Acomys Dimidiatus Research Articles

Retinal neuroanatomy of two emerging model organisms, the spiny mouse (Acomys dimidiatus) and the Mongolian gerbil (Meriones unguiculatus)

Current research using animal models to investigate retinal cell biology and model retinal degenerative diseases largely utilize small mammals that are nocturnal and lack the ability to restore lost vision. In contrast, the Mongolian gerbil (Meriones) is a diurnal rodent with good photopic vision, and the spiny mouse (Acomys) is a small desert-dwelling rodent with remarkable regenerative capabilities. The goal of this study was to identify antibodies that detect retinal cell classes in Meriones and Acomys, and to describe the retinal anatomy of these two species in comparison to outbred laboratory mice (Mus musculus). Immunohistochemistry was performed on retinal sections with antibodies for various retinal cell types. Sections were imaged by light, fluorescence, and confocal microscopy. Cell density, morphology, and placement were compared between species qualitatively and quantitatively. Our analyses revealed a classic assembly of retinal cells in Meriones and Acomys, with a few deviations compared to Mus. Meriones displayed the highest density of cones and Acomys the lowest. A higher density of bipolar cell bodies in the proximal portion of the inner nuclear layer was observed in both Acomys and Meriones compared to Mus, and both species exhibited an increase in amacrine cell density compared to Mus. Our results provide a foundation for future research into the visual system adaptations of these interesting species.

Potentially Zoonotic Viruses in Wild Rodents, United Arab Emirates, 2019—A Pilot Study

The majority of emerging viral infectious diseases in humans originate from wildlife reservoirs, such as rodents and bats. We investigated a possible reservoir, namely wild gerbils and mice trapped in a desert reserve within the emirate of Dubai, United Arab Emirates (UAE). In total, 52 gerbils and 1 jird (Gerbillinae), 10 house mice (Mus musculus), and 1 Arabian spiny mouse (Acomys dimidiatus) were sampled. Oro-pharyngeal swabs, fecal samples, attached ticks, and organ samples (where available) were screened by (RT-q)PCR for the following viruses: Middle East respiratory syndrome-related coronavirus, Crimean-Congo hemorrhagic fever orthonairovirus, Alkhumra hemorrhagic fever virus, hantaviruses, Lymphocytic choriomeningitis mammarenavirus, Rustrela virus, poxviruses, flaviviruses, and herpesviruses. All of the samples were negative for all investigated viruses, except for herpesviruses: 19 gerbils (35.8%) and seven house mice (70.0%) were positive. The resulting sequences were only partly identical to sequences in GenBank. Phylogenetic analysis revealed three novel betaherpesviruses and four novel gammaherpesviruses. Interestingly, species identification of the positive gerbils resulted in eight individuals clustering in a separate clade, most closely related to Dipodillus campestris, the North African gerbil, indicating either the expansion of the geographic range of this species, or the existence of a closely related, yet undiscovered species in the UAE. In conclusion, we could not find evidence of persistence or shedding of potentially zoonotic viruses in the investigated rodent cohorts of limited sample size.

Additions to the chigger mite fauna (Acariformes: Trombiculidae) of Saudi Arabia, with the description of a new species

Collections of chigger mites from murid rodents were performed in two bordering provinces of southwestern Saudi Arabia, Al Bahah and ‘Asir. A total of 561 chiggers belonging to 19 species were collected in 2020 and 2021 from 54 rodents of two species, Acomys dimidiatus (Cretzchmar) and Mus musculus L. One new species is described: Odontacarus thesigeri n. sp. Five species are recorded in Saudi Arabia for the first time: Microtrombicula abyssinica (Radford, 1947), Microtrombicula felis (Vercammen-Grandjean, 1965), Microtrombicula saperoi (Radford, 1954), Schoengastiella hypoderma Vercammen-Grandjean, 1956, and Schoutedenichia originalis Kudryashova, 1976. Among them, M. abyssinica and M. saperoi, are re-described based on type specimens and new materials.

On heights and plains: How rodents from different habitats cope with three-dimensional environments?

