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Biomedical subjects

F Cheng

Publications and source records attributed to F Cheng.

At least 55 records · Page 3Linked to original sources
PubMed1998

Critical care ethics in Hong Kong: cross-cultural conflicts as east meets west.

The practice of critical care medicine has long been a difficult task for most critical care physicians in the densely populated city of Hong Kong, where we face limited resources and a limited number of intensive care beds. Our triage decisions are largely based on the potential of functional reversibility of the patients. Provision of graded care beds may help to relieve some of the demands on the intensive care beds. Decisions to forego futile medical treatment are frequently physician-guided family-based decisions, which is quite contrary to the Western focus on patient autonomy. However, as people acquire knowledge about health care and they become more aware of individual rights, our critical care doctors will be able to narrow the gaps between the different concepts of medical ethics among our professionals as well as in our society. An open and caring attitude from our intensivists will be important in minimizing the cross-cultural conflict on the complex issue of medical futility.

Aged↗
PubMed1998

[Study on the epidemiological characteristics and strategy of surveillance in low endemic areas of malaria in Hubei].

Due to good programs on case finding and control, malaria has decreased to a low level in China. Hence, the existing surveillance program of undertaking blood smear from cases with fever finds very few positives in the millions of examinees. Previously, all blood slides were collected from clinically diagnosed cases of malaria (group 1), suspected malaria cases (group 2), fever of unknown reasons (group 3) or common cold (group 4) in low or moderate malaria endemic areas in Hubei Province. In low prevalence areas, the positive rates on slides were 0.6/10,000 and 0.1/10,000 in group 3 and group 4 while 95.38% of the confirmed malaria cases were from those having clinical malaria or suspected malaria. It is suggested that group 3 and group 4 be dropped from low prevalence areas to encourage greater efficiency in case detection in the clinical and the suspected malaria groups.

Animals↗
PubMed1998

[Comparative study on results of pulmonary tuberculosis surveillance before and during implementation of tuberculosis control project in Ningxia Hui autonomous region].

OBJECTIVE: To understand the effect of the World Bank-loaned tuberculosis control project in Ningxia Hui autonomous region. METHOD: Five counties which can reflect the situation of tuberculosis control in Ningxia were selected for observation, and the same method of surveillance was carried out. The subjects investigated were required to fill in the surveillance and the project forms at the same time, and the data of the tuberculosis control before (1990, 1991) and during (1995, 1996) implementation of the project were compared. RESULT: The registration rate of new smear-positive patients was 20.35 per 100,000 population during the implementation of the project, with a 3.06 times increase compared with that before implementation of the project. The proportion of new smear-positive patients increased from 21.37% to 61.70%, the smear-positive rate of newly registered patients from 22.80% to 35.32%, and the finding rate of new smear-positive patients from 7.97% to 31.11%. The mortality rate of pulmonary tuberculosis decreased by 58.36%. The total impact of finding and treatment increased from 7.60% to 31.90%. CONCLUSION: Satisfactory results have been achieved during the implementation of the project in Ningxia.

China↗
PubMed1997

Biosynthesis of the proteoglycan decorin--transient 2-phosphorylation of xylose during formation of the trisaccharide linkage region.

Phosphorylation of decorin was investigated by incubating a rat fibroblast cell line with radiolabelled phosphate and carbohydrate precursors. There was a transient phosphorylation of the linkage-region saccharides in intracellular decorin prior to assembly of the galactosaminoglycan chain. Phosphorylation gradually increased from xylosylated, galactosyl-xylosylated to galactosyl-galactosyl-xylosylated core protein where all trisaccharide stubs were phosphorylated. Addition of the first glucuronate residue was accompanied by rapid dephosphorylation. Brefeldin A treatment resulted in segregation of galactosaminoglycan synthesis and dephosphorylation. Enzymatic degradation of brefeldin-A-arrested immature proteoglycan with incomplete galactosaminoglycan chain [Moses, J., Oldberg, A., Eklund, E. & Fransson, L.-A. (1997) Eur. J. Biochem., in the press] by using chondroitin AC lyase and chondro-glycuronidase, followed by beta-galactosidase treatment, demonstrated the sequence galactosyl-galactosyl-phosphoxylose. The xylose was resistant to direct periodate oxidation, but sensitive after treatment with alkaline phosphatase, showing that the phosphate was located at C2 of xylose. The transient 2-phosphorylation of xylose may be involved in intracellular transport and/or in the control of modifications of the glycan chain.

