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At least 19 recordsLinked to original sources

PubMed1992

Tick sweep: modification of the tick drag-flag method for sampling nymphs of the deer tick (Acari: Ixodidae).

We describe a version of the standard tick drag-flag modified for use in close-growing and tangled vegetation, as well as under ornamental shrubbery and fallen branches. Two major features of the sweep are: (1) it allows the user to remain upright with the flag parallel to the ground, thus sampling effectively beneath low and fallen branches and around shrubs, as well as capturing host-seeking ticks in advance of the operator; and (2) the use of a flannel rubberized-laminate fabric (crib sheet) for the flag that is snag-proof and highly durable in dense and thorny vegetation. In simultaneous 100-m samples, the sweep was as effective as the 1-m standard tick drag for capturing nymphs of the deer tick, Ixodes dammini Spielman, Clifford, Piesman & Corwin, where understory vegetation was sparse, but was twice as effective in dense vegetation, capturing significantly more I. dammini nymphs. The sweep also captured nymphs of the American dog tick, Dermacentor variabilis (Say); rabbit tick, Haemaphysalis leporispalustris (Packard); and lone star tick, Amblyomma americanum (L.).

Animals↗

PubMed1976

Reaction of the host to the tick-bite. II. Distribution of tick borne encephalitis virus in sucking ticks.

No reactive histological changes of the dermis and no cement cone formation were observed at the insertion site of tick mouthparts by feeding of H. inermis larvae. Conversely, cement formation was observed by feeding of H. inermis female. Fully fed D. marginatus larvae on viraemic mice showed bright fluorescence in oesophagus, suboesophageal ganglion, salivary glands, a few gut cells and in lumen of Malpighian tubuli. We consider the penetration of virus from oesophagus to suboesophageal ganglion as the possible route of primary virus infection. Sections through the D. reticulatus nymphs during virus transmission (38 hours after attachment) showed specific fluorescence in epidermis and gut cells. This finding is in agreement with the secretory activity of epidermial and gut cells during feeding.

Animals↗

PubMed1990

The effect of host resistance to tick infestation on the transmission of Thogoto virus by ticks.

Tick-borne virus transmission was examined using guinea-pigs and hamsters previously infested with ticks. Guinea-pigs developed immunity to Rhipicephalus appendiculatus after a single exposure to the ticks. Nymphal and adult stages that fed on resistant guinea-pigs had increased mortality during feeding, and reduced engorged weights. Egg production from female ticks fed on resistant hosts fell by at least 50%. Guinea-pigs maintained high levels of immunity to tick infestation for at least 210 days after the initial exposure. In contrast, hamsters did not develop resistance to ticks even after three or four infestations. R. appendiculatus adults infected with Thogoto (THO) virus (donors) were allowed to co-feed with uninfected nymphs (recipients) on either resistant or naive guinea-pigs. The number of recipient ticks that acquired virus was significantly reduced on resistant guinea-pigs. In contrast, feeding on pre-infested hamsters did not affect tick-borne transmission of THO virus. Host resistance to tick infestation, if prevalent in nature, may severely limit the spread of tick-borne viruses. Such an effect could result directly from a reduction in the number of ticks that acquire virus, or indirectly from poor egg production (in the case of viruses maintained in ticks by vertical transmission) and reduced survival of ticks fed on resistant hosts.

Animals↗

PubMed2025

Surveillance of tick-borne viruses in the border regions of the Tumen River Basin: Co-circulation in ticks and livestock.

