Abstract
The principal objective of this study was to investigate the prevalence of toxoplasmosis in household and stray cats in Seoul, Republic of Korea. We collected blood samples from 72 stray and 80 household cats, and all samples were examined by ELISA and nested PCR. The overall positive rates of Toxoplasma gondii in stray cats were 38.9% (28/72), with 15.3% (11/72) in ELISA and 30.6% (22/72) in PCR. The positive rate in male stray cats was slightly higher than that of female stray cats. The highest positive rate of T. gondii infection was noted in Gangnam and Songpa populations in ELISA and in Gwangjin population in PCR. In household cats, however, we could not detect any specific antibodies or DNA for T. gondii. In conclusion, we recognized that the infection rate of toxoplasmosis in stray cats in Seoul was considerably high but household cats were free from infection.
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Key words: Toxoplasma gondii, cat, ELISA, PCR
Toxoplasma gondii is a worldwide endemic parasite, and a member of the phylum Apicomplexa, subclass coccidian. It can infect most warm-blooded animals and humans, and can occasionally cause permanent neurological damage, with or without hydrocephalus, or chorioretinitis. Infections with this zoonotic agent are acquired principally by eating food or water contaminated with oocysts or tissue cysts of
T. gondii. Cats have an important role in the spread of toxoplasmosis, because they are the only animal that excretes resistant oocysts into the environment. A single cat may shed more than 100 million oocysts into the environment [
1,
2]. Internationally, the presence of large populations of feral cats have become a controversial issue, due to their impact on cat overpopulation, animal welfare, public health, and the environment, and also due to disagreements about the best methods for their control [
3]. Also in Korea, large numbers of stray cats are found roaming residential streets and have become a target of public grievances. They disrupt people's sleep, make noise, and cause traffic accidents, and this has been a fairly serious issue since 2000. In addition, they threaten the population as a source of zoonotic diseases, including toxoplasmosis. Chai et al. [
4] successfully isolated and maintained the
T. gondii parasite from a Korean ocular patient, which was designated the Korean Isolate-1 (KI-1).
Seroprevalence of
T. gondii infection in stray and household cats were reported in Spain [
5], Tehran [
6], China [
7], and Japan [
8]. Whereas in Korea, several epidemiological surveys of
T. gondii in just stray cats have been conducted in recent years [
9-
11], and no researchers have, until now, conducted a comparison of prevalence of
T. gondii infections in household and stray cats in the same area. It should be noted that the precise disposition of the household cat population remains obscure. Therefore, the present study was first conducted to investigate the prevalence of
T. gondii infection in stray and household cats in Seoul, Korea, via ELISA and nested PCR analyses.
A total of 80 household cats and 72 stray cats were subjected in this study. Blood samples of household cats were collected whenever they were admitted to a veterinary clinic by their owners for regular health check-ups. On the other hand, blood samples of stray cats were received from other veterinary clinics, located in the same areas where the household cats' samples were obtained, through the local government's TNR (Trap, Neuter, Return) program, the purpose of which was to reduce the numbers and control the natural reproduction rates of urban stray cats. A total 9 areas, Jungrang, Nowon, Dongdaemun, Gangnam, Gwangjin, Seongbuk, Dobong, Songpa, and Gangbuk, in Seoul were surveyed (
Fig. 1). All samples were collected from April to September 2008. Blood samples were collected from cephalic or jugular punctures of each cat, permitted to clot at room temperature and centrifuged for 5 min at 1,800
g. Serum and whole blood were collected after centrifuging and transferred to the Division of Malaria and Parasitic Diseases at the Korea Centers for Disease Control and Prevention.
