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Biomedical subjects

C G Hayes

Publications and source records attributed to C G Hayes.

At least 73 records · Page 4Linked to original sources
PubMed1989

Isolation of dengue viruses from hospitalized patients in the Philippines, 1983-1986.

Between 1983-1986, 336 strains of dengue virus were isolated from 1,911 patients who had been hospitalized with clinically suspected DF/DHF in Manila and nearby areas. Multiple serotypes were present every year. Although DEN 3 was the most common serotype isolated (40%) over the entire study period, DEN 2 and DEN 1 were more frequently isolated in 1983 and 1984, respectively. DEN 4 was consistently the least common serotype recovered. During 1984, geographic differences in the pattern of serotypes isolated were found for two heavily populated areas located only 70 km apart. A higher proportion of DEN 2 isolates were recovered from patients with gastrointestinal bleeding compared to DEN 1 and DEN 3. A higher proportion of DEN 1 and DEN 3 isolates came from patients experiencing a 1 degree infection compared to DEN 2, and the mean homologous HI antibody titer of the sera that DEN 2 was isolated from was significantly higher than the homologous titers of sera from which DEN 1 and DEN 3 were isolated.

Antigens, Viral↗
PubMed1989

Dengue fever in American military personnel in the Philippines: clinical observations on hospitalized patients during a 1984 epidemic.

From June - August, 1984, 24 American military personnel were hospitalized with dengue (DEN) at Clark Air Base in the Philippines. Their infections were confirmed by serology using the hemagglutination-inhibition test and/or by virus isolation in Aedes pseudoscutellaris cell cultures. Most of the patients had a secondary type of antibody response probably reflecting prior vaccination against yellow fever. Three serotypes of DEN virus were isolated; 7 isolates of DEN 1, 4 isolates of DEN 3 and 3 isolates of DEN 2. All of the patients were Caucasian males between the ages of 20-43 years. All of the cases were clinically diagnosed as classical dengue fever. A platelet count of less than or equal to 100,000/microliters was a common finding (83.3%); however, hemoconcentration was not documented. Other major findings were the occurrence of mild hypotension (62.5%) and petechiae (37.5%). One patient presented with shock and upper gastrointestinal bleeding, but his diagnosis was complicated by a history of epigastric pain and use of aspirin. Although all of the patients fully recovered, the severity of illness was clearly documented by the average-length of hospitalization (5.9 days) and average time absent from work (8.7 days).

Adult↗
PubMed1988

Dengue infections in the Philippines: clinical and virological findings in 517 hospitalized patients.

From May 1983 to January 1984, 517 patients with laboratory confirmed dengue were studied at a hospital in Manila. Secondary dengue infections were diagnosed in 78% of these cases. Peak admission (28%) occurred towards the end of the rainy season in November. Most patients (78%) were less than 15 years old but only 3 were infants. Although some type of hemorrhagic finding occurred in 460 cases (89%), only 110 were classified as dengue hemorrhagic fever and the remainder as dengue fever with hemorrhagic manifestations. The clinical course was usually mild. Gastrointestinal bleeding was present in 65 cases, but only 2 patients developed shock. No fatalities occurred. Dengue 2 was the predominant serotype with 53 isolates, followed by dengue 1 with 48 isolates, dengue 3 with 39 isolates, and dengue 4 with only 8 isolates. Dengue 2 was the only serotype with more isolates from sera with a homologous HI antibody titer greater than 1:20 (57%) than from sera with a homologous HI titer less than or equal to 1:20 (43%). In contrast, most of the dengue 1 isolates (63%) were from sera with a homologous HI antibody titer less than 1:10, and this serotype was strongly associated with primary infections. This study shows that dengue infections remain an important cause of pediatric hospitalization in the Philippines; however, the occurrence of life-threatening dengue hemorrhagic fever as has been described in several other large urban areas of Southeast Asia appears to be rare.

Adolescent↗
PubMed1987

Changing association between community occupational structure and ischaemic heart disease mortality in the United States.

