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Dissimilarity of frequent hosts from area to area is apparent. Obviously, the numbers and kinds of available animals vary over the great area infested by this tick and different climatic and ecolog. ical conditions affect the parasite's life cycle and its relation to different hosts. In certain areas, physiological races special. ly adapted to feeding on certain hosts may exist.
It appears well established (1) that domestic dogs are most frequently parasitized by R. s. san 'neus (though in tropical and southern Africa, Haema-h.§alis I. Ieachii is often more common on dogs), (2) that parasitIsm of Iarge groundfeeding birds, hares, hedgehogs, and domestic sheep and goats is common, (3) that all wild carnivores within the tick's range are frequently though seldom heaviky parasitized, and (A) that wild ruminants and man are only erratically chosen as hosts. Wild animals in zoological gardens and others living under domestic conditions, especially when in manmade buildings or enclosures, are particularly sus. ceptible to attack by this parasite.
Available information on human parasitism by the kennel tick is difficult to evaluate. From accounts of this species in rela. tion to boutonneuse fever in northwestern kfrica and in southern Europe, it would appear that human beings are more frequently bitten in these areas than elsewhere in Africa. There is, however, no conclusive evidence, as et, that this is true. The-Eonsiderable 'k§nneI tick popuIat1ons I5 Nbrth Ifrica and-the density and intimacy of human beings and their domestic animals may be responsible for the greater incidence of human infestation in this area, as sug_ gested by Philip (1952). At the same time consideration should be given to the possible existence of a biological race with a greater predilection for feeding from man.
In tropical and southern Africa, though isolated reports of parasitism of man exist, only Roberts (1933) and workers of his period in Kenya have published accounts of serious infestation.
On one occasion boutonneuse fever, attributed to R. san 'neus but without biting specimens, was so prevalent that it caused disorganization of staffing arrangements of the Kenya and Uganda Railways. Roberts stated that when the land is covered by stand. ing water these ticks seek shelter in houses and human inhabitants
are likely to suffer. This might be a seasonal coincidence since it would appear t at in European areas of Kenya the kennel tick is more common as an indoor pest than as an outdoor one. At least, an interesting research problem on the overall subject is suggested£7
Only a single report of the kennel tick attacking people in the upland Kilimani area near Nairobi reached the Kenya Medical Research Laboratory during 1992. At the same time in coastal Mombasa, houses that were heavily infested by R. s. s 'neus yielded a number of cases of boutonneuse fever-(“tropic§I typhus“) following bites on the patients‘ body and legs, some resulting in primary lesions, and all definitely associated with this tick species (Kauntze 1934). In Cameroons, Rageau (l953B) reported feeding by a kennel tick in the ear of a young girl. Specimens sent to Theiler (correspondence) from Beitbridge, Southern Rhodesia (on the Limpopo River just beyond Messina) were said to have been biting people and causing great discomfort.
The few present records for parasitism of man by this tick in the Sudan are noted in the Equatoria and Upper Nile Province records above. Further, my associates and I have been bitten by R. s. san ‘neus at Njoro, Kenya; several times in the wilds of southeastern Egypt, on the Mediterranean littoral, and in the oasis of Sinai; not infrequently in the mountains and lowlands of the Yemen; and once each in Aden Protectorate, French Somali. land, Eritrea, and Turkey. These incidents, while not common during many months in the field, bear consideration. we have never known of an Egyptian being bitten in Cairo or in the Nile Valley. After several years of canvassing the American community in Cairo, many of whose members have this tick in their home, only three children have been reported to be infested.
From field experience in Africa and the Near East, the in» pression has been gained that this tick attacks man more fre_ quently in hot, dry areas than elsewhere, and especially that it does so in those situations where it is a common pest of
cattle, sheep, and goats, but where domestic dogs and moderate. ly large sized wild animals are not nuerous.
Philip (1952) has remarked that during his fifteen months in West Africa he did not hear of a single dog owner being attacked by this tick.
One of the most striking accounts of R. s. s neus attack. ing persons comes from the Lake Region of Hefico. fizondo Langagne (191.7) wrote that this tick swarms in rural dwellings and indie. criminately attacks persons or dogs. In this area more than five hundred peasants, mostly young children, presented themselves at clinic for removal of adult ticks feeding in the canal of the external ear. These t'iaZs_were considered responsible for the cases of Rocky Mountain spotted fever that were especially fre
quent among children.
Much further north, in the State of New York, Tomplcins (1953) found a specimen of this tick, that "had almost certainly left a rabid fox" embedded in his own left axilla. Other laboratory technicians exhibited .. or refused to exhibit - tick bites on various parts of their bow, but the attacker species was not identified. The human victims did not become rabid.
