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M E Potter

Publications and source records attributed to M E Potter.

49 records · Page 3Linked to original sources

Selective enrichment broth medium for isolation of Campylobacter jejuni.

A new selective Campylobacter enrichment broth for the isolation of Campylobacter jejuni has been tested with fecal specimens of human, poultry, and bovine origin. We compared the isolation rate with that from the simultaneous direct plating of a duplicate specimen. Of the 380 duplicate specimens examined comparatively, we obtained a 46.3% increase in isolation of C. jejuni by using the new Campylobacter enrichment broth medium.

Animals↗

Pontiac fever: isolation of the etiologic agent (Legionella pneumophilia) and demonstration of its mode of transmission.

Pontiac fever, a unique epidemiologic form of legionellosis, is characterized by a short (one- to two-day) incubation period and a self-limited grippe-like illness without pneumonia. In 1968, the first documented outbreak of this syndrome affected persons who had entered a health department building in Pontiac, Michigan. Epidemiologic analyses clearly implicated as airborne agent and suggested that evaporative condenser water aerosols being disseminated by a defective air conditioning system played a key role in the outbreak. Guinea pigs that were exposed in the building and to laboratory aerosols of evaporative condenser water developed bronchopneumonia. Legionella pneumophilia (serogroup 1) was isolated from the exposed guinea pigs' lungs. Paired acute and convalescent serum specimens from 37 patients were tested by the indirect fluorescent antibody technique using L. pneumophila serogroup 1 antigen, and 31 (84%) had rises in titer from less than 32 to greater than or equal to 64.

Air Conditioning↗

Comparison of selective media for primary isolation of Campylobacter fetus subsp. jejuni.

Three selective media, Skirrow, Butzler, and a modification of Butzler medium, were compared for the primary isolation of Campylobacter fetus subsp. jejuni. This organism was isolated from 87 of 347 specimens (72 from 240 dogs rectal swabs and 15 from 107 cats rectal swabs). The positive rate for dogs (30%) was twice as high as that for cats (14%). Skirrow and Butzler media were comparable in their isolation of C. fetus subsp. jejuni. A significantly higher rate of positive results was obtained with modified Butzler medium. The best combination of two media was that of modified Butzler and Skirrow media, which detected 98% of the isolates obtained. The percentage of Campylobacter-positive specimens was increased by 9% by holding primary isolation plates 72 h.

Animals↗

Airborne spread of brucellosis.

review of epidemic and endemic brucellosis at six abattoirs demonstrates a correlation between case distribution and flow of air from the kill department (stage II) to other areas within an abattoir. Air from the kill department disseminated to nearby departments led to abnormally high brucellosis attack rates for persons who worked in these areas at two abattoirs. Complete physical separation or maintaining negative air pressure in the kill department was associated with reduced risk for workers in other areas at four abattoirs. Cases in persons who had exposure to kill department air but no contact with animal tissues provide strong evidence for airborne transmission of infection. Brucellosis is also contracted through skin contact with infectious animal tissues, but this route of transmission appears less important than formerly believed.

Abattoirs↗

Legionnaires' disease in Kingport, Tennessee.

In August and September 1977 a discrete cluster of 27 serologically or pathologically confirmed cases of Legionnaires' disease, plus six highly presumptive cases were identified in the area of Kingsport, Tennessee. Three patients died. Most patients manifested severe pneumonia and fever; no mild or asymptomatic disease forms were recognized despite intensive case-finding efforts. Illness was epidemiologically associated with residing, visiting, or working in one geographic area of Kingsport, residence there being the factor most strongly associated. Although the attack rate for area residents was 0.64%, the randomly determined prevalence of serologic reactors was 5.2%, which is not significantly different from that in a nonimplicated control neighborhood. The epidemic did not correlate temporally with any identified environmental or demographic event. No source of the bacterium was found either by a detailed case-control study of area associations or by bacterial isolation from sentinel guinea pigs or environmental specimens. There was no evidence of person-to-person spread.

Disease Outbreaks↗

Western equine encephalomyelitis in horses in the Northern Red River Valley, 1975.

In mid-July, 1975, western equine encephalomyelitis (WEE) virus was isolated from mosquitoes collected in flooded areas of eastern North Dakota and western Minnesota. Inasmuch as clinical manifestations of WEE are usually observed in horses before human cases of encephalitis are recognized, surveillance of equine disease was initiated. Sixty-one practicing veterinarians from the are under surveillance reported 281 cases of WEE in horses from June through September, with peak incidence in late July. The high percentage of sero-positive, clinically normal, unvaccinated horses in one region suggested that many horses had developed non-clinical infections. The efficacy of vaccines used by the practitioners appears to have been execllent, as none of the horses vaccinated before the epizootic became ill during the period of surveillance. It was concluded that data collected from routine surveillance of encephalomyelitis in horses could be used to predict epidemics of WEE.

Animals↗

A sausage-associated outbreak of trichinosis in Illinois.

Twenty-three of 50 members of an extended Dutch-German family and their close friends who ate raw homemade summer sausage became ill with trichinosis; 12 patients were hospitalized for an average of 10 days each. The sausage had been made in three different batches according to an old family recipe. One of the batches made from USDA-inspected pork was found to contain Trichinella spiralis larvae by two Illinois State laboratories. The other two batches were negative. Seventeen of the 23 patients submitted information on medical expenses incurred and wages lost because of the outbreak. These costs totaled almost $20,000. There is need for a nationwide program for controlling trichinosis in swine.

Adolescent↗