Dwelling in a specific habitat requires adaptation to the habitat physical and biological properties in order to maximize fitness. Adaptations that are manifested in the organization of behavior in time and space reflect how the environment is perceived and utilized. Testing species from different habitats in the same laboratory environment can uncover the differences in their behavior and their adaptations to specific habitats. The question posed in this study is that of how two rodent species, one occupying flatlands (Tristram’s jird; Meriones tristrami) and the other occupying structured rocky habitats (common spiny mouse; Acomys dimidiatus), differ in the way that they explore the same three-dimensional laboratory environment. Individuals of these two species were introduced into an arena with a five-level ziggurat in the center, and their behavior was followed for 60 min. We found that both species preserved the typical spatiotemporal rodents’ behavior of establishing a home-base—a location that is a terminal from which they set out to explore the environment. However, the jirds, which live in flatlands, mainly travelled on the arena floor and the lower levels of the ziggurat; while, in contrast, the spiny mice, which live in rocky habitats and are used to climbing, mostly remained and travelled on the ziggurat, with some of them hardly descending to the arena floor. We suggest that the distinction in spatial behavior between the two species reflects their different motor abilities, different depth perception, and different umvelt (perceived world), in accordance with their different natural habitats.

Predictive modelling in paleoenvironmental reconstruction: The micromammals of Manot Cave, Israel

This paper describes the micromammalian remains and paleoenvironment of the Upper Paleolithic sequence of Manot Cave (46-34 ka), southern Levant. Micromammal remains were identified from Ahmarian (46-42 ka), Levantine Aurignacian (38-34 ka) and post-Levantine Aurignacian (34-33 ka) layers. To identify taphonomic agents, molar digestion was modelled for seven local raptor species, and model predictions were compared with observed digestion scores in the Manot Cave material. Raptor species differed significantly in molar digestion patterns, allowing us to identify Tyto alba as the bone accumulator in the Ahmarian and Post-Levantine Aurignacian units. Data were insufficient for species-level identification of the taphonomic agent in the Levantine Aurignacian. Günther's voles (Microtus guentheri) were dominant, though woodland species (Apodemus spp., Sciurus anomalus and Dryomys nitedula) also occurred through the entire sequence. Manot Cave furnished the first fossil record of the Eurasian snow vole (Chionomys nivalis) in the southern Levant during the Late Pleistocene and its first secure record of the water vole (Arvicola terrestris) outside the Hula Valley. Records of other taxa (Acomys dimidiatus and D. nitedula) provide the earliest occurrence datum in the region. Using counts of both identified specimens and distinct elements (lower first molars) we modelled paleoenvironmental conditions through both Weighted Averaging Partial Least Squares regression and a qualitative analysis considering niche preferences of species. Model predictions indicate the unexpectedly pronounced dominance of open habitats compared to present conditions near the cave, though the occurrence and abundance of woodland species also indicate some woodland expansion relative to the preceding Middle Paleolithic period. Combining statistical models and species niche considerations we show that the time span between the Ahmarian, Levantine Aurignacian and post-Levantine Aurignacian was marked by a clear-cut climatic oscillation to cooler and likely wetter conditions.

A survey on endoparasites in wild rodents ofthe Jaz Murian depression and adjacent areas, southeast of Iran.

In this survey, rodents and their endoparasites were investigated in the Jaz Murian depression and adjacent areas, southeast Iran. In total, 146 specimens of rodents belong to 13 species were trapped. In general, 10 different genera of endoparasites including 11 species were collected. The endoparasites were identified as follows: (1) Nematodes: Trichuris muris, Syphacia obvelata, Labiostomum sp., Labiostomum naimi, Mastrophorus muris, Aspicularis tetraptera and Heligmosomoides skrjabini, Physaloptera sp. (2) Cestodes: Choanotaenia sp., Raillietina sp., and Hymenolepis diminuta. Of 146 captured rodents, Tatera indica was found with high parasitic infestation (with 93% infested) comparing to Acomys dimidiatus (66%), Rattus rattus (50%), Meriones libycus (15%), Jaculus blanfordi (14%) and Mus musculus (8%) whereas, seven rodent species, Nesokia indica, Gerbillus nanus, Golunda ellioti, Calomyscus hotsoni, Apodemus witherbyi, Cricetulus migratorius and Microtus mystacinus were free from any parasitic infestation. Those six infested rodent species were collected from the center of the Jaz Murian depression, whereas seven non-infested rodents' species except N. indica and G. nanus live in the marginal ranges of the Jaz Murian depression, therefore, these species inhabiting the central parts were supposed to be more important from the health aspect. The species, Labiostomum naimi collected from A. dimidiatus is the first report of this species in rodents from Iran.

