At

are likely to suffer. This might be a seasonal coincidence since it would appear that in European areas of Kenya the kennel tick is more common as an indoor pest than as an outdoor one. 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 1932. At the same time in coastal Mombasa, houses that were heavily infested by R. s. sanguineus yielded a number of cases of boutonneuse fever ("Tropical 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 (1953B) reported feeding by a kennel tick in the ear of a young girl. Specimens sent to Theiler (correspondence) from Beitbridge, Southern Rhode sia (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. sanguineus 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 Somaliland, 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 im pression has been gained that this tick attacks man more frequently 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 moderately large sized wild animals are not numerous.

Philip (1952) has remarked that during his fifteen months in West Africa he did not hear of a single dog owner being at tacked by this tick.

One of the most striking accounts of R. s. sanguineus attack ing persons comes from the Lake Region of Mexico. Elizondo Langagne (1947) wrote that this tick swarms in rural dwellings and indis 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 ticks 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, Tompkins (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 or refused to exhibit - tick bites on various parts of their body, 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 (1943A) 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 pain and distress as a result (Condorelli Francaviglia 1913). The Cameroons and Mexican 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 R. s. sanguineus on a patient and on his dogs. The patient showed no eschar but clinically resembled tick typhus; ticks from both kinds 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). Australia, this tick "seldom attacks man (Roberts 1939).

In

In Europe, Cox (1942) states, R. s. sanguineus commonly bites. man. From a review of the insignificant amount of supporting literature data, this would appear to be an overstatement. Through out the Mediterranean basin of Europe 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 role of the kennel tick as merely a reservoir of infection or as a vector from dog to dog. This concept may explain 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.

Cattle Hosts

Reports of the incidence of R. s. sanguineus on cattle show great disparity from locality to Iocality, as does the data in the present collection.

In the marshlands of Central Sudan cattle are frequently in fested by R. s. sanguineus, sometimes in large numbers, but in southern Sudan 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. s. sanguineus on cattle in tropical and southern Africa are decidedly rare, though 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. sanguineus "is not often found on cattle in Kenya; in fact, only 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. sanguineus Cattle in this colony are a privileged class with 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 R. sanguineus (are) encountered". [Unless shown otherwise, it might be assumed that, as a rule in Kenya, the presence of dogs influences the incidence of attacks on cattle, rather than vice versa (HH).7

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 account 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.

Canine Hosts

What may be a considerably varying incidence of R. s. sanguineus on dogs throughout tropical and south Africa is difficult to relate to any climatic or ecological factor in the absence of detailed surveys. Many published remarks on this subject appear to have been too hasty, since observations were not made over any extended period of time.

Lewis (1934) stated: "Although some Masai huts (in Kenya) sheltered many dogs, no R. sanguineus were found after diligent search"..... and (1939A) The tick has been observed to infest dogs heavily in townships and on farms; but the writer has never found (it) in native huts where dogs rest and sleep more or less with the family". This last statement is certainly contrary to our experience in Kenya and everywhere else.

On several recent trips to the southern Sudan we have checked native "pied dogs" and found them to be not only infested but frequently literally covered with R. s. sanguineus. Dogs kept by Europeans, when they were still in the Sudan, were usually so frequently deticked or doused with insecticide that a true picture of their infestation in relation to that of village dogs was im possible to obtain.

In the Kilimani area near Nairobi, dogs are infested with many specimens of H. leachii but few of R. s. sanguineus, while in lowland Mombasa R. s. sanguineus is by far the predominent species (Kauntze 1934). A number of generalized remarks con cerning the incidence of ticks on dogs are provided under R. simus (page 738).

S.

Feline Hosts

Domestic cats appear to be infrequent hosts of this tick. The large wild felines of Africa are sometimes attacked but then usually only by a few ticks.

Exceptional Hosts

Rare or unusual hosts that have been reported in Africa are: puff adder in Tanganyika (Loveridge 1928), bats (HH, collecting