BACKGROUND: The unique eco-geographical patterns and climatic conditions of the China-Tumen River border region, combined with frequent cross-border tourism and trade activities, collectively establish this area as a recognized hotspot for tick-borne disease outbreaks. However, critical knowledge gaps persist regarding the eco-epidemiology of emerging tick-borne viruses and the distribution of their potential reservoir hosts within this trinational ecosystem spanning China, North Korea, and Russia. METHODS: We collected a total of 2,004 ticks from the study area, along with blood samples obtained from 42 sheep and 45 cattle. Following viral metagenomic analysis of the ticks, dual verification of target pathogens in all samples was performed using qRT-PCR and RT-PCR assays. Phylogenetic trees were constructed and nucleotide sequences were analyzed to delineate relationships between the obtained virus strains and reference sequences. RESULTS: Viral metagenomics identified three viruses in ticks: Dabieshan tick virus (DBTV), Songling virus (SGLV), and Yanggou tick virus (YGTV). PCR analysis detected DBTV exclusively in Hunchun ticks (minimum infection rates, MIR:4.73%) and YGTV in Antu specimens (MIR:0.97%). Conversely, SGLV was detected in ticks from all four regions, with MIR of 1.68% (Helong), 0.74% (Hunchun), 1.61% (Antu), and 4.79% (Longjing). Concurrently, SGLV was detected in 19 sheep blood samples from Longjing, yielding a positivity rate of 45.24%, while YGTV was identified in 13 cattle blood samples from Antu, with a positivity rate of 28.89%. Phylogenetically, the DBTV strain clustered with previously reported DBTV and Yongjia tick virus 1 isolates. Sheep-derived SGLV strains shared close evolutionary ties with tick-borne SGLV, whereas YGTV from cattle and ticks formed a distinct cluster with Russian strains but diverged into two branches from Chinese variants, suggesting evolutionary instability. CONCLUSION: These findings address critical knowledge gaps in the transmission dynamics and genetic diversity of emerging arboviruses while providing vital insights for developing cross-border surveillance strategies with significant public health implications.

Animals↗

PubMed1991

Anti-tick saliva antibody: a biologic marker of tick exposure that is a risk factor for Lyme disease seropositivity.

Anti-tick saliva antibody (ATSA) has potential as a biologic marker of exposure to tick bites. In 1989, we conducted a cross-sectional study of 304 outdoor workers in Monmouth County, New Jersey, to evaluate associations between self-reported tick exposure, ATSA status, and Lyme disease antibody status. ATSA levels 1) were correlated with an index of tick exposure on the basis of three self-reported measures of tick exposure and outdoor hours worked per week (p = 0.01); 2) were consistently higher in pet owners compared with persons without pets (p = 0.03); and 3) when examined by duration since last tick bite, peaked at 3-5 weeks after tick bite and then declined (p = 0.06). ATSA levels dichotomized at the 75th percentile (approximately two standard deviations above the mean ATSA optical density of 25 subjects who denied recent tick exposure) were associated with self-reported tick exposure: adjusted odds ratios for high ATSA levels were 4.2 (95% confidence interval (CI) 0.9-18.9) for moderate (versus none) tick exposure and 5.8 (95% CI 1.2-27.2) for high (versus none) tick exposure. Finally, high ATSA levels were associated with Lyme disease seropositivity, with an adjusted odds ratio of 3.2 (95% CI 1.3-7.6). The data suggest that ATSA is a biologic marker of tick exposure that is a risk factor for Lyme disease seropositivity.

Adolescent↗

PubMed2026

Detection and phylogenetic characterization of Jingmen tick virus in Amblyomma mixtum ticks from Costa Rica.

