Hepatitis E Virus Infections

Abstract

According to the World Health Organization, approximately 20 million people worldwide are infected annually with the hepatitis E virus (HEV). There are 4 main genotypes of HEV. Genotype 1 and genotype 2 are common in developing countries and are transmitted by contaminated water from a fecal-oral route. Genotype 3 and genotype 4 are common in developed countries and can lead to occasional transmission to humans by undercooked meat. Hepatitis E virus 1 and HEV3 can lead to fulminant hepatitis, and HEV3 can lead to chronic hepatitis and cirrhosis in immunocompromised patients. The majority of patients with HEV infection are asymptomatic and usually have spontaneous viral clearance without treatment. However, infection in immunocompromised individuals can lead to chronic HEV infection. Both acute and chronic HEV infections can have extrahepatic manifestations. No specific treatment is required for acute HEV infection, no treatment has been approved in chronic infection and no HEV vaccine has been approved by the (United States) Food and Drug Administration. This review focuses on the molecular virology (HEV life cycle, genotypes, model systems, zoonosis), pathogenesis, clinical manifestation, and treatment of chronic HEV infection, especially in immunocompromised patients, to provide clinicians a better understanding of the global distribution of these infections and the significant effect they can have on immunocompromised patients.

JWST MIRI/Medium Resolution Spectrograph (MRS) Observations and Spectral Models of the Underluminous Type Ia Supernova 2022xkq

“…SN 2022xkq is located near the edge of a weak spiral arm, 49 91 W and 38 63 S of the center of its host galaxy (see Figure 1 in Pearson et al 2024). Underluminous SNe Ia are typically found in older stellar populations, and thus more likely to occur in elliptical galaxies (Branch et al 1996;Hamuy et al 1996;Howell 2001;Sullivan et al 2010;Ashall et al 2016a;Nugent et al 2023); although old stellar populations can also be found in late-type spirals such as NGC 1784. Interestingly, the underluminous SN 1999by was also discovered in a late-type spiral (Howell 2001;Garnavich et al 2004), and shows some properties similar to those of SN 2022xkq (Pearson et al 2024).…”

Strong Carbon Features and a Red Early Color in the Underluminous Type Ia SN 2022xkq

“…As shown in Figure 1, 55 SN 2022xkq is located in NGC 1784, a barred spiral SB(r)c galaxy (de Vaucouleurs et al 1991;Erwin & Debattista 2013) and SN 2022xkq is the first recorded SN in the galaxy. Underluminous SNe Ia preferentially explode in older galaxy populations and are most likely to be found in elliptical and occasionally in earlytype spiral galaxies (Hamuy et al 2000;Howell 2001;Gallagher et al 2005;Sullivan et al 2006;Li et al 2011;Nugent et al 2023). However, late-type spiral galaxies also possess old stellar populations, and while underluminous SNe Ia in late-type hosts are uncommon, there have been a few.…”