The antigenic diversity of rotaviruses: significance to epidemiology and vaccine strategies

A perspective on the 2009 A/H1N1 influenza pandemic in Mexico

In this article, we provide a chronological description of the 2009 H1N1 influenza pandemic in Mexico from the detection of severe respiratory disease among young adults in central Mexico and the identification of the novel swine-origin influenza virus to the response of Mexican public health authorities with the swift implementation of the National Preparedness and Response Plan for Pandemic Influenza. Furthermore, we review some features of the 2009 H1N1 influenza pandemic in Mexico in relation to the devastating 1918-1920 influenza pandemic and discuss opportunities for the application of mathematical modeling in the transmission dynamics of pandemic influenza. The value of historical data in increasing our understanding of past pandemic events is highlighted.

The impact of vaccines and vaccinations: Challenges and opportunities for modelers

This review focuses on how infectious diseases and their prevention and control by development of vaccines and widespread vaccination has shaped evolution of human civilization and of the animals and plants that humans depend on for food, labor and companionship. After describing major infectious diseases and the current status for control by vaccination, the barriers to infection and the attributes of innate and acquired immunity contributing to control are discussed. The evolution in types of vaccines is presented in the context of developing technologies and in improving adjuvants to engender enhanced vaccine efficacy. The special concerns and needs in vaccine design and development are discussed in dealing with epidemics/pandemics with special emphasis on influenza and current global problems in vaccine delivery.

A combined staphylococcal coagglutination assay for rapid identification of rotavirus and adenovirus (COARA)

An improved staphylococcal coagglutination test was developed for rapid detection, in a single assay, of rotavirus and adenovirus in stool samples (COARA). Suspensions of Staphylococcus aureus coated respectively with anti-rotavirus and anti-adenovirus sera were used to identify these viruses in 327 stool samples of children. The samples were also tested by an enzyme immunoassay. The data analysis has demonstrated a high degree of correlation between the two assays.

Electropherotypes and serotypes of human rotavirus in Estonia in 1989-1992

The electropherotypes and serotypes of human rotaviruses circulating in Tallinn (Estonia) in 1989-1992 have been studied. Rotaviruses were found in 372 (25.8%) of 1,442 faecal specimens of pediatric patients with acute diarrhea. Polyacrylamide gel electrophoresis of RNA from 318 isolates has revealed 41 electropherotypes. Frequent genomic alterations, including a shift of predominant electropherotypes, were observed during the study period. The serotype of 158 (50.3%) of 314 tested rotavirus isolates was identified using ELISA with VP7-specific monoclonal antibodies against 4 established human rotavirus serotypes. Serotype G1 was found to be largely predominant and accounted for 70.9% of the typeable specimens, serotypes G4, G2, and G3 accounted for 12%, 9.5%, 7.6%, respectively. A major shift to serotype G4 took place in 1990-1991. Serotype G1 was represented by the largest number of electropherotypes. All G1, G3 and G4 isolates were of "long" and all G2 isolates were of "short" electropherotypes. According to our results the isolates of an identical electropherotype belong to the same serotype.

Homotypic and heterotypic immune responses to group A rotaviruses in parenterally immunized sheep

Immune responses to human rotaviruses were investigated in sheep with a view to obtaining antibodies for passive immunotherapy of humans. Eighteen adult sheep with previous natural exposure to rotavirus serotypes G3 and G6 were immunized parenterally with purified preparations of either individual rotavirus serotypes G1, G2, G3, G4 and G8, or a mixture thereof. Two additional sheep were kept as control animals with the flock. The antibody responses were measured on serial serum samples by neutralization tests. The homotypic antibody response ranged from 100-fold (rarely) up to 100,000-fold increases in titre. Heterotypic responses against serotypes G3 and G6 were demonstrated in 7/12 and 15/18 sheep, respectively, but the increases in titre were lower than the homotypic responses, ranging from 10- to 100-fold in most cases and were 1000-fold in two sheep. Interestingly, no heterotypic response against the human rotavirus serotypes was raised after 3 months; moderate titres of cross-neutralizing antibodies for the human serotypes were only observed after a third inoculation.

Direct serotyping of porcine rotaviruses using VP7-specific monoclonal antibodies by an enzyme immunoassay

Employing a serotyping EIA test using MAbs both cell culture adapted and faecal porcine rotaviruses were classified into serotypes G3, G3/5, G4, and G5. The MAbs have confirmed and extended the serotyping results obtained using polyclonal antisera. These MAbs are therefore potential reagents for serotyping of porcine rotaviruses. Using subgroup specific MAbs serotypes G3, G3/5, and G5 were found to contain subgroup I antigens while G4 rotaviruses contained either subgroup II or subgroup I antigens.

VP4 relationships between porcine and other rotavirus serotypes

VP4 relationship of Australian porcine rotaviruses were identified using genetic reassortants and MAbs. All porcine virus isolates except BEN-144 appeared to share VP4 antigenicity with OSU virus. VP4 and BEN-144 virus (Gottfried-like virus) showed some antigenic relationships with the human neonatal viruses ST-3 and RV-3. In addition, VP4 of porcine CRW-8 showed antigenic relationships with simian SA-11. RRV and also canine K9 viruses, while that of porcine TFR-41 showed at least one way VP4 antigenic relatedness with UK bovine rotavirus. Furthermore, BMI-1 virus which is antigenically similar to an American virus SB1-A (a naturally occurring reassortant) may have arisen similarly by gene reassortment in nature in Australia.

Neutralizing monoclonal antibodies against three serotypes of porcine rotavirus

Using three serotypes (four strains) of cultivable porcine rotavirus as immunizing antigens, 10 neutralizing monoclonal antibodies were characterized. One VP4-specific monoclonal antibody directed against porcine rotavirus BEN-144 (serotype G4) neutralized human rotavirus strain ST-3 in addition to the homologous porcine virus. All nine VP7-specific monoclonal antibodies were highly specific for viruses of the same serotype as the immunizing rotavirus strain. One exception was the VP7-specific monoclonal antibody C3/1, which neutralized both serotype G3 and G5 rotaviruses. However, this monoclonal antibody did not neutralize the porcine rotavirus AT/76, also of serotype G3, nor mutants of SA-11 virus (serotype G3) which were selected with monoclonal antibody A10/N3 and are known to have mutations affecting the C antigenic region.

Determination of rotavirus serotype-specific antibodies in sera by competitive enhanced enzyme immunoassay

A method is described for the specific detection of antibody to individual rotavirus serotypes in sera. A competitive enzyme immunoassay (EIA) was developed in which rotavirus serotype-specific monoclonal antibodies against VP7 compete with antibodies in test sera for rotavirus serotype-specific antigen bound to a solid phase. There was an excellent correlation between serotype-specific EIA results and serotype-specific neutralization titres (r = 0.915, P = less than 0.001). The value of this method for rotavirus epidemiology and vaccine trials is discussed.