Browsing by Author "Mpabalwani E"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Characterization of human respiratory syncytial virus in children with severe acute respiratory infection before and during the COVID-19 pandemic.
    (2024-Jun) Simusika P; Okamoto M; Dapat C; Muleya W; Malisheni M; Azam S; Imamura T; Saito M; Mwape I; Mpabalwani E; Monze M; Oshitani H; Tohoku University Graduate School of Medicine, Department of Virology, Sendai, Japan.; Center for Infectious Disease Research in Zambia, Lusaka, Zambia.; University Teaching Hospitals, Pathology and Microbiology Department, Virology Laboratory, Lusaka, Zambia.; University of Zambia, School of Veterinary Medicine, Department of Biomedical Sciences, Lusaka, Zambia.; University of Zambia, School of Medicine, Department of Pediatrics and Child Health, Lusaka, Zambia.; Levy Mwanawasa Medical University, Institute of Basic and Biomedical Sciences ,Lusaka, Zambia.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)
    OBJECTIVES: Annual outbreaks of human respiratory syncytial virus (HRSV) are caused by newly introduced and locally persistent strains. During the COVID-19 pandemic, global and local circulation of HRSV significantly decreased. This study was conducted to characterize HRSV in 2018-2022 and to analyze the impact of COVID-19 on the evolution of HRSV. DESIGN/METHODS: Combined oropharyngeal and nasopharyngeal swabs were collected from children hospitalized with severe acute respiratory infection at two hospitals in Zambia. The second hypervariable region of the attachment gene G was targeted for phylogenetic analysis. RESULTS: Of 3113 specimens, 504 (16.2%) were positive for HRSV, of which 131 (26.0%) and 66 (13.1%) were identified as HRSVA and HRSVB, respectively. In early 2021, an increase in HRSV was detected, caused by multiple distinct clades of HRSVA and HRSVB. Some were newly introduced, whereas others resulted from local persistence. CONCLUSIONS: This study provides insights into the evolution of HRSV, driven by global and local circulation. The COVID-19 pandemic had a temporal impact on the evolution pattern of HRSV. Understanding the evolution of HRSV is vital for developing strategies for its control.
  • Thumbnail Image
    Item
    Rotavirus breakthrough infections responsible for gastroenteritis in vaccinated infants who presented with acute diarrhoea at University Teaching Hospitals, Children's Hospital in 2016, in Lusaka Zambia.
    (2021) Simwaka J; Seheri M; Mulundu G; Kaonga P; Mwenda JM; Chilengi R; Mpabalwani E; Munsaka S; Department of Virology, Diarrhoea Pathogens Research Unit and WHO AFRO Rotavirus Regional Reference Laboratory, South African Medical Research Council, Sefako Makgatho Health Sciences University, Pretoria, South Africa.; Center for Infectious Disease Research in Zambia, Lusaka, Zambia.; Department of Biomedical Sciences, School of Health Sciences, University of Zambia, Lusaka, Zambia.; Department of Pathology and Microbiology, School of Medicine, University of Zambia, Lusaka, Zambia.; Department of Internal Medicine, University Teaching Hospital, Tropical Gastroenterology and Nutrition Group, Lusaka, Zambia.; Department of Paediatric and Child Health, School of Medicine, University of Zambia, Lusaka, Zambia.; Department of Epidemiology and Biostatistics, School of Public Health, University of Zambia, Lusaka, Zambia.; World Health Organization Regional Office for Africa (WHO/AFRO), Brazzaville, Congo.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)
    BACKGROUND: In Zambia, before rotavirus vaccine introduction, the virus accounted for about 10 million episodes of diarrhoea, 63 000 hospitalisations and 15 000 deaths in 2015, making diarrhoea the third leading cause of death after pneumonia and malaria. In Zambia, despite the introduction of the vaccine acute diarrhoea due to rotaviruses has continued to affect children aged five years and below. This study aimed to characterise the rotavirus genotypes which were responsible for diarrhoeal infections in vaccinated infants aged 2 to 12 months and to determine the relationship between rotavirus strains and the severity of diarrhoea in 2016. METHODS: Stool samples from infants aged 2 to 12 months who presented to the hospital with acute diarrhoea of three or more episodes in 24 hours were tested for group A rotavirus. All positive specimens that had enough sample were genotyped using reverse transcriptase Polymerase Chain Reaction (RT-PCR). A 20-point Vesikari clinical score between 1-5 was considered as mild, 6-10 as moderate and greater or equal to 11 as severe. RESULTS: A total of 424 stool specimens were tested of which 153 (36%, 95% CI 31.5% to 40.9%) were positive for VP6 rotavirus antigen. The age-specific rotavirus infections decreased significantly (p = 0.041) from 2-4 months, 32.0% (49/118) followed by a 38.8% (70/181) infection rate in the 5-8 months' category and subsequently dropped in the infants aged 9-12 months with a positivity rate of 27.2%. 38.5% of infants who received a single dose, 34.5% of those who received a complete dose and 45.2% (19/42) of the unvaccinated tested positive for rotavirus. The predominant rotavirus genotypes included G2P[6] 36%, G1P[8] 32%, mixed infections 19%, G2P[4] 6%, G1P[6] 4% and G9P[6] 3%. DISCUSSION AND CONCLUSION: Results suggest breakthrough infection of heterotypic strains (G2P[6] (36%), homotypic, G1P[8] (32%) and mixed infections (19%) raises concerns about the effects of the vaccination on the rotavirus diversity, considering the selective pressure that rotavirus vaccines could exert on viral populations. This data indicates that the rotavirus vaccine has generally reduced the severity of diarrhoea despite the detection of the virus strains.