RESULTS: The ternary nanocomposite containing conducting polymer polypyrrole, cobalt oxide, and silver nanoparticles showed potent antimicrobial effects against these pathogens. The antibacterial assay showed that PPy-Co3O4-AgNPs exhibited significant bactericidal activity against neuropathogenic E. coli K1 at only 8 μg/mL as compared to individual components of the nanocomposite, whereas a 70 % inhibition of A. castellanii viability was observed at 50 μg/mL. Moreover, PPy-Co3O4-AgNPs were found to have minimal cytotoxicity against human keratinocytes HaCaT cells in vitro even at higher concentration (50 μg/mL), and also reduced the microbes-mediated cytopathogenicity against host cells.
CONCLUSION: These results demonstrate that PPy-Co3O4-AgNPs hold promise in the development of novel antimicrobial nanomaterials for biomedical applications.
KEY POINTS: •Synthesis of polypyrrole-cobalt oxide-silver (PPy-Co3O4-AgNPs) nanocomposite. •Antimicrobial activity of nanocomposite. •PPy-Co3O4-AgNPs hold promise for biomedical applications.
RESULTS: Apart from several named species of malaria parasites, long-tailed macaques were found to be potentially infected with novel species of Plasmodium, namely one we refer to as "P. inui-like." This group of parasites bifurcated into two monophyletic clades indicating the presence of two distinct sub-populations. Further analyses, which relied on the assumption of strict co-phylogeny between hosts and parasites, estimated a population expansion event of between 150,000 to 250,000 years before present of one of these sub-populations that preceded that of the expansion of P. knowlesi. Furthermore, both sub-populations were found to have diverged from a common ancestor of P. inui approximately 1.5 million years ago. In addition, the phylogenetic analyses also demonstrated that long-tailed macaques are new hosts for P. simiovale.
CONCLUSIONS: Malaria infections of long-tailed macaques of Sarawak, Malaysian Borneo are complex and include a novel species of Plasmodium that is phylogenetically distinct from P. inui. These macaques are new natural hosts of P. simiovale, a species previously described only in toque monkeys (Macaca sinica) in Sri Lanka. The results suggest that ecological factors could affect the evolution of malaria parasites.
METHODS: The protocol of the systematic review was registered at PROSPERO with approval ID CRD42020203046. Three databases (Web of Science, Scopus, and MEDLINE) were searched for studies reporting the prevalence of P. cynomolgi infections in Southeast Asian countries between 1946 and 2020. The pooled prevalence or pooled proportion of P. cynomolgi parasitemia in humans, mosquitoes, and macaques was estimated using a random-effects model. Differences in the clinical characteristics of P. cynomolgi infections were also estimated using a random-effects model and presented as pooled odds ratios (ORs) or mean differences (MDs) with 95% confidence intervals (CIs).
RESULTS: Thirteen studies reporting on the prevalence of naturally acquired P. cynomolgi in humans (3 studies, 21 cases), mosquitoes (3 studies, 28 cases), and macaques (7 studies, 334 cases) were included. The results demonstrated that the pooled proportion of naturally acquired P. cynomolgi in humans was 1% (95% CI, 0.1%, I2, 0%), while the pooled proportion of P. cynomolgi infecting mosquitoes was 18% (95% CI, 10-26%, I2, 32.7%). The pooled prevalence of naturally acquired P. cynomolgi in macaques was 47% (95% CI, 27-67%, I2, 98.3%). Most of the cases of naturally acquired P. cynomolgi in humans were reported in Cambodia (62%) and Malaysia (38%), while cases of P. cynomolgi in macaques were reported in Malaysia (35.4%), Singapore (23.2%), Indonesia (17.3%), Philippines (8.5%), Laos (7.93%), and Cambodia (7.65%). Cases of P. cynomolgi in mosquitoes were reported in Vietnam (76.9%) and Malaysia (23.1%).
CONCLUSIONS: This study demonstrated the occurrence of naturally acquired P. cynomolgi infection in humans, mosquitoes, and macaques. Further studies of P. cynomolgi in asymptomatic human cases in areas where vectors and natural hosts are endemic are extensively needed if human infections with P. cynomolgi do become public health problems.