Characterization and ecology of a type A influenzavirus isolated from a sheawater

An influenzavirus isolated from a shearwater bird nesting on Tryon Island on the Australian Great Barrier Reef in 1971 has been more extensively characterized. Haemagglutinin subunits were isolated from the shearwater virus and from the antigenically related avian influenzaviruses A/turkey/Mass./65 (Hav6N2) and A/duck/Penn./69 (Hav6N1). Maps of the tryptic peptides from the heavy polypeptides (HA1) of the haemagglutinin subunits of the three viruses showed a number of differences, but peptide maps of the light polypeptides (HA2) were almost identical, suggesting that these had almost the same amino acid sequence. Extensive tests confirmed that the neuraminidase of the shearwater virus was not related antigenically to any known neuraminidase. The sera collected from pelagic birds nesting on islands in the Capricorn—Bunker group in 1970 were devoid of any antibodies to the shearwater virus, while a high proportion of the sera collected from birds on the same islands in 1972 (one year after the isolation of the shearwater virus) had antibodies to the haemagglutinin and neuraminidase of the shearwater virus, some to a high titre. Thus, the shearwater virus appeared to have only recently been introduced into the area from where it was isolated.     

A new subtype of avian influenzavirus: antigenic characteristics of envelope antigens

The haemagglutination and neuraminidase antigens of three influenza A isolates from ducks in the Ukraine were compared with those of a collection of reference strains of influenza A virus. Duck/Ukraine/1/60 virus contained haemagglutinin related to that of duck/England/56 while its neuraminidase was related to that of turkey/Wisconsin/68 virus and the human A/Hong Kong/1/68 virus. Duck/Ukraine/2/60 and duck/Ukraine/1/63 were themselves closely related. They contained haemagglutinin antigens unrelated to the six haemagglutinin subtypes previously described for avian influenzaviruses and it is suggested that they should be classified as belonging to haemagglutinin subtype Hav7. The neuraminidase antigens of these isolates were antigenically related to those of a number of other avian influenza viruses isolated in England, Canada, and Italy and to that of A/equine/ Miami/63 virus.     

Serological and biochemical analysis of some recent type A foot-and-mouth disease virus isolates from the Middle East

In 1986 and 1987 foot-and-mouth disease virus (FMDV) serotype A was isolated from outbreaks of disease in Saudi Arabia and Iran. Selected virus isolates were antigenically distinct from the prototype A22 virus strain (A22/Iraq/64), but were serologically related to each other. However, polyacrylamide gel electrophoresis showed that whilst the respective Saudi Arabian structural polypeptides were homogeneous, those from an Iran isolate were distinct. Direct sequencing of part of the P-1D (VP1) gene demonstrated considerable difference in nucleotide homology between the two groups of viruses; the Saudi Arabian viruses were closely related to each other but only distantly related to both the A22 prototype virus strain and the Iranian virus isolate. The latter viruses were only slightly more closely related to each other. Thus there appeared to be at least two distinct FMDV type A variants co-circulating in the Middle East, both of which differed considerably from the classical A22 subtype.     

Comparison of the haemagglutinin production of influenza A2 Hong Kong variant and recombinant strains

Seven Hong Kong variant strains were compared for their capacity to produce haemagglutinin (HA). From the results of 9 serial egg passages made at 33°C and 36°C, the A2/Aichi/2/68 strain was found suitable as the vaccine production strain for the 1968-69 monovalent influenza vaccine manufactured in the United States of America.     

Isolation and characterization of influenza A viruses from avian species in Hong Kong.

Surveillance of apparently healthy ducks, chickens, and geese at a poultry dressing plant in Hong Kong yielded 51 haemagglutinating viruses 25 of which were influenza A viruses. Of these, 24 were subtyped into 13 combinations based on haemagglutinin and neuraminidase surface antigens. Of the 13 different influenza A viruses isolated, 7 possessed combinations of haemagglutinin and neuraminidase subunits that have not been reported previously—i.e., Hav2N1, Hav2Nav5, Hav4N2, Hav7N2, Hav7Nav1, Hav7Nav3, and Hav7Nav6. Four of the isolates were non-avid: they were not neutralized by antisera to any of the reference subtypes of influenza A viruses, yet antisera to each isolate inhibited both that virus and a known reference strain. The large number of combinations of haemagglutinin and neuraminidase and the isolation of two different influenza A viruses from one duck suggests that recombination may be occurring in nature.     