General methods of DNA extraction were carried out by the manufacturer's instructions using the DNeasy Mini column kit (Qiagen, Hilden, Germany). The DNA concentration of each blood sample was measured with a Quant-iT™, dsDNA HS Assay Kit (Invitrogen, Carlsbad, California, USA) and read by Qubit™, Fluorometer (Invitrogen), and the average DNA concentration was 15 ng and the range was a minimum 7 ng to a maximum 46 ng. All samples were stored at -20℃ until used. ELISA for toxoplasmosis was performed essentially in accordance with the procedure of Choi et al. [
12] and a nested PCR targeting the specific B1 gene for
T. gondii was followed according to the condition with Kim et al. [
9]. The PCR products were purified using the QIAquick PCR purification kit (Qiagen, Valencia, California, USA) and sequenced by a commercial laboratory (Macrogen, Seoul, Korea).
Our study involved 72 stray cats (32 males and 40 females) and 80 household cats (40 males and 40 females, spay 4, and aged 4 months to 7 years) and they had no specific symptoms in external appearance. As the seroprevalence of
T. gondii in cats varied depending on their living type (stray or domestic), age, the diagnostic method used, and geographic area [
13], the prevalence of
T. gondii in stray cats has been reported to be variable from 5% to 45% in recent years in Korea [
9-
11].
The results of this study were similar to the previous reports. The overall positive population of
T. gondii in stray cats was 38.9% (28/72); the rate was 15.3% (11/72) by ELISA and 30.6% (22/72) by nested PCR (
Table 1). The positive rate of
T. gondii in nested PCR analysis was 2 times higher than that of ELISA and the positive samples only in ELISA showed absorbance of 0.4-0.9 (over the 0.25 cut-off value), while the range of positives in both ELISA and nested PCR was wider, from 0.1-0.9 (
Fig. 2). This was similar to the reports by Kim et al. [
9] and the development of a highly sensitive and specific PCR will help in the early diagnosis of toxoplamsosis in blood [
14,
15]. In terms of sex, the male positive rate was 18.8% (6/32) and the female rate was 12.5% (5/40) in stray cats by ELISA, and 28.1% (9/32) in males and 32.5% (13/40) in females by nested PCR (
Table 2). The positive rate of
T. gondii in male cats was slightly higher than that in females. Similar [
5] or opposing [
6,
7,
9] results have been reported. Regionally, the prevalence of
T. gondii varied and the highest positive rates of
T. gondii infection were noted in Gangnam and Songpa for ELISA, and Gwangjin for nested PCR (
Table 2). However, it was not possible to directly compare the prevalences of
T. gondii infection in different areas because of a difference in the sample numbers and environmental characteristics of each region.
Our study of household cats was relatively important, because the prevalence of
T. gondii in household cats in Korea has never been assessed until now. According to reports in other nations, the prevalence of
T. gondii in household cats was 25.5% in Spain [
5], 36% in Tehran [
6], 17.9% in China [
7], and 5.4% in Japan [
8]. In most reports, the prevalence of stray cats was higher than that of household cats in the same area. However, interestingly, we could not detect any specific antibodies and DNA of
T. gondii in household cats. By this interesting result, the authors could assume that most household cats are managed quite well by their owner's. Stray cats in Seoul are important wild animals because they occupy the highest position in the urban food-chain and their numbers gradually increased [
10]. These cats establish territory in the same fashion as wild animals and generally kept out of other cats' way in each area. Therefore, it is assumed that the life cycle of
T. gondii is maintained in the territory of each cat and in each area. Concurrently, a potential zoonotic threat to humans and animals remains a concern in all of them [
9].
In conclusion, toxoplasmosis is widespread among stray cats of Seoul, whereas household cats are not infected. Further epidemiologic surveys of toxoplasmosis in stray cats from various areas in Seoul and studies of the life styles of household cats will be need in order to gain a more complete understanding of T. gondii infection.
ACKNOWLEDGEMENTS
This work was supported by a grant (NIH-4847-302-210-13, 2009) from the National Institute of Health, Korea Centers for Disease Control and Prevention.
