Echinococcosis in Tibetan populations, Western Sichuan Province, China.We screened 3,199 people from Shiqu County, Sichuan Province, China, for abdominal echinococcosis Echinococcosis Definition
Echinococcosis (Hydatid disease) refers to human infection by the immature (larval) form of tapeworm, Echinococcus. One of three forms of the Echinococcus spp., E. (hydatid disease hydatid disease: see tapeworm. ) by portable ultrasound combined with specific serodiagnostic tests. Both cystic echinococcosis (CE) (Echinococcus granulosus Echinococcus granulosus, also called the Hydatid worm, is a cyclophyllid cestode that parasitizes the small intestine of canids as an adult, but which has important intermediate hosts such as livestock and humans, where it causes hydatid disease. infection) and alveolar alveolar /al·ve·o·lar/ (al-ve´o-lar) [L. alveolaris ] pertaining to an alveolus.
Relating to an alveolus. echinococcosis (AE) (E. multilocularis) were co-endemic in this area at the highest village prevalence values recorded anywhere in the world: 12.9% were infected with one or the other form (6.8% CE and 6.2% AE). Prevalences of both CE and AE were significantly higher in female than male patients and increased with the age of the person screened. Pastoral herdsmen were at highest risk for infection (prevalence 19.0%). Prevalence of CE varied in 5 townships from 0% to 12.1%, whereas AE prevalence ranged from 0% to 14.3%. Risk factors associated with both infections included the number of owned dogs, frequency of contact with dogs, and sources of drinking water drinking water
supply of water available to animals for drinking supplied via nipples, in troughs, dams, ponds and larger natural water sources; an insufficient supply leads to dehydration; it can be the source of infection, e.g. leptospirosis, salmonellosis, or of poisoning, e.g. .
Human cystic echinococcosis (CE), caused by infection with the larval stage larval stage - Describes a period of monomaniacal concentration on coding apparently passed through by all fledgling hackers. Common symptoms include the perpetration of more than one 36-hour hacking run in a given week; neglect of all other activities including usual basics like of Echinococcus granulosus, and alveolar echinococcosis (AE), caused by infection with the larval stage of E. multilocularis, are 2 of the most pathogenic zoonotic Zoonotic
A disease which can be spread from animals to humans.
Mentioned in: Zoonosis parasitic helminthic hel·min·thic
1. Of or relating to worms, especially parasitic worms.
2. Tending to expel worms.
See anthelmintic. infections of humans in the Northern Hemisphere (1). Human CE occurs worldwide in association with herding, within which the main dog-sheep cycle for E. granulosus is transmitted (l). Human AE is a much rarer parasitic infection; transmission occurs in several regions of the Northern Hemisphere, including the United States United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and the fourth largest country in area. , Europe, Central Asia, Siberia, Japan, and China (2). In China, echinococcosis occurs mainly in western regions and provinces, including Xinjiang Uygur Xin·jiang Uy·gur also Sin·kiang Ui·ghur or Sin·kiang Ui·gur
An autonomous region of extreme western China. It came under Chinese control in the 16th century and was the site of a conflict between China and the Soviet Union in 1969. Autonomous Region, Qinghai Province, Gansu Province, Ningxia Hui Autonomous Region Ningxia Hui Autonomous Region (nĭng`shyä` hwē), autonomous region (1994 est. pop. 5,030,000), c.25,600 sq mi (66,321 sq km), N China. The capital is Yinchuan. , and Sichuan Province (3). A previous pilot survey showed that human echinococcosis was prevalent in western Sichuan Province, situated on the eastern Tibetan Plateau The Tibetan Plateau, also known as the Qinghai-Tibetan (Qingzang) Plateau is a vast, elevated plateau in East Asia covering most of the Tibet Autonomous Region and Qinghai Province in the People's Republic of China and Ladakh in Kashmir. , and that both human CE and AE were present. The average prevalence was 4.0%; CE accounted for 2.1% and AE 1.9% (4).
Shiqu County (longitude 97[degrees]20'00"-99[degrees]15'28" E and latitude 32[degrees]19"28"-34[degrees]20'40"N) is located in the northwest corner of Ganzi Prefecture in Sichuan Province (average altitude 4,200 m). The county covers 25,141 [km.sup.2], located on the eastern part of the Tibetan Plateau. Grassland covers 83.5% of this treeless area, where the weather is cold (annual average temperature -1.6[degrees]C). Ethnic Tibetans comprise 98% of the total population; they are primarily involved with livestock production and herding. The total number of livestock is >630,000. In addition, a large number of dogs, including owned dogs and strays, exist in the area (5). We conducted a village-based community epidemiologic study epidemiologic study A study that compares 2 groups of people who are alike except for one factor, such as exposure to a chemical or the presence of a health effect; the investigators try to determine if any factor is associated with the health effect of human echinococcosis from 2000 to 2002 in Shiqu County, Ganzi Tibetan Autonomous Region, Sichuan Province, to further understand the epidemiology of human AE in this region.