A new subtype of type A influenzavirus isolated from turkeys

A new subtype of avian influenzavirus A was isolated in January 1967 from an epizootic in a turkey hatchery in Ontario, Canada. The disease was fatal in 65 of 2 500 hens involved. Virus was isolated from lung and trachea tissue of three dead turkeys. Sera from convalescent birds contained antibody against the viruses isolated from the outbreak but not against other known type A avian influenzaviruses, Newcastle disease virus, Myxovirus Yucaipa, or Mycoplasma gallisepticum.     

Incidence of plasmids in multiply-resistant Salmonella isolates from diarrhoeal patients in Hong Kong from 1973-82

Plasmids present in multiply-resistant salmonella strains including Salmonella typhimurium, S. johannesburg, S. wandsworth, S. derby, S. newport, S. london and S. choleraesuis causing diarrhoea in patients in Queen Mary Hospital in Hong Kong from 1973-82 were studied. In multiply-resistant S. typhimurium, plasmids belonging to groups FIme, H1 or H2 and plasmids encoding trimethoprim-resistance which were compatible with standard plasmids of testable incompatibility groups were detected. In S. johannesburg, both the ASTCKSu- and ASCKSu-resistant strains which were predominant in two consecutive periods of an outbreak were found to harbour the same plasmid which belonged to the incompatibility group FIme. S. wandsworth strains isolated from a hospital outbreak in 1980 harboured an identical R-plasmid belonging to group N. A few strains of the other salmonellae showing resistance to multiple antibiotics were found to harbour R-plasmids belonging to groups H1, H2 and FIme. The only salmonella of the enteric fever group resistant to ampicillin, chloramphenicol and trimethoprim was an S. paratyphi B strain. The resistances were encoded on a plasmid of an unknown incompatibility group. The occurrence and distribution of plasmids in these salmonellae isolated within the 10-year period are discussed.     

Seventy percent of the Mycobacterium tuberculosis isolates in Hong Kong represent the Beijing genotype

We used spoligotyping to study 500 randomly selected pretreatment Mycobacterium tuberculosis (MTB) strains isolated in Hong Kong during the 2 year period 1998-9. It was found that amongst all MTB strains studied, the 'Beijing' genotype strains were highly prevalent in our geographic area, representing about 70% of the isolates. Unlike previous observations in Vietnam, no significant associations were found either between 'Beijing' genotype strains and all other anti-tuberculosis drug resistance phenotypes, or with particular patients' age groups, except for a weak association with isoniazid susceptibility. Eighteen of these strains exhibited spoligotype patterns that were similar but not identical to the 'Beijing' specific pattern. This is the first geographical area where genetic diversity among 'Beijing' genotype of MTB strains has been observed on this scale.     

A surface antigen influenza vaccine. 1. Purification of haemagglutinin and neuraminidase proteins.

Influenza virus was centrifuged in a KII rotor through a sucrose gradient containing Triton N101, a non-ionic surfactant. The micelles of surfactant formed a band in the gradient. As virus particles passed through the surfactant, the haemagglutinin and neuraminidase proteins were stripped from the surface and remained near the surfactant micelles. The residual virus particles sedimented into a denser region of the gradient and were thus separated from the haemagglutinin and neuraminidase antigens. Fractions containing the surface antigens were pooled and Triton was removed by phase-separation at the cloud point.     