References
- 1. Frenkel JK. In Ambroise-Thomas P, Peterse E eds, Biology of Toxoplasma gondii. Congenital toxoplasmosis: scientific background, clinical management and control. 2000, Paris, France. Springer-Verlag; pp 9-25.
- 2. Omata Y, Oikawa H, Kanda M, Mikazuki K, Nakabayashi T, Suzuki N. Experimental feline toxoplasmosis: humoral immune responses of cats inoculated orally with Toxoplasma gondii cysts and oocysts. J Vet Med Sci 1990;52:865-867.
- 3. Wallace JL, Levy JK. Population characteristics of feral cats admitted to seven trap-neuter-return programs in the United States. J Feline Med Surg 2006;8:279-284.
- 4. Chai JY, Lin A, Shin EH, Oh MD, Han ET, Nam HW, Lee SH. Laboratory passage and characterization of an isolate of Toxoplasma gondii from an ocular patient in Korea. Korean J Parasitol 2003;41:147-154.
- 5. Miro G, Montoya A, Jimenez S, Frisuelos C, Mateo M, Fuentes I. Prevalence of antibodies to Toxoplasma gondii and intestinal parasites in stray, farm and household cats in Spain. Vet Parasitol 2004;126:249-255.
- 6. Haddadzadeh HR, Khazraiinia P, Aslani M, Rezaeian M, Jamshidi S, Taheri M, Bahonar A. Seroprevalence of Toxoplasma gondii infection in stray and household cats in Tehran. Vet Parasitol 2006;138:211-216.
- 7. Zhang H, Zhou DH, Zhou P, Lun ZR, Chen XG, Lin RQ, Yuan ZG, Zhu XQ. Seroprevalence of Toxoplasma gondii infection in stray and household cats in Guangzhou, China. Zoonoses Public Health 2009;56:502-505.
- 8. Maruyama S, Kabeya H, Nakao R, Tanaka S, Sakai T, Xuan X, Katsube Y, Mikami T. Seroprevalence of Bartonella henselae, Toxoplasma gondii, FIV and FeLV infections in domestic cats in Japan. Microbiol Immunol 2003;47:147-153.
- 9. Kim HY, Kim YA, Kang SW, Lee HS, Rhie HG, Ahn HJ, Nam HW, Lee SE. Prevalence of Toxoplasma gondii in stray cats of Gyeonggi-do, Korea. Korean J Parasitol 2008;46:199-201.
- 10. Lee JY, Lee SE, Lee EG, Song KH. Nested PCR-based detection of Toxoplasma gondii in German shepherd dogs and stray cats in South Korea. Res Vet Sci 2008;85:125-127.
- 11. Sohn WM, Nam HW. Western blot analysis of stray cat sera against Toxoplasma gondii and the diagnostic availability of monoclonal antibodies in sandwich-ELISA. Korean J Parasitol 1999;37:249-256.
- 12. Choi WY, Nam HW, Youn JH, Kim DJ, Kong Y, Kang SY, Cho SY. Detection of antibodies in serum and cerebrospinal fluid to Toxoplasma gondii by indirect latex agglutination test and enzyme-linked immunosorbent assay. Korean J Parasitol 1992;30:83-90.
- 13. Dubey JP, Saville WJ, Stanek JF, Reed SM. Prevalence of Toxoplasma gondii antibodies in domestic cats from rural Ohio. J Parasitol 2002;88:802-803.
- 14. Jones CD, Okhravi N, Adamson P, Tasker S, Lightman S. Comparison of PCR detection methods for B1, P30, and 18S rDNA genes of T. gondii in aqueous humor. Invest Ophthalmol Vis Sci 2000;41:634-644.
- 15. Paugam A, Dupouy-Camet J, Sumuyen MH, Romand S, Lamoril J, Derouin F. Detection of Toxoplasma gondii parasitemia by polymerase chain reaction in perorally infected mice. Parasite 1995;2:181-184.
Fig. 1Areas surveyed (rectangles) for Toxoplasma gondii infection in stray and household cats in Seoul, Korea.
