Babesia infection in rodents trapped in Riyadh Region, Saudi Arabia, with a general discussion.

Species of Babesia are intraerythrocytic protozoal parasites of many species of mammalians in all parts of the world where the tick-vectors are found. Babesiosis or piroplasmosis causes considerable damage to the livestock and other animals. Human babesiosis has been documented in many countries. Consequently, babesiosis is a zoonotic disease of medical, veterinary and economic importance. In this study, a total of 310 rodents of different species were trapped from different areas in Riyadh Region, Saudi Arabia. These rodents were; Rattus rattus (142), R. norvegicus (24), Mus musculus (8), Meriones crassus (56), Jaculus jaculus (16), Gerbillus cheesmani (50) and Acomys c. dimidiatus (14). Natural Babesia infection was parasitologically detected in 95 of them (30.65%). The highest infection rate was among R. rattus (34.5%). The lowest rate was among G. cheesmani (20%). None of the M. musculus was infected. Since most of these rodents are commensal ie living in close contact with man, a general discussion on the pathogenesis, immunity and diagnosis was given.

Investigation on the presence of Leishmania natural infection and antibodies among rodents in Riyadh, Saudi Arabia.

Leishmaniases whether cutaneous and/or visceral are one of the public health problems in nearly all countries of the Eastern Mediterranean Region. The prevalence and the incidence are increasing. Control of the animal reservoir hosts in zoonotic forms is one of the best means of measures against leishmaniasis. This paper aimed to screen rodents for their role as reservoir for leishmaniasis. Natural Leishmania infection was detected in one Meriones crassus out of 3 which had cutaneous lesions. The lesion present on Gerbillus cheesmani was negative for amastigotes. Anti-leishmanial antibodies as detected by indirect haemagglutination tests (I.H.A.T.) showed reaction among the seven species of the trapped rodents. However, by interpretation of the diagnostic value of I.H.A. only three M. crassus (3/512) and one Gerbillus cheesmani (1/256) gave seropositive reactions. The whole results were discussed.

Studies on the interrelation between rodents and their ectoparasitic acarines in Riyadh region, Saudi Arabia.

The ectoparasitic acarines of commensal and wild rodents collected from various areas in Riyadh Region were four species of mites (Laelaps nutalli, Ornythonyssus bacoti, Cheyletus eruditus and Articholaelaps glasgowi), and two species of ticks. (Immature stages) Rhipicephalus spp. and Hyalomma spp. In urban areas the highest infestation rate by mites was 49.9% on Rattus rattus followed by 18.5% on Rattus norvegicus. The highest rat-mite index was 2.3 on R. rattus followed by 1.3 on R. norvegicus and 0.1 on Mus musculus. In semiarid areas, the highest rat-mite index was 2.1 on Gerbillus spp. followed by 1.7 on Meriones spp., 1.6 on Jaculus jaculus and 0.9 on Acomys dimidiatus. The highest infestation rate by mites was on Meriones spp. followed by Gerbillus spp. and then A. dimidiatus.

Studies on the ectoparasites (fleas and lice) on rodents in Riyadh and its surroundings, Saudi Arabia.

A survey was conducted on rodents from the Riyadh City and surroundings. Two species of fleas, Xenopsylla cheopis and Ctenocephalides felis felis together with Polyplax spinulosa were collected. The highest infestation rate by both fleas occurred on Rattus rattus followed by Rattus norvegicus and Mus musculus. Females of R. rattus and R. norvegicus were more infested by fleas than males. On the other hand, Meriones spp., Gerbillus spp., Jaculus jaculus and Acomys dimidiatus were infested with X. cheopis and C.f. felis. The highest infestation rate by fleas occurred on Gerbillus spp. followed by Meriones spp.

Some histological studies on the oesophagus of the Nile fox (Vulpes Vulpes aegyptiaca).

This work was carried out on eight foxes. The results showed that, the lining epithelium is of stratified squamous non-keratinized type which abruptly changed into glandular simple columnar epithelium. The lamina muscularis mucosa is in the form of small scattered strands of smooth muscle fibers in the cranial and middle parts and formed a continuous layer in the caudal part near the cardia. The submucosal glands are well developed and extend along the whole length of the oesophagus till reached slightly below the cardiac region of the stomach. They were mainly of mucous acini with few serous one. The glandular mucous acini were alcianophilic. The tunica muscularis externa is of skeletal muscles along the whole length of the oesophagus except just before the cardia by 1.5 cm, the tunica muscularis are formed from mixture of smooth and skeletal muscle fibres.