Volatile biomarkers of symptomatic and asymptomatic malaria infection in humans

Abstract

SignificanceMalaria elimination efforts are hindered by the prevalence of asymptomatic infections, which frequently go undetected and untreated. Consequently, there is a pressing need for improved diagnostic screening methods. Based on extensive collections of skin odors from human populations in Kenya, we report broad and consistent effects of malaria infection on human volatile emissions. Furthermore, we found that predictive models based on machine learning algorithms reliably determined infection status based on volatile biomarkers and, critically, identified asymptomatic infections with 100% sensitivity, even in the case of low-level infections not detectable by microscopy. These findings suggest that volatile biomarkers have significant potential for the development of robust, noninvasive screening methods for detecting symptomatic and asymptomatic malaria infections under field conditions.

Endogenous and microbial volatile organic compounds in cutaneous health and disease

“…Environmental factors and personal habits can also influence skin volatile composition, including level of physical activity, personal hygiene, and cosmetic or fragrance usage [9]. Monitoring skin volatiles offers a non-invasive route towards probing pathophysiological status and monitoring therapy, and research in this area to date has primarily focused on internal or systemic disease states for which consistent data has emerged on clinically important skin volatiles, including diabetes [17], hepatic disease [18] and malaria [19].…”

Can Plasmodium’s tricks for enhancing its transmission be turned against the parasite? New hopes for vector control

“…Ten volatiles including ethyl-cyclohexane, ethyl-benzene, m-xylene or p-xylene, o-xylene, propylcyclohexane, 1-ethyl-3-methylbenzene, decane, nonanal, and two unidentified compounds were released at significantly higher amounts in asymptomatic compared to uninfected individuals. In symptomatic individuals, amounts of six compounds, namely, 2,4-dimethylhept-1-ene, 1-ethyl-3-methylbenzene, 1,2,4-trimethylbenzene, decane, s(-)-limonene, and 2-ethylhexan-1-ol were significantly higher compared to those in uninfected individuals (Figure 2) [31]. These studies highlighted that the mature gametocyte (sexual stage of the parasite in human blood) could have been the key contributor to the VOCs [50], chemical codes which communicate between mosquito and parasite to enhance the efficiency of parasite transmission (Figure 2).…”

“…Human malaria parasites alter the probing and persistence behavior of mosquitoes, resulting in increased transmission [28]. There is also evidence that parasites and their metabolites affect both mosquito and human host physiology and behavior to increase the probability of transmission [11,21,[29][30][31][32][33]. In rodent and bird malaria model systems, infected hosts have been found to be more attractive to mosquitoes [30,34].…”

“…The discovery of parasite metabolites (e.g. HMBPP) signaling points to a highly evolved 'trick' by the plasmodium spp., a chemical beacon guiding the anophelines not only to the rare host actually carrying parasites (as in most endemic areas globally, i.e., <2% prevalence), but also to sites on that host tissue bearing parasites for consumption [11,30,31]. These effects observed at miniscule concentrations (picomolar), suggesting an obligate dependency upon parasite signaling to improve the odds of mosquito infection.…”

Ontogenetic changes in wild chagasic bugs (Dipetalogaster maximus): exploring morphological adaptations in pre-adult and adult stages

“…Despite such importance, most studies of Triatominae biology have been concentrated in a handful of species, and attention to the knowledge of animals from natural populations is currently scarce. Recent research in several vector transmitting neglected diseases, including Triatominae bugs, have demonstrated that basic knowledge about vectors' biology and zoonosis helps to find potential solutions to minimize transmission risk (De Moraes et al, 2018;Rojas-de Arias et al, 2017), and phenotypic traits can indirectly provide ecological information to understand vector-parasite ecology (Nattero et al, 2017). For example, Miura et al (2006) found in a trematode-snail host system that infected snails were markedly larger and exhibited different shell morphology than non-infected individuals.…”