Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Tick Control”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 379 records · Page 21Linked to original sources
PubMed2001

A longitudinal study of disease incidence and case-fatality risks on small-holder dairy farms in coastal Kenya.

A longitudinal study was carried out in the coastal lowlands coconut-cassava agro-ecological zone of Kaloleni Division, Coast Province, Kenya between June 1990 and December 1991 to estimate disease incidence and cause-specific case-fatality risk in an average of 120 cattle in 26 small-holder dairy herds kept in two grazing-management systems. East Coast fever (ECF) was the predominant disease diagnosed; the mean monthly incidence rate was 2.5 and 6.9% in animals < or = 18 months of age under stall-fed and herded-grazing systems, respectively. In cattle > 18 months of age, the monthly incidence rate was < 1%. The 6-month ECF incidence rate was 20+/-8% (S.E.) in the stall-feeding system compared with 39+/-7% in the herded-grazing systems. There was a gradual increase in antibody prevalence with age to over 90% in cattle over 18 months of age in herded-grazing systems, whilst less than a third of cattle in the stall-feeding systems were sero-positive at any age. Overall accumulated mortality to 18 months of age was estimated to be 56%. Annual mortality in cattle > 18 months averaged 9%. Cattle managed in the herded-grazing system had a 60% higher mortality, although not significantly so, than those fed in stalls. Deaths due to ECF accounted for over two-thirds of the deaths. ECF was then the major disease constraint to small-holder dairy production in the coconut zone of coastal Kenya. Clinical cases occur the whole year round (especially in young stock)--despite apparent tick control, and in both herded-grazing and stall-feeding system.

Age Factors↗
PubMed1985

Treatment of field cases of East Coast fever with halofuginone lactate.

In a series of field trials 48 (55%) of 88 field cases of East Coast fever treated with halofuginone lactate recovered and survived and 40 (45%) died while 31 (86%) of 36 untreated control animals died of East Coast fever and five (14%) recovered. For cases diagnosed and treated early a 100% recovery rate was achieved. A single dose at 1.2 mg/kg body weight per os was adequate. Recovery rate was only 36% for cases diagnosed and treated at an advanced stage. Such cases required two doses at 1.2 mg/kg or a combination of 1.2 and 2.4 mg/kg body weight given at about two days interval. The temperature dropped to normal levels within 48 h of treatment and schizonts started degenerating as early as 24 h after treatment and had disappeared by 48 to 72 h. Piroplasms were not affected by the drug. Recovered animals remained free of East Coast fever for periods up to 12 months of observation despite continuous tick challenge. It was concluded that, with early detection and treatment augmented with proper tick control, outbreaks of East Coast fever can be effectively controlled with halofuginone lactate.

Animals↗
PubMed1996

Evaluation of permethrin-impregnated cotton balls as potential nesting material to control ectoparasites of woodrats in California.

The dusky-footed woodrat, Neotoma fuscipes Baird is a natural reservoir of the Lyme disease spirochete, Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner, in California. To investigate the potential of host-targeted insecticide to control the tick vectors of B. burgdorferi, permethrin-impregnated or untreated cotton balls were distributed in metal cylinders as potential nesting material adjacent to 95 woodrat houses in chaparral-covered rangeland. Laboratory experiments demonstrated that adult woodrats would enter the cylinders and construct nests from permethrin-treated or untreated cotton. The residual concentration of permethrin did not vary significantly during an 11-mo period and remained > 60% of the registered insecticidal formulation (7.5% [AI] by cotton weight). The abundance of 4 species of ticks (Ixodes neotomae Cooley; the western blacklegged tick I. pacificus Cooley & Kohls; I. woodi Bishopp; and the Pacific Coast tick, Dermacentor occidentalis Marx) infesting woodrats was similar in the treatment and control areas. Although > 90% of the cotton disappeared from the metal cylinders in both areas, examination of 8 active woodrat houses revealed that small amounts of cotton had been incorporated into the nest cups of only 25%. In contrast, the abundance of the flea Orchopeas sexdentatus (Baker) decreased significantly in the treatment area only. Spirochetes were not detected in 168 adult O. sexdentatus fleas that had fed on spirochetemic woodrats, which demonstrates that this flea is an inefficient host of B. burgdorferi. We conclude that the use of permethrin-impregnated cotton as potential nesting material is ineffective for controlling ticks associated with the dusky-footed woodrat in brushlands, but this methodology may be useful for reducing populations of sylvatic fleas.