Animals↗
PubMed1997

Binding, internalization, and degradation of antiproliferative heparan sulfate by human embryonic lung fibroblasts.

Binding, internalization, and degradation of 125I-labeled, antiproliferative, or nonantiproliferative heparan sulfate by human embryonic lung fibroblasts was investigated. Both L-iduronate-rich, antiproliferative heparan sulfate species as well as L-iduronate-poor, inactive ones were bound to trypsin-releasable, cell-surface sites. Both heparan sulfate types were bound with approximately the same affinity to one high-affinity site (Kd approximately 10(-8) M) and to one low-affinity site (Kd approximately 10(-6) M), respectively. Results of Hill-plot analysis suggested that the two sites are independent. Competition experiments with unlabeled glycosaminoglycans indicated that the binding sites had a selective specificity for sulfated, L-iduronate-rich heparan sulfate. Dermatan sulfate, which is also antiproliferative, was weakly bound to the cells. The antiproliferative effects of heparan and dermatan sulfate appeared to be additive. Hence, the two glycosaminoglycans probably exert their effect through different mechanisms. At concentrations above 5 micrograms/ml (approximately 10(-7) M), heparan sulfate was taken up by human embryonic lung fibroblasts, suggesting that the low-affinity site represents an endocytosis receptor. The antiproliferative effect of L-iduronate-rich heparan sulfate species was also exerted at the same concentrations. The antiproliferative species was taken up to a greater degree than the inactive one, suggesting a requirement for internalization. However, competition experiments with dextran sulfate suggested that both the high-affinity and the low-affinity sites are involved in mediating the antiproliferative effect. Structural analysis of the inactive and active heparan sulphate preparations indicated that although sulphated L-iduronate appears essential for antiproliferative activity, it is not absolutely required for binding to the cells. Degradation of internalized heparan sulfate was analyzed by polyacrylamide gel electrophoresis using a sensitive detection technique. The inactive species was partially degraded, whereas the antiproliferative one was only marginally affected.

Biological Transport↗
PubMed1997

Effects of primer-concentration on uronosyl-epimerization and sulfation patterns in p-hydroxyphenyl-O-beta-D-xylopyranoside-primed galactosaminoglycans produced by skin fibroblasts.

By supplying skin fibroblasts with different concentrations of the galactosaminoglycan chain-primer p-hydroxyphenyl-O-beta-D-xylopyranoside we have produced and recovered glycan-chains that were subsequently radio-iodinated in the hydroxyphenyl group and subjected to sequence analysis by using graded enzymic treatment followed by a combination of gel chromatography and electrophoresis. Fragments extending from the tagged reducing end to the cleavage-point were identified and quantified. Degradation by chondroitin B lyase of chains primed at 0.1 or 0.5 mM xyloside gave profiles indicating a periodic and wave-like distribution of iduronate-containing repeats, with high incidence around positions 2, 5 and onwards, whereas in chains produced at 1.0 mM xyloside the incidence of iduronate was similar in positions 1-4 and then declined. Degradation by chondroitin AC lyase indicated a high incidence of glucuronate in or near the linkage-region. There was a relatively uniform degree of sulfation in chains primed at low xyloside concentration, whereas chains primed at 1.0 mM xyloside gave very heterogeneous charge-patterns in all segments of the chain, including the linkage-region, giving the impression that adequate sulfation, probably at C-4 and at the first opportunity, is necessary to obtain an ordered and periodic epimerization pattern.

Carbohydrate Sequence↗
PubMed1997

The study of IL-1 beta, TNF-alpha, IL-6 gene expression and plasma levels on hemodialysis before and after dialyzer reuse.

