Seroepidemiological Survey of Zoonotic Diseases in Small Mammals with PCR Detection of Orientia tsutsugamushi in Chiggers, Gwangju, Korea

Serosurveillance for zoonotic diseases in small mammals and detection of chiggers, the vector of Orientia tsutsugamushi, were conducted from September 2014 to August 2015 in Gwangju Metropolitan Area. Apodemus agrarius was the most commonly collected small mammals (158; 91.8%), followed by Myodes regulus (8; 4.6%), and Crocidura lasiura (6; 3.5%). The highest seroprevalence of small mammals for O. tsutsugamushi (41; 26.3%) was followed by hantaviruses (24; 15.4%), Rickettsia spp. (22; 14.1%), and Leptospira (2; 1.3%). A total of 3,194 chiggers were collected from small mammals, and 1,236 of 3,194 chiggers were identified with 7 species of 3 genera: Leptotrombidium scutellare was the most commonly collected species (585; 47.3%), followed by L. orientale (422; 34.1%), Euchoengastia koreaensis (99; 8.0%), L. palpale (58; 4.7%), L. pallidum (36; 2.9%), Neotrombicula gardellai (28; 2.3%), and L. zetum (8; 0.6%). L. scutellare was the predominant species. Three of 1,236 chigger mites were positive for O. tsutsugamushi by PCR. As a result of phylogenetic analysis, the O. tsutsugamushi strain of chigger mites had sequence homology of 90.1-98.2% with Boryong. This study provides baseline data on the distribution of zoonotic diseases and potential vectors for the development of prevention strategies of vector borne diseases in Gwangju metropolitan area.

Prevalence of Mycoplasma pneumoniae Antibodies in Healthy Residents of Jeonnam Province / 대한임상미생물학회지

BACKGROUND: Mycoplasma pneumoniae is the most frequent cause of respiratory tract infections in schoolaged children and adolescents. For appropriate use of antibiotics, diagnosis of M. pneumoniae infection in routine clinical practice has been based on serology using a single serum sample. We evaluated the seroprevalence of anti-M. pneumoniae-specific antibodies in 500 asymptomatic, healthy persons in Jeonnam Province. METHODS: Sera were collected from 500 healthy persons in Jeonnam Province. Anti-M. pneumoniae antibody titer was measured using a microparticle agglutination assay Serodia Myco II (Fujirebio, Japan) and VIRCELL IgM Mycoplasma ELISA kits (Vircell, Granada, Spain). RESULTS: Anti-M. pneumoniae antibody titers in 500 healthy individuals were 1:20 in 344 (68.8%), 1:40 in 16 (3.2%), 1:80 in 71 (14.2%), 1:160 in 45 (9.0%), 1:320 in 14 (2.8%), and 1:160) and positive IgM, and an assessment of current infection with single serum serology has its limitation for the diagnosis of M. pneumoniae infections.

Two species of goby, Boleophthalmus pectinirostris and Scartelaos sp., as the new second intermediate hosts of heterophyid fluke in Korea

A survey was performed in order to determine the infection status of the metacercariae of heterophyid fluke in two goby species, Boleophthalmus pectinirostris and Scartelaos sp., collected from Gangjin-gun, and Shinangun, Sooncheon-shi, Jeollanam-do, Republic of Korea. A total of three metacercariae of Heterophyopsis continua was found in only one B. pectinirostris (10.0%) from Gangjin-gun. Heterophyes nocens metacercariae were detected in 24 B. pectinirostris (96.0%) and 14 Scartelaos sp. (63.6%) from Shinan-gun. Heterophyopsis continua metacercariae were found in 11 B. pectinirostris (44.0%) and 21 Scartelaos sp. (95.5%) from Shinan-gun. Stictodora fuscata metacercariae were detected in 18 B. pectinirostris (72.0%) from Shinan-gun. No metacercariae were detected in 20 B. pectinirostris from Sooncheon-shi. From the above results, this study is the first to prove that B. pectinirostris and Scartelaos sp. serve as the second intermediate hosts of some heterophyid flukes in Korea.

Prevalence of Leptospira interrogans in Wild Rodents in Korea

Leptospirosis has been known as endemic disease in Korea since 1984. Wild rodent, mostly Apodemus agrarius, has been known as an important source of leptospiral infection especially in rainy circumstances in harvest reason of rural area. The infection rates of Leptospira interrogans in field rodents, Apodemus agrarius, was investigated by culture and PCR detection of leptospiral DNA, and compared with previous data. Furthermore, the serogroup and serovar were investigated. Two hundred twenty two Apodemus agrarius were captured during October to December 1996. Spirohaetes were isolated from 22 (9.9%) and leptospiral DNA was detected in an additional six rodents (12.6%). Subsequent cross-agglutinin absorption test, monoclonal antibody reactivity classified 21 cultures among 22 isolates as Leptospira interrogans serogroup Icterohemorrhagiae serovar lai. The above data did not differ from previous survey in 1984 to 1987. There was no significant change of Leptospira interrogans infection in field rodents in Korea.

Genetic Heterogeneity in 56 kDa gene of Orientia tsutsugamushi Genotype Karp

The type-specific PCR and the sequence analysis of 56 kDa gene of Orientia tsutsugamushi infected in field rodents specimens have shown intratypic genetic heterogeneity in genotype Karp. In sequence comparison, this genetic heterogeneity was mainly due to insertion or deletion of a repeated unit in variable domain I (VDI) region. These results suggested that genetic duplication or deletion of the specific sequence rnight be involved in intratypic genetic heterogeneity of Orientia tsutsugamushi.

Infection Rate and Serotype Distribution of Orientia tsutsugamushi arnong Field Rodents in Chollanamdo using Nested Polymerase Chain Reaction

The 86 strains of field rodents captured in Chollanamdo were analyzed its infection rates of Orientia tsutsugamushi by nested PCR. The detection rate of O. tsutsugamushi was 14.3 % in A. agrarius whereas O. tsutsugamushi could not be detected in C. lasiura. In locality, the rodents captured in the mountainous area showed higher detection rate than suburban area. In the case of detection rate by organs, the spleen was most appropriate specimen, but in two cases, O. tsutsugamushi could be detected in only kidney specimens. The major serotype of detected O. tsutsugamushi was serotype Karp, but four cases were serotype Boryong. These serotypes were confirmed by nucleotide sequence determination of amplified PCR products. In conclusion, the serotype Karp was the major O. tsutsugamushi in Chollanamdo.