[The human body burden of polychlorinated biphenyls in serum of residents in an area from Hubei Province].

Concentrations of dioxin-like polychlorinated biphenyls (dl-PCBs) and non-dioxin-like PCBs (ndl-PCBs) in 26 serum samples of the residents from Hubei Province were analyzed via high-resolution gas chromatograph tandem high-resolution mass spectrometer (HRGC-HRMS) method. Total concentrations of twelve dl-PCBs (Σdl-PCBs) were in range of 366.30-4 945.77 pg/g fat, with the mean value (2 093.76 pg/g fat), and PCB 118 was the predominant congener. For six ndl-PCBs, total concentrations (Σndl-PCBs) were in range of 2 671.32-20 626.26 pg/g fat (mean 12 505.45 pg/g fat), and PCB 153 was the predominant congener. Mean concentration of Σdl-PCBs were significantly and positively associated with age (rs=0.574, P=0.002). The mean World Health Organization toxicity equivalent (WHO-TEQ) of dl-PCBs (ΣTEQdl-PCBs) were range from 0.07 to 8.69 pg/g fat.

Characterization of antibody and memory T-cell response in H7N9 survivors: a cross-sectional analysis.

OBJECTIVES: Despite the importance of immunological memory for protective immunity against viral infection, whether H7N9-specific antibodies and memory T-cell responses remain detectable years after the original infection is unknown. METHODS: A cross-sectional study was conducted to investigate the immune memory responses of H7N9 patients who contracted the disease and survived during the 2013-2016 epidemics in China. Sustainability of antibodies and T-cell memory to H7N9 virus were examined. Healthy individuals receiving routine medical examinations in a physical examination centre were recruited as control. RESULTS: A total of 75 survivors were enrolled and classified into four groups based on the time elapsed from illness onset to specimen collection: 3 months (n = 14), 14 months (n = 14), 26 months (n = 28) and 36 months (n = 19). Approximately 36 months after infection, the geometric mean titres of virus-specific antibodies were significantly lower than titres in patients 3 months after infection, but 16 of 19 (84.2%) survivors in the 36-month interval had microneutralization (MN) titres ≥40. Despite the overall declining trend, the percentages of virus-specific cytokine-secreting memory CD4+ and CD8+ T cells remained higher in survivors at nearly all time-points in comparison with control individuals. Linear regression analysis showed that severe disease (mean titre ratio 2.77, 95% CI 1.17-6.49) was associated with higher haemagglutination inhibition (HI) titre and female sex for both HI (1.92, 1.02-3.57) and MN (3.33, 1.26-9.09) antibody, whereas female sex (mean percentage ratio 1.69, 95% CI 1.08-2.63), underlying medical conditions (1.94, 95% CI 1.09-3.46) and lack of antiviral therapy (2.08, 95% CI 1.04-4.17) were predictors for higher T-cell responses. CONCLUSIONS: Survivors of H7N9 virus infection produced long-term antibodies and memory T-cell responses. Our findings warrant further serological investigation in general and high-risk populations and have important implications for vaccine design and development.

[Exposure to disinfection by-products during gestation and newborns' small for gestational age].

Objective: To explore the associations between exposure to chlorination disinfection by-products (CDBPs) during gestation and newborns' small for gestational age (SGA). Methods: During April 2010 to July 2012, a total of 3 903 pregnant women who lived in a district with the same water treatment plant in Wuhan, China were recruited to this perspective study. Information about demographic characteristics of pregnant women and their newborns was collected. The tap water samples were monthly collected for 28 months in 3 different sites, with 84 samples, and 4 kinds of trihalomethanes (THMs)(chloroform (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and bromoform (TBM)) and 2 kinds of chlorohaloacetic acids (HAAs) (trichloroacetic acid (TCAA), dichloroacetic acid (DCAA)) were determined. The pregnant women were divided into 4 groups(Q1 to Q4) by quartile method according to their exposure level of CDBPs. Binary Logistic regression models were used to assess the associations between exposure to CDBPs during gestation and newborns' small for gestational age. Results: The average weight of all the newborns was (3 310.19±389.91) g, of which 169 (4.33%) were SGA. The median concentrations of TCM, BDCM, bromo-THMs, total THMs, TCAA, and DCAA during the whole pregnancy were 18.07, 4.93, 8.51, 26.74, 10.65, and 13.77 µg/L, respectively. Binary Logistic regression analysis showed dose-response relationships between elevated TCM and total THMs during the whole gestation and compared with Q1 group, while there was a increased risk of SGA in Q4 group, and OR(95%CI) was 1.87 (1.01-3.49) , 2.30 (1.22-4.35) , respectively (P for trend equaled to 0.044, 0.015). Compare with Q1 group, there also be positive associations between exposure to TCAA (Q4 group) during first-trimester and the whole gestation and SGA, while OR(95%CI) was 2.16 (1.19-3.91) (P for trend equaled to 0.015). Conclusion: Exposure to CDBPs during gestation might increase the risk of newborns' SGA.

