Adult Ixodid Ticks Research Articles

The seasonal activity of adult ixodid ticks on Angora goats in the south western Orange Free State

Adult ixodid ticks were collected at 2-weekly intervals for a period of 23 consecutive months from 15 to 20 Angora goats on a farm in the south western Orange Free State. A total of 6 ixodid tick species were recovered. Rhipicephalus punctatus was the most abundant and prevalent tick. It was present from spring to late summer. Ixodes rubicundus was the next most abundant tick and was present mainly from March or April to July with peak numbers present in April or May. The onset of this tick's activity appeared to be stimulated by low atmospheric temperatures.

Exotic Ectoparasites of Ostriches Recently Imported into the United States

Eleven species of ectoparasitic arthropods were collected and identified from ostriches (Struthio camelus) recently imported into the United States from Africa and Europe. Four of these species are reported from ostriches for the first time. The parasites included adult hippoboscid flies (Struthiobosca struthionis) and 10 species of adult ixodid ticks (Amblyomma gemma, A. lepidum, A. variegatum, Haemaphysalis punctata, Hyalomma albiparmatum, H. luscitanicum, H. marginatum rufipes, H. truncatum, Hyalomma sp., and Rhipicephalus turanicus. As a result of these findings, the U.S. Department of Agriculture prohibited further importation into the United States of ostriches and other flightless birds on an interim basis.

Spotted fever group rickettsiae in immature and adult ticks (Acari: Ixodidae) from a focus of Rocky Mountain spotted fever in Connecticut.

Immature and adult ixodid ticks were collected during 1983 and 1984 in Newtown, Connecticut, an area endemic for Rocky Mountain spotted fever (RMSF), to determine prevalence of infection by spotted fever group (SFG) rickettsiae. Direct fluorescent-antibody (FA) staining revealed SFG organisms in 6 (1.8%) of 332 Dermacentor variabilis larvae, 5 (7.8%) of 64 D. variabilis nymphs, and in 2 (40%) of 5 Ixodes cookei nymphs removed from small- and medium-sized mammals. Hemolymph tests detected rickettsia-like organisms in 15 (8.8%) of 170 D. variabilis adults; 8 specimens retested by direct FA were negative. In contrast, hemocytes from 5 (8.6%) of 58 Ixodes texanus females contained organisms that stained positively in both hemolymph and direct FA tests. An indirect microimmunofluorescence test identified specific antibodies to Rickettsia rickettsii, the etiologic agent of RMSF, in serum samples from a chipmunk, raccoons, and white-footed mice. Results indicate that immature or adult ticks of at least three species may be involved in the maintenance and transmission of SFG rickettsiae at Newtown.

Identification ofTheileriainfections in living salivary glands of ticks

SUMMARYIt was found that interference contrast microscopy gave good morphological differentiation of the living and intact salivary glands from adult ixodid ticks,Rhipicephalus appendiculatusandAmblyomrna variegatum, removed by dissection. In many cases the individual cell types of the acini could be recognized. When the salivary glands of infected adult ticks were examinedTheileriaparasites were detected.Theileria parva, T. taurotragiandT. mutanscould be detected in the salivary glands after they reached the mature secondary sporoblast stage achieved even in unfed ticks. Parasites were detected only in type III acini. The morphology of tertiary sporoblasts and sporozoites of theseTheileriaspp. was clearly recognized in feeding ticks. Sporozoites ofT. parvaproved to be infective to cattle and to peripheral blood leucocytes of cattlein vitroafter interference contrast examination. Interference contrast examination of living salivary glands was used for selection of salivary glands with high infections ofT. parvasporozoites and the sporozoites could be separated in large numbers from these salivary glands. Using this technique it appeared possible to cloneTheileriaparasites from salivary glands with 1 infected acinus.

The structure of the Spiracles of the cattle tick, Boophilus microplus

The structures of the nymphal and adult spiracles of the tick, Boophilus microplus, have been examined by means of serial sections and a stereoscan electron microscope. Contrary to the views of recent writers, the functional openings of the spiracle have been found to be holes or aeropyles in the peripheral part of the spiracular plate of the adult tick. The ostium of previous writers is shown to be the ecdysial tube, which is present only in the spiracles of adult ixodid ticks. After the nymphal-adult ecdysis, the ecdysial tube is closed. There is thus no ostium in this stage, as has been claimed by previous writers who supposed that the chief or only route for gas exchanges between the atrium of the spiracle and the ambient air was through the so-called ostium. The ecdysial process of the spiracles of ticks is shown to be basically similar to the ecdysial process of the spiracles of certain insects such as scarabaeid larvae and the larvae of some Diptera-Cyclorrhapha.