Animals↗
PubMed2002

Identification and molecular characterization of a chitinase from the hard tick Haemaphysalis longicornis.

A cDNA encoding tick chitinase was cloned from a cDNA library of mRNA from Haemaphysalis longicornis eggs and designated as CHT1 cDNA. The CHT1 cDNA contains an open reading frame of 2790 bp that codes for 930 amino acid residues with a coding capacity of 104 kDa. The deduced amino acid sequence shows a 31% amino acid homology to Aedes aegypti chitinase and a multidomain structure containing one chitin binding peritrophin A domain and two glycosyl hydrolase family 18 chitin binding domains. The endogenous chitinase of H. longicornis was identified by a two-dimensional immunoblot analysis with mouse anti-rCHT1 serum and shown to have a molecular mass of 108 kDa with a pI of 5.0. A recombinant baculovirus AcMNPV.CHT1-expressed rCHT1 is glycosylated and able to degrade chitin. Chitin degradation was ablated by allosamidin in a dose-dependent manner. The optimal temperature and pH for activity of the purified chitinase were 45 degrees C and pH 5-7. The CHT1 cDNA has an ELR motif for chemokine-mediated angiogenesis and appears to be a chitinase of the chemokine family. Localization analysis using mouse anti-rCHT1 serum revealed that native chitinase is highly expressed in the epidermis and midgut of the tick. AcMNPV.CHT1 topically applied to H. longicornis ticks exhibited replication. This is the first report of insect baculovirus infection of ticks. The importance of AcMNPV.CHT1 as a novel bio-acaricide for tick control is discussed.

Amino Acid Sequence↗
PubMed2000

The role of parasitic diseases as causes of mortality in cattle in a high potential area of central Kenya: a quantitative analysis.

Postmortem records of cattle brought to the Veterinary School in Kabete near Nairobi were examined for a period of 15 years (1984-1998, inclusive) in order to establish the role that parasitic diseases played as causes of death. The cattle were mainly of exotic breeds but a few were crosses or of indigenous breeds. There was a total of 1413 cases of deaths from various diseases of which 177 (13%) were due to parasites. The tick-borne diseases were in high proportions and accounted for 84,7% among the parasitic causes, which represented 10,6% of all the deaths recorded. The main tick-borne disease was East Coast fever (ECF) (65%) followed by heartwater (10,2%), babesiosis (5,1%) and anaplasmosis (4,5%). Hydatidosis was responsible for 7,3% of deaths from parasitic causes. Deaths from ECF were recorded in all the 15 years and in high proportions compared to those due to heartwater (8/15), babesiosis (7/15) and anaplasmosis 5/15). Over the period under consideration, no decline was noted among various disease conditions despite advances made in controlling tick vectors and in the treatment of various parasitic conditions. The area covered by this study has the advantage of having several veterinary-related institutions close by. Hence knowledge and awareness about livestock diseases is relatively high compared to other parts of the country. It is therefore challenging to the Veterinary Department to examine the service delivery systems and other factors that may contribute to the persistent presence of these fatal parasitic conditions of cattle.

Animals↗
PubMed1994

Theileriosis in Zambia: etiology, epidemiology and control measures.

