Tick Boophilus Research Articles

Degree-days and off-host longevity of cattle fever ticks, Boophilus spp. (Acari: Ixodidae) in south Texas pastures.

Cattle fever ticks, Boophilus microplus (Canestrini) and Boophilus annulatus (Say), are native to Eurasia and have invaded the New World as vectors of bovine Babesiosis. Due to severe losses in livestock production, an eradication program by the USDA was established. Premises infested with Boophilus ticks are subject to regulatory oversight that includes acaricide treatment and quarantine. The quarantine duration varies between summer through winter and is based on the available information on the persistence of the off-host stages in pastures far from south Texas. The objective of this study was to assess the specific effect of thermal stress measured in degree-days on the longevity of B. annulatus and B. microplus off-host stages in south Texas pastures. Our results demonstrate that the longest off-host persistence for B. annulatus was 142 days under canopied habitat in the winter and 130 days in the summer. On the other hand, B. microplus off-host persistence was 113 days under canopy and 103 days in exposed habitat, both in winter. The results indicate that temperature was a key variable that prolonged the survival of B. annulatus but not B. microplus. In areas such as south Texas at the northernmost extent of B. microplus range, where mild winters prevail, we found a maximum persistence of less than 4 months (113 days), very close to the previous published record of 116 days. A reduction in the Texas pasture quarantine period from 9 months to 6 months would be justified for this species.

Rhipicephalus annulatus, R. australis or R. microplus? Discordance between morphological and genetic data among three cattle tick species.

The taxonomy of ticks of the subgenus Boophilus has been extensively debated and is often complicated by the high intraspecific variation of morphological features between species. Notably, the cattle tick Rhipicephalus microplus is a species complex consisting of Rhipicephalus annulatus, Rhipicephalus australis and the three mitochondrial clades (A-C) of R. microplus. To gain insight into the taxonomic status of this species complex, we performed morphological and molecular analyses on these cattle ticks across four states in peninsular Malaysia. We morphologically identified 60 males and 104 females of R. microplus, 298 males and 374 females of R. australis, and one R. annulatus male in our field collection, of which the latter two species have never been recorded in Malaysia. However, all three morphologically identified species were molecularly assigned as R. microplus clade A based on the barcoding cytochrome oxidase subunit I (COI) analysis. The discrepancy between morphological and genetic data highlights an urgent need for further exploration and in-depth research into the taxonomic status of these sympatric tick species.

Ekstrak Kulit Buah Kakao (Theobroma cacao L.) Limbah Perkebunan Berpotensi sebagai Akarisida Alami Terhadap Caplak Boophilus microplus

This study was aims to exploit the potential waste of cocoa pod (Theobroma cacao L.) as a natural acaricide in ticks (Boophilus microplus). The study was conducted with a two-variable completely randomized design (CRD) with two repetitions. The sample does not differentiate between sex, body weight, and length of about 0.8 - 1 cm. Each 5 ticks were treated as follows: treat 1 extract of 10% cocoa pod husk; treatment 2 20% cocoa pod skin extract; treatment 3 30% cocoa pod husk extract; treatment 4 negative control; treat 5 positive controls. In the first variable the tick was treated with methanol extract, while in the second variable the ethanol extract was treated with 10%, 20%, 30% respectively, negative control and positive control. In treatment I used 25 ticks plus treatment II 25 ticks. Each treatment was repeated to avoid data bias so that a total of 100 ticks were used. The results showed that the cocoa pod husk extract had the best killing power at a concentration of 30% with methanol solvent at 6.21 hours while ethanol solvent at 5.91 hours. The use of extraction materials has not been able to compensate for the use of synthetic materials that can kill in minutes.

