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Biomedical subjects

T M Vernon

Publications and source records attributed to T M Vernon.

36 records · Page 2Linked to original sources

Epidemic salmonellosis from cheddar cheese: surveillance and prevention.

On August 3, 1976, ongoing Salmonella surveillance in Colorado first detected an epidemic of Salmonella heidelberg infections that eventually totaled 339 isolates. The majority of the cases occurred between July 23 and August 12 in two widely separated cities: Denver and Pueblo. Epidemiologic investigation successively incriminated 1) recent dining at Mexican-style restaurants (p less than 0.001), 2) eating foods containing cheese in these restaurants (p = 0.029), and 3) consumption of cheddar cheese from a single shipment of a single manufacturer (p less than 0.01). The prompt investigation enabled an embargo of 2087 kg (41%) of the contaminated cheese. S. heidelberg was isolated from seven production lots of the incriminated cheese. Surveillance and the epidemiologic investigation may have resulted in prevention of 25,000 diarrheal illnesses.

Adolescent↗

Reporting of gonorrhea by private physicians: a behavioral study.

Physicians in the Denver Metropolitan Area were randomly assigned to study groups and exposed to an intervention designed to test current hypotheses concerning the reasons for underreporting of gonorrhea (lack of saliency in the request, patient interference, violation of the physician-patient relationship, insufficient rewards and excessive administrative cost to the reporter). A periodic telephone contact, initiated by the Health Department and requiring only contact between clerical personnel, more than doubled the number of reported cases. The effect was most striking for those who had not previously reported, and for doctors who practiced alone. An estimate of 42 per cent was obtained for the proportion of cases reported, substantially higher than that produced by retrospective surveys based on recall. The impact of undernotification on total morbidity will vary with the preexisting mix of public and private reporting. The telephone reporting system appears to be an inexpensive and effective program tool for determining that impact locally.

Behavior↗

Tick-borne relapsing fever in Colorado. Historical review and report of cases.

Since 1915 the front range of the Colorado Rocky Mountains has been postulated as a focus of endemic tick-borne relapsing fever. However, the disease has rarely been identified: only two cases have been reported in Colorado since 1944. Three sporadic cases in 1977--tightly grouped geographically and temporally--prompted an epidemiologic review. Tick-borne relapsing fever should be considered in the differential diagnosis of recurrent paroxysmal fever--with or without known presence of ticks--whenever exposure in an endemic area is part of a patient's history.

Adult↗

A waterborne outbreak of gastroenteritis with secondary person-to-person spread. Association with a viral agent.

In December, 1976, an outbreak of gastroenteritis occurred at a resort camp in Colorado. Data obtained by questionnaire from 760 persons indicated that 418 (55%) had had gastroenteritis at the camp or within a week of leaving it, with peak onset within a two-day period. Symptoms included vomiting (81%), diarrhoea (65%), and fever (49%); median duration of illness was twenty-four hours. The attack-rate increased with consumption of water or ice-containing beverages. The camp water supply was found to be inadequately chlorinated and contaminated by a leaking septic tank. Although routine laboratory tests did not reveal bacterial, viral, or parasitic pathogens, immune electron microscopy detected virus-like particles in two of five diarrhoeal stool filtrates. Oral administration of one of these bacteria-free filtrates to two volunteers induced a gastrointestinal illness similar to that observed in the camp visitors.

Camping↗

Raw hamburger: an interstate common source of human salmonellosis.

An interstate common-source outbreak of salmonellosis was first detected in the United States in September and October, 1975, when a tenfold increase in Salmonella newport isolates was noted through routine salmonella surveillance by the Colorado Department of Health. Eighteen primary cases with a distinctive antibiotic resistance pattern (tetracycline, streptomycin, and sulfonamides) were evaluated in a case-control study, and illness was found to be associated with eating raw hamburger (p less than .001) from any store of one grocery chain (p less than .001). A Dallas, Texas, processing plant that supplied the Colorado markets also supplied other states, and these other states were alerted. Maryland discovered nine S. newport isolates with the same antibiogram and, as in the Colorado outbreak, illness was associated with eating raw or very rare ground beef from the same grocery chain (p less than .03). A third outbreak of S. newport with the same antibiogram occurred on a Florida military base. S. newport with the same antibiogram and a phage lysis pattern identical to those of the human epidemic isolates was cultured from frozen hamburger recovered in Colorado and Florida. The associated hamburger originated at the same Dallas, Texas, processing plant. A source of the epidemic strain was not identified, but the organism probably originated before delivery to the plant.

