METHODOLOGY: A systematic literature search was conducted on PubMed, Cochrane library, World Health Organization database-Index Medicus for South-East Asia Region (WHO-IMSEAR), and Google Scholar databases. The search period was from 1st January 1990 until 12th May 2022. The prevalence of HAIs and subgroups were calculated using MetaXL software.
RESULTS: The database search retrieved 3879 non-duplicate articles. After applying exclusion criteria, 31 articles with a total number of 47666 subjects were included and a total of 7658 cases of HAIs were recorded. The overall prevalence of HAIs in Southeast Asia was 21.6 % (95% CI: 15.5 - 29.1%) with heterogeneity statistics of I2 = 100%. Indonesia had the highest prevalence rate of 30.4% whereas Singapore had the lowest prevalence rate at 8.4%.
CONCLUSIONS: This study revealed that the overall prevalence of HAIs was relatively high and the prevalence rate of each country was associated with socioeconomic status. Measures should be taken to examine and control the rates of HAIs in countries with high HAI prevalence.
METHODS: Genomic DNA of Indonesian black fly samples were extracted and sequenced, producing 86 COI sequences in total. Two hundred four COI sequences, including 118 GenBank sequences, were analysed. Maximum likelihood (ML) and Bayesian inference (BI) trees were constructed and species delimitation analyses, including ASAP, GMYC and single PTP, were performed to determine whether the species of Indonesian black flies could be delineated. Intra- and interspecific genetic distances were also calculated and the efficacy of COI sequences for species identification was tested.
RESULTS: The DNA barcodes successfully distinguished most morphologically distinct species (> 80% of sampled taxa). Nonetheless, high maximum intraspecific distances (3.32-13.94%) in 11 species suggested cryptic diversity. Notably, populations of the common taxa Simulium (Gomphostilbia) cheongi, S. (Gomphostilbia) sheilae, S. (Nevermannia) feuerborni and S. (Simulium) tani in the islands of Indonesia were genetically distinct from those on the Southeast Asian mainland (Malaysia and Thailand). Integrated morphological, cytogenetic and nuclear DNA studies are warranted to clarify the taxonomic status of these more complex taxa.
CONCLUSIONS: The findings showed that COI barcoding is a promising taxonomic tool for Indonesian black flies. The DNA barcodes will aid in correct identification and genetic study of Indonesian black flies, which will be helpful in the control and management of potential vector species.