OBJECTIVETo investigate the impact of impoundment and active public health interventions on rodent populations and rodent-borne diseases in the Three Gorges reservoir region from 1997 to 2012.

METHODSSurveillance data from 1997 to 2012 were extracted from the Public Health Surveillance System of The Three Gorges established in 1997. Temporal changes in the incidences of hemorrhagic fever with renal syndrome (HFRS) and leptospirosis, rodent density, pathogen-carrying rates, and their correlations were analyzed.

RESULTSThe average indoor and outdoor rodent densities decreased overall from 1997 to 2012. The average densities decreased by 47.72% (from 4.38% to 2.29%) and 39.68% (from 4.41% to 2.66%), respectively, after impoundment (2003-2012) compared with before impoundment (1997-2002). The average annual incidence rates of HFRS and leptospirosis were 0.29/100,000 and 0.52/100,000, respectively, and decreased by 85.74% (from 0.68/100,000 to 0.10/100,000) and 95.73% (from 1.47/100,000 to 0.065/100,000), respectively, after impoundment compared with before impoundment. Incidences of HFRS and leptospirosis appear to be positively correlated with rodent density in the reservoir area.

CONCLUSIONThis study demonstrated that rodent density and incidences of rodent-borne diseases decreased and were maintained at low levels during construction of the Three Gorges dam. Measures that reduce rodent population densities could be effective in controlling rodent-borne diseases during large-scale hydraulic engineering construction.

Animal Distribution ; Animals ; China ; epidemiology ; Disease Reservoirs ; Hantavirus Infections ; epidemiology ; veterinary ; Leptospirosis ; epidemiology ; virology ; Population Density ; Rodent Diseases ; epidemiology ; microbiology ; virology ; Rodentia ; Seasons ; Time Factors ; Water Supply ; Zoonoses

The present study was performed to know the infection status of intestinal helminths in a most common species of field mice, Apodemus agrarius, from 2 southern regions of Korea. Total 133 and 103 mice were collected by the mouse trap in Hapcheon-gun, Gyeongsangnam-do and Gurye-gun, Jeollanam-do, respectively, from July 2005 to June 2006. The small intestine of each mouse was resected and longitudinally opened with a pair of scissors. The intestinal contents were washed with 0.85% saline until the supernatant became clear. Helminths were collected with naked eyes or under a stereomicroscope from the sediment of the intestinal content. More than 11 species of helminths (4 nematode spp., 5 trematode spp., and 2 cestode spp.) were recovered. Among these, heligmosomoid nematodes (97.5%) was the most highly and heavily infected species. As the members of trematodes, Plagiorchis muris, Brachylaima sp., Echinostoma hortense, Echinostoma cinetorchis, and unidentified echinostome larvae were found in the small intestines of 35 (14.8%), 12 (5.1%), 6 (2.5%), 1 (0.4%), and 1 (0.4%) mice respectively. Two species of tapeworms, Hymenolepis nana and Hymenolepis diminuta were also detected in 79 (33.5%) and 21 (8.9%) mice, respectively. Conclusively, heligmosomoid nematodes were the most prevalent (dominant) species among more than 11 helminth species detected, and Brachylaima sp. fluke is newly added in the list of intestinal trematodes in Korea.
Animals ; Helminthiasis/epidemiology/parasitology ; Helminths/*classification/*isolation & purification ; Intestinal Diseases, Parasitic/epidemiology/parasitology/*veterinary ; Korea/epidemiology ; Murinae/*parasitology ; Prevalence ; Rodent Diseases/*epidemiology/parasitology

Toxoplasma 3 main clonal lineages are designated as type I, II, and III; however, atypical and mixed genotypes were also reported. This study was conducted for detection of Toxoplasma gondii genotypes in rats (Rattus rattus) in Riyadh region, Saudi Arabia. PCR test on T. gondii B1 gene was conducted on ELISA IgM positive samples for confirmation of the infection. However, genetic analysis of the SAG2 locus was performed to determine T. gondii genotypes using PCR-RFLP technique. PCR test on T. gondii B1gene showed that 22 (81.5%) out of the 27 ELISA IgM positive samples have T. gondii DNA. Genotypic analysis shows that, of the total 22 PCR positive samples, only 13 (59.1%) were of type II, 7 (31.8%) were of type III, and 2 (9.1%) were of an unknown genotype. It is obvious that the prevalence of both type II and III is high in rats. No reports have been available on T. gondii genotypes among rats in Riyadh region, and only little is known about its seroprevalence in rats. Future studies on T. gondii genotypes in rats using multi-locus markers is needed in Riyadh region, Saudi Arabia for better understanding of T. gondii pathogenesis and treatment in humans and animals.
Animals ; Genotype ; *Genotyping Techniques ; Molecular Epidemiology ; Polymerase Chain Reaction ; Polymorphism, Restriction Fragment Length ; Prevalence ; Rats ; Rodent Diseases/epidemiology/*parasitology ; Saudi Arabia/epidemiology ; Toxoplasma/*classification/*genetics/isolation & purification ; Toxoplasmosis, Animal/epidemiology/*parasitology

