Microaerophilic organisms were monitored in sewage effluent undergoing two secondary treatments: air and oxygen-activated sludge. The mean numbers of Arcobacter cryaerophilus and thermophilic campylobacters detected in incoming sewage were 5639/100 ml and 1720/100 ml respectively.

Secondary treatment in air tanks reduced the population of A. cryaerophilus by 97.1% and of thermophilic campylobacters by 99.08%, whereas treatment in oxygen tanks reduced the bacteria 97.8% and 99.63% respectively, showing that oxygen-activated sludge treatment was more effective. Subsequent tertiary treatment with 2 p.p.m. chlorine dioxide evidenced the removal of A. cryaerophilus to 99.9% and eliminated thermophilic campylobacters.

Campylobacter jejuni and C. coli constituted 54.1% and 45.9% of 74 thermophilic campylobacter strains isolated. In air-activated sludge effluent C. jejuni was found more often, thus appearing more sensitive to oxygen.

The most probable number assay used for detection of campylobacters, blood medium for enrichment and blood-free medium for plating, also appeared to be fit for A. cryaerophilus, the high density of which in urban sewage may be due to inflows from slaughterhouses.

Sera from an age-stratified sample of 1810 people from the Caribbean island of St Lucia were tested for antibodies against varicella-zoster virus. The results indicate that very few infections occur in childhood, which agrees with clinical survey data from other tropical countries, but contrasts with the observed high case rate in children in temperate countries. The alternative hypotheses which may explain these results are discussed, and it is suggested that high ambient temperatures interfere with the transmission of the virus. Irrespective of the cause, the pattern of varicella incidence observed has important implications for any vaccination policy adopted in tropical countries.

One hundred faecal specimens, randomly collected from various locations within seven public parks in the west of Scotland, were examined for the presence of Giardia sp. cysts and Cryptosporidium sp. oocysts. Eleven percent of samples contained Giardia sp. cysts and 1 % contained Cryptosporidium sp. oocysts. Occurrence data from individual parks varied from 0 to 40% for Giardia and 0 to 2.4% for Cryptosporidium. The occurrence of parasitic organisms in public parks, especially in the vicinity of children’s playing areas is a matter of concern for public health officials and regulators of leisure and recreation amenities.

Excessive weight loss due to protein calorie malnutrition (PCM) is a significant problem in Nigerian children. This syndrome may be difficult to differentiate from the wasting disease caused by human immunodeficiency virus type 1 (HIV-1) infection. We studied 70 children admitted to the Baptist Medical Center in Ogbomosho, Nigeria in 1990 with PCM for prevalence of antibodies to HIV-1 and HIV-2. The cohort was from low-risk mothers and had a median age of 25 months (range, 4 months–9 years) with a weight deficit of at least 20% of the theoretical weight for age. Two sera were positive for anti-HIV-1 by both ELISA and Western blot (WB). A high prevalence of samples negative for HIV-1 antibody by ELISA were repeatedly reactive (11%, 8/70) or indeterminate (46%. 32/70) by WB. None of the sera was positive for antibody to HIV-2. There was no correlation of ELISA positivity or extent of WB banding with successful recovery from malnutrition. These results indicate a relatively low but significant prevalence of HIV-1 infection in Nigerian children with PCM. The high prevalence of indeterminate reactions in WB assays for HIV-1 suggests that other procedures may be necessary for confirmatory diagnosis of HIY-1 infection in this African population.

The sera of 3522 women who attended an antenatal clinic in Birmingham. England were tested anonymously for antibodies against HTLV-1. Samples from 5 women (0·14%) were positive, one serum showed indeterminate reactivity. Two of the women (0·06%) were born in the West Indies (of Afro-Caribbean ethnic origin), one (0·03%) in Africa (of African ethnic origin), and three (0·09%) were white Caucasian women born in the UK. Thus, HTLV-1 infection in pregnant women in the UK, though comparatively rare, is not negligible. As transmission of HTLV-1 to the newborn via breast milk has been observed and as seropositive mothers can be advised to refrain from breastfeeding or to treat their milk, the question of routine screening for HTLV-1 infection during antenatal care is discussed.