Epidemiological, Clinical and Diagnostic Studies on Blood Parasites in Cattle and Buffaloes in ElBehera Provence

The present work was carried out to determine epidemiological, clinical and diagnostic state of bovine piroplasmosis. 148 suspected diseased animals in different locations in El Behera Provence including 123 cattle and 25 buffaloes were examined clinically and microscopically in addition to tick examination. Boophilus microplus tick was the main vector in transmission of Babesia species. But in this study found that T.annulata may be transmitted by Boophilus tick and observed decrease in Hyalomma anatolicum which consider the proven vector of T. annulata in cattle. The age susceptibility of piroplasmosis showed 4 calves aged below one week, free from tick and infected with Theileriosis clinically and confirmed by PCR ,this indicate intrauterine or cloistral transmission of Theileriosis. The variation of the clinical finding of piroplasmosis depends upon tick population, degree of virulence of the parasite, native breed or foreign breed, age of animal, previously infected or not and the immune status of the animal. For diagnosis of piroplasmosis in blood, lymph and tick we depend on microscopic examination of Giemsa stained (blood, lymph and hemolymph) smear and PCR technique. Selected 30 samples from blood and tick were examined by PCR for detection of piroplasmosis. PCR is much more sensitive than ME either in clinically infected or apparently healthy animals (carriers).

Dynamics of Boophilus Ticks and its Role in Transmission of Piroplasms at Behaira District

Dynamics of Boophilus tick was investigated at Behaira district. A total number of (86) out of (839) cattle (10.25%) were infected with Boophilus spp. The prevalence of Boophilus spp infection predominated in summer season (21.33%) followed by autumn (10.78%) and last spring (6.34%) and the lowest burden was in winter. Concerning the locality, El- Dalangat was representing the highest locality infected with tick vector (17.39%) and according to age, the animals less than one year was the lowest one infected with tick (5.17%) then animals which were aged 1-3 years (9.8%) and animals more than 3 years (10.75%).The neck and dewlap representing the highest predilection seats of Boophilus spp. (81.39%) in cattle and the lowest one was udder (2.94%). Hemolymph and salivary gland samples of 56 Boophilus spp were extracted, stained by Giemsa and microscopically inspected under oil immersion lens. the total infection of Hemolymph with ookinete was (28.57%) that increased in summer season (32.14%) and according to salivary gland smears of Boophilus spp. showed that the total infection rate was (21.43%) and increased in summer (25%) also winter had no infection for both. Electron microscopic examination of salivary gland of Boophilus spp. showed a prescence of electron-dense and more irregular-shaped sporozoites were detected in some infected cells.

Are brucellosis, Q fever and melioidosis potential causes of febrile illness in Madagascar?

Brucellosis, Q fever and melioidosis are zoonoses, which can lead to pyrexia. These diseases are often under-ascertained and underreported because of their unspecific clinical signs and symptoms, insufficient awareness by physicians and public health officers and limited diagnostic capabilities, especially in low-resource countries. Therefore, the presence of Brucella spp., Coxiella burnetii and Burkholderia pseudomallei was investigated in Malagasy patients exhibiting febrile illness. In addition, we analyzed zebu cattle and their ticks as potential reservoirs for Brucella and C. burnetii, respectively. Specific quantitative real-time PCR assays (qPCRs) were performed on 1020 blood samples drawn from febrile patients. In total, 15 samples (1.5%) were Brucella-positive, mainly originating from patients without travel history, while DNA from C. burnetii and Bu. pseudomallei was not detected.Anti-C. burnetii antibodies were found in four out of 201 zebu serum samples (2%), whereas anti-Brucella antibodies could not be detected. Brucella DNA was detected in a single zebu sample. Three out of 330 ticks analyzed (1%) were positively tested for C. burnetii DNA but with high Ct values in the qPCR assay. Our data suggest that zebus as well as Amblyomma and Boophilus ticks have to be considered as a natural reservoir or vector for C. burnetii, but the risk of cattle-to-human transmission is low. Since bovine brucellosis does not seem to contribute to human infections in Madagascar, other transmission routes have to be assumed.

Designing and modeling of complex DNA vaccine based on tropomyosin protein of Boophilus genus tick.