In Zambia, theileriosis manifests itself in the form of Corridor disease (CD), caused by Theileria parva lawrencei, and East Coast fever (ECF), caused by T. parva parva. Of the approximately 3 million cattle in Zambia, 1.4 million are at risk to theileriosis. ECF is found in the Northern and Eastern provinces of the country, while CD appears in Southern, Central, Lusaka and Copperbelt provinces. Theileriosis is a major constraint to the development of the livestock industry in Zambia, with losses of about 10,000 cattle per annum. The disease is spreading at a very fast rate, over-flowing its original borders. The epidemiology is complicated by, among other factors, the wide distribution of the tick vector, Rhipicephalus appendiculatus, which is found all over the country. The current strategy of relying on tick control and therapeutic drugs as a way of controlling the disease is becoming increasingly difficult for Zambia. This is because both curative drugs and acaricides are very costly. Immunization against theileriosis using the infection and treatment method as a way of controlling the disease is becoming increasingly accepted, provided local Theileria stocks are used. This paper reviews the incidence of theileriosis in the last 2 years, 1991 and 1992. It also gives a historical perspective of the disease, epidemiology and control measures presently in use.

Animals↗
PubMed1984

Seasonal prevalence of ixodid ticks on cattle in the Windhoek District of South West Africa/Namibia.

The seasonal prevalence of ixodid ticks was determined over a 2-year period by the weekly removal from at least 5 cattle of all adult ticks and the immature stages of Rhipicephalus evertsi mimeticus in the ears. The highest mean weekly burden was 286,6 adult ticks/cow/week in March 1979, and the lowest 6,9 adult ticks/cow/week in July 1979. Virtually no tick control is practised in this area. Rhipicephalus capensis group adults peaked in the summer from October to March/April. Rhipicephalus evertsi mimeticus adults were present throughout the year, though in slightly greater numbers from November to May. Immature stages of this species in the ears showed a peak in February/March in addition to variably-timed high peaks in the first 2 winters. Hyalomma marginatum rufipes and Hyalomma truncatum peaked from December to March. Very small numbers of Boophilus decoloratus and Rhipicephalus oculatus were recovered. Tick burdens of all major species differed significantly in the 2 study years.

Animals↗
PubMed2000

Invasion of West African cattle by the tick Amblyomma variegatum.

Studies in Cameroon and Burkina Faso examined the invasion process of cattle by adult Amblyomma variegatum Fabricius (Acari: Ixodidae) ticks. Nearly all the ticks picked up in the pasture during grazing were found on the limb ends, near the hooves, where they temporarily attached. Then when the cattle lay down, the ticks moved from the feet towards the predilection sites, where they attached definitively. Many ticks disappeared during this displacement. All the female ticks and approximately 70% of the males were thus unable to attach to the predilection sites as long as the pioneer males had not attached and started to produce attraction-aggregation-attachment pheromones. Nevertheless, A. variegatum females and males attached to the feet in similar numbers during grazing, whether the cattle were already infested or not, indicating that stimuli originating from the hosts are powerful enough to attract both sexes. After attachment of the pioneer males, the number of ticks that successfully reached the predilection sites increased. However, even on infested animals, 40-50% of A. variegatum ticks found near the hooves after the grazing periods disappeared during the night following their capture. When moving from the temporary attachment sites towards the final ones, one-third of the ticks changed the individual host. Considering this two-stage infestation process, it is suggested that a targeted tick control, using a foot-bath, might greatly reduce cattle infestation. In particular, it could be effective in traditional herds, with animals grazing permanently during the day, lying down only once back in the night pen.

Anal Canal↗
PubMed1992

Effects of precocenes on vitellogenesis in the adult female tick, Ornithodoros moubata (Acari: Argasidae).

Vitellogenin (Vg) concentrations in the hemolymph and ovarian development were studied in Ornithodoros moubata after treatment with precocenes 1 (P1) and 2 (P2). Precocene was dissolved in acetone or DMSO and topically applied to the dorsal surface of ticks: (1) at adult ecdysis; (2) 24 h before engorgement; (3) immediately after engorgement; and (4) 24 h after engorgement. Subsequently, P1 and P2 were dissolved in olive oil and injected through the gonopore into the body cavity 24 h after engorgement. Vitellogenin concentration was measured on days 5 and 10 after engorgement and ovarian development was scored on day 10, 20 or 30. Oviposition was also recorded and the average weight of eggs laid by females was determined. No differences in concentration of Vg in the hemolymph occurred between the control ticks and ticks treated topically or by injection with P1 and P2. Precocene did not suppress the synthesis of Vg in O. moubata. However, oviposition was reduced in ticks that survived repeated treatment with high doses of P2 dissolved in acetone.

