The Interplay Between Neuroinfections, the Immune System and Neurological Disorders: A Focus on Africa

Abstract

Neurological disorders related to neuroinfections are highly prevalent in Sub-Saharan Africa (SSA), constituting a major cause of disability and economic burden for patients and society. These include epilepsy, dementia, motor neuron diseases, headache disorders, sleep disorders, and peripheral neuropathy. The highest prevalence of human immunodeficiency virus (HIV) is in SSA. Consequently, there is a high prevalence of neurological disorders associated with HIV infection such as HIV-associated neurocognitive disorders, motor disorders, chronic headaches, and peripheral neuropathy in the region. The pathogenesis of these neurological disorders involves the direct role of the virus, some antiretroviral treatments, and the dysregulated immune system. Furthermore, the high prevalence of epilepsy in SSA (mainly due to perinatal causes) is exacerbated by infections such as toxoplasmosis, neurocysticercosis, onchocerciasis, malaria, bacterial meningitis, tuberculosis, and the immune reactions they elicit. Sleep disorders are another common problem in the region and have been associated with infectious diseases such as human African trypanosomiasis and HIV and involve the activation of the immune system. While most headache disorders are due to benign primary headaches, some secondary headaches are caused by infections (meningitis, encephalitis, brain abscess). HIV and neurosyphilis, both common in SSA, can trigger long-standing immune activation in the central nervous system (CNS) potentially resulting in dementia. Despite the progress achieved in preventing diseases from the poliovirus and retroviruses, these microbes may cause motor neuron diseases in SSA. The immune mechanisms involved in these neurological disorders include increased cytokine levels, immune cells infiltration into the CNS, and autoantibodies. This review focuses on the major neurological disorders relevant to Africa and neuroinfections highly prevalent in SSA, describes the interplay between neuroinfections, immune system, neuroinflammation, and neurological disorders, and how understanding this can be exploited for the development of novel diagnostics and therapeutics for improved patient care.

Serum Cytokines Predict Neurological Damage in Genetically Diverse Mouse Models

“…Viruses are abundant, ubiquitous in nature, and may be deleterious to human health. Prior viral infections, including Epstein-Barr virus (EBV) [1,2], Herpes Simplex virus (HSV) [3,4], Human immunodeficiency virus (HIV) [5,6], poliovirus [7,8], Zika virus [9,10], and many others have been associated with subsequent neurological damage [11]. Comorbidities and predisposing genetic risk factors for neurological and immunological dysfunction often vary among individuals in natural populations.…”

Secondary headache disorders in Turkey, the Middle East, Asia, and Africa: A cross-sectional, multicenter study

“…In Sub-Saharan Africa (SSA), secondary headache disorders caused by various infections are prevalent and contribute to a significant burden of disability and economic impact on patients and society (34). Sleep disorders, which are also prevalent in SSA, have been linked to infectious diseases such as human African trypanosomiasis and HIV (35).…”

“…Similarly, a study conducted in Egypt identified meningitis as the second most common cause of secondary headache, following post-traumatic headache (35). In the Middle East and North Africa (MENA) region, other infectious diseases such as tuberculosis, HIV/AIDS, and brucellosis have also been associated with secondary headaches (34). In our current study, we investigated the frequency of headaches attributed to infections according to the ICHD-3 criteria (2).…”

Prevalence of neuroinfectious diseases and outcomes in Africa

“…Finally, there is a need for proper research on various infections affecting the nervous system. Ngarka et al [5] study on neuroinfections in Africa demonstrated the need for a thorough investigation into the risk factors, triggering factors, and mechanisms underlying these infections. This would aid in the development of novel therapeutic approaches for the effective management of these infections [5] .…”