the genus Dermacentor collected in the rural areas of the Trans-Baikal Territory are presented. Microbiological examination of 152 ixodid mites was carried out. Four microbial cultures of different species were identified: Listeria monocytogenes, E. coli, Salmonella typhi, Clostridium botulinum. The presence of bacteria associations of different species groups in the mite body was noted: in 32 individuals - L. monocytogenes, E. coli, S. typhi, in 56 - C. botulinum, E. coli, S. typhi, in 6 - L. monocytogenes, E. coli, in 15 - C. botulinum, E. coli. Of all the isolated microbial strains, Escherichia coli made up the largest number: this microorganism was isolated from all mites. L. monocytogenes appeared to be the least isolated: 38 of 152 mites were its carriers. Salmonellosis pathogen circulation was detected in 123 mites out of 152 examined specimens. The biological properties of all the isolated microbial cultures corresponded to their classical characteristics. Microorganisms of the genus Clostridium isolated from the mites on the Kitt-Tarozzi nutrient medium caused uniform turbidity of the nutrient medium, which indicates that this bacterial strain belongs to serovars C, D, E and В. The data obtained indicate the need for annual veterinary control of the grazing areas for the presence of natural foci, the reservoirs of pathogens which are pasture mites. During the period of ixodid mites mass attack it is necessary to carry out acaricide treatments of animals with repellent and acaricide preparations that will not only increase their productivity, but will also allow preventing infectious diseases.

Population dynamics of the mite, Tetranychus urticae Koch (acarina: tetranychidae) under acaricide treatment on two varieties of peach and one variety of nectarine in the province of El-Hajeb (Morocco)

Population dynamics of the mite, Tetranychus urticae Koch (acarina: tetranychidae) under acaricide treatment on two varieties of peach and one variety of nectarine in the province of El-Hajeb (Morocco)

Population dynamics of the mite, Tetranychus urticae Koch (acarina: tetranychidae) under acaricide treatment on two varieties of peach and one variety of nectarine in the province of El-Hajeb (Morocco)

The population dynamics of Tetranychus urticae Koch on two varieties of peach (Prunus persica var. Royal Majestic, and Prunus persica var. Kaweah) and one variety of nectarine (Prunus persica var. nucipersica var. Zephyr) were monitored for three years from 2019 to 2022. The results of this study showed that over the course of these three years, infestation peaks occurred in March and declined later in October. For all three varieties, the infestation profile varied from year to year. The Royal Majestic variety was the most infested by T. urticae, with average infestation percentages of 57.06%, 44.11%, and 50.97%, respectively during the three years. As for the two other varieties, the infestation was less pronounced during the three years with average infestation percentages of 31%, 15.42%, and 15.50% on Kaweah and 5.31%, 29.21%, and 26.06% on Zephyr. The results of intra-plant infestation showed that during that during this study periods, the lower stratum was the one with the highest average infestation percentages, with average infestation percentages of 57.29%, 26.08%, and 28.37% respectively on the Royal Majestic, Zephyr, and Kaweah varieties. Concerning the middle stratum, the percentages of infestation are 53.19%, 19.42%, and 19.96% respectively for the Royal Majestic, Zephyr, and Kaweah varieties. For the upper stratum the percentages of infestation are 47.87%, 11.56%, and 9.54% respectively for the Royal Majestic, Zephyr, and Kaweah varieties.

Temporal Dynamics of Anaplasma marginale Infections and the Composition of Anaplasma spp. in Calves in the Mnisi Communal Area, Mpumalanga, South Africa.

Bovine anaplasmosis, caused by Anaplasma marginale, is one of the most important tick-borne diseases of cattle. Anaplasma marginale is known to be present in the Mnisi community, Mpumalanga Province, with frequent cases of anaplasmosis reported. This study investigated the infection dynamics in calves (n = 10) in two habitats in the study area over 12 months. A duplex real-time PCR assay targeting the msp1β gene of A. marginale and the groEL gene of A. centrale confirmed the presence of A. marginale in five calves in a peri-urban area from the first month, but in only two calves at the wildlife-livestock interface and only after six months. These results were confirmed by 16S rRNA microbiome analysis. Over 50 A. marginale msp1α genotypes were detected in the calves along with five novel Msp1a repeats. Calves in the peri-urban area were more likely to be infected with A. marginale than calves in the wildlife-livestock interface. Cattle management, acaricide treatment, and cattle density could explain differences in infection prevalence in the two areas. Our results revealed that most calves were superinfected by distinct A. marginale strains within the study period, indicating continuous challenge with multiple strains that should lead to robust immunity in the calves and endemic stability in the area.