Animals↗
PubMedDate not supplied

[Toxic effects and in vitro inefficacy of deltamethrin on larvae of Rhipicephalus sanguineus from Goiânia, Goiás, Brazil].

It has been observed that formulations of deltamethrin developed for disinsectization of infested places and control of parasitic arthropods of bovines and equines have frequently been used by breeders of dogs to control ticks in their animals and kennels, but without due consideration of the correct dosage or means of application. With the purpose of evaluating the efficacy of this product on Rhipicephalus sanguineus, bioassays were realized with larvae at 27+/-1 degrees C, UR>80% and light period of 12 hours. The mortality and toxicological effects were observed for 30 h, at 6 h intervals. Important toxicological effects were observed on the larvae, such as lack of co-ordination, knock-down and paralysis followed by death, although the lethal capacity of the product after 30 h was low, with mean mortality of only 34%, 40.2%, 46% and 57.6% respectively, for the 0.5 ml/l; 1 ml/l; 2 ml/l/; and 3 ml/l dosages. There was no mortality in the control group. The results obtained did not indicate the use of this formulation, in the tested dosages, as a method of choice for R. sanguineus control.

Animals↗
PubMed1990

Acaricide resistance in single and multi-host ticks and strategies for control.

The majority of reports, concerning resistance in multi-host ticks, continue to be confined to the cyclodiene group and lindane, with sparse references to resistance affecting the organophosphorus acaricides. In contrast, the resistance picture in Boophilus spp., particularly in relation to B. microplus in Australia, continues to degenerate. Recent reports, documenting the emergence of a complex of pyrethroid resistant strains in the latter species, are the cause of considerable current concern, due to the lack of a suitable, commercially available, replacement group. These developments reinforce the need for a close examination of the strategies recommended for the management of acaricide resistance, particularly for Boophilus spp. The choice of options to select, in circumstances following the detection of resistance to an acaricide, is limited to those aimed at preserving the use of the affected chemical, or selection of an effective alternative, either from within the same class, or from a new acaricide group. Success of the former options, including tactics such as increased concentration or eradication of resistant alleles, and the rational choice of alternative acaricides for use in localized areas where necessary, are critically dependent on early detection of a newly emerged resistance mechanism, its localization, and an understanding of its spectrum of effect. Avermectins and acarine growth regulators show promise as potential future tick control agents. However, the dearth of new chemistry in this area stresses the importance of developing optimal strategies to extend the effective life of these and currently available compounds, in areas where they remain effective.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2002

Disaggregation of aggregated platelets by savignygrin, a alphaIIbeta3 antagonist from Ornithodoros savignyi.

Ticks control their host's hemostatic system by secretion of bioactive components during feeding that inhibit blood coagulation and platelet aggregation. Dissolution of platelets that have already aggregated can enhance control over the hemostatic system. It has been shown that disaggregation of aggregated platelets by the enzyme apyrase was accompanied by a shape change from the aggregated spherical form back to the discoid form associated with un-activated platelets. The present study concerns the disaggregation effect of the alpha IIb/beta3 antagonist, savignygrin. Aggregated platelets that were disaggregated by savignygrin and platelets pre-incubated with savignygrin before activation with ADP, retained a spherical form similar to platelets disaggregated by the fibrinogenolytic enzyme plasmin. The number of pseudopods were however, markedly reduced suggesting a disruption of the focal adhesion points that act as a localization point of alpha IIb/beta3. These results are concurrent with targeting of alpha IIb/beta3 and dissociation of fibrinogen from its receptor, once aggregation has taken place. This is the second mediator of platelet disaggregation found in soft ticks and suggests that disaggregation of aggregated platelets might play an important part in the anti-hemostatic strategy of ticks.

