Human pegivirus-1 infection in kidney transplant recipients: A single-center experience.

Kidney transplantation is the treatment of choice for patients with end-stage renal disease. In the posttransplant period, the induced immunosuppression leads to an increased risk of developing infectious diseases, a leading cause of death after kidney transplantation. Human pegivirus-1 (HPgV-1) is considered a nonpathogenic human virus and is highly frequent in individuals parenterally exposed, however, its impact on kidney transplantation outcome is poorly understood. Given the scarcity of epidemiological data for this infection on organ recipients in Brazil, we conducted a study in a single center for kidney transplantation in Rio de Janeiro, aiming to determine HPgV-1 prevalence and genotypic distribution. Serum samples from 61 renal recipients, followed up for the first year after transplantation, were evaluated for viral RNA and genotypes were determined by sequencing of the 5'-untranslated region. HPgV-1 RNA was detected in 36.1% (22/61) of patients. Genotype 2 was the most commonly found (80.9%), followed by genotypes 3 (9.5%), 1, and 5, in 4.8% each. Statistical comparisons did not reveal any significant impact of HPgV-1 in patient outcome. Further epidemiologic studies are needed to understand if immunosuppression may interfere in HPgV-1 persistence rates and if viremia might impact graft dysfunction rates in kidney recipients.

Hepatotropic viruses (hepatitis A, B, C, D and E) in a rural Brazilian population: prevalence, genotypes, risk factors and vaccination.

BACKGROUND: People living in settlement projects represent an emergent rural population in Brazil. Data on their health is scarce and there are no data on viral hepatitis in this population. This study investigated the epidemiology of viral hepatitis A-E in residents of settlement projects in central Brazil. METHODS: During 2011 and 2012, 923 people living in rural settlements in central Brazil were interviewed and tested to estimate the prevalence of exposure to viral hepatitis A-E, to identify the circulating hepatitis B virus (HBV)/hepatitis C virus (HCV) genotypes and risk factors for HBV exposure and to evaluate adherence to the hepatitis B vaccination series. RESULTS: Overall, 85.9, 3.9, 0.4 and 17.3% of individuals showed evidence of exposure to hepatitis A virus (HAV), hepatitis E virus, HCV and HBV, respectively. Among HBV-DNA positive samples (n=8), subgenotypes A1 (n=3) and A2 (n=1) and genotype D/subgenotype D3 (n=4) were identified. Hepatitis D virus superinfection was detected in 0/16 HBsAg-positive participants. A total of 229 individuals showed serological evidence of HBV vaccination. In total, 442 settlers were eligible for vaccination, but only 150 individuals completed the vaccine series. All anti-HCV-positive samples (n=4) were also HCV-RNA positive and identified as subtype 1a. CONCLUSIONS: The intermediate endemicity of HAV, the higher prevalence of HBV exposure compared with urban areas and the low compliance with HBV vaccination requires preventive measures focused on rural populations, emphasizing the need for HAV and HBV vaccination.

Hepatitis B virus infection among oncohematologic disease patients in Central Brazil: prevalence, risk factors and immunization

ABSTRACT Introduction: Carriers of oncohematological diseases are at high risk for hepatitis B virus (HBV) infection. Objective and method: To investigate the epidemiology of HBV infection in Goiânia, Central Brazil, 322 individuals with oncohematological diseases (leukemias, Hodgkin lymphoma and non-Hodgkin lymphoma) were interviewed and blood samples were collected for the detection of serological markers of HBV-DNA by polymerase chain reaction (PCR). Medical records of participants were also reviewed. Results: Non-Hodgkin's lymphomas (n = 99) and chronic myeloid leukemia (n = 108) were the most frequent oncohematological diseases. The overall prevalence of HBV was 13.97% (45/322). Of the total participants, 8.69% (28/322) presented isolated positivity for anti-HBs, suggesting low vaccine coverage. HBV-DNA was detected in 25% (1/4) of HBsAg positive samples and in 25% (3/12) of anti-HBc isolated, suggesting HBV occult infection. All samples were identified as subgenotype A1. Entries in patient records and the findings of this investigation suggest anti-HBc seroconversion during oncologic treatment. Age 50 years or over and use of a central catheter during therapy were associated with HBV exposure. Conclusion: The low frequency of hepatitis B immunized individuals, detection of HBV DNA in HBsAg negative samples, and the suggestion of HBV exposure during treatment evidenced the potential for health-related viral dissemination in people with oncohematological diseases in our region, reinforcing the importance of serological monitoring, vaccination against hepatitis B, and adoption of strict infection control measures in these individuals.

