PubMed Health⌕ Search

Biomedical subjects

R B Craven

Publications and source records attributed to R B Craven.

At least 19 recordsLinked to original sources
PubMed1992

Laboratory and field trials of permethrin-treated cotton used as nesting material to control fleas (Insecta: Siphonaptera) on cricetid rodents.

Upholstery cotton treated with four different concentrations (0.25-2.0%) (2,500-20,000 ppm) of an aqueous permethrin solution, used as nesting material by white mice, was laboratory-tested against the potential plague vectors Oropsylla montana (Baker), Thrassis bacchi (Rothschild), and Orchopeas howardi (Baker) and found highly effective (P less than 0.001) for 1 yr. Similarly treated cotton gauze was tested under ambient and 75% RH and was found to be highly effective (P less than 0.001) in both environments for 1 yr. A separate test determined that the LD50 of permethrin-treated cotton was less than 10 ppm. Cotton tested with 0.5% permethrin and distributed under field conditions to cricetid rodents for use as nesting material was found to be highly effective (P less than 0.001 as a pulicide for greater than 4 mo when tested during winter in Larimer County, Colo. Permethrin-treated cotton was less successful in controlling fleas on cricetid rodents during the summer months in a New Mexico hyperendemic plague area.

Animals↗
PubMed1991

Studies on the control of plague in the western United States: laboratory trials of six insecticide dust formulations applied to soil for the control of the plague vector Oropsylla montana (Siphonaptera: Ceratophyllidae).

In this study, six insecticide dust formulations were laboratory-tested in soil mixtures ranging in concentration from 40 to 1,280 parts per million (ppm) against a proven vector of bubonic plague, Oropsylla montana (Baker). Pulicidal effects of the six insecticides, which included three organophosphates, two carbamates, and a pyrethroid, were compared by LD(50) values at both ambient and 75% RH. Permethrin (Pyraperm 455 dust), a pyrethroid with a LD(50) less than 40 ppm, demonstrated the most effective pulicidal action for the 13-wk trial period, followed in order by chlorpyrifos, bendiocarb, propetamphos, diazinon, and carbaryl.

Animals↗
PubMed1991

Plague and tularemia.

Human plague is a local or systemic flea-transmitted infection caused by Yersinia pestis. It is maintained in well established enzootic foci among wild rodents. This article discusses the clinical findings in plague, diagnosis, treatment, and prevention of plague, and management of contacts of human plague cases and of exposures to epizootic plague. Tularemia shares many features with plague but is widespread in animal and arthropod vector populations and essentially throughout the United States.

Animals↗
PubMed1990

Evaluation of the potency and safety of inactivated Japanese encephalitis vaccine in US inhabitants.

In 1981 and 1982, two US citizens died from Japanese encephalitis (JE) acquired in China. In 1983, the Centers for Disease Control initiated an evaluation of a purified, inactivated, mouse-brain-derived JE vaccine produced and used in Japan since 1966. Two doses of this vaccine given 1-2 weeks apart evoked neutralizing antibody titers greater than or equal to 8 in only 77% of recipients. After three JE vaccine doses administered 1-2 weeks apart, 99% developed titers greater than or equal to 8. When a third dose was given to 29 participants 6-12 months after the primary series, all developed titers greater than or equal to 16. Reported adverse reactions included injection site tenderness (18%), erythema (6%), or swelling (3%); headache (9%); and dizziness, fatigue, sleepiness, nausea, chills, fever, or lower back pain (less than or equal to 5%). On the basis of this study, three doses of BIKEN JE vaccine are recommended for US citizens who may be at risk of exposure to JE virus.

Antibodies, Viral↗
PubMed1988

A prospective study of maternal and fetal outcome in acute Lassa fever infection during pregnancy.

Several viral infections have been reported to result in more severe disease in pregnant than non-pregnant women, but the relative risks have not been well characterised. This has now been done for Lassa fever in a prospective study of 68 pregnant and 79 non-pregnant women who were admitted to hospital in Sierra Leone with confirmed Lassa fever. Lassa fever was the main cause of maternal mortality in the hospital, accounting for 25% of maternal deaths. Twelve of 40 patients in the third trimester died, compared with two of 28 in the first two trimesters and 10 of 79 non-pregnant women. The odds ratio for death in the third trimester compared with the first two trimesters was 5.57 (95% confidence intervals 1.02 to 30.26). The condition of the mother improved rapidly after evacuation of the uterus, whether by spontaneous abortion, evacuation of retained products of conception, or normal delivery; 10 of 26 women without uterine evacuation died, but only four of 39 women with evacuation died (p = 0.0016). The odds ratio for death with pregnancy intact was 5.47 (95% confidence interval 1.35 to 22.16). Fetal and neonatal loss was 87%. The risk of death from Lassa fever in the third trimester is significantly higher than that in the first two trimesters and higher than that for non-pregnant women, but evacuation of the uterus can significantly improve the mother's chance of survival.

