Showing papers on "Tick published in 1977"

The brown dog tick Rhipicephalus sanguineus and the dog as experimental hosts of Ehrlichia canis.

Abstract: Adult Rhipicephalus sanguineus ticks efficiently transmitted Ehrlichia canis to susceptible dogs for 155 days after detachment as engorged nymphs from a dog in the acute phase of ehrlichiosis. Adult ticks that had similarly engorged on a dog in the chronic phase of ehrlichiosis failed to transmit E canis to susceptible dogs. Infected but unfed adult ticks may be of greater importance than the chronically infected carrier dog as a natural reservoir of E canis.

Acquired resistance to ticks. iii. Cobra venom factor and the resistance response.

Abstract: Guinea-pigs developed resistance to larvae of the ixodid tick, Dermacentor andersoni, after one infestation. Resistant hosts were characterized by allowing significantly fewer larvae to engorge than non-resistant hosts. Larvae engorging on non-resistant hosts had a mean weight six times that of larvae obtained from resistant hosts at the end of a 5-day infestation. This immunologically based resistance was previously shown to have a cell-mediated and a humoral component. In an attempt to ascertain the role of complement in the resistance response, cobra venom factor (CoF) was administered to guinea-pigs producing prolonged (85--95 per cent) depletion of complement titres. CoF was administered during an initial infestation with tick larvae to determine if complement depletion altered the acquisition of tick resistance. CoF was also administered to tick-resistant hosts in an attempt to determine if the expression of tick resistance and the development of the basophil-packed lesion, characteristic of the tick-attachment site in resistant hosts, could be altered by complement depletion. CoF did not alter the acquisition of resistance when complement levels were reduced during a primary infestation. However, complement depletion of an animal which had acquired tick resistance blocked the expression of that resistance during a challenge infestation. In addition to increased numbers and weights of larvae engorging on tick-resistant animals depleted of complement, the basophil packed lesion at the tick attachment site was greatly reduced. Complement plays an important role in the expression of tick resistance in guinea-pigs.

East Coast fever: some recent research in East Africa.

Abstract: Publisher Summary East Coast fever (ECF) is a disease of cattle with considerable economic significance in the development of livestock industry in eastern Africa. The disease is a syndrome resulting from the infection of cattle by one or several of the protozoan parasites of the family Theileriidae, indigenous to eastern Africa. It is almost invariably fatal, high-grade cattle being particularly susceptible. The three parasites that, separately or in combination, are responsible for ECF in East Africa are all members of the genus Theileria. The chapter presents the development of three parasites—namely, Theileria parva (T. parva), Theileria lawrencei (T. lawrencei), and Theileria mutans (T. mutans)—in the tick vectors. It describes the techniques for infecting ticks and for harvesting parasites from them. The life-cycle of T.parva in the bovine host is discussed. Because it appeared that the parasites could not be attenuated by irradiating them either in their tick vector or when they were in free suspension, attention was turned to the possibility of suppressing the parasite after its introduction into a susceptible host. Some success had been achieved in this respect by feeding infected ticks in ear-bags on the animals and by daily oral administration of chlortetracycline hydrochloride or oxytetracycline hydrochloride for 28 days after infestation. In parallel with the development of the infection and chemoprophylaxis method of vaccination, studies have continued on the possibility of producing a tissue culture vaccine against ECF. Such a vaccine might well be more acceptable because it would be safer and easier to administer.

Ecological studies of ixodid ticks (Acari: Ixodidae) in Zambia. III. Seasonal activity and attachment sites on cattle, with notes on other hosts

Abstract: The seasonal activity of the adults of 13 tick species was studied on cattle herds in the Central Province of Zambia from 1969 to 1972. The six main species, Boophilus decoloratus (Koch), Hyalomma marginatum rufipes Koch, H. truncatum Koch, Amblyomma variegatum (F.), Rhipicephalus appendiculatus Neum., and R. evertsi Neum. behaved as previously described for the Southern Province. R. compositus Neum. appeared from August, with peak numbers in September–October. R. simus Koch and R. tricuspis Don. appeared from October, for seven months and three months respectively. R. supertritus Neum. and Ixodes cavipalpus Nutt. & Warb. had a brief activity season from November to January, and R. pravus gp. and R. sanguineus gp. were active from December to July. The distribution of ticks over the body of cattle was determined by fractionised collections, which gave reliable quantitative information for nine of the species. A limited number of collections from sheep, goats and dogs are analysed in relation to season. Collections from 127 wild animals, mainly along the escarpment and riverine bush of the Zambesi, are recorded.

