Showing papers on "Tick published in 1983"
TL;DR: A review of the avian and medical entomological literature indicates that ticks and other ectoparasites may be strong determinants of nesting success and of nest structure and duration of use.
Abstract: Densely nesting Guanay Cormorants (Phalacrocorax bougainvillii), Peruvian Booby (Sula variegate), and Peruvian Brown Pelican (Pelecanus occidentalis thagus) deserted eggs and young in response to high densities of argasid ticks (Ornithodoros amblus). Alternative causes of desertion such as human disturbance, predation, disease, heat, and food shortage did not fit the evidence. Tick predators were less effective at controlling ticks than were frequent human harvestings of guano. A review of the avian and medical entomological literature indicates that ticks and other ectoparasites may be strong determinants of nesting success and of nest structure and duration of use.
189 citations
TL;DR: Evidence suggests that deer act as a reservoir of the disease and provide an overwintering mechanism for both spirochetes and adult ticks.
Abstract: Spirochetes believed to be the cause of Lyme disease were isolated from white-footed mice and white-tailed deer, the preferred natural hosts of Ixodes dammini, the tick vector. Evidence suggests that deer act as a reservoir of the disease and provide an overwintering mechanism for both spirochetes and adult ticks. Some tick larvae may acquire the spirochete by transovarial passage and the nymphal stage may transmit the disease to humans.
152 citations
TL;DR: The large variation in losses in liveweight per tick on these animals on the same pastures at different times suggests that differences in published estimates are frequently due to animal variation rather than to nutrition, cattle breed or environment.
Abstract: The effect of the tick Boophilus microplus on the liveweight of Bos indicus x B. tauvus steers was investigated using three levels of infestation during summer 1980, autumn-winter 1980 and summer 1981. Mean losses in liveweight per engorged female tick during each of the three periods were 0.72,0.47 and 1.52 gper tick respectively. The 1980 estimates were significantly lower (P < 0.05) than that in summer 1981, and the losses were independent of tick density. The loss per tick was unaffected by a supplement of molasses and urea in the autumn-winter period. Compensatory growth of those steers whose earlier growth was retarded by poor nutrition or ticks was investigated by keeping all the steers tick-free during spring. The previous medium and high tick groups gained 5-6 kg per animal more than the low group. Non-supplemented animals recovered all of their 14 kg disadvantage compared with the supplemented group. Mean tick survival rates varied from 9% in summer 1980 to 25% in autumn and 2% in summer 1981. They were reduced at higher densities but were unaffected by the nutritional supplement. The large variation in losses in liveweight per tick on these animals on the same pastures at different times suggests that differences in published estimates are frequently due to animal variation rather than to nutrition, cattle breed or environment. Economic thresholds were calculated for a range of effects of ticks and of chemical control costs. With a mean loss of 0.6 g per tick and 1983 dipping costs of $A1.35, the economic threshold is 158 ticks engorging per day per animal, assuming a kill of 97 %.
102 citations
66 citations
TL;DR: In this paper, the occurrence of larvae and nymphs of the tick Ixodes ricinus in populations of the lizards Lacerta agilis and L. vivipara was investigated.
Abstract: In this paper we provide quantitative information on the occurrence of larvae and nymphs of the tick Ixodes ricinus in populations of the lizards Lacerta agilis and L. vivipara. Levels of infestation were rather low, at least when compared with those of small mammals and sheep. Hence we suppose that lizards feed only a minor fraction of the total tick population.
61 citations
TL;DR: Pressurized sprays of 0.5% permethrin and 20% deet applied to clothing were compared for personal protection against natural populations of lone star ticks and American dog ticks in Oklahoma and Kentucky during May and June 1982.
Abstract: Pressurized sprays of 0.5% permethrin and 20% deet applied to clothing were compared for personal protection against natural populations of lone star ticks, Amblyomma americanum (L.), and American dog ticks, Dermacentor variabilis (Say), in Oklahoma and Kentucky during May and June 1982. A 1-min application of permethrin to the exterior surface of pants and shirt (or blouse) provided 100% protection against the attack of both species of ticks. Comparable applications of deet provided 85% protection against adults and nymphs of the lone star tick and 94% protection against adults of the American dog tick.
52 citations
Journal Article•
TL;DR: Clear patterns of seasonal abundance could be determined only for the spirurid stomach worm, Physocephalus sexalatus, and the sucking louse, Haematopinus phachoeri.
