Case Report Associated with Aspergillosis and Hepatitis E Virus Coinfection in Himalayan Griffons

Animal reservoirs for hepatitis E virus within the Paslahepevirus genus

Hepatitis E virus (HEV) is responsible for acute hepatitis in humans. It is a single-stranded, positive-sense RNA virus that belongs to the Hepeviridae family. The majority of concerning HEV genotypes belong to the Paslahepevirus genus and are subsequently divided into eight genotypes. HEV genotypes 1 and 2 exclusively infect humans and primates while genotypes 3 and 4 infect both humans and other mammals. Whereas HEV genotypes 5 and 6 are isolated from wild boars and genotypes 7 and 8 were identified from camels in the United Arab Emirates and China, respectively. HEV mainly spreads from humans to humans via the fecal-oral route. However, some genotypes with the capability of zoonotic transmissions, such as 3 and 4 transmit from animals to humans through feces, direct contact, and ingestion of contaminated meat products. As we further continue to uncover novel HEV strains in various animal species, it is becoming clear that HEV has a broad host range. Therefore, understanding the potential animal reservoirs for this virus will allow for better risk management and risk mitigation of infection with HEV. In this review, we mainly focused on animal reservoirs for the members of the species Paslahepevirus balayani and provided a comprehensive list of the host animals identified to date.

Cross-Species Transmission of Rabbit Hepatitis E Virus to Pigs and Evaluation of the Protection of a Virus-like Particle Vaccine against Rabbit Hepatitis E Virus Infection in Pigs

We investigated the cross-species transmission of rabbit hepatitis E virus (rb HEV) to pigs and evaluated the cross-protection of a swine (sw) HEV-3 virus-like particle (VLP) vaccine against rb HEV infection in pigs. Twelve 4-week-old conventional pigs were divided into negative control (n = 3), positive control (rb HEV-infected, n = 4), and vaccinated (vaccinated and rb HEV-challenged, n = 5) groups. The vaccine was administered at weeks 0 and 2, and viral challenge was conducted at week 4. Serum HEV RNA, anti-HEV antibody, cytokine, and liver enzyme levels were determined. Histopathological lesions were examined in abdominal organs. Viral RNA was detected and increased anti-HEV antibody and alanine aminotransferase (ALT) levels were observed in positive control pigs; liver fibrosis, inflammatory cell infiltration in the lamina propria of the small intestine and shortened small intestine villi were also observed. In vaccinated pigs, anti-HEV antibody and Th1 cytokine level elevations were observed after the second vaccination; viral RNA was not detected, and ALT level elevations were not observed. The results verified the cross-species transmission of rb HEV to pigs and cross-protection of the sw HEV-3 VLP vaccine against rb HEV infection in pigs. This vaccine may be used for cross-protection against HEV infection in other species.

Hepatitis E Virus in Croatia in the "One-Health" Context

Hepatitis E virus (HEV) is the most common cause of viral hepatitis globally. The first human case of autochthonous HEV infection in Croatia was reported in 2012, with the undefined zoonotic transmission of HEV genotype 3. This narrative review comprehensively addresses the current knowledge on the HEV epidemiology in humans and animals in Croatia. Published studies showed the presence of HEV antibodies in different population groups, such as chronic patients, healthcare professionals, voluntary blood donors and professionally exposed and pregnant women. The highest seroprevalence in humans was found in patients on hemodialysis in a study conducted in 2018 (27.9%). Apart from humans, different studies have confirmed the infection in pigs, wild boars and a mouse, indicating the interspecies transmission of HEV due to direct or indirect contact or as a foodborne infection. Continued periodical surveys in humans and animals are needed to identify the possible changes in the epidemiology of HEV infections.

Aspergillosis in Wild Birds

The ubiquitous fungi belonging to the genus Aspergillus are able to proliferate in a large number of environments on organic substrates. The spores of these opportunistic pathogens, when inhaled, can cause serious and often fatal infections in a wide variety of captive and free-roaming wild birds. The relative importance of innate immunity and the level of exposure in the development of the disease can vary considerably between avian species and epidemiological situations. Given the low efficacy of therapeutic treatments, it is essential that breeders or avian practitioners know the conditions that favor the emergence of Aspergillosis in order to put adequate preventive measures in place.

The Current Host Range of Hepatitis E Viruses

Hepatitis E virus (HEV) is an emerging zoonotic pathogen transmitting both human to human via the fecal oral route and from animals to humans through feces, direct contact, and consumption of contaminated meat products. Understanding the host range of the virus is critical for determining where potential threats to human health may be emerging from and where potential reservoirs for viral persistence in the environment may be hiding. Initially thought to be a human specific disease endemic to developing countries, the identification of swine as a primary host for genotypes 3 and 4 HEV in industrialized countries has begun a long journey of discovering novel strains of HEV and their animal hosts. As we continue identifying new strains of HEV in disparate animal species, it is becoming abundantly clear that HEV has a broad host range and many of these HEV strains can cross between differing animal species. These cross-species transmitting strains pose many unique challenges to human health as they are often unrecognized as sources of viral transmission.