UNLABELLED: Jingmenviruses are a group of segmented flaviviruses detected in arthropods and vertebrates that have attracted growing public health interest due to the recognition of some members as emerging human arboviral pathogens. As part of a study aimed at deciphering the virome of ticks of medical and veterinary importance in Costa Rica, we detected Jingmen tick virus (JMTV) in host-feeding Amblyomma mixtum ticks collected from horses. We assembled three complete genome segments and one partial segment from tick pools. Phylogenetic analyses revealed that JMTV from Costa Rica (JMTV Costa Rica) shares a common viral ancestor with JMTV viruses identified in ticks from the Caribbean and Latin America. Two distinct clades of Jingmenviruses were identified in the American continent, suggesting two distinct introductions: one from Europe/Asia and the other from Africa/Asia. Of note, JMTV Costa Rica falls in the same clade as viruses from Europe and Western Asia, including sequences found in humans. Our study constitutes the first detection of JMTV in Amblyomma mixtum. This tick species feeds on a wide range of hosts, including wildlife, domestic animals, and frequently parasitizes humans in Central America. Further research involving the detection of active and past infections by JMTV in humans and horses after tick bites is needed to evaluate the risk of spillover in Central America, including Costa Rica. IMPORTANCE: Jingmenviruses are flaviviruses detected in arthropods and vertebrates, reported in several countries worldwide. Some members cause disease and infections in humans; therefore, they are considered emergent human arboviruses. In Costa Rica and Central America, there is no information on tick-associated viruses or the role of ticks as putative vectors of viruses. Here, we report the first regional detection of Jingmen tick virus (JMTV) in Amblyomma mixtum ticks collected from horses. We assembled three complete and one partial viral segment from tick pools. Phylogenetic analysis revealed that the JMTV detected in Costa Rica is closely related to other detections from Latin America and the Caribbean and is located in the same clade as viruses reported in humans. Additionally, we detected two separate introductions of JMTV to Latin America. To determine whether this JMTV is an emergent arbovirus locally, research on past or active infections in humans is required.

Animals↗

PubMed1990

The impact of natural infestations of ticks in Zambia on the productivity of cattle and implications for tick control strategies in central Africa.

Studies were carried out in Zambia using a farming systems approach to quantify the effects of tick control on traditionally managed Sanga cattle. In the first trial to investigate the effect of tick control, significant improvements in liveweight gain (LWG) occurred only in periods of medium to high challenge with adult Amblyomma variegatum. However, during the first 18 months of the study when animals were young, the acaricide used caused a suppression in weight gains. A supplementary experimental study indicated that the adverse effects of ticks on weight gain may be delayed when animals are on a low plane of nutrition. In both studies on the effects of ticks on LWG, estimates of weight loss per female A. variegatum were in the range of 46 to 69 g. In the second long term trial to measure the impact of tick control on overall heard productivity, outputs of milk and weaner calf per livestock unit carrying capacity were about 25% higher in a tick-free herd. The annual cost of control in 1988 at ZK286.26/livestock unit was greater than the increase in value of the products at ZK175.48/livestock unit carrying capacity. It is concluded from these studies that intensive tick control in the multipurpose livestock system in Zambia is not justified in the absence of serious tick-borne disease. However, strategic seasonal tick control of adult ticks from November to April would probably be economically viable. Calves should not be treated until they are 3 months of age.

Africa, Central↗

PubMed1992

Probability models of the rate of infection with tick-borne encephalitis virus in Ixodes persulcatus ticks.

A total of 3,254 adults of Ixodes persulcatus tick were collected in a taiga forest habitat situated in the Amgun river basin (Khabarovsk region, the Far East, USSR) and examined individually for the presence and amount of tick-borne encephalitis virus. The over-all proportion of infected ticks was 6.6% and it varied between 3.4% and 9.4% in the years 1982 to 1985. The amount of virus per tick was approximated by the gamma distribution determining a probability that the number of plaque-forming units (PFU) per tick is not greater than a selected value. The frequency distribution of infected ticks followed a model of the negative binomial distribution, enabling the estimation of probability of the occurrence of a given number of infected ticks in the area. However, the parameters of both probability models (i.e., the PFU content per tick, and the frequency of infected ticks) varied for particular years.

Animals↗

PubMed1992

The role of host behaviour in tick-host interactions: a domestic host-paralysis tick model.

The aim of this study was to quantify the infestation densities of Karoo and brown paralysis ticks on sheep and goats and explain it in terms of the etho-ecology of these ticks and their domestic hosts. The Karoo paralysis tick usually quests from a vantage point on the vegetation whereas the brown paralysis tick displays an appetence response from the ground and mainly engages hosts that are prostrate. Both tick species are confined chiefly to hilly areas. Temporal differences in the infestation densities of the hosts within and between tick species were evident. These differences were related to disparities in the spatial distribution of the hosts, their activity patterns and the specific appetence responses of the two tick species. Differential climatological conditions affected the quality of forage in areas with a varied topography and the feeding preferences of hosts influenced tick-host sympatry and hence infestation densities.