Fig. 2ELISA evaluation for nested PCR positive and negative samples.
Table 1.Comparison of ELISA and PCR analysis for detecting Toxoplasma gondii infection in stray cats
Table 1.
|
|
ELISA
|
Total |
|
|
Positive |
Negative |
|
PCR |
Positive |
5 |
17 |
22 |
|
Negative |
6 |
44 |
50 |
|
Total |
11 |
61 |
72 |
Table 2.Result of Toxoplasma gondii infection with ELISA and PCR analysis in stray and household cats in each area of Seoul
Table 2.
|
|
Jungrang
|
Nowon
|
Dongdaemun
|
Gangnam
|
Gwangjin
|
Sungbuk
|
Dobong
|
Songpa
|
Gangbuk
|
Total
|
|
|
M |
F |
M |
F |
M |
F |
M |
F |
M |
F |
M |
F |
M |
F |
M |
F |
M |
F |
M |
F |
|
Stray cats |
Number |
1 |
3 |
3 |
2 |
10 |
7 |
3 |
3 |
11 |
21 |
- |
- |
- |
- |
3 |
3 |
1 |
1 |
32 |
40 |
|
ELISA |
- |
1 |
- |
1 |
2 |
2 |
2 |
- |
1 |
- |
- |
- |
- |
- |
1 |
1 |
- |
- |
6 |
5 |
|
PCR |
- |
- |
- |
1 |
2 |
1 |
1 |
1 |
5 |
10 |
- |
- |
- |
- |
1 |
- |
- |
- |
9 |
13 |
|
Household cats |
Number |
9 |
11 |
8 |
4 |
5 |
2 |
8 |
7 |
1 |
4 |
2 |
4 |
2 |
2 |
2 |
1 |
3 |
1 |
40 |
40 |
Citations
Citations to this article as recorded by
- Detection of IgG Antibodies Against T. gondii and Associated Risk Factors in Domestic and stray Cats in Lusaka, Zambia.
Farai Phiri
University of Zambia Journal of Agricultural and Biomedical Sciences.2024;[Epub] CrossRef - The detection and phylogenetic characterization of Cryptosporidium, Cystoisospora, and Giardia duodenalis of cats in South Korea
Chi Sun Yun, Bo-Youn Moon, Kichan Lee, Su Min Kang, Bok-Kyung Ku, Mi-Hye Hwang
Frontiers in Cellular and Infection Microbiology.2023;[Epub] CrossRef - Prevalence and Molecular Characterization of Toxoplasma gondii and Toxocara cati Among Stray and Household Cats and Cat Owners in Tehran, Iran
Poorya Karimi, Soheila Shafaghi-Sisi, Ahmad Reza Meamar, Gelareh Nasiri, Elham Razmjou
Frontiers in Veterinary Science.2022;[Epub] CrossRef - Prevalence of toxoplasmosis in semi-domesticated and pet cats within and around Bangkok, Thailand
Tawin Inpankaew, Panpicha Sattasathuchana, Chanya Kengradomkij, Naris Thengchaisri
BMC Veterinary Research.2021;[Epub] CrossRef - Detection and genotypes of Toxoplasma gondii DNA in feces of domestic cats in Colombia
Alejandro Zamora-Vélez, Jessica Triviño, Sebastián Cuadrado-Ríos, Fabiana Lora-Suarez, Jorge Enrique Gómez-Marín
Parasite.2020; 27: 25. CrossRef - All about toxoplasmosis in cats: the last decade
J.P. Dubey, C.K. Cerqueira-Cézar, F.H.A. Murata, O.C.H. Kwok, Y.R. Yang, C. Su
Veterinary Parasitology.2020; 283: 109145. CrossRef - Seroprevalence and B1 gene Phylogeny of Toxoplasma gondii of Dogs and Cats in Republic of Korea
Yeojin Park, Jinhyeong Noh, Hyun-Ji Seo, Keun-Ho Kim, Subin Min, Mi-Sun Yoo, Bo-Ram Yun, Jong-Ho Kim, Eun-Jin Choi, Doo-Sung Cheon, Sung-Jong Hong, Soon-Seek Yoon, Yun Sang Cho