Abstract: A total of 38 warthog, Phacochoerus aethiopicus, shot on a farm in northern South West Africa/Namibia were examined for internal and external parasites at monthly intervals over a period of 13 months. They harboured cestodes, 9 nematode species, 6 ixodid tick species and 1 species each of an argasid tick, a flea, a louse and larvae of a dipteran fly. Clear patterns of seasonal abundance could be determined only for the spirurid stomach worm, Physocephalus sexalatus, and the sucking louse, Haematopinus phachoeri.
42 citations
TL;DR: H a anatolicum ticks from both locations produced fatal theileria infection in susceptible calves and were found infected with parasite masses similar to those seen in experimental infections with T annulata.
40 citations
TL;DR: Theileria annulata was experimentally transmitted to cattle on two occasions by the two-host tick Hyalomma marginatum rufipes, but since the immature stages of this species normally feed on birds, this tick is unlikely to be an important vector in the field.
31 citations
TL;DR: Introduction of tick-resistant cattle provided a more effective means of reducing the risk of babesiosis outbreaks and the economic implications of computer-simulated babesia bovis control alternatives should be analyzed.
30 citations
TL;DR: Blood basophil responses were quantified in guinea pigs sensitized by infestation with larval Rhipicephalus appendiculatus and nymphal and adult Ornithodoros tartakovskyi ticks, and in normal controls, indicating a greater host sensitivity to O. tartkovskyi salivary secretions, substances crucial to the feeding process.
Abstract: Blood basophil responses were quantified in guinea pigs sensitized by infestation with larval Rhipicephalus appendiculatus (ixodid) and nymphal and adult Ornithodoros tartakovskyi (argasid) ticks, and in normal controls. In addition, blood eosinophil responses were examined in hosts infested with larval R. appendiculatus. Hosts exposed to primary and secondary infestations with R. appendiculatus exhibited similar elevations in blood basophils up to day 3 of infestation, when levels were increased fourfold over control (uninfested) hosts. By day 4, basophil levels in primary hosts were reduced markedly, whereas in secondary hosts they were still increasing and peaked at a level nearly twice that of primary hosts and seven times normals. Blood eosinophils did not respond to primary tick feeding but exhibited a marked diphasic response to secondary tick infestation, peaking on days 2 and 5. Animals exposed twice to R. appendiculatus ticks exhibited acquired resistance when challenged, resulting in 5% tick yield compared to 27% tick yield from primary hosts. Guinea pig blood basophil responses to primary and secondary nymphal and primary adult O. tartakovskyi feedings were greater in intensity and occurred earlier than in animals parasitized by R. appendiculatus ticks. This finding indicates a greater host sensitivity to O. tartakovskyi salivary secretions, substances crucial to the feeding process. Basophil levels in primary and secondary hosts peaked on day 2 or 3, then remained elevated in primary hosts and fell rapidly in secondary hosts. Adult challenge feedings resulted in anamnestic-type blood basophil responses that were evident by 6 hours and yielded greater maximum elevations (nine times normal) than nymphal hosts (five times normal). O. tartakovskyi-sensitized animals failed to express acquired resistance when challenged with O. tartakovskyi or R. appendiculatus. Furthermore, there was no resistance to O. tartakovskyi even when a tertiary feeding occurred at the height of blood basophilia from a secondary feeding. Since these ticks probably ingested immune blood that contained basophils, it is unlikely that ingestion of sensitized basophils results in deleterious effects to these ticks.
TL;DR: Blood flow has been measured in bovine skin following the injection of tick antigens and a number of pharmacological mediators; including histamine, prostaglandins and slow reacting substance of anaphylaxis, which may influence blood flow during immune reactions to ticks and during the rapid ingestion of blood by the ticks.
Abstract: Blood flow has been measured in bovine skin following the injection of tick antigens and a number of pharmacological mediators; including histamine, prostaglandins and slow reacting substance of anaphylaxis. The greates increase in blood flow (20 times normal) was recorded with tick antigens and with prostaglandin F2. This mediator may therefore influence blood flow during immune reactions to ticks and during the rapid ingestion of blood by the ticks.
TL;DR: Studies of the seasonal activities of adult Dermacentor andersoni ticks were conducted in Larimer Co., Colorado, USA, during the summers of 1979–1980, indicating that ticks infected as larvae or nymphs retain the infection for extended periods.
Abstract: Studies of the seasonal activities of adult Dermacentor andersoni ticks were conducted in Larimer Co., Colorado, USA, during the summers of 1979–1980. Twenty-five CO2 platform traps were used in an 80 × 80-m grid to monitor hostseeking activities. Ticks were marked with a spot of fluorescent paint as they were captured in 1979, with a different color used for each month. Eleven percent of the marked ticks were recaptured the following summer. Using the Lincoln Index to determine population density by the mark-recapture method, we obtained an estimate of 1139 ticks per hectare for May 1979. In both years tick activity began in early March, peaked in late April, and virtually ceased by the end of June. The actual CTF infection rate of painted ticks surviving at least 2 winters in hibernation was 129 per 1000, indicating that ticks infected as larvae or nymphs retain the infection for extended periods.