Biological and immunological properties of haemagglutinin and neuraminidase expressed from cloned cDNAs in prokaryotic and eukaryotic cells

To study the biological and immunological properties of influenza virus surface glycoproteins, cDNA copies of the haemagglutinin (HA) and the neuraminidase (NA) genes of A/WSN/33 influenza virus were cloned and expressed in prokaryotic and eukaryotic cells. In Escherichia coli, maximum expression of HA is obtained only as a fusion protein in which the NH₂-terminal portion is provided by a bacterial protein (i.e. βgal or trpLE′). The HA expressed in bacteria (bacterial HA) is recognized by polyclonal anti-WSN antibodies but not by neutralizing monoclonal antibodies. The antibodies made against the bacterial HA bind to the detergent-treated viral HA, intact virus and live influenza infected cells, but fail to show either haemagglutination inhibition (HI) or virus neutralization. These results suggest that the three-dimensional structure as well as the antigenic epitopes of the bacterial HA are different from that of native viral HA. HA, expressed from cDNA in cultured animal cells, is shown to possess the structural features of the native viral HA. It is glycosylated, transported to the apical domain of the plasma membrane of polarized cells, causes haemadsorption and can induce cell to cell fusion at low pH after proteolytic cleavage. An attempt was made to define the structural features of HA required for sorting and directional transport by making chimeras with vesicular stomatitis virus G (VSV G) protein either by switching the amino terminus or the carboxy terminus of HA with that of VSV G. These chimeric proteins were translocated across the rough endoplasmic reticulum (RER) but were blocked in transport between the RER and cell membrane. These preliminary results indicate that the three-dimensional structure, in addition to specific sequences, may play a critical role in the transport process. More precise constructions are in progress to delineate the functions of the different domains of HA molecule. HA has been expressed in the lower eukaryote Saccharomyces cerevisiae (baker's yeast). The HA expressed in yeast (yeast-HA) is glycosylated and membrane-bound. It is recognized by both the polyclonal and neutralizing monoclonal antibodies made against the native HA. These results suggest that the yeast-HA retains the antigenic epitopes present in the native viral HA and therefore may be of significance in the development of a subunit vaccine. NA, the other influenza glycoprotein, has been expressed from the cloned cDNA in cultured monkey kidney cells and the expressed NA, like the native viral NA, is glycosylated and enzymatically active. Furthermore, it has been shown that the NH₂-terminus of NA, in addition to providing the anchor function, also provides the signal function for translocation across the rough endoplasmic reticulum (RER). Like HA, NA expressed from cloned cDNA is preferentially transported to the apical domain of the plasma membrane of polarized epithelial cells.     

Serotype distribution and antimicrobial resistance patterns of nasopharyngeal and invasive Streptococcus pneumoniae isolates in Hong Kong children

A study was conducted to determine the vaccine coverage of prevalent carriage and invasive pneumococci from children aged less than 6 years in Hong Kong. A total of 383 nasopharyngeal carriage isolates and 88 invasive isolates from diverse sources were serotyped and their antimicrobial susceptibilities determined. The most common carriage serotypes were the same as the invasive isolates (6B, 14, 19F and 23F), although the rank order of specific serotypes was different. Serotypes in the 7-valent conjugate pneumococcal vaccine (4, 6B, 9V, 14, 18C, 19F and 23F) accounted for 89.7 and 66.1% of the invasive and carriage isolates, respectively. The same seven serotypes comprised 87.5% invasive isolates and 82.8% carriage isolates with resistance to penicillin, erythromycin and/or cefotaxime.     

An estimate of chronic disease burden and some economic consequences among the elderly Hong Kong population.

OBJECTIVES: To estimate the burden of chronic disease for an elderly Chinese population aged 70 years and over, and to illustrate the use of this information in estimating the economic consequences of disease burden using stroke as an example. PARTICIPANTS: A total of 1902 subjects recruited by random sampling of the old age and disability allowance schemes, which cover over 90% of the Hong Kong elderly population, stratified by sex and five year age groups from age 70 years onwards. METHOD: Information was collected on 10 medical conditions at baseline: arthritis, hypertension, cardiac disease, stroke, chronic obstructive airways disease, peptic ulcer, diabetes mellitus, osteoporotic fracture, malignancy, and dementia. A follow up survey was carried out after 18 months to determine the occurrence of new disease and the number with disease who had died. Disease burden is calculated as the number with disease at baseline plus the number developing new disease minus the number who had died. RESULTS: Disease burden figures were highest for arthritis, hypertension, cardiac disease, and peptic ulcer, and were higher in the 70-79 age group than the 80+ age group for some diseases. For stroke, the economic cost based on a population projection for 2001 was estimated to be around HK$1,900,000,000, or US$250 million. CONCLUSION: Information on the burden of chronic disease is important. It enables the economic consequences to be estimated so that strategies can be developed to prevent diseases with high costs and known effective preventive methods.     