The Korean Journal of Parasitology.2020; 58(3): 257. CrossRef - Genetic Analysis of Zoonotic Gastrointestinal Protozoa and Microsporidia in Shelter Cats in South Korea
Dongmi Kwak, Min-Goo Seo
Pathogens.2020; 9(11): 894. CrossRef - Endemicity of Toxoplasma infection and its associated risk factors in Cebu, Philippines
Rochelle Haidee D. Ybañez, Chadinne Girlani R. Busmeon, Alexa Renee G. Viernes, Jorim Z. Langbid, Johanne P. Nuevarez, Adrian P. Ybañez, Yoshifumi Nishikawa, Adriana Calderaro
PLOS ONE.2019; 14(6): e0217989. CrossRef - Status of common parasitic diseases in Korea in 2019
Sun Huh
Journal of the Korean Medical Association.2019; 62(8): 437. CrossRef - Excretion of Toxoplasma gondii oocysts from Feral Cats in Korea
Kyu-Sung Ahn, Ah-Jin Ahn, Sang-ik Park, Woon-Mok Sohn, Jae-han Shim, Sung-Shik Shin
The Korean Journal of Parasitology.2019; 57(6): 665. CrossRef - Increasing Prevalence of the Sensitization to Cat/Dog Allergens in Korea
Bok Won Park, Jun Yeong Park, Eun Byul Cho, Eun Joo Park, Kwang Ho Kim, Kwang Joong Kim
Annals of Dermatology.2018; 30(6): 662. CrossRef - Prevalence of Toxoplasma gondii infection in household and feral cats in Korea
Sung-Eon Kim, Ran Choi, Seung-Won Kang, Changbaig Hyun
Journal of Parasitic Diseases.2017; 41(3): 823. CrossRef - Seroprevalence and risk factors associated with Toxoplasma gondii infection in domestic rabbits and humans
Rasha M.M. Abou Elez, Eman A.A. Hassanen, Hala M.N. Tolba, Ibrahim Elsohaby
Veterinary Parasitology: Regional Studies and Reports.2017; 8: 133. CrossRef - T-Cell Mediated Immune Responses in Obstetric Population Acutely Infected With Toxoplasmosis in Kano, Nigeria
Ibrahim, A., Kumurya, A. S., Yahaya, H., Abdu, A., Ado, B. K., Ella, E. E., Suleiman, A. B., Sulaiman, M. A., Aminu, M. A., Koki, A. Y.
UMYU Journal of Microbiology Research (UJMR).2017; 2(1): 217. CrossRef - Evaluation of biochemical and haematological parameters and prevalence of selected pathogens in feral cats from urban and rural habitats in South Korea
Jusun Hwang, Nicole Gottdenker, Mi-Sook Min, Hang Lee, Myung-Sun Chun
Journal of Feline Medicine and Surgery.2016; 18(6): 443. CrossRef - <i>Toxoplasma gondii</i> B1 Gene Detection in Feces of Stray Cats around Seoul, Korea and Genotype Analysis of Two Laboratory-Passaged Isolates
Bong-Kwang Jung, Sang-Eun Lee, Hyemi Lim, Jaeeun Cho, Deok-Gyu Kim, Hyemi Song, Min-Jae Kim, Eun-Hee Shin, Jong-Yil Chai
The Korean Journal of Parasitology.2015; 53(3): 259. CrossRef - Toxoplasma gondii seroprevalence in pet cats in Norway and risk factors for seropositivity
Bente Kristin Sævik, Randi Ingebjørg Krontveit, Kristine P Eggen, Nina Malmberg, Stein I Thoresen, Kristin W Prestrud