Brain Infection by Hepatitis E Virus Probably via Damage of the Blood-Brain Barrier Due to Alterations of Tight Junction Proteins

Extrahepatic injury, particularly neurologic dysfunctions such as Guillain-Barré syndrome, neurologic amyotrophy, and encephalitis/meningoencephalitis/myositis were associated with HEV infection, which was supported by both clinical and laboratory studies. Thus, it is crucial to figure out how the virus invades into the central nervous system (CNS). In this study, CNS lesions were determined in rabbits and Mongolian gerbils inoculated with genotype 4 HEV. Junctional proteins were detected in HEV infected primary human brain microvascular cells (HBMVCs). Viral encephalitis associated perivascular cuffs of lymphocytes and microglial nodules were observed in HEV infected rabbits. Both positive- and negative-strand of HEV RNA was detected in brain and spinal cord in rabbits intraperitoneally infected with HEV at 28 dpi (days postinoculation), but not in rabbits gavaged with HEV. HEV ORF2 protein was further examined in both brain and spinal cord sections of infected rabbits, with positive signals located mainly in neural cells and perivascular areas. Ultrastructural study showed thickened and reduplicated basement membranes of capillary endothelium in HEV RNA positive brain tissues. In vitro study showed loss of tight junction proteins including Claudin5, Occludin, and ZO-1 (zonula occludens-1) in HBMVCs inoculated with HEV for 48 h. These findings indicated that disruption of the blood-brain barrier (BBB) might be potential mechanisms of HEV invasion into the CNS. It provides new insights to further study HEV associated neurologic disorders and will be helpful for seeking potential therapeutics for HEV infection in the future.

Novel orthohepeviruses in wild rodents from São Paulo State, Brazil

The Hepeviridae comprise single-stranded positive-sense RNA viruses classified into two genera, Orthohepevirus and Piscihepevirus. Orthohepeviruses have a wide host range that includes rodents, but previous studies had been restricted to rodents of the Muridae family. In this study, we applied a high-throughput sequencing approach to examine the presence of orthohepeviruses in rodents from São Paulo State, Brazil. We also used RT-PCR to determine the frequency of orthohepeviruses in our sampled population. We identified novel orthohepeviruses in blood samples derived from Necromys lasiurus (1.19%) and Calomys tener (3.66%). Therefore, our results expand the host range and viral diversity of the Hepeviridae family.

Public health risks associated with hepatitis E virus (HEV) as a food-borne pathogen

Hepatitis E virus (HEV) is an important infection in humans in EU/EEA countries, and over the last 10 years more than 21,000 acute clinical cases with 28 fatalities have been notified with an overall 10-fold increase in reported HEV cases; the majority (80%) of cases were reported from France, Germany and the UK. However, as infection in humans is not notifiable in all Member States, and surveillance differs between countries, the number of reported cases is not comparable and the true number of cases would probably be higher. Food-borne transmission of HEV appears to be a major route in Europe; pigs and wild boars are the main source of HEV. Outbreaks and sporadic cases have been identified in immune-competent persons as well as in recognised risk groups such as those with pre-existing liver damage, immunosuppressive illness or receiving immunosuppressive treatments. The opinion reviews current methods for the detection, identification, characterisation and tracing of HEV in food-producing animals and foods, reviews literature on HEV reservoirs and food-borne pathways, examines information on the epidemiology of HEV and its occurrence and persistence in foods, and investigates possible control measures along the food chain. Presently, the only efficient control option for HEV infection from consumption of meat, liver and products derived from animal reservoirs is sufficient heat treatment. The development of validated quantitative and qualitative detection methods, including infectivity assays and consensus molecular typing protocols, is required for the development of quantitative microbial risk assessments and efficient control measures. More research on the epidemiology and control of HEV in pig herds is required in order to minimise the proportion of pigs that remain viraemic or carry high levels of virus in intestinal contents at the time of slaughter. Consumption of raw pig, wild boar and deer meat products should be avoided.

Detection of Genotype 4 Swine Hepatitis E Virus in Systemic Tissues in Cross-Species Infected Rabbits

Increasing evidence demonstrates that hepatitis E virus (HEV) can be transmitted across species. According to previous reports, swine HEV has two genotypes, genotype 3 and 4, and both can infect humans by the fecal-oral route. Thus, it is crucial for the control of HEV zoonotic transmission to evaluate the dynamics of viral shedding and distribution in different tissues during cross-species infection by HEV. In this study, rabbits were infected with genotype 4 swine HEV by the intraperitoneal route. The results showed that HEV RNA not only shed in the feces but also in the saliva of some rabbits during infection with swine HEV. Viremia appeared late after infection, and anti-HEV IgG was not obvious until the appearance of high viremia levels. After the rabbits were euthanized, a histopathological examination showed that the livers developed overt hepatitis accompanied by an elevation of alanine aminotransferase (ALT) and aspartate transaminase (AST). Furthermore, HEV RNA was detected in various tissues, especially in the salivary glands and tonsils. Subsequently, negative-stranded HEV RNA was practiced in tissues with positive HEV RNA, which demonstrated that HEV replicated in the tissues. Next, we harvested additional tissues from the liver, salivary gland, tonsil, spleen, thymus gland, lymph node and intestine, which are known as replication sites of swine HEV. Additionally, we also observed the HEV antigen distributed in the organs above through immunohistochemical staining. These results demonstrate that rabbits could be used as an animal model for researching cross-species infection of genotype 4 HEV. It is also noteworthy that HEV can shed in the saliva and presents the risk of droplet transmission. These new data provide valuable information for understanding cross-species infection by HEV.