OBJECTIVE: To investigate the biocompatibility of dialyzer reuse. METHODS: Twenty-two hemodialysis patients were randomized into cuprophan (CU, 7), polymethylmethacrylate (PMMA, 7) and polysulphone (PS, 8) membrane groups to observe IL-1 beta, TNF-alpha, IL-6 gene expression and their plasma levels by using themselves as control with enzyme-linked immunosorbent assay (ELISA), reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization. RESULTS: Plasma levels of interlukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) were 14.07 +/- 3.32 pg/ml, 67.41 +/- 19.79 pg/ml, 83.67 +/- 40.34 pg/ml; 12.80 +/- 3.01 pg/ml, 49.65 +/- 9.75 pg/ml, 33.36 +/- 12.14 pg/ml and 14.41 +/- 3.16 pg/ml, 80.56 +/- 23.22 pg/ml, 48.14 +/- 16.01 pg/ml, respectively, after patients dialyzed with CU, PMMA and PS membranes. Plasma cytokine levels decreased after reuse compared with those before reuse in each group. But no significant difference was found between them (P > 0.05); the levels of IL-1 beta, TNF-alpha, IL-6 gene expression after reuse were 5.61 +/- 0.33, 2.11 +/- 0.12, 5.04 +/- 0.19%; 2.43 +/- 0.19, 1.29 +/- 0.11, 3.48 +/- 0.20% and 2.48 +/- 0.20, 1.24 +/- 0.11, 3.22 +/- 0.20% respectively by in situ hybridization, and 0.92 +/- 0.07, 0.63 +/- 0.05, 0.53 +/- 0.05; 0.61 +/- 0.06, 0.47 +/- 0.04, 0.37 +/- 0.03 and 0.59 +/- 0.05, 0.44 +/- 0.04, 0.38 +/- 0.03 by RT-PCR, respectively. After reuse there was significant decrease as compared with that before reuse (P < 0.001, P < 0.005 and P < 0.05, respectively). CONCLUSIONS: This suggested reprocessing dialyzer with formaldehyde reduced cytokine release and gene expression in peripheral blood mononuclear cells and enhanced dialyzer biocompatibility. It would be beneficial to reduce the dialysis cost and may reduce the complication related to a long term hemodialysis.

Adult↗
PubMed1997

Significance of P-selectin expression in human glomerulonephritis.

OBJECTIVE: To examine the relationship between P-selectin expression and human glomerulonephritis. METHODS: P-selectin expression was investigated in renal biopsies of glomerulonephritis patients (n = 133) by immunohistochemical and in situ hybridization analyses. They were divided into three groups based on the degrees of cells proliferation or sclerosis. Group I: histological lesions in glomeruli are mild (n = 23); Group II: glomerular cells proliferation is prominent (n = 91); Group III: glomerular sclerosis is severe (n = 19). The Kruskal-Wallis test, Chisquare test and Spearman's correlation were used in our study. RESULTS: In normal controls, renal P-selectin expression was negative (n = 10). In glomerulonephritis, the up-regulated P-selectin expression on tubular epithelium was significantly higher than that on glomeruli and interstitium (P < 0.01). P-selectin was expressed predominantly on platelets in glomeruli, and glomerular P-selectin expression was more significantly up-regulated in Group II than in Group I or Group III (P < 0.05; and P < 0.01, respectively). There were strong correlations between the degree of tubulointerstitial lesions and the expression of P-selectin on tubular epithelium or within interstitium (rs = 0.395 and rs = 0.337, P < 0.01). Furthermore, P-selectin messenger RNA (mRNA) signals were also detected in the cytoplasm of glomerulus, tubular epithelial cells, interstitium and vascular endothelium. CONCLUSIONS: P-selectin might mediate intraglomerular platelets aggregation, activation and leukocyte accumulation in the early stages of human proliferative glomerulonephritis. The up-regulation of P-selectin in interstitium was associated with interstitial fibrosis and tubular atrophy and may contribute to the progression of glomerulonephritis.

Adult↗
PubMed1996

Variations in the chondroitin sulfate-protein linkage region of aggrecans from bovine nasal and human articular cartilages.

