American journal of epidemiology.
Publisher:
School of Hygiene and Public Health of Johns Hopkins Univ.. Cary, NC : Oxford University Press
Frequency: Semimonthly
Country: United States
Language: English
Author(s):
Johns Hopkins University. School of Hygiene and Public Health., Society for Epidemiologic Research (U.S.)
Start Year:1965 -
ISSN:
0002-9262 (Print)
1476-6256 (Electronic)
0002-9262 (Linking)
1476-6256 (Electronic)
0002-9262 (Linking)
Impact Factor
5
2022
| NLM ID: | 7910653 |
| (DNLM): | A24180000(s) |
| (OCoLC): | 01480139 |
| Coden: | AJEPAS |
| Classification: | W1 AM451D |
Effect heterogeneity by a matching covariate in matched case-control studies: a method for graphs-based representation. The authors describe a method for assessing and characterizing effect heterogeneity related to a matching covariate in case-control studies, using an example from veterinary medicine. Data are from a case-control study conducted in Texas during 1997-1998 of 498 pairs of horses with colic and their controls. Horses were matched by veterinarian and by month of examination. The number of matched pairs of cases and controls varied by veterinarian. The authors demonstrate that there is effect heterogeneity related to this characteristic (i.e., cluster size of veterinarians) for the association of c...
Case-control study of risk factors associated with isolation of Salmonella saintpaul in hospitalized horses. In an investigation of a 1981-1982 outbreak of nosocomial Salmonella saintpaul infection in hospitalized horses at the University of California Veterinary Medical Teaching Hospital in Davis, California, a case-control study was performed using data gathered from the records of 33 cases and 132 controls. Multiple logistic regression risk analysis was used to identify factors associated with isolation of the organism, controlling for the effects of other, possibly confounding variables. Horses receiving parenteral antibiotics were at 10.9 times greater risk of having S. saintpaul isolated than w...
Marker characteristics of Venezuelan encephalitis virus strains isolated before and after epidemics and equine epizootics in Middle America. Ninety-four strains of Venezuelan encephalitis (VE) virus isolated from sentinel hamsters exposed in the Middle American countries of Mexico, Guatemala, Belize, and Honduras were examined for the presence of virions with marker characteristics of strains that cause large epidemics and equine epizootics. Thirty-four strains came from before and 60 strains came from after the Middle American epidemics and equine epizootics of 1966 and 1969-1972. Twenty-three virion clones that resembled epizootic strains by hydroxylapatite chromatography and Vero monkey kidney cell plaque size determinations wer...
Environmental exposure to Coxiella burnetii: a sero-epidemiologic survey among domestic animals. The prevalence of agglutinating serum antibodies against Coxiella burnetii, the cause of Q fever in humans, was tested in a hospital population of companion animals and livestock in California during 1973--1975. A sample of stray dogs was also tested. Among the hospitalized animals 346 (48%) of 724 dogs, 7 (9%) of 80 cats, 9 (32%) of 28 cattle and 31 (26%) of 121 horses had antibodies against C. burnetii. Of 316 stray dogs 208 (66%) were seropositive. The overall prevalence of 53% among 1040 dogs tested was comparable to the 63% antibody prevalence found in an earlier survey among coyotes and ...
Eastern equine encephalitis in Massachusetts, 1957-1976. A prospective study centered upon analyses of mosquitoes. Reappearance of eastern equine encephalitis (EEE) in Massachusetts residents in the 1970's provided an opportunity to assess the predictive value of data on rainfall, EEE in horses, and carriage of EEE virus (EEEV) by mosquitoes, factors which had been studied annually since the last EEE outbreak in 1955-1956. The cycle of multiple cases during 1973-1975 started in a second consecutive year of rainfall that exceeded the annual mean by more than 20 cm, conditions recapitulating the 1955-1956 experience. In 1973, widespread EEE fatalities in horses presaged human cases, another recapitulation of...
Search for persistent epizootic Venezuelan encephalitis virus in Guatemala, El Salvador and Nicaragua during 1970-1975. Evidence was sought during 1970-1975 of persistence of equine-virulent Venezuelan encephalitis (VE) virus in regions of Central America that were heavily involved in the epidemic-equine epizootic of 1969. (a) Four sentinel horses were exposed in an arid, upland region of the Atlantic drainage of Guatemala during August-October 1970, but no horse became infected. (b) The epicenter region of the 1969 outbreak, in southwestern Guatemala and southwestern El Salvador, was studied during July 1970-February 1974; no antibody developed in sentinel horses, sentinel hamsters did not die, mosquitoes yiel...
