Showing papers on "Tick published in 1975"

A review of Rocky Mountain spotted fever (tick-borne typhus), its agent, and its tick vectors in the United States.

Abstract: Rocky Mountain spotted fever (tick-borne typhus) is the most important rickettsial disease in the United States. Its changing status since the beginning of this century is reviewed, and the various factors responsible for the recent increase in disease incidence, which in 1974 reached record proportions, are discussed. Reference is made to the large variety of ixodid ticks which has been found naturally infected with Rickettsia rickettsii or with related but distinct rickettsial agents, and the findings of recent studies pertaining to population dynamics and host relationships of various tick vectors are presented. Also reviewed are technical advances in methodology applicable to rickettsial research, particularly those procedures which may lead to a more efficient diagnosis or prevention of spotted fever. Finally, those steps are outlined which would bring about a decrease in the morbidity and mortality of this disease.

Patterns of distribution of the tick Ixodes trianguliceps Birula on its hosts

Abstract: The survival of a single parasite is dependent on individual adaptations in relation to its specialized situation, while the evolution and survival of the parasite species is the product of an ecological relationship with its hosts at the population level. The patterns of distribution of the parasite on its hosts reflect the biological factors working within the host-parasite interaction (Crofton 1971a, b; Schmid & Robinson 1972), thus providing insight into the nature of the adaptive mechanisms permitting the survival of the parasite species. During a three-year study of the ecological relationship between the tick, Ixodes trianguliceps Birula 1895, and its small mammal hosts (Randolph 1973b) the tick infestation patterns were analysed with respect to the distribution of the ticks on the host population as a whole, and with respect to the variation in tick infestation levels on the different species of hosts and the intraspecific groups of hosts. This latter factor is very important to the understanding of the tick-host relationship, not only because the disparity reflects the importance of each small mammal species as hosts to this parasite, but also because the basis of its cause must lie in the mechanics of how the ticks are picked up and allowed to attach successfully.

Cattle and the paralysis tick Ixodes holocyclus.

Abstract: Paralysis of domestic stock by the paralysis tick Ixodes holocyclus is chiefly a disease of young animals (especially calves) and of non-habituated stock introduced into tick-infested country in spring. The tick has a wide host range, but its principal hosts are bandicoots. The tick has one generation per year and the adult female, which causes almost all paralysis, is abundant in spring and early summer and occurs most commonly in overgrown or regrowth country where bandicoots are abundant. The distribution and behavior of the long and the short-nosed bandicoots are reviewed. The number of ticks required to induce paralysis in cattle and the protection from paralysis afforded by prior experience of the tick are discussed.

Rocky Mountain spotted fever (tick-borne typhus) in South Carolina: an educational program and tick/rickettsial survey in 1973 and 1974.

Abstract: Because the incidence of spotted fever is increasing in South Carolina, campaigns were carried out in 1973 and 1974 to provide the public and medical practitioners, through pamphlets and news media, with information about spotted fever and the ticks which transmit the causative agent, Rickettsia rickettsii. People were also invited to save and submit live ticks removed from vegetation, animals and humans, for examination by the hemolymph test. A total of 1,186 ticks consisting of 987 Dermacentor variabilis, 103 Rhipicephalus sanguineus, and 96 Amblyomma americanum were examined. Rickettsiae identified by direct immunofluorescence as members of the spotted fever group were detected in 49 (4.9%) of the D. variabilis, and 16 (16.6%) of the A. americanum ticks. Two hundred and twenty (199 D. variabilis, 17 A. americanum, and 4 R. sanguineus) were recorded as having been attached to 199 persons. Nine of these ticks (8 D. variabilis, and 1 A. americanum) were hemolymph test-positive for spotted fever-group rickettsiae. Infected ticks originated from each of the three major South Carolina biogeographic regions, namely Piedmont, Sandhill, and Coastal Plain. Since education is the first and most important step in preventing spotted fever, educational programs and tick examination services similar to those described, are suggested for other states with high spotted fever incidence.

A review of the evidence in retrospect for a rickettsial etiology in Bullis fever.

Abstract: The authors have presented evidence through work done 25-30 years ago for the rickettsial etiology of Bullis fever, a forgotten epidemic which occurred with over a 1,000 cases among World War II troops in training at Camp Bullis, Texas. Rickettsiae were recovered from blood and lymph nodes of patients and from ticks, Amblyomma americanum, collected in the area. All patients gave a history of tick-bites. The human and tick strains of rickettsiae, carried in chick embryo culture and in animal passage, were found to produce the characteristic syndrome of Bullis fever in human volunteers inoculated with either strain, indicating identity and specificity of infection. Wildlife in the area was found to support the stages in the life cycle of A. americanum. Deer were implicated as supporting the most abundant adult tick population, the stage which attacks man. Serologic studies eliminated othe rickettsial diseases, Colorado tick fever, dengue and many other diseases. The name Rickettsia texiana is suggested for the hitherto un-named member of the rickettsia group of organisms.