Boophilus tick is a bloodsucking ectoparasite that transfers some pathogens, reducing production and thus leading to economical losses in the cattle industry. Tropomyosin (TPM) protein is a salivary protein, has actin regulator activity, and plays an important role in immune reactions against parasites. In the current study, besides developing a safe, effective, and broad spectrum protective measure against Boophilus genus tick based on TPM protein, we attempted to minimize possible problems occurring in the design of polytopic vaccines. Briefly, the steps that were followed in the present study were as follows: retrieving sequences and finding the mutational/conservative regions, selecting consensus and high immunogenic epitopes of B and CD4(+) T cells by different approaches, three-dimensional structure (3D structure) prediction and representation of epitopes and highly variable/conserve regions, designing vaccinal construct by fusion of B and T cell epitopes by special patterns and improving immunogenicity, evaluation of the constructs' primary structure and posttranslational modification, calculation of hydrophobic regions, reverse translation, codon optimization, open reading frame checking, insertion of start/end codon, Kozak sequence, and finally constructing the DNA vaccine. Variation plot showed some shared epitopes among the ticks' and mites' species that some might be effective only in some species. Finally, by following the steps mentioned above, two constructs for B and T cells were achieved. Checking constructs revealed their reliability and efficacy for in vitro production and utilization. Successful in silico modeling is an essential step of designing vigorous vaccines. We developed a novel protective and therapeutic vaccine against Boophilus genus (based on TPM protein). At the next step, constructed DNA vaccine would be produced in vitro and administrated to cattle, and its potency to induction of immune response and protection against Boophilus genus as well as other ticks and mites will be evaluated.

Detection of Borrelia theileri in Rhipicephalus geigyi from Mali

Disease burden within cattle is a concern around the world. Bovine borreliosis, one such disease, is caused by the spirochete Borrelia theileri transmitted by the bite of an infected Rhipicephalus (Boophilus) species tick. A number of species within the genus are capable of transmitting the agent and are found on multiple continents. Cattle in the West African nation of Mali are infested with four species of Rhipicephalus ticks of the subgenus Boophilus: Rhipicephalus annulatus, Rhipicephalus microplus, Rhipicephalus decoloratus, and Rhipicephalus geigyi. To date, no reports of B. theileri within Mali have been documented. We tested 184 Rhipicephalus spp. ticks by PCR that were removed from cattle at a market near Bamako, Mali. One tick, R. geigyi, was positive for B. theileri, which confirmed the presence of this spirochete in Mali.

The Use of Sour Soup (Annona murricata) Seed Powder as Acaricide on Cow and Goat

This research was aimed to study curative effect of sour soup seed powder on cattle invested with ticks and goat infected with scabies. This study was using 12 cattle invested with ticks and 12 goats with scabies. The cattle divided into 4 groups (S1, S2, S3 and S4) while goats were divided into 3 groups (K1, K2, and K3) equally. For cattle with ticks group S1 received water (control group), while group S2, S3, and S4 received 1%, 5%, and 10% sour soup powder respectively. Ticks that fell to the ground and not engorged were collected and identified. Statistical analysis showed that all concentrations of sour soup were effective in paralyzing and or killing ticks of the genera Boophilus sp. and Dermacentor sp. but were not effective against Rhipicepalus sp. For goats with scabies, groups K1, K2, and K3 received 1, 5 and 10% sour soup powder respectively mixed with water applied to whole area of infected and uninfected skin surrounding infected area. Number of mites per cm2 before and after treatment was counted. Statistical analysis showed that 1, 5, and 10% sour soup powder effective in reducing the number of scabies mites on day 1 and 7 after treatment and were significantly different from those number of mites before treatment (P0.01). Statistical analysis also showed that no significant difference among concentration of sour soup seed powder in decreasing the number of mites (P0.05).

Conservation of Transmission Phenotype of <I>Anaplasma marginale</I> (Rickettsiales: Anaplasmataceae) Strains Among <I>Dermacentor</I> and <I>Rhipicephalus</I> Ticks (Acari: Ixodidae)

