The seroprevalence of hepatitis B, C and D markers was assessed in a sample of 670 Albanian refugees in Southern Italy in 1997. The mean age was 25 years (S.D. = 12·3). Of study subjects 62·1% (95% CI: 58·4–65·7) were positive for anti-HBc antibodies and 13·6% (95% CI: 10·9–16·1) for HBsAg. The prevalence of anti-HBs was 47·6% (95% CI: 43·8–51·3). Among HBsAg carriers the prevalence of HBeAg was 7·7% (95% CI: 2·2–13·1). The highest carrier rate for HBsAg (25·5%; 95% CI: 16·7–34·3) was found in the age group 21–25 years. A relevant finding was a prevalence of HBsAg of 8·1% in children 10 years and under. The prevalence of anti-HCV antibodies was 0·3% (95% CI: 0·0–0·7) while only one of the HBsAg carriers was positive for anti-HDV (1·1%, 95% CI: 0–3·2). In Albania, hepatitis B infection represents a public health priority that should be addressed by a universal vaccination campaign.

The influence of cytomegalovirus (CMV) infection as a co-factor in HIV-1 disease progression has mainly been studied in haemophiliacs and remains controversial. Based on the files of 1683 HIV-1-infected patients in the Seropositive Cohort (SEROCO) and Haemophiliacs Cohort (HEMOCO) cohorts, we studied the role of CMV infection in progression to CD4+ cell counts of less than 200 μl, AIDS onset and death, in various HIV exposure groups. Adjusted relative risk (aRR) of progression to AIDS and to death was respectively 1·30 (P = 0·05) and 1·58 (P = 0·007). In the sexual exposure group the influence of CMV infection on the risk of progression to AIDS was of borderline significance (aRR = 1·50; P = 0·07) and was more marked on the risk of death (aRR = 2·00; P = 0·03). No such influence of CMV infection was observed in the transfusion and intravenous drug use exposure groups. When we studied the influence of CMV infection according to the stage of HIV disease, the main effect was on progression from AIDS to death, probably because CMV disease is a late event. Sexual CMV transmission and frequent re-exposure to CMV may explain why CMV infection emerged as an important co-factor for HIV progression only in the sexual exposure group.

To evaluate whether or not human herpesvirus 8 (HHV8) can be transmitted through a non-sexual route a serological survey was carried out in a group of 51 catholic nuns. The seroprevalence rate and the geometrical mean antibody titre to anti-latent HHV8 antigen were similar in nuns and in a group of 60 women, matched by age, in the general population (27 vs. 24%; 1028 vs. 1575, respectively). Moreover, by using nested polymerase chain reaction (PCR), HHV8 DNA sequences were detected in 7 of 16 (43·8%) saliva and peripheral blood mononuclear cells (PBMC) from patients with classical Kaposi's sarcoma (KS) and in 3 out of 7 (42%) AIDS-KS patients. None of 5 HIV positive persons who did not have KS tested positive for HHV8 DNA. HHV8 DNA sequences were also detected in 2 of 12 (17%) saliva and 1 PBMC sample out of 12 healthy HHV8 positive individuals (age range: 30–80 years old). This paper suggests that non-sexual transmission of HHV8 is operating in our geographical setting and saliva may be a potential source of HHV8 spreading in the general population.

Hepatitis B Virus (HBV) e antigen (HBeAg), HBV DNA and precore mutations affecting HBeAg expression during active replication were studied in 72 Tunisian hepatitis B surface antigen (HBsAg) positive individuals: 30 asymptomatic carriers of the virus, 37 with chronic hepatitis and 5 with acute hepatitis. HBV DNA was detected in 44 patients, but only 20% of them expressed HBeAg. Precore mutant strains, with mutations at position 1896 or at positions 1896 and 1899, were detected by PCR-hybridization in 86 and 36% of patients, respectively. Wild-type strains were detected in 54% of patients. Precore mutants were found in chronically and in acutely infected individuals, in patients with severe and asymptomatic infections, in HBeAg positive as well as HBeAg negative individuals. These results show the high frequency of HBV precore mutants in Tunisia.