Search for epizootic-like Venezuelan encephalitis virus at enzootic habitats in Guatemala during 1969-1971. Seventy-four strains of Venezuelan encephalitis (VE) virus recovered from sentinel hamsters or mosquitoes at enzootic habitats in Guatemala in the two years following the 1969 epidemic-equine epizootic were examined for ability to produce small plaques in Vero African green monkey kidney cell cultures, like isolates obtained during the epizootic. (a) One strain recovered from a sentinel hamster in late October 1969 at an enzootic habitat near the epicenter of the hemagglutination-inhibition (HI) and equine-virulence properties like epizootic virus; this strain retained its small plaque charact...
Comparative analyses of members of the Venezuelan equine encephalomyelitis virus complex. Polyacrylamide gel electrophoretic examination of viruses selected from the Venezuelan equine encephalomyelitis (VEE) complex revealed distinct strain to strain differences in profiles of the two virion envelope proteins. The core protein was identical in all viruses tested. We detected five electrophoretic patterns into which the virus strains could be classified and these were designated alpha (alpha), beta (beta), gamma (gamma), delta (delta), and episolon (episolon). Isolates representing variant E of subtype I exhibited a profile characterized by only one apparent envelope band. The epizo...
Epidemic Venezuelan equine encephalitis in North America in 1971: vector studies. A major epidemic of Venezuelan equine encephalitis occurred in south Texas in the summer of 1971. More than 1500 equines died of VEE in Texas, and 110 human cases with no deaths were reported. Vector studies in south Texas and northern Tamaulipas revealed that the overall mosquito infection rates during the peak of the epidemic were about 1:100, one of the highest rates observed for a major epidemic. Mosquito infection rates of this magnitude could easily explain the intensity of VEE outbreaks in both equines and man. A total of 943 VEE virus isolations were made from mosquitoes. Eight of the ...
Arbovirus vector ecology studies in Mexico during the 1972 Venezuelan equine encephalitis outbreak. Virus vector studies were conducted in the States of Durango, Chihuahua, and Tamaulipas, Mexico, in June and July 1972. Apparently only a low level of Venzuelan equine encephalitis (VEE) virus transmission to equines occured at the time of the study, and the infection was restricted to areas which had not experienced overt activity during the preceding year. The low level of infection was associated with a scarcity of mosquitoes. The IB (epidemic) strain of VEE virus was isolated from two pools of Anopheles pseudopunctipennis (Theo.) and the blood of one symptomatic equine. The low mosquito po...
Epidemic Venezuelan equine encephalitis in North America in 1971: vertebrate field studies. Epidemic Venezuelan equine encephalitis in North America in 1971: vertebrate field studies. Am J Epidemiol 101:36-50, 1975.-In June 1971, epidemic Venezuelan equine encephalitis (VEE) invaded the lower Rio Grande Valley in south Texas. The Boca Chica area of Cameron County was selected as a study site to investigate vertebrate involvement in the natural cycle of epidemic VEE on the basis of considerable evidence of VEE virus activity there in equines, humans, and mosquito vectors. Only one VEE virus isolation was made from 4739 wild and domestic non-equine vertebrates, although numerous equine...
Experimental infection of horses with three strains of Venezuelan equine encephalomyelitis virus. I. Clinical and virological studies. Henderson, B. E., W. A. Chappell, J. G. Johnston, Jr. and W. D. Sudia (CDC, Atlanta, Ga. 30333). Experimental Infection of horses with three strains of Venezuelan equine encephalomyelitis virus. I. Clinical and virological studies. Amer J Epidem 93: 194–205, 1971.—Clinical effect, viremias and antibody responses were compared in horses inoculated with the following strains of Venezuelan equine encephalomyelitis (VEE) virus: Fe3-7C, isolated from Culex (Melano-conion) spp. mosquitoes collected In 1963 in the Florida Everglades; TC-83, the Fort Detrick live, attenuated vaccine strain; and GJ...