Surveillance data for waterborne illness detection: an assessment following a massive waterborne outbreak of Cryptosporidium infection.
Proctor ME. Blair KA. Davis JP.
Bureau of Public Health, Wisconsin Division of Health, Madison 53703-3044, USA.
Following the 1993 Milwaukee cryptosporidiosis outbreak, we examined data from eight sources available during the time of the outbreak. Although there was a remarkable temporal correspondence of surveillance peaks, the most timely data involved use of systems in which personnel with existing close ties to public health programmes perceived the importance of providing information despite workload constraints associated with an outbreak. During the investigation, surveillance systems which could be easily linked with laboratory data, were flexible in adding new variables, and which demonstrated low baseline variability were most useful. Geographically fixed nursing home residents served as an ideal population with nonconfounded exposures. Use of surrogate measurements of morbidity can trigger worthwhile public health responses in advance of laboratory-confirmed diagnosis and help reduce total morbidity associated with an outbreak. This report describes the relative strengths and weaknesses of these surveillance methods for community-wide waterborne illness detection and their application in outbreak decision making.
Foodborne outbreaks of hepatitis A in a low endemic country: an emerging problem?
Pebody RG. Leino T. Ruutu P. Kinnunen L. Davidkin I. Nohynek H. Leinikki P.
Department of Infectious Disease Epidemiology, National Public Health Institute, Helsinki, Finland.
This paper describes 2 outbreaks of hepatitis A infection in Finland, a very low endemic area of hepatitis A infection, where a large proportion of the population is now susceptible to infection by hepatitis A virus (HAV). The first outbreak involved people attending several schools and day-care centres; the second employees of several bank branches in a different city. The initial investigation revealed that both were related to food distributed widely from separate central kitchens. Two separate case-control studies implicated imported salad food items as the most likely vehicle of infection. HAV was detected in the stool of cases from both outbreaks using reverse-transcriptase polymerase chain reaction; however, comparison of viral genome sequences proved that the viruses were of different origin and hence the outbreaks, although occurring simultaneously, were not linked. Foodborne outbreaks of HAV may represent an increasing problem in populations not immune to HAV.
Parasitic infections among Southeast Asian labourers in Taiwan: a long-term study.
Department of Parasitology, College of Medicine, Chang-Gung University, Tao-Yuan, Taiwan.
Parasitic infections have been reported to be relatively common among the Southeast Asian labourers in Taiwan. This study, conducted in 1992-6, was designed to determine the temporal changes of the prevalence. Faecal specimens were examined by the formalin-ethyl acetate sedimentation technique and blood samples screened using the quantitative buffy coat technique and confirmed by Giemsa stained blood smear. The overall prevalence of intestinal parasitic infections was 10.3%. The annual prevalence decreased from 33.3% in 1992-3 to 4.6% in 1995-6. The Thai (12.0%) and Indonesian (11.1%) had a higher prevalence than the Malaysian (6.7%) and Filipinos (5.9%). Opisthorchis viverrini was the most important parasite in the Thai and Trichuris trichiura in the remaining groups. Moreover, no blood parasites were found in the labourers. The dramatic temporal decline in the intestinal parasitic infections suggests that limiting the entry of infected persons, periodic follow-ups, and immediate treatment of sporadic cases are necessary in preventing transmission of non-indigenous parasites through large population change.
Acinetobacter bacteremia in patients with diarrhoeal disease.
Iqbal Hossain M. Iqbal Kabir AK. Khan WA. Fuchs GJ.
International Centre for Diarrhoeal Disease Research, Bangladesh, Clinical Sciences Division, Dhaka.
In 1994, 171 (27%) of all positive blood cultures in our hospital were due to Acinetobacter species. Of these, 138 cultures were considered significant, 91 (66%) were community-acquired and 47 (34%) were nosocomial. Most acinetobacter bacteraemia in children < or = 1 year old was community-acquired, while nosocomial infection was more common in children > 1 year old (P = 0.01). Most children < or = 5 years old were severely malnourished. The incidence of bacteraemia was lowest during the post-monsoon to early winter months. Acinetobacter bacteraemia associated mortality was twice (16%) that of all other patients (7.7%, P < 0.0005) and accounted for 4.5% of all hospital deaths during the study period. Bacteraemia caused by Acinetobacter species is an important cause of morbidity and mortality among our patient population with diarrhoeal disease.