Hostname: page-component-cd9895bd7-hc48f Total loading time: 0 Render date: 2024-12-27T09:04:42.082Z Has data issue: false hasContentIssue false

Echinococcosis on the Tibetan Plateau: prevalence and risk factors for cystic and alveolar echinococcosis in Tibetan populations in Qinghai Province, China

Published online by Cambridge University Press:  04 March 2004

P. M. SCHANTZ
Affiliation:
Division of Parasitic Diseases, National Center For Infectious Diseases, Centers For Disease Control and Prevention, Atlanta, GA 30341, USA
H. WANG
Affiliation:
Qinghai University Medical School, Xining, Qinghai Province, China
J. QIU
Affiliation:
Sichuan Center For Disease Control, Chengdu, China
F. J. LIU
Affiliation:
National Hydatid Disease Control Center, Urumqi, Xinjiang Province, China
E. SAITO
Affiliation:
Division of Parasitic Diseases, National Center For Infectious Diseases, Centers For Disease Control and Prevention, Atlanta, GA 30341, USA
A. EMSHOFF
Affiliation:
Division of Parasitic Diseases, National Center For Infectious Diseases, Centers For Disease Control and Prevention, Atlanta, GA 30341, USA
A. ITO
Affiliation:
Department of Parasitology, Asahikawa Medical College, Asahikawa, Japan
J. M. ROBERTS
Affiliation:
Division of Parasitic Diseases, National Center For Infectious Diseases, Centers For Disease Control and Prevention, Atlanta, GA 30341, USA
C. DELKER
Affiliation:
Boulder-Lhasa Sister City Project, Boulder, CO, USA

Abstract

Infections by larval stages of tapeworms of the genus Echinococcus (echinococcosis or hydatid disease) are zoonotic infections of major public health importance throughout much of the world. Humans become infected through accidental ingestion of eggs passed in faeces of canid definitive hosts. Tibetan populations of China have some of the highest documented levels of infections by both Echinococcus granulosus and E. multilocularis, the causes of cystic and alveolar echinococcosis, respectively. In this study we measured the prevalence of cystic (CE) and alveolar (AE) echinococcosis disease in Tibetan communities in Qinghai, Province, China, and identified putative risk factors for both infections in these communities. 3703 volunteers in three predominately Tibetan counties of Qinghai were surveyed between June 1997 and June 1998. Parasitic lesions were diagnosed by imaging of characteristic space-occupying lesions in abdominal organs (ultrasound) or the lungs (radiographs). Specific serodiagnostic assays (Dot-ELISA and Em2-ELISA) were performed on sera of positively imaged subjects to further distinguish the disease agent. All participants completed a questionnaire documenting age, sex, education level, occupation, lifestyle (nomadic or settled), slaughter practices, drinking water source, hygienic practice and association with dogs. Data were analyzed using SAS version 8. 6·6% of the volunteers had image-confirmed infection with E. granulosus (CE) and 0·8% had E. multilocularis (AE) infection. The significant univariate factors for echinococcal infection (both CE and AE) included livestock ownership, Tibetan ethnicity, female gender, low income, herding occupation, limited education, water source, age greater than 25 years old, poor hygienic practices, offal disposal practices and dog care. Multivariate analysis revealed that livestock ownership was a significant risk factor for both forms of the disease, as well as age greater than 25 years, female gender, herding occupation, and being nomadic (vs semi-nomadic or settled). No additional significant risk factors were identified among the 344 nomadic participants. Being female and being older than 25 years of age were significant factors among the 1906 semi-nomadic participants. Among the 1445 settled participants, allowing dogs to sleep indoors was statistically significant. Issues such as inadequate assessment of animal ownership, selection bias, disease misclassification, and loss of information may have led to reduction in strength of some risk factor associations and need to be addressed in future epidemiologic analysis of echinococcosis in this population.

Type
Research Article
Copyright
© 2003 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

