Hepatitis A and Hepatitis E: Clinical and Epidemiological Features, Diagnosis, Treatment, and Prevention

Hepatitis A and E are both ancient diseases but have only been properly recognized as being caused by distinct pathogens in modern times. Despite significantly different genomic structures, both viruses employ remarkably similar strategies to avoid host detection and increase environmental transmission. There are millions of cases of acute viral hepatitis due to hepatitis A virus (HAV) and hepatitis E virus (HEV) each year, resulting in tens of thousands of deaths. The presentations can be clinically indistinguishable, but each virus also has a range of less common but more specific phenotypes. The epidemiology of HAV is complex, and is shifting in countries that are making improvements to public health and sanitation. HEV presents a significant public health challenge in resource-limited settings but has historically been incorrectly regarded as having little clinical relevance in industrialized countries.

Hepatitis E: an underestimated emerging threat

Hepatitis E virus (HEV) is the most common cause of viral hepatitis in the world. It is estimated that millions of people are infected every year, resulting in tens of thousands of deaths. However, these estimates do not include industrialized regions and are based on studies which employ assays now known to have inferior sensitivity. As such, this is likely to represent a massive underestimate of the true global burden of disease. In the developing world, HEV causes large outbreaks and presents a significant public-health problem. Until recently HEV was thought to be uncommon in industrialized countries, and of little relevance to clinicians in these settings. We now know that this is incorrect, and that HEV is actually very common in developed regions. HEV has proved difficult to study in vitro, with reliable models only recently becoming available. Our understanding of the lifecycle of HEV is therefore incomplete. Routes of transmission vary by genotype and location: endemic regions experience large waterborne epidemics, while sporadic cases in industrialized regions are zoonotic infections likely spread via the food chain. Both acute and chronic infection has been observed, and a wide range of extrahepatic manifestations have been reported. This includes neurological, haematological and renal conditions. As the complete clinical phenotype of HEV infection is yet to be characterized, a large proportion of cases go unrecognized or misdiagnosed. In many cases HEV infection does not feature in the differential diagnosis due to a lack of knowledge and awareness of the disease amongst clinicians. In combination, these factors have contributed to an underestimation of the threat posed by HEV. Improvements are required in terms of recognition and diagnosis of HEV infection if we are to understand the natural history of the disease, improve management and reduce the burden of disease around the world.

Hepatitis E virus infection and acute non-traumatic neurological injury: A prospective multicentre study

BACKGROUND & AIMS

Hepatitis E virus (HEV) has been associated with a number of neurological syndromes, but causality has not yet been established. The aim of this study was to explore the relationship between HEV and neurological illness by prospective HEV testing of patients presenting with acute non-traumatic neurological injury.

METHODS

Four hundred and sixty-four consecutive patients presenting to hospital with acute non-traumatic neurological illnesses were tested for HEV by serology and PCR from four centres in the UK, France and the Netherlands.

RESULTS

Eleven of 464 patients (2.4%) had evidence of current/recent HEV infection. Seven had HEV RNA identified in serum and four were diagnosed serologically. Neurological cases in which HEV infection was found included neuralgic amyotrophy (n=3, all PCR positive); cerebral ischemia or infarction (n=4); seizure (n=2); encephalitis (n=1); and an acute combined facial and vestibular neuropathy (n=1). None of these cases were clinically jaundiced and median ALT at presentation was 24IU/L (range 8-145). Cases of HEV-associated neuralgic amyotrophy were found in each of the participating countries: all were middle-aged males with bilateral involvement of the brachial plexus.

CONCLUSIONS

In this cohort of patients with non-traumatic neurological injury, 2.4% had evidence of HEV infection. Symptoms of hepatitis were mild or absent and no patients were jaundiced. The cases of HEV-associated neuralgic amyotrophy had similarities with other HEV-associated cases described in a large retrospective study. This observation supports a causal relationship between HEV and neuralgic amyotrophy. To further understand the relevance of HEV infection in patients with acute neurological illnesses, case-control studies are warranted. Lay summary: Hepatitis E virus (HEV), as its name suggests, is a hepatotropic virus, i.e. it causes damage to the liver (hepatitis). Our findings show that HEV can also be associated with a range of injury to the nervous system.

Acute high-caffeine exposure increases autophagic flux and reduces protein synthesis in C2C12 skeletal myotubes

Caffeine is a highly catabolic dietary stimulant. High caffeine concentrations (1-10 mM) have previously been shown to inhibit protein synthesis and increase protein degradation in various mammalian cell lines. The purpose of this study was to examine the effect of short-term caffeine exposure on cell signaling pathways that regulate protein metabolism in mammalian skeletal muscle cells. Fully differentiated C2C12 skeletal myotubes either received vehicle (DMSO) or 5 mM caffeine for 6 h. Our analysis revealed that caffeine promoted a 40% increase in autolysosome formation and a 25% increase in autophagic flux. In contrast, caffeine treatment did not significantly increase the expression of the skeletal muscle specific ubiquitin ligases MAFbx and MuRF1 or 20S proteasome activity. Caffeine treatment significantly reduced mTORC1 signaling, total protein synthesis and myotube diameter in a CaMKKβ/AMPK-dependent manner. Further, caffeine promoted a CaMKII-dependent increase in myostatin mRNA expression that did not significantly contribute to the caffeine-dependent reduction in protein synthesis. Our results indicate that short-term caffeine exposure significantly reduced skeletal myotube diameter by increasing autophagic flux and promoting a CaMKKβ/AMPK-dependent reduction in protein synthesis.

