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PubMed2000

Long-branch attraction phenomenon and the impact of among-site rate variation on rodent phylogeny.

The phylogenetic relationships among major lineages of rodents is one of the issues most debated by both paleontologists and molecular biologists. In the present study, we have analyzed all complete mammalian mitochondrial genomes available in the databases, including five rodent species (rat, mouse, dormouse, squirrel and guinea-pig). Phylogenetic analyses were performed on H-strand amino acid sequences by means of maximum-likelihood and on H-strand protein-coding and ribosomal genes by means of distance methods. Also, log-likelihood ratio tests were applied to different tree topologies under the assumption of rodent monophyly, paraphyly or polyphyly. The analyses significantly rejected rodent monophyly and showed the existence of two differentiated clades, one containing non-murids (dormouse, squirrel and guinea-pig) and the other containing murids (rat and mouse). Long-branch attraction between murids and the outgroups could not be responsible for the existence of two different rodent clades, as no significant differences in evolutionary rate have been observed, except in the case of the squirrel, which shows a lower rate. The impact of among-site rate variation models on the phylogeny of rodents has been evaluated using the gamma distribution model. Results have shown that relationships among rodents remained unchanged, and the general topology of the tree was not affected, even though some branches were not properly resolved, most likely due to a lack of fit between estimated and real rate heterogeneity parameters.

Animals↗
PubMed2002

Pika and vole mitochondrial genomes increase support for both rodent monophyly and glires.

Complete mitochondrial genomes are reported for a pika (Ochotona collaris) and a vole (Volemys kikuchii) then analysed together with 35 other mitochondrial genomes from mammals. With standard phylogenetic methods the pika joins with the other lagomorph (rabbit) and the vole with the other murid rodents (rat and mouse). In addition, with hedgehog excluded, the seven rodent genomes consistently form a homogeneous group in the unrooted placental tree. Except for uncertainty of the position of tree shrew, the clade Glires (monophyletic rodents plus lagomorphs) is consistently found. The unrooted tree obtained by ProtML (Protein Maximum Likelihood, a program in MOLPHY) is compatible with a reclassification of mammals [Syst. Biol. 48, 1-5 (1999)] which is also supported by other recent studies. However, when this tree is rooted with marsupials plus platypus, the outgroup often joins the lineage leading to the three murid rodents, so the rodents are no longer monophyletic. Apart from misplacing the root, the presence of the outgroups also distorts other parts of the unrooted tree. Either constraining the tree to maintain rodents monophyletic, or omitting murids, maintains the ingroup tree and sees the outgroup join on the edge to Xenarthra, to Afrotheria, or to these two groups together. This emphasises the importance of carrying out both an unrooted and a rooted analysis. It is known from cancer research that murid rodents have reduced activity in some DNA repair mechanisms and this alters their substitution pattern - this may be the case for mitochnodrial DNA as well. Comparing nucleotide compositions may identify taxa that differ in aspects of their DNA repair mechanisms.

Animals↗
PubMed1999

Skin and soft tissue artifacts due to postmortem damage caused by rodents.

Five cases of postmortem bite-injuries inflicted by rodents are presented (five males between 41 and 89 years; three cases caused by mice, one case by rats, one case of possible mixed rodent activity by rats and mice). The study presents a spectrum of phenomenological aspects of postmortem artifacts due to rodent activity to fresh skin and soft tissue: the majority of the injuries have a circular appearance. The wound margins are finely serrated with irregular edges and circumscribed 1-2 mm intervals within, partly showing protruding indentations up to 5 mm. Distinct parallel cutaneous lacerations deriving from the biting action of the upper and lower pairs of the rodents incisors are diagnostic for tooth marks of rodent origin but cannot always be found. No claw-induced damage can be found in the skin beyond the wound margins. Areas involved in the present study were: exposed and unprotected parts of the body, such as eyelids, nose and mouth (representing moist parts of the face); and the back of the hands. Postmortem rodent activity may occasionally be expected on clothed and therefore protected parts of the body. The phenomenon of postmortem rodent activity to human bodies can be found indoors especially under circumstances of low socioeconomic settings; outdoors this finding is particularly observed among fatalities among homeless people.