Materials and Methods
The screening program was undertaken from 2000 to 2002; 26 villages in 5 townships in Shiqu County, were included (Figure 1). A total of 3,199 volunteers were self-selected after the purpose of the study was explained to the communities by local village leaders; volunteers were assured free diagnosis and chemotherapeutic treatment for echinococcosis, if indicated. Study participants ranged in age from 1 to 86 years (median 32 years). Fifty-two percent (1,660) were female patients, and 48% (1,539) were male patients. Persons of Tibetan ethnicity comprised 95% of the sampled population. The other participants listed their ethnicity as Han (4.5%), Hui (0.2%), or other (0.3%). Almost half of the participants (52.9%) raised livestock, including yaks, sheep, or goats, as the primary source of their income. Other listed occupations included student (19.1%), public servant (9.8%), preschooler pre·school·er
1. A child who is not old enough to attend kindergarten.
2. A child who is enrolled in a preschool.
Noun 1. (3.2%), illiterate child (2.0%), semifarmer (2.5%), farmer (1.1%), employee (2.2%), or other (7.3%).
[FIGURE 1 OMITTED]
For each registered participant, a questionnaire designed to obtain information on demographics and animal ownership was completed. Questions mainly concerned occupation, education level, dog ownership and number, frequency of dog contact, fox hunting, drinking water source, and hygienic hy·gien·ic
1. Of or relating to hygiene.
2. Tending to promote or preserve health.
3. Sanitary. practices.
Screening and Diagnostic Criteria for Echinococcosis
All participants were examined by abdominal ultrasound Abdominal Ultrasound Definition
Ultrasound technology allows doctors to "see" inside a patient without resorting to surgery. A transmitter sends high frequency sound waves into the body, where they bounce off the different tissues and ; those with space-occupying lesions space-occupying lesions
substantial physical lesions, e.g. neoplasm, hemorrhage, granuloma, which occupy space; the effect is more significant if the lesion is within a space confined by bone, e.g. thorax, cranium, bone marrow cavity. in the liver were asked to give venous blood venous blood
n. Abbr. v
Blood that has passed through the capillaries of various tissues other than the lungs, is found in the veins, in the right chambers of the heart, and in pulmonary arteries, and is usually dark red as a result of a samples to detect Echinococcus Echinococcus /Echi·no·coc·cus/ (e-ki?no-kok´us) a genus of small tapeworms, including E. granulo´sus, usually parasitic in dogs and wolves, whose larvae (hydatids) may develop in mammals, forming hydatid tumors or cysts chiefly in antibody by using enzyme-linked immunosorbent assay enzyme-linked immunosorbent assay
Enzyme-linked immunosorbent assay (ELISA)
A diagnostic blood test used to screen patients for AIDS or other viruses. (ELISA ELISA (e-li´sah) Enzyme-Linked Immuno-Sorbent Assay; any enzyme immunoassay using an enzyme-labeled immunoreactant and an immunosorbent.
n. ) and immunoblot with E. granulosus hydatid cyst hydatid cyst
A cyst formed as a result of infestation by larvae of the tapeworm Echinococcus granulosus. Also called echinococcus cyst. fluid as antigen (6-8), as well as specific antibodies against E. multilocularis using ELISA and immunoblot with recombinant Em18 antigen (9,10). Diagnosis of human echinococcosis is mainly dependent on pathognomonic pathognomonic /pa·thog·no·mon·ic/ (path?ug-no-mon´ik) specifically distinctive or characteristic of a disease or pathologic condition; denoting a sign or symptom on which a diagnosis can be made. ultrasound images complemented by serum antibody confirmation of suspect CE/AE images (6,11). Investigators used the criteria for classification proposed by the World Health Organization Informal Working Group on Echinococcosis for CE (11), and the PNM PNM Public Service Company of New Mexico
PNM People's National Movement (Trinidad)
PNM Perpustakaan Negara Malaysia (National Library, Malaysia)
PNM Price Negotiation Memorandum system for classification of human AE, in which P stands for hepatic location of the parasite, N refers to extrahepatic ex·tra·he·pat·ic
Originating or occurring outside the liver. 2involvement of neighboring organs, and M stands for absence or presence of distant metastases Metastasis (plural, metastases)
A tumor growth or deposit that has spread via lymph or blood to an area of the body remote from the primary tumor.