TL;DR: The tick infestation of introduced cattle decreased markedly from day 368 and infestation had virtually ceased by day 808, and Lethal challenge levels of T. parva for cattle existed in the paddock up to day 547 after repletion, after which introduced cattle showed no infection or only a sub-lethal infection.
Abstract: A 2 hectare paddock on the Muguga Estate, Kiambu District of Kenya (altitude 2100 m) free of Theileria parva-infected ticks was seeded by applying Rhipicephalus appendiculatus nymphs to cattle infected with Theileria parva (Kiambu 4). It was estimated that over 50 000 engorged nymphs fell onto the pasture from 4 cattle with high parasitaemias during the cold season (June). Samples of these ticks were placed in plastic cylinders under the vegetation in the paddock and sexual stages of T. parva were detected in gut lumen smears in these samples up to 21 days after repletion. Zygotes were first observed to transform into kinetes on day 55 and parasites were first detected in salivary glands of adults on day 64. Moulting of the nymphs started on day 60 after repletion and was completed by day 87. Cattle introduced into the paddock showed their first infestation with adult R. appendiculatus on day 64 after repletion of the nymphs and the infestation level gradually increased. On day 76 after repletion, 17% of a sample of adult ticks infesting cattle showed salivary gland infections with T. parva and this increased to over 70% by day 150. From day 360 onwards, a decrease in both the percentage of ticks infected and the number of salivary gland acini infected/tick was noted. In addition, T. parva infections within the salivary glands required a longer period of feeding in the older ticks before they developed into sporozoites. Cycling of Theileria through ticks was prevented by the removal of female ticks before they completed repletion. Lethal challenge levels of T. parva for cattle existed in the paddock up to day 547 after repletion, after which introduced cattle showed no infection or only a sub-lethal infection. Cattle introduced into the paddock on day 808 after repletion showed no evidence of T. parva infection. The tick infestation of introduced cattle decreased markedly from day 368 and infestation had virtually ceased by day 808.
TL;DR: Unfed nymphs of the Australian reptile tick species Aponomma hydrosauri and Amblyomma limbatum stayed in aggregated groups in one spot, despite the presence of host lizards as close as 50 cm.
Abstract: Unfed nymphs ofthe Australian reptile tick species Aponomma hydrosauri and Amblyomma limbatum stayed in aggregated groups in one spot, despite the presence of host lizards as close as 50 cm. The two tick species apparently wait for hosts to come by, in contrast to other species which actively respond to nearby hosts. It may be that, because the bodies ofthe reptile hosts are so close to the ground, the ticks do not have to give up the benefits of remaining in sheltered microhabitats for efficient host finding.
TL;DR: Beagles have been immunised against the paralysing effects of the Australian paralysis tick Ixodes holycyclus by allowing female ticks to feed on these dogs, and complete immunity to the toxic effects of lethal numbers of feeding ticks has persisted in these beagles for at at least 53 weeks and in similarly-immunised foxhounds for at least 102 weeks, during which periods the beagles and Foxhounds were kept free of ticks.
Abstract: SUMMARY Beagles have been immunised against the paralysing effects of the Australian paralysis tick Ixodes holycyclus by allowing female ticks to feed on these dogs. Complete immunity to the toxic effects of lethal numbers of feeding ticks has persisted in these beagles for at least 53 weeks and in similarly-immunised foxhounds for at least 102 weeks, during which periods the beagles and foxhounds were kept free of ticks.
Serum antitoxin titres increased to a maximum value (hyperimmunity) of 46 antitoxin units/mL with a minimum number of 11 ticks feeding simultaneously. Titres declined to a low level after 12 to 14 weeks of freedom from tick infestation but increased again on reinfestation with ticks. Large numbers of ticks (up to 60) appeared to be required after several stimulation/relaxation cycles to obtain hyperimmune levels of antitoxin in serum.
The serum antitoxin titre appeared to be a good indicator of effective immunity to tick paralysis during the initial development of hyperimmunity but was less indicative thereafter, as dogs whose serum antitoxin titres had reached an apparent maximum remained immune to tick paralysis after titres had decreased to low levels. There was no evidence of cutaneous hypersensitivity or any other tick rejection mechanism that could account for this effect.
TL;DR: Pure strains of BabesIA bovis, Babesia bigemina and Anaplasma marginale were isolated from cattle infected with all 3 species as well as Theileria sp.
