Rotavirus diarrhea severity is related to the VP4 type in Mexican children

Genotyping and clinical factors in pediatric diarrhea caused by rotaviruses: one-year surveillance in Surabaya, Indonesia

BACKGROUND

Rotavirus infections are a major cause of diarrhea in children in both developed and developing countries. Rotavirus genetics, patient immunity, and environmental factors are thought to be related to the severity of acute diarrhea due to rotavirus in infants and young children. The objective of this study was to provide a correlation between rotavirus genotypes, clinical factors and degree of severity of acute diarrhea in children under 5 years old in Surabaya, Indonesia.

METHODS

A cross-sectional study was conducted in children aged 1-60 months with acute diarrhea hospitalized in Soetomo Hospital, Surabaya, Indonesia from April to December 2013. Rotavirus in stool specimens was identified by ELISA and genotyping (G-type and P-type) using multiplex reverse transcription PCR. Severity was measured using the Ruuska and Vesikari scoring system. The clinical factors were investigated included patient's age (months), hydration, antibiotic administration, nutritional state, co-bacterial infection and co-viral infection.

RESULTS

A total of 88 children met the criteria; 80.7% were aged 6-24 months, watery diarrhea was the most common type (77.3%) and 73.6% of the subjects were co-infected with bacteria, of which pathogenic Escherichia coli was the most common (42.5%). The predominant VP7 genotyping (G-type) was G2 (31.8%) and that of VP4 genotyping (P-type) was P[4] (31.8%). The predominant rotavirus genotype was G2P[4] (19.3%); G1P[4] and G9P[4] were uncommon with a prevalence of 4.5%. There were significant differences between the common genotype and uncommon genotype with respect to the total severity score of diarrhea (p <0.05). G3, G4 and G9 were significantly correlated with severe diarrhea (p = 0.009) in multivariate analyses and with frequency of diarrhea (>10 times a day) (p = 0.045) in univariate analyses, but there was no significant correlation between P typing and severity of diarrhea. For combination genotyping of G and P, G2P[4] was significantly correlated with severe diarrhea in multivariate analyses (p = 0.029).

CONCLUSIONS

There is a correlation between rotavirus genotype and severity of acute diarrhea in children. Genotype G2P[4] has the highest prevalence. G3, G4, G9 and G2P[4] combination genotype were found to be associated with severe diarrhea.

Diarrhoea caused by rotavirus in a regional Peruvian hospital: determination of circulating genotypes

BACKGROUND

Gastroenteritis caused by rotavirus is responsible for approximately 810 deaths per year in children under 5 years of age in Peru and emerging rotavirus genotypes have led to concerns regarding cross-protection by the vaccines available. Moreover, there are no reports on the molecular epidemiology of rotavirus diarrhoea in Peru.

METHODS

A total of 131 stool samples were obtained from children under 5 years hospitalised from January 2010 to December 2012 in the Hospital Regional de Cajamarca (Peru). ELISA and RT-PCR techniques were performed for rotavirus detection. G and P typing of rotavirus-positive samples were performed by semi-nested multiplex RT-PCR, and sequencing was performed to confirm the PCR results.

RESULTS

Of the 117 samples available, 22 (18.8%) tested positive for rotavirus by ELISA and 42 (35.9%) tested positive by RT-PCR. Among the G genotypes identified, G9 (35.7%; 15/42) and G12 (33.3%; 14/42) were the most prevalent, with the most common combination being G12/P[6] (23.8%; 10/42).

CONCLUSIONS

A high prevalence of the G12/P[6] genotype was detected. It is known that this genotype is not covered by the current vaccines available. More in-depth studies are needed to determine the current rotavirus genotypes presents in Peru.

Rotavirus genotype distribution during the pre-vaccine period in Bolivia: 2007-2008

OBJECTIVES

Rotavirus is the most important etiology of severe diarrhea in Bolivia. The monovalent attenuated human oral rotavirus vaccine Rotarix(®) was introduced in Bolivia in 2008. We describe the molecular epidemiology of circulating rotavirus strains before vaccine introduction.

METHODS

Two thousand one hundred thirty-five diarrheal samples were collected from hospitals in four Bolivian cities during 2007-2008. Forty-three percent (445 of 1030 rotavirus-positive samples) were analyzed for G and P genotypes. Among those, 331 were electropherotyped by polyacrylamide gel electrophoresis. Disease severity was quantified using a modified Vesikari scale.