[Epidemiology of scrub typhus and influencing factors in Yunnan province, 2006-2013].

Objective: To understand the epidemiological characteristics of scrub typhus and influencing factors in Yunnan province, and provide further information for the prevention and control of scrub typhus. Methods: Based on the incidence data of scrub typhus reported in Yunnan from 2006 to 2013, the epidemiological characteristics of scrub typhus were analyzed and related environmental factors were identified with panel negative binomial regression model. Results: A total of 8 980 scrub typhus cases were reported during 2006-2013 in Yunnan. The average annual incidence was 2.46/100 000, with an uptrend observed. Natural focus expansion was found, affecting 71.3% of the counties in 2013. The epidemic mainly occurred in summer and autumn with the incidence peak during July-October. The annual incidence was higher in females than in males. More cases occurred in children and farmers, the proportions of cases in farmers and pre-school aged children showed an obvious increase. Panel negative binomial regression model indicated that the transmission risk of scrub typhus was positive associated with monthly temperature and monthly relative humidity. Furthermore, an "U" pattern between the risk and the increased coverage of cropland and grassland as well as an "inverted-U" pattern between the risk and increased coverage of shrub were observed. Conclusion: It is necessary to strengthen the scrub typhus surveillance in warm and moist areas as well as the areas with high coverage of cropland and grassland in Yunnan, and the health education in children and farmers who are at high risk.

[Surveillance as an effective approach to infectious diseases control and prevention].

Infectious disease surveillance have played an important role in the national diseases prevention and control strategies. In line with the reporting system, infectious disease surveillance has been greatly improved and played pivotal role in preventing epidemics since 1949 in China. To date, surveillance remains an effective approach to infectious disease control and prevention because of the global serious situation. In this column "infectious disease surveillance" , we have involved articles as systematic analysis of surveillance data and solid evidence related to the development of strategies and measures for infectious diseases control and prevention.

[Study on the epidemiological characteristics and influencing factors of scrub typhus in the autumn-winter natural foci, from 2006 to 2013].

OBJECTIVE: To investigate the spatiotemporal expansion and risk factors of scrub typhus (ST) in Shandong, Jiangsu and Anhui provinces. METHODS: Based on the reported cases in Shandong and Jiangsu from 2006 to 2013, and Anhui from 2008 to 2013 epidemiological characteristics of ST and associated environmental factors were analyzed, using the panel negative binomial regression model. RESULTS: A total of 2 968, 2 331 and 3 447 ST cases were respectively reported in Shandong, Jiangsu and Anhui during 2006-2013, with the average annual incidence rates as 0.39, 0.38 and 0.94 per 100 000 population. Uptrend in Shandong and Jiangsu, but a slight rollback seen in Anhui were observed. Expansion of natural foci was found in the 3 provinces, with affected counties accounted for 38.0%, 48.2% and 46.5% in Shandong, Jiangsu and Anhui, respectively in 2013. Cases were clustered in autumn but with a peak of single epidemic appeared in October or November, in all the 3 provinces. More female and elderly patients were seen, than in the other age groups, in all the 3 provinces. Majority of the cases were farmers, with an increasing trend in incidence, in all these provinces, followed by housekeepers in Shandong and preschool children in Anhui. The risk factors of transmission in all the 3 provinces were negatively associated with the monthly precipitation, and showing an " inverted-U" pattern in association with monthly temperature. A positive relationship between the risk of transmission and monthly relative humidity was found in Shandong and Jiangsu provinces. However, an " inverted-U" pattern between the risk of transmission and the monthly sunshine hour, appeared in Shandong and Anhui provinces. The incidence of Scrub typhus in Shandong was also positively related to the coverage of forest. CONCLUSION: Surveillance programs and health education measures should focus on the warm and moist areas in all the 3 provinces, and also on forestry areas in Shandong. Health education and prevention on mite-bite should be targeted, especially on high-risk populations as the elderly and farmers, in the 3 provinces. Housekeepers in Shandong and children in Anhui should also be under special concern.