Hepatitis B virus infection among oncohematologic disease patients in Central Brazil: prevalence, risk factors and immunization.

INTRODUCTION: Carriers of oncohematological diseases are at high risk for hepatitis B virus (HBV) infection. OBJECTIVE AND METHOD: To investigate the epidemiology of HBV infection in Goiânia, Central Brazil, 322 individuals with oncohematological diseases (leukemias, Hodgkin lymphoma and non-Hodgkin lymphoma) were interviewed and blood samples were collected for the detection of serological markers of HBV-DNA by polymerase chain reaction (PCR). Medical records of participants were also reviewed. RESULTS: Non-Hodgkin's lymphomas (n=99) and chronic myeloid leukemia (n=108) were the most frequent oncohematological diseases. The overall prevalence of HBV was 13.97% (45/322). Of the total participants, 8.69% (28/322) presented isolated positivity for anti-HBs, suggesting low vaccine coverage. HBV-DNA was detected in 25% (1/4) of HBsAg positive samples and in 25% (3/12) of anti-HBc isolated, suggesting HBV occult infection. All samples were identified as subgenotype A1. Entries in patient records and the findings of this investigation suggest anti-HBc seroconversion during oncologic treatment. Age 50 years or over and use of a central catheter during therapy were associated with HBV exposure. CONCLUSION: The low frequency of hepatitis B immunized individuals, detection of HBV DNA in HBsAg negative samples, and the suggestion of HBV exposure during treatment evidenced the potential for health-related viral dissemination in people with oncohematological diseases in our region, reinforcing the importance of serological monitoring, vaccination against hepatitis B, and adoption of strict infection control measures in these individuals.

Hepatitis B virus genotypes A1, A2 and E in Cape Verde: Unequal distribution through the islands and association with human flows.

Hepatitis B virus (HBV) diversity has not been previously studied in Cape Verde. The archipelago was discovered in 1460 by Portuguese explorers, who brought African slaves to colonise the islands. In this study, we investigated the HBV characteristics from 183 HBsAg-positive Cape Verdean individuals. Phylogenetic analysis of the pre-S/S region and the full-length genomes revealed 54 isolates with HBV/A1 (57%), 21 with HBV/A2 (22%), 19 with HBV/E (20%), and one with HBV/D (1%). HBV genotypes and subgenotypes were unequally distributed through the islands. In São Vicente, the main northern island, most isolates (84%) belonged to the African-originated HBV/A1, with the remaining isolates belonging to HBV/A2, which is prevalent in Europe. Interestingly, the HBV/A1 isolates from São Vicente were closely related to Brazilian sequences into the Asian-American clade, which suggests the dissemination of common African ancestors through slave trade. In contrast, in Santiago and nearby southern islands, where a recent influx from different populations circulates, a higher diversity of HBV was observed: HBV/A1 (40%); HBV/E (32%); HBV/A2 (28%); and HBV/D (1%). HBV/E is a recent genotype disseminated in Africa that was absent in the era of the slave trade. African and European human flows at different times of the history may explain the HBV diversity in Cape Verde. The possible origin and specifics of each HBV genotype circulating in Cape Verde are discussed.

HIV-1, HBV, HCV, HTLV, HPV-16/18, and Treponema pallidum infections in a sample of Brazilian men who have sex with men.

BACKGROUND: Men who have sex with men (MSM) are more vulnerable to blood-borne infections and/or sexually-transmitted infections (STI). This study was conducted to estimate the prevalences of mono and co-infections of HIV-1 and other blood-borne/STIs in a sample of MSM in Campinas, Brazil. METHODS: Responding Driven Sampling (RDS) was used for recruitment of MSM. Serum samples collected from 558 MSM were analyzed for the presence of serological markers for HIV-1, HBV, HCV, HTLV, HPV-16/18, and T. pallidum infections. RESULTS: The highest prevalences of infection in serum samples were found for HPV-16 and 18 (31.9% and 20.3%, respectively). Approximately 8% of the study population showed infection with HIV-1, and within that group, 27.5% had recently become infected with HIV-1. HBV infection and syphilis were detected in 11.4% and 10% of the study population, respectively, and the rates of HTLV and HCV infection were 1.5% and 1%, respectively. With the exception of HTLV, all other studied infections were usually found as co-infections rather then mono-infections. The rates of co-infection for HCV, HPV-18, and HIV-1 were the highest among the studied infections (100%, 83%, and 85%, respectively). Interestingly, HTLV infection was usually found as a mono-infection in the study group, whereas HCV was found only as a co-infection. CONCLUSIONS: The present findings highlight the need to educate the MSM population concerning their risk for STIs infections and methods of prevention. Campaigns to encourage vaccination against HBV and HPV could decrease the rates of these infections in MSM.

