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At least 19 recordsLinked to original sources
PubMed1979

Ticks and spirochetes.

The concept is expressed that Borrelia developed as symbionts of ticks (especially Argasidae) but act as parasites in mammals and birds ... borrelial reservoirs and amplifiers following bites by infected ticks. Certain tick borreliae may multiply in lice but one Borrelia has evolved into a n independent species (B. recurrentis) associated only with lice and humans. Seventeen argasid tick species are known as vectors of Borrelia species and 4 ixodid tick species are known as vectors of B. theileri.

Animals↗
PubMed1976

Human babesiosis on Nantucket Island: transmission by nymphal Ixodes ticks.

In order to identify potential vectors of human babesiosis (Babesia microli) in southern Massachusetts, I attempted to transmit the infection via nymphal ticks of that species found to be most abundant on reservoir hosts (Peromyscus leucopus) in nature. Mice were collected at frequent intervals throughout a year in a known enzootic focus on Nantucket Island, and ticks were removed by hand. Ticks of only two species were present; larvae and nymphs of Ixodes scapularis were about 10 times as numerous as were those of Dermacentor variabilis. Accordingly, I. scapularis were used in attempts to transmit a strain of Babesia derived from a human infection recently acquired near the study site. Larvae were permitted to feed on an infected hamster and nymphs derived from these larvae were placed on each of 11 non-infected hamsters. All but one hamster became infected. Nymphs reared from larvae that had attached to a non-infected hamster did not transmit babesiosis to other hamsters. These results suggest that I. scapularis serves as a vector of babesios-s on Nantucket hamsters. These results suggest that I. scapularis serves as a vector of babesiosis on Nantucket Island.

Animals↗
PubMed1978

[Light microscopic studies on the development of Theileria annulata (Dschunkowsky and Luhs, 1904) in Hyalomma anatolicum excavatum (Koch, 1844). II. The development in haemolymph and salivary glands (author's transl)].

Fully differentiated kinetes, average length 17.6 micrometer, appeared in the haemolymph of engorged nymphs usually 17 to 20 days after repletion. Kinetes were observed at first in the salivary glands on day 18 after repletion. The kinetes then transformed into fission bodies of about 10 micrometer in diameter, mainly in type III alveoli and less frequently in type II alveoli. The fission bodies grew up to a size of about 20 micrometer after several divisions of their nucleus. At this time the ticks moulted and no further development occurred until activation. Shortly before infestation the salivary glands began to proliferate, and rapid growth of the fission bodies was observed, especially in young ticks where development of 'infective particles' ('sporozoites') was concluded within two days. Development in feeding adult ticks apparently occurred in four major steps: (1) Division of primary fission bodies (sporonts) into numerous secondary fission bodies ('primary sporoblasts'), (2) division of secondary fission bodies into tertiary fission bodies ('secondary sporoblasts'), (3) production of particles ('sporozoites') by tertiary fission bodies and release of particles into the saliva, and (4) degeneration of fission bodies and their host cell but further release of particles. The host cell was stimulated to giant growth, thus its diameter increased, on average, from 15 to 110 micrometer. Heavy infections resulting from parasitaemias of greater than 40% caused disease and mortality in the tick population. Development was much retarded by aging. In ticks starved for six months 'sporozoites' did not develop before day five to seven of infestation. 'Sporozoites' did not develop before day five to seven of infestation. 'Sporozoites' may not develop at all in six to nine month old female ticks during the infestation period. The significance of the described developmental stages of T. annulata was discussed and a sexual generation postualted. The hypothetic development of T. annulata in its tick vector was illustrated.

Animals↗
PubMed1977

Chigger (Acarina:Trombiculidae) surveys of the west coast beaches of Sabah and Sarawak.

Leptotrombidium (Leptotrombidium) arenicola Traub, a vector of scrub typhus, had previously been found to occur in the coastal vegetation behind the edge of open sand along the beaches of Peninsular Malaysia. Surveys of the west coast beaches of Sabah and Sarawak were conducted to determine if this species occurs in similar habitat in East Malaysia on the island of Borneo. Leptotrombidium (L.) arenicola was not collected from the eighteen sites studied. Of the 11,982 mite larvae collected, 55 per cent were L.(L.) deliense (Walch), a well-known, widespread vector of scrub typhus.

Animals↗
PubMed1976

Distribution of suspected tick vectors and reported cases of Rocky Mountain spotted fever in California.

Evidence is presented for an area of human risk to Rocky Mountain spotted fever (RMSF) in California extending beyond the range of its classic tick vector, Dermacentor andersoni. Geographic, seasonal, and host distributions of Dermacentor variabilis and Dermacentor occidentalis suggest these species as potential vectors of RMSF in California outside the range of Dermacentor andersoni.

Animals↗
PubMedDate not supplied

[Basic trends in the research for the control of infected blood-sucking ticks and insects, the vectors of human diseases].

Attention was given to the necessity of control of the infected part of the population of vectors of transmissible infections. For this purpose it was suggested to investigate the nature of parasitism of the agent, to look for synergists of their pathogenic effect and to study the ecology of vectors in order to use control measures against the infected part of the population in the sites of aggregation.

Animals↗
PubMed1975

Plaque production by arboviruses in Singh's Aedes albopictus cells.

We report plaquing tests of 124 virus strains, mostly arboviruses of 21 serological groups, in Singh's line of Aedes albopictus cells. Thirty of these plaqued: all were arboviruses of six groups and were known or presumed to be mosquito borne. Failing to plaque were 86 strains of arboviruses, mostly tick borne, two strains of insect pathogens, and six animal viruses not classified as arboviruses. Among mosquito-borne agents, plaquing ability appeared related to serological classification. California group and most A-group viruses failed to plaque, but nearly all members of B and Bunyamwera groups readily plaqued. Within serological group B, 14 of 16 mosquito-borne agents plaqued, but none of 13 tick-borne or vector-unassociated viruses did so. Some implications of these results for recognition and classification of arboviruses are discussed.

Aedes↗
PubMed1979

Babesia infections in man.

Only recently has it been recognized that hemotropic animal parasites of the genus babesia are also human pathogens. Similar to malaria in both symptoms and laboratory findings, acute babesiosis generally results in self-limited illness, but it can be fatal in the asplenic patient. The widely disseminated vector tick, Ixodes dammini, can transmit infection at each stage of its development, larva and nymph as well as adult.

Adult↗