Adult↗
PubMed2002

cDNA nucleotide sequence encoding the ZPC protein of Australian hydromyine rodents: a novel sequence of the putative sperm-combining site within the family Muridae.

This comparative study of the cDNA sequence of the zona pellucida C (ZPC) glycoprotein in murid rodents focuses on the nucleotide and amino acid sequence of the putative sperm-combining site. We ask the question: Has divergence evolved in the nucleotide sequence of ZPC in the murid rodents of Australia? Using RT-PCR and (RACE) PCR, the complete cDNA coding region of ZPC in the Australian hydromyine rodents Notomys alexis and Pseudomys australis, and a partial cDNA sequence from a third hydromyine rodent, Hydromys chrysogaster, has been determined. Comparison between the cDNA sequences of the hydromyine rodents reveals that the level of amino acid sequence identity between N. alexis and P. australis is 96%, whereas that between the two species of hydromyine rodents and M. musculus and R. norvegicus is 88% and 87% respectively. Despite being reproductively isolated from each other, the three species of hydromyine rodents have a 100% level of amino acid sequence identity at the putative sperm-combining site. This finding does not support the view that this site is under positive selective pressure. The sequence data obtained in this study may have important conservation implications for the dissemination of immunocontraception directed against M. musculus using ZPC antibodies.

Amino Acid Sequence↗
PubMed1988

Sound localization in a predatory rodent, the northern grasshopper mouse (Onychomys leucogaster).

A comparison of the ability of mammals to localize sound revealed that among the animals examined to date, none of the rodents have been able to localize as accurately as the carnivores. Because all of these rodents are prey animals, the question arises as to whether their poor localization acuity is a phyletic trait of Rodentia or whether it is a trait common to prey species that may be under less selective pressure than predators to localize sound accurately. To answer this question, sound localization acuity was determined in a species that is both predatory and a rodent, the northern grasshopper mouse. Localization thresholds for a single 100-ms noise burst were determined for three grasshopper mice using a conditioned avoidance procedure. Their 50% discrimination threshold of 19 degrees is larger than that of any of the previously tested carnivores and well within the range of other rodents. However, calculations of the binaural sound localization cues available to rodents (based on their head size) suggest that the grasshopper mouse may make more efficient use of the available locus cues than other rodents. Thus, although the grasshopper mouse cannot localize as accurately as carnivores, it appears to be more accurate than predicted for a nonpredatory rodent of its size.

Animals↗
PubMed1994

Primitive fossil rodent from Inner Mongolia and its implications for mammalian phylogeny.

The evolutionary origin of rodents is obscured by the group's sudden and highly transformed first appearance in the fossil record in the latest Paleocene. We report here the discovery of nearly complete dental remains of an extraordinary new primitive rodent from strata of transitional Paleocene-Eocene age in Inner Mongolia, China. The strikingly conservative morphological features of this taxon, Tribosphenomys minutus, gen. et sp. nov., substantially modify previous ideas about the ancestral rodent morphotype, which in turn has important implications for understanding the origin of rodents and their relationship to other eutherian mammals. This new fossil, in conjunction with recent morphological and molecular evidence confirming rodent monophyly, indicates the need for a reassessment of phylogenetic affinities among gliriform eutherians. Our results indicate a sister-group position of the new taxon to other rodents, and support the alliance of lagomorphs (rabbits) and rodents (cohort Glires). They also suggest that paraphyly of an extinct assemblage, the 'Eurymylidae', and reveal an unexpectedly complex pattern of character evolution near the ancestry of Rodentia.

Animals↗
PubMed1990

Subadult Ixodes ricinus (Acari: Ixodidae) on rodents in Berlin, West Germany.