African swine fever: an epizootiological review with special reference to the South African situation.

Abstract: The most important characteristics and the distribution of the viruses of African swine fever and hog cholera are reviewed. Both viruses were probably present simultaneously in South Africa in the first two decades of the century. While hog cholera was eradicated by 1918, African swine fever persists to the present day because it has a different epizootiology. The role played by wild pigs and the argasid tick (Ornithodoros moubata porcinus) in the epizootiology of African swine fever is discussed and an account of the outbreaks of the disease in South Africa from 1926 to 1974 is given. It appears that the disease in the Transvaal has had a cyclic occurrence.

Apparent host selection by some african tick species

Abstract: 1. Four cattle were exposed to tick infestation in a game-dominated territory for 21 months. All ticks seen crawling on two of the cattle were collected; the other two were thoroughly deticked once daily. The results estimate the gross daily pick-up and the nett daily infestation. 2. The overall gross/nett ratio, the loss-rate, of ticks picked up was 1.76:1. 3. The four main species present separate into two categories, A (R. evertsi and R. appendiculatus) with loss rates of 1.48:1 and 1.53:1, and B (A. hebraeum and H. truncatum), rates 2.25:1 and 2.29:1. Less extensive data for H. rufipes and R. simus put them in categories A and B, respectively. 4. The degree of specialization to predilection sites for attachment is measured, and corresponds to the observed adaptation of the species to domestic cattle. 5. It is suggested that the greater proportion of successes in infestation by category A species results from a higher receptivity to specific bovine stimuli for attachment; about 30% of category B ticks on the other hand reject cattle.

Evaluation of CO2-baited traps for survey of Amblyomma maculatum Koch and Dermacentor variabilis Say (Acarina: Ixodidae).

Abstract: The use of CO2-baited traps for surveying lone star ticks has been described by Wilson et al. (1972, J. Med. Ent. 9 : 245–52) and Semtner & Hair (1973, J. Med. Ent. 10 : 618–28). These papers also review the use of CO2 for the collection of other tick species.

The effect of host species on the engorgement, molting success, and molted weight of the Gulf Coast tick, Amblyomma maculatum Koch (Acarina: Ixodidae).

Abstract: Feeding studies were done with the larvae and nymphs of the Gulf Coast tick, Amblyomma maculatum Koch, using the Deer Mouse, Hispid Cotton Rat, Eastern Woodrat, Bobwhite Quail, Black-tailed Jack Rabbit, the Raccoon, and the Opossum as experimental hosts. Engorgement weight, engorgement time, engorgement success, molted weight, molted adult dimensions, and percentage of molting success were determined for similarly aged and treated ticks reared on artificially infested caged hosts. Data were averaged for several hosts of the same species and mean comparisons were made to determine if host species had any effect on parameters measured. Differences associated with quantity and possibly quality of the ingested meal from different host species caused differences in the molted tick weights. The engorgement time and success were host-species dependent, but the percentage of molt was greater than 85% within all host species groups. No difference in the measured dimensions of the adult ticks of similar weight could be attributed to host species.

Isolation of Nyamanini and Quaranfil viruses from Argas (Persicargas) arboreus ticks in Nigeria.

Abstract: During October 1970, 2324 ticks of the species Argas (Persicargas) arboreus were collected from under the bark and in crevices of trees frequented by Cattle Egrets ( Bubuleus ibis ibis ) at 2 sites in North Eastern State, Nigeria. These specimens, when processed as 119 pools and inoculated intracerebrally into infant mice, yielded multiple strains of 2 viruses previously unreported from Nigeria: Nyamanini (15 strains) and Quaranfil (16 strains). A single tick of the genus Ambryomma , collected at the samme time, did not yield virus.

Development of Theileria mutants (Aitong) in the tick Amblyomma variegatum compared to that of T. parva (Muguga) in Rhipicephalus appendiculatus.