The changing association between community occupational structure and ischaemic heart disease mortality in white men and women of the United States from 1968 to 1982 has been investigated. Occupational structure was represented by the proportion of workers in white-collar jobs. A negative association, with lower mortality in communities with higher levels of white-collar employment, emerged over the period in both men and women. The results for men may be interpreted as suggesting a recapitulation in the US of the changing association between social class and heart disease observed in Britain. Occupational structure, however, reflects resources and opportunities in a community derived from its contribution to the national and international economy. Thus the growing inequalities in heart disease mortality presented in this ecological study relate more appropriately to communities than to individual workers.

Adult↗
PubMed1987

Bites by the Philippine cobra (Naja naja philippinensis): an important cause of death among rice farmers.

We investigated mortality from cobra (Naja naja philippinensis) bite among Filipino rice farmers. Village records in one area were examined and we conducted a careful survey in this and two additional areas among inhabitants at varying risk for snakebite. The death rate from cobra bite was estimated to be as high as 107.1 deaths per 100,000 population per year at one site. Most victims were young (median age 17) and 98% were males. Only 8% of the victims studied reached a hospital. The confirmed death rate averaged 53.8/100,000 for the three populations.

Adolescent↗
PubMed1987

Dengue fever/dengue haemorrhagic fever in Filipino children: clinical experience during the 1983-1984 epidemic.

A total of 377 Filipino children out of a total of 5,427 admissions from October 31, 1983 to March 31, 1984 were found to have dengue fever/dengue haemorrhagic fever The present clinical presentation of these infections was basically similar to that in previous epidemics but hepatomegaly and pleural effusion were less frequent and cardiac involvement, more frequent. The discrepancies between the clinical syndromes and HI antibody responses were evident; thus, the values used for the interpretation of the antibody titers must be reassessed.

Adolescent↗
PubMed1986

Positive response to edrophonium in patients with neurotoxic envenoming by cobras (Naja naja philippinensis). A placebo-controlled study.

To study the ability of anticholinesterase drugs to reverse the potentially fatal paralytic effects of cobra venom, we conducted a placebo-controlled, double-blind crossover trial of intravenous edrophonium (Tensilon) in 10 adults with neurotoxic envenoming caused by bites of the Philippine cobra (Naja naja philippinensis). There was significantly more improvement in ptosis and endurance of upward gaze after edrophonium than after placebo. Five minutes after injection, the mean difference (+/- SD) in the percentage of the iris that was uncovered was 39 +/- 5.47 (70 vs. 31 percent; P less than 0.01), and the mean difference in the number of seconds of upward gaze was 33.1 +/- 9.29 (39.7 vs. 6.6 seconds; P less than 0.01). The expiratory and inspiratory pressures, forced vital capacity, and ability to cough, speak, and swallow also improved after edrophonium. In both the patients who were studied electromyographically, pretreatment and postplacebo responses were typical of myasthenia gravis and became normal after edrophonium. We conclude that anticholinesterases are beneficial in the management of neurotoxic envenoming by Asian cobras (Naja naja), and we recommended a test of edrophonium in any patient with signs of neurotoxic envenoming after snakebite.

Adolescent↗
PubMed1985

Geographic variation in declining ischemic heart disease mortality in the United States, 1968-1978. I. Rates and change, whites aged 35-74 years.

Despite the well known geographic pattern for heart disease mortality, studies of the decline in ischemic heart disease have not provided a comprehensive examination of its spatial component. In this study, the authors computed and mapped mean rates and per cent change in ischemic heart disease mortality for whites aged 35-74 years, for the period of the Eighth Revision (1968-1978) of the International Classification of Diseases. Visual evidence of clustering and markedly different spatial patterns were found for mean rate and per cent change among the state economic areas of the United States.

Adult↗
PubMed1984

Genetic variation for West Nile virus susceptibility in Culex tritaeniorhynchus.