Long-term spatiotemporal stability and dynamic changes in helminth infracommunities of spiny mice (Acomys dimidiatus) in St. Katherine's Protectorate, Sinai, Egypt.

The importance of parasites as a selective force in host evolution is a topic of current interest. However, short-term ecological studies of host-parasite systems, on which such studies are usually based, provide only snap-shots of what may be dynamic systems. We report here on four surveys, carried out over a period of 12 years, of helminths of spiny mice (Acomys dimidiatus), the numerically dominant rodents inhabiting dry montane wadis in the Sinai Peninsula. With host age (age-dependent effects on prevalence and abundance were prominent) and sex (female bias in abundance in helminth diversity and in several taxa including Cestoda) taken into consideration, we focus on the relative importance of temporal and spatial effects on helminth infracommunities. We show that site of capture is the major determinant of prevalence and abundance of species (and higher taxa) contributing to helminth community structure, the only exceptions being Streptopharaus spp. and Dentostomella kuntzi. We provide evidence that most (notably the Spiruroidea, Protospirura muricola, Mastophorus muris and Gongylonema aegypti, but with exceptions among the Oxyuroidae, e.g. Syphacia minuta), show elements of temporal-site stability, with a rank order of measures among sites remaining similar over successive surveys. Hence, there are some elements of predictability in these systems.

Study of rodents’ fauna of the Jiroft and Anbarabad townships in southeast of Iran

In this study, rodent’s assemblages from Jiroft and Anbarabad townships in the southeast Iran, were studied. A total of 62 specimens were collected and identified during the period of June 2011 until September, 2012. The collected specimens consist of 10 species belonging to 10 genera and three families including: Muridae (Golunda ellioti, Acomys dimidiatus, Tatera indica, Nesokia indica, Meriones persicus, Mus musculus, Apodemus witherbyi, Rattus rattus), Cricetidae (Cricetulus migratorius), Ochotonidae (Ochotona rufescens). Standard external morphological and morphometric characteristics, including cranial and dental characters are given. The family Muridae with eight species, showed the highest diversity among the families represented here. Tatera indica showed the high frequency compare to other species examined in this study. Golunda ellioti Gray, 1837 and Acomys dimidiatus Cretzschmar, 1826 (Muridae, Rodentia) areas are recorded for the first time from southeast of Iran.

Description ofCandidatusBartonella fadhilae n. sp. andCandidatusBartonella sanaae n. sp. (Bartonellaceae) fromDipodillus dasyurusandSekeetamys calurus(Gerbillinae)from the Sinai Massif (Egypt)

Bartonella spp. are parasites of mammalian erythrocytes and endothelial cells, transmitted by blood-feeding arthropod ectoparasites. Different species of rodents may constitute the main hosts of Bartonella, including several zoonotic species of Bartonella. The aim of this study was to identify and compare Bartonella species and genotypes isolated from rodent hosts from the South Sinai, Egypt. Prevalence of Bartonella infection was assessed in rodents (837 Acomys dimidiatus, 73 Acomys russatus, 111 Dipodillus dasyurus, and 65 Sekeetamys calurus) trapped in 2000, 2004, 2008, and 2012 in four dry montane wadis around St. Katherine town in the Sinai Mountains. Total DNA was extracted from blood samples, and PCR amplification and sequencing of the Bartonella-specific 860-bp gene fragment of rpoB and the 810-bp gene fragment of gltA were used for molecular and phylogenetic analyses. The overall prevalence of Bartonella in rodents was 7.2%. Prevalence differed between host species, being 30.6%, 10.8%, 9.6%, and 3.6% in D. dasyurus, S. calurus, A. russatus, and A. dimidiatus, respectively. The phylogenetic analyses of six samples of Bartonella (five from D. dasyurus and one from S. calurus) based on a fragment of the rpoB gene, revealed the existence of two distinct genetic groups (with 95–96% reciprocal sequence identity), clustering with several unidentified isolates obtained earlier from the same rodent species, and distant from species that have already been described (90–92% of sequence identity to the closest match from the GenBank reference database). Thus, molecular and phylogenetic analyses led to the description of two species: Candidatus Bartonella fadhilae n. sp. and Candidatus Bartonella sanaae n. sp. The identification of their vectors and the medical significance of these species need further investigation.