Abstract: A comparison was made between the development of Theileria mutans (Aitong) in adult Amblyomma variegatum ticks and the development of T. parva (Muguga) in adult Rhipicephalus appendiculatus ticks. Both batches of ticks dropped as engorged nymphs from cattle whose intraerythrocytic parasitemias were approximately 40%, and it was thus possible to make a direct comparison of the infection rates produced in their tick hosts in this experiment by the 2 species of Theileria. Ticks of the 2 batches were fed in ear bags on rabbits, and equal numbers of male and female ticks were removed daily for 5 days. The salivary glands were dissected out from these ticks, and from unfed ones in each batch, processed, and examined for Theileria parasites, which were categorized according to their morphological maturity. The A. variegatum ticks had a lower rate of infection with Theileria. Fewer parasites were observed in the ticks, and they took longer to mature. When the development of the 2 species of Theileria was compared, the major difference appeared to be that T. mutans had large Babesia-like infective particles.

Correlation between the morphology and infectivity of Theileria lawrencei developing in the tick Rhipicephalus appendiculatus.

Abstract: Adult Rhipicephalus appendiculatus ticks, infected as nymphs by feeding them on an African buffalo harbouring Theileria lawrencei, were applied to the ears of rabbits. Equal numbers of the feeding ticks were removed daily from rabbits and either dissected and processed so that parasites in their salivary glands could be examined morphologically and classified, or ground in Eagle's Minimal Essential Medium, to harvest parasites from the ticks in the resultant supernatant fluid. The infectivity of the supernatant fluid was tested by inoculation of aliquots into groups of susceptible cattle. It was found that supernatant fluids produced from day 0 to day 2 fed ticks were uninfective to cattle but those produced from 3 to 9 days were infective. The most infective supernatant fluid was produced from 6 day fed ticks. The reactions resulting in cattle were correlated with the number and morphology of parasites in sections of salivary glands and it was found that mature parasites coincided with infectivity of the supernatant fluid to cattle. From the reactions in cattle inoculated with supernatant fluids from 5 and 6 day fed ticks it was concluded that this method of harvesting parasites was efficient. Examination of the salivary glands of a representative sample of a T. lawrencei infected tick batch is a potential means of screening material for T. lawrencei stabilates.

The biology of the kangaroo tick, Ornithodoros (Pavlovskyella) gurneyi Warburton (Acarina: Argasidae), in the laboratory.

Abstract: A method for culturing the kangaroo tick Ornithodoros gurneyi is described. Data are presented on hardening of newly molted ticks, on the feeding and detaching of all stages, on the molting and development of engorged larvae and nymphs, and the regulation of a reproductive diapause.

Isolation of viral and rickettsial agents from Panamanian Acarina.

Abstract: Over a 21-month period, large and diverse collections of Acarina parasitic on Panamanian vertebrates were tested for infection with arboviruses and rickettsiae by inoculating suckling mice or guinea pigs with pooled specimens. Most specimens tested were rodent parasites of the families Trombiculidae, Laelapidae, Ixodidae, and Macronyssidae. No viruses were recovered from 468 pools of mites, but 2 strains of unidentified, filterable agents were isolated in mice from 2 of 173 tick pools. One isolate was from a pool of 75 immature Amblyomma sp. and 9 larval Haemaphysalis juxtakochi taken off the Coati Coatimundi), Nasua nasua narica , in Gamboa, Canal Zone C.Z.). The other was from 1 male Amblyomma parvum and immature Amblyomma sp. pooled from mixed hosts and localities of C.Z. Both strains were of low and variable pathogenicity for mice and failed to survive frozen storage. Evidence of rickettsial infections of mites was seen in 3 instances: Coxiella burneti was recovered in a guinea pig from a pool of 13 chiggers, Intercutestrix mondolfii , taken off the Spiny Rat, Proechimys semispinosus , in Pina, C.Z. Two additional pools of mites were infected with C. burneti as shown by serological conversion of inoculated guinea pigs. One of these pools consisted of 27 chiggers ( Tecomatlana sandovali ) off bats ( Saccopteryx bilineata ) in Panama Province. The other contained 226 mixed Laelapidae off C.Z. rodents. Rickettsia rickettsi was isolated in a guinea pig from 20 immature Amblyomma sp. pooled from mixed hosts in the C.Z. These results indicate that parasitic mites play a minimal role, if any, in circulating arboviruses in this area of the Neotropical Region. In addition, further evidence is provided for the possible participation of mites, including chiggers, in the natural cycle of Coxiella burneti .

Tick-borne viruses in Finland.

Abstract: Ixodes ricinus is the only one of six tick species reported from Finland found to carry viruses. It transmits tick-borne encephalitis and Uukuniemi viruses, and transmission of a Kemerovo group virus is suggested by antibody findings. Tick-borne encephalitis is common only in the SW-archipelago; it is also found near the SE-boarder but is very rare elsewhere. In contrast, Uukuniemi virus is common throughout the distribution area of I. ricinus, being commoner on the mainland than in the archipelago. Medium, large and small mammals participate in the cycle of tick-borne encephalitis virus, though birds are not excluded and apparently they act as host to the Uukuniemi virus. The encephalitis virus causes clinical illness in man, with cases limited mostly to the SW-archipelago; the disease is a relatively mild form of tick-borne encephalitis, with biphasic and meningeal symptoms dominating.

