Small circular single stranded DNA viral genomes in unexplained cases of human encephalitis, diarrhea, and in untreated sewage

Viruses with small circular ssDNA genomes encoding a replication initiator protein can infect a wide range of eukaryotic organisms ranging from mammals to fungi. The genomes of two such viruses, a cyclovirus (CyCV-SL) and gemycircularvirus (GemyCV-SL) were detected by deep sequencing of the cerebrospinal fluids of Sri Lankan patients with unexplained encephalitis. One and three out of 201 CSF samples (1.5%) from unexplained encephalitis patients tested by PCR were CyCV-SL and GemyCV-SL DNA positive respectively. Nucleotide similarity searches of pre-existing metagenomics datasets revealed closely related genomes in feces from unexplained cases of diarrhea from Nicaragua and Brazil and in untreated sewage from Nepal. Whether the tropism of the cyclovirus and gemycircularvirus reported here include humans or other cellular sources in or on the human body remains to be determined

Case report of hypnic headache: a rare headache disorder with nocturnal symptoms

Abstract Background Headache is one of the commonest complaints reported to physicians worldwide. Yet, arriving at the proper diagnosis can be a challenge in many patients. Although most headaches belong to common categories of migraine and tension-type headache, which are diagnosed and managed relatively easily, several uncommon headache disorders can lead to delays in diagnosis. Certain medications are more efficacious than others in managing these headache disorders, hence establishing the correct diagnosis is of paramount importance. Case presentation An 86-year-old female presented with chronic daily headache of 1 year duration. Her headaches were exclusively nocturnal and woke her up daily around midnight. Clinical examination was unremarkable. All basic investigations were normal. Subsequent gadolinium enhanced Magnetic Resonance Imaging (MRI) brain did not show any significant pathology. There was no satisfactory response to paracetamol, diclofenac sodium, mefenamic acid, tramadol, flunarizine and sodium valproate. Indomethacin was started with the provisional diagnosis of hypnic headache. There was absolute response by day 3 of indomethacin. She remains headache free on low dose indomethacin maintenance at 1 year after the diagnosis. Conclusion Better understanding of uncommon headache syndromes can help in early diagnosis and appropriate treatment. Hypnic headache should be considered in the differential diagnosis of chronic daily headaches, especially when nocturnal and occurs during sleep

Guillain–Barre syndrome of acute motor axonal neuropathy (AMAN) type associated with herpes zoster: a case report

Abstract Guillain Barre syndrome (GBS) following Varicella zoster is a rare presentation and has only been reported in a few cases around the world. Of the reported cases, the type of GBS is not specified in the majority, and where specified is of the acute inflammatory demyelinating polyradiculoneuropathy (AIDP) type. We report a case of acute motor axonal neuropathy (AMAN) type GBS following herpes zoster in a 27-year-old male who presented with bilateral lower limb weakness and left sided lower motor neuron type facial nerve palsy a week after herpes zoster infection

Some human studies with neurophysiological findings in snake neurotoxicity.

<p>(CMAP, compound muscle action potential; RNS, repetitive nerve stimulation; EMG, electromyography; SNAP, sensory nerve action potential).</p

Summary table of some key studies with descriptions of neurotoxicity.

<p>(N/A – not available).</p

Bilateral ptosis and facial weakness in neurotoxic envenoming.

<p>Sri Lankan patient with bilateral ptosis and facial weakness following a Krait (<i>Bunagrus caeruleus</i>) bite. (Photograph courtesy of Prof. S. A. M. Kularatne, University of Peradeniya, Sri Lanka. The purpose of the photograph has been explained to the patient, and consent obtained for potential publication.)</p

Summary of some key animal studies with individual snake neurotoxins.

<p>Summary of some key animal studies with individual snake neurotoxins.</p

Respiratory paralysis in neurotoxic envenoming.

<p>Sri Lankan patient with severe neurotoxicity and respiratory paralysis being ventilated following a cobra (<i>Naja naja</i>) bite. (Photograph courtesy of Prof. S. A. M. Kularatne, University of Peradeniya, Sri Lanka. The purpose of the photograph has been explained to the patient, and consent obtained for potential publication.)</p

Sites of action of snake neurotoxins and other substances on the neuromuscular junction.

<p>Schematic representation of the neuromuscular junction showing different sites of action of snake neurotoxins, other toxins, and pharmacological substances, and sites of involvement in disease states (examples indicated where relevant). 1. <b>Synaptic vesicular proteins</b>: <i><u>Snake toxins</u></i>: beta-bungarotoxin (<i>Bungarus</i> spp.), taipoxin (<i>O. scutellatus</i>); <i><u>Other toxins</u></i>: botulinum toxin, tetanus neurotoxin. 2. <b>Voltage-gated calcium channel</b>: <i><u>Snake toxins</u></i><u>:</u> calciseptine (<i>Dendroaspis</i> spp.), beta- bungaratoxin (<i>Bungarus</i> spp.); <i><u>Other toxins</u></i>: omega-conotoxin (marine snail, <i>Conus</i> spp.); <i><u>Disease states</u></i>: Lambert-Eaton myaesthenic syndrome. 3. <b>Pre-synaptic membrane</b>: <i><u>Snake toxins</u></i>: phospholipase A2 toxins. 4. <b>Pre-synaptic ACh receptor</b>: <i><u>Snake toxins</u></i>: candoxin (<i>Bungarus candidus</i>); <i><u>Other toxins</u></i>: curare; <i><u>Pharmacological substances</u></i><u>:</u> non-depolarising blocking drugs (atracurium). 5. <b>Voltage-gated potassium channels</b>: <i><u>Snake toxins</u></i>: dendrotoxins (<i>Dendroaspis</i> spp.); <i><u>Disease states</u></i>: neuromyotonia, Isaacs' syndrome; <i><u>Pharmacological substances</u></i>: magnesium sulphate, aminoglycosides. 6. <b>Acetylcholine</b>: Lysis by exogenous acetylcholinesterase in <i><u>snake venom</u></i>: cobra venom (<i>Naja</i> spp.). 7. <b>Acetylcholinesterase</b>: Inhibitors of endogenous AChE in <i><u>snake venom</u></i>: fasiculins (<i>Dendroaspis</i> spp.). 8. <b>Post-synaptic ACh receptors</b>: <i><u>Snake toxins</u></i>: alpha-bungaratoxin (<i>Bungarus</i> spp.), candoxin (<i>B. candidus</i>), azemiopsin (<i>A. feae</i>), waglerin (<i>T. wagleri</i> ); <i><u>Other toxins</u></i>: alpha-conotoxin (marine snail, <i>Conus</i> spp.); <i><u>Disease states</u></i>: myasthenia gravis; <i><u>Pharmacological substances</u></i>: depolarising blocking agents (e.g., succinylcholine), non-depolarising blocking drugs (e.g., atracurium). 9. <b>Voltage-gated sodium channels</b>: <i><u>Snake toxins</u></i>: crotamine (<i>Crotalus</i> spp.); <i><u>Other toxins</u></i>: pompilidotoxin (wasps), delta-conotoxin (<i>Conus</i> spp.), tetradotoxin (pufferfish).</p

Some examples of toxin diversity in snake venom.

<p>Some examples of toxin diversity in snake venom.</p