Do helminths cause epilepsy? The case of Onchocerca volvulus

The Bidirectional Relationship between Sleep and Immunity against Infections

Sleep is considered an important modulator of the immune response. Thus, a lack of sleep can weaken immunity, increasing organism susceptibility to infection. For instance, shorter sleep durations are associated with a rise in suffering from the common cold. The function of sleep in altering immune responses must be determined to understand how sleep deprivation increases the susceptibility to viral, bacterial, and parasitic infections. There are several explanations for greater susceptibility to infections after reduced sleep, such as impaired mitogenic proliferation of lymphocytes, decreased HLA-DR expression, the upregulation of CD14+, and variations in CD4+ and CD8+ T lymphocytes, which have been observed during partial sleep deprivation. Also, steroid hormones, in addition to regulating sexual behavior, influence sleep. Thus, we hypothesize that sleep and the immune-endocrine system have a bidirectional relationship in governing various physiological processes, including immunity to infections. This review discusses the evidence on the bidirectional effects of the immune response against viral, bacterial, and parasitic infections on sleep patterns and how the lack of sleep affects the immune response against such agents. Because sleep is essential in the maintenance of homeostasis, these situations must be adapted to elicit changes in sleep patterns and other physiological parameters during the immune response to infections to which the organism is continuously exposed.

Neurologic manifestations of the neglected tropical diseases

BACKGROUND

The World Health Organization has identified 17 neglected tropical diseases (NTDs) that disproportionately affect the world's poorest populations. The neurologic aspects of many of these NTDs have received relatively little attention.

METHODS

A review was performed in PubMed (MedLine) for each NTD by disease name, name of its causative organism, and neurology, neurosurgery, neurologist, brain, spinal cord, peripheral nerve, muscle, nervous system, encephalitis, meningitis, encephalopathy, stroke, neuropathy, and myopathy (1968-Sept. 2013). The Oxford Center for Evidence-based Medicine guidelines were used to determine the level of evidence of neurological involvement and treatment based on the reports identified.

RESULTS

Neurologic manifestations were reported for all NTDs except yaws. Neurologic involvement was described in systematic reviews for four NTDs (Chagas disease, echinococcosis, rabies, cysticercosis) (levels 2a-3a), retrospective cohort studies for six (dengue, human African trypanosomiasis, leishmaniasis, leprosy, onchocerciasis, schistosomiasis) (levels 2b-3b), case series for one (foodborne trematodiasis) (level 4), and case reports for five (Buruli ulcer, dracunculiasis, filariasis, soil-transmitted helminthes, and trachoma). Level 1 evidence for treatment of neurologic manifestations of NTDs was found for human African trypanosomiasis, leprosy, and cysticercosis and level 2 evidence exists for treatment of neurologic involvement in Chagas disease. For the remaining NTDs, treatment of neurologic complications is described in case series and case reports only.

CONCLUSIONS

Neurologic manifestations of NTDs cause significant morbidity and mortality, although limited evidence exists on how best to treat these neurologic complications. Increased awareness of neurologic manifestations of the NTDs can increase their early identification and treatment, contributing to ongoing elimination and eradication campaigns.