Before the eradication of Boophilus ticks from the United States, Rhipicephalus (Boophilus) microplus (Canestrini) and Rhipicephalus (Boophilus) annulatus (Say) were important biological vectors of the cattle pathogen Anaplasma marginale Theiler. In the absence of Boophilus ticks, A. marginale continues to be transmitted by Dermacentor ticks. However, a few U.S. strains are not transmissible by Dermacentor andersoni Stiles, Dermacentor variabilis (Say), or both, raising the question of how these strains evolved and how they are maintained. We hypothesize that the U.S. non-Dermacentor-transmissible strains of A. marginale were formerly Boophilus-transmitted strains that have been maintained by a combination of persistent infection and mechanical transmission since the eradication of their biological vector from the United States. To test this hypothesis, we attempted to transmit a well-documented non-Dermacentor-transmissible A. marginale strain (Florida), by using D. andersoni and the two Boophilus species that formerly occurred in the United States. For comparison, we examined tick-borne transmission of a strain of A. marginale (Puerto Rico), which has previously been shown to be transmissible by both D. andersoni and B. microplus. All three species of tick transmitted the Puerto Rico strain, and immunohistochemical (IHC) analysis confirmed the presence ofA. marginale colonies in their salivary glands. All three tick species failed to transmit the Florida strain. Although both D. andersoni and B. microplus acquired transient midgut and salivary gland infections after acquisition feeding, we were unable to detect colonies of the Florida strain in the salivary glands with IHC. This demonstrates that the transmission phenotype ofA. marginale strains is conserved among tick species, and it suggests that the failure of the Florida strain to be transmitted by ticks is related to a general inability to efficiently invade or replicate in tick cells, rather than to a failure to invade or replicate in cells of a specific tick species.

INVESTIGATION OF BM86 GENE ANALOG SEQUENCE IN SOME IRANIAN POPULATIONS OF HYALOMMA ANATOLICUM SPECIES

Ticks are an important problem among zoonotic diseases. Main veterinary species of hard ticks are: Hyalomma sp. Boophilus sp and Rhipicephalus sp. Among them Hyalomma sp. have widespread distribution in Iran and Middle East. The best method to control Hyalomma sp. is immunological one, by using antigens, which causes immunologic and physiologic reactions in host.Bm86 is one of the best antigens, vaccines of which have been produced in Cuba and Australia (TICKGARD, GAVAC).In tracing for Bm86 homologue in H.anatolicum and phylogenic research based on the construction and characterization of this gene. H.anatolicum populations were collected from various regions of Iran and subjected to DNA extraction. After PCR reaction, comparison sequencing of this gene in Hyalomma and Boophilus ticks indicated that probably there are some conserved regions inside this gene in DNAMAN program. More differences between sequences of this gene in H.anatolicum populations collected from Iran and the one from India show that biogeographical separations affect genomic characters.

Microclimate influence in a physiological model of cattle-fever tick ( Boophilus spp.) population dynamics

Since their official eradication from the US in 1943, the cattle-tick species Boophilus microplus and Boophilus annulatus, vectors of bovine babesiosis, frequently have penetrated a quarantine zone established along the Texas–Mexico border designed to exclude them. Inspection and quarantine procedures have eradicated reinfestations successfully within the US, but increasing acaricide resistance in Mexican B. microplus populations poses a threat to future eradication efforts. Better understanding of interrelationships among Boophilus populations, their hosts, and vegetation communities in south Texas could improve prediction of the behavior of reintroduced Boophilus populations and increase management options. To this end, we constructed a simulation model to evaluate how microclimate, habitat (i.e. vegetation) heterogeneity, and within-pasture cattle movement may influence dynamics of Boophilus ticks in south Texas. Unlike previous Boophilus tick models, this model simulates dynamics at an hourly time-step, calculates all off-host dynamics as functions of temperature and relative humidity, and runs with ground-level microclimate data collected bi-hourly in three different habitat types. Sensitivity analysis of the model showed that temperatures and relative humidities created by habitat type, as well as engorged female mass, influenced tick population dynamics most strongly. Host habitat selection, initial number of larvae per cow, and the number of cells into which the simulated pasture was divided also had a strong influence. Population dynamics appeared moderately sensitive to the proportion of Bos indicus in cattle genotypes and the larval attachment rate, while appearing relatively insensitive to factors such as mortality rate of engorged females. When used to simulate laboratory experiments from the literature, the model predicted most observed life-history characteristics fairly well; however, it tended to underestimate oviposition duration, incubation duration, and egg mortality and overestimate larval longevity, especially at low temperatures and high humidities. Use of the model to predict Boophilus population dynamics in hypothetical south Texas pastures showed that it reasonably generated qualitative patterns of stage-wise abundances but tended to overestimate on-host tick burdens. Collection and incorporation of data that appear not to exist for Boophilus ticks, such as larval lipid content and lipid-use rates, may improve model accuracy. Though this model needs refinements such as a smaller spatial resolution, it provides insight into responses of B. microplus or B. annulatus populations to specific weather patterns, habitat heterogeneity, and host movement.

