Serum antibodies against Borrelia afzelii, Borrelia burgdorferi sensu stricto and the 41-kiloDalton flagellin in patients from a Lyme borreliosis endemic area: analysis by EIA and immunoblot.

To evaluate the possible importance of antigenic heterogeneity in the serological diagnosis of Lyme borreliosis a study was performed using antigens from various Lyme Borrelia strains. Serum samples from 102 patients with clinical signs of the infection, all living in an endemic area in southern Sweden, were evaluated by four enzyme immuno assays (EIA). The sera were initially tested for the immunoglobulin G response to antigens from a local Borrelia afzelii strain (ACA1). Serum samples from healthy blood donors residing in the same region were used to define seropositivity in the ACAI-EIA. Immunoblotting was performed with the ACAI antigen and the reactive bands were analysed. A serum was defined as positive when at least four of the Borrelia specific polypeptides (OspC, OspA, OspB, p39, p41 [flagellin], p83, p94, 110kDa) were stained. The same sera were then analysed in three other IgG enzyme immunoassays, one based on antigens from Borrelia burgdorferi sensu stricto B31, and another on pooled protein fractions from strains B31 and ACAI. In the third EIA, sera were analysed for antiflagellin reactivity (B, afzelii strain DK-1). An inconstant immune response was demonstrated in the EIAs and the seropositivity varied between 30-47% when low positive values were excluded, and between 38-73% if all values were included. Fifty sera (50/102) met the criteria for a positive immunoblot, but positive immunoblots were detected with both low positive and negative sera independent of antigen used in the EIAs. Antigens of the local B. afzelii strain were found to detect a higher number of seropositive individuals, which suggests that the antibody reactivity to Lyme Borrelia increases when antigens from a strain endemic in a particular geographical region are used. Data from this study suggest that EIA alone seems insufficient for the serodiagnosis, and antigenic heterogeneity of Lyme Borrelia spp. influences the performance of serum antibody tests. The reliability of serological assays could be increased when the serum antibodies against antigens of Borrelia spp. predominant in the local geographical region are measured.

Haemophilus influenzae causing conjunctivitis in day-care children.

The role of Haemophilus influenzae in acute purulent conjunctivitis was studied during an outbreak among children in day care. Five day-care centers contributed 20 cases and 35 controls. All the children were subjected to culture of the nasopharynx and the eyes. H. influenzae was carried in the nasopharynx of 53% of the children (range between day care centers, 20 to 91%). Of the 20 children with acute conjunctivitis 8 had eye cultures positive for H. influenzae, 2 had Moraxella and the remaining were culture-negative. Ten colonies of H. influenzae were isolated from each positive culture and identified by capsular type, biotype and multi-locus enzyme electrophoresis. All but one of the isolates were nonencapsulated. They belonged to 4 biotypes and 8 electrophoretic types. The same strain was recovered from the eyes and nasopharynx of the symptomatic children, suggesting that the H. influenzae in the eyes originated from the nasopharynx. There was no evidence for spread of the same H. influenzae strains between day-care centers. Even within each center the Haemophilus strains recovered from the eyes varied among the symptomatic children. The in vitro capacity to attach to oropharyngeal epithelial cells was not increased among the H. influenzae recovered from the eyes. The results question if the majority of conjunctivitis cases were caused by H. influenzae and suggested that eyes were colonized with the nasopharyngeal carrier strain rather than infected by an isolate with special virulence for the eye.