Laboratory-acquired Rocky Mountain spotted fever. The hazard of aerosol transmission.

Abstract: Nine patients with laboratory-acquired Rocky Mountain spotted fever were seen during the period 1971 to 1976. Investigation of each case revealed either definite or probable exposure to an aerosol containing infectious rickettsiae; in no case was there evidence of parenteral exposure either by accidental self-inoculation or by tick bite. These illnesses are believed to represent infection acquired via the respiratory route. This report emphasizes the aerosol hazard of Rickettsia rickettsii in the laboratory and discusses the possibility of respiratory transmission of Rocky Mountain spotted fever in nature. The illness occurred only in personnel who had received either no vaccination or the primary series of the commercial (Lederie) vaccine against this infection. Other personnel who had received the primary series with multiple booster vaccinations demonstrated increased immunity as measured by humoral antibody titers and rickettsial antigen-induced lymphocyte transformation; no cases of clinical disease developed in these multiply-vaccinated personnel.

Infective Theileria annulata in the tick without a blood meal stimulus.

Abstract: THE agent of bovine tropical theileriosis, Theileria annulata, occurs in southern Europe, North Africa and most of Asia. The disease causes high mortality and reduced yield of meat and milk in the survivors. In enzootic areas theileriosis prevents the introduction of improved stock which are in most cases very susceptible. The work described here is part of a programme for improving the effectiveness of the vaccines now used for partial control of the disease. Theileriosis is transmitted in nature mainly by adult ticks that acquire their infection in the preimaginal stages. Adults become infective after feeding for a minimum of 2 d either on the susceptible bovine host or on a non-susceptible mammal like the rabbit1. As parasites can already be seen in the salivary glands of unfed adult ticks that are not infective2,3, it has been assumed that a blood meal provides the biological stimulus for the development of infectivity. In attempting to determine the factors other than feeding, that might stimulate the production of infective stage(s) of T. annulata, I have found that a temperature of 37 °C and a relative humidity (RH) of 95% is in itself sufficient to stimulate the production of infective parasite forms in infected adult Hyalomma excavatum ticks without the need for a blood meal.

The clinical features of tick bite.

Abstract: The clinical features of bites by the Australian scrub tick, Ixodes holocyclus, are reviewed. Eight cases of tick bite are summarized, including six new cases of tick paralysis in children. In almost all cases neuroparalysis became worse transiently, after the tick had been removed. One child with life-threatening respiratory and bulbar palsy received canine antitick antivenene, with rapid reversal of clinical signs. The differential diagnosis of tick bite includes all acute childhood diseases which can affect the motor units; the importance of including the possibility of tick envenomation in the differential diagnosis of acute weakness or paralysis in children is illustrated. The clinical features of neuromuscular paralysis are described, together with a review of the tick's local effects at the bite site.

Paralysis of calves by the tick, Ixodes Holocyclus.

Abstract: Adult female Ixodes holocyclus were collected from the field at Fig Tree Pocket, a Brisbane suburb, at Tamborine Mountain, Queensland and at Lismore, New South Wales, in November 1974. Females were also reared from engorged nymphs collected off bandicoots from Tamborine Mountain July 1974 and 1975. In November 1974 unexposed 2-3 week old British breed calves, weighing between 26 and 46 kg were infested with 2,4,8 or 10 ticks. Neither 2 nor 4 females per calf caused paralysis. A challenge of 8 to 10 females induced paralysis 6 to 9 days after infestation by which time most ticks had engorged. There was little difference between ticks from different geographic localities. The site of attachment had no influence on tick toxicity. In September 1975, 2-3 week old British breed and Sahiwal x Jersey calves were infested with female ticks which had moulted 2-4 weeks prior to infestation. All but one calf with 10 ticks and all calves with 4 ticks became paralysed 8 to 13 days after infestation. At the time of paralysis only 1 of the 86 ticks had engorged and the remainder were small (30 to 50 mg). The greater toxicity of the latter ticks may have been due to the different treatment of ticks prior to infestation or to variations in the production of toxin associated with slow feeding. Four of 7 paralysed calves were saved using canine antitick serum.