Acomys dimidiatus (Rodentia: Muridae): Probable reservoir host of Leishmania major, southern Iran

Background: Rodents are the main reservoir hosts of zoonotic cutaneous leishmaniases (ZCLs) in different parts of Iran. Nonetheless, no evidence of natural infestation of Leishmania parasite has been reported from spiny mice Acomys dimidiatus (Rodentia: Muridae). Materials and Methods: Between March 2011 and March 2012, 62 wild rodents were captured and checked for leishmanial infestation of their livers and spleens using polymerase chain reaction in fourteen regions of Darab district in Fars province, southern Iran. Results: Overall, 62 rodents consisting of 42 Tatera indica, 6 Meriones libycus, 5 Meriones persicus, 5 Mus musculus, and 4 A. dimidiatus were identified. Infestation to Leishmania major was confirmed in all the captured species of rodents: T. indica (23.8%), M. libycus (50%), A. dimidiatus (50%), M. persicus (20%), and M. musculus (20%). Conclusions:T. indica was the reservoir host of L. major in this focus of ZCL. Moreover, M. libycus and M. persicus had a remarkable role in the maintenance of the parasite. A. dimidiatus was also introduced as a new probable reservoir host of L. major for the first time. Yet, the role of this species in the maintenance, transmission, and epidemiological cycle of ZCL needs more specific researches.

Altitudinal variation in the diversity and structure of the desert rodent community from Jebel Al Jais, United Arab Emirates

In arid areas where organisms are subjected to environmental extremes, ecological communities are simple and provide useful models for studying community organisation. We used capture, mark and release methods between November 2014 and May 2015 to assess the rodent community in the Hajar Mountains of Ras Al Khaima along an altitudinal gradient from 460 m to 1650 m. We captured three rodent species; Arabian Spiny Mouse, Acomys dimidiatus, Wagner’s Gerbil, Gerbillus dasyurus and a Black Rat, Rattus rattus (the latter only represented by a single specimen on one occasion). The structure of rodent communities varied altitudinally with the relative abundance of Spiny Mice decreasing and Wagner’s Gerbils increasing with altitude.

Long-term spatiotemporal stability and dynamic changes in the haemoparasite community of spiny mice (Acomys dimidiatus) in four montane wadis in the St. Katherine Protectorate, Sinai, Egypt.

BackgroundLong-term field studies of parasite communities are rare but provide a powerful insight into the ecological processes shaping host-parasite interactions. The aim of our study was to monitor long-term trends in the haemoparasite communities of spiny mice (Acomys dimidiatus) and to identify the principal factors responsible for changes over a 12 year period.MethodsTo this end we sampled four semi-isolated populations of mice (n = 835) in 2000, 2004, 2008 and 2012 in four dry montane valleys (wadis) located in the Sinai Massif, Egypt.ResultsOverall 76.2 % of spiny mice carried at least one of the five haemoparasite genera (Babesia, Bartonella, Haemobartonella, Hepatozoon, Trypanosoma) recorded in the study. Prevalence of haemoparasites varied significantly between the sites with the highest overall prevalence in Wadi Tlah and the lowest in W. El Arbaein, and this changed significantly with time. In the first two surveys there was little change in prevalence, but by 2008, when the first signs of a deepening drought in the region had become apparent, prevalence began to drift downwards, and by 2012 prevalence had fallen to the lowest values recorded from all four sites over the entire 12-year period. The overall mean species richness was 1.2 ± 0.03, which peaked in 2004 and then dropped by more than 50 % by 2012. Species richness was highest among mice from Wadi Tlah and peaked in age class 2 mice (young adults). Site was the most significant factor affecting the prevalence of individual parasite species, with Trypanosoma acomys and Hepatozoon sp. occurring mainly in two wadis (W. Tlah & W. Gharaba). In four of the five genera recorded in the study we observed a significant drop in prevalence or/and abundance since 2004, the exception being Hepatozoon sp.ConclusionsDuring the 12-year-long period of study in the Sinai, we observed dynamic changes and possibly even cycles of prevalence and abundance of infections which differed depending on parasite species. Although the exact reasons cannot be identified at this time, we hypothesize that the effects of a 15-year-long scarcity of rainfall in the local environment and a fall in host densities over the period of study may have been responsible for a drop in transmission rates, possibly by a negative impact on vector survival.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1471-z) contains supplementary material, which is available to authorized users.