Analysis of complete nucleotide sequences of Angolan hepatitis B virus isolates reveals the existence of a separate lineage within genotype E.

Hepatitis B virus genotype E (HBV/E) is highly prevalent in Western Africa. In this work, 30 HBV/E isolates from HBsAg positive Angolans (staff and visitors of a private hospital in Luanda) were genetically characterized: 16 of them were completely sequenced and the pre-S/S sequences of the remaining 14 were determined. A high proportion (12/30, 40%) of subjects tested positive for both HBsAg and anti-HBs markers. Deduced amino acid sequences revealed the existence of specific substitutions and deletions in the B- and T-cell epitopes of the surface antigen (pre-S1- and pre-S2 regions) of the virus isolates derived from 8/12 individuals with concurrent HBsAg/anti-HBs. Phylogenetic analysis performed with 231 HBV/E full-length sequences, including 16 from this study, showed that all isolates from Angola, Namibia and the Democratic Republic of Congo (n = 28) clustered in a separate lineage, divergent from the HBV/E isolates from nine other African countries, namely Cameroon, Central African Republic, Côte d'Ivoire, Ghana, Guinea, Madagascar, Niger, Nigeria and Sudan, with a Bayesian posterior probability of 1. Five specific mutations, namely small S protein T57I, polymerase Q177H, G245W and M612L, and X protein V30L, were observed in 79-96% of the isolates of the separate lineage, compared to a frequency of 0-12% among the other HBV/E African isolates.

Molecular epidemiology of adenovirus conjunctivitis in Rio de Janeiro, Brazil, between 2004 and 2007.

Viral conjunctivitis is a common, highly contagious disease often caused by adenovirus. We investigate the frequency of adenoviral conjunctivitis in the population of Rio de Janeiro, Brazil, between March 2004 and May 2007 and identified the predominant serotype circulating among this population. Seventy-five ocular swabs were collected from 66 patients with clinical presentation of conjunctivitis. The specimens were analyzed for detection of adenovirus (AdV) by polymerase chain reaction (PCR). The PCR products were further analyzed for virus typing by sequence analysis and/or heteroduplex mobility assay (HMA). Forty-five samples (60%) were positive for AdV of which 21 samples were typed as AdV19 (46.7%), 7 AdV8 (15.5%), 3 AdV31 (6.7%), and one each AdV1, AdV2, AdV3, AdV4 and AdV6. For nine samples the serotype was not determined. AdV19 was the predominant serotype circulating in Rio de Janeiro during the studied period.

Molecular epidemiology of adenovirus conjunctivitis in Rio de Janeiro, Brazil, between 2004 and 2007 / Epidemiologia molecular de adenovírus associados à conjuntivite no Rio de Janeiro, Brasil, no periodo de 2004 a 2007

Viral conjunctivitis is a common, highly contagious disease often caused by adenovirus. We investigate the frequency of adenoviral conjunctivitis in the population of Rio de Janeiro, Brazil, between March 2004 and May 2007 and identified the predominant serotype circulating among this population. Seventy-five ocular swabs were collected from 66 patients with clinical presentation of conjunctivitis. The specimens were analyzed for detection of adenovirus (AdV) by polymerase chain reaction (PCR). The PCR products were further analyzed for virus typing by sequence analysis and/or heteroduplex mobility assay (HMA). Forty-five samples (60%) were positive for AdV of which 21 samples were typed as AdV19 (46.7%), 7 AdV8 (15.5%), 3 AdV31 (6.7%), and one each AdV1, AdV2, AdV3, AdV4 and AdV6. For nine samples the serotype was not determined. AdV19 was the predominant serotype circulating in Rio de Janeiro during the studied period.