Investigation of liver dysfunction: who should we test for hepatitis E?

AIM

Hepatitis E virus (HEV) is endemic in developed countries, but unrecognized infection is common. Many national guidelines now recommend HEV testing in patients with acute hepatitis irrespective of travel history. The biochemical definition of 'hepatitis' that best predicts HEV infection has not been established. This study aimed to determine parameters of liver biochemistry that should prompt testing for acute HEV.

METHODS

This was a retrospective study of serial liver function tests (LFTs) in cases of acute HEV (n=74) and three comparator groups: common bile duct stones (CBD, n=87), drug-induced liver injury (DILI, n=69) and patients testing negative for HEV (n=530). To identify the most discriminating parameters, LFTs from HEV cases, CBD and DILI were compared. Optimal LFT cutoffs for HEV testing were determined from HEV true positives and HEV true negatives using receiver operating characteristic curve analysis.

RESULTS

Compared with CBD and DILI, HEV cases had a significantly higher maximum alanine aminotransferase (ALT) (P<0.001) and ALT/alkaline phosphatase (ALKP) ratio (P<0.001). For HEV cases/patients testing negative for HEV, area under receiver operating characteristic curve was 0.805 for ALT (P<0.001) and 0.749 for the ALT/ALKP ratio (P<0.001). Using an ALT of at least 300 IU/l to prompt HEV testing has a sensitivity of 98.6% and a specificity of 30.3% compared with an ALT/ALKP ratio higher than or equal to 2 (sensitivity 100%, specificity 9.4%).

CONCLUSION

Patients with ALT higher than or equal to 300 IU/l should be tested for HEV. This is simple, detects nearly all cases and requires fewer samples to be tested than an ALT/ALKP ratio higher than or equal to 2. Where clinically indicated, patients with an ALT less than 300 IU/l should also be tested, particularly if HEV-associated neurological injury is suspected.

Hepatitis E virus: Western Cape, South Africa

AIM

To conduct a prospective assessment of anti-hepatitis E virus (HEV) IgG seroprevalence in the Western Cape Province of South Africa in conjunction with evaluating risk factors for exposure.

METHODS

Consenting participants attending clinics and wards of Groote Schuur, Red Cross Children’s Hospital and their affiliated teaching hospitals in Cape Town, South Africa, were sampled. Healthy adults attending blood donor clinics were also recruited. Patients with known liver disease were excluded and all major ethnic/race groups were included to broadly represent local demographics. Relevant demographic data was captured at the time of sampling using an interviewer-administered confidential questionnaire. Human immunodeficiency virus (HIV) status was self-disclosed. HEV IgG testing was performed using the Wantai^® assay.

RESULTS

HEV is endemic in the region with a seroprevalence of 27.9% (n = 324/1161) 95%CI: 25.3%-30.5% (21.9% when age-adjusted) with no significant differences between ethnic groups or HIV status. Seroprevalence in children is low but rapidly increases in early adulthood. With univariate analysis, age ≥ 30 years old, pork and bacon/ham consumption suggested risk. In the multivariate analysis, the highest risk factor for HEV IgG seropositivity (OR = 7.679, 95%CI: 5.38-10.96, P < 0.001) was being 30 years or older followed by pork consumption (OR = 2.052, 95%CI: 1.39-3.03, P < 0.001). A recent clinical case demonstrates that HEV genotype 3 may be currently circulating in the Western Cape.

CONCLUSION

Hepatitis E seroprevalence was considerably higher than previously thought suggesting that hepatitis E warrants consideration in any patient presenting with an unexplained hepatitis in the Western Cape, irrespective of travel history, age or ethnicity.

Hepatitis E Virus: Time to Change the Textbooks

Until recently, hepatitis E virus (HEV) was thought not to occur in developed countries. It is now clear that locally acquired HEV is common in such settings. HEV infection acquired in these areas differs from that in developing countries in a number of important aspects: it is caused by genotype 3 (and 4 in China and Japan), it mainly affects middle-aged/elderly males and it is zoonotic with a porcine primary host. Pig herds worldwide are infected with HEV genotype 3 and HEV has been found in the human food chain in a number of developed countries. However, the route of transmission is not fully understood, since most cases are not obviously associated with pigs/pig products. HEV can be transmitted by blood transfusion and surprisingly high numbers of asymptomatic blood donors are viremic at the time of donation: Germany 1:1,200, Netherlands 1:2,671, England 1:2,848. Our understanding of the clinical phenotype of HEV infection in humans has undergone a sea-change in recent years. Previously, HEV was thought to cause only acute self-limiting hepatitis. However, HEV may cause persistent disease in the immunocompromised. Patients with chronic HEV infection have no symptoms, but some develop rapidly progressive liver cirrhosis. The full clinical spectrum of HEV is still emerging. HEV has important extra-hepatic manifestations, which deserve further investigation. For example, HEV can cause a wide range of neurological illness. In particular, very recent data suggest that Guillain-Barré syndrome and neuralgic amyotrophy are associated with locally acquired HEV in approximately 5 and 10% of the cases, respectively.