Rocky Mountain Spotted Fever in Childhood

Abstract: • Experience with 138 cases of Rocky Mountain spotted fever indicates that the major clinical features of characteristic rash, fever, and tick bite, in combination with low serum sodium concentration and thrombocytopenia, are helpful in recognizing this serious and potentially lethal infectious disease. (Am J Dis Child131:1228-1232, 1977)

Relationship of the occurrence and function of 2,6-dichlorophenol in two species of Amblyomma (Acari: Ixodidae).

Abstract: Female Amblyomma americanum (Linnaeus) and A. maculatum Koch ticks contained approximately equal and maximum amounts of 2,6-dichlorophenol at 16 days after emergence. A. maculatum males also contained substantial amounts of the compound, but only traces of the chemical were detected in A. americanum males. There appeared to be no increase in the 2,6-dichlorophenol content of feeding ticks. Only male ticks of both species were attracted to local applications of the phenol. No behavioral response was observed in A. maculatum females to explain the presence of 2,6-dichlorophenol in males of this species or elucidate other investigators' observations on the aggregation of the sexes of this tick on hosts.

Ixodes lividus (Acari) in sand martin colonies in Fennoscandia

Abstract: In sand martin colonies in southern and eastern Finland, about 15% of the adult birds were infested with Ixodes lividus Koch in the early phases of nesting. *During the nestling period, the infestation of adult birds dropped (< 10% infested), but the percentage of nestlings infested was 30. Of the juvenile birds, about 20% carried ticks. Adult birds were mainly infested with tick larvae and nymphs, whereas the nestlings and juveniles chiefly carried adult female ticks. Adult male ticks were found only in nests. The localization of the tick stages on the host's body was different in adults from that in nestlings and juveniles. All the tick stages were found in nests of sand martins in autumn and spring. It is concluded that the life cycle of I. lividus in Finland lasts more than one year. No virus isolates were obtained in assays with blood from infested birds, and with ticks from sand martin nests, but antibody surveys suggested that an agent of the Uukuniemi sero-group was present in the most heavily infested colony studied in southern Finland.

Seasonal Abundance of Lone Star Ticks on White-tailed Deer

Abstract: Peak infestations of adult Amblyomma americanum (L.) ticks on white-tailed deer [ Odocoileus virginanus (Boddaert)] occurred in late May, June and early July in 1973 and 1974. Significant nymphal tick infestations were observed from April to October. Peak larval tick infestations occurred in late July and August. The dynamics of the infestation levels were affected by climatic conditions and deer numbers. Repression of repletion of the adult and nymphal tick stages, apparently a response to photoperiod, has survival value in that the subsequent stage after molt does not become an active host-seeker at a time unfavorable for its maximum survival.

Uukuniemi group viruses isolated in Norway.

Abstract: As part of an ecological approach to the question of arboviruses in Norway, ticks(Ixodes ricinus, I. trianguliceps andI. uriae), small mammals and passerine birds were collected from selected localities along the coastal parts of the country in 1973. Some tick collections also were received from ornithological stations. Three Uukuniemi (UUK) virus strains were isolated from the tick material. The ticks yielding viruses originated from three very different biocoenoses. One isolate was made from engorgedI. ricinus nymphs picked up from migrant birds in the spring (SF E1). Another isolate (By E50) was made from unengorgedI. ricinus nymphs collected within an earlier established tick-borne encephalitis (TBE) virus focus. These two strains seemed serologically identical, and also identical to the Finnish prototype strain S23. The third isolate (Ru E82) was made from unengorgedI. uriae collected in a Common Puffin (Fratercula arctica) colony. Although clearly belonging to the UUK group of viruses, this strain demonstrated biological as well as antigenic differences to the other isolates. Some characteristics of the Norwegian UUK viruses are discussed in this paper. An immunoelectroosmophoresis method was used to screen human, bovine, small mammal and passerine bird sera for antibodies against the UUK isolate By E50. The results indicated that UUK virus (es) are wide-spread in the Norwegian coastal areas invaded byI. ricinus. The presence of mixed virus foci of UUK and TBE were indicated.