Serological tests are very frequently used in epidemiological surveys of leishmaniasis and other parasitoses. Their sensitivity and specificity are generally defined with respect to parasitism and diseases, rather than infection. The reason is that known positives are those individuals most likely to yield parasites, or who have distinctive clinical signs, and concomitantly high antibody titres. This paper investigates the performance of one serological method, the indirect fluorescent antibody test (IFAT), in detecting Leishmania infantum infection during an intensive 2-year cohort study of dogs in southern France. The results show that sensitivity and specificity with respect to infection can be simultaneously high, but maximum sensitivity is probably <80%, and lasts for a relatively short period of 2–3 months after a lengthy incubation period. The IFAT gave the incidence of infection as 18–65% in the first year, whereas the best estimate of incidence based on parasite isolation and clinical observation was 72%. But data from the second year suggest that the 72% was itself an underestimate. We argue that, during epidemiological surveys, the IFAT in particular, and serological tests for leishmania in general, will underestimate prevalence, incidence and hence the scale of the control problem. However, there is evidence that tests for canine leishmaniasis employing high threshold titres will identify the most infectious animals, allowing selective treatment or culling of those which contribute disproportionately to transmission.

Ten coxsackievirus B4 (CVB4) strains isolated from clinical and environmental sources in Northern Ireland in 1985–7, were compared at the nucleotide sequence level. Dideoxynucleotide sequencing of a polymerase chain reaction (PCR) amplified fragment, spanning the VP1/P2A genomic region, classified the isolates into two distinct groups or genotypes as defined by Rico-Hesse and colleagues for poliovirus type 1. Isolates within each group shared approximately 99% sequence identity at the nucleotide level whereas ≤86% sequence identity was shared between groups. One isolate derived from a clinical specimen in 1987 was grouped with six CVB4 isolates recovered from the aquatic environment in 1986–7. The second group comprised CVB4 isolates from clinical specimens in 1985–6. Both groups were different at the nucleotide level from the prototype strain isolated in 1950. It was concluded that the method could be used to sub-type CVB4 isolates and would be of value in epidemiological studies of CVB4. Predicted amino acid sequences revealed non-conservation of the tyrosine residue at the VP1/P2A cleavage site but were of little value in distinguishing CVB4 variants.

A 13-month study of wild mice (Mus domesticus) in wheatlands in southeastern Australia contrasted changes in the seroprevalence of antibody to 13 viruses and the occurrence of helminths with changes in their population dynamics. Mice were seropositive for mouse hepatitis virus (MHV), rotavirus, minute virus of mice (MVM), mouse adenovirus (MAdV), reovirus (reo 3), and murine cytomegalovirus (MCMV). The seroprevalences of all but rotavirus varied significantly with time and increased with host density. Near the end of the study, host density declined rapidly and the seroprevalence of MVM and reo 3 increased significantly. These two viruses had low seroprevalence when host survival was high and high seroprevalence when host survival was low, indicating they may play a role in regulating mouse populations. In the case of MVM, there was evidence of a viral epizootic during the decline in mouse abundance. The prevalence of four helminths (Taenia taeniaeformis, Syphacia obvelata, and Vampirolepis spp.) differed significantly with time but showed no apparent association with host density. These findings highlight the need for further study on the effect of viruses on the population dynamics of mice.

Human rotavirus strains from Kenya, from children with gastroenteritis in an urban area (Nairobi) and three rural areas were characterized by antigenic and genomic analysis. While in all areas strains with subgroups II and G serotype 1 antigens were most common, two unusual strains were detected. One strain (NK59: subgroup II. G serotype 4) possessed an additional RNA band on polyacrylamide gel electrophoresis, the other (D202) which had antigenic specificity of subgroup II and G serotype 1 showed a ‘short’ RNA pattern. The latter strain was adapted to growth in cell culture.