Maternal and fetal implications of anticonvulsive therapy during pregnancy

A team approach with close communication among the obstetrician, neurologist, pediatrician, and patient will result in an uneventful pregnancy in most epileptic women. Women should be counseled regarding the greater than 90% likelihood of a favorable outcome. Maternal and neonatal outcome can be optimized by carefully evaluating the clinical necessity of anticonvulsant medications preconceptionally. One can then prescribe an appropriate choice based on seizure type and history of response, with a goal of achieving monotherapy at the lowest effective dose. Nonpharmacologic intervention, such as avoiding high levels of stress and sleep deprivation, will also help the patient to remain seizure-free during the pregnancy. In addition, folic acid and vitamin K can help optimize neonatal outcome. In short, most epileptic women will experience a normal pregnancy, labor, and delivery of a healthy baby and can breastfeed if desired. Although the incidence of congenital malformations with any anticonvulsant is increased, the actual incidence remains relatively low. Despite the shortcomings and risks of anticonvulsants, adequate therapy is clearly preferable to uncontrolled seizure activity. Women should be encouraged to optimize their anticonvulsive therapy prior to pregnancy, usually resulting in adequate therapy throughout the pregnancy and postpartum, with a happy and healthy outcome for mother and infant.

Management of the pregnant woman who sustains severe brain damage

Management of the severely brain-injured pregnant patient is a considerable challenge to the ethicist as well as to the obstetrician; to the neurologist; and, of course, to any family on which such a tragedy might fall. Certainly, it is ethical in some situations to continue somatic support of a lethally injured gravida for the benefit of the fetus. It is equally ethical in certain situations to withdraw support of a severely neurologically compromised patient regardless of an ongoing pregnancy. Physicians caring for such a patient must clarify the maternal diagnosis, the fetal gestational age, and the prognosis of both maternal and fetal patients. The appropriate proxy decision maker for the patient incapable of giving informed consent must be identified, and extensive effort must be expended to educate and empathize with that individual as well as any other involved family members. Application of the basic principles of medical ethics can then provide a framework within which the above information can be used to develop and evolve an appropriate clinical management plan for the specific situation at hand.

Diagnostic aids for the detection of urine in the equine ejaculate

An experiment was conducted to evaluate three commercially available test kits, the Azostix, Multistix and Uric-acid test, for the detection of urine in the equine ejaculate. Azostix, which tests for urea nitrogen, consistently detected urine in the equine ejaculate. Urine contamination was evident when a color change occurred in the reagent pad, going from yellow to green after 10 sec of exposure. The sensitivity of Azostix to urea nitrogen in contaminated samples was 39 mg/dl. The Multistix test kit also successfully detected urine in semen. In the Multistix nitrite pad the color changed from yellow to organge after 3.5 min of exposure to urine-contaminated semen. The Uricacid test kit did not accurately detect urine-contaminated samples. It constantly elicited false positive results in all the control trials. The results of this study show that Azostix and Multistix are cost effective ($1.25 per analysis) and accurate diagnostic aids for detecting urine in the stallion ejaculate.

Central effects of thyrotropin-releasing hormone and arginine vasopressin on intraocular pressure in rabbits

Administration of either thyrotropin-releasing hormone (TRH) or arginine vasopressin (a-VP) into the rabbit third ventricle elevated intraocular pressure (IOP). IOP was increased 3.6 mmHg 45 min after TRH (10 ng/0.1 ml) administration and increased 6.4 mmHg 45 min following delivery of a-VP (5 micrograms/0.1 ml). Outflow facility and episcleral venous pressure were not altered by either agent. Estimated aqueous humor flow 45 min after third ventricle administration was increased 66% after TRH and 91% after a-VP delivery. Posterior chamber aqueous humor ascorbate was reduced 60 min after TRH administration. Pretreatment with either systemic or topical atropine prevented the TRH or a-VP induced increase in IOP. Body temperature (BT), which was unaltered after TRH administration, was elevated by third ventricle delivery of a-VP. The a-VP induced increase in BT was blocked by systemic pretreatment with either indomethacin or atropine.

Palinspastic Restoration Suggesting Late Paleozoic North Atlantic Rifting

Palinspastic restoration of sinistral wrench faults in Britain and of dextral wrenches in Canada, starting with the palinspastic pre-continental-drift map, implies the possibility of as much as 424 kilometers of rifting between Newfoundland and Ireland. The wrench-faulting and postulated resultant rifting are of Devonian and Carboniferous age.

Superconductivity and the d -Shell

The various isotope effects on the superconducting transition temperature of Mo(2)B and W(2)B have been measured. Together with resistivity data they indicate that the d-shell forms a highly stable electron configuration for molybdenum and tungsten. This leads to an understanding of high superconducting transition temperatures.