Animals↗

PubMedDate not supplied

[The use of smells of plant origin as indicators of the extensiveness and intensity of ixodid tick infection with the tick-borne encephalitis virus].

It has been shown that, using a simple olfactometer, through which moist air and smell of vegetative origin penetrate into the centre via different ends of the tube, ticks can be divided into two groups, those infected and not infected with tick-borne encephalitis virus. The method yielding a 100% division, is based on opposite changes in the behaviour of virus infected ticks: the attracting smells become repellent and vice versa. Normal reaction to smell measured by the length of the distance covered by an individual tick towards or from the smell source in the olfactometer tube varies in various groups of control and experimental ticks, but correlates with virus titre of ticks. It is greater in ticks with a higher level of virus reproducibility. The reaction to smell in infected ticks makes it possible to predict the intensity of their infestation.

Animals↗

PubMedDate not supplied

[Effect of the physiological state of ticks on the intensity of tick-borne encephalitis virus replication in them].

The features of tick-borne encephalitis (TBE) virus reproduction in Ixodes ricinus and Dermacentor anderson ticks were studied in relation to the age of ticks, duration of fasting, feeding, and conditions of keeping the ticks before and after the experiment. Parenteral infection of ticks at various intervals after molting showed that the most favourable conditions for reproduction, survival, transphase and transovarial transmission of the virus occurred when the virus was given to the ticks in the first days after the period of postlarval development followed by feeding the vectors on vertebrates. In this case, owing to increased metabolic activity and intensive organogenesis and histogenesis, the virus persisted in ticks in high titers till the moment of oviposition and penetrated into the egg batch. When the virus was inoculated into old exhausted females (8-18 months) virus titers in ticks were low and penetration of the virus into the egg batch was irregular.

Animals↗

PubMed1990

Microwave fixation: in situ tick (Acari: Ixodidae) histoanatomy, thin sectioning of tick tissues, and antigen preservation in mouse spleen.

Microwave irradiation was used for the fixation of eggs, nymphs, and adult Boophilus spp. ticks. Although optimal temperatures for fixation of the different tick stages varied, heating to 58 degrees C of adult ticks submerged in either PBS or fixative was found to be sufficient. After microwave fixation, whole adult ticks, hand held, were sectioned with a sharp razor blade. The resulting sections revealed the in situ histoanatomy of the tick. Thin sections of ticks were obtained after either paraffin or polyester wax embedding. Microwave fixation combined with polyester wax embedding made serial thin sections of the different stages of Boophilus ticks possible. The technique preserved antigens as demonstrated by the immunostaining of lymphocytes and erythrocytes infected with Babesia microti in mouse tissues subjected to the same treatment as the ticks. With the microwave fixation-polyester wax technique, the specimen preparation time from fixation to the section on the glass slide was reduced to less than 8 h.

Animals↗

PubMed1992

The Alsatian tick-borne encephalitis focus: presence of the virus among ticks and small mammals.

An extensive epidemiologic survey was carried out from 1970 to 1974 in order to understand the condition of circulation of tick-borne encephalitis virus between ticks and small mammals in the Alsatian focus, France. The virus has been isolated from Ixodes ricinus adult ticks (30 lots out of 369, representing a total of 5617 ticks), and from Ixodes ricinus nymphs (4 lots out of 251, representing a total of 8587 ticks). The virus has also been isolated from 11 pools of rodent organs (out of 3361 rodents), and HI antibodies were detected in 21 out of 8735 rodent specimens. The virus has never been detected in rodent blood, nor in 10,298 ticks collected engorged from 1505 vertebrate hosts. These results show that Alsatian tick-borne encephalitis focus is stable since the activity of the virus is detected every year, and that the focus is an extended one since the virus is isolated from 5 of 6 study sites, as well as in several control sites.

Animals↗

PubMed1991

Tick (Acari: Ixodidae) infestations on Zebu cattle in western Kenya: seasonal dynamics of four species of ticks on traditionally managed cattle.