To identify hosts that may serve as reservoirs for the agent of Lyme disease in Central Europe, we determined whether Ixodes ricinus L. feed most frequently on certain rodents and whether the abundance of these hosts corresponds to the season of feeding activity of the tick in four sites in Berlin, Federal Republic of Germany. In addition, we correlated abundance of I. ricinus with that of particular rodent hosts. Two small rodents were more abundant than any others; a mouse, Apodemus flavicollis, predominated in a wooded site and a vole, Clethrionomys glareolus, in three brush- or grass-covered sites. The tick was most abundant in the mouse-infested site. Although A. flavicollis comprised only about a third of rodents collected, nearly 60% of all such rodent parasitizing I. ricinus fed on this mouse. These ticks were more abundant on mice than voles in each of the study sites and throughout the year, and more larvae fed on these rodents than did nymphs. Although larval as well as nymphal I. ricinus are most abundant during midsummer, they feed on rodents from April through October. Taken together, these observations suggest A. flavicollis as a potentially important reservoir host for I. ricinus-borne infections.

Animals↗
PubMed1999

The duration of non-rodent toxicity studies for pharmaceuticals. International Conference on Harmonication (ICH).

At the present time, there are no uniform standards for the duration of non-rodent chronic toxicity studies. The European Union (EU) requires a 6-month non-rodent study. In Japan, a 6-month study is sufficient for most, but not all, compounds. The U.S. Food and Drug Administration (FDA) maintains its standard duration of 12 months for non-rodents, with 6-month studies accepted for some clinical indications on a case-by-case basis. To achieve harmonization on the duration of non-rodent toxicity studies, each member regulatory region (EU, U.S., and Japan) of the International Conference on Harmonization (ICH) collected non-rodent studies with significant new toxicological findings that had occurred after 6 months. An ICH expert working group was organized that included representatives from the regulatory authorities of each ICH region, to jointly review all available case studies for the purpose of arriving at a consensus on the best duration time for non-rodent toxicity studies. Eighteen case studies were identified and evaluated (16 original cases plus 2 additional FDA cases); most of the toxicities identified fell into the following categories: (1) toxicities identified at 6 months; (2) toxicities observed at 12 months, which were absent or considered isolated and not noteworthy findings at 6 months; (3) drug-related deaths or morbidity that occurred between 6 and 12 months, with a pattern of toxicity that permitted the interpolation of findings to an intermediate interval between 6 and 12 months; and (4) a shift in the dose response for toxicity with increasing duration of drug exposure. Of the 18 cases evaluated, 11 supported a study-duration of 9-12 months, 4 supported a duration of 12 months, and the 3 remaining cases indicated that a 6-month study would be adequate. The working group concluded that there was sufficient evidence to support a harmonized 9-month duration for non-rodent toxicity studies, which would be applicable for most categories of pharmaceuticals.

Animals↗
PubMed2004

Identification of evolutionary hotspots in the rodent genomes.

We describe a whole-genome comparative analysis of the human, mouse, and rat genomes to describe the average substitution patterns of four genomic regions: ancient repeats, rodent-specific DNA, exons, and conserved (coding and noncoding) regions, and to identify rodent evolutionary hotspots. In all types of regions, except the rodent-specific DNA, the rat branch is slightly longer than the mouse branch. Moreover, the mouse-rat distance is longer in the rodent-specific DNA than in the ancient repeats. Analysis of individual conserved regions with different substitution models yielded the conclusion that the Jukes-Cantor model is inadequate, and the Hasegawa-Kishino-Yano model is almost as good as the REV model. Using human as an outgroup, we identified 5055 evolutionary hotspots, which are highly conserved subalignment blocks (each consisting of at least 100 aligned sites and a small fraction of gaps) with a large and statistically significant difference in the branch lengths of the rodent species. The cutoffs used to identify the hotspots are partially based on estimates of the average rates of substitution. The fractions of hotspots overlapping with the rodent RefSeq genes, RefSeq exons, and ESTs are all higher than expected. Still, more than half of the hotspots lie in noncoding regions of the mouse genome. We believe that the hotspots represent biologically interesting regions in the rodent genomes.