Aggrecan-derived chondroitin sulfate (CS) chains, released by beta-elimination, were derivatized with p-aminobenzoic acid or p-aminophenol; radioiodinated; and subjected to graded or complete degradations by chondroitin ABC lyase to generate linkage region fragments of the basic structure DeltaGlyUA-GalNAc-GlcUA-Gal-Gal-Xyl-R (where DeltaGlyUA represents 4, 5-unsaturated glycuronic acid, and R is the adduct), by chondroitin AC lyase to generate the shorter fragment DeltaGlyUA-Gal-Gal-Xyl-R, or by chondroitin C lyase to generate the same fragment when it was linked to a 6-O-sulfated or unsulfated GalNAc at the nonreducing end. Fragments were separated by size using gel chromatography, by charge using ion-exchange chromatography, and by size/charge using electrophoresis and then characterized by stepwise degradations from the nonreducing end by using mercuric acetate to remove all terminal DeltaGlyUA, by bacterial glycuronidase to remove the same residue when linked to unsulfated or 6-O-sulfated GalNAc/Gal, by mammalian 4-sulfatase to remove sulfate from terminal GalNAc 4-O-sulfate, by chondro-4-sulfatase to remove 4-O-sulfate from other GalNAc/Gal residues, and by beta-galactosidase to remove terminal Gal. Results with CS from bovine nasal cartilage aggrecan show that, in nearly all chains, Xyl and probably also the first Gal are unsubstituted, whereas the second Gal is 4-O-sulfated in one CS chain out of five. The first disaccharide repeat is sulfated at C-4 of GalNAc in one chain out of three and unsulfated in the other two. A sulfated first disaccharide is always joined to an unsulfated GlcUA-Gal-Gal sequence. In contrast, CS from human articular cartilage usually has a sulfated first disaccharide repeat. In CS from young human cartilage, sulfate groups are mostly at C-4 of GalNAc in the major part of the chain, but at C-6 in the nonreducing distal portion. In CS from old cartilage, sulfation at C-6 of GalNAc is a major feature from the nonreducing end down to approximately positions 4 and 5 from the linkage region, where GalNAc 4-O-sulfate is common.

Aggrecans↗
PubMed1996

Unrecognized HIV-1 infection in inner-city hospital emergency department patients.

To determine the prevalence of unrecognized human immunodeficiency virus (HIV)-1 infections in patients presenting to an inner-city hospital emergency department, medical records were reviewed from 1,945 patients diagnosed with diseases not related to HIV or acquired immunodeficiency syndrome. The overall seroprevalence was 2.1% (40): 1.8% (11) in nontrauma versus 3.0% (29) in trauma patients. The highest prevalence was found in black, male, uninsured patients.

Adolescent↗
PubMed1996

Hepatitis A in a Chinese urban population: the spectrum of social and behavioural risk factors.

BACKGROUND: Viral hepatitis is a major public health problem in China. Hepatitis A infections represent a substantial proportion of these, particularly in urban centres. Little is known about the social and behavioural factors in the urban household environment that influence the transmission of hepatitis A. METHODS: We conducted a register-based case-control study to investigate the risk factor patterns for hepatitis A in the general population of the City of Wuhan, in the PR China. Cases were selected from district-based health registers. One control, matched for sex and age, was identified from the case's neighbourhood. Home-based interviews combined with household observation were performed to obtain information on social, behavioural and economic risk factors and the household's indoor and outdoor environment. Analysis included conditional logistic regression. RESULTS: Hepatitis A infection was associated with a variety of social and household-related factors, like handwashing habits (after working in the garden: adjusted odds ratio [OR] = 8.24, 95% confidence interval [CI]: 1.5-44.2, before food preparation: OR = 4.68, 95% CI: 1.8-12.0; before eating: OR = 4.92, 95% CI: 1.5-15.7), and the source of fresh vegetables (OR = 3.90, 95% CI: 1.6-9.8). Hygiene in the kitchen and the household surroundings and the disposal of children's stools in vegetable gardens or refuse pits were significantly associated with univariate analysis only. The lack of possession of luxury consumer items as a surrogate indicator for income was significantly associated with the disease (OR = 2.47, 95% CI: 1.0-6.1). The study clearly established that exposure to health and hygiene education was less in the group of hepatitis A cases when compared to healthy controls (OR = 2.80, 95% CI: 0.9-8.3). CONCLUSION: The results of this study underline how social and behavioural factors are important determinants for hepatitis A in urban Chinese populations. These issues could be addressed by appropriate health and hygiene education targeted at high risk groups, and by strengthening existing procedures for monitoring and control of food hygiene.

Adolescent↗
PubMed1996

Reasons for HIV antibody test refusal in a heterosexual sexually transmitted disease clinic population.