Characterization of a novel haemagglutinin subtype (H13) of influenza A viruses from gulls

Influenza A virus strains isolated in the United States of America from ring-billed and Franklin gulls (Larus delawarensis, L. pipixcan) were found to possess a haemagglutinin (HA) antigen distinct from those of the twelve previously designated haemagglutinin subtypes of influenza A virus. Serological assays with antisera to reference strains representing the HA subtypes 1-12 and to a gull isolate, A/gull/Maryland/704/77, showed that the haemagglutinin of the gull virus was not related antigenically to the previously designated subtypes. In addition, comparison of the nucleotide sequences, and deduced amino acid sequences, of the 3′ region of the RNA genes coding for haemagglutinin indicated that the gull viruses represent a genetically distinct group. We propose that this new HA antigen, which has so far been detected only in gulls, be designated H13 and that A/gull/Maryland/704/77 (H13N6) be designated the reference strain for this subtype.     

Strengths and weaknesses of traditional Chinese medicine and Western medicine in the eyes of some Hong Kong Chinese

OBJECTIVE: To explore the attitudes of Hong Kong Chinese towards the strengths and weaknesses of traditional Chinese medicine (TCM) and Western medicine. DESIGN: Qualitative study of subjects' opinions using semi-structured focus group interviews. SETTING: Southern district of Hong Kong Island where many of the residents have a fisherman background. PARTICIPANTS: Twenty nine participants took part in eight focus group interviews. MEASUREMENTS AND MAIN RESULTS: Participants' attitudes towards TCM and Western medicine were explored in the interviews. Both TCM and Western medicine are used concurrently by many people in Hong Kong. Patients make decisions on which type of doctors they want to see for the specific illnesses that they are suffering from. They consider both types of medicines to have strengths and weaknesses: TCM being better in curing the root of the problem but quite slow in action while Western medicine is more powerful but sometimes too powerful with significant side effects. CONCLUSIONS: It is important for medical practitioners to be aware of the health attitudes of their patients from different ethnic backgrounds. It will lead to a better patient-doctor relationship and better compliance of treatment.     

Diversity of influenza A virus subtypes isolated from domestic poultry in Hong Kong.

The second phase of a 2-year influenza virus surveillance programme of domestic avian species in Hong Kong (up to October 1977) yielded influenza A virus, Newcastle disease virus, and Hong Kong paramyxovirus, as well as unidentified haemagglutinating agents. These viruses were isolated from the trachea or cloaca of apparently healthy domestic ducks, geese, and chickens originating from China and Hong Kong. Twenty-five combinations of haemagglutinin and neuraminidase surface antigens were identified from the 136 influenza A viruses isolated. Eight of the combinations do not appear to have been previously reported — Hav3Nav2, Hav4Nav2, Hav4Nav4, Hav4Nav5, Hav4Neq1, Hav6Nav4, Hav6Nav6, and Hav9Nav1. The existence of such a diverse pool of influenza virus genetic information may play a role in the emergence of new human pandemic strains.     

一例H5N1人禽流感病例感染源调查分析

目的 明确1例人禽流感H5N1确诊病例的感染来源.方法 通过现场流行病学调查、密切接触者医学观察、高危从业人员症状监测、实验室检测和溯源调查等方法,判断感染来源.结果 2012年5月17-19日该患儿随母在广州A市场购买活鸭,现场经历屠宰过程.23、24日发病后在当地医院就诊,诊断为呼吸道感染;26日抵香港后诊断为人禽流感病例.23名密切接触者和34名市场禽类销售屠宰从业人员未出现流感样症状.患儿住家附近B市场2名禽类销售人员H9型血清抗体阳性,阳性率为6.06％(2/33).A、B两市场砧板、禽笼等环境标本H5、H9型阳性率分别为9.8％(5/51)和2.0％(1/51).B市场一份砧板H5型阳性标本与患儿标本同属2.3.2.1分支.B市场阳性档口的进货来源与A市场一致.结论 该禽流感病例的感染来源为广州市肉菜市场禽类销售档口.     