Mentioned in: Malignant Melanoma (12). CE Cases were defined as follows: 1) presence of characteristic cyst-like images detected on abdominal ultrasound and a positive ELISA result with hydatid cyst fluid antigen; 2) presence of pathognomonic cyst cyst, abnormal sac in the body, filled with a fluid or semisolid and enclosed in a membrane. Cysts can be congenital but are usually acquired, the most common locations being the skin and the ovaries. images detected on abdominal ultrasound, but negative by ELISA (Figure 2). In addition, CE cases, on the basis of the conformational features of cysts, were differentiated into 6 types (CL, CE1, CE2, CE3, CE4, and CE5 ) and subdifferentiated by size into 3 subtypes (small [s], medium [m], and large [l]) within each type. A case of AE was defined as follows: 1) presence of pathognomonic progressive AE type lesion detected on abdominal ultrasound, regardless of serologic se·rol·o·gy
n. pl. se·rol·o·gies
1. The science that deals with the properties and reactions of serums, especially blood serum.
2. results; 2) presence of calcified Calcified
Hardened by calcium deposits.
Mentioned in: Heart Valve Repair lesions, 1-3 cm in diameter, or nodular nodular
marked with, or resembling, nodules.
see nodular fasciitis (below).
a firm painless nodular swelling, 0. hyperechoic lesions detected on abdominal ultrasound and seropositive seropositive /se·ro·pos·i·tive/ (-poz´i-tiv) showing positive results on serological examination; showing a high level of antibody.
adj. against recombinant Em18; and 3) presence of a calcified lesion (1-3 cm in diameter) detected by abdominal ultrasound and negative for antibodies to the recombinant Em18 antigen but positive by ELISA, with hydatid cyst fluid (Figure 3).
[FIGURES 2-3 OMITTED]
All analyses were performed by using EpiInfo version 5.01a (Centers for Disease Control and Prevention Centers for Disease Control and Prevention (CDC), agency of the U.S. Public Health Service since 1973, with headquarters in Atlanta; it was established in 1946 as the Communicable Disease Center. , Atlanta, GA, USA). Statistical significance was set at p [greater than or equal to] 0.01.
In this study, 84 (2.6%) of 3,199 participants examined by abdominal ultrasound scanning were determined to have an intrahepatic mass with a nonhomogeneous hyperechoic structure that contained scattered calcifications, and with irregular, poorly defined edges. A central necrotic cavity with a hypoechoic pseudoliquid structure and irregular borders was observed in 79 (2.5%) additional persons. In 53 of these participants the infiltrative lesions measured >10 cm in diameter and invaded or surrounded vascular structures, biliary structures, or both. In the other 26 persons, the lesions were nodular, were 3-5 cm in diameter at the longest dimension, and had calcifications. Calcified lesions, 1-3 cm in diameter, were observed in 20 persons. Thus, 163 persons were confirmed by ultrasound scanning to have AE infection, and 46 were suspected of having AE. Confirmatory serodiagnostic tests were performed in Japan and China, respectively. Serodiagnosis serodiagnosis /se·ro·di·ag·no·sis/ (-di?ag-no´sis) diagnosis of disease based on serologic tests.serodiagnos´tic
n. pl. with the EgCF antigen in ELISA was positive in 93 of 94 persons with typical images of AE, 24 of 25 persons with nodular lesions, and 11 of 20 persons with calcified lesions. Additional serologic testing with the Em18 antigen in ELISA and immunoblot was positive in 101 of 102 persons with typical images of AE, 16 of 25 with nodular lesions, and 8 of 14 with calcified lesions (Table 1). Therefore, positive confirmative serology Serology
The division of biological science concerned with antigen-antibody reactions in serum. It properly encompasses any of these reactions, but is often used in a limited sense to denote laboratory diagnostic tests, especially for syphilis. in 35 study participants with a suspect AE image of a nodular lesion or calcified lesion indicated infection with AE. Another patient with a suspect AE image of a nodular lesion in the liver refused to give venous blood, so confirmative serologic tests could not be performed on him, and this case was not counted in the AE category. Thus, of 46 study participants with a suspect AE image, 35 were finally diagnosed as having AE. A total of 198 (6.2%) of 3,199 persons studied were determined to be infected with AE on the basis of abdominal ultrasound images and confirmatory serologic results; 15 (38.5%) of 39 infected persons had inactive, or abortive abortive /abor·tive/ (ah-bor´tiv)
1. incompletely developed.
2. abortifacient (1).
3. cutting short the course of a disease.