A conjuntivite viral é doença ocular comum, altamente contagiosa, frequentemente causada por adenovírus. Neste estudo, investigamos a frequência de conjuntivite por adenovírus na população do Rio de Janeiro, Brasil, entre março de 2004 e maio de 2007, e identificamos o sorotipo predominante circulando nesta população. Setenta e cinco swabs de secreção ocular foram coletados de 66 pacientes com conjuntivite. As amostras foram analisadas para detecção de adenovírus (AdV) por reação em cadeia da polimerase (PCR). Os produtos da PCR foram caracterizados por sequenciamento e/ou ensaio de mobilidade do heteroduplex (Heteroduplex Mobility Assay - HMA) para identificação do sorotipo viral. Quarenta e cinco (60%) amostras foram positivas para AdV das quais 21 foram identificadas como pertencentes ao sorotipo AdV19 (46,7%), sete AdV8 (15,5%), três AdV31 (6,7%), e uma de cada: AdV1, AdV2, AdV3, AdV4 e AdV6. Para nove amostras o sorotipo não pode ser identificado. O AdV 19 foi o sorotipo predominante circulando no Rio de Janeiro durante o período estudado.

Atividade analgésica do extrato da Pectis jangadensis (S. Moore) / Preliminary evaluation of Pectis jangadensis (S. Moore) analgesic activity

A planta Pectis jangadensis, popularmente conhecida como "roxinha", "erva do carregador" ou "coentro da chapada" é utilizada em chás pela população matogrossense, como calmante. Não há estudo na literatura sobre qualquer atividade farmacológica dessa planta. Nosso objetivo foi avaliar atividade analgésica de seu extrato hidro-alcoólico nas doses de 100, 500 e 1000 mg/kg pelos métodos de Contorções induzidas pelo ácido acético e teste da formalina. Os nossos resultados demonstram que não houve diferença significativa entre o grupo controle e os grupos tratados com diferentes doses do extrato tanto em relação ao número de contorções induzidas pelo ácido acético quanto ao tempo de lambedura da pata, na fase 1 e 2, induzida pela formalina. Portanto, pelo menos, por via oral, parece que o extrato hidro-alcoólico da Pectis jangadensis não apresenta atividade analgésica.

"Preliminary evaluation of Pectis jangadensis (S. Moore) analgesic activity's". The plant Pectis jangadensis, popularly known as "roxinha", "erva do carregador" or "coentro da chapada" is used in teas by the matogrossense's people, as a calmative. There isn't any study in the literature about its pharmacologic activity. Our object was to evaluate its extract hidroalcoolic analgesic activity in doses of 100, 500 and 1000 mg/kg by the methods of abdominal writhing induced by acetic acid and the Formalin test. The results show that there wasn't significant difference between the control groups and the groups treated with different doses of the extract in both testes. Therefore, at least by oral, seems that the Pectis jangadensis' hidroalcoolic extract doesn't have analgesic activity.

A unique amino acid substitution, L215Q, in the hepatitis B virus small envelope protein of a genotype F isolate that inhibits secretion of hepatitis B virus subviral particles.

The small (S) envelope protein is the major component of hepatitis B virus surface antigen (HBsAg). Some mutations in the S-HBsAg coding region may cause deficiency in the secretion of both viral and empty subviral particles (SVPs) and lead to accumulation of HBsAg inside the cells. In this study, we identified a unique amino acid substitution (L215Q) in the carboxyl-terminal end of S-HBsAg of an HBV genotype F isolate that provoked an inhibitory effect on secretion of SVPs. HBsAg levels were measured daily by enzyme-linked immunosorbent assay in the medium and cell extracts of HuH7 and CHO cells transiently transfected with plasmids containing wild-type or mutated S-HBsAg gene. Wild-type HBsAg was detectable in both medium and cell extracts of transfected cells. In contrast, extracellular levels of mutant HBsAg were not higher than cut-off values. By immunofluorescence with monoclonal antibody, it was shown that wild-type HBsAg was distributed throughout the cytoplasm, whereas mutant HBsAg was concentrated around the nucleus, suggesting retention in the endoplasmic reticulum. Amino acid substitutions that inhibit HBsAg secretion, such as that characterized in this study (L215Q), should have implications in HBV immunological diagnostics.

Norovirus detection and genotyping for children with gastroenteritis, Brazil.

During 1998-2005, we analyzed stool samples from 289 children in Rio de Janeiro to detect and genotype no-rovirus strains. Previous tests showed all samples to be negative for rotavirus and adenovirus. Of 42 (14.5%) no-rovirus-positive specimens, 20 (47.6%) were identified as genogroup GI and 22 (52.3%) as GII.