RESULTS

Among the 445 samples, five genotypes were found to be prevalent: G9P[8] (33%), G1P[6] (17%), G2P[4] (13%), G9P[6] (12%), and G1P[8] (4%). Co-infections with two or more strains accounted for 14% of samples. The most prevalent strain, G9, showed greater electropherotype diversity compared to other serogroups. Strain G1P[6] generally infected younger children and peaked later in the year than other strains. No particular genotype was associated with a higher severity score, though there was a significant difference in the duration of diarrhea between genotypes.

CONCLUSIONS

During the 2-year pre-vaccine period, substantial diversity of rotavirus co-circulating strains was observed. These data constitute a baseline against which changes in circulating strains post-vaccine introduction can be monitored.

[Comparison of clinical characteristics of patients with rotavirus gastroenteritis relative to the infecting rotavirus g-p genotype.]

BACKGROUND

Group A rotavirus is a major cause of severe diarrhea in children throughout the world. For the proper management of rotavirus infections, it will be helpful to know their clinical characteristics according to the G and P genotypes of the infecting virus.

METHODS

The diarrheal stool specimens from patients hospitalized in Chosun University Hospital during 2002-2003 were tested for rotavirus by Dipstick 'Eiken' Rota kit. Rotavirus antigen-positive stool specimens were analyzed for group A rotavirus by RT-PCR, and the group A-positive PCR products were genotyped for P and G types by PCR.

RESULTS

Among the 119 specimens analyzed for genotypes, the predominant strain was genotype G4P[6] (51.3%), followed by G2P[4] (19.3%), G1P[8] (7.6%), G3P[8] (5.0%), and G9P[8] (4.2%). To examine the characteristics of each rotavirus genotype, a clinico-epidemiological study was performed for 100 patients whose medical records were available. The frequencies of diarrhea, vomiting, dehydration, and fever; the rates of nosocomial infection and transfer from other hospitals; and the mean severity scores were significantly different among the patients infected with different types of rotavirus. Especially, patients with G4P[6] type were more likely than those infected with other genotypes to show the following distinct features: Most patients showed milder symptoms and were neonates transferred from other obstetric hospitals and 68.4% of the cases were nosocomial infection. G4P[6] strains were isolated almost all along the year. The mean severity scores of patients infected by G4P[6], G2P[4], G1P[8], G3P[8], and G9P[8] strains were 6.8, 9.5, 8.0, 9.0, and 10.8, respectively.

CONCLUSIONS

Many features of rotavirus infections including the epidemic period, rate of nosocomial infection, age and severity of symptoms were different according to the genotypes of the infecting virus.

Severity of acute gastroenteritis in infants infected by G1 or G9 rotaviruses

BACKGROUND

Group A rotaviruses are the main viral causative agent of acute diarrhea, and cause considerable morbidity in children. G9 rotaviruses have recently emerged all over the world and are thought to give more severe symptoms because of a lack of previous exposure and the absence of maternal antibodies in patients.

OBJECTIVES

To determine the clinical severity of G9 infections compared to G1 infections in hospitalized children.

STUDY DESIGN

The prospective study was conducted from 2004 to 2007 in French children under 5 years old hospitalized for acute gastroenteritis. The rotaviruses were detected in stools by ELISA tests and genotyped by RT-PCR on the basis of their outer capsid proteins. The duration of hospitalization, the Vesikari clinical score, and the requirement for intravenous rehydration were compared.

RESULTS

The stools from 370 children were analyzed and 162 stools infected by G1 (n=76) or G9 (n=86) rotaviruses were analyzed. Age and gender distribution were similar in the two groups as was the mean duration of hospitalization (2.7 days). The Vesikari scores were 12.96 and 12.83 in G1P[8] and G9P[8] groups (p=0.417), respectively, in which 55.3 and 53.5% of the children, respectively, were rehydrated with an intravenous line.

CONCLUSIONS

No difference in severity was found between G1 and G9 rotavirus infections. Rigorous surveillance to monitor changes in the ecology of rotavirus infections is necessary, as emerging strains are more likely to cause severe gastroenteritis and not respond to current rotavirus vaccines.

Age and gender specific prevalence of HTLV-1

BACKGROUND

The seroprevalence of Human T-cell Leukemia Virus Type 1 (HTLV-1) is female predominant despite the higher incidence of Adult T-cell Leukemia (ATL) in males. If the mother-to-child transmission of HTLV-1 is more common for male infants than in female infants, longer exposure to the virus for males may explain the paradoxically higher incidence of ATL.