OBJECTIVE: To evaluate acceptance of confidential HIV antibody testing and reasons for test refusal among heterosexual clients of Los Angeles County sexually transmitted disease (STD) clinics. METHODS: From January 1993 through June 1994, all blood specimens routinely collected for syphilis serology were tested blindly for HIV antibody at seven STD clinics. Patients were counseled and offered a confidential HIV test. Rate of refusal of confidential testing and primary reason for test refusal were examined by demographic group and HIV serostatus, as determined in the blinded survey, for all heterosexual clients. RESULTS: Of 20,125 persons offered confidential testing, 35.6% refused the test. Test refusal was higher among men (38.7%) than women [31.1%; adjusted odds ratio (OR), 1.4; 95% confidence interval (CI), 1.3-1.4] and among blacks (38.6%) than whites (28.6%; adjusted OR, 1.7; 95% CI, 1.5-2.0). The most common reason for refusal was 'already know my HIV status' (40.6%), followed by 'don't want to know' (23.9%), and 'not at risk' (19.4%). Confidentiality concerns were cited as the primary reason for refusal by 2.2%. Among the 180 (0.9%) persons who tested positive in the blinded survey, 99 (55.0%) refused the confidential test. Of the 44 seropositive persons who refused the confidential test because they "already knew their HIV status', 29 (65.9%) reported their previous test to be negative. CONCLUSIONS: Efforts are needed to increase acceptance of confidential HIV testing in this heterosexual population and should (1) include a client-centered counseling approach that facilitates accurate self-assessment of risk and addresses the misperception that a prior negative test result implies an absence of risk, and (2) highlight the potential benefits of early intervention medical and psychosocial services.

AIDS-Related Opportunistic Infections↗
PubMed1994

Patterns of uronosyl epimerization and 4-/6-O-sulphation in chondroitin/dermatan sulphate from decorin and biglycan of various bovine tissues.

Dermatan sulphate is a co-polymer of two types of disaccharide repeats: D-glucuronate-N-acetylgalactosamine and L-iduronate-N-acetylgalactosamine. The former can be O-sulphated at C-4 or C-6 of the galactosamine, whereas the latter contains almost exclusively 4-O-sulphated galactosamine. A minor proportion of the L-iduronate may be O-sulphated at C-2. Chondroitin sulphate has no L-iduronate-containing repeats. We have used our recently developed methods for sequence analysis of galactosaminoglycans to investigate the structure of dermatan/chondroitin sulphates of the proteoglycans decorin and biglycan derived from various bovine tissues, like dermis, sclera, tendon, aorta, cartilage and bone. The glycan chains, radioiodinated at the reducing end, were partially cleaved with specific enzymes (chondroitin lyases), and subjected to high-resolution polyacrylamide gel electrophoresis, blotting and autoradiography to identify fragments extending from the labelled reducing end to the point of cleavage. We used chondroitin B lyase to identify the location of L-iduronate, chondroitin AC-I lyase to locate D-glucuronate and chondroitin C lyase to cleave where D-glucuronate residues were succeeded by 6-O-sulphated N-acetylgalactosamine. We could demonstrate tissue-specific, periodic and wave-like patterns of distribution for the two epimeric uronic acids, as well as specific patterns of sulphation in dermatan sulphates derived from either decorin or biglycan. For example, some dermatan sulphates contained D-glucuronate-rich domains that were always 6-sulphated (scleral decorin), others were always 4-sulphated (decorin from bovine dermis, cartilage and bone; biglycan from aorta) or 6-sulphated near the linkage region, but 4-sulphated in more distal domains (decorin from porcine dermis and bovine tendon). Decorin from bone and articular cartilage, as well as biglycan from articular and nasal cartilage, carried largely chondroitin sulphate chains, but also some dermatan sulphate, whereas galactosaminoglycan chains derived from aggrecan of nasal cartilage were free of L-iduronate. Decorin and biglycan from the same tissue (articular cartilage or sclera) had similar glycan chains. The two side chains in a biglycan molecule are probably also similar to one another. The portion of the glycan chains nearest to the core protein was substituted with charged groups to a variable degree, which may correlate with the structural features of the main chain.

Animals↗
PubMed1994

[Changes in the contents of plasma SOD and MDA in 50% III degree burn dogs after delayed fluid replacement].

The plasma SOD and MDA content were determined in 50% III degree burn dogs with delayed fluid replacement. The results showed that the activity of plasma total SOD and CuZn-SOD rapidly declined and were obviously lower during the first 5 days postburn than preburn values, while the content of Mn-SOD did not show significant change. The plasma MDA was evidently elevated in 24 hour but returned to the normal level in 48-72 hours after burn, however it distinctly rose again after 72 hours post-burn. The results suggest that delayed fluid replacement induced generation of free radicals after burn injury, with the result of the occurrence of lipid peroxidation.