Epidemiological and clinical characteristics of severe fever with thrombocytopenia syndrome (SFTS) in China: an integrated data analysis.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease that was caused by a novel bunyavirus, SFTSV. The study aimed to disclose the epidemiological and clinical characteristics of SFTSV infection in China so far. An integrated clinical database comprising 1920 SFTS patients was constructed by combining first-hand clinical information collected from SFTS sentinel hospitals (n = 1159) and extracted data (n = 761) from published literature. The considered variables comprised clinical manifestations, routine laboratory tests of acute infection, hospitalization duration and disease outcome. SFTSV-IgG data from 19 119 healthy subjects were extracted from the published papers. The key clinical variables, case-fatality rate (CFR) and seroprevalence were estimated by meta-analysis. The most commonly seen clinical manifestations of SFTSV infection were fever, anorexia, myalgia, chill and lymphadenopathy. The major laboratory findings were elevated lactate dehydrogenase, aminotransferase, followed by thrombocytopenia, lymphocytopenia, elevated alanine transaminase and creatine kinase. A CFR of 12·2% was estimated, significantly higher than that obtained from national reporting data, but showing no geographical difference. In our paper, the mortality rate was about 1·9 parts per million. Older age and longer delay to hospitalization were significantly associated with fatal outcome. A pooled seroprevalence of 3·0% was obtained, which increased with age, while comparable for gender. This study represents a clinical characterization on the largest group of SFTS patients up to now. A higher than expected CFR was obtained. A wider spectrum of clinical index was suggested to be used to identify SFTSV infection, while the useful predictor for fatal outcome was found to be restricted.

Polymorphism of X-linked CD40 ligand gene associated with pulmonary tuberculosis in the Han Chinese population.

Among those developing tuberculosis (TB) after exposure to Mycobacterium tuberculosis, approximately 70% are males. Host genetic variation, particularly immune-related genes on the X chromosome, may contribute to sex-specific differences in TB incidences. To study whether X-linked gene variation is associated with sex-specific presentation of pulmonary TB (pTB), three single-nucleotide polymorphisms (SNPs) of the TLR8, CD40LG and IRAK1 genes on the X chromosome were genotyped in 923 patients and 1033 healthy individuals of the Han Chinese population. Frequencies of the variants were analyzed independently as well as in their combinations. CD40LG rs3092923 and its combined effects with the other two SNPs were associated with an increased risk of pTB only in males. In males, the rs3092923 genotype C/(-) conferred relative protection (odds ratio (OR): 0.52, 95% confidence interval (CI): 0.35-0.78, Pcorr.=0.0045) and the combined effects of three SNPs increased gradually as the number of risk alleles increased (OR: 2.58, 2.83 and 2.96 for one, two and three risk alleles, respectively). For the remaining SNPs, significance was obtained only for the AA genotype of IRAK1 rs3027898 in the combined and female-only analysis. Our results indicate a role of a CD40LG variant and its combined effects with distinct TLR8 and IRAK1 variants in susceptibility to pTB in males.

Discrimination of novel bunyavirus infection using routine laboratory test.

The wide epidemic and high case fatality rate have made severe fever with thrombocytopenia syndrome (SFTS) a significant public health problem. The diagnosis and discrimination of SFTS virus (SFTSV) infection at an early stage of the disease is important for treatment choice. A prospective study was performed in an SFTS reference hospital during 2011-2013. Suspected SFTS patients were recruited and prospectively observed. Comparison between SFTSV-positive and -negative patients was made to identify the parameters that were related to positive detection by discriminant and classification tree analysis. A total of 538 SFTSV-positive and 396 negative patients were recruited and observed. Multiple logistic regression models demonstrated the significant parameters associated with positive detection, including decreased platelet counts and elevated aspartate aminotransferase (AST) level during the first stage (1∼4 days), decreased white blood cell and platelet counts, elevated creatine kinase (CK) and AST levels during the second stage (5∼7 days), and older age, decreased consciousness and elevated CK and AST during the third stage (8-11 days). The classification trees disclosed that the significant predictors for positive SFTSV detection were AST >50.6 U/L and AST/alanine transaminase (ALT) >1.3 at the first stage, CK >257 U/L or 57.7 U/L < CK ≤98.5 U/L with AST/ALT >1.6 at the second stage, as well as CK >630.7 U/L or 114.3 U/L < CK ≤630.7 U/L with decreased consciousness at the third stage. In making the clinically probable diagnosis of SFTS, the supplementation of AST and CK evaluations might remarkably improve the diagnostic capacity of routine laboratory tests, while the leukopenia is of limited use.

