| BACKGROUND AND OBJECTIVEParagonimiasis is a kind of common parasitic zoonoses. It distributes widely and does severely harm to people's health. It can cause the symptoms such as chest ache, cough, expectoration and moving subcutaneous tubercle. When paragonimus enter into brain, the patient would have a headache, vomit, epilepsy even hemiplegia. At present, paragonimiasis mainly exist in some countries and areas of Asia, Latin America and Africa. It is estimated that there are 20 million paragonimus infection cases in the world. It is proved through investigations that paragonimiasis exists in 22 provinces of China and the number of population that be threatened by the disease is about 185 million.The topography, weather and people's dietetic habit of Ningbo area are fit for the transmission of paragonimiasis. Some part of Ningbo area is historical epidemic area of paragonimiasis and the number of paragonimiasis cases has a rising tendencyand the phenomenon of wrong diagnosis often happens in recent years, In this survey, the paragonimiasis cases were collected by the clinic of Ningbo Center for Disease Control and Prevention(CDC) during 2000 to 2004. The distribution of paragonimus metacercaria in crabs and infection rate of paragonimus in counties of Yuyao, Fenghua, Ninghai and Xiangshan were investigated. So we could realize the epidemic situation of paragonimiasis, and provide scientific basis for the clinical treatment and the establishment of the prevention and control measures.MATERIAL AND METHODS1 The surveillant data of paragonimiasis cases : 369 paragonimiasis cases were collected by the clinic of Ningbo CDC in 2000~2004, the diagnosis standard was on the basis of the epidemiological history, clinic symptom and test of dot immunogold filtration assay(DIGFA) or enzyme linked immunosorbent assay(ELISA)2^ The survey of paragonimus metacercaria infection rate in crabs: With the method of standard sampling, Zhangting, Liangnong town of Yuyao, Banzhu town of Fenghua, Meilin town of Ninghai and Xiashen town of Xiangshan were selected as the investigating areas. 992 crabs were caught totally, and their sex, kind and weight were identified one after another. With the method of crashing-sediment, the crabs were checked for paragonimus metacercaria, and the shape of metacercaria was observed. The metacercaria infection rate and the degree of infection were calculated respectively.3> The survey of people's paragonimus infection rate: Lukeng village of Yuyao, Huix and Dong'ao village of Fenghua, Chujia and Xiaoting village of Ninghaiwere selected as the investigating points. 1336 villagers were checked totally. Age and sex were registered, and 3 ml venous blood from forearm of the villagers were taken for paragonimus antibody inspecting with the method of DIGFA. People's infection rate was calculated finally.Collection and statistic analysis of the data: The data of survey and experiment were processed and analyzed with the software of SPSS 13.0 in personal computer after verified. The distribution of clinic paragonimiasis cases, crabs and people were analyzed by the method of descriptive statistics. The relation of crab sex and its paragonimus metacercaria infection rate, people's age and their paragonimus infection rate were analyzed by Pearson's %2 test, the relation of crab weight and its paragonimus metacercaria infection degree was analyzed by the method of linear correlation.RESULTS1 > The surveillant data of paragonimiasis cases in Ningbo CDC ,2000~2004: 1923 suspicious serum samples were detected and 369 positive samples of paragonimus antibody were found. The positive rate was 19.19%. Among 369 paragonimiasis cases, the proportion of male to female is 1:1.15. The minimum age was 1 years old and the maximum was 72 years old, and the average was (35.28±13.04) years old. Most patients come from mountain areas, the number of cases that come from Yinzhou, Fenghua, Yuyao, Ninghai county was 215(58.27%).2^ The survey of paragonimus metacercaria infection rate in crabs: 992 crabs were detected. 582 crabs were male and 410 crabs were female. The categoryof crab in Ningbo area was mainly Sinopotamon chekiangense besides in Fenghua both Sinopotamon chekiangense and S.yangtsekiense were found. The minimum weight of crabs is 3.5g and the maximum is 40g, and the average weight is (15.88±9.28)g. The positive rate of paragonimus metacercaria in crabs was 10.79%( 107/992). 388 metacercarias were found totally, and the average of paragonimus metacercaria number in a crab is 3.63 and in 1 gram crab tissue it is 0.27. In positive crabs the minimum number of metacercaria is 1 and the maximum is 32.There was no significant difference between male crab infection rate and female crab infection rate (^-3313, P>0.05). There was not statistical relation about metacercaria number of positive crab and its weight (r=0.051? P=0.754).3> The survey of people's paragonimus infection rate: 1336 villagers and pupils were investigated. 597 were male and 739 were female. The average of the villagers' age in all investigated points was 53.22~58.04 while the average of the pupils' age was 11.06~ 13.86. 17 positive cases of paragonimus antibody were found in Fenghua, and the total infection rate is 1.27%. There was no significant difference between villagers' infection rate and f pupils' infection rate. All the positive cases ever had the experience of eating uncooked crabs in recent 3 years. No positive case was found in Yuyao and Ninghai county.CONCLUSIONRecently the epidemic area of paragonimiasis still exists in some parts of Ningbo area. The category of paragonimus is mainly paragonimus Westermani, and the second middle host is Sinopotamon chekiangense and S.yangtsekiense, the former is the main kind. In Xiangshan county, some historical paragonimiasisepidemic areas are eliminating gradually. In some parts area of Yuyao and Ninghai county, the epidemic areas still exist, epidemic degree in people has declined magnificently, while in some areas of Fenghua county, the paragonimiasis in second middle host and in people exist as before. Prevention of paragonimiasis should be planned and especially in some special areas, and the hygienic knowledge should be propagated in a long period. |
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