Over a 14-year period (1984–97) the presence of rotavirus in stool samples from children under 15 years with acute gastroenteritis was studied by enzymoimmunoanalysis. Serotyping (G1–G4) was performed using monoclonal antibodies. A total of 17348 children under 15 were investigated. Rotavirus was detected in 3637 (21·0%) specimens, 74·6% of which were from children younger than 2 years old. G1 and G4 were the most frequent serotypes. In 1991–7, the minimum incidence of rotavirus gastroenteritis in children under 4 years of age was 21·7 cases/1000 children/year. By the age of 5 years, at least 1 out of 11·3 children and probably 1 out of every 5–6 children in this area had experienced an episode of rotavirus gastroenteritis that required medical care. In the 1984–90 period a clear seasonality was not observed but in the second period of the study (1991–7), seasonality was marked, with peak activity in winter.

Eperythrozoon is an obligate parasitic bacteria found in many species of animals. A large scale investigation of the prevalence of Eperythrozoon spp. in humans, was conducted in a developing country using light, electron microscope and animal inoculation. Samples were collected in undeveloped areas of Inner Mongolia in China over a 2-year period of 1994–6. Of the 1529 investigated samples, 35·3% were found to be Eperythrozoon spp. positive. The prevalence of infection was associated with occupation and seasonal variations. The infections were mainly mild, in 89·6% of cases (excluding pregnant women and their children). Of 74 pregnant women tested in the areas of high prevalence, 44 were confirmed Eperythrozoon spp. positive. Similarly, eperythrozoa were found in all 44 umbilical cords tested and in the neonatal peripheral blood samples taken at birth. These data suggest that eperythrozoa can be transmitted via the placenta.

Lung and intestine of 49 pigs with respiratory diseases and endocervical swabs from 205 sows with reproductive disorders were investigated for chlamydial infection by polymerase chain reaction. PCR primers targeted DNA sequences on the chlamydial omp1 or omp2 genes. PCR amplicons were generated from 49·0% of pigs with respiratory disease, from 60·0% of sows with reproductive disorders, from 24·5% of respiratory healthy controls, but from no endocervical swabs from fertile sows. By DNA hybridization, a high prevalence of mixed infections with Chlamydophila abortus and Chlamydia suis in the porcine lung and intestine was found and confirmed by RFLP and nucleotide analysis. Of the omp1-PCR amplicons from endocervical swabs 81·3% were identified as Chlamydophila abortus, indicating an association of this chlamydial species with reproductive disorders in sows. Nucleotide sequence analysis of omp1-amplicons identified as deriving from Chlamydia suis shared a maximum of 82·7% homology with the reference strain S45.

Human rabies is known to be endemic in countries bordering Lebanon, but its prevalence in Lebanon has not been studied before. All eight cases of human rabies reported to the Lebanese Ministry of Public Health between 1991 and 1999 were reviewed, as well as three other cases admitted to the American University of Beirut Medical Center. A total of 1102 cases of animal bites to humans, the majority of which were dog bites, were reported to the Ministry of Public Health between 1991 and 1996. In this period, 2487 doses of rabies vaccine were administered to the above group, as post-exposure prophylaxis. Veterinarians, a high risk and educated group, were interviewed, and only 7 out of 72 were found to have been vaccinated. Major improvements in surveillance and reporting, better control of animal rabies, more awareness especially among high risk groups, and regional cooperation, are all needed to prevent and control this deadly infection.

In this study the impact of pregnancy duration on the measured level of HSV-2 antibodies was assessed. The study population comprised 35940 pregnant women in Norway, in 1992–4, followed during pregnancy. A random sample of 960 women was selected. A mean of 2·6 serum samples from each woman were analysed for HSV-2 specific IgG antibodies at different times in pregnancy. Crude and adjusted odds ratios were estimated in logistic regression models taking all observations per women into account. Twenty-seven percent of the pregnant women had antibodies against HSV-2 in the first trimester. The adjusted odds ratio of being HSV-2 antibody positive decreased during the pregnancy and was 0·5 (0·2–0·9, 95% confidence interval) in the 40th as compared to the 10th week of pregnancy. About 50% of initially HSV-2 positive women did not have detecable antibodies by the end of the pregnancy. This may be explained by haemodilution during pregnancy. Our findings have diagnostic implications and should encourage further studies.