Ectoparasites Associated with Neotropical Turtles of the Genus Callopsis (Testudines, Emydidae, Batagurinae)

Abstract: Four species of Ambylomma ticks and a Placobdella leech were found in association with the turtle genus Callopsis. New host records are listed. Differences between attachment sites of the various tick life stages exist, and the ecological significance of these are discussed. LITTLE IS KNOWN of the ectoparasites of tropical turtles, and most available literature consists only of lists of parasites and their hosts. In 1973 the senior author began a systematic review of the neotropical emydid turtle genus Callopsis Gray.1 Many of the turtles examined still had ticks, and in one case a leech attached, which presented an opportunity to study the relationships between these parasites and their turtle hosts. The position of the parasites on the turtle and any apparent damage was noted. The parasites were removed, identified, and, in the case of ticks, sexed and staged. A list, with locality data, of ticks collected from each species of Callopsis is given in table 1. Most of the ticks have been deposited in the U.S. Public Health Service's Rocky Mountain Laboratory (RML 66172-66232), but some were returned to the herpetology departments of the Florida State Museum and Carnegie Museum. The leech was retained by the authors.

Nosema parkeri sp. n., a Microsporidan from the Argasid Tick, Ornithodoros parkeri Cooley

Abstract: SYNOPSIS. Nosema parkeri sp. n. is described from nymphs and adults of the argasid tick, Ornithodoros parkeri Cooley, from a laboratory colony. Schizogonic and sporogonic stages are described from various tick tissues. Spores are binucleate, measuring 3.2 (3–4) × 1.9 (1.8–2.5) μm. Transmission is transovarial and transstadial. The parasite does not appear to affect adversely the development or reproduction of the tick. Dermacentor andersoni Stiles was experimentally infected. Attempts to infect Swiss mice by tick feeding or by injection of infected tick suspensions were unsuccessful. The microsporidan differs in structure from Encephalitozoon ixodis Weiser) and Nosema slovaca Weiser & Rehacek, the only other microsporidans known from ticks.

Establishment of an experimental field population of Theileria lawrencei-infected ticks maintained by African buffalo (Syncerus Caffer).

Abstract: A population of Rhipicephalus appendiculatus ticks infected with buffalo-derived Theileria lawrencei was established in a paddock. Two infected buffalo had been introduced into this paddock which contained a small population of Theileria-free R. appendiculatus. At intervals, successive groups of Theileria-susceptible cattle were grazed with the buffalo. Transmission of T. lawrencei from buffalo to cattle was first noted 7 to 8 months after the introduction of the buffalo, this delay being accounted for by the slow buildup of the tick population and low infection rates in ticks. A T. lawrencei challenge lethal for cattle was finally achieved 10 months after the introduction of the buffalo. The paddock was then seeded with engorged R. appendiculatus female ticks and an increase in tick population occurred. The lethal challenge was observed for a further 3 years, death of exposed cattle becoming progressively more rapid as the tick population increased. The T. lawrencei challenge establsihed in the paddock may be suitable for testing the efficacy of various T. lawrencei-immunization procedures for cattle.

Some effects of a tick infestation (Haemaphysalis longicornis) on sheep

Abstract: Weight gain, wool production, packed cell volume, and haemoglobin levels (“tick effects„) were reduced in undipped 2-tooth ewes exposed to a naturally acquired infestation of the tick, Haemaphysalis longicornis. Mean adult tick counts reached a maximum of 27.8 per undipped sheep, the “tick effects” being evident on the 16th and 35th days following this peak. Mean tick counts on a control group of dipped animals were less than two per sheep.

Transmission of a Theileria species to cattle by the ixodid tick, Amblyomma cohaerens Donitz 1909.

Abstract: Amblyomma cohaerens nymphs, which had been collected as engorged larvae from African buffalo(Syncerus caffer) in the Mara region of Kenya, transmitted a theilerial parasite to a steer Macroschizonts were detected in the regional lymph node of this steer 12 days after tick application and were subsequently detected for 3 days at low levels of parasitosis

Rusa deer (Cervus timorensis) as a host for the cattle tick (Boophilus microplus) in Papua New Guinea.