Animals↗
PubMed1993

Human and rodent Alzheimer beta-amyloid peptides acquire distinct conformations in membrane-mimicking solvents.

The major constituent of senile plaques (one of the hallmark lesions of Alzheimer's disease) is a 42(43)-amino-acid polypeptide, termed the A4 or beta-amyloid peptide. The beta-amyloid peptide or A4 is derived from one or more larger beta-amyloid precursor proteins. The precursor protein from whence the A4 peptide is derived is highly conserved throughout evolution, and humans, monkeys, dogs, and bears develop brain deposits of A4 peptide in amyloid fibrils. However, similar accumulations of A4 amyloid are negligible in the brains of rats and mice for reasons that remain unexplored. Notably, the A4 sequence of rodents, deduced from the cDNA clones, differs only in three amino acids from the A4 isolated from the brain of humans. Hence, these differences could account for the inability of rodents to develop Alzheimer-like A4 amyloid plaques. To test this hypothesis directly, using physical and chemical model systems, we synthesized, purified, and characterized A4 peptides corresponding to the human and rodent sequences. Circular dichroic and Fourier-transform infrared spectroscopy were used with various membrane-mimicking solvents, different peptide concentrations, and variable pH to identify those environmental conditions that promoted beta-pleated sheet formation of the human versus rodent A4. At an intermediate alkaline pH (< or = 10), the rodent peptide has more beta-pleated sheet structure than the human sequence. The beta-pleated sheets for both peptides could be eliminated at very high pH (> or = 12). The amount of the beta-structure increased in an octyl glucoside solution, compared to that found in SDS, as well as in several of the other solutions tested here. This suggests that particles originated from prior membrane damage may play a role in the stabilization of beta-pleated sheets with subsequent formation of amyloid deposits. Finally, we found that higher beta-pleated sheet content was observed for the rodent sequences in acetonitrile/water mixtures. In contrast, more beta-pleated sheets were detected with the human A4 in trifluoroethanol/water mixtures at neutral pH. Remarkably, at relatively low peptide concentrations, only the human sequences assumed an extended secondary structure. These data suggest that subtle inter-species amino-acid differences may account for the inability of the rodent peptide to form amyloid fibrils in situ.

Amino Acid Sequence↗
PubMed1995

[The use of polymerase chain reaction method for the detection of Rickettsia tsutsugamushi in wild rodents].

We studied the applicability of polymerase chain reaction (PCR) method for the detection of R. tsutsugamushi in wild rodents. The PCR method which amplified the gene coding for the group-specific antigen of R. tsutsugamushi was used in this study. Specific PCR products (88 bp) were obtained with the DNAs from three reference strains (Gilliam, Karp, and Kato) and two cell culture adapted field isolates (KN-1 and GJ-1). The minimum number detectable by the PCR method was estimated to be 1.3 copies of rickettsial genome. In a study with experimentally infected mice, the PCR method could detect rickettsial DNA in one of two infected mice at four months after inoculation. Thereafter, fifty five wild rodents were captured in five areas of Okayama Prefecture, and R. tsutsugamushi DNA was detected, by the PCR method, by amplifying DNA from the spleen of each rodent. The rickettsia was also isolated from the same rodents by the mouse inoculation method. By the PCR method, rickettsia DNAs could be detected in 12 of 13 rodents from which the rickettsiae were isolated, and in 10 of 42 rodents from which no rickettsiae were isolated. These findings indicate that the PCR method is a simple and specific procedure to detect R. tsutsugamushi in wild rodents. On the other hand, the results of the PCR method demonstrated that the middle area of Okayama Prefecture was highly (44-81%) contaminated with R. tsutsugamushi.