Surveys on helminthic fauna of the nutria, Myocastor coypus, have seldom been performed in the Republic of Korea. In the present study, we describe Strongyloides myopotami (Secernentea: Strongyloididae) recovered from the small intestine of feral nutrias. Total 10 adult nutrias were captured in a wetland area in Gimhae-si (City), Gyeongsangnam-do (Province) in April 2013. They were transported to our laboratory, euthanized with ether, and necropsied. About 1,300 nematode specimens were recovered from 10 nutrias, and some of them were morphologically observed by light and scanning electron microscopies. They were 3.7-4.7 (4.0+/-0.36) mm in length, 0.03-0.04 (0.033) mm in width. The worm dimension and other morphological characters, including prominent lips of the vulva, blunted conical tail, straight type of the ovary, and 8-chambered stoma, were all consistent with S. myopotami. This nematode fauna is reported for the first time in Korea.
Animals ; Republic of Korea/epidemiology ; Rodent Diseases/epidemiology/*parasitology ; Rodentia ; Strongyloides/*isolation & purification ; Strongyloidiasis/epidemiology/parasitology/*veterinary

This study reports the first case of Capillaria hepatica infection in a nutria in Korea. Ten nutrias, captured near the Nakdong River, were submitted to our laboratory for necropsy. White-yellowish nodules were found in the liver of 1 of the nutrias at necropsy. Histologically, the lesions were granulomatous, and infiltrations of lipid-laden macrophages, eosinophils, and several multinucleated giant cells were observed. The lesions consisted of numerous eggs and necrotic hepatocytes. The eggs were lemon-shaped and had polar plugs at the ends of both long sides. The eggs were morphologically identified as those of C. hepatica. Worldwide, C. hepatica infection in nutrias is very rare. Nutrias are a kind of livestock, as well as wildlife; therefore, an epidemiological study for parasitic infections needs to be conducted.
Animals ; Capillaria/*isolation & purification ; Enoplida Infections/epidemiology/parasitology/*veterinary ; Female ; Male ; Republic of Korea/epidemiology ; Rodent Diseases/*parasitology ; Rodentia

To gain more insights into epidemiologic characteristics and genotype of hantavirus in Apodemus agrarius in Changbai Area. Complete hantavirus S segment sequences were amplified by RT-PCR and sequenced. The phylogenetic trees were constructed for analysis of genetic characters of hantavirus. A total of 58 Apodemus agrarius were trapped in the epidemic areas, and complete hantavirus S segment sequences were obtained from 4 lung samples of these rodents (6. 90%0). Phylogenetic analysis of the four S segment sequences indicated that all viruses isolated from Apodemu sagrarius were closely related to genotype 6 of Hantaan virus (95. 8%-96. 3%, nucleotide identity; 98. 6%-99. 5%, amino acid identity), all of them had a specific S387 different from other genotypes of Hantaan virus.
Animals ; Base Sequence ; China ; epidemiology ; DNA, Complementary ; chemistry ; genetics ; Disease Reservoirs ; virology ; Genotype ; Hantavirus ; classification ; genetics ; isolation & purification ; Hantavirus Infections ; epidemiology ; veterinary ; virology ; Lung ; virology ; Murinae ; virology ; Phylogeny ; RNA, Viral ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Rodent Diseases ; virology ; Sequence Analysis, DNA ; Viral Proteins ; genetics

Animals ; Capillaria ; isolation & purification ; China ; epidemiology ; Communicable Diseases, Emerging ; epidemiology ; parasitology ; veterinary ; Enoplida Infections ; epidemiology ; parasitology ; veterinary ; Humans ; Liver Diseases, Parasitic ; epidemiology ; parasitology ; veterinary ; Neglected Diseases ; epidemiology ; parasitology ; veterinary ; Parasite Egg Count ; veterinary ; Prevalence ; Rats ; Risk Assessment ; Rodent Diseases ; epidemiology ; parasitology ; Zoonoses ; epidemiology ; parasitology