Abstract: The rusa deer (Cervus timorensis) is more resistant to the cattle tick (Boophlilus microplus) than are Britsh breed cattle in Papua New Guinea. The average yield of replete female ticks from deer was 1.6% (0.3-3.2%) as compared to 11.2% (3.4-23.1%) from calves. Ticks from deer were more slender, lighter in weight and produced fewer eggs (mean 1,800) than did ticks from calves (mean 2,200) but the deer was shown to be an effective host. A cervid population can maintain a tick population in the absence of bovine hosts thus presenting an important factor in eradication programs. Nutritional stress appears to result in a higher seasonal prevalence of infestation amongst males and non-pregnant females.

Pig production in the Solomon Islands. II. Diseases and parasites.

Abstract: A study of diseases and parasites of pigs in the Solomon Islands during 1967 to 1969 indicated that infectious diseases were of little consequence. Four arthropod parrasite species were found: one tick, one louse and two tabanids. The tick (Amblyomma cyprium cyprium) was extremely rare. Fifteen species of helminth parasites were recorded and of these Stephanurus dentatus was the most prevalent. All species were identified except a filariid, of which only the microfilariae were seen.

Rickettsioses studies. 3. Natural foci of rickettsioses in south Bohemia.

Abstract: Antibodies against Coxiella burnetii and against rickettsiae of the spotted fever group were found in human sera and in sera from domestic and wild animals collected in south Bohemia. Spotted fever group rickettsiae were also discovered in the tick Ixodes ricinus. These results indicate the presence of both types of rickettsiae in this part of Czechoslovakia. As no epizootics or epidemics of Q fever have as yet been reported in the area, it can be assumed that C. burnetii occurs in the latent state. The occurrence of spotted fever group rickettsiae is probably endemic among I. ricinus ticks and among small and larger wild mammals.

Possibilities of persistence in new biotopes of ticks imported by birds.

Abstract: Survival and development of 6 tick species (Hyalomma anatolicum, Rhipicephalus sanguineus, Haemaphysalis punctata, Dermacentor marginatus, D. reticulatus and Ixodes ricinus) were studied in 3 groups differing in the range of distribution with respect to the place of importation, as a model for the knowledge of their possible inclusion in the new local biocenosis during transportation by natural hosts.

Feeding performance, survival and appearance of Dermacentor variabilis nymphs (Acari: Ixodidae), as influenced by host resistance.

Abstract: The research to date dealing with the phenomena of tick feeding and host resistance has been primarily concerned with the biochemical and physiological transformations which occur in the host (Allen, 1973, Int.J. Parasitol. 3 : 195–200; Boese, 1974, J. Med. Entomol. 11 : 503–12; Rick, 1962, Aust. J. Agric. Res. 13 : 532–50; Trager, 1939, J. Parasitol. 25 : 57–81). I know of no published studies on the various transformations (e.g., extended feeding time, decrease in the number of ticks successfully engorging and decrease in the engorgement size) manifested by the ticks during the development of host resistance. Such information is not only interesting but would be a great aid to those investigators who must project the yield of ticks, whether for control or rearing purposes, from a sensitized host. It was the object of this study, therefore, to report on these specific aspects as they occurred in the nymphs of Dermacentor variabilis .

Resistance to toxaphene by the Bont tick, Amblyomma hebraeum (Koch).

Abstract: A series of in vitro and in vivo trials confirmed resistance by the three-host Bont tick, Amblyomma hebraeum (Koch), to Toxaphene in the Cape, Natal and Transvaal Provinces of the Republic of South Africa, and in Swaziland and Transkei. Resistance was present in 80 of 97 field strains examined. Lindane and DDT resistance was present in the one field strain tested. The results of comparative in vivo hand spraying and plunge dipping trials confirmed those of the larval in vitro tests, thus validating the usefulness of this latter technique for identifying changes of susceptibility in field tick strains to ixodicides. Selection of Toxaphene resistance in A. hebraeum occurred within a period of four years when a 14-day interval of treatment was used continuously. The presence of all three tick instars in all stages of engorgement at the time of each treatment under this regimen is thought to have enhanced this selection.