The distribution of mucous secreting cells in the gastrointestinal tracts of three small rodents from Saudi Arabia: Acomys dimidiatus, Meriones rex and Meriones libycus

The proportion of mucin phenotypes (which form the protective biofilm of the gastrointestinal tract) differs between intestinal regions. This study examines the distribution of mucin secreting cells in the gastrointestinal tracts of the Eastern spiny mouse (Acomys dimidiatus), King jird (Meriones rex) and Libyan jird (Meriones libycus), which inhabit the dry and hot deserts of Saudi Arabia. Intestinal tract samples were processed to wax and tissue sections stained with Alcian Blue-Periodic Acid Schiff (AB-PAS) and High Iron Diamine-Alcian Blue (HID-AB) in order to determine different mucin phenotypes by quantitative analysis. Mixed mucin secreting cells (combined neutral and acid) was the predominant mucin secreting cell type observed throughout the gastrointestinal tract in all species. Acid mucin secreting goblet cells were mainly located in the colon. A. dimidiatus presented with significantly more total sialo than sulfomucin secreting cells while the opposite was true for both Meriones species. The distribution of mucin secreting cells is therefore similar to previously reported results for small mammals not living under arid conditions.

Intraspecific and interspecific genetic variation of Gongylonema pulchrum and two rodent Gongylonema spp. (G. aegypti and G. neoplasticum), with the proposal of G. nepalensis n. sp. for the isolate in water buffaloes from Nepal.

The gullet worm (Gongylonema pulchrum) has been recorded from a variety of mammals worldwide. In an earlier study, we demonstrated two separate transmission cycles in cattle (Bos taurus) and wild mammals in Japan based on nucleotide sequences of the ribosomal RNA gene (rDNA) and cytochrome c oxidase subunit I (cox-1) region of mitochondrial DNA of multiple isolates of different origins. Our earlier study additionally demonstrated two major cox-1 haplotypes of G. pulchrum prevalent in cattle in Japan. In the present study, we collected G. pulchrum from cattle and goats (Capra hircus) in Alashan League, Inner Mongolia, China; Gongylonema aegypti from spiny mice (Acomys dimidiatus) in the Sinai Peninsula, Egypt; and Gongylonema neoplasticum from a black rat (Rattus rattus) in Okinawa Island, Japan, to analyze their genetic relationships with G. pulchrum in Japan. The gullet worms from Alashan League had almost identical rDNA nucleotide sequences and two cox-1 haplotypes as seen in G. pulchrum from the cattle in Japan. The two rodent Gongylonema spp. had distinct rDNA nucleotide sequences compared with those of G. pulchrum; only the 18S and 5.8S rDNA sequences showed high identities at 97.2-98.7%, while the remaining sequences were less than 75% identical. The 18S, 5.8S, and 28S rDNA sequences of the two rodent Gongylonema spp. showed nucleotide identities of 99.8% (1811/1814), 100% (158/158), and 98.9% (3550/3590), respectively. The cox-1 regions showed 91.6% (338/369)-92.1% (340/369) identities, with completely identical amino acid sequences. The genetic diversities of three distinct Gongylonema spp. and their possible intraspecific genetic variation may allow us to resolve the taxonomic position of Gongylonema spp. which display few obvious morphological differences from their congeners. Consequently, the Gongylonema isolate from water buffaloes (Bubalus bubalis) in Nepal reported in our previous study is concluded to be a new species, and Gongylonema nepalensis n. sp. is erected for it.

Seasonal reproduction in the Arabian spiny mouse, Acomys dimidiatus (Rodentia: Muridae) from Saudi Arabia: The role of rainfall and temperature

In deserts where unpredictable rainfall arises and a large variation in temperature occurs, this poses severe energetic and water related constraints on reproduction in small mammals and makes the use of photoperiod as cue for reproduction unreliable. In the present study, the gonad morphometrics, gonadal histology and endocrine profiles of the Arabian spiny mouse (Acomys dimidiatus) were studied over 12 consecutive months in a field population from western Saudi Arabia in an attempt to assess the seasonality of reproduction and gain insights into the environmental cues that may trigger reproduction in this species. Although sperm was present throughout the year, most reproductive parameters exhibited a seasonal pattern with a minimum in winter in both sexes and pregnancies were observed from spring to autumn. Whereas testes volume, the number of corpora lutea and progesterone levels were correlated with temperature, all other reproductive parameters were correlated with rainfall. Thus, it appears that A. dimidiatus ceases to breed during winter and uses rainfall as an environmental cue to initiate reproduction in the study area. However, the species appears to have the ability to reproduce throughout the year, if favourable conditions arise.

