The COVANOS trial - insight into post-COVID olfactory dysfunction and the role of smell training.

BACKGROUND: Olfactory dysfunction is a cardinal symptom of COVID-19 infection, however, studies assessing long-term olfactory dysfunction are limited and no randomised-controlled trials (RCTs) of early olfactory training have been conducted. METHODOLOGY: We conducted a prospective, multi-centre study consisting of baseline psychophysical measurements of smell and taste function. Eligible participants were further recruited into a 12-week RCT of olfactory training versus control (safety information). Patient-reported outcomes were measured using an electronic survey and BSIT at baseline and 12 weeks. An additional 1-year follow-up was open to all participants. RESULTS: 218 individuals with a sudden loss of sense of smell of at least 4-weeks were recruited. Psychophysical smell loss was observed in only 32.1%; 63 participants were recruited into the RCT. The absolute difference in BSIT improvement after 12 weeks was 0.45 higher in the intervention arm. 76 participants completed 1-year follow-up; 10/19 (52.6%) of participants with an abnormal baseline BSIT test scored below the normal threshold at 1-year, and 24/29 (82.8%) had persistent parosmia. CONCLUSIONS: Early olfactory training may be helpful, although our findings are inconclusive. Notably, a number of individuals who completed the 1-year assessment had persistent smell loss and parosmia at 1-year. As such, both should be considered important entities of long-Covid and further studies to improve management are highly warranted.

Chlamydiosis in workers at a duck farm and processing plant.

An outbreak of chlamydiosis was investigated in workers at a duck farm and processing plant during winter 1989. Chlamydia psittaci was isolated from ducks, but there was little evidence of clinical chlamydiosis in the ducks. Serological tests showed that 76% of workers had been exposed to infection, 12% recently, 16% had not been exposed and 8% had inconclusive test results. There was a strong association (P < 0.05) between years of employment and exposure to infection. Infection appeared to be contracted during the first year of employment. Measures were implemented to reduce shed contamination and control rodents and wild birds. At the same time, ducks were medicated, the processing plant was modified, work practices were altered and workers were advised about chlamydiosis to reduce the risk of human infection.

The effects of subacute and chronic exposure to 4-aminopyridine on reproduction in coturnix quail.

When male and female coturnix quail (Coturnix coturnix) were given a single subacute oral dose (5.62 mg/kg) of the avian frightening agent 4-aminopyridine (4AP) and paired with untreated mates, there was no effect on the reproductive performance of males; egg production of females was reduced the third week after treatment but recovered during the fourth week. Chronic exposure to 31.6, 100, and 316 ppm of 4AP in the diet of mated pairs did not affect reproductive performance during or after the 4- or 6-week period the chemical was fed, but no birds fed 1,000 ppm produced live chicks after treatment began and all died within 3 weeks. The 28-day LC50 of 4AP was determined to be 447 ppm for male coturnix and 562 ppm for females. F1 progeny from quail fed 31.6, 100, and 316 ppm 4AP and randomly mated at maturity showed no reproductive effects from their parents' exposure.

The chronic toxicity of methiocarb to grackles, doves, and quail and reproductive effect in quail.

Methiocarb (4-methylthio-3, 5-xylyl N-methyl carbamate, Mesurol, Bay (3744), a bird repellent, was fed in concentrations of 100 to 1,000 ppm to common grackles (Quiscalus quiscula), mourning doves (Zenaida macroura), and breeding pairs of coturnix quail (Coturnix coturnix) to investigate the possibility of cumulative intoxication. Although aversion to treated diets was readily apparent in most of the tests, the 28- to 30-day median lethal concentration (LC50) was determined to be greater than 100 ppm for grackles, 630 ppm (95% confidence limits, 480-830 ppm) for doves, and greater than 1,000 ppm for coturnix quail. Methiocarb appeared to be noncumulative when measured by an index of chronicity: birds consumed several LD50 doses during a day's feeding, and when deaths occurred, they appeared to be due to acute intoxication. Egg production and live chick production were not affected in coturnix fed 100 ppm but were reduced at 316 and 1,000 ppm.