Previously, Philip (1952) had noted the few instances in which the kennel tick is known to have fed on people in the United States and he summarized the small amount of available data. A single case of a female tick biting a person, near the ankle, in Nebraska has been presented (Helm 1952). Fiasson (l943A) indicates that this tick does not bite man in Venezuela.
A notable Italian incident involved a female kennel tick lodged in the ear of a person who suffered severe ‘n and distress as a result (Condorelli Francaviglia 1913 . The Cameroons a.nd Meacican cases noted above were also reported from human ears.
In his study of Indian tick typhus, Philip (1952) indicated his belief that persons acquire this disease through bites of kennel ticks that have previously fed on infected dogs. There are, however, very few records of this tick attacking man in India. One such noted E. 3. sanguineus on a patient and on his dogs. The patient showed no esc ar but clinically resembled tick typhus; ticks from both lcinds of hosts were infected but the dogs were not (Rao 1951). Four records of kennel ticks from man in India were presented by Strickland and Roy (1939). In Australia, this tick "seldom attacks man‘ (Roberts 1939).
In Europe, Cox (1942) states, R. 3. san eus commonly bites man. From a review of the insignificant amouné of supporting
literature data, this would appear to be an overstatement. Through. out the Mediterranean basin of Euope to as far east as the Crimea and Kashmir, and in Northwest.Africa, various forms of the fre_ quently common disease, boutonneuse fever, are considered to be transmitted only by the bite of this tick. However, the wide. spread presence of the disease in these areas coupled with the
few definite reports of the actual arthropod biting man, suggests that our present concepts of the epidemiology of this disease may eventually have to be revised.
Interestingly enough, since the above was written, French workers have theorized that transmission of boutonneuse fever from dogs to man is actually usually accomplished by rubbing one's eyes after deticking dogs or by some insect, especially a reduviid or some other Heteroptera (Sigalas and Lamontellerie 1954). A similar theory had already been advanced by Berri (1953) in Italy. While this novel approach remains to be demonstrated, it suggests the r6le of the kennel tick as erely a reservoir of infection or as a vector from dog to dog. This concept may eplain the few definite records of this species as a parasite of man, even where the Mediterranean type of boutonneuse fever is common.
Lamontellerie (1954) presents some evidence to support his view that in southwestern France the kennel tick displays little if any aggresiveness in attacking man, even though boutonneuse fever is common. He cites some published references to indicate that the tick sometimes does attack man, but most of these refer to generalized or vague statements or to obvious repetitions of previously published reports.
In Manila, since it was claimed that larval kennel ticks at_ tacked children, de Jesus (1939) attempted without success to induce larvae to feed on two men and on two children.
Reports of the incidence of R. s. san 'neus on cattle show great disparity from locality to Ioéali y, as oes the data in the present collection.
In the marshlands of Central Sudan cattle are frequently in. fasted by R. s. s "uineus, sometimes in large numbers, but in southern Sfidafi cattle are only exceptionally and never severely infested. This fact may corroborate Roberts‘ suggestion (above) that at flood periods this parasite seeks exceptional shelter and hosts.
Reports of R. 3. san"uineus on cattle in tropical and southern Africa are decidedly rare, .ough a few exceptions have been noted. The incidence of cattle infestation greatly increases as one travels through northern Sudan to the Mediterranean, but it is by no means constant. In certain localities of Yemen and Eritrea the incidence on cattle is fairly high (HH observation).
Fotheringham and Lewis (1937) state that R. s. san 'neus "is not often found on cattle in Kenya; in fact, Bnly on a few occasions have very small numbers been collected from this host". Out of 200 nymphs placed on cattle by these investigators, only five fed. On the other hand, according to Roberts (1935), "it is of some importance to note that cattle in certain areas (of Kenya) carry quite a large population of R. sanégineus ...... Cattle in this colony are a privileged class wi unrestricted license to wander over township areas and even in gardens if herbage is available. (These animals) thus become a very potent factor in the distribution of ticks in residential areas. House dogs wandering in grass along roadsides and gardens gather up these ticks and carry them eventually into houses (where) enormous numbers of E. san 'neus (are) encountered". Z-Unless shown other. wise, it might e assumed that, as a rule in Kenya, the presence of dogs influences the incidence of attacks on cattle, rather than vice versa (H)i7
Cultural patterns of pastoral peoples probably influence the presence of kennel ticks on cattle, especially in those tribes where families and animals sleep in the same hut or corral, a not uncommon practice in Africa. This feature may also largely ac. count for the occasional finding of another dog tick, H. leachii, on cattle. A survey of the present Africa, Arabian, and Near East collections indicates the considerable importance of this relation. In Bechuanaland, Theiler believes (correspondence), the kennel tick survives only where such conditions prevail, especially where cattle, goats, sheep, dogs, and people congre. gate around wells and pans.