Babesia behnkei sp. nov., a novel Babesia species infecting isolated populations of Wagner's gerbil, Dipodillus dasyurus, from the Sinai Mountains, Egypt.

BackgroundAlthough a number of new species of Babesia/Theileria have been described recently, there are still relatively few reports of species from Africa. In this study based on the evaluation of morphology and phylogenetic relationships, we describe a novel species from Wagner’s gerbil, Babesia behnkei n. sp.MethodsRodents (n = 1021) were sampled in four montane valleys (wadies) in 2000, 2004, 2008 and 2012 in the Sinai Mountains, Egypt. The overall prevalence of Babesia spp. was highest in the Wagner’s gerbil (Dipodillus dasyurus; 38.7%) in comparison to the prevalence in the spiny mice species, Acomys dimidiatus and A. russatus. Morphological investigations were conducted for the comparison of trophozoites of the novel species of Babesia with the B. microti King’s 67 reference strain. Thirty-two isolates derived from D. dasyurus over a 9 year period (2004-2012) from two wadies (29 isolates from Wadi Gebel and 3 from Wadi El-Arbaein) were investigated by microscopic, molecular and phylogenetic analysis. A near-full-length sequence of the 18S rRNA gene and the second internal transcribed spacer (ITS2) region were amplified, sequenced and used for the construction of phylogenetic trees.ResultsA novel species of Babesia was identified in two isolated populations of D. dasyurus. Phylogenetic analysis of 18S rDNA and ITS2 sequences revealed that B. behnkei n. sp. is most closely related to B. lengau from cheetahs from South Africa and to Nearctic species found only in North America (the pathogenic B. duncani and B. conradae) and that it is more distant to the cosmopolitan rodent parasite B. microti. Trophozoites of B. behnkei were smaller and less polymorphic than trophozoites of B. microti.ConclusionBabesia behnkei n. sp. is a novel species of the ‘Duncani group’ maintained in isolated populations of Dipodillus dasyurus occurring in the Sinai Mountains of Egypt.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-014-0572-9) contains supplementary material, which is available to authorized users.

Occurrence of ectoparasitic arthropods associated with rodents in Hail region northern Saudi Arabia.

Ectoparasitic arthropods are a diverse element of the Saudi fauna. Due to this, a survey of ectoparasites associated with rodents was conducted as a preliminary study in five districts of Hail region of northern Saudi Arabia for the first time. Ectoparasites extracted from 750 rodents were sampled and identified by recording their frequency of appearance. Results revealed that 1,287 ectoparasites infested 316 of the captured rodent hosts. These ectoparasites parasitized on four species of rodents including three species of rats Rattus rattus rattus, Rattus rattus frugivorus, and Rattus rattus alexandrinus and one species of mouse Acomys dimidiatus (Rodentia: Muridae). The ectoparasites belong to four different groups: ticks, fleas, lice, and mites. Ticks were the highest in the number, while fleas were the lowest among all the extracted ectoparasite groups. The collected ectoparasitic arthropods consisted of seven species. Ticks were of two species: Rhipicephalus turanicus and Rhipicephalus sanguineus (Acari: Ixodidae), fleas were of two species: Xenopsylla cheopis and Xenopsyllus conformis mycerini (Siphonaptera: Pulicidae), lice was a single species: Polyplax serrata (Anoplura: Hoplopleuridae), and mites were of two species: Laelaps nuttali and Laelaps echidninus (Mesostigmata: Laelapidae). The findings of the study showed that the intensity of infestation was varied between rodent host sexes, wherein females had the highest rate of parasitic infestation, and the parasitic index of appearance was very high for one group of parasites (i.e., ticks). The parasitic prevalence was 42.13 % on rodents, and mites were the most prevalent parasite species. Overall, this study was carried out to establish baseline data for ectoparasite-infested rodents in Hail region, Saudi Arabia, and may help for appropriate planning to control zoonotic diseases in this area.