OBJECTIVES

To test the hypothesis that the seroprevalence of HTLV-1 is male predominant during adolescence.

STUDY DESIGN

The presence of HTLV-1 antibody in 272,043 blood samples donated to a regional blood bank in an HTLV-1 high-endemic region was assessed.

RESULTS

The entire population of female donors had a significantly higher seroprevalence compared to males (2.05% and 1.80%, respectively, p<0.0001). However, compared with male donors, the carrier rate for female donors was lower for the youngest subgroup (16-19 years, p=0.0011); was similar for the next two age subgroups (20-29 years and 30-39 years); and was significantly higher for the last two age subgroups (40-49 years and over 50-64 years, both p<0.0001). In general, older age subgroups led to higher seroprevalence in both genders.

CONCLUSIONS

HTLV-1 infection is more common for males until after age 20, when male to female sexual transmission becomes likely. This suggests that mother-to-child transmission is more common for males.

Cost-effectiveness of introducing a rotavirus vaccine in developing countries: the case of Mexico

Background

In developing countries rotavirus is the leading cause of severe diarrhoea and diarrhoeal deaths in children under 5. Vaccination could greatly alleviate that burden, but in Mexico as in most low- and middle-income countries the decision to add rotavirus vaccine to the national immunisation program will depend heavily on its cost-effectiveness and affordability. The objective of this study was to assess the cost-effectiveness of including the pentavalent rotavirus vaccine in Mexico's national immunisation program.

Methods

A cost-effectiveness model was developed from the perspective of the health system, modelling the vaccination of a hypothetical birth cohort of 2 million children monitored from birth through 60 months of age. It compares the cost and disease burden of rotavirus in an unvaccinated cohort of children with one vaccinated as recommended at 2, 4, and 6 months.

Results

Including the pentavalent vaccine in the national immunisation program could prevent 71,464 medical visits (59%), 5,040 hospital admissions (66%), and 612 deaths from rotavirus gastroenteritis (70%). At US$10 per dose and a cost of administration of US$13.70 per 3-dose regimen, vaccination would cost US$122,058 per death prevented, US$4,383 per discounted life-year saved, at a total net cost of US$74.7 million dollars to the health care system. Key variables influencing the results were, in order of importance, case fatality, vaccine price, vaccine efficacy, serotype prevalence, and annual loss of efficacy. The results are also very sensitive to the discount rate assumed when calculated per life-year saved.

Conclusion

At prices below US $15 per dose, the cost per life-year saved is estimated to be lower than one GNP per capita and hence highly cost effective by the WHO Commission on Macroeconomics and Health criteria. The cost-effectiveness estimates are highly dependent upon the mortality in the absence of the vaccine, which suggests that the vaccine is likely to be significantly more cost-effective among poorer populations and among those with less access to prompt medical care – such that poverty reduction programs would be expected to reduce the future cost-effectiveness of the vaccine.

A lack of significant association between the electropherotype or G-serotype of the infecting strain and disease severity of rotavirus gastroenteritis

Despite many previous studies, the question has not been settled as to whether some human rotavirus strains are more virulent than others. Since disease severity is most clearly reflected by the hospitalization status of the infected children, we examined whether there was any difference in the distribution of dominant strains between inpatient and outpatient groups. The study population comprised 763 children with acute diarrhea who were treated at a general hospital in Honjo City, Akita, Japan, during 1986-1997. Rotaviruses from stool specimens were classified into 77 electropherotypes using polyacrylamide gel electrophoresis. A single dominant strain or two co-dominant strains circulated simultaneously with some infrequent strains in most rotavirus seasons. Over the 11 rotavirus seasons, there was no significant difference in the relative frequencies of 15 rotavirus strains between the inpatient and the outpatient groups when strains of rotavirus were defined by their electropherotypes in polyacrylamide gel electrophoresis. However, infection with one G1 strain that co-dominated with a G4 strain carrying an identical electropherotype except the VP7 gene resulted in a statistically significantly reduced risk of hospitalization. There was no significant difference in the relative frequencies of four major G-serotypes or long/short RNA pattern. We conclude that the virulence or disease-causing potential of human rotavirus is not substantially different in the majority of strains.