This is a long-term study that investigates the dynamics of a population of Rattus norvegicus (Berk) inhabiting a sewerage system in London. Thirteen years (1986/7–1998/9) of data from sewer baiting records were analysed (a total of 35478 records). Manholes were baited with the anticoagulant Brodifacoum (0·005%) on a pinhead oatmeal bait base. Time series analysis was conducted on the data set to determine the underlying trend of the data and the population fluctuations about this trend. An exponential curve was found to give an accurate and realistic fit to the data and indicated that the rat population had decreased over the study period. Decomposition analysis indicated a 5-year cycle best described fluctuations around this trend.

A St. Louis encephalitis (SLE) epidemic in Florida during 25 weeks in 1990–1, resulted in 222 laboratory-diagnosed cases, an attack rate in the 28 affected counties of 2·25/100000. Disease risk rose with advanced age, to 17·14/100000 in persons over 80 years, and all 14 fatal cases were in persons over 55 years (median, 70 years). Community serosurveys in Indian River County, the epicenter of the outbreak (attack rate 21/100000), showed acute asymptomatic infections in 3·6% of the persons surveyed, with higher rates in persons with outdoor occupational exposure (7·4%) and in clients of a shelter for the indigent (13·3%). A matched case-control study found that evening outdoor exposure for more than 2 h was associated with an increased risk for acquiring illness (odds ratio [OR] 4·33, 95% CI 1·23–15·21) while a number of recommended personal protective measures were protective. Four SLE patients were dually infected with Highlands J virus, the first reported cases of acute infection with this alphavirus. The case-control study provided the first evidence that a public education campaign to reduce exposure had a protective effect against acquiring the disease.

Most outbreaks of viral hepatitis in India are caused by hepatitis E. This report describes an outbreak of hepatitis B in a rural population in Haryana state in 1997. At least 54 cases of jaundice occurred in Dhottar village (population 3096) during a period of 8 months; 18 (33·3%) of them died. Virtually all fatal cases were adults and tested positive for HBsAg (other markers not done). About 88% (21/24) of surviving cases had acute or persistent HBV/HCV infections; 54% (13/24) had acute hepatitis B. Many other villages reported sporadic cases and deaths. Data were pooled from these villages for analysis of risk factors. Acute hepatitis B cases had received injections before illness more frequently (11/19) than those found negative for acute or persistent HBV/HCV infections (3/17) (P = 0·01). Although a few cases had other risk factors, these were equally prevalent in two groups. The results linked the outbreak to the use of unnecessary therapeutic injections.

Samples from 2427 cattle, 661 goats, 104 sheep, 98 camels and 82 horses were screened for brucella infections by the Rose Bengal Test and positive reactors confirmed by the complement fixation test. In cattle, the highest individual seroprevalence was in dairy herds kept under the intensive husbandry system, with an individual prevalence of 8·2% and unit (herd) seroprevalence of 35·9%. This was followed by the pastoral husbandry system in the Western Lowlands with 5·0% individual but a higher unit (vaccination site) prevalence of 46·1%. The lowest was in the mixed crop-livestock system in the Southern Highlands with individual 0·3% and unit (village) prevalence of 2·4%. In sheep and goats, no positive animals were detected in the mixed crop-livestock areas. In the Eastern Lowlands individual prevalences of 3·8% (goats) and 1·4% (sheep) and unit prevalence of 33·3% (goats) and 16·7% were found, while 14·3% of individual goats and 56·3% of the units in the Western Lowlands were positive. No positive horses were found. The present study documents the first serological evidence of Brucella spp. infection in camels (3·1%) in Eritrea.

The aim of this study was to estimate the prevalence of hepatitis B exposure in the population of the Republic of Ireland, by measuring the prevalence of hepatitis B anti-core antibody in oral fluid collected by postal survey.

A random multi-stage stratified sample of Irish households was obtained, using the Irish electoral register as the sampling frame. A total of 962 households were selected, and a household response rate of 60·4% was achieved. Oral fluid specimens totalling 1714 were tested for antibody to hepatitis B core antigen (anti-HBc), using an Immune Capture Enzyme Immuno-Assay. Five specimens (0·29%) were found to contain anti-HBc. Adjusting for study design, the estimated anti-HBc prevalence in the Republic of Ireland is 0·51%.

This study demonstrates that self-collection of oral fluid samples is acceptable to the public, and based upon the data generated, that the Republic of Ireland has a low prevalence of hepatitis B infection.