A study was conducted on the population dynamics of four tick species infesting livestock on Rusinga Island. Infestations of Rhipicephalus appendiculatus Neumann, Rhipicephalus evertsi evertsi Neumann, Amblyomma variegatum (F.)., and Boophilus decoloratus (Koch) were monitored on East African shorthorn Zebu cattle at monthly intervals for 2 yr. These cattle were of unimproved stock under traditional husbandry without any tick control practices. Most ticks were on cattle between September and March, with a peak in December-February. Following the onset of the rainy season in April, tick numbers on the cattle declined markedly; this decline continued until July or August, when numbers started to increase again. No significant correlation could be made between these population changes and any of the four climatic factors recorded. Instead, there was a notable relationship between tick population changes and local farming practice. The area and duration of cattle grazing activity were severely curtailed during the cropping season from April to September, which reduced tick-host contact and thus the tick burdens of the cattle at that time.

Animals↗

PubMedDate not supplied

[The effect of the physiological age of Dermacentor marginatus (Ixodidae) ticks on their infection with and the infiltration of the tick-borne encephalitis virus into the saliva].

The decisive effect of physiological age of ticks on the infection of their saliva was revealed by means of parenteral infection of D. marginatus females with tick-borne encephalitis virus. The virus was not found in the saliva of young individuals of instar II. Maximum number of cases of saliva infection was recorded in mature ticks of instar III (50%). It was established that the infection of saliva did not depend on the amount of virus in the tick's body. Less susceptibility to the virus of young individuals, associated probably with the way of infection, was noted. Under light microscopy there were observed no significant age differences in salivary glands of ticks of instars II and III. The infection of saliva of young individuals is, apparently, opposed by the barrier of fat body on the way of virus to salivary glands, depending on the age of ticks. The barrier is supposed to have an influence under natural transphase infection of ticks.

Animals↗

PubMed1976

Preliminary characterization and pathogenicity studies of a virus isolated from ticks (Ornithodoros coriaceus) and from tick-exposed cattle.

Several viral isolates from ticks (Ornithodoros coriaceus) and from the blood of cattle which aborted after exposure to these ticks were found to be identical by reciprocal cross serum-neutralization tests. Characterization studies indicate that the virus is a member of the Togaviridae family, although specific identification is still incomplete. Whether its natural host is the tick or bovine animals is also unknown. Pregnant cows inoculated with the agent by all conventional parenteral routes, including intrafetal, delivered healthy calves at term. It was concluded, therefore, that it was not a bovine pathogen and that the abortions which occurred after tick-exposure were due to a 2nd agent in O coriaceus ticks which also harbor the virus. While several ciruses believed to be tick-borne have been isolated from cattle in various parts of the world, it is believed that the present report describes the first isolation in the Western Hemisphere for a viral agent from Argasid ticks which has been demonstrated to replicate in cattle.

Abortion, Veterinary↗

PubMed1992

Cluster of tick-borne infections at Fort Chaffee, Arkansas: Rickettsiae and Borrelia burgdorferi in ixodid ticks.

Human intrusion into pristine habitats increases the likelihood of acquiring infectious agents from potentially infective ticks. As part of a larger human serological investigation into tick-borne illnesses, 3,000 ixodid ticks were collected during May, August, and November 1990 at Fort Chaffee, Arkansas. Ticks were examined to determine whether they harbor rickettsiae, ehrlichiae, and Borrelia burgdorferi, and to assess relationship to human exposure to tick-borne infections at Fort Chaffee, Ark. The overall tick infection rates with SFG rickettsiae, B. burgdorferi, and ehrlichiae were 4.8, 0.1, and 0.3%, respectively.

Animals↗

PubMed1978

Anti-tick grasses as the basis for developing practical tropical tick control packages.

Of six grass species analysed, Melinis minutiflora (molasses grass) showed the highest anti-tick deterrent properties while Andropogon gayanus (Gamba grass) exhibited the ability to maintain a defined, constantly low, initial host tick infection property and lengthy but low to moderate field tick population. It was concluded that Melinis minutiflora is a species which would best be used in a tick control package within a marginal tick zone while Andropogon gayanus has the advantage within an endemic tick zone.

Animals↗