Animals↗
PubMed1998

Energy expenditure and efficiency of energy use in rodents: desert and non-desert species.

Feeding and the search for food are the predominant activities of most rodents. Since desert rodents inhabit regions of generally low food availability, it has been theorized that their energetic requirements would be lower and/or their efficiency to use energy for maintenance and growth would be higher than for rodents from more temperate regions. Indeed, the basal metabolic rate, average daily metabolic rate and field metabolic rate of desert rodents have been found to be lower than those of non-desert rodents. However, the ability to use energy intake for maintenance by desert rodents was calculated to be lower than that of non-desert rodents. In addition, granivores were not different from omnivores and herbivores in energy use efficiency, but herbivores were more efficient than omnivores.

Animals↗
PubMed2002

Flea, rodent, and plague ecology at Chuchupate Campground, Ventura County, California.

Chuchupate Campground in Ventura County, California, was closed to the public for 18 years (1982 to 2000) because of uncontrolled vector fleas and persistent plague antibody titers in rodents. The primary purpose of this study was to clarify the plague ecology of Chuchupate Campground by identifying involved rodents and their vector fleas and by determining many of their ecological parameters: abundance, flea and host preferences and diversities, and flea seasonality. Rodents and fleas were identified to species, some fleas were tested for Yersinia pestis, and rodent bloods were analyzed for the presence of antibodies to Y. pestis. During this study, 20 flea species were identified from 10 rodent and one lagomorph species collected. Five species of rodents were seropositive for plague during 13 of the 17 years in which plague testing was conducted. A likely reservoir species was not determined, but evidence of plague resistance was discovered in Merriam's chipmunks (Tamias merriami) and dusky-footed woodrats (Neotoma fuscipes). The "susceptible" rodent and flea complexes at Chuchupate are the California ground squirrel (Spermophilus beecheyi) and its fleas, Oropsylla montana and Hoplopsyllus anomalus, Merriam's chipmunk and its flea, Eumolpianusfornacis, and the dusky-footed woodrat and its flea, Orchopeas sexdentatus. Host preference, diversity, and seasonality of fleas are discussed, as well as the pivotal role of woodrat houses and nests as foci for hosts, fleas, and plague.

Animals↗
PubMed2003

[Small rodents in the forest ecosystem as infectious disease reservoirs].

Due to numerousness of populations and width of ecologic valence, small rodents are important parts of almost any forest ecosystem. The represent an important animal group, which connects primary makers with higher trophic levels. They transmit various infectious diseases dangerous for the health of people and domestic and wild animals (trichinosis, leptospirosis, tick encephalitis, Lyme disease, hemorrhagic fever with renal syndrome, etc.). The following species of small rodents live in forest ecosystems of Croatia: Chletrionomys glareolus Schreib., Arvicola terrestris L, M. subterraneus de Sel., M. arvalis Pall., M. agrestis L, M. multiplex Fat., Apodemus agrarius Pall., A. sylvaticus L. and A. flavicollis Melch. Small rodents transmit causative agents of diseases in active (excretion products) of passive (ectoparasites and endoparasites) ways. Their multiplication potential is quite high. Transmission of certain disease sometimes takes place extremely fast due to the high number of rodents, their high movability and distribution, and the fact that they easily get in touch with men and domestic and wild animals. The number of population of each species is directly influenced by abiotic and biotic factors and changes during one year and in a several year period. In a year when the influence of ecologic factors is favorable, it is presumed that the number of these rodents will significantly increase, by which the danger of their damaging effect also increases. The following factors influence the increase of a small rodent population: number and physiologic condition of the population, meteorologic conditions, habitat, food sources, natural enemies, and diseases. The occurrence of an epidemic is closely connected to the number and infectivity of causative agents. Regular control of the number of rodent population and their infectivity can help in planning preventive epidemiologic and sanitary measures to preclude the occurrence of epidemics and individual cases of disease among animals and humans who come in contact with forest (forest workers, holiday makers, hikers, soldiers, tourists, etc.).

