Increase in rotavirus prevalence with the emergence of genotype G9P[8] in replacement of genotype G12P[6] in Sabah, Malaysia.

Rotaviruses are major causative agents of acute diarrhea in children under 5 years of age in Malaysia. However, a rotavirus vaccine has not been included in the national vaccination program. To date, only two studies have been carried out in the state of Sabah, Malaysia, although children in this state are at risk of diarrheal diseases. Previous studies showed that 16%-17% of cases of diarrhea were caused by rotaviruses and that equine-like G3 rotavirus strains are predominant. Because the prevalence of rotaviruses and their genotype distribution vary over time, this study was conducted at four government healthcare facilities from September 2019 through February 2020. Our study revealed that the proportion of rotavirus diarrhea increased significantly to 37.2% (51/137) after the emergence of the G9P[8] genotype in replacement of the G12P[8] genotype. Although equine-like G3P[8] strains remain the predominant rotaviruses circulating among children, the Sabahan G9P[8] strain belonged to lineage VI and was phylogenetically related to strains from other countries. A comparison of the Sabahan G9 strains with the G9 vaccine strains used in the RotaSiil and Rotavac vaccines revealed several mismatches in neutralizing epitopes, indicating that these vaccines might not be effective in Sabahan children. However, a vaccine trial may be necessary to understand the precise effects of vaccination.

Mumps outbreak in university students: first detection of mumps virus genotype F in Borneo.

BACKGROUND: In October 2016, a mumps outbreak occurred among the students living in the on-campus dormitory of a public university located in Kota Kinabalu, Sabah, Malaysia. This study aimed to investigate the outbreak and identify the genotype of the mumps virus (MuV) strain that was involved in the outbreak. MAIN BODY: During the outbreak, one 21-year-old and four 20-year-old males staying in the same dormitory building were reported to have developed symptoms of mumps. Of these, two students were available during the investigation for sample collection to detect MuV by reverse transcription polymerase chain reaction (RT-PCR) of the 639-bp fragment encompassing the entire small hydrophobic (SH) gene. Nucleotide sequencing of the amplicon and phylogenetic analysis using the neighbor-joining method was performed to determine the MuV genotype. Of the two buccal swab samples, one was positive for MuV. The MuV strain in this sample belonged to genotype F and it was clustered together with genotype F strains from China with 96.84-99.68% nucleotide identity. CONCLUSIONS: Genotype F has limited circulation and is endemic in mainland China. Genotype F strains occasionally reported from other countries were epidemiologically linked to China. This study is the first to report a case of genotype F MuV in Malaysia and no epidemiological link could be established with mainland China. The results provide important information that can assist in strategic planning to improve the prevention and control of mumps infection in Malaysia.

Seroepidemiological survey of the prevalence of Helicobacter pylori infection in Sabah, Malaysia.

Objective: Gastric cancer is an important cause of mortality in Sabah, Malaysia, but the prevalence of Helicobacter pylori infection in this state is unknown. Serology is an important tool for the surveillance of H. pylori infection. The objective of this study was to determine the prevalence of H. pylori infection by serology, and to provide information for policy discussions on H. pylori control programmes in Sabah. Methods: This cross-sectional study analysed serum samples collected from blood donors in a hospital in Kota Kinabalu, Sabah. H. pylori antibody concentration was measured using a commercially available kit. Results: The prevalence of H. pylori was 28.4% (204/718), and the infection rate was highest in subjects aged 30-39 years. Men were more likely to be infected than women. The H. pylori infection rate was highest among those of Kadazan (19.1%) ethnicity, followed by Dusun (15.7%), Bajau (14.7%) and Rungus (10.8%). Binary logistic regression analysis indicated that Chinese (P=0.026) and Malay (P=0.035) ethnicities were protective against H. pylori infection compared with other ethnicities. Conclusions: The seropositivity rate of H. pylori in this study was similar to the overall seropositivity rate in Malaysia; however, Chinese and Malay ethnicities were found to be protective against H. pylori infection.

A 1-year cross-sectional study on the predominance of influenza among hospitalized children in a tropical area, Kota Kinabalu, Sabah.