To determine geographical patterns of natural parasite infections among wild rodents, a total of 46 wild rodents from 3 different localities in northern Gangwon-do (Province), Korea were examined for intestinal parasite infections. Along with nematodes such as hookworms and Syphacia spp., Plagiorchis muris (2 specimens) (Trematoda) were collected from striped field mice, Apodemus agrarius. In a Korean wood mouse, Apodemus peninsulae, the overall nematode infections were similar to A. agrarius, but an adult worm of Echinostoma hortense (Trematoda) was collected. In addition, 2 species of cestodes, i.e., Hymenolepis nana and Hymenolepis diminuta, were collected from A. agrarius. Through this survey, A. agrarius and A. peninsule were confirmed as the natural definite hosts for zoonotic intestinal helminths, i.e., P. muris, E. hortense, H. nana, and H. diminuta, in northern Gangwon-do, Korea. Considering increased leisure activities around these areas, seasonal and further comprehensive surveys on wild rodents seem to be needed to prevent zoonotic parasite infections.
Animals ; Cestoda/isolation & purification ; Cestode Infections/epidemiology/parasitology/*veterinary ; Geography ; Humans ; Intestinal Diseases, Parasitic/epidemiology/parasitology/*veterinary ; Murinae ; Nematoda/isolation & purification ; Nematode Infections/epidemiology/parasitology/*veterinary ; Parasitic Diseases, Animal/epidemiology/*parasitology ; Republic of Korea/epidemiology ; Rodent Diseases/epidemiology/*parasitology ; Trematoda/isolation & purification ; Trematode Infections/epidemiology/parasitology/*veterinary ; Zoonoses

Monthly surveys were conducted to investigate the occurrence of chigger mites and seroprevalence of scrub typhus among small mammals in Jeollanam-do, the southwestern part of Korea, from November 2006 through October 2007. Fifty-eight small mammals, including 57 Apodemus agrarius (98.3%) and 1 Crocidura lasiura (1.7%), were captured, and a total of 4,675 chigger mites representing 4 genera and 8 species were collected from them. The chigger infestation rate among small mammals was 69.0%. The most predominant species in A. agrarius was Leptotrombidium scutellare (54.0%), followed by Leptotrombidium pallidum (39.4%), Leptotrombidium orientale (4.4%), Leptotrombidium palpale (1.1%), Neotrombicula tamiyai (0.6%), Eushoengastia koreaensis (0.3%), Neotrombicula gardellai (0.3%), and Cheladonta ikaoensis (<0.1%). The chigger index of A. agrarius was the highest in October (740.0), followed by November (242.0), September (134.6), March (98.3), February (38.2), January (35.3), December (34.5), April (30.8), and May (1.7). The average antibody positive rate of scrub typhus in wild rodents was 50.0%. The seropositive rates were high in October (100.0%) and November (83.3%), whereas those in other months were relatively low (28.6-57.1%). The chigger index of L. scutellare rapidly increased in September to form an acuminate peak in October, followed by a gradual decline. These results suggest that the outbreak of scrub typhus in the southwestern part of Korean peninsula is mostly due to L. scutellare.
Animals ; Antibodies, Bacterial/blood ; Antibody Specificity ; Arachnid Vectors/*microbiology ; *Disease Reservoirs ; Humans ; Murinae/parasitology ; Orientia tsutsugamushi/*immunology ; Population Dynamics ; Public Health Surveillance ; Republic of Korea/epidemiology ; Rodent Diseases/parasitology/transmission ; Scrub Typhus/epidemiology/*transmission ; Seasons ; Seroepidemiologic Studies ; Shrews/parasitology ; Species Specificity ; Trombiculiasis/parasitology/veterinary ; Trombiculidae/*microbiology

OBJECTIVEIn order to investigate Hantavirus (HV) infection of captured rodents and to understand the genotypes and the molecular characteristic of Hantaviruses in Shenzhen.

METHODSThe captured rodents were classified and the density of distribution was calculated. A total of 472 animals were captured, among which Rattus norvegicus was the dominant group. The total viral RNA was extracted from the lung tissues positive with HV antigens by immunofluorescent assay and gene sequence of M fragment was amplified with RT-nested-PCR by using the Hantavirus genotype specific primers. The amplified genes were then sequenced, and subjected to genotyping and homology analysis.

RESULTSThe results of genotype analysis showed that the Hantaviruses taken from twenty-one lung specimens in Rattus norvegicus in Shenzhen city belonged to the Hantavirus type II (SEOV). Results in homology analysis suggested that the homology among twenty-one samples should be rather high with 95.4% of nucleotide sequence identity and they belonged to the same subtype. Phylogenetic tree analysis showed that they were branched into at least six different lineages, and were highly homologized with SZ2083. We also found that these virus strains had not shown more highly homology of nucleotide sequence in nearest district, whereas revealed consistency in farther district.

CONCLUSIONThe major hosts of Hantaviruses in Shenzhen city were Rattus norvegicus and the epidemic strains were genotyped as SEO-type. Nucleotide sequence and deduced amino acid sequence from different rodents were highly homologous, while nucleotide mutation had also been observed. Further studies are required to explore the possible viruses' sequence mutation.

Animals ; China ; epidemiology ; DNA Primers ; DNA, Viral ; Genotype ; Hantavirus ; classification ; genetics ; Hantavirus Infections ; epidemiology ; veterinary ; virology ; Polymerase Chain Reaction ; RNA, Viral ; Rats ; Rodent Diseases ; epidemiology ; virology ; Sequence Homology