Stigma and sex work from the perspective of female sex workers in Hong Kong

While the stigma surrounding sex work is both well documented and easily recognised, few studies examine stigma in this context from the perspective of the sex workers themselves. In this article we report on a study using a modified grounded theory approach to analyse a series of semi-structured interviews with 49 female sex workers in Hong Kong, in order to examine the ways in which this group experiences and negotiates the stigma which arises from their employment in the sex industry. Sex workers in Hong Kong were subject to various stigmatising forces in their daily lives in their interactions with the public, the police and their families. These processes could have a negative impact on the sex workers' health, both through obvious manifestations such as physical or verbal abuse and through more subtle processes such as those which generated or perpetuated vulnerability and those which compelled the sex workers to conceal their identities and withdraw themselves from social networks. These findings are situated in the context of broader research surrounding sex work, drawing attention to the consequences of stigma on health and their interaction with health-service providers, before briefly discussing possible means of overcoming stigma-related barriers to providing adequate healthcare for this marginalised group.     

A case-referent study of cancer of the nasal cavity and sinuses in Hong Kong

A case-referent study of cancer of the nasal cavity and sinuses (NCS) was conducted in Hong Kong where textile and garment manufacturing are major industries. The study population included 225 nasal cavity and sinus cancer cases (NCS), 224 nasopharyngeal cancer (NPC) referents, and 226 all other malignancies (AOM) referents, diagnosed at the Institute of Radiology and Oncology from 1974 through 1981. A strikingly close similarity in occupational distribution between NPC referents and NCS cases was found. Compared to AOM referents, statistically significantly elevated odds ratios of association with nasal cavity and sinuses cancer were found among textile workers (OR, 2.93), fishermen (OR, 3.38), farmers (OR, 1.94) and construction workers (OR, 1.91) particularly for textile workers and fishermen with more than 15 years of employment (textile workers, OR 7.39), (fishermen, OR 3.72). Among textile workers, somewhat more elevated risks were found among weavers (OR, 4.72) after controlling for employment years. Slightly but not statistically significant elevated relative risks of NCS were also associated with those who smoked (OR 1.40) and those who were locally born in Hong Kong (OR 1.53). The known risk of nasopharyngeal cancer among fishermen and those originating from the southern Chinese province of Guangdong was also evident. These findings confirm an association of nasal cavity and sinuses cancer with textile work which has been previously suggested by other studies and provide new leads for further research on the environmental aetiology of cancer of the nasal cavity, sinuses and nasopharynx.     

H5N1禽流感病毒血凝素和神经氨酸酶基因在杆状病毒中的共表达

目的构建共表达H5N1禽流感病毒血凝素(HA)和神经氨酸酶(NA)蛋白的杆状病毒表达系统。方法利用PCR方法分别扩增A/Hubei/1/2010(H5N1)病毒的HA和NA基因,克隆至经改造带有对虾白斑综合病毒(WSSV)早期启动子iel的mpFastBac Dual载体,构建mpFast Bac-HA-NA表达质粒,转化DH10Bac感受态细胞,用获得的Bacmid-HA-NA穿梭质粒转染sf9细胞,获得重组杆状病毒Bac-HA-NA;提取重组杆状病毒Bac-HA-NA的DNA并使用PCR方法检测;利用Western blot检测HA和NA表达,并分别检测重组杆状病毒Bac-HA-NA红细胞凝集能力和神经氨酸酶活性。结果经PCR鉴定,构建的质粒Bacmid-HA-NA正确;Western blot检测表明Bacmid-HANA能在sf9细胞中有效表达HA和NA蛋白,生物活性检测表明Bac-HA-NA能引起红细胞凝集并具有神经氨酸酶活性。结论获得了能同时表达禽流感病毒HA和NA的重组杆状病毒Bac-HA-NA,为进一步研究流感疫苗奠定了基础。