Effects of Neighborhood-Scale Acaricidal Treatments on Infection Prevalence of Blacklegged Ticks (Ixodes scapularis) with Three Zoonotic Pathogens.

Acaricides are hypothesized to reduce human risk of exposure to tick-borne pathogens by decreasing the abundance and/or infection prevalence of the ticks that serve as vectors for the pathogens. Acaricides targeted at reservoir hosts such as small mammals are expected to reduce infection prevalence in ticks by preventing their acquisition of zoonotic pathogens. By reducing tick abundance, reservoir-targeted or broadcast acaricides could reduce tick infection prevalence by interrupting transmission cycles between ticks and their hosts. Using an acaricide targeted at small-mammal hosts (TCS bait boxes) and one sprayed on low vegetation (Met52 fungal biocide), we tested the hypotheses that infection prevalence of blacklegged ticks with zoonotic pathogens would be more strongly diminished by TCS bait boxes, and that any effects of both acaricidal treatments would increase during the four years of deployment. We used a masked, placebo-controlled design in 24 residential neighborhoods in Dutchess County, New York. Analyzing prevalence of infection with Borrelia burgdorferi, Anaplasma phagocytophilum, and Babesia microti in 5380 nymphal Ixodes scapularis ticks, we found little support for either hypothesis. TCS bait boxes did not reduce infection prevalence with any of the three pathogens compared to placebo controls. Met52 was associated with lower infection prevalence with B. burgdorferi compared to placebo controls but had no effect on prevalence of infection with the other two pathogens. Although significant effects of year on infection prevalence of all three pathogens were detected, hypothesized cumulative reductions in prevalence were observed only for B. burgdorferi. We conclude that reservoir-targeted and broadcast acaricides might not generally disrupt pathogen transmission between reservoir hosts and tick vectors or reduce human risk of exposure to tick-borne pathogens.

Optimal control of a tick population with a view to control of Rocky Mountain Spotted Fever.

In some regions of the Americas, domestic dogs are the host for the tick vector Rhipicephalus sanguineus, and spread the tick-borne pathogen Rickettsia rickettsii, which causes Rocky Mountain Spotted Fever (RMSF) in humans. Interventions are carried out against the vector via dog collars and acaricidal wall treatments. This paper investigates the optimal control of acaricidal wall treatments, using a prior model for populations and disease transmission developed for this particular vector, host, and pathogen. It is modified with a death term during questing stages reflecting the cost of control and level of coverage. In the presence of the control, the percentage of dogs and ticks infected with Ri. rickettsii decreases in a short period and remains suppressed for a longer period, including after treatment is discontinued. Risk of RMSF infection declines by 90% during this time. In the absence of re-application, infected tick and dog populations rebound, indicating the eventual need for repeated treatment.

Co-infections of major tick-borne pathogens of dogs in Andhra Pradesh, South India.

Implementing hemoprotozoan control strategies in dogs has become difficult because of the co-infections. A multiplex polymerase chain reaction (PCR) was carried out for simultaneous detection of the co-infections of Babesia gibsoni, B. vogeli, Hepatozoon canis and Ehrlichia canis from dogs (N = 442) in Andhra Pradesh, South India. The co-infection combinations were classified as (i) B. gibsoni + B. vogeli + E. canis + H. canis (BEH), (ii) B. gibsoni + B. vogeli + E. canis (BE), (iii) B. gibsoni + B. vogeli + H. canis (BH) and (iv) E. canis + H. canis (EH) groups. The parasite-specific multiplex PCR amplified 18S rRNA gene of B. gibsoni, B. vogeli and H. canis and VirB9 gene of E. canis. The age, gender, breed, medium, living condition and region of dogs were studied as risk factors for co-infections using logistic regression model. Among the co-infections, the incidence was 1.81%, 9.28%, 0.69% and 0.90% for BEH, BE, BH and EH infections, respectively. Young age (< one year), females, mongrels, rural dogs, kennel dogs and presence of ticks were the identified risk factors for overall prevalence of tick-borne pathogens. The incidence of infection was less in rainy season, especially in dogs with a previous acaricidal treatment. The study concludes that the multiplex PCR assay could simultaneously detect natural co-infections in dogs, emphasizing the need for the assay in epidemiological studies to reveal the real pattern of pathogens and select pathogen-specific treatment protocols.

