Clinical and pathological investigations on camel skin diseases in some camel rich districts of Northern Kenya
Clinical and pathological investigations on camel skin diseases were undertaken in Turkana, Samburu, Isiolo and Marsabit districts in northern Kenya between October 1990 and November 1991. Nomadic camel herds were selected based on accessibility. The origin, domestication, population, distribution, socio-economic importance, constraints to development of camel husbandry in Kenya, and diseases of the camel (emphasizing on the skin diseases) are reviewed. Out of 11,196 camels examined, 53.2 per cent had skin diseases/lesions. All camel herds were found to be infested by ticks and camel flies at varying levels of infestation. The commonest and most widespread diseases were Mange (45.7 per cent), camelpox and skin abscesses (20.1 and 17.4 per cent respectively). In addition to the previously known Sarcoptes scabiei var cameli ,four other new mite species were found. The first of these was a minute 'beetle-like' mite christened Cardiocephaloptes marti, new genus and species (new sub-order and new family). This is a tiny lymph sucking mite, about half the size of S. scabiei. The body is shaped like that of a beetle. It has a large falsehead which is shaped like the sign of a heart on a playing card with the pointed end facing anteriorly. The male is only three quarters the size of the female. The first and third pairs of legs are similar in both sexes, but there is a marked difference in the other two pairs. Leg two in the male has a characteristic lanceolate appendage sticking out laterally between the femur and the genu, w• hereas in the female it is somewhat shrivelled. Leg four in the male is short, large and bears a powerful claw, shaped likethe dewclaws of a lion, and long straight setae whereas in the female it has only three segments, at the end of which there is a pair of long whiplike setae which are equal in length. The second and third were large-sized mites belonging to the family dermanyssidae. Camelonyssus golfer, (new genus and species) is a blood sucking mite which bears strong resemblance to members of the genus Dermanyssus except that it has a single long chelicera without chela while the former have two which are both armed with chelae. The gnathosome is so minute as to be absent, being completely masked by the enormous pair of pedipalps and the retractile chelicera. The mite has four pairs of legs each bearing a sucker xii i borne on a short unjointed stalk. The stalk and sucker together look like the distal end of a golf club, with the bulb facing posteriorly. Camelonyssus samburu (new genus and species) is also a blood sucking mite similar to C. golfer in having a single tubular needlelike chelicera which has no chela at the end. However, it is smaller in size than C. golfer although it has a large gnathosome which bears three pairs of long sharp spikes and a long protruding chelicera. Each pedipalp also bears a single spike which is similar to that of the capitulum. All legs have club-shaped suckers which contain a Y-shaped chitinous thickening and the unjointed stalk is short. The identity of the fourth mite species, the Baragoi 'Louse-mite', of which only one specimen with broken legs was available, has not yet been established except to say it is unlike any mite seen in the literature. Its body is shaped like a bowling pin with the smaller end being the falsehead. The mouthparts are complex and consist of five pairs. The first anterior/outer pair is shaped like pincers with curved bodies and needle-sharp ends. The second pair, which is also curved in conformity with and lies immediately behind the first one, is composed of a lateral half of thick solid chitin ending in a sharp point, while the medial half consists of vanes like in a birds' feather. The third pair resembles the second but is smaller and more blunter. The last two pairs are similar in structure and arrangement, being rod-shaped with sharp anterior ends. The other peculiarity of the mite is a pair of antenna-like structures at the rear end, enclosing a short pair of knob-like structures. All the five mite species caused similar lesions and responded favourably to treatment with 60 per cent Diazinon (Neocidal® Ciba-Geigy). The point prevalence rate of ticks on camels was ~00 per cent amongst the nomadic pastoralist herds throughout the study period. The sites commonly infested with ticks were the nostrils, sternal, inguinal and anal regions, eyelids, ears, tail and interdigital spaces. In camel calves nymphs were spread allover the body surface and in adults, along the backbone. On parts of the body covered by thick hairs, nymphs could only be detected on palpation. Evidence of tissue damage was common on predilection sites. This was due to tick bite and the resulting irritation and in some cases, infection and abscessation ensued. Ticks attached on the eyelids caused excessive irritation which resulted in marked lacrimation. One argasid or soft tick was identified as an Ornithodorus species and the following Ixodid or hard ticks were identified:-Amhlyomma gemma, Hyalomma dromedarii; H. truncatum; H. impeltatum, H. albiparmatum, H. detritum, H. marginatum rufipes, Rhipicephalus punctatus, R. pulchellus, and R. pravus .. Of all the ten tick species identified, male ticks were more abundant than female ticks. Very few engorged female ticks were encountered. Thick and thin blood smears examined from 426 camels were negative for tick-borne haemoparasites known to be endemic in other species of livestock in the area. There was total elimination of ticks from camels treated with two percent Cypermethrin high-cis (Ectopor®, Ciba-Geigy) at three weeks intervals. The prevalence of skin necrosis was 6.2 per cent and was usually found occurring in outbreaks affecting several animals at once. The lesions were first noted as firm and painful swellings which later burst leaving ulcers of raw flesh. The incidence of dermatomycoses was 4.3 per cent. Ringworm, dermatophilosis, sporotrichosis and other miscellaneous fungi were found and are described. The following microoganisms were identified: Aspergillus niger, A. nidulans, Candida albicans, Cladosporium species, Dermatophilus congolensis, Fusarium oxysporum, F. solani, Mucor species, Scopulariopsis species, Trichophyton species, and Trichosporon glabrata. Myiasis was not encountered in live animals but five camel carcasses examined at Isiolo abattoir were found to harbour the third-stage larvae of the camel nasal bot fly, - Cephalopina titillator, although the animals appeared in good health during antemortem inspection. Camel-flies, Hippobosca came/ina were found in all camel herds except those treated with Ectopor. Other flies were very common and numerous around the manyattas where they attacked all livestock species. Camels suffering or recovering from pox were particularly vulnerable and were severely disturbed by these flies. Recommendations based on the findings and conclusions of this study are given.