1. AE lesions. Ninety-five single AE lesions were located in the fight hepatic lobe Noun 1. hepatic lobe - any of the five lobes forming the liver
liver - large and complicated reddish-brown glandular organ located in the upper right portion of the abdominal cavity; secretes bile and functions in metabolism of protein and carbohydrate and fat; , and 31 were in the left hepatic lobe. Involvement of both fight and left hepatic lobes by a single lesion was observed in 17 patients. In 55 cases, [less than or equal to] 2 distinct foci were observed.
In addition, an ultrasound image of CE in the liver was detected in 216 (6.8%) of 3,199 study participants examined. In 10 cases, ultrasound images showed unilocular unilocular /uni·loc·u·lar/ (-lok´u-ler) having but one cavity or compartment.
Having a single compartment or cavity; monolocular. , cystic lesions with uniform anechoic anechoic /an·echo·ic/ (an-e-ko´ik)
1. without echoes; said of a chamber for measuring the effects of sound.
in ultrasonography, an absence of internal echoes. content, without visible cyst wall, all <5 cm; they were considered to be type CLs. Images characterized by unilocular, simple cyst with uniform anechoic content and visible cyst wall, some exhibiting a snowflake image (7 images <5 cm, 42 images ranging from 5 to 10 cm, and 26 images >10 cm) were observed in 75 patients; they were determined to be Type CE1 (7 CE1s, 42 CE1m, 26 CE1l); In 54 patients, images exhibited multivesicular or multiseptate cysts with a wheel-like appearance; others displayed unilocular cysts with daughter cysts with a honeycomb honeycomb
a mosaic of closely packed units with depressed centers giving a honeycomb appearance.
reticulum. appearance. Eight of these images were <5 cm, 16 images were 5-10 cm, and 30 images were >10 cm; all of these images belonged to type CE2 (8 CE2s, 16 CE2m, 30 CE2l). In 23 cases, images were characterized by anechoic content with detachment of laminated membrane from the cyst wall, visible as a water-lily design; some had a unilocular cyst containing daughter cysts, but the whole cyst form was less rounded. Five of these cysts were <5 cm, 13 cysts were 5-10 cm, and 5 cysts were >10 cm; all were confirmed to be type CE3 (5 CE3s, 13 CE3m, 5 CE3l). In 48 cases, cysts had hyperechoic degenerative contents without daughter cysts. Seventeen of these cysts were <5 cm, 19 were 5-10 cm, and 12 cysts were >10 cm; these images belonged to type CE4 (17 CE4s, 19 CE4m, 12 CE4). Cysts characterized by thick, calcified walls in an arch-shaped form with a cone-shaped shadow, were observed in 6 cases; 3 had images <5 cm, and 3 had cysts 5-10 cm in size; these were determined to be type CE5 (3 CE5s, 3 CE5m). In 18 cases, [greater than or equal to] 1 cystic lesions were identified in the abdominal cavity abdominal cavity
Largest hollow space of the body, between the diaphragm and the top of the pelvic cavity and surrounded by the spine and the abdominal muscles and others. in addition to the liver cysts. In 5 cases, additional cysts were found in the spleen; in 3 cases, additional cysts were found in the pelvic cavity pelvic cavity
The space bounded by the bones of the pelvis and pelvic girdle. ; and in 1 case, a cyst was also found in the kidney. Serologic results in these study participants with CE at ultrasound examination Ultrasound examination
A medical test in which high frequency sound waves are directed at a particular internal area of the body. As the sound waves are reflected by internal structures, a computer uses the data to construct an image of the structures. are shown in Table 1. Serodiagnosis using the EgCF antigen in ELISA was negative in 16 of 161 persons with CE; 12 of 123 persons with CE were seropositive with rEm18 by ELISA and immunoblot (Table 1). No mixed infections were observed.
Distribution by Sex and Age
Of 414 persons with evidence of abdominal echinococcosis, 244 (CE = 134, AE = 110) were female patients, and 170 (CE = 82, AE = 88) were male. Thus, the prevalence of echinococcosis in female patients was 14.7% (244/1,660), and 11.0% (170/1,539) in male patients. Thus, prevalence in female patients was significantly higher than in males ([chi square chi square (kī),
n a nonparametric statistic used with discrete data in the form of frequency count (nominal data) or percentages or proportions that can be reduced to frequencies. ] = 9.46, p<0.01). Compared with other older groups, the population <20 years of age had a lower infection prevalence (5.4%). In general, prevalence increased with age and reached a peak in the age group of >50 to [less than or equal to] 60 (Figure 4). The prevalence in the age group of >10 to [less than or equal to] 20 years was significantly lower than in the age group of >20 to [less than or equal to] 30 years ([chi square] = 10.20, p<0.01). The youngest person infected with CE was 4 years of age, the oldest one was 79 years, and the average age of persons with CE was 39.0 years (n = 216). The youngest persons with AE was 8 years of age, the oldest 80 years, and the average age of AE patients was 43.1 years (n = 198) (Figure 5).