Acute Disease↗
PubMed1988

Epidemic yellow fever in eastern Nigeria, 1986.

An epidemic of yellow fever occurred in the eastern part of Nigeria during the second half of 1986. Oju, in Benue State, was the most heavily affected region, but yellow fever also occurred in surrounding areas, particularly Ogoja, in Cross River State. In Oju, the mean attack and mortality rates were 4.9% and 2.8%, respectively. Sex and age specific rates were highest in males and in the 20-29 yr age group. The overall case fatality rate was approximately 50%. Diagnosis was confirmed by IgM capture enzyme-linked immunosorbent assay (ELISA) and complement fixation (CF) tests. Entomological investigations implicated Aedes africanus as the epidemic vector. Oju alone probably had about 9800 cases of yellow fever with jaundice, and some 5600 deaths. Outbreaks of this nature could be prevented by inclusion of yellow fever in the Expanded Programme on Immunisation, in areas subject to recurrent epidemics.

Adolescent↗
PubMed1988

Hematologic dysfunction in Lassa fever.

Lassa fever is widespread in West Africa, where the case fatality is about 16% in hospitalized adult patients. The clinical course is highly variable, with a few patients developing severe disease with bleeding, adult respiratory distress syndrome, encephalopathy and hypovolemic shock. We studied 70 patients admitted with suspected Lassa fever to a hospital in Sierra Leone, West Africa. Fourteen patients classified as having severe Lassa fever on the basis of serum aspartate amino transferase (AST) greater than 150 IU/L or viremia of greater than 10(3.6) tissue culture infective dose (TCID) 50/ml were found to have statistically significantly depressed lymphocyte counts when compared with patients with mild Lassa fever (AST less than 150 IU/L or viremia, less than 10(3.6)TCID50/ml), (P less than 0.0001) and with febrile control patients, in whom Lassa infection had been excluded by laboratory criteria (P less than 0.0008). Maximum depression occurred a mean of 10.9 days post onset. Patients with severe Lassa fever also had moderate thrombocytopenia, which was statistically significant when compared with febrile control patients (P less than 0.0003) and this occurred a mean of 10.8 days postonset. The most significant changes were in platelet function, which was markedly depressed in patients with severe Lassa fever (P less than 0.0035 in response to ADP and P = 0.0081 for collagen) when compared with patients with mild Lassa fever, and when compared with febrile controls, (P = 0.0013 for ADP and P less than 0.00001 for collagen). This abnormality was usually maximal on admission to hospital, and probably is an early event, preceding hospitalization in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1988

Importation of Aedes albopictus and other exotic mosquito species into the United States in used tires from Asia.

Between May 18 and December 4, 1986, 79 seagoing containers and their contents of 22,051 used tires were inspected for adult mosquitoes as well as eggs and larvae. Of the total inspected, 5,507 tires (25%) contained significant amounts of water. No adults or eggs were found. Fifteen tires contained mosquito larvae that were identified as Ae. albopictus, Ae. togoi, Culex pipiens complex, Tripteroides bambusa and Uranotaenia bimaculata. The infestation rate for all species was 6.8 infested tires per 10,000 tires (wet and dry) inspected. Aedes albopictus larvae were most frequently collected, occurring at a rate of 20 infested wet tires per 10,000 inspected.

Aedes↗
PubMed1986

Lassa fever. Effective therapy with ribavirin.

In a study of Lassa fever in Sierra Leone, West Africa, we identified two variables associated with a high risk of death, and we evaluated the efficacy of ribavirin and Lassa virus-convalescent plasma for the treatment of Lassa fever. A serum aspartate aminotransferase level greater than or equal to 150 IU per liter at the time of hospital admission was associated with a case-fatality rate of 55 percent (33 of 60). Patients with the same risk factor who were treated for 10 days with intravenous ribavirin, begun within the first 6 days after the onset of fever, had a case-fatality rate of 5 percent (1 of 20) (P = 0.0002 by Fisher's exact test). Patients whose treatment began seven or more days after the onset of fever had a case-fatality rate of 26 percent (11 of 43) (P = 0.01). Viremia with levels greater than or equal to 10(3.6) TCID50 per milliliter on admission was associated with a case-fatality rate of 76 percent (35 of 46). Patients with this risk factor who were treated with intravenous ribavirin within the first six days after onset of fever had a case-fatality rate of 9 percent (1 of 11) (P = 0.006), whereas those treated after seven days or more of illness had a fatality rate of 47 percent (9 of 19) (P = 0.035). Oral ribavirin was also effective in patients at high risk of death. Lassa-convalescent plasma did not significantly reduce mortality in any of the high-risk groups. We conclude that ribavirin is effective in the treatment of Lassa fever and that it should be used at any point in the illness, as well as for postexposure prophylaxis.

Administration, Oral↗
PubMed1979

Development of a statewide program for surveillance and reporting of hospital-acquired infections.

