Malaria, immunity and mental disorders: A plausible relationship?
EBioMedicine; 40 (), 2019
Ano de publicação: 2019
Malaria is the most common and dangerous parasitic disease, being
responsible every year for nearly half a million deaths, and an estimated
219 million clinical cases, globally [1]. The devastating short-term effects that an acute malarial infection can have on any given individual
have been historically well characterized, and there are also abundant
data on the subacute and chronic sequelae derived from severe malarial
episodes, which are understandable in the context of the sudden and
profound insult that such an aggressive infection may have in the central nervous system and other key organs [2]. However, much scarcer
information exists regarding other more subtle or prolonged deleterious effects of malarial infection and disease on well-being, beyond its
acute phase, particularly in regard to common mental disorders
(CMD) and neuro-psychiatric health.
In this recent article of EBioMedicine [3] Rachel Jenkins and colleagues explore the three-way relationship between malaria, mental
disorders and immunity in a representative sample of adults randomly
selected from the Kombewa Health and Demographic Surveillance system running in Kisumu, a highly malaria-endemic county located in
Western Kenya [4]. To do so, authors applied a myriad of validated
structured questionnaires designed to assess mental health and collected blood samples of the studied individuals to confirm malaria
parasitaemia and test for common markers of immune function (CD4/
CD3 ratio, CD4 counts, IL-1β, IL-6, IL-8, and IL-10, TNF-β, TNF-α). Although no associations were found between malaria and psychotic
symptoms, their results confirm a statistically significant association between malaria and CMD (OR 1.7, p = 0.014), a heterogeneous group of
distress states which typically manifest with anxiety, depressive and
unexplained somatic symptoms. Their results also hint at the potential
mediating role that the cytokine TNF-α may play in this association.
The association between mental health and non-communicable diseases has been widely studied [5], with evidence of inflammation significantly contributing to the pathogenesis of major psychiatric disorders
(including depression [6] or schizophrenia [7], among others), and the
inflammasome -a multiprotein oligomer responsible for the activation
of inflammatory responses- proposed as a central mediator [8]. Conversely, the association between mental health and communicable