Infections in British clinical laboratories, 1982-3.

During 1982-3, 31 specific and 12 uncharacterized infections were reported from 30 of 240 laboratories, representing 29 223 person-years of experience. Thirteen cases of hepatitis included 10 of type B or non-A, non-B hepatitis of probable occupational origin (attributable incidence 34.2 per 100 000 person years) affecting haematology, biochemistry, and postmortem workers. Of nine cases of tuberculosis, three were probably acquired in the laboratory (attributable incidence 10.3 per 100 000 person years) and affected microbiology, morbid anatomy, and postmortem staff. Microbiology staff also acquired, probably from the laboratory, four shigella infections and one each of brucella and herpes. The general community was the probable source of three cases of hepatitis A, two of rubella, and one of varicella. During the two years the risk of laboratory acquired infection mainly concerned the postmortem room and mortuary.     

Discrepant rotavirus results in two laboratories using the same enzyme immunoassay

Rotavirus testing was performed on 66 stool samples in two separate laboratories using the same enzyme immunoassay. Sixteen of 46 of the positive results reported by the reference laboratory were negative in the hospital laboratory. In addition, RNA gel electrophoresis had negative results in the 16 discrepant samples. This indicates the need to repeat or confirm positive results.     

Further studies in the use of monensin in the control of experimental ovine toxoplasmosis

Monensin was fed to 69 pregnant ewes from 81 to 84 days gestation until lambing, at an estimated rate of nil, 16.8 or 27.9 mg per head per day. Ten days after the start of this regime, groups of the ewes were dosed orally with nil, 2000 or 12,000 sporulated Toxoplasma gondii oocysts. Twenty ewes given T. gondii alone (T ewes) produced 29 lambs or aborted foetuses, 16 (55.2 per cent) of which were born dead. The 39 ewes given monensin and T. gondii (M + T ewes) produced 48 lambs or aborted foetuses, 8 (16.7 per cent) of which were born dead. The 10 ewes given monensin alone produced 12 live lambs. No difference of effect was apparent between the two doses of monensin given, nor between the two doses of Toxoplasma oocysts used. Monensin alone caused no discernible problems. Not only were proportionately more live lambs born to M + T ewes than to T ewes, but they were also heavier, possibly due to a lesser "weight" of infection within the gravid uterus. We conclude that monensin fed at about 16 mg per head per day to pregnant ewes can significantly reduce losses at lambing time due to experimentally administered T. gondii.     

Immunosuppression in toxoplasmosis: further studies on mice infected with louping-ill virus

Mice were infected with an avirulent cyst-producing strain of Toxoplasma gondii and given injections of louping-ill virus 7 days later; control mice were given virus but not Toxoplasma. Test and control mice were then killed, in groups, 2, 4, 6, 8 and 10 days later. In the dually infected mice viraemia was later, greater and more prolonged; titres of virus recovered from brain and spleen were greater; production and haemagglutinating antibody to louping-ill virus was later and less, and inflammation in the brain was more severe, than in mice given virus alone. We suggest that T. gondii suppressed the immunity of mice, making them more susceptible to the virus, and that a significant proportion of the increased number of inflammatory cells observed in the brain could have been toxoplasma specific and not virus-specific and hence contributed to the increased susceptibility of the dually infected mice to louping-ill virus.     

Use of the rapid fermentation test in determining carbohydrate reactions of fastidious bacteria in clinical laboratories.

The rapid fermentation test was used to determine the carbohydrate reactions of some of the fastidious bacteria encountered in clinical laboratories, such as: Haemophilus species, including Haemophilus vaginalis; Actinobacillus actinomycetemcomitans; Cardiobacterium hominis; Kingella species; Corynebacterium species; Propionibacterium species; and Erysipelothrix rhusiopathiae. Results were usually obtained within 4 h by using inocula from 24- or 48-h blood or chocolate agar media.