Displacement of Boophilus decoloratus by Boophilus microplus in the Soutpansberg region, Limpopo Province, South Africa.

Boophilus ticks (n = 25,987) were collected from cattle at 30 communal dip tanks and five commercial farms in the Soutpansberg region, Limpopo Province, South Africa, between May 1999 and December 2001. Only 6.6% were Boophilus decoloratus, while 93.4% were Boophilus microplus, a tick that had not been reported from this area previously. B. microplus was the most common Boophilus tick on communal dip tank cattle, while B. decoloratus was more commonly found on commercial farms. Where the two species occurred together, B. microplus tended to displace B. decoloratus. The displacement was almost complete at the communal dip tanks, while on the commercial farms the population change was still in progress at the end of the survey. The present study demonstrated that a postulated reproductive interference was insufficient in preventing B. microplus from spreading when the climatic conditions were favourable to this species, as the displacement in most of the areas appeared to be rapid and complete.

Simulating detection of cattle-fever tick ( Boophilus spp.) infestations in rotational grazing systems

To evaluate the relative influence of ecological and management factors on the probability of detecting cattle-fever tick ( Boophilus microplus and Boophilus annulatus) infestations in rotational grazing systems, we adapted a simulation model of Teel et al. [J. Range Manage. 51 (1998) 501] that examines interactions among Boophilus ticks, cattle, and habitat type under rotational grazing systems developed for semi-arid shrublands of south Texas. We added a submodel that estimates probability of inspectors detecting Boophilus-tick infestations when examining 1, 20, 40, or 80 cows in a tick-infested herd of 80 cattle. Results indicate that probability of detecting infestations depends most on season of initial infestation; less heavily on rotational grazing strategy, habitat type, and number of cows inspected; and only moderately on initial number of infesting tick larvae. Results showed high detection probabilities (≥0.95) usually exist as temporal windows of opportunity during brief but definite periods; outside these windows, detection of existing infestations becomes poor. Each halving of the number of cows inspected tended to shorten duration of these windows by approximately 40%. Probability of detecting tick infestations, however, also depends strongly on inspector training, cow behavior, and weather, factors that we set as implicit constants. Models such as this one can indicate gaps in knowledge about the influence of biophysical and human factors on detection efforts in tick eradication or control programs, estimate magnitude and duration of Boophilus-tick infestations, and indicate potentially favorable inspection periods.

Babesiosis and heartwater: threats without boundaries.

Suppose one of your clients from southern Florida starts talking about cattle egrets while you are vaccinating her cat. It seems she found a nearly dead egret near the cattle pen a few days ago, picked it up, and noticed a number of what looked like small ticks on the legs. Or, suppose you are called out to a small dairy in central Texas to look at some cows that are feverish and anemic. The first animal you examine has a few brown ticks attached just under the tail. Finally, perhaps you are looking at a lame tortoise for a reptile fancier, a new client, and find a large, colorful tick on a hind leg, well up under the shell. Ring any bells? Egrets are great hosts for the immature stages of Amblyomma ticks and have been captured and marked in the eastern Caribbean, then recaptured in the Florida Keys. Those cattle ticks in Texas might be acaricide-resistant Boophilus ticks that originated in Mexico. The Amblyomma tick on the tortoise could well have "hitch-hiked" all the way from South Africa. By now you remember that both Amblyomma and Boophilus ticks are efficient vectors of two tickborne diseases in this hemisphere, heartwater (in the case of Amblyomma) and babesiosis (transmitted by Boophilus ticks). Both of these diseases are exotic to the United States, and because our livestock are considered to be totally susceptible, an introduced infection could result in high initial death losses (approximately 70%); thus, both the ticks and the diseases pose immediate threats to the health and economic security of United States animal industries. Most importantly, you, whether as a small animal or large animal practitioner, are the first line of defense against such exotic diseases and their vectors.

Introduced ticks and tick-borne diseases: the threat and approaches to eradication.