Animals↗
PubMed1994

HIV-1 seroprevalence in an inner-city public hospital.

In a hospital-based seroprevalence survey for human immunodeficiency virus type 1 (HIV-1) infection, a stratified sampling method based on age and gender was used to collect 5429 blood samples at an inner-city hospital. Sentinel Hospital Surveillance System (SHSS) criteria developed by the Centers for Disease Control and Prevention were used to classify patient diagnoses into two categories by the likelihood of being associated with HIV-1 infection. The two categories were those with high likelihood of association with HIV-1 (SHSS-ineligible) and those with low likelihood of association with HIV-1 infection (SHSS-eligible). Of the 5429 blood samples, 4262 were SHSS-eligible and 1167 were SHSS-ineligible. After personal identifies were removed, specimens were tested by ELISA and confirmed by Western blot analysis. The overall prevalence rate of HIV-1 infection was 0.98%. The seroprevalence rate was almost 2.6 times higher in high-association patients compared with low-association patients (1.89% versus 0.73%, P < .001). Results from this study indicate a high unsuspected HIV-1 seroprevalence rate in a subpopulation (SHSS-eligible) considered to have diagnoses with low likelihood of association with HIV-1 infection. These patients may better approximate HIV-1 seroprevalence in the general population of the area served by the hospital than would a sample of all patients. Monitoring HIV-1 seroprevalence in the SHSS-eligible group will be a useful measure for community serosurveillance for HIV-1 infection.

Acquired Immunodeficiency Syndrome↗
PubMed1992

A new method for sequence analysis of glycosaminoglycans from heavily substituted proteoglycans reveals non-random positioning of 4- and 6-O-sulphated N-acetylgalactosamine in aggrecan-derived chondroitin sulphate.

We have developed a new procedure for the sequence analysis of glycosaminoglycans, which is particularly suitable for the analysis of chains from heavily substituted proteoglycans. The procedure has been applied to various aggrecan-derived chondroitin sulphates. The glycans are released from the core protein by alkaline scission of the xylose-serine bond, subjected to reductive amination using p-aminobenzoic acid and finally radioiodinated at an acidic pH. Sequence analysis is performed by using various enzymic degradations, partial or complete, followed by high-resolution polyacrylamide gel electrophoresis, blotting and autoradiography to identify segments extending from the labelled reducing end to the point of cleavage. By using chondroitin C lyase to identify the location of 6-O-sulphated hexosamines, we find that chondroitin sulphate from tracheal cartilage has its 6-O-sulphated repeats concentrated to the extreme non-reducing terminal portion of the chain. In chondroitin sulphates derived from intervertebral discs (nucleus pulposus), the 6-O-sulphated repeats have a biphasic distribution; they occur mostly near the linkage region (i.e. the reducing end), but also in the non-reducing portion of the chain. Chondroitin sulphate from nasal cartilage, which is mostly 4-O-sulphated, displays considerable heterogeneity in the linkage region. Three or possibly more charge variants are observed.

4-Aminobenzoic Acid↗
PubMed1991

Threshold of transmission of Brugia malayi by Anopheles sinensis.

In an area of central China where Brugia malayi is transmitted by Anopheles sinensis, three villages were followed for 4 years without any control measures. Diethylcarbamazine (DEC) had been used in a control programme reducing the parasite rate in Shuiwa from 12.72 to 0.59%, in Gubomen from 3.18 to 1.55% and in Moshi from 5.62 to 2.81% (although this fell the following year to 2.23%) up until the start of the trial. The village populations, the human biting rate, the parous and the gonotrophic cycle were comparable for all the areas, yet the microfilariae rate dropped to 0.18% in Shuiwa, 0.31% in Gubomen, but not in Moshi where it increased from 2.23 to 2.43%. This indicated that Shuiwa and Gubomen were below the threshold of transmission. Due to the small number of positive cases remaining, the density measurements showed less change, but a separate study on 44 individuals followed for 6 years revealed that those above 13 microfilariae per 60 mm3 remained unchanged or increased, while those below progressively decreased their densities. The threshold of transmission of B. malayi by An. sinensis was considered to be between 1.55 and 2.23% of the population, providing no individual had a higher density than 12 microfilariae per 60 mm3.

Animals↗