Epidemic and molecular evolution of human bocavirus in hospitalized children with acute respiratory tract infection.

Human bocavirus (HBoV) is a novel parvovirus, often associated with respiratory tract diseases in children. This study explored the epidemiological characteristics and molecular evolution of HBoV-1 in southeastern China. Nasopharyngeal aspirates were collected from children admitted to hospital with acute respiratory tract infections. HBoV-1 was detected using real-time reverse transcription polymerase chain reaction and further characterized by complete genome sequences analysis. Among the 3,022 recruited children, 386 (12.77%) were HBoV-1-positive and 300 (77.72%) had co-detection with other respiratory viruses. Seasonal prevalence peaked in summer. HBoV-1 presence was significantly associated with asthma attack [odds ratio = 1.74; 95 % confidence interval: 1.30, 2.31; p < 0.001]. Similar results were obtained when either single detection or co-detection of HBoV-1 was considered, demonstrating the minor impact of co-detection on the clinical characteristics or epidemic pattern. Phylogenetic analysis based on the complete genome sequences showed that all the HBoV-1 sequences clustered together and no branch was formed that was supported by bootstrap value ≥ 750. The overall evolutionary rate of the complete genome of HBoV-1 was estimated at 1.08 × 10(-4) nucleotide substitutions per site per year (s/s/y) [95% highest probability density: (0.40-1.86) × 10(-4) s/s/y]. Selective pressure analysis showed that all the ω-values were less than 1, suggesting that HBoV-1 was under negative selective pressure. Site-by-site analysis identified the codon site 40 of the VP1 gene under positive selection. In conclusion, our study disclosed the epidemiological and genetic dynamics of HBoV-1 epidemics in southeastern China in the most recent 3 years, the information of which might help to further improve our understanding of HBoV-1 infection and guide better surveillance and control strategies in the future.

Lyme borreliosis caused by diverse genospecies of Borrelia burgdorferi sensu lato in northeastern China.

The variety of Borrelia burgdorferi sensu lato (B. burgdorferi) genospecies leads to distinction in clinical manifestations of Lyme borreliosis (LB). There are reports of LB clinical characteristics in China, where the B. burgdorferi genospecies in ticks and animal hosts are different from those in Europe and North America. During May to September in 2010 and 2011, all patients who had erythema migrans (EM, more than 5 cm in diameter) after a recent tick-bite, and sought medical care at Mudanjiang Forestry Central Hospital, Heilongjiang Province of northeastern China, were enrolled in the study. Specific PCR was used to determine the B. burgdorferi genospecies in the disseminated patients. Of 265 EM patients, B. burgdorferi DNA was detected in blood specimens from 15 of 55 disseminated patients. Sequence analyses of 5S-23S rRNA, flagellin, ospC, 16S rRNA and ospA genes revealed that 11 patients were infected with Borrelia garinii, three with Borrelia afzelii and one with Borrelia valaisiana-related genospecies. Among 15 patients, 40%, 13.3% and 13.3% manifested pruritus, pain and ulceration, respectively. Systemic symptoms, arthralgia or a swollen joint and lymphadenopathy were observed in 26.7%, 13.3% and 6.7% patients, respectively. In northeastern China, three genospecies of LB patients were detected. The B. burgdorferi genospecies identified in this study was predominantly B. garinii. A case infected with B. valaisiana-related genospecies was reported for the first time.

An approach to estimate the number of SARS cases imported by international air travel.

The worldwide spread of severe acute respiratory syndrome (SARS) raised questions about the risk of importation of such infection, in particular by air travel. Entry screening was implemented in some countries although poor evidence on its effectiveness is reported. We developed a model to estimate the number of imported SARS cases between regions, using the 2003 SARS epidemic data to apply this model for two scenarios: from Beijing to Frankfurt and from Hong Kong to London. We back-calculated the data to estimate individuals' time of infection and built a model where every individual has a probability of being isolated, of traveling, and of being undetected at arrival. The findings, consistent with what was observed in 2003, suggest that entry screening does not affect the predicted number of imported cases. Inversely, importation depends on the transmission dynamic in the country of origin (including control measures in place) and on the intensity of air travel between regions.

Sequence variations in the MBL gene and their relationship to pulmonary tuberculosis in the Chinese Han population.

