Development of human papillomavirus chimaeric L1/L2 candidate vaccines.

Recombinant human papillomavirus (HPV) virus-like particle (VLP) vaccines based on the L1 capsid protein have been shown to be efficient prophylactic vaccines, albeit type-specific. As a first step to investigate the feasibility of extending protection against non-vaccine types, HPV-16 L1 chimaeras were generated. The region downstream of L1 amino acid (aa) 413 was replaced with selected cross-neutralising epitopes (aa 108-120; 56-81 and 17-36) derived from the HPV-16 L2 protein, generating proteins designated SAF, L2.56 and L2.17, respectively. The chimaera L1BPV containing BPV-1 L2 peptide aa 1-88 was similarly constructed. The chimaeras were evaluated for expression in insect cells; their ability to form particles was studied by electron microscopy, and their immunogenicity was evaluated in mice. SAF, L2.56 and L2.17 proteins were expressed to high concentrations in insect cells and elicited HPV-16 pseudovirus-neutralising anti-L1 antibodies. L2.56 and L2.17 also elicited anti-L2 antibodies. L1BPV was a poor vaccine candidate due to low levels of expression with concomitant lack of immunogenicity. All chimaeras assembled into tertiary structures. The results indicate that chimaeric L1 vaccines incorporating cross-neutralising L2 peptides could be promising second-generation prophylactic HPV vaccine candidates.

A unique isolate of beak and feather disease virus isolated from budgerigars (Melopsittacus undulatus) in South Africa.

Beak and feather disease virus (BFDV), the causative agent of psittacine beak and feather disease (PBFD) infects psittaciformes worldwide. We provide an annotated sequence record of three full-length unique genomes of BFDV isolates from budgerigars (Melopsittacus undulatus) from a breeding farm in South Africa. The isolates share >99% nucleotide sequence identity with each other and approximately 96% nucleotide sequence identity to two recent isolates (Melopsittacus undulatus) from Thailand but only between 91.6 and 86.6% identity with all other full-length BFDV sequences. Maximum-likelihood analysis and recombination analysis suggest that the South African budgerigar BFDV isolates are unique to budgerigars, are non-recombinant in origin, and represent a new genotype of BFDV.

The incidence and clinical presentation of infantile rotavirus diarrhoea in Sierra Leone.

OBJECTIVES: An effective vaccine is needed to protect against severe rotavirus disease, an important cause of gastroenteritis. Since there are no data on the incidence and antigenic diversity of rotavirus infection in Sierra Leone, we studied its epidemiology to enable an effective vaccine strategy to be designed. METHODS: Children between the ages of 3 and 30 months presenting with gastroenteritis to the Ola During Children's Hospital in Freetown, Sierra Leone, were enrolled. Stool specimens were tested in South Africa using polyacrylamide gel electrophoresis to confirm rotavirus infection. RESULTS: Over a 5-month period 143 children presenting with gastroenteritis were recruited. Stool samples obtained from 128 study subjects were tested for the presence of rotavirus; 45% were aged between 3 and 9 months (mean age 10.85 months), and 48 stool samples (37.5%) tested positive for rotavirus. The incidence of rotavirus infection was 20% higher in boys than in girls, a gender difference confirmed elsewhere in West Africa. The prevalence of rotavirus-positive stools peaked in August, coinciding with the rainy season. About 90% of the rotavirus-positive patients had severe diarrhoea, as opposed to only about two-thirds of the patients whose diarrhoea was not caused by rotavirus; this difference was statistically significant. CONCLUSIONS: There is a high incidence of rotavirus infection in Sierra Leone, with rotavirus causing 37.5% of the gastroenteritis in this study. Patients with rotavirus gastroenteritis almost all had severe diarrhoea. The high incidence of rotavirus infection and the severity of the disease presentation make the institution of a rotavirus vaccine programme in Sierra Leone imperative.