Journal of Feline Medicine and Surgery.2015; 17(12): 1049. CrossRef - Molecular detection of Toxoplasma gondii DNA in milk and risk factors analysis of seroprevalence in pregnant women at Sharkia, Egypt
Heba A. Ahmed, Saleh M. Shafik, Mahmoud E. M. Ali, Sanya T. Elghamry, Alshymaa A. Ahmed
Veterinary World.2014; 7(8): 594. CrossRef - Seroprevalence of Toxoplasma gondii and Bartonella henselase infection in stray cats of the Daejeon City, Korea
Hyung-Jin Park, Sang-Eun Lee, Sung-Hee Hong, Won-Ja Lee, Kyoung-Won Seo, Kun-Ho Song
Korean Journal of Veterinary Research.2014; 54(2): 87. CrossRef - Prevalence of Toxoplasma gondii Infection in Household Cats in Korea and Risk Factors
Sung-Hee Hong, Young-Il Jeong, Jae-Young Kim, Shin-Hyeong Cho, Won-Ja Lee, Sang-Eun Lee
The Korean Journal of Parasitology.2013; 51(3): 357. CrossRef - Seroprevalence of Toxoplasma gondiiand associated risk factors among pregnant women in Jimma town, Southwestern Ethiopia
Endalew Zemene, Delenasaw Yewhalaw, Solomon Abera, Tariku Belay, Abdi Samuel, Ahmed Zeynudin
BMC Infectious Diseases.2012;[Epub] CrossRef - Serologic Survey of Toxoplasmosis in Seoul and Jeju-do, and a Brief Review of Its Seroprevalence in Korea
Hyemi Lim, Sang-Eun Lee, Bong-Kwang Jung, Min-Ki Kim, Mi Youn Lee, Ho-Woo Nam, Jong-Gyun Shin, Cheong-Ha Yun, Han-Ik Cho, Eun-Hee Shin, Jong-Yil Chai
The Korean Journal of Parasitology.2012; 50(4): 287. CrossRef - A Surge in the Seroprevalence of Toxoplasmosis among the Residents of Islands in Gangwha-gun, Incheon, Korea
Zhaoshou Yang, Pyo Yun Cho, Seong Kyu Ahn, Hye-Jin Ahn, Tong-Soo Kim, Chom-Kyu Chong, Sung-Jong Hong, Seok Ho Cha, Ho-Woo Nam
The Korean Journal of Parasitology.2012; 50(3): 191. CrossRef - Seroprevalence of Toxoplasma gondii and Neospora caninum in dogs from Korea
Thuy Nguyen, Se-Eun Choe, Jae-Won Byun, Hong-Bum Koh, Hee-Soo Lee, Seung-Won Kang
Acta Parasitologica.2012;[Epub] CrossRef - Clinical Features of Ocular Toxoplasmosis in Korean Patients
Young-Hoon Park, Jae-Hyung Han, Ho-Woo Nam
The Korean Journal of Parasitology.2011; 49(2): 167. CrossRef - Development and Clinical Evaluation of a Rapid Serodiagnostic Test for Toxoplasmosis of Cats Using Recombinant SAG1 Antigen
Chom-Kyu Chong, Wooseog Jeong, Hak-Yong Kim, Dong-Jun An, Hye-Young Jeoung, Jeong-Eun Ryu, A-Ra Ko, Yong-Joo Kim, Sung-Jong Hong, Zhaoshou Yang, Ho-Woo Nam
The Korean Journal of Parasitology.2011; 49(3): 207. CrossRef - Seroprevalence of Toxoplasma gondii infection in household and stray cats in Lanzhou, northwest China
Song-Ming Wu, Xing-Quan Zhu, Dong-Hui Zhou, Bao-Quan Fu, Jia Chen, Jian-Fa Yang, Hui-Qun Song, Ya-Biao Weng, De-He Ye
Parasites & Vectors.2011;[Epub] CrossRef
