Page images

density of this tick is around haystacks and in fallow fields where their immature stage host, the European hare, hides and feeds. Engorged nymphs drop from hares in autumn and overwinter in that stage. They molt in the spring, and adults attack cattle, sheep, horses, and man. The devastation of the Crimea during the war, followed by a great increase in hares and their ticks, was significant epidemiologically in the outbreak of highly virulent, often fatal hemorrhagic fever at that time.


Gynandromorphs of H. marginatum have been described and il lustrated by Pervomaisky (1950). The same author (1949) was un able to secure a complete Fı generation from parthenogenetic females of this species.

Schulze (19320) illustrated certain of the cuticular sense organs of two of his "subspecies of this species, also "gyno tropes", males with more dense punctations on the scutum con forming to those of the female scutum in location and distribu tion. This species has been utilized in a study of sensory physiology (Totze 1933).

When large numbers of ticks (as H. plumbeum) feed on a restricted area of the host, the females and sometimes also males fail to engorge completely and may die; their development is far from normal. When different species are competing for the same feeding area, this additional competitive factor often hinders their normal development (Pavlovsky, Pervomaisky, and Chagin 1954).


MAN: H. marginatum is considered to be the chief vector of the virus of Crimean hemorrhagic fever. The extensive geographic range of this tick and its large population in many areas where it occurs - factors that suggest a high potential as a medically important species - appear to be generally unappreciated outside of Crimea. This species is not involved in the transmission of Omsk hemorrhagic fever, since it does not occur in that area, so far as is presently known.

Specimens naturally infected with fever (Coxiella burnetii) have been found; this species is a vector of the organism and transmits it through all stages including the egg.

Brucellosis or undulent fever organisms, Brucella melitensis, survive some time in this tick, which is said by some Soviet workers to be a carrier and transmitter of this pathogen. Some Russian studies of ticks as animals sustaining natural foci of tularemia have negated the importance of H. marginatum (as H. plumbeum) in this regard, although other workers have reported The finding of naturally infected specimens.

CATTLE: Theileriasis (Theileria spp.).

HORSES: Theileriasis (Theileria equi) and piroplasmosis (Piroplasma caballi). Transovarial transmission of the latter organism to the seventh generation has been demonstrated.

GUINEAPIGS: Rickettsiae pathogenic to these animals and transovarially transmitted to the F3 generation of H. marginatum have been reported.


Males: The combination of characters for recognizing typical males is: (1) the center of the subanal shields is directly pos. terior of the central axis of the adanal shields (which are large and broad); (2) the lateral grooves are long, reaching approximately to the eyes, but they are frequently somewhat obscured by dense punctations or by lack of discreteness, especially anteriorly; (3) the scutal punctations are dense and large in the distal and scapular fields, but variable elsewhere, being usually smaller and more shallow and less dense centrally; (4) the posteromedian groove reaches the scutal midlength, it is narrow anteriorly and wider posteriorly; the paramedian grooves are about half as long as the posteromedian groove and taper from a pointed apex to wide in the festoon area; a narrow heavily punctate ridge lies between the paramedian grooves and the lateral grooves.

The scutum is usually comparatively narrowly elongate, meas uring approximately 4.0 mm. long and 2.5 mm. wide. Its color is typically dark brown to black, but reddish specimens also occur; the legs may be entirely reddish or reddish centrally on each segment with paler anterior and posterior bands (see next para graph). The scutal punctations may be dense enough to suggest H. rufipes, but those in the center are shallower and smaller Than elsewhere, while in H. rufipes they are deep and quite uniform in size and depth. The parma may appear to be merely a median festoon and is the same color as the rest of the scutum. The subanal and ad anal shields have rounded contours; the adanal shields are quite large.

Heavily punctate males, as seen among series from Libya, Algeria, Egypt, Romania, and elsewhere may suggest H. turanicum (page 531). The legs of H. marginatum, however, lack the con spicuous enamelling characteristic of those of H. turanicum.

Females: The genital apron is a large, robust widely trans. verse oval or triangle with a strongly bulging profile; it is most characteristic. The scutal punctation consists of numerous small, shallow, distant punctations over the entire surface (they may be almost medium size and slightly deeper and closer), and a few larger and deeper punctations scattered among them chiefly on the anterior half of the scutum. The basic punctation in some specimens is so shallow as to give scutum a rather smooth appear. ance, especially posteriorly. The central field between the cer. vical grooves is usually lighter (more reddish) than the dark lateral fields. The scutum appears to be exceptionally wide, its length_width ratio being about equal or shorter than wide.

Females of H. marginatum and H. turanicum are quite similar but the bright enamelling of the leg segments of H. turanicum distinguishes them. In most specimens of H. turanicum the genital apron is not so widely triangular and the scut al punctations are more numerous and discrete than in H. turanicum.

The larva and nymph of H. marginatum have been described and illustrated by Bernad skaia (19390) and Feldman_Muhsam (1948).

[ocr errors][graphic][subsumed][subsumed][ocr errors][subsumed][subsumed][subsumed]

Figures 182 and 183, 0, dorsal and ventral views
Figures 184 and 185, 2, dorsal and ventral views

A, & genital area, B to D, genital area outline and profile.

B, unengorged. C, partly engorged. D, fully engorged.





(Figures 182 to 185)


NOTE: H. rufipes is a most distinctive tick although Schulze, Delpy, and Feldman_Muhsam in their earlier reports confused H. rufipes under the name H. impressum. Nuttall during the first quarter of the 1900s identified African specimens as H. aegyptium impressum and many British and some Italian workers of this period followed this precedent. The only other African species of wide range, H. truncatum, was referred to by this school as H. aegyptium. A few Russian synonyms are listed in the distribution section below, but contemporary Soviet usage concerning the nomenclature of this tick appears to be incorrect.

[merged small][merged small][ocr errors][merged small]
[ocr errors][merged small]

Torit Syncerus caffer aequinoctialis Dec
Khor Waat Syncerus caifer aequinoctialis (MCZ)
Torit domestic cattle

Jan (2)
Torit domestic cattle

Torit domestic cattle

Torit domestic cattle

domestic cattle

Terakeka domestic cattle

Mar (sv)
Tali Post domestic cattle

Mar (SVS Meridi domestic cattle

Jan (SVS) Y ambio domestic cattle



H. rufipes is widely spread in the Sudan but is numerous only in the semiarid central area. The following are localities from which specimens (all from cattle unless otherwise noted) have been seen:

« PreviousContinue »