SETTING: The mannan binding lectin (MBL) gene is thought to play a role in human innate immune response to tuberculosis (TB) infection. OBJECTIVE: To investigate the possible association between MBL sequence variants and TB infection in the Chinese Han population. DESIGN: A total of 152 male pulmonary tuberculosis (PTB) patients and 293 healthy male subjects were recruited. Six MBL single nucleotide polymorphisms (SNPs) (A/B, A/C, A/D, H/L, Y/X and P/Q) were genotyped and haplotyped using the combined analysis of polymerase chain reaction using sequence-specific primers (PCR-SSP) and the PCR-sequence specific oligonucleotide probe (PCR-SSOP) assay. The genotype and haplotype frequencies were compared between TB cases and controls using an unconditional logistic regression model. RESULTS: Neither the genotypes nor the haplotypes of the five loci were significantly associated with the disease when considered individually. After the haplotypes were regrouped, however, the XB haplotype group coding for diminished MBL levels was present at a significantly higher frequency in the patients compared with the YA group (OR 1.57, 95% CI 1.02-2.41, P < 0.05). CONCLUSION: No convincing evidence of association between MBL sequence variants and PTB was observed individually, although the low-producing XB haplotype group may serve as a minor risk factor for PTB infection in the male Chinese Han population.

VDR and NRAMP1 gene polymorphisms in susceptibility to pulmonary tuberculosis among the Chinese Han population: a case-control study.

OBJECTIVE: To explore the potential role of vitamin D receptor (VDR) gene and natural-resistance-associated macrophage protein 1 (NRAMP1) gene polymorphisms in susceptibility to pulmonary tuberculosis (PTB) in the Chinese Han population. DESIGN: In an unmatched case-control study, 120 well defined PTB patients and 240 unrelated normal controls were enrolled. Information on potential risk factors of PTB was collected using a standard questionnaire. Genetic polymorphisms of VDR gene (TaqI and FokI) and NRAMP1 gene (INT4, D543N and 3'UTR) were analysed using PCR and RFLP. Unconditional logistic regression was performed, and odds ratios (ORs), their 95% confidence intervals (CI) and P values were estimated using maximum likelihood methods. RESULTS: Univariate analysis demonstrated that FokI-ff homozygotes, D543N G/A and 3'UTR TGTG+/del heterozygotes occurred more frequently in patients than in controls. The crude ORs were 2.345 (95%CI 1.222-4.499), 2.590 (95%CI 1.043-6.434) and 1.890 (95%CI 1.171-3.051), respectively, compared with their corresponding common genotypes. The P values were 0.033, 0.041 and 0.030, respectively. After adjusting for exposure history and BCG immunisation in the multivariate analysis, the adjusted ORs were 4.625 (95%CI 1.737-12.312), 2.415 (95%CI 1.079-8.759) and 2.187 (95%CI 1.146-4.175), with P values of 0.002, 0.036 and 0.018, respectively. Neither univariate nor multivariate analysis disclosed any significant association between the disease and TaqI or INT4. CONCLUSIONS: Polymorphisms in the VDR and NRAMP1 gene are statistically associated with susceptibility to PTB in the Chinese Han population.

Granulocytic Ehrlichiae in Ixodes persulcatus ticks from an area in China where Lyme disease is endemic.

A total of 372 adult Ixodes persulcatus ticks were collected from vegetation in a forest area of Heilongjiang Province in northeastern China, where Lyme disease is known to be endemic. The ticks were examined for the presence of granulocytic ehrlichiae by heminested PCR with primers derived from the 16S rRNA gene. Of 310 ticks obtained from the Dahe forestry farm, two pools (each containing 5 ticks) were found positive, with a minimum infection rate of 0.6%. Ehrlichial DNA was also detected in one female (1.6%) of 62 ticks collected from the Yulin forestry farm. The overall minimum infection rate of the 372 I. persulcatus adults was 0.8%. The nucleotide sequences of 919-bp PCR products from the three positive tick specimens were identical to each other and very closely related to the members of the Ehrlichia phagocytophila genogroup. This is the first identification of granulocytic ehrlichiae in ticks in Asia and the first report of infection in I. persulcatus anywhere.

Identification of Ehrlichia chaffeensis by nested PCR in ticks from Southern China.

A total of 717 ticks collected from southern China were examined by nested PCR for the presence of Ehrlichia chaffeensis. Sixteen (55. 2%) of 29 adult Amblyomma testudinarium ticks and 28 (11.7%) of 240 adult and at least 4.2% of 215 nymphal (pooled specimens) Haemaphysalis yeni ticks tested positive. Four other species of ticks were negative. Selected positive amplicons were confirmed by DNA sequencing.