Inspiring Anti-Tick Vaccine Research, Development and Deployment in Tropical Africa for the Control of Cattle Ticks: Review and Insights

Ticks are worldwide ectoparasites to humans and animals, and are associated with numerous health and economic effects. Threatening over 80% of the global cattle population, tick and tick-borne diseases (TTBDs) particularly constrain livestock production in the East, Central and Southern Africa. This, therefore, makes their control critical to the sustainability of the animal industry in the region. Since ticks are developing resistance against acaricides, anti-tick vaccines (ATVs) have been proposed as an environmentally friendly control alternative. Whereas they have been used in Latin America and Australia to reduce tick populations, pathogenic infections and number of acaricide treatments, commercially registered ATVs have not been adopted in tropical Africa for tick control. This is majorly due to their limited protection against economically important tick species of Africa and lack of research. Recent advances in various omics technologies and reverse vaccinology have enabled the identification of many candidate anti-tick antigens (ATAs), and are likely to usher in the next generation of vaccines, for which Africa should prepare to embrace. Herein, we highlight some scientific principles and approaches that have been used to identify ATAs, outline characteristics of a desirable ATA for vaccine design and propose the need for African governments to investment in ATV research to develop vaccines relevant to local tick species (personalized vaccines). We have also discussed the prospect of incorporating anti-tick vaccines into the integrated TTBDs control strategies in the sub-Saharan Africa, citing the case of Uganda.

Incidence and trends of ixodid tick-borne borreliosis and Siberian tick typhus in the Eastern Transbaikalia

Aim. To study the trends and to assess longterm incidence of ixodid tick-borne borreliosis (ITB) and Siberian tick typhus (STT) in Eastern Transbaikalia for the improvement of preventive measures.Materials and Methods. We carried out a retrospective analysis of ITB and STT incidence in different districts of the Eastern Transbaikalia during 2003–2021. Epidemic trends were characterised using linear regression equations.Results. Average annual incidence of ITB in 2003–2021 was 4 cases per 100,000 population. Analysis of two periods (2003–2012 and 2013– 2021) showed an increase in ITB incidence in 2013–2021 (5.1 ± 0.79 per 100,000 population) as compared to 2003–2012 (2.6 ± 0.73 per 100,000 population, p &lt; 0.05). Within 2013–2021 period, there has been a statistically insignificant trend towards decreasing ITB incidence. The incidence of STT was lower than that of ITB and there was no statistically significant trend towards change of this scenario (average annual incidence in 2003– 2021 was 2.1 ± 0.37 per 100,000 population). Between 2012 and 2021, in particular before 2017, the incidence of STT reduced (average annual incidence in 2012–2021 was 1.5 ± 0.43 per 100,000 population). The epidemiological risk of ITB and STT varied across the distinct territories of Eastern Transbaikalia.Conclusion. In order to prevent the incidence of tick-borne diseases, acaricide treatments should be regularly carried out. Amounts of such interventions should be determined depending on the risk of human infection.

Hydrolats from Humulus lupulus and Their Potential Activity as an Organic Control for Varroa destructor

Varroa destructor is a parasitic mite, which is considered a severe pest for honey bees causing serious losses to beekeeping. Residual hydrolats from steam extraction of hop essential oils, generally considered as a waste product, were tested for their potential use as acaricides on V. destructor. Four hop varieties, namely Cascade, Spalt, Victoria, and Mapuche, showed an interesting performance as feasible products to be used in the beekeeping industry. Some volatile oxidized terpenoids were found in the hydrolats, mainly β-caryophyllene oxide, β-linalool, and isogeraniol. These compounds, together with the presence of polyphenols, flavonoids, and saponins, were probably responsible for the promissory LC50 values obtained for mites after hydrolat exposition. Victoria hydrolat was the most toxic for mites (LC50: 16.1 µL/mL), followed by Mapuche (LC50 value equal to 30.1 µL/mL), Spalt (LC50 value equal to 114.3 µL/mL), and finally Cascade (LC50: 117.9 µL/mL). Likewise, Spalt had the highest larval survival, followed by Victoria and Mapuche. Cascade was the variety with the highest larval mortality. In addition, none of the extracts showed mortality higher than 20% in adult bees. The Victoria hydrolat presented the best results, which makes it a good compound with the prospect of an acaricide treatment against V. destructor.

Population dynamics of Rhipicephalus microplus in dairy cattle: influence of the animal categories and correlation with milk production.