[FIGURES 4-5 OMITTED]
In this study 2,033 persons were screened for echinococcosis from 26 villages in the townships of Yiniu, Mengsha, Arizha, Xiazha, and Qiwu within Shiqu County; 226 infected cases were detected. The overall township prevalence of echinococcosis was 11.1% (range 7.4%-15.1%); 6.2% of patients were diagnosed with AE and 4.9% with CE disease. The highest village prevalences for AE and CE were 14.3% and 12.1%, respectively (Table 2).
Other Risk Factors
Occupation was a major risk factor. Herdsmen had the highest risk for echinococcosis infection, with a total prevalence of 19.0% (322/1,692, p<0.01); the AE prevalence was 9.5% (160/1,692), and the CE prevalence was 9.6% (162/1,692). Part-time herdsmen had a 12.7% prevalence of echinococcosis. Students and preschool children had a lower prevalence (2.8% and 3.0%), while illiterate adolescents were more heavily infected (14.3%) ([chi square] = 21.17, p<0.01) (Table 3).
A total of 2,811 of 3,199 persons examined answered the question about dog ownership. Of these, 496 said they did not own dogs; 2,315 (82.4%) persons had various numbers of dogs (range 1-9). Analysis indicated that the population without owned dogs had a total echinococcosis prevalence of 8.3% (41/496) (CE = 4.4%, AE = 3.8%). In contrast, persons who owned dogs had a total echinococcosis prevalence of 15.6% (360/2,315) (CE = 8.0%, AE = 7.5% [Table 4]).
To a certain extent, education can determine occupation choice and lifestyle. Our results implied that prevalence of echinococcosis had some relationship with the level of education. Among herdsmen, 1,469 (86.8%) of 1,692 were illiterate; the prevalence in this subgroup reached 20.0% (293/1,469), the highest rate in the sampled population. The prevalence in self-identified literate herdsmen was 13.0% (29/223). Among illiterate adolescents, 14.3% were infected. Persons with only primary school education had a 6.0% (53/882) combined infection prevalence, and those with middle school education 9.1% (29/318). Persons with university education had an infection rate of 6.3% (17/268), and preschool children had an echinococcosis infection prevalence of 2.9% (3/105).
Fox hunting was also a risk factor. A total of 2,841 of 3,199 persons examined replied to the question about fox hunting. Results showed that the total prevalence of echinococcosis in populations who said that they neither hunted foxes nor kept fox skin products was 7.6% (29/384) (AE = 3.4%, CE = 4.2%), compared to a prevalence of 15.2% (368/2,427) (CE = 7.8% and AE = 7.4%) for persons who said they kept fox skin products that they had purchased, and 10% (3/30) (CE = 3 and AE = 0) in persons who said they kept fox skin products that they obtained by hunting.
In this mass screening study of Tibetan communities, portable ultrasound examination combined with specific serologic tests was used for the diagnosis of both CE and AE. Survey results indicated that human echinococcosis is a serious public health problem for the inhabitants
The game is based loosely on the concepts from SameGame. of this area, for whom a 12.9% overall prevalence was recorded. In comparison with reports on human echinococcosis in other areas, including other areas of China, the prevalence in northwest Sichuan Province was much higher for both CE and AE (1,3,12,13). The prevalence of CE was higher than in other recognized echinococcosis-endemic areas of the world, including North Africa, South America South America, fourth largest continent (1991 est. pop. 299,150,000), c.6,880,000 sq mi (17,819,000 sq km), the southern of the two continents of the Western Hemisphere. , Russia, and the Middle East (1,12,14,15). Previous ultrasound-based surveys for human AE have shown regional prevalences of <0.05% in continental Europe Continental Europe, also referred to as mainland Europe or simply the Continent, is the continent of Europe, explicitly excluding European islands and, at times, peninsulas. to 4% in Gansu Province in central northwest China (16,17). The most striking observation, however, was that both AE and CE were co-endemic in this area of Sichuan, with a prevalence of 6.8% for CE and 6.2% for AE. Only parts of Turkey, Central Asia, and Siberia have been identified as co-endemic for both human CE and AE (1,14).
In Shiqu County, China, analysis of human CE and AE indicated that prevalence of disease in female patients was significantly higher (14.7%) than in male patients (11.0%). According to according to
1. As stated or indicated by; on the authority of: according to historians.
2. In keeping with: according to instructions.
3. traditional Tibetan custom, women are usually responsible for home chores, including feeding dogs, collecting yak dung for fuel, and milking livestock. Thus, women and girls may have more opportunity to be exposed to Echinococcus-infected dogs and the contaminated contaminated,
v 1. made radioactive by the addition of small quantities of radioactive material.
