An enzyme-linked immunosorbent assay-based isolation procedure for verotoxigenic Escherichia coli.

A colony enzyme-linked immunosorbent assay using the hydrophobic grid membrane filter format was developed for the isolation of verotoxigenic Escherichia coli from human and food samples. The method utilizes monoclonal antibodies directed against the verotoxins and is sensitive to all verotoxin 1- and/or 2-producing serotypes. E. coli that produced a minimum of 2 x 10(2) and 2 x 10(3) 50% cytotoxic doses per ml of verotoxins 1 and 2, respectively, were detectable. In a method comparison using human stool specimens, this procedure isolated 29% more E. coli O157 than did the standard sorbitol-MacConkey agar procedure, with no false-positive reactions. When applied to meat, 11 of 20 samples positive for verotoxin by polymyxin extraction yielded verotoxigenic E. coli of a variety of serotypes including O157:H7. Four false positives were noted. This procedure provides a sensitive means for the isolation of verotoxigenic E. coli and should facilitate recovery of those serotypes that are otherwise indistinguishable from nonpathogenic strains.

Effects of acetaminophen on adverse effects of influenza vaccination in health care workers.

OBJECTIVE: To evaluate the effects of acetaminophen on the incidence of adverse effects to, and the immunogenicity of, whole-virus influenza vaccine in health care workers. DESIGN: Prospective, randomized, double-blind placebo-controlled trial. SETTING: Health Sciences Centre, an acute care teaching hospital in Winnipeg. PARTICIPANTS: Of 474 hospital personnel who agreed to undergo influenza vaccination during the 1990-91 season 262 volunteered to participate in the study. INTERVENTIONS: A dose of 0.5 mL of inactivated trivalent whole-virus influenza vaccine was injected into the deltoid muscle. Volunteers were randomly assigned to ingest two capsules of acetaminophen in a half dose (162.5 mg per capsule) or a full dose (325 mg per capsule) or two identical placebo capsules. Capsules were to be taken at vaccination and at 4, 8 and 12 hours afterward. Subjects were asked to answer questions regarding six symptoms in a diary for the 3 days after vaccination and to record their ingestion of the study medication. MAIN OUTCOME MEASURES: Incidence of local (sore arm) and systemic (headache, fever, muscle ache, nausea and diarrhea) side effects as well as serum titres of hemagglutination inhibition (HAI) antibody to vaccine antigens before vaccination and 2 weeks and 6 months afterward. RESULTS: A total of 87, 87 and 88 subjects received the half dose, full dose and placebo respectively; 96% returned the diaries, 83% ingested all four doses of medication, and 87% volunteered all blood samples. Compared with the placebo group the incidence of sore arm was 25% to 28% lower in the half-dose and full-dose groups respectively at 24 hours after vaccination, and the rate of nausea was 90% lower in the full-dose group. The HAI titres were similar among the groups at the three test times. CONCLUSIONS: The full dose of acetaminophen significantly reduced the incidence of sore arm and nausea without affecting the antibody response. Acetaminophen use may increase the acceptance of influenza vaccine by health care workers in whom concern about side effects is an impediment to vaccination.

Cryptosporidium antibodies in manitoba cattle: a pilot study using an indirect fluorescent antibody procedure.

An indirect fluorescent antibody test, using feces-derived oocysts as antigen, was used to detect antibodies to Cryptosporidium spp. in bovine sera in Manitoba. Antibodies were detected in 29 of 50 (58%) sera collected from animals of various ages on farms where calves had laboratory-confirmed cryptosporidiosis and in 76 of 186 (40.9%) sera collected at random from culled breeding stock. Serum antibody, presumably colostral in origin, did not appear to protect young calves from the infection. No geographic preference for the infection was demonstrated.

Infection with Cryptosporidium spp. in humans and cattle in Manitoba.

Between October 1, 1983 and October 31, 1984, fecal specimens from 3656 persons with enteritis and 182 calves, representing 148 herds having a neonatal diarrhea problem, were examined for oocysts of Cryptosporidium spp. Oocysts were found in 1% of human and 25% of bovine specimens. All infected persons were immunocompetent. Children under five years of age had an infection rate of 25/100,000 compared to 1.4/100,000 in older people (p less than 0.005). Rates in northern communities were four to seven times as high as those in southern Manitoba. Human infections occurred most commonly in late summer and fall. In beef calves infection occurred in winter and spring, the calving season in Manitoba. Epidemiological association between the infection in people and in cattle could not be established.

Dirofilariasis presenting as a breast lump.

Dirofilariasis is now recognized as a zoonosis. Infection of humans occurs when a mosquito that has obtained larvae-containing blood from an infected animal transmits the larvae, after they have developed to the infective stage, to a human. Dirofilarial infections in humans have been reported from around the world. In this paper a case is reported in which subcutaneous dirofilariasis in a human presented as a lump in the breast. The epidemiologic and pathogenetic features of this disease are discussed.