Animals↗
PubMed1997

Serological survey of heartwater relative to the distribution of the vector Amblyomma variegatum and other tick species in north Cameroon.

A study was carried out on the spatial and temporal distribution of Amblyomma variegatum and other ticks infesting sheep and goats in northern Cameroon. A serological survey of heartwater (cowdriosis) using a competitive ELISA was concurrently carried out in the same flocks. A. variegatum was found to be the most predominant species accounting for 48.3% of all the ticks collected. Other species identified included Rhipicephalus sulcatus, R. lunulatus, R. turanicus, Boophilus decoloratus, B. annulatus, Hyalomma nitidum and H. truncatum. Tick control was found to be necessary between June and December in the North and in the southern part of the Far North Provinces with annual rainfall average of 800 mm and above. Heartwater serology indicated that the disease appears to be endemic with a mean prevalence of antibodies to Cowdria ruminantium of 61-67%. Antibody prevalence was highly associated with the presence of A. variegatum (P < 0.001). Studies of the susceptibility of animals from Amblyomma-free areas to heartwater through natural exposure to the vector are envisaged.

Animals↗
PubMed1999

A double headed serine proteinase inhibitor--human plasma kallikrein and elastase inhibitor--from Boophilus microplus larvae.

Preying on cattle, the hard tick Boophilus microplus causes heavy economical losses to Brazil. Tick proteins are a good target to be used as tools for tick control. Serine protease inhibitors from B. microplus larvae (BmTI) were preliminarily characterized. One-week-old larvae were the source of a 2% protein solution in 5 mM Tris-HCl, 20 mM NaCl, pH 7.4. The inhibitors were purified by affinity chromatography on trypsin-Sepharose, and ion-exchange chromatography on Resource Q column, and they separated in two major active peaks, corresponding to 10-kDa and 18-kDa proteins (BmTI-B and BmTI-A, respectively). Both purified proteins inhibited trypsin with Ki of 0.3 and 3.0 nM, respectively, but only the 18-kDa protein inhibited elastase (Ki 1.4 nM) and plasma kallikrein (Ki 120 nM). BmTI-A did not change prothrombin time (PT) and thrombin time (TT), but it increased activated partial thromboplastin time (APTT) was dose-dependent. The partial amino acid sequence indicated that BmTI-A belongs to the bovine pancreatic trypsin inhibitor (BPTI)-Kunitz type inhibitor family. These inhibitors (by their properties) play a role in the feeding process of the tick. Development of antibodies against these proteins may be used to impair the normal feeding and consequently, the parasite would be no longer viable.

Amino Acid Sequence↗
PubMed1996

Effects of pyriproxyfen on engorged females and newly oviposited eggs of the lone star tick (Acari:Ixodidae).

Engorged females and 1- to 3-d-old eggs of the lone star tick, Amblyomma americanum (L), were exposed to 9 treatments of pyriproxyfen (4, 8, and 16 micrograms/cm2) in glass vials at exposure periods of 7 d, 14 d, and continuous at each dosage level. Treatment of newly engorged females did not affect the number of females ovipositing, but the number of eggs oviposited decreased as dosage and exposure time increased. Complete inhibition of egg hatch occurred at all treatment levels except that of the lowest dosage and exposure time where 99.9% inhibition was observed. Egg masses from treated females contained eggs that turned a dark amber color and imploded, retained normal shape and color without visible evidence of embryogenesis, or had developed embryos that were unable to emerge. Treatments of 1-to 3-d-old eggs were effective in reducing hatch and larval survivorship to 25 d after emergence only at the continuous exposures of dosages of 4, 8, and 16 micrograms/cm2. Larvae emerging from eggs treated at the lower dosage rates of 0.2 and 0.02 microgram/cm2 were as successful in feeding on chickens and subsequently molting as acetone treated control ticks.

Animals↗
PubMed1989

Influence of regular tick and helminth control on productivity of small ruminants in the Lolgorien area, Narok district, Kenya.

