Per C. Grauballe

Antibody response in serum and intestine in children up to six months after a naturally acquired rotavirus gastroenteritis.

Summary The aim of this study was to provide detailed information about the local and systemic antibody response and their relationship following a rotavirus gastroenteritis. Rotavirus-specific immunoglobulins were analyzed by enzyme-linked immunosorbent assay (ELISA). The study included 49 children referred to hospital with rotavirus gastroenteritis and 16 children with nonrotavirus gastroenteritis. The concentrations of rotavirus immunoglobulin A (IgA) in serum increased within the first 2 weeks and those of rotavirus IgG within the first month after the onset of diarrhea. Thereafter, they remained unchanged during the 6-month observation period. Rotavirus ScIg (i.e., antirotavirus immunoglobulin-containing secretory component) appeared in serum almost exclusively within 7–14 days after onset (i.e., 85% of the samples). After the first 2 weeks, rotavirus IgA could be detected in the majority of fecal samples, even up to 6 months after the disease. However, rotavirus ScIg was absent in the majority of fecal samples. The severity of illness correlated only with the increase of rotavirus IgG in serum. Conclusively, there is a longstanding immune response after a naturally acquired rotavirus gastroenteritis. Moreover, with the present methods, measurements of rotavirus IgA and IgG in serum can be safely used for serodiagnosis, even when samples are taken with 6-month interval. It is suggested that trials with rotavirus vaccines include measurements of rotavirus IgA and ScIg in serum and rotavirus IgA in feces.

Acute gastroenteritis in children attending day-care centres with special reference to rotavirus infections. I. Aetiology and epidemiologic aspects.

Acute gastroenteritis (GE) among 214 children (aged 6 months – 7 years) attending day‐care centres (DDCs) in the Copenhagen County was studied during a 12‐month period. A total of 197 cases of GE was observed in 109 children (i.e. 51% of the participants). The aetiology was as follows: rotavirus (n=48) (24%), pathogenic bacteria (n=11) (6%), Giardia lamblia (n=3) (2%), while the aetiology of 68% remains unknown. The pathogenic bacteria included Yersinia enterocolitica, thermophilic Campylobacter, Clostridium difficile (±toxin) and enteropathogenic E. coli. In 4% of the GE the infections were multiple and Cryptosporidium was seen in one of these cases. The rate of GE declined with age from 1.35 GE per child per year (age group 1.0– <2.0 years) to 0.36 (6.0 – <8.0 years). Serum sampled at the start of the study period showed that the frequency of detectable rotavirus IgG increased with age from 48% in the 6 months – <1.0 year group to 96% in the 4.0 – <7.0 year group. The highest rates of rotavirus GE occurred from January to April (i.e. the rotavirus season). Moreover, rotavirus GE was almost absent after the age of 4. Hence, the rates of rotavirus GE per rotavirus season per child were 0.80 (age group 6 months–<1.0 year), 0.32 (1.0–<2.0), 0.14 (2.0–<3.0), 0.16 (3.0–<4.0), 0.06 (4.0–<5.0) and 0.04 (5.0–<6.0). Only 2 out of the 48 rotavirus GE were reinfections. The 32 children with asymptomatic rotavirus infections and those with rotavirus GE showed a similar distribution of age and season. A cross‐sectional study of the prevalence of rotavirus excretion during the rotavirus season revealed only a single true asymptomatic excretor.

Intestinal and serum immune response to a naturally acquired rotavirus gastroenteritis in children.