Is well known the taurine and zebuine susceptibility to Rhipicephalus microplus. Few are the reports regarding tick population dynamics between the same herd/breed, and because of this, two experiments were performed. In the 1st, the cattle tick population dynamics in dairy nursing calves (reared collective and individually), weaning calves (4-16 months), heifers (17-29 months), cows in lactation and dry cows (≥ 30 months) from the same herd, tick burden and milk production correlation were performed, for two years. R. microplus females (4.5-8.0mm) counts and the milk production were performed every 28 and 14 days, respectively. In the 2nd experiment, bovines belonging to different categories/age (newborn without previous contact with tick; 12-13 months with tick contact since birth; and 23-24 months with tick contact since birth) were experimentally infested with 30,000 R. microplus larvae, to quantify the number of fully engorged females detached from these animals. In the 1st experiment, when the mean counts of tick were ≥ 30 all animals of the group were treated. Nursing calves showed 3-4 peaks of ticks, animals reared individually showed smaller (p ≤ 0.05) tick burden than those reared collectively. Weaning calves (4-8 months) showed 5 tick peaks/year and higher mean tick burden was found than other categories. On the other hand, animals with 17-29 months of age showed smallest (p ≤ 0.05) tick burden, with 3 tick peaks/year. When the animal become lactating the tick burden increase, and 5 peaks/year occurred, and decrease again in dry cows (p ≤ 0.05) showing 4-5 tick peaks/year. Weaning calves and lactating cows received more acaricide treatments (p ≤ 0.05), 18 and 15, respectively. Nursing calves reared individually, and heifers (21-29 months) were the categories that received two acaricide treatments. The more milk the cow produce, more ticks it has (p ≤ 0.05). In the 2nd experiment, more (p ≤ 0.05) fully engorged females were recovered from younger animals than older ones. So, different tick control strategies need to be adopted in different dairy cattle categories, and the tick burden should be considered, once the effect may be more inherent to the animal rather than the strategy adopted.

Seasonal fluctuations of Babesia bigemina and Rhipicephalus microplus in Brangus and Nellore cattle reared in the Cerrado biome, Brazil

BackgroundThe tick Rhipicephalus microplus (Ixodida: Ixodidae, Canestrini, 1888) causes substantial economic and health losses in cattle production and is the main vector of Babesia bigemina (Piroplasmidae: Babesidae, Smith & Kilborne, 1893). Babesia bigemina is responsible for a tick-borne disease known as babesiosis that can cause hemolytic anemia, fever and death. In the study reported here, we investigated the relationship between the number of ticks per animal and the number of B. bigemina cytochrome b gene (cbisg) copies in the blood of Brangus and Nellore cattle reared without acaricidal treatment in the Brazilian Cerrado biome over a 1-year period.MethodsTicks on 19 animals (9 Brangus and 10 Nellore cattle) were counted every 18 days, and blood was collected every 36 days for 12 months. Serological samples were analyzed with an indirect enzyme-linked immunosorbent assay, and genomic DNA was analyzed by conventional PCR and quantitative PCR. The PCR products were sequenced by the Sanger method.ResultsThe Brangus and Nellore breeds showed similar weight development and no clinical signs of babesiosis. Statistically significant differences (P < 0.05) between the breeds were observed for the number of ticks and the number of B. bigemina cbisg gene copies.ConclusionsNo correlation between the number of ticks and the number of circulating copies of cbisg was observed, although Nellore cattle presented with fewer ticks than Brangus cattle and the number of cbisg copies was higher for Nellore cattle than for Brangus cattle.

Assessing the effectiveness of prophylactic treatment strategies for sheep scab

Ovine psoroptic mange (sheep scab) is a condition caused by a hypersensitivity response to the ectoparasitic mite, Psoroptes ovis. It is an animal welfare concern and causes extensive economic losses to the sheep industry worldwide. More effective scab management is required to limit increases in infection prevalence, particularly given growing concerns over acaricide resistance. Here, a stochastic metapopulation model is used to explore the effectiveness of a range of prophylactic acaricide treatment strategies in comparison to no intervention. Over a simulated one-year period, movement control, based on the prophylactic treatment of animals being moved in sales, followed by farm biosecurity of bought in animals, was shown to be the most effective at reducing scab risk and more cost-effective than no intervention. Localised targeting of prophylaxis in areas of high scab prevalence was more effective than using prophylaxis at random, however, this localised effect declined post-treatment because of the import of infected animals. The analysis highlights the role of the movement of infected animals in maintaining high levels of scab infection and the importance of reducing this route of transmission to allow localised management to be effective.