Forty-five indigenous goats (one to two years old) and 45 indigenous sheep (six to eight months old) were exposed to natural tick and gastro-intestinal parasite challenge. All animals were born and reared in a pastoral husbandry system. Throughout the study they were housed at night under improved hygienic conditions and grazed during daytime with the flock from which they originated. Improvement of hygienic conditions reduced mortality. Control of intestinal parasites increased liveweight gain (LWG) in both species and reduced mortality most noticeably in sheep. Regular tick control had a negative influence on LWG in goats over one year old but a positive influence on LWG on young sheep. This, however, was of marginal economic benefit compared to a substantial benefit of helminth control.

Animal Husbandry↗
PubMed2001

Seroprevalences of vector-transmitted infections of small-holder dairy cattle in coastal Kenya.

A cross-sectional study was carried out from July to September 1989 in Kaloleni Division, Coast Province, Kenya to estimate the prevalence of vector-transmitted diseases in small-holder dairy cattle and to identify the risk factors associated with different management systems. One hundred and thirty of the 157 herds with dairy cattle in Kaloleni Division were surveyed. These were from three agro-ecological zones (coconut-cassava, cashew nut-cassava and livestock-millet), comprised two management systems (stall-feeding and herded grazing) and were herds with either dairy cattle only or with Zebu and dairy cattle. A formal questionnaire sought answers to questions on cattle health and management practices. A total of 734 dairy and 205 Zebu cattle in 78 dairy and 52 mixed (dairy and Zebu) herds were sampled and screened for haemoparasites (Trypanosoma, Anaplasma, Babesia, and Theileria infections). Sera were tested for antibodies to Theileria parva, using the schizonts-antigen indirect fluorescent-antibody (IFA) test and to antibodies for Babesia bigemina and antigens to Anaplasma marginale by enzyme-linked immunosorbent assay (ELISA). Packed-cell volume (PCV) also was measured. Tick-control measures were practised by all except three of the farmers. Despite this, overall seroprevalence to T. parva was >70%--suggesting either that control practices were not strictly implemented or they were ineffective. The seroprevalence of T. parva in adult cattle kept in stall-feeding systems in the coconut-cassava zone was significantly lower (57+/-8% (S.E.)) than in herded-grazing systems (79+/-3%) and there was no association between antibody prevalence and age of cattle in this zone. Antibody prevalences in cattle in the cashew nut-cassava and the drier livestock-millet zone increased with age. Cattle in herded-grazing systems had an overall lower seroprevalence of T. parva infection in the livestock-millet zone (45+/-6%) than in the other two zones. Analysis was confined to the coconut-cassava zone for B. bigemina and to the coconut-cassava and cashew nut-cassava zones for A. marginale. Mean prevalences of B. bigemina were 40.9+/-9 and 73+/-6% for dairy cattle under stall-feeding and herded-grazing systems, respectively, and increased with age. Antigen prevalences of A. marginale were over 80% in all age groups of cattle in the coconut-cassava and cashew nut-cassava zones. Overall trypanosome prevalence in cattle was <1%. Trypanocidal treatment was uncommon. The variations in antibody prevalence associated with risk factors such as feeding system, agro-ecological zone and age of animal suggest that management system influenced exposure to tick-borne infection (particularly, T. parva infections) in small-holder dairy cattle in coastal Kenya.

Agriculture↗
PubMed1999

Toxicity of neem seed oil (Azadiracta indica) against the larvae of amblyomma variegatum a three-host tick in cattle.

The in vitro toxicity of neem seed oil (Azadiracta indica, family: Meliaceae, 'Dogon yaro' in Hausa -language) was tested against the larvae of a three-host tick, Amblyomma variegatum (family: Ixodidae or hard tick) parasitic to cattle commonly found in Nigeria. Undiluted neem oil (100% concentration) was found to kill all (100% mortality) the larvae after 48 h. The toxicity was concentration and time dependent.

Animals↗