Journal Article•
TL;DR: Serological tests have recently indicated that there are antigenic differences between 'suburban' and 'bushveld' strains; these clearly require further study.
Abstract: Tick-bite fever, the variety of tick typhus occurring in southern Africa, is caused by Rickettsia conori var pijperi and is transmitted by hard or ixodid ticks It is usually a mild disease, especially in children and young adults, but in middle-aged and elderly patients (and sometimes in young adults) it may assume a severe form This is characterized by high fever, severe headache, delirium, stupor and occasionally coma, and a profuse maculopapular rash which becomes haemorrhagic and is associated with petechiae in the skin and later, but rarely, by the development of gangrene of the fingers and toes During these severe attacks the central nervous system may be involved and marked disorders of liver and kidney function sometimes lead to kidney failure and the need for treatment and dialysis in an intensive care unit Three illustrative cases are described in which diagnosis was delayed One patient died; 2 patients responded to administration of tetracycline The danger of allowing tick-infested dogs onto one's bed is stressed Infections transmitted by dog ticks tend to be more severe than those acquired via ticks from the bushveld, possibly because they so often occur in middle-aged and elderly patients Serological tests have recently indicated that there are antigenic differences between 'suburban' and 'bushveld' strains; these clearly require further study
TL;DR: Fly larvae were found feeding inside dead ticks and on fungi that accumulated in tick containers, causing problems associated with the effects of this fly on tick rearing.
Abstract: Larvae of Megaselia scalaris (Diptera: Phoridae) were found infesting a laboratory colony of Amblyomma variegatum in May and June 1981 and a laboratory colony of Anocentor nitens in October 1981. Fly larvae were found feeding inside dead ticks and on fungi that accumulated in tick containers. Problems associated with the effects of this fly on tick rearing and some possible solutions to these problems are discussed.
TL;DR: Detmacentor andersoni nymphs were readily infected by in vitro feeding on Anaplasma marginale -infected blood and transmitted the parasite during the adult stage and probable reasons for failure to transmit anaplasmosis are discussed.
Abstract: Procedures and apparatus for in vitro feeding of adult and nymphal stages of the ixodid tick Dermacentor andersoni are described. After prefeeding for 4 to 6 days on rabbits, both stages of the tick completed engorgement in artificial feeding devices using rabbit or mouse skin as the attachment surface and packed bovine red blood cells (RBC) as food. Nymphs completed engorgement during 2 days using a single mouse skin for attachment and 6 aliquots of packed RBC as food. Adult females in the presence of males reattached to rabbit skin 2 to 4 times during a 2- to 4-day period and completed engorgement. The residual RBC (and tick saliva) in the feeding device after artificial feeding of Anaplasma marginale -infected adult ticks was not infectious when inoculated into susceptible calves. Probable reasons for failure to transmit anaplasmosis are discussed. Detmacentor andersoni nymphs were readily infected by in vitro feeding on Anaplasma marginale -infected blood and transmitted the parasite during the adult stage.
Journal Article•
TL;DR: The 277F spiroplasma, while initially recovered from a pool of rabbit ticks (H. leporispalustris), is related by certain serological and genetic properties to spiro plasmas in the S. citri complex (serogroup I), suggesting that the 277F may not be a natural inhabitant of the rabbit tick.
Abstract: Three serologically distinct groups of spiroplasmas have been recovered from ticks. Spiroplasma mirum strains (from rabbit ticks, Haemaphysalis leporispalustris) and Y32 group (VI) spiroplasmas (from Ixodes pacificus) are the only spiroplasmas to have a clear association with these arthropods. Group (VI) spiroplasmas are distinguished by an unusual nonhelical morphology and their capacity to hemadsorb guinea pig erythrocytes. S. mirum strains are unique in their ability to induce cataracts or lethal brain infections in a number of young vertebrates and in their virulence for the chick embryo. The 277F spiroplasma, while initially recovered from a pool of rabbit ticks (H. leporispalustris), is related by certain serological and genetic properties to spiroplasmas in the S. citri complex (serogroup I). These relationships suggest that the 277F spiroplasma may not be a natural inhabitant of the rabbit tick.
TL;DR: It is hoped that the model presented will show the potential of formulating a system for predicting tick activity and could be used to enhance the control of tick-transmitted diseases.
TL;DR: Serologic results support clinical histories of human RMSF cases, and combined with tick-infectivity data suggest continued rickettsial activity in this ecosystem.