Seventeen children (mean age: 2.0 years, range: 36 days-8 years) hospitalized with acute gastroenteritis were investigated. Thirteen children had a rotavirus infection while four did not. Rotavirus serum IgA as well as ScIg, i.e., antirotavirus immunoglobulin containing secretory component, increased rapidly after rotavirus infection. While rotavirus IgA persisted in serum for at least 6 months, rotavirus ScIg disappeared from serum in less than 4 months. Rotavirus IgG could be detected in serum during the early stage of the infection and was still high after 6 months. The patients with nonrota-virus acute gastroenteritis did not show any of the above-mentioned serological hallmarks of those with rotavirus infection. The amounts of rotavirus ScIg found in serum about 1 week after the infection correlated to the amounts of rotavirus ScIg in duodenal fluid. Six months after the infection, rotavirus IgA was found in the feces of the majority of the patients while rotavirus ScIg could be detected only in one patient. The amounts of rotavirus IgA in sera and intestinal secretions showed identical patterns in the acute phase of the disease as well as after recovery. The same applied to rotavirus ScIg. These findings could be useful in future evaluations of vaccines and immunity against rotavirus infections.

Crossed immunoelectrophoretic identification of partially purified type common and type specific herpes simplex virus glycoprotein antigens.

Summary HSV glycoprotein antigens obtained from Triton X-100-solubilized type 1- and type 2-infected cells were partially purified by ion-exchange chromatography and analyzed by crossed immunoelectropho-resis in Triton X-100 containing agarose gel. Two HSV type common, two HSV type 1 specific, and one HSV type 2 specific antigens were identified. Rabbits immunized with the HSV glycoprotein preparations developed strong viral-neutralizing antibodies.

Acute gastroenteritis in children attending day-care centres with special reference to rotavirus infections. II. Clinical manifestations.

In a prospective study of a cohort of 214 children (aged 6 months – 7 years) attending day‐care centres, a total of 197 episodes of acute gastroenteritis (GE) occurred in 109 children (i.e. 51% of the participants) during a 12‐month observation period. Rotavirus, pathogenic bacteria and Giardia lamblia caused GE in 24%, 6% and 2% of the cases, respectively. The aetiology of the remaining 68% was not discovered. Generally, the symptoms of GE were light and only two episodes led to hospitalization. Thirty‐two rotavirus infections were asymptomatic. Two rotavirus GE reinfections occurred. They showed less severe symptoms than the primary infections. The older children (>1.5 years) with rotavirus GE had lighter symptoms than the younger ones (1.5 years). Compared with children with non‐rotavirus GE, those with rotavirus GE showed the following clinical features: (1) Age between 6 months and 2 years. (2) Occurrence of rotavirus GE almost exclusively during the rotavirus season, i.e. January to April (winter). (3) High frequency of vomiting, the onset of which often preceded that of diarrhoea. However, these signs did not form a safe basis for the clinical diagnosis of rotavirus GE. One or more upper respiratory manifestations (URM) were observed in 39% of the children with rotavirus GE and in 36% of those with non‐rotavirus GE. The occurrence of URM was age‐related being highest in children less than 2 years. Consequently, the existence of a rotavirus syndrome is questioned. It is argued that URM in children with rotavirus GE may be due to a co‐infection of the upper respiratory tract by a different micro‐organism.

Comparison of Diagnostic Procedures for Bovine Rotavirus

Faecal samples or intestinal contents from 92 fatal cases of neonatal diarrhoea in calves were tested for rotavirus by the following methods. Electron microscopy (EM) was performed as previously described, by negative staining of bands obtained after centrifugation of clarified faecal suspensions on CsCl-gradients (Grauballe et al., 1977). Detection of fluorescent antigen by the use of FITC-conjugated rabbit anti bovine rotavirus antibodies (FA) was performed in two ways: either by direct staining of smears from intestinal contents or by staining of primary bovine kidney cells previously inoculated with the specimen as described (Meyling, 1974). Immunoelectro-osmophoresis (IEOP) and enzyme-linked immuno-sorbent assay (ELISA) were performed according to the manuals presented at this meeting, using the same antibodies for both assays, i.e. second generation poly-specific antibodies to human rotavirus prepared in rabbits by injection of immunoprecipitates as previously described (Grauballe et al., 1979).