[Observations on the behaviour of coxiella burneti in the argasid tick ornithodoros moubata (author's transl)].

Abstract: Based on a long-term study of many years, a report is given on the behaviour of Coxiella burneti in the argasid tick, Ornithodoros moubata. Recent observations were made on ticks infected on mice and subsequently maintained separately. Particular emphasis was placed upon the localization of the ricksettsiae in certain organs of the ticks, its excretion -also with regard to routes of transmission - and transovarial passage. C. burneti invade primarily the gut epithelial cells of the tick and these cells remain infested with the causative agent throughout the entire life of the vector. After a certain infection period, other organs of the tick may become also infected. Thus, infection of the coxal organ, of salivary glands, rectal ampullae and ovaries has been confirmed through the presence of the rickettsiae in the coxal fluid, saliva and excreta or through transovarial passage of the agent with the saliva during feeding transmission to a new host takes place. Infection of the various organs of the tick and excretion or passage of the agent is not necessarily the rule, but may be even considered as an exception. This is especially the case for transovarial passage. On the other side, the multiplication of rickettsiae in the tick can be so intensive that the haemolymph and all internal organs become flooded with the organisms. These observations have been made in moribund and dead ticks. One of the most remarkable results was that the behaviour of C. burneti in its tick host varied considerably not only within the same series of experiments but more frequently in one and the same individual tick as well. Thus, e.g. excretion of the agent - with the saliva or coxal fluid - could be interrupted and resumed again later on. Evidently, these variations indicate a shift in the host-parasite interrelationship in which the multiplication of the rickettsiae is greatly enhanced by a decrease in the host's immune response, whereas an increase in its defence reaction will cause suppression of multiplication. It is not known, however, if the relevant impulse is primarily given by the tick or the rickettsial organism. The behaviour of C. burneti in O. moubata which does not follow a definite pattern coincides well with the high adaptability and variability characterizing this microorganism in other aspects as well.

Mechanism of action of clenpyrin on the cattle tick Boophilus microplus

Abstract: Clenpyrin is effective against all stages of development of one-host cattle ticks (Boophilus spp.) including strains resistant to organophosphorus compounds and carbamates. Ticks treated with clenpyrin are quickly immobilised due to a slackening of the muscles. Manometric measurements revealed a marked depression in respiratory gas exchange and a rise in the R Q within 24 h after treatment. Clenpyrin inhibits NADH oxidation and, as a result, all synthesising processes in the tick. The breakdown of proteins taken up with the blood meal is also inhibited. Clenpyrin, however, does not interfere with carbohydrate degradation. These results have been corroborated in detail by determining various substances in treated and untreated ticks: proteins, haematin, guanine, glycogen, glucose, lactate, ATP, lipoids and cuticular wax. Clenpyrin does not inhibit tick proteinase, tick and other acetylcholinesterase, or rat monoamine oxidase; therefore, the mode of action of clenpyrin differs from that of other known tickicides, especially those involving the acetylcholinesterase system.

Letter: The brown dog tick (Rhipicephalus sanguineus) on an imported dog.

Abstract: Extract Sir, — We wish to record the presence of the tick Rhipicephalus sanguineus on a dog imported from Australia. This tick is mainly parasitic on dogs although on rare occasions it has been collected from non-canine hosts (Roberts, 1965). Experimentally it has been shown capable of transmitting a wide variety of serious diseases but its role as a natural vector of many of them is unknown. In Australia it has been demostrated as being naturally infected with Coxiella burnetii (Smith, 1942) and is recorded from all continents and some oceanic islands lying between latitudes 50°N and 36°S (Roberts, 1970). Auckland falls within this boundaries and therefore it is not unreasonable to suggest that R. sanguineus could become established in New Zealand.

Boophilus microplus (Canestrini) (Acarida: Ixodidae) on the bovine host. II. Distribution of stages during development.

Abstract: Distribution of the larvae, nymphs and adults of a population of Boophilus microplus was determined over 21 body areas of the host. The data indicated that certain areas were more favoured (or tick survival in these areas was better) by the ticks than others, each stage having preferred zones, the older ticks proportionally more numerous on the posterior portions of the host. The pattern of distribution of the tick populations on susceptible, resistant, and resistant calves restrained from self-grooming, were similar.