Efficacy of ivermectin in the treatment of Wuchereria bancrofti infection: a model-based analysis of trial results.

Ivermectin is a promising drug for the treatment of lymphatic filariasis. A meta-analysis of trials investigating the effects of a single treatment suggested a dose-dependent effect on the production of microfilariae (mf) by adult Wuchereria bancrofti parasites. A mathematical model that describes the parasite dynamics in the human host and the impact of ivermectin treatment is presented and its outputs compared with these trials. The calculated trend in mf density after treatment appears to be particularly sensitive to the assumption about the mean life-span of mf. Adopting 0.5-2 years as a range of plausible values for this mf life-span, the model is used to estimate the impact of treatment on the parasite. It is found that irrespective of dosage, ivermectin eliminates 100% of the blood mf from a patient. Furthermore, at a dosage level of 400 micrograms/kg a single treatment irreversibly reduces the mf production of the adult parasites by at least 65%. For a dosage of 200 micrograms/kg this reduction is at least 35%. No such effect can be concluded from the results of trials using lower dosages.

Ivermectin for the chemotherapy of bancroftian filariasis: a meta-analysis of the effect of single treatment.

The efficacy and safety of ivermectin in the treatment of filariasis due to Wuchereria bancrofti was assessed by a meta-analysis of the results from 15 published clinical trials. Seven hundred and forty-eight microfilaraemic patients were enrolled in 7 dose-finding and 8 comparative studies. Administered as a single dose, ivermectin induced nearly complete clearance of microfilariae from the blood from the first day to 30 days post-treatment, followed by gradual recurrence of microfilaraemia and increase in its intensity. Higher doses of ivermectin showed greater clearance effects and maintained lower microfilaraemia levels for a longer time. The adverse reactions caused by the drug were flu-like, transient, generally mild and well tolerated by patients. The frequency and intensity of adverse reactions were strongly associated with pretreatment microfilaria counts in the blood, but independent of dose. The findings of the meta-analysis suggest that ivermectin given at a single annual dose of 200 micrograms/kg body weight or higher, whether or not in combination with DEC, has great potential for therapeutic strategies to control bancroftian filariasis.

Seroprevalence and risk factors of human cysticercosis in a community of Shandong, China.

A community-based seroepidemiologic survey on Taenia solium cysticercosis in humans was carried out in Shandong Province, China. Blood specimens from 2,898 residents were collected and examined for anti-cysticercus antibody. Information on demographic and potential risk factors was obtained using a standardized questionnaire. The overall seroprevalence of cysticercosis was 3.2%. Seropositivity tended to increase with age ranging from 1.8% in children under 6 years of age to 5.7% in those over 60 years old. Distance between village residence and the town of the community was negatively associated with seropositivity (Chi-square for trend test p = 0.02). Multivariate logistic regression analysis identified four risk factors for cysticercosis infection in the community: defecating indiscriminately (OR = 1.35, 95% CI 1.01-1.81), being unable to identify diseased pork (OR = 4.09, 95% CI 1.53-10.97), raising pigs (OR = 1.36, 95% CI 1.09-1.69), and more than 60 years old (OR = 1.49, 95% CI 1.10-2.02. These findings have implications for developing appropriate strategies for the control of Taenia solium cysticercosis in the community.

Epidemiological surveillance of filariasis after its control in Shandong Province, China.

Shandong Province used to be the highly endemic area of Wuchereria bancrofti. Culex pipiens pallens was the main mosquito vector. After about 30 years of large scale anti-filariasis control campaign, filariasis was controlled throughout the province in 1983. Since then, extensive cross-sectional and consecutive longtitudinal surveillances have been carried out. Parasitological and entomological data indicated that the microfilaremia rate of the human population, and the natural infection rate of mosquito vector kept declining, with many villages dropping to zero; no children under ten were infected. Serological surveillance showed that antifilarial antibody had fallen to the same level as that in non-endemic areas 10-15 years after control. In addition, patients with chronic manifestations were reduced in number. It is suggested that the achievement in filariasis control in Shandong Province is stable: the transmission of filariasis has been interrupted. However, there are still a few residual microfilaremia cases, which may bring about new infection under conditions favorable for transmission. Infectious sources may be introduced by population movements from a neighboring province where filariasis is still endemic at present. Moreover, new cases with chronic manifestations, especially chyluria, continually emerge. So systematic surveillance should be continued and proper control measures must be taken to eventually wipe the disease out of the province.