Adolescent↗

Giardiasis in Colorado: an epidemiologic study.

A one-year retrospective laboratory survey in Colorado revealed that 691 (3%) of 22,743 stool examinations for ova and parasites were positive for Giardia lamblia, a higher percentage than that reported from surveys outside of Colorado. The majority of infected residents who were surveyed had experienced an episode of chronic watery diarrhea (median duration 3.8 weeks) with bloating, flatulence, and weight loss (averaging 5.1 kg), and had responded to a course of metronidazole or quinacrine. A statewide telephone survey of 256 cases and matched controls identified: 1) and increased incidence of giardiasis in persons between the ages of 16 and 45, p less than .001, with males and females equally affected; and 2) a higher proportion of cases than controls who visited Colorado mountains (69% vs. 47%), camped out overnight (38% vs. 18%), and drank untreated mountain water (50% vs. 17%), p less than .001. Also identified was a correlation between the seasonal distribution of cases and degree of fecal contamination of mountain streams. These results indicated that G. lamblia is endemic in Colorado and that drinking untreated mountain water is an important cause of endemic ifection.

Adolescent↗

Hepatitis A and B in the family unit. Nonparenteral transmission by asymptomatic children.

Investigation of an outbreak of hepatitis A among members of an adoption organization implicated recently arrived Vietnamese orphans as the source of infection. A serologic study disclosed a 27% prevalence of hepatitis B surface antigen among Vietnamese orphans and a 23.1% (6 of 26) prevalence of hepatitis B antibody among American children of adopting families. Five of the six antibody-positive American children were in families with HBsAg-positive orphans. Thus,healthy orphans from high hepatitis incidence areas may transmit hepatitis B, as well as hepatitis A, in the family unit.

Adolescent↗

An evaluation of three techniques improving immunization levels in elementary schools.

Three techniques for improving immunization levels among school-age children were tested and then compared for most effective use of school nurses' time. Method A involved reviewing school immunization records, specifically inviting immunization-deficient children to a school-based clinic, with some follow-up to achieve good response. Method B involved sending out permission slips for a school-based clinic to all students without additional investment of nursing time. Method C involved a health education program encouraging parents to have their children immunized on their own. Using an average of 38 hours of school nurse time, Method A succeeded significantly better then Method B in immunizing more immunization-deficient children and raising immunization levels , while giving fewer unnecessary immunizations. Method C did not produce significant improvement of immunization levels.

Child↗

Partner notification for human immunodeficiency virus infection in Colorado: results across index case groups and costs.

To evaluate human immunodeficiency virus (HIV) partner notification and referral across index case groups, we analysed results of services provided by the Colorado Department of Health during 1988. Services were offered to 231 index cases; 226 (98%) accepted; 124 (65%) with unsafe behaviours identified 239 partners; 79% of partners were notified; 68% accepted counselling. Seropositivity was 21% in newly tested partners. Index cases chose patient referral for 25% of partners and referred 20% of eligible partners; the provider referred 71%. Index case acceptance of service, proportion of index cases with newly identified HIV positive partners, and choice of partner referral method were similar across groups. Gay men identified fewer partners, had a lower proportion of partners accepting new counselling and testing and referred a lower proportion of partners than heterosexual men. The total costs of the service were $19,496. Twelve new cases of HIV were identified through patient and provider referral and cost per case identified was $1625. Partner notification and provider referral should be offered to all HIV infected individuals in Colorado, as few differences across groups emerged and only 20% of located and eligible partners received counselling through patient referral.

Colorado↗