Description
O8.1Although endemic for malaria and with previously reported cases of low-density malaria infections (LDIs), data on the molecular epidemiology of malaria in Guinea-Bissau are scarce. To estimate the frequency of LDIs not detected by optical microscopy (OM) in the Nacional Malaria Indicator Survey carried out in 2017 (MIS 2017), a subset of 597 dried whole-blood samples (DBS) on filter paper, almost 7% of blood samples collected and analysed by OM in the MIS 2017, was analysed by nested PCR targeting the 18S rRNA gene (nPCR). Genotyping of HBB, the coding gene for the haemoglobin beta-subunit, was used as a control for the DNA extractions, and the mutant allele HbS, was screened in all samples. Data were analysed using IBM SPSS Statistics version 26. The nPCR confirmed the presence of Plasmodium falciparum parasites in 80 of 98 samples identified previously by OM (patent infections) and identified three of them as co-infections with Plasmodium malariae, not previously detected by OM. Among the 499-OM negative samples, the nPCR identified 20 samples as positive for P. falciparum (LDIs). The 80 patent infections were observed in individuals up to 24 years of age, while the 20 LDIs were mainly found in individuals aged 15 years of age and older (p<0.001, by Fisher Exact test). Most of the infected individuals lived in the high malaria transmission health regions, did not report symptoms and 30% of LDIs were found in the same household of a patent infection. We did not find association between the HBB genotype and patent (n=80) or LDIs (n=20), however, 18 P. falciparum infections, only detected by OM, were associated with the allele HbS (p<0.001, by Fisher Exact test). Data suggest the presence of genomic distinct P. falciparum parasites and the benefits of genomic surveillance to scale up community case management interventions in Guinea-Bissau.
| Period | 16 Nov 2023 |
|---|---|
| Event title | 16th International Conference on Molecular Epidemiology and Evolutionary Genetics of Infectious Diseases |
| Event type | Conference |
| Location | Dresden, GermanyShow on map |
| Degree of Recognition | International |