Animals↗
PubMed2006

[Investigation on rodents' natural infection of Orientia tsutsugamushi in some areas of Inner Mongolia and Xinjiang, China].

OBJECTIVE: To investigate rodents' natural infection of Orientia tsutsugamushi (Ot) in some areas of Inner Mongolia and Xinjiang, China. METHODS: DNAs were extracted from spleens of the captured mice and nested-polymerase chain reaction (nPCR) technique was used to detect the Ot-Sta56 gene. Six positive samples were sequenced and analyzed by Clustal X (5.0) and DNA Club software. RESULTS: A total of 90 rodents were captured in Inner Mongolia, and the overall prevalence of Ot was 6.67%. There was no significant difference in infection rates among the positive rodents species. 20 rodents were captured in Xinjiang, and the prevalence of Ot was 5.00%. The geographical difference in infection rates was not statistically significant between Inner Mongolia and Xinjiang. 9 rodents were captured in farmlands of Inner Mongolia and Xinjiang but there was no positive samples found. 101 rodents were captured in grasslands, and the prevalence of Ot was 6.93%. The Sta56 gene nucleotide sequence homology to Karp strain of N59 (from Microtus maximowiczii), N69 (from Cricetulus barabensis) and X33(from Cricetus cricetus) was 99%. The sequence homology to Taitung-2 strain and TW461 strain of N65 (from C. barabensis) was 94%, and the sequence homology to Taitung-2 strain and TW461 strain of N88(from Apodemus agrarius) was also 94%. The sequence homology to Oishi strain of N90 (from A. agrarius) was 96.00%. CONCLUSION: Our findings indicated that infections of Ot did exist in rodents captured from Inner Mongolia and Xinjiang. The genotypes of Ot in Inner Mongolia and Xinjiang were quite complex, with some of them belonged to Karp type, and the others belonged to Taitung-2, TW461 and Oishi types which providing evidence for further investigation on the scrub typhus fuci in the two areas.

Animals↗
PubMed2006

[Investigation on Borrelia burgdorferi sensu lato in ticks and rodents collected in Da Xing-An Mountains Forest areas of China].

OBJECTIVE: To detect and study the types of Borrelia burgdorferi sensu lato in ticks and rodents from Da Xing-An Mountains Forest areas of China. METHODS: Nested PCR was performed to amplify 5S-23S rRNA intergenic spacer of B. burgdorferi. Positive products were analysed by restriction fragment length polymorphism (RFLP) and single strand conformation polymorphism (SSCP), specimens showing unique RFLP profile were sequenced and analysed. RESULTS: 1336 Ixodes persulcatus, 144 Dermacento silvarum, 144 Haemaphysalis concinna and 145 rodents of 9 species were collected from 16 sections of Da Xing-An Mountains Forest areas of China. Specific fragments were amplified from 293 I. persulcatus and 6 D. silvarum and 5 rodents of 4 species. B. burgdorferi was not detected in H. concinna. Among the positively tested I. persulcatus, 209 contained B. garinii genospecies and 45 contained B.afzelii genospecies based on RFLP. Moreover, B.garinii genospecies consisted of B. garinii 20047 and B. garinii NT29. 17 adult I. persulcatus were simultaneously infected with B. garinii 20047 and B. garinii NT29. Nine adult I. persulcatus were simultaneously infected with B. garinii 20047 and B. afzelii. Four adult I. persulcatus were simultaneously infected with B. garinii 20047 and B. garinii NT29 and B. afzelii. Two D. silvarum were infected with B. garinii 20047, 1 D. silvarum with B. garinii 20047, 2 D. silvarum with B. afzelii. 3 rodents were infected with B. garinii 20047 while 2 rodents were infected with B. garinii NT29. Mixed infection was not found in D. silvarum and rodents. In addition, nine I. persulcatus and one D. silvarum specimens showed unique RFLP pattern. Data from sequential analysis showed that they all belonged to B. garinii. PCR-SSCP profiles of 5S-23S rRNA intergenic spacer of B. burgdorferi in the positive specimens exceeded 36 types; B. garinii 20047 showed 16 types while B. garinii NT29 showing 11 types, B. afzelii showing 9 types. SSCP profiles of the specimens coinfected with multiple B. burgdorferi was relatively complex. CONCLUSION: The infection of B. burgdorferi was found in the ticks and rodents in Da Xing-An Mountains Forests areas. The infection rate of I. persulcatus was high. B. garinii was predominant genospecies, and the population of B. burgdorferi was heterogeneous in the area. Mixed infections of different B. burgdorferi genospecies in ticks were found. I. persulcatus and Clethrionomys rufocanus were possibly served as major vector and major host for B. burgdorferi, respectively, suggesting that further study is needed to confirm the coinfection in humans and animals in this region.