In 1974, a statewide program was begun to improve surveillance of nosocomial infection in Virginia hospitals. Infection control practitioners were trained at the University of Virginia Hospital, Charlottesville, and were encouraged to submit monthly surveillance reports for analysis. In the first three years of the project, 141 students from 65 hospitals within the state attended a two-week basic course, with eight to 10 students per class. Of the 98 Virginia hospitals that sent students, 75 (73%) submitted monthly reports. The consistency of reporting (number of monthly reports received divided by the number of possible reporting months) was 83%. The sensitivity of reported data was estimated in comparative daily prospective surveys to be 69% for participating hospitals, and the specificity was 99%. The crude infection rate for the first 1.1 million patients at risk was 3.3%.

Cross Infection↗
PubMed1978

The Russian flu. Its history and implications for this year's influenza season.

From November 1977 through mid-January 1978 the population younger than 25 years in the Union of Soviet Socialist Republics experienced a widespread epidemic of mild influenza (Russian flu) caused by an H1N1 virus similar to the virus that circulated worldwide during the early 1950s. Outbreaks of Russian flu occurred in school populations and military recruits in the United States starting in mid-January. Many other countries reported outbreaks of H1N1 virus in the winter of 1978. Predictions of influenza activity are always hazardous, but most experts believe that the Russian flu may occur again in the fall and winter of 1978. Other type A and B strains may also circulate; therefore, a trivalent vaccine containing A/USSR, A/Texas, and B/Hong Kong virus strains will be available. It is recommended that the chronically ill and those 65 years and older be the target populations for annual vaccination.

Adolescent↗
PubMed1978

Possible use of frequency-pulse-modulated electron capture gas-liquid chromatography to identify septic and aseptic causes of pleural effusions.

Frequency-pulse-modulated electron capture gas-liquid chromatography was used in conjunction with appropriate derivatization procedures to obtain chromatograms from extracts of pleural effusions. These chromatograms were used to rapidly classify the various types of pleural effusions. With this method we have been able to distinguish among a limited number of effusions caused by congestive heart failure, Mycobacterium tuberculosis, and some other types of bacterial empyemas and pleural effusions.

Chromatography, Gas↗
PubMed1977

Protective efficacy of an inactivated Mycoplasma pneumoniae vaccine.

The protective efficacy of a formalin-inactivated Mycoplasma pneumoniae vaccine was evaluated in a double-blind fashion in 7,861 Marine Corps recruits at Parris Island, South Carolina. Vaccine, administered in a 1-ml dose by a jet-injection device, was glass-grown and contained 264 microgram of protein nitrogen/ml. Phosphate-buffered saline with formalin was injected as a control. Systemic reactions to injection were similar in both groups, but the percentage of vaccinees with erythema (51%) and induration (52%) at 24 hr was significantly greater than the percentage of controls (2%) with these reaction (P less than 0.001). Twenty-one (0.5%) of 3,930 vaccinees and 43 (1.1%) of the 3.931 placebo recipients were hospitalized with pneumonia (chi2=7.61; P less than 0.01). Ten of 21 vaccinees and seven of 43 controls with pneumonia had a positive pharyngeal culture for M. pneumoniae (chi2=1.69; P =0.20), and fourfold rises in titer of serum antibody were noted in five of 14 vaccinees and in 15 of 28 placebo recipients with pneumonia (chi2=7.90; P less 0.0005). Therefore, vaccine efficacy for M. pneumoniae-specific pneumonia was 42% as determined by cultures and 67% by serologic tests. The vaccine showed no protective efficacy for M. pneumoniae-specific bronchitis or for M. pneumoniae pharyngeal carriage in recrutis in training.

Antibodies, Bacterial↗
PubMed1977

Electron capture gas chromatography detection and mass spectrum identification of 3-(2'-ketohexyl)indoline in spinal fluids of patients with tuberculous meningitis.

A basic, extractable, indolic type of compound, which was derivatized with heptafluorobutyric anhydride and pyridine, was obtained from the cerebrospinal fluids of patients with acute tuberculous meningitis. The compound was detected by frequency-pulsed, modulated electron capture gas-liquid chromatography, and it was tentatively identified by mass spectrometry as 3-(2'-ketohexyl)indoline. The compound was found to be valuable for differentiating between tuberculous, cryptococcal, and aseptic meningitides.

Chemical Phenomena↗
PubMed1977

Rapid diagnosis of lymphocytic meningitis by frequency-pulsed electron capture gas-liquid chromatography: differentiation of tuberculous, cryptococcal, and viral meningitis.

Cerebrospinal fluid specimens from patients with tuberculous (17 cases), cryptococcal (15 cases), and viral (14 cases) meningitis were analyzed by frequency-pulsed electron capture gas-liquid chromatography and mass spectrometry. Compounds that disappeared after therapy were found to be present in each of these specimens and were not detected in controls. They occurred in repetitive patterns such that these three types of meningitis could be rapidly distinguished. The compound associated with tuberculous meningitis has been tentatively identified. These finding have implications for rapid diagnosis, pathophysiological studies, and possible new therapeutic approaches.

Chromatography, Gas↗