2. made contaminated by adding infective or radiographic materials.
3. an infective surface or object. environment.
The infection prevalence for both CE and AE for persons in the age groups <20 years was markedly lower than those of other age groups. Prevalence reached a peak among the >50- to 60-year age group. The presence of CE or AE in persons as young as 4 and 8 years, respectively, indicates recent active transmission. In general, CE or AE infection increased with age. However, among persons >60 years of age prevalence of both AE and CE declined, a situation consistent with previous reports (4,15,18); this finding may be associated with early death of persons infected with forms of echinococcosis, particularly with AE. A recent analysis of the relative health impact of echinococcosis in these Tibetan communities showed that CE and AE caused an average of 0.8 disability-adjusted life years Disability-adjusted life years (DALY) is a measure for the overall "burden of disease." Originally developed by the World Health Organization, it is becoming increasingly common in the field of public health and health impact assessment (HIA). lost per person (19), which is an exceptional value.
This analysis showed that AE infection varied from 0% to 14.3% by village and that CE village prevalence ranged from 0% to 12.1%. A trend of gradual decrease in AE in villages from north to south (9.4% vs. 0.9% in the 5 townships surveyed) was observed.
Several factors may contribute to the high prevalence of human AE in this Tibetan population. High densities of small mammals are essential to maintaining the transmission cycle of E. multilocularis, and small mammal populations are also subject to ecologic changes, such as deforestation deforestation
Process of clearing forests. Rates of deforestation are particularly high in the tropics, where the poor quality of the soil has led to the practice of routine clear-cutting to make new soil available for agricultural use. or pasture overgrazing overgrazing
see overstocking. (16,20-22). The involvement of dogs as well as foxes in transmission in eastern Tibet, together with lack of hygiene and probable contamination of the local peridomestic environment, seem to be additional major factors (23,24). For the 5 townships located in the central area of Shiqu County, the geographic conditions, apparent ecologic factors, life style, religion, livestock production, and dog ownership practices appear to be similar; however, human AE village prevalence was markedly variable. We had previously observed that local differences in small mammal abundance over time, possibly associated with overgrazing practices may contribute to variable township AE disease rates (22).
This survey disclosed that 86.8% of herdsmen were illiterate; 20% of them had either CE or AE disease. Consequently, improving the knowledge and awareness of the disease among the traditional nomadic See nomadic computing. population is imperative in any future control or prevention studies. Analysis indicated that both CE and AE risk was related to dog ownership (p<0.01), contact with dogs (p<0.01), source of drinking water, and general hygiene (p<0.01). While the role of domestic and working dogs working dogs
breeds or individuals that are bred for or trained to do specific tasks that help humans in some way, such as guide dogs for the blind, sledge or cart dogs, police or guard dogs, and livestock tending dogs. as the major definitive host for E. granulosus is clear, such is not the case for E. multilocularis. Of particular interest therefore was the strong association between human AE risk and dog ownership or contact. Evidence from community studies in other parts of China (16), the United States (25), and Germany (26) increasingly show that the domestic dog plays a key role in the zoonotic risk for human AE.
Dogs are kept in large numbers by Tibetans and are used primarily to guard property and livestock. In this survey, 82.4% of the population owned dogs, and 21% owned >3 dogs. Buddhist practice forbids killing any animal, including dogs, and this practice leads to large numbers of stray dogs, which mainly gather around temples or townships, where they are fed by monks and herdsmen. Dogs also are predators of small mammals on adjacent pastures; these dogs are usually fed by herdsman with offal offal
1. nonmeat edible products from animal slaughter. Includes brains, thymus, pancreas, liver, heart, kidney, tripes, sausage casings, chitterlings, crackling rind.
2. by-product of milling, called also weatlings, middlings. A high-protein supplement for herbivores. (including liver and lungs) of sheep and yaks during slaughtering season. Necropsy necropsy /nec·rop·sy/ (nek´rop-se) examination of a body after death; autopsy.
examination of a body after death. See also autopsy. of intestines of stray dogs in 1995 in this region showed a 29.5% prevalence for E. granulosus and 11.5% for E. multilocularis (27,28). A recent diagnostic purgation PURGATION. The clearing one's self of an offence charged, by denying the guilt on oath or affirmation.