Exotic tick species and tick-borne diseases are serious threats to live-stock, companion animals, and wildlife in the United States. Recurring introductions of exotic tick species into the United States are a significant indicator of the degree of risk. Successful tick-eradication campaigns, such as the national program that eradicated Boophilus annulatus and B. microplus from the United States, the Cattle Fever Tick Eradication Program of the US Department of Agriculture's Veterinary Services that protects against the re-entry and dissemination of Boophilus ticks from Mexico back into their former haunts in the southern states, and the eradication action that eliminated Rhipicephalus evertsi from a game park in Florida, are sources of useful information that aid in elucidating essential elements of successful eradication programs. Examples of failed eradication programs in places such as Puerto Rico and St. Croix also have heuristic value. Among the varieties of tick species and related infectious agents that threaten the United States, Boophilus ticks and bovine babesiosis, Amblyomma species (especially the tropical bont tick) and heartwater, and equine babesiosis, for which endemic vectors exist, are of special concern. Risk assessments to accumulate, evaluate, and synthesize information needed to appraise risks, consequences, and preparedness are necessary not just to inform federal, state, and local officials, as well as producers and stakeholders, but also to facilitate the creation of emergency response plans.

Cattle tick (Boophilus microplus) in Victoria on horses from Queensland

Cattle tick (Boophilus microplus) in Victoria on horses from Queensland

Cattle tick (Boophilus microplus) in Victoria on horses from Queensland.

Cattle tick (Boophilus microplus) in Victoria on horses from Queensland.

Influence of acaricide resistance on cattle-fever tick (Boophilus spp.) infestations in semi-arid thornshrublands: a simulation approach.

Cattle-fever tick (Boophilus microplus and B. annulatus) populations that develop acaricide resistance become more difficult to control or eradicate. We used a simulation model to assess the direct and indirect effects of interactions among season, habitat type, grazing strategy, and acaricide resistance on the ability to eradicate Boophilus infestations in semi-arid thornshrublands of Texas, USA. Season of infestation appeared to have the strongest effect, with infestations begun on 27 September (autumn) tending to die out sooner than those begun on 1 March (spring) and to remain undetected. Habitat type had the next strongest effect, with infestations surviving much longer as canopy cover increased from uncanopied buffelgrass (Cenchrus ciliaris) habitats to mesquite (Prosopis glandulosa)-canopied grass habitats. Acaricide resistance had a moderate effect; as expected, highly resistant tick populations survived longer than those with no acaricide resistance. The importance of grazing strategy varied with changes in habitat type: as canopy cover increased, infestation duration increased faster under continuous grazing than under rotational grazing strategies. Importance of grazing strategy also varied with acaricide resistance: detected tick populations with no and slight acaricide resistance subjected to acaricide treatments tended to survive longer under rotational grazing than continuous grazing, due to reduced contact with a treated host. Populations with moderate and high resistance behaved more like untreated populations, tending to survive longer under continuous, rather than rotational, grazing, because they experienced less mortality on a treated host. Assuming acaricide treatments at 2-week intervals and maintenance of cattle in infested pastures, results indicate that, for each habitat type, infesting ticks have a threshold of acaricide resistance below which one can eradicate them faster with continuous grazing than with rotational grazing. As canopy cover increases, this threshold appears to shift from high resistance (in grass) to slight resistance (in mesquite).

A model to simulate the effect of vaccination against Boophilus ticks on cattle

This paper describes a vaccination model to simulate the effect of cattle vaccination with concealed antigens on Boophilus tick spp. The model considers the vaccination effect in three parts: antibody titer, accumulation of damaging vaccination effects by parasite stages, and the effect of accumulated damage on all tick life stages. Biological parameters for ticks and hosts, as well as parameters describing tick–host interaction, were included. The validity of this model, integrated with the TICKSIM simulation program, was demonstrated for the Bm86-containing vaccine Gavac™ by comparing simulated and real data for several geographic locations in the Americas. All model parameters were estimated using field data collected in the different geographic locations. The model sensitivity to changes in antibody titer level and titer half-life was studied, and the impact on tick population density of changes in these parameters was evaluated. Simulation results showed that to achieve a higher level of tick control, an increase in the maximum antibody titer levels was more important than extending titer half-life in geographical locations with short seasonal peaks of tick infestation. The TICKSIM program, integrated with the new vaccination model, proved to be a framework for designing and evaluating tick control strategies, including vaccination with Gavac™.