Surveillance of dengue fever is mainly based on specific laboratory tests. However non-specific systems, such as clinical surveillance, are also required. In French Guiana, we have tested a non-specific laboratory surveillance system where different biological examinations performed for other reasons than the diagnosis of dengue fever were analysed as methods for dengue fever surveillance. The number of negative malaria diagnoses in Cayenne and Kourou was found to be the best indicator of dengue fever infections in these towns. This surveillance system appears to be very simple and reliable, and a test which could serve as an indicator that is likely to be found everywhere.

Dengue fever (DF) or dengue haemorrhagic fever (DHF) has not previously been reported in Coimbatore and Erode districts in Tamil Nadu in India. In 1998, 20 hospitalized cases of fever tested positive for dengue virus IgM and/or IgG antibodies. All of them had dengue-compatible illness, and at least four had DHF. Two of them died. Sixteen cases were below 10 years of age. The cases were scattered in 15 distantly located villages and 5 urban localities that had a high Aedes aegypti population. Although the incidence of dengue-like illness has not increased recently, almost 89% (95/107) of samples from healthy persons in the community tested positive for dengue IgG antibodies. The study showed that dengue has been endemic in the area, but was not suspected earlier. A strong laboratory-based surveillance system is essential to monitor and control DF/DHF.

EEC directive 76/160 requires member states to apply microbiological and chemico-physical standards for the quality of recreational waters. In observation of this regulation, in the present study 144 samples of seawater were taken over a 12-month period and tested to determine viral contamination. The samples were collected from the coastal waters of the Italian town of Pesaro, which is located on the Adriatic Sea. Using cell culture techniques, 32·6% of the seawater samples were found to be contaminated with enteroviruses. Isolation of these viruses was most frequent in the summer months. Thus, our results indicate the need to increase the frequency of monitoring of these waters and to eliminate the sources of contamination.

The prevalence and genetic diversity of hepatitis C infection in women attending antenatal clinics in two regions of England was investigated to inform future surveillance and control measures. Women booking into antenatal care are routinely offered a test for immunity to rubella. Serum residues from these tests were unlinked, anonymized and archived as part of the Unlinked Anonymous Prevalence Monitoring Programme (UAPMP). The serum specimens were tested for anti-HCV using a cost-effective pooling strategy. After taking into account differential sampling from the UAPMP serum archive, the adjusted overall prevalence of anti-HCV was 0·43% (95% CI: 0·32–0·53) in London and 0·21% (95% CI: 0·14–0·28) in the Northern and Yorkshire region. Restriction fragment length polymorphism of amplified HCV RNA identified type 3a as the most common HCV genotype in these antenatal women. The prevalence of anti-HCV in antenatal women in the UK is low and consistent with that expected from injecting drug use.

The fact that a substantial proportion of tuberculosis drug resistance (especially multidrug resistance) is due to transmission of resistant strains or treatment failure in the UK underlines the need to strengthen control in this country. Early identification and effective treatment of cases (including measures to support adherence and appropriate use of initial treatment regimes involving at least four drugs in those at risk of isoniazid resistance) would help to control the problem [1].

Cryptosporidiosis is the most common cause of outbreaks of disease linked to mains water supply in the United Kingdom and the second commonest in the United States. Recent evidence has suggested that prior population immunity may have an impact on the epidemiology of waterborne outbreaks and in particular prior immunity may reduce the power of case-control studies for demonstrating association between disease and water consumption behaviour. However, the degree of impact of prior immunity on the power of epidemiological studies is not yet clear. This paper reports the results of some simple mathematical models of outbreaks of waterborne disease in populations with varying levels of immunity due to prior water and non-water exposure. The basic outbreak model was run on a spreadsheet. To determine the impact of prior immunity on case-control studies, further analysis was done using a Monte Carlo method to simulate sampling from cases and controls. It was found that moderate degrees of prior immunity due to water associated disease could markedly reduce the relative risk of water consumption on illness in waterborne outbreaks. In turn this would reduce the power of case-control studies. In addition, this model was used to demonstrate the impact of case misclassification and recall bias on case-control studies. Again it was found that within the model, the results of case-control studies could be significantly affected by both these sources of error. Anyone conducting epidemiological investigations of potentially waterborne outbreaks of disease should be aware of the epidemiological problems. Mistakes from case-control studies will be minimized if the outbreak team pays considerable attention to the descriptive phase of the investigation and if case-control studies are conducted as soon as possible after an outbreak is detected.