Human bocavirus infection in children with gastroenteritis, Brazil.

Human bocavirus (HBoV) was detected in 14 (2%) of 705 fecal specimens from Brazilian children with gastroenteritis. Coinfection with rotavirus, adenovirus, or norovirus was found in 3 (21.4%) HBoV-positive specimens. None of the HBoV-positive patients had respiratory symptoms.

Rotavirus diarrhea in children and adults in a southern city of Brazil in 2003: distribution of G/P types and finding of a rare G12 strain.

Between May and August in 2003, a total of 251 fecal samples were collected from children and adults with diarrhea (5 inpatients and 246 outpatients) at a private hospital in the city of Ponta Grossa, the state of Paraná, Brazil. Group A rotavirus was detected in 71 of 251 (28.3%) specimens: 55 (77.5%) from children under 5 years of age and 16 (22.5%) from individuals aged 6-72 years. All 71 strains exhibited a "long" RNA pattern when analyzed by PAGE. Sixty-one positive samples that yielded enough RNA were submitted to PCR genotyping. The most frequent G/P genotype combination detected was G1P[8] (86.9%; 53/61) followed by G9P[8] (3.3%; 2/61) and G12P[9] (1.6%; 1/61). Rotaviruses with G2, G3, G4, P[4], or P[6] specificity were not detected. For three strains (4.9%) bearing G1 genotype, the VP4 specificity could no be determined, and two specimens (3.3%) remained G/P non-typeable. One rotavirus strain (HC91) bearing G12P[9] genotype with a "long" electropherotype was isolated from an 11-month-old boy with diarrhea for the first time in Brazil. The cell-culture grown HC91 strain was shown to belong to serotype G12 by neutralization.

Rotavirus surveillance in the city of Rio de Janeiro-Brazil during 2000-2004: detection of unusual strains with G8P[4] or G10P[9] specificities.

Rotavirus diarrhea is a potentially life-threatening disease that affects millions of children annually around the world. Because protection against rotavirus disease is thought to be type specific, continuous rotavirus surveillance before and after implementation of a vaccine is still of essential importance. Rotavirus surveillance has been conducted in the city of Rio de Janeiro, Brazil since 1982. In the present study, we report rotavirus surveillance data in Rio de Janeiro city from 2000 to 2004. One hundred twenty nine of 1,568 (8.2%) stool samples, collected from children with acute diarrhea between January 2000 and July 2004 were rotavirus-positive. One hundred twenty eight of the 129 (99.2%) rotavirus-positive samples were genotyped for G and/or P specificity. G1 was the predominant strain (49.6%, 64/129) followed by G9 (30.2%, 39/129), and G4 (17.8%, 23/129); G2 and G3 viruses were not detected. One sample (0.8%) was non-typeable. P genotypes were determined for 124 of the 129 (96%) samples, and P[8] was the predominant genotype (90.6%, 117/129). Genotypes P[4] and P[9] were detected in two (1.6%) samples each; one (0.8%) sample presented P[6] genotype; and five (3.8%) samples were non-typeable. Two samples (1.6%) presented mixed P genotypes (P[6] + P[8]). Two unusual strains were isolated: a G8P[4] strain isolated from a non-hospitalized child with diarrhea and a G10P[9] strain isolated from a hospitalized child with diarrhea.

Predominance of rotavirus genotype G9 during the 1999, 2000, and 2002 seasons among hospitalized children in the city of Salvador, Bahia, Brazil: implications for future vaccine strategies.

Two hundred eight of 648 (32%) diarrheal stool samples collected from hospitalized children under 5 years of age during a 3-year period (1999, 2000, and 2002) in the city of Salvador, in the state of Bahia, Brazil, were rotavirus positive. One hundred sixty-four of 208 (78.8%) rotavirus-positive samples had genotype G9 specificity, predominantly in association with P[8]. Other specificities detected were G1 (12.0%) and G4 (1.4%). Viruses with G2, G3, or P[4] specificity were not detected. Rotavirus genotype G9 predominated during each of the three seasons studied; it represented 89.2% of rotavirus strains detected in 1999, 85.3% in 2000, and 74.5% in 2002. G1 viruses (the globally most common G type) have a unique epidemiological characteristic of maintaining predominance during multiple consecutive rotavirus seasons. We have shown in this study for the first time that the G9 viruses also have a similar epidemiological characteristic, albeit for a shorter period of surveillance. The next generation of rotavirus vaccines will need to provide adequate protection against disease caused by G9 viruses.