Rotavirus vaccine: early introduction in Latin America-risks and benefits

Rotavirus infection is the cause of severe gastroenteritis of young children worldwide, leading to an estimate of 600,000 deaths a year. Efforts to develop an effective and safe vaccine resulted in licensing in 1998 of a live oral vaccine (RotaShield) that was withdrawn less than 1 year later when reports of cases of intussusception were linked to its application. This led to development of new rotavirus vaccine candidates that are currently in late phase III clinical trials. One of these vaccines, GlaxoSmithKline's Rotarix, was licensed in July 2004 to be used in Mexico. This review describes the general background for rotavirus vaccine development, the different vaccine candidates that have been tested or are currently being evaluated, the association of rotavirus vaccination with the bowel blockage known as intussuception, and discusses the benefits and risks of the fast-track introduction of Rotarix in Latin America, and particularly in Mexico.

Rotavirus strain surveillance in Latin America: a review of the last nine years

BACKGROUND

Latin America will likely be the first area in the developing world where rotavirus vaccine will be introduced into the routine childhood immunization schedule. In anticipation of that goal, we reviewed the distribution of group A rotavirus genotypes in Latin America to understand the diversity of strains to be targeted by vaccines and to identify novel strains that may pose challenges for vaccines.

METHODS

We reviewed studies characterizing rotavirus strains in Latin America (published in English since 1995) that used molecular methods to type genes encoding the G and P outer capsid proteins, VP7 and VP4, and that reported data on >50 specimens.

RESULTS

Fifteen studies from 5 countries met our criteria. In total, 1989 samples were characterized; 12% (233) were mixed rotavirus infections with more than 1 strain, and 20% (402) were not fully typable. Of the remaining 1354 samples that were fully typed, 83% represented the 4 common strains: P[8],G1 (40%); P[4],G2 (30%); P[8],G3 (6%); P[8],G4 (7%). The unusual strains provide interesting insights into virus evolution: some strains (G5) were regionally common; the emerging G9 strains were widely distributed; many animal-human reassortants were present; and some common serotypes (G3 and G4) were of animal origin. Also an unusual G12 serotype was recently detected in Argentina.

CONCLUSIONS

The common rotavirus serotypes should remain the prime targets for vaccine development. However, the changing profile of rare strains, animal-human reassortants and nontypable strains suggest that rotavirus is constantly evolving. Laboratory surveillance is needed to monitor rotavirus strains now in circulation and to detect those that might escape the immunity induced by vaccines or represent vaccine strains entering the environment.

Prevalence and genetic diversity of human astroviruses in Mexican children with symptomatic and asymptomatic infections

The prevalence and type diversity of human astroviruses (HAstV) in children with symptomatic and asymptomatic infections were determined in five localities of Mexico. HAstV were detected in 4.6 (24 of 522) and 2.6% (11 of 428) of children with and without diarrhea, respectively. Genotyping of the detected strains showed that at least seven (types 1 to 4 and 6 to 8) of the eight known HAstV types circulated in Mexico between October 1994 and March 1995. HAstV types 1 and 3 were the most prevalent in children with diarrhea, although they were not found in all localities studied. HAstV type 8 was found in Mexico City, Monterrey, and Mérida; in the last it was as prevalent (40%) as type 1 viruses, indicating that this astrovirus type is more common than previously recognized. A correlation between the HAstV infecting type and the presence or absence of diarrheic symptoms was not observed. Enteric adenoviruses were also studied, and they were found to be present in 2.3 (12 of 522) and 1.4% (6 of 428) of symptomatic and asymptomatic children, respectively.

Prediction of tyrosine sulfation sites in animal viruses

Post-translational modification of proteins by tyrosine sulfation enhances the affinity of extracellular ligand-receptor interactions important in the immune response and other biological processes in animals. For example, sulfated tyrosines in polyomavirus and varicella-zoster virus may help modulate host cell recognition and facilitate viral attachment and entry. Using a Position-Specific-Scoring-Matrix with an accuracy of 96.43%, we analyzed the possibility of tyrosine sulfation in all 1517 animal viruses available in the Swiss-Prot database. From a total of 97,729 tyrosines, we predicted 5091 sulfated tyrosine sites from 1024 viruses. Our site predictions in hemagglutinin of influenza A, VP4 of rotavirus, and US28 of cytomegalovirus strongly suggest an important link between tyrosine sulfation and viral disease mechanisms. In each of these three viral proteins, we observed highly conserved amino acid sequences surrounding predicted sulfated tyrosine sites. Tyrosine sulfation appears to be much more common in animal viruses than is currently recognized.