2. There were two sorts of purgation, the vulgar, and the canonical.
3. study of dogs in this area demonstrated E. multilocularis prevalence of 12% and an E. granulosus prevalence of 8% (29). Foxes are the main sylvatic sylvatic /syl·vat·ic/ (sil-vat´ik) sylvan; pertaining to, located in, or living in the woods.
found in the woods; occurring in animals of the forest. hosts of E. multilocularis, and both the Tibetan fox The Tibetan Fox (Vulpes ferrilata), also called the Tibetan Sand Fox or simply the Sand Fox, is a species of true fox that inhabits the high Tibetan Plateau in Nepal, China, and India, up to altitudes of about 5300 m. (Vulpes ferrilata) and the red fox (V. vulpes) are common on the Qinghai-Tibet plateau. A previous report showed a high prevalence of E. multilocularis in the Tibetan fox (59.1%) and red fox (57.1%) (28) in this area. Furthermore, Qiu et al. observed in 1995 the existence of E. strobilae in Tibetan foxes with morphologic characteristics distinct from E. multilocularis adults but considered it to be a variant of E. multilocularis. These specimens and new samples have been shown to be a new species of taeniid cestode cestode: see Platyhelminthes; tapeworm. belonging to the genus E. Rudolphi (30). However, whether the new species is involved in the transmission of a third form of human echinococcosis in this region has yet to be determined.
This study was supported by the Ecology of Infectious Disease Infectious disease
A pathological condition spread among biological species. Infectious diseases, although varied in their effects, are always associated with viruses, bacteria, fungi, protozoa, multicellular parasites and aberrant proteins known as prions. Program of the National Institutes of Health and National Science Foundation, USA (1R01 Two1565-01) and by the Sichuan Provincial Department of Health, China.
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Li Tiaoying, * Qiu Jiamin, * Yang Wen, * Philip S. Craig, * Chen Xingwang, * Xiao Ning, * ([double dagger]) Akira Ito, (([double dagger]) Patrick Giraudoux, ([section]) Mamuti Wulamu, ([double dagger]) Yu Wen, * and Peter M. Schantz ([paragraph])
* Sichuan Centers for Disease Control and Prevention, Chengdu, Sichuan Province, People's Republic of China; ([dagger])) University of Salford The University of Salford is a university situated in the city of Salford in Greater Manchester, England, United Kingdom. It was founded in 1896 as the Royal Salford Technical Institute, and gained its Royal Charter and full university status in 1967. , Salford, United Kingdom; ([double dagger]) Asahikawa Medical College, Asahikawa, Japan; ([section]) World Health Organization Collaborating Centre for the Prevention and Treatment of Alveolar Echinococcosis, Universite de Franche-Comte, Besancon, France; and ([paragraph]) Centers for Disease Control and Prevention, Atlanta, Georgia, USA
Address for correspondence: Qiu Jiamin, Department of Echinococcosis and Cysticercosis cysticercosis /cys·ti·cer·co·sis/ (sis?ti-ser-ko´sis) infection with cysticerci. In humans, infection with the larval forms of Taenia solium.
n. Control, Institute of Parasitic Diseases, Sichuan Centers for Disease Control and Prevention, Chengdu 610041, Sichuan Province, People's Republic of China; fax: 86-28-8543-8409; email: firstname.lastname@example.org
Dr Tiaoying is an assistant at the Institute of Parasitic Diseases, Sichuan Centers for Disease Control and Prevention. Her research interests include epidemiologic study, chemotherapy, and serodiagnosis of echinococcosis, particularly ultrasound diagnosis.
