Influenza virus infections among outpatients seeking health care at selected hospitals in Morogoro, Mbeya and Zanzibar, Tanzania
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Date
2020
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Publisher
Sokoine University of Agriculture
Abstract
Respiratory infections cause significant morbidity and mortality worldwide and are the
second leading causes of death in Tanzania. Several studies involving national sentinel
surveillance for influenza and epidemiology of influenza have been conducted in
Tanzania. However, there is dearth in the information on the aetiology of respiratory
diseases. This study screened for influenza viruses in subject with influenza-like illnesses
in selected areas of Tanzania. A total of 735 subjects were recruited at hospitals in
Morogoro, Mbeya and Zanzibar and the collected sample were screened for influenza
viruses using reverse transcription polymerase chain reaction (RT-PCR). Out of the tested
samples, 13% (93/735) were positive for influenza virus. Influenza A accounted for 56%
(52/93) of the detected viruses. Majority of positive cases (19/93; 20%) were from
individuals <9 years and 20 to 35 years old categories. There was a significant difference
in the proportion of influenza positive sample by month (χ2=67.9 p<0.05). Two peaks of
infection were observed from March to May and from November to January. Four
representative influenza isolates were sequenced and genetically characterized. The
BLAST search showed that A/Tanzania/BMH1674/2019 isolate from Zanzibar had
99.86% nucleotide identity with Texas/109/2019 strain from Texas in United States. All
of the three influenza B viruses from Zanzibar and Morogoro were 100% identical and
belong to the influenza B victoria lineage. This study have revealed that influenza A virus
was the most prevalent in 2019 and most of the isolates in our study are not independent
evolution variants, as they shared high nucleotide similarity with characterized reference
strains from the neighbouring countries and other part of the world.
Description
Masters Thesis
Keywords
Influenza, Virus, Infections, Health care, Morogoro