Mutant and geographical strains of Culex tritaeniorhynchus were compared for West Nile (WN) virus susceptibility by feeding on a high-titered blood-virus suspension. Eleven strains also were selected from 2-21 generations for an increase and/or a reduction of oral susceptibility using 90% and 10% infective virus doses, respectively. Only one of the 20 strains tested, e ma, was significantly less susceptible than the control strain. In the selection experiments, none of the strains showed a consistent decrease in susceptibility, but the Changa Manga II (CM) strain showed a sustained increase in susceptibility from generations F11-F21 when selection was discontinued. Reciprocal cross-matings and back-crosses were set up between the selected CM strain and two of the morphological mutant strains, e ma and re e ae, carrying homozygous recessive markers. The resulting progeny were tested for susceptibility to WN virus infection and the ability to replicate virus to high-titers after infection. These results suggest that the trait of increased susceptibility is dominant over resistance. The enhanced ability of infected mosquitoes to replicate WN virus showed partial dominance. Both of these traits appear to be polyfactorial, and are apparently associated with more than one chromosome in Cx. tritaeniorhynchus.

Animals↗
PubMed1982

West Nile virus in Pakistan. 1. Sero-epidemiological studies in Punjab Province.

Serum samples collected during 1978-79 from residents of the Chiniot and Changa Manga National Forest (CMF) areas of Punjab Province, Pakistan, had over-all neutralizing (N) antibody positive rates for West Nile (WN) virus of 32.8% (n = 192) and 38.5% (n = 239), respectively. Comparison of the age-specific antibody rates indicated that the pattern of exposure to infection was different in the two areas. Samples from a 1968 serosurvey of residents of the CMF area had an age-specific N antibody profile similar to the 1978 CMF sample, but both the over-all N and haemagglutination-inhibition (HI) antibody positive rates were much higher in the 1968 sample. When tested against antigen prepared from the Pakistan I-746 strain of WN virus, the percentage of sera HI antibody positive and the geometric mean titre of the sera were significantly higher than when tested against the Egypt-101 antigen. One of 124 and 11 of 50 sera from the 1978 and 1968 samples from CMF exhibited detectable HI antibody against dengue-3 virus, respectively, indicating cross-reacting flavivirus antibody was present. None of the positive sera had a higher titre against dengue-3 than against WN virus, but four of the 1968 sera reacted to equal titre against both antigens. During the 1978-79 CMF survey, serum samples from domestic and wild animals were tested for WN virus antibody. Of the 317 wild birds captured, 85 were N-antibody positive. The only frequently bled mammal was the Indian cow, from which 21 of 58 samples were positive for WN antibody.

Animals↗
PubMed1982

West Nile virus in Pakistan. III. Comparative vector capability of Culex tritaeniorhynchus and eight other species of mosquitoes.

Eight species of mosquitoes from Pakistan were compared with Culex tritaeniorhynchus as experimental vectors of West Nile (WN) virus. When fed by the membrane or cotton-pledget methods on a dose of WN virus 100% infective for Cx tritaeniorhynchus, 95% and 73% of the females of Cx fuscocephala and Cx pseudovishnui became infected, respectively. Cx quinquefasciatus, Cx univittatus, Aedes albopictus, Ae. caspius, Ae. indicus and Ae. lineatopennis were all significantly less susceptible than Cx tritaeniorhynchus. In agreement with the single dose comparisons, the median per os infective dose of WN virus for Cx fuscocephala, Cx pseudovishnui and Ae. caspius was substantially greater than for Cx tritaeniorhynchus. The median parenteral infective dose for all six species tested was less than 1 SMICLD50. Both Cx tritaeniorhynchus and Cx quinquefasciatus were more susceptible to infection with WN virus when fed on viraemic chickens than when fed on defibrinated blood using cotton pledgets or membranes. After infection by intrathoracic inoculation, only Ae. indicus and Ae. lineatopennis showed a reduced ability to transmit WN virus when compared to Cx tritaeniorhynchus.

Animals↗
PubMed1981

Dual infections of Culex tritaeniorhynchus with West Nile virus and Nosema algerae.

Culex tritaeniorhynchus females infected with the microsporidian Nosema algerae, and uninfected control females were compared for susceptibility to infection with West Nile (WN) virus and for the ability to transmit virus. When fed on a high titered dose fo virus, 95% of the control females became infected, whereas only 65% of the N. algerae-infected females were infected with WN virus. However, at two lower viral doses, no differences in susceptibility were observed. No significant differences in transmission ability were found between the N. algerae-infected and control females when tested at 10, 14, and 21 days after infection with WN virus. Also, in mosquitoes dually infected with N. algerae and WN virus, neither agent affected the ability of the other to replicate.

Animals↗