Abstract: Ticks and wild mammals were collected in 1980 and 1981 from Newtown, Connecticut, USA, an area where 6 persons probably acquired Rocky Mountain spotted fever (RMSF) during 1978–1981. Dermacentor variabilis , the American dog tick, parasitized a variety of small and medium-sized mammals but was most prevalent on White-footed Mice and Raccoons. It was the only tick found infected with hemocyte-associated, rickettsia-like organisms; of the 347 adults removed from hosts during 1980–1981, 50 (14.4%) were positive by the hemolymph test. Direct immunofluorescence tests confirmed spotted-fever group (SFG) rickettsiae in 16 (4.6%) specimens. The following mammals contained antibodies to SFG rickettsiae: Eastern Chipmunks, Gray Squirrels, Meadow Voles, Virginia Opossums, Raccoons, a Short-tailed Shrew, Striped Skunks, White-footed Mice, Woodchucks, and Woodland Jumping Mice. Serologic results support clinical histories of human RMSF cases, and combined with tick-infectivity data suggest continued rickettsial activity in this ecosystem.
TL;DR: Regression analyses showed that numbers of ticks attracted to human subjects could be predicted from CO2 densities with an acceptable level of precision and an economic threshold of 0.65 ticks per l-h CO2 sample was suggested for general use in tick management for recreational areas.
Abstract: A relationship between CO2 (dry ice) and human subject attraction of free-living adults and nymphs of Amblyomma americanum (L.) was studied in upland oak-hickory habitat in LeFlore County, Okla., during April to June 1981. Correlation coefficients of 0.75 to 0.90 (significant at P = 0.01) were obtained from analyses of numbers of ticks attracted to CO2 and human subjects at the same sampling sites, but on different days. Regression analyses showed that numbers of ticks attracted to human subjects could be predicted from CO2 densities with an acceptable level of precision. Economic threshold (CO2 densities) were then calculated from regression equation data for an eight-fold range of selected tick attack rates. An economic threshold of 0.65 ticks per l-h CO2 sample was suggested for general use in tick management for recreational areas.
TL;DR: It was shown that animals in shaded yards during daylight hours were more susceptible to ticks than animals in open yards, and areas of skin with the coat clipped carried fewer ticks than the corresponding unclipped area, irrespective of the location of the animals.
Abstract: Tick resistance and rectal (Tre) and skin (T5) temperatures were studied in male cattle of the breeds Hereford × Shorthorn (HS), Africander × HS (AX), Brahman × HS (BX), and Brahman (B). In 1 experiment, AX and HS animals were tick infested over 70 days. Tre showed diurnal variations but were higher in HS than in AX animals. The total number of mature ticks carried was lower on AX than on HS and was correlated ( r = 0.733) with Tre of the animals before infestation. Regressions of body weight gains on tick numbers were different between breeds, and expressed as kilograms/100 ticks were: HS, −1.06; AX, −0.36. In a 2nd experiment, Tre and T5 were different between HS, BX, and B breeds, and for each of the breeds it was shown that (1) animals in shaded yards during daylight hours were more susceptible to ticks than animals in open yards, and (2) areas of skin with the coat clipped carried fewer ticks than the corresponding unclipped area, irrespective of the location of the animals. The results suggest that T5 is more important than Tre in explaining part of the seasonal variations in susceptibility of cattle to ticks.
TL;DR: The tick loads and tick species infesting an experimental herd, a Rendille pastoralists' herd and two ranch herds of camels, in four different areas of Kenya are described.
Abstract: The tick loads and tick species infesting an experimental herd, a Rendille pastoralists' herd and two ranch herds of camels, in four different areas of Kenya are described. The tick species most commonly observed were Hyalomma rufipes, Hyalomma dromedarii and Rhipicephalus pulchellus.
TL;DR: Ticks were active on vegetation and on animals throughout the year, and tick population was highest on pasture during the dry months and least during the period of heavy rainfall.
Abstract: During a two-year study on the tick activity on experimentally and naturally infested pastures in a town in the forest zone of Nigeria, the following observations were made: (1) Ticks were active on vegetation and on animals throughout the year; (2) The larvae of Amblyomma variegatum (Fabricius), Boophilus decoloratus (Canestrini), Hyalomma marginatum rufipes (Koch) and Hyalomma truncatum (Koch) showed bimodal activity with almost equal peaks during the early and late dry months while the larvae of B. geigyi showed unimodal activity with a peak during the early rains. Adults of A. variegatum showed unimodal activity and those of Hyalomma species bimodal; (3) Tick population was highest on pasture during the dry months and least during the period of heavy rainfall. Larvae were predominant in numbers during each of the months; (4) Greatest numbers of ticks were obtained from pasture during the mid-afternoon sampling, at which time temperature was high and humidity was low; (5) There was correlation...