The comparative gastrointestinal morphology of five species of muroid rodents found in Saudi Arabia

Meriones rex (King jird), Meriones libycus (Libyan jird), Acomys dimidiatus (Eastern spiny mouse), Acomys cahirinus (Egyptian spiny mouse), and Dipodillus dasyurus (Wagner's dipodil) are five species of small rodents of the superfamily Muroidea with distributions in Eastern Africa, Egypt, and the desert regions of the Arabian Peninsula. Water is scarce in these regions and may result in relatively low-digestible food. The aim of the present study is to describe and compare the gastrointestinal tract morphology and morphometry of these five species in order to elucidate whether morphology is influenced by phylogeny or dietary preference. Each segment of the gastrointestinal tract of each species was macroscopically examined and the length and basal surface area of each segment was measured. Standard histologic procedures were performed to determine a surface enlargement factor to determine the mucosal luminal surface area. A unilocular-hemiglandular stomach was observed in all the species examined. The caeca of all the species were long and arranged into a loose spiral toward the caecal tip with the ileocaecal and caeco-colic openings positioned close together. Two rows of oblique folds could be observed in the proximal colon of all species except in D. dasyurus which had longitudinal folds. Morphometric analysis showed the largest stomach in A. cahirinus and the largest caecum and colon in M. libycus. All the species can be grouped in the family Muridae in two subfamilies and similarities were observed including the hemiglandular stomach and relatively large caecum. It could be concluded that phylogeny plays an important role in determining gastrointestinal morphology while diet plays a subordinate role in the desert rodents in the present study.

Babesia behnkei sp. nov., a novel Babesia species infecting isolated populations of Wagner¿s gerbil, Dipodillus dasyurus, from the Sinai Mountains, Egypt

Although a number of new species of Babesia/Theileria have been described recently, there are still relatively few reports of species from Africa. In this study based on the evaluation of morphology and phylogenetic relationships, we describe a novel species from Wagner’s gerbil, Babesia behnkei n. sp. Rodents (n = 1021) were sampled in four montane valleys (wadies) in 2000, 2004, 2008 and 2012 in the Sinai Mountains, Egypt. The overall prevalence of Babesia spp. was highest in the Wagner’s gerbil (Dipodillus dasyurus; 38.7%) in comparison to the prevalence in the spiny mice species, Acomys dimidiatus and A. russatus. Morphological investigations were conducted for the comparison of trophozoites of the novel species of Babesia with the B. microti King’s 67 reference strain. Thirty-two isolates derived from D. dasyurus over a 9 year period (2004-2012) from two wadies (29 isolates from Wadi Gebel and 3 from Wadi El-Arbaein) were investigated by microscopic, molecular and phylogenetic analysis. A near-full-length sequence of the 18S rRNA gene and the second internal transcribed spacer (ITS2) region were amplified, sequenced and used for the construction of phylogenetic trees. A novel species of Babesia was identified in two isolated populations of D. dasyurus. Phylogenetic analysis of 18S rDNA and ITS2 sequences revealed that B. behnkei n. sp. is most closely related to B. lengau from cheetahs from South Africa and to Nearctic species found only in North America (the pathogenic B. duncani and B. conradae) and that it is more distant to the cosmopolitan rodent parasite B. microti. Trophozoites of B. behnkei were smaller and less polymorphic than trophozoites of B. microti. Babesia behnkei n. sp. is a novel species of the ‘Duncani group’ maintained in isolated populations of Dipodillus dasyurus occurring in the Sinai Mountains of Egypt.

Down in the Wadi: The locomotory activity rhythm of the Arabian spiny mouse, Acomys dimidiatus from the Arabian Peninsula

The circadian rhythm of locomotory activity in the Arabian spiny mouse, a desert living species, was investigated under controlled laboratory conditions. Ten individuals were subjected to successive light cycles. When subjected to a 12L:12D light cycle, locomotor activity was confined mainly to the dark phase (mean 94.2% ± 1.6%). During a period of constant darkness (DD), all animals expressed free running rhythms of locomotor activity (mean 23h49 ± 0h04). Following a second LD cycle, the light and dark phases were inversed (12D:12L). Activity shifted with the lights and was masked during the light phase, re-entrainment was rather slow (up to 10 days). The effect of varying ambient temperature (20–35 °C) on the locomotor activity under a 12L:12D cycle revealed that temperature had no distinct effect on the level of locomotor activity. When the dark component of the day was lengthened to 8L:16D, the mean percentage of activity during the dark increased to 96.0 ± 0.8%, while a significant decrease in night time activity was observed when the dark phase length was decreased to 16L:8D (78.29 ± 2.52%). The Arabian spiny mouse therefore behaves as other desert dwelling rodents and can be described as truly nocturnal.