Evidence of genotypes 1 and 3 of avian hepatitis E virus in wild birds

Although the presence of four genotypes of avian hepatitis E virus (HEV) in chickens has been demonstrated, its natural host range is still barely known. In this study, swab samples from 626 wild birds originating from 62 bird species were investigated for HEV detection by molecular methods. The aim was to explore the cross-species infection of avian HEV and to compare the genetic diversity between strains infecting chicken and wild birds. In total, 8 positive samples from 4 different bird species (song thrush, little owl, feral pigeon and common buzzard) were identified and further confirmed by partial sequencing of ORF3. Based on a 237bp fragment of the capsid gene retrieved from 5 samples, phylogenetic analysis revealed the presence of avian HEV genotypes 1 and 3 in wild birds. The wild bird isolates shared 82.7-84.8% and 85.7-100% nucleotide sequence identity, respectively, to chicken isolates from the corresponding genotype. For two of the genotype 1 samples (14-2901 and 14-2906), from feral pigeons, genotype assignment could be also confirmed by phylogenetic analysis based on partial nucleotide sequence of the helicase gene. For the first time, the appearance of genotype 1 in Europe was detected, which together with close genetic relationship between HEVs present in chickens and wild birds indicates cross-species transmission.

A novel avian-like hepatitis E virus in wild aquatic bird, little egret (Egretta garzetta), in Hungary

Hepatitis E virus (HEV), family Hepeviridae, has public health concerns because of its zoonotic potential; however, the host species spectrum, animal to animal transmissions, the natural chain of hepevirus infections and the genetic diversity of HEV in wildlife especially in birds are less known. Using random amplification and next generation sequencing technology a genetically divergent avian HEV was serendipitously identified in wild bird in Hungary. HEV RNA was detected with high faecal viral load (1.33×10⁸genomiccopies/ml) measured by real-time PCR in faecal sample from a little egret (Egretta garzetta). The complete genome of HEV strain little egret/kocsag02/2014/HUN (KX589065) is 6660-nt long including a 18-nt 5' end and a 103-nt 3' end (excluding the poly(A)-tail). Sequence analyses indicated that the ORF1 (4554nt/1517aa), ORF2 (1728nt/593aa) and ORF3 (339nt/112aa) encoded proteins of little egret/kocsag02/2014/HUN shared the highest identity (62.8%, 71% and 61.5%) to the corresponding proteins of genotype 1 avian (chicken) HEV in species Orthohepevirus B, respectively. This study reports the identification and complete genome characterization of a novel orthohepevirus distantly related to avian (chicken) HEVs at the first time in wild bird. It is important to recognize all potential hosts, reservoirs and spreaders in nature and to reconstruct the phylogenetic history of hepeviruses. Birds could be an important reservoir of HEV generally and could be infected with genetically highly divergent strains of HEV.

Divergent hepatitis E virus in birds of prey, common kestrel (Falco tinnunculus) and red-footed falcon (F. vespertinus), Hungary

Hepatitis E virus (HEV), family Hepeviridae, has raised considerable public health concerns because of its zoonotic potential; however, the animal to animal transmissions and the natural chain of hepevirus infections in wildlife are less known. Using random amplification and next generation sequencing technology a novel HEV in birds of prey was serendipitously identified in Hungary. HEV RNA was detected in total of 2 (18%) of the 11 and 1 (14%) of the 7 faecal samples from common kestrels and red-footed falcons, respectively. High faecal viral load (2.03×10(8) genomic copies/ml) measured by qPCR. The complete genome of strain kestrel/MR22/2014/HUN (KU670940) HEV is 7033-nt long including a 35-nt 5'end and a 63-nt 3'end (excluding the poly(A)-tail). Sequence analyses indicated that the ORF1 (4920nt/639 aa), ORF2 (1989nt/662 aa) and ORF3 (360nt/119aa) proteins of kestrel/MR22/2014/HUN shared the highest identity (58.1%, 66.8% and 28.5%) to the corresponding proteins of ferret, rat and human genotype 4 Orthohepeviruses, respectively. Interestingly, the ORF3 protein is potentially initiated with leucine (L) using an alternate, non-AUG (UUG) start codon. This study reports the identification and complete genome characterization of a novel Orthohepevirus species related to mammalian HEVs in birds of prey. It is important to recognize all potential hosts, reservoirs and spreaders in nature and to reconstruct the phylogenetic history of hepeviruses.