Animals↗
PubMed1995

Interaction between acari ectoparasites and rodents in Suez Governorate, Egypt.

From the medical point of view, the relation between man and rodents comes in the priority. Some rodent populations are wild but others are commensal and live in close association with man. They steal his food and conveying many zoonotic diseases. Their arthropod ectoparasites play an important role in conveying or transmitting these zoonotic diseases. Several disorders and diseases of man are tick borne relapsing fever, Rocky mountain spotted fever, Lyme disease, and many others. Besides numerous species of mites occasionally infest man. They transmit several diseases as Rickettsia tsutsugamushi fever, epidemic haemorrhagic fever, and they cause severe allergic reaction. The results obtained are summarized in the following (1) Six species and subspecies of rodents were detected. In a descending order of abundance, they were (a) Rattus norvegicus, (b) Rattus rattus alexandrinus (c) Rattus rattus frugivorous (d) Acomys cahirinus (e) Gerbillus gerbillus asyutensis (f) Mus m. praetextus. (2) The most common rodent was R. norvegicus and the least common was M. musculus. (3) The collected ticks and mites were 2 genera of tick larvae; Rhipicephalus species and Hyalomma species. The collected mites were Ornithonyssus bacoti and Laelaps nuttali. (4) Most of the tick larvae were collected from wild rodents; Gerbillus g. asyutensis. (5) Most of the mites were collected from commensal rodents particularly R. norvegicus. Descriptive morphology and illustrations were given to the collected rodents and their acari ectoparasites.

Animals↗
PubMed1996

Flea ectoparasites of commensal rodents in Shebin El Kom, Menoufia Governorate, Egypt.

Rodents population are widely distributed in some Egyptian Governorates, particularly those in the Nile Delta. Generally speaking, rodents particularly those living in close association with man, play a major role in human health, welfare and economy. Besides, their arthropod ectoparasites are important vectors of pathogenic agents as well as they themselves are causative agents of many allergic disorders. No doubt, the increase in rodent population is followed by an increase in many zoonotic diseases. In Shebin El Kom city, the capital of Menoufia Governorate three commensal rodents were identified. They were Mus musculus (house mouse), Rattus rattus (black rat) and Rattus norvegicus (Norway rat). The maximal rat index was in Autumn (0.69) and minimal was in Winter (0.2). Five species of fleas were collected from the rodents. They were Xenopsylla cheopis (57.7%), Xenopsylla ramesis. (12.7%), Pulex irritans (12.7%), Leptopsylla segnis (11.3%) and Ctenocephalides felis (5.6%). The maximal flea index was in Spring (1.02) and the minimal was in Winter (zero) The highly infested rodent species was R. rattus (0.65/rat), R. norvegicus (0.62/rat) and the lowest was M. musculus (0.45/mouse). The overall flea index was 0.59. The role of fleas in disease transmission was included. No doubt, to carry out feasible control measures against rodents and their ectoparasites complete understanding of their bionomics must be well studied.

Animals↗