Genotyping of enteric adenoviruses by using single-stranded conformation polymorphism analysis and heteroduplex mobility assay.

Single-stranded conformation polymorphism (SSCP) analysis and heteroduplex mobility assays (HMAs) were used to identify and genotype enteric adenoviruses (EAd). The results were compared to those of restriction endonuclease assays, species-specific PCRs, and direct nucleotide sequence analyses. Of the 31 stool samples tested, 15 isolates were identified as EAd and 7 were identified as nonenteric Ad by all methods. An agreement of 100% was found between the SSCP and HMA results.

Surveillance of rotavirus strains in Rio de Janeiro, Brazil, from 1997 to 1999.

One hundred fifty-seven (23%; n = 678) rotavirus-positive stool samples were collected between March 1997 and December 1999 in the cites of Rio de Janeiro and Niterói. Rotaviruses in 143 (91%) samples were genotyped by reverse transcription-PCR for G and/or P specificity. Rotaviruses in the majority of G-P-typeable samples (73.3%; 74 of 101) were identified as having globally common genotypes G1P[8], G2P[4], G3P[8], and G4P[8]. Unusual strains such as G1P[9], G2[P8], G3P[9], and G9P[4] strains were detected in 8.9% (9 of 101) of the samples. Genotypes G9P[8], G9P[6], and a mixture of G9 and other G or P types represented 15.9% (25 of 157) of the isolates. Mixed infections were detected in 25 (15.9%) samples, and rotaviruses in 15 samples (9.6%) were not typed.

VP7 gene polymorphism of serotype G9 rotavirus strains and its impact on G genotype determination by PCR.

Rotaviruses are the single most important etiologic agents of severe diarrhea of infants and young children worldwide. Surveillance of rotavirus serotypes/genotypes (both VP7[G] and VP4[P]) is in progress globally in which polymerase chain reaction (PCR) has been the assay of choice. We investigated polymorphism of the VP7 gene of serotype G9 rotavirus strains and its impact on the determination of VP7 gene genotype by PCR assay. By VP7 gene sequence analysis, we and others have previously shown that the G9 rotavirus strains belong to one of three VP7 gene lineages. By PCR assay using three different sets of commonly used primers specific for G1-4, 8 and 9, 23 Brazilian G9 strains and 5 well-characterized prototype G9 strains which collectively represented all three VP7 gene lineages were typed as: (i) G3; (ii) G4; (iii) G9; (iv) G3 and G9; or (v) G9 and G4 depending on a primer pool employed. This phenomenon appeared to be due to: (i) a VP7 gene lineage-specific polymorphism, more specifically mutation(s) in the primer binding region of the VP7 gene of G9 strain; and (ii) the magnitude of difference in nucleotide homology at respective primer binding site between homotypic (G9) and heterotypic (G3 or G4) primers present in a primer pool employed.

VP7 gene polymorphism of serotype G9 rotavirus strains and its impact on G genotype determination by PCR.

Rotaviruses are the single most important etiologic agents of severe diarrhea of infants and young children worldwide. Surveillance of rotavirus serotypes/genotypes (both VP7[G] and VP4[P]) is in progress globally in which polymerase chain reaction (PCR) has been the assay of choice. We investigated polymorphism of the VP7 gene of serotype G9 rotavirus strains and its impact on the determination of VP7 gene genotype by PCR assay. By VP7 gene sequence analysis, we and others have previously shown that the G9 rotavirus strains belong to one of three VP7 gene lineages. By PCR assay using three different sets of commonly used primers specific for G1-4, 8 and 9, 23 Brazilian G9 strains and 5 well-characterized prototype G9 strains which collectively represented all three VP7 gene lineages were typed as: (i). G3; (ii). G4; (iii). G9; (iv). G3 and G9; or (v). G9 and G4 depending on a primer pool employed. This phenomenon appeared to be due to: (i). a VP7 gene lineage-specific polymorphism, more specifically mutation(s) in the primer binding region of the VP7 gene of G9 strain; and (ii). the magnitude of difference in nucleotide homology at respective primer binding site between homotypic (G9) and heterotypic (G3 or G4) primers present in a primer pool employed.