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One Health
Published in Rebecca A. Krimins, Learning from Disease in Pets, 2020
Bats are also speculated to be the reservoirs of several other zoonotic diseases, particularly coronaviruses (CoVs) such as Severe Acute Respiratory Syndrome (SARS),87 a coronavirus which emerged in China in 2002 and resulted in over 8,000 human illnesses and 774 deaths worldwide;88 and Middle East Respiratory Syndrome coronavirus (MERS-CoV), which emerged in Saudi Arabia in 2012 and has resulted in nearly 2,500 cases and over 850 deaths. MERS-CoV was likely transmitted by bats to dromedary camels in the distant past and is now moving camel-to-person as well as person-to-person.89 Hendra virus, which causes severe and fatal disease in horses and humans in Australia, also has the bat as its reservoir.90
Nipah encephalitis, a fatal encephalitis with bats as reservoir
Published in Avindra Nath, Joseph R. Berger, Clinical Neurovirology, 2020
Because the outbreak involved pig farm workers, the outbreak was initially thought to be due to Japanese encephalitis. Several features distinguished this outbreak from Japanese encephalitis. There was a clustering of cases in members of the same household, which suggests an infection with a high disease attack rate, as opposed to Japanese encephalitis virus which causes symptomatic encephalitis in one in 300 of those infected. Isolation of a new paramyxovirus from cerebrospinal fluid specimens of several patients indicated that this was the etiologic agent [3,4]. The virus was subsequently named