BACKGROUND: Children are at higher risk of influenza virus infection, and it is difficult to diagnose. They are also responsible for the transmission of influenza because of their longer viral shedding compared to adults. In Malaysia, studies on influenza in children are scarce, and as a result, policy decisions cannot be formulated to control the infection. Hence, the objective of this study is to determine the prevalence and epidemiological characteristics of influenza among children with upper respiratory symptoms in the Sabah state of Malaysia. METHODS: A cross-sectional study with a simple random sampling was conducted among children with upper respiratory symptoms in Sabah from 1 March 2019 to 29 February 2020. Patients admitted to a pediatric ward of Sabah Women and Children's Hospital who presented with a fever >38 °C and cough within 48 h of admission were enrolled in this study. A nasopharyngeal swab was taken, and influenza was diagnosed by lateral flow test. Clinical features of influenza-positive children were compared with children whose results were negative. RESULTS: A total of 323 nasopharyngeal samples were collected, and 66 (20.4%) of them were positive for influenza. Fifty-six (85%) were infected by influenza A whereas ten (15%) were by influenza B virus. Higher temperature (aOR 2.03, 95% CI 1.296-3.181), less activity (aOR 2.07, 95% CI 1.158-3.693), and seizure (aOR 4.2, 95% CI 1.614-10.978) on admission were significant risk factors associated with influenza in children. Meteorology parameters such as humidity and rainfall amount were statistically significant at 95% CI [1.133 (1.024-1.255)] and 95% CI [0.946 (0.907-0.986)]. CONCLUSION: The prevalence of influenza was high among children with upper respiratory symptoms, and they were infected predominantly with the influenza A virus. Children presented with seizures, less activity, and fever were the significant risk factors for influenza. Influenza vaccination should be prioritized as preventive measures for children.

Emergence of equine-like G3 strains as the dominant rotavirus among children under five with diarrhea in Sabah, Malaysia during 2018-2019.

Rotavirus infection is a dilemma for developing countries, including Malaysia. Although commercial rotavirus vaccines are available, these are not included in Malaysia's national immunization program. A scarcity of data about rotavirus genotype distribution could be partially to blame for this policy decision, because there are no data for rotavirus genotype distribution in Malaysia over the past 20 years. From January 2018 to March 2019, we conducted a study to elucidate the rotavirus burden and genotype distribution in the Kota Kinabalu and Kunak districts of the state of Sabah. Stool specimens were collected from children under 5 years of age, and rotavirus antigen in these samples was detected using commercially available kit. Electropherotypes were determined by polyacrylamide gel electrophoresis of genomic RNA. G and P genotypes were determined by RT-PCR using type specific primers. The nucleotide sequence of the amplicons was determined by Sanger sequencing and phylogenetic analysis was performed by neighbor-joining method. Rotavirus was identified in 43 (15.1%) children with watery diarrhea. The male:female ratio (1.9:1) of the rotavirus-infected children clearly showed that it affected predominantly boys, and children 12-23 months of age. The genotypes identified were G3P[8] (74% n = 31), followed by G1P[8] (14% n = 6), G12P[6](7% n = 3), G8P[8](3% n = 1), and GxP[8] (3% n = 1). The predominant rotavirus circulating among the children was the equine-like G3P[8] (59.5% n = 25) with a short electropherotype. Eleven electropherotypes were identified among 34 strains, indicating substantial diversity among the circulating strains. The circulating genotypes were also phylogenetically diverse and related to strains from several different countries. The antigenic epitopes present on VP7 and VP4 of Sabahan G3 and equine-like G3 differed considerably from that of the RotaTeq vaccine strain. Our results also indicate that considerable genetic exchange is occurring in Sabahan strains. Sabah is home to a number of different ethnic groups, some of which culturally are in close contact with animals, which might contribute to the evolution of diverse rotavirus strains. Sabah is also a popular tourist destination, and a large number of tourists from different countries possibly contributes to the diversity of circulating rotavirus genotypes. Considering all these factors which are contributing rotavirus genotype diversity, continuous surveillance of rotavirus strains is of utmost importance to monitor the pre- and post-vaccination efficacy of rotavirus vaccines in Sabah.

High proportion of norovirus infection and predominance of GII.3 [P12] genotype among the children younger than 5 in Sabah, Malaysian Borneo.

Globally, norovirus (NoV) has become one of the important causes of acute gastroenteritis (AGE) in children. It is responsible for death of children younger than 5 years in developing countries. Although there is limited information and the rate of child mortality caused by diarrhea is low in Malaysia, the burden of diarrhea is high, especially in Sabah. NoV GI, GII and GIV genogroups are known to infect humans, and GII.4 is the predominant genotype distributed worldwide. Better understanding of the etiology of NoV will help to inform policies for prevention and control. The aim of this study was to determine the burden and genotype distribution of NoV in children younger than 5 years with AGE who attended health-care facilities in Sabah, Malaysia. Diarrhea stool samples were collected from 299 children with AGE and NoV was detected by amplifying the capsid and RNA-dependent RNA polymerase gene and reverse transcription-polymerase chain reaction (RT-PCR) analysis. Nucleotide sequencing of the amplicons was used for genotypes and phylogenetic analyses . NoV-positive stool samples were found in 17.7% (53/299) among which 13/53 (24.5%), 38/53 (71.7%), and 2/53 (3.8%) identified as NoV GI, GII and combination of GI and GII, respectively. The most common genotypes were GII.3 [P12] (80%) followed by GII.6 [P7] (13.3%), and GII.17 [P17] (6.7%). In the phylogenetic tree, all Sabahan NoV samples were shown to share ancestry with their respective genotype from predominantly East Asian countries and to some extent Australia and Europe. However, the Sabahan strains formed independent clusters with significant bootstrap values, indicating a clonal spread after the strains had entered Sabah.