CHI, P., ZHANG, W., ZHANG, Z., HASYET, M., LIU, F., DING, Z., ANDERSON, F. L., TOLLEY, H. D. & SCHANTZ, P. M. ( 1990). Cystic echinococcosis in the Xinjiang Uyger Autonomous Region, People's Republic of China. I. Demographic and epidemiologic data. Tropical Medicine and Parasitolgy 41, 157162.Google Scholar
CRAIG, P. S., DESHAN, L., MACPHERSON, C. N., DAZHONG, S., REYNOLDS, D., BARNISH, G., GOTTSTEIN, B. & ZHIRONG, W. ( 1992). A large focus of alveolar echinococcosis in central China. Lancet 340 (8823), 826831.CrossRefGoogle Scholar
CRAIG, P. S., GIRAUDOUX, P., SHI, D., BARTHOLOMOT, B., BARNISH, G., DELATTRE, P., QUERE, J. P., HARRAGA, S., BAO, G., WANG, Y., LU, F., ITO, A. & VUITTON, D. A. ( 2000). An epidemiological and ecological study of human alveolar echinococcosis transmission in south Gansu, China. Acta Tropica 77, 167177.CrossRefGoogle Scholar
ECKERT, J., SCHANTZ, P. M., GASSER, R. B., TORGERSON, P. R., BESSONOV, A. S., MOVSESSIAN, S. O., THAKUR, A., GRIMM, F. & NIKOGOSSIAN, M. A. ( 2001). Geographic distribution and prevalence. In WHO/OIE Manual on Echinococcosis in Humans and Animals: A Public Health Problem of Global Concern ( ed. Eckert, J., Gemmel, M. A., Meslin, F.-X. & Pawlowski, Z. S. ), pp. 100141. World Organisation for Animal Health, Paris, France.
ITO, A., MA, L., SCHANTZ, P. M., GOTTSTEIN, B., LIU, Y.-H., CHAI, J.-J., ABDEL HAFEZ, S., ALTINTAS, N., JOSHI, D. D., LIGHTOWLERS, M. W. & PAWLOWSKI, Z. S. ( 2000). Differential serodiagnosis for cystic and alveolar echinococcosis and E. multilocularis protoscolex (EM18). American Journal of Tropical Medicine and Hygiene 60, 188192.Google Scholar
ITO, A., URBANI, C., QIU, J., VUITTON, D. A., QIU, D., HEATH, D. D., CRAIG, P. S., ZHENG, F. & SCHANTZ, P. M. ( 2003). Control of echinococcosis and cysticercosis: a public health challenge to international cooperation in China. Acta Tropica 86, 317.CrossRefGoogle Scholar
LIU, F. J., QIU, J. M. & SCHANTZ, P. M. ( 1999). Epidemiology of echinococcosis in a Tibetan community in Western Sichuan. In Proceedings Workshop on Echinococcosis Control Strategy in China. Urumqi, Institute for Endemic Disease Research and Control. (In Chinese.)
MACPHERSON, C. N. L. & MILNER, R. ( 2003). Performance characteristics and quality control of community based ultrasound surveys for cystic and alveolar echinococcosis. Acta Tropica 85, 203209.CrossRefGoogle Scholar
PAWLOWSKI, Z. S., ECKERT, J., VUITTON, D. A., AMMANN, R. W., KERN, P., CRAIG, P. S., DAR, K. F., DE ROSA, F., FILICE, C., GOTTSTEIN, B., GRIMM, F., MACPHERSON, C. N. L., SATO, N., TODOROV, T., UCHINO, J., VON SINNER, W. & WEN, H. ( 2001). Echinococcosis in humans: clinical aspects, diagnosis and treatment. In WHO/OIE Manual on Echinococcosis in Humans and Animals: A Public Health Problem of Global Concern ( ed. Eckert, J., Gemmel, M. A., Meslin, F.-X. & Pawlowski, Z. S.), pp. 2071. Wld. Org. Anim. Hlth., Paris, France.
QIU, J. M., LIU, F. J. & SCHANTZ, P. M. ( 1998). Epidemiology and transmisssion of alveolar echinococcosis in East Tibetan Plateau. In Proceedings First National Hydatidology Conference of Imaging and Therapeutics and International Symposium on Transmission and Control of Echinococcus Infection, pp. 104108. Urumqi, Xinjiang Medical University. (In Chinese.)
SCHANTZ, P. M. ( 1994). Larval cestodiases. In Infectious Diseases. Fifth Edn. (ed. Hoeprich, P., Jordan, C. & Wilson, R.), pp. 850860. Philadelphia: J.B. Lippincott.
SCHANTZ, P. M., CHAI, J., CRAIG, P. S., ECKERT, J., JENKINS, D. J., MACPHERSON, C. N. L. & THAKUR, A. ( 1995). Epidemiology and control of hydatid disease. In Echinococcus and Hydatid Disease (ed. Thompson, R. C. A. & Lymbery, A. J. ), pp. 233331. CAB International, UK.
WANG, H., LIU, F., SCHANTZ, P. M., ITO, A., DELKER, C., CAO, D., MA, S. & ZHAO, H. ( 1999). A survey of hydatid disease in Tibetan populations in Qinghai Province: prevalence, distribution and risk factors for cystic and alveolar echinocococcosis. Archivos Internacionales Hidatidosis XXXIII, 316.Google Scholar
WANG, Q., QIU, J. M., SCHANTZ, P. M., HE, J. G., ITO, A. & LIU, F. ( 2001). Investigation of risk factors for development of human hydatidiosis among households raising livestock in Tibetan areas of Western Sichuan Province. Chinese Journal of Parasitology and Parasitic Diseases 19, 289293.Google Scholar
WEN, H. & YANG, W.-G. ( 1997). Public health importance of cystic echinococcosis in China. Acta Tropica 67, 133145.CrossRefGoogle Scholar
YAO, P. L., HUANG, N. Q., FU, L. M. & FANG, H. ( 1965). Hepatic alveolar hydatid disease. China Surgery Journal 13 (5), 400401.Google Scholar