Table 1. Serologic results for screened study participants with a suspected lesion of alveolar (AE) or cystic (CE) echinococcosis at ultrasound examination * Serology with rEm18 No. tested No. positive Ultrasound image No. cases sera sera Typical image of AE ([double dagger]) 163 102 101 Image of suspected AE Nodular lesion 26 25 16 Calcified lesion 20 14 8 Image of CE CL 10 9 0 CE1 75 42 4 CE2 54 25 3 CE3 23 18 3 CE4 48 26 2 CE5 6 3 0 Total 425 264 137 Serology with EgCF ([dagger]) No. tested No. positive Ultrasound image sera sera Typical image of AE ([double dagger]) 94 93 Image of suspected AE Nodular lesion 25 24 Calcified lesion 20 11 Image of CE CL 8 5 CE1 60 55 CE2 38 38 CE3 16 16 CE4 34 26 CE5 5 5 Total 300 273 * 27.5% of study population refused to provide blood samples for serology. The data only include those study participants with a suspected lesion of AE or CE; other abnormal findings observed at hepatic ultrasound examination, such as hemangioma, biliary cyst, and gallstone, are not presented. ([dagger]) EgCF, Echinococcus granulosus hydatid cyst fluid. ([double dagger]) Typical image of AE is a nonhomogeneous, hyperechoic structure with or without a central necrotic cavity. Table 2. Prevalence of echinococcosis determined by abdominal ultrasound in 26 villages, Shiqu County * No. cases (%) No. Township Village examined AE CE Total Yiniu Benri1 88 9 (10.2) 3 (3.4) 12 (13.6) Benri2 77 4 (5.2) 0 4 (5.2) Benri3 57 5 (8.8) 0 5 (8.8) Jiefang1 64 5 (7.8) 4 (6.3) 9 (14.1) Jiefang2 83 11 (13.3) 2 (2.4) 13 (15.7) Yiniu1 137 12 (8.8) 6 (4.4) 18 (13.1) Yiniu2 87 10 (11.5) 1 (1.1) 11 (12.6) Subtotal 593 56 (9.4) 16 (2.7) 72 (12.1) Mengsha Mengsha1 52 3 (5.8) 6 (11.5) 9 (17.3) Mengsha2 39 0 2 (5.1) 2 (5.1) Mengsha3 33 2 (6.1) 2 (6.1) 4 (12.1) Xinrong1 95 12 (12.6) 7 (7.4) 19 (20.0) Xinrong2 22 1 (4.5) 1 (4.5) 2 (9.1) Xinrong3 30 2 (6.7) 3 (6.3) 5 (16.7) Subtotal 271 20 (7.4) 21 (7.7) 41 (15.1) Arizha Arizha1 48 1 (2.1) 3 (6.3) 4 (8.3) Arizha2 33 2 (6.1) 4 (12.1) 6 (18.2) Arizha3 59 5 (8.5) 0 5 (8.5) Arizha4 62 5 (8.1) 1 (1.6) 6 (9.7) Arizha5 35 5 (14.3) 0 5 (14.3) Arizha6 44 3 (6.8) 2 (4.5) 5 (11.4) Arizha7 42 3 (7.1) 1 (2.4) 4 (9.5) Subtotal 323 24 (7.4) 11 (3.4) 35 (10.8) Xiazha Xiazha 266 10 (3.8) 13 (4.9) 23 (8.6) Ase 104 5 (4.8) 6 (5.8) 11 (10.6) Taxu 153 8 (5.2) 12 (7.8) 20 (13.1) Subtotal 523 23 (4.4) 31 (5.9) 54 (10.3) Qiwu Qiwu 219 2 (0.9) 16 (7.3) 18 (8.2) Getuo 78 0 3 (3.8) 3 (3.8) Juewu 26 1 (3.8) 2 (7.7) 3 (11.5) Subtotal 323 3 (0.9) 21 (6.5) 24 (7.4) Total 2033 126 (6.2) 100 (4.9) 226 (11.1) * Calculations of village prevalence were based on a lower number of participants than the total study population because 1,166 study participants, including public servants, teachers, businessmen working in the area, and additional herdsmen from other townships in the vicinity of Shiqu County also participated in this survey. AE, alveolar echinococcosis, CE, cystic echinococcosis. Table 3. Human prevalence of echinococcosis by patient occupation * No. cases (%) Occupation No. examined CE AE Total Herdsman 1,692 162 (9.6) 160 (9.5) 322 (19.0) Parttime herdsman 79 8 (10.1) 2 (2.5) 10 (12.7) Farmer 35 0 1 (2.9) 1 (2.9) Student 611 8 (1.3) 9 (1.5) 17 (2.8) Public servant 315 11 (3.5) 9 (2.9) 20 (6.3) Employee 69 3 (4.3) 0 3 (4.3) Businessman 17 1 (5.9) 1 (5.9) 2 (11.8) Preschooler 101 3 (3.0) 0 3 (3.0) Illiterate child 63 8 (12.7) 1 (1.6) 9 (14.3) Others 217 12 (5.5) 15 (6.9) 27 (12.4) Total 3,199 216 (6.8) 198 (6.2) 414 (12.9) * CE, cystic echinococcosis; AE, alveolar echinococcosis. Table 4. Human prevalence of echinococcosis by patient ownership of dogs, Sichuan Province, China * No. cases (%) No. examined No. owned dogs persons CE AE Total 0 496 22 (4.4) 19 (3.8) 41 (8.3) 1 889 67 (7.5) 65 (7.3) 132 (14.8) 2 835 61 (7.3) 66 (7.9) 127 (15.2) 3 414 38 (9.2) 29 (7.0) 67 (16.2) [greater than or 177 19 (10.7) 14 (7.9) 33 (19.2) equal to] 4 Total 2,811 207 (7.4) 193 (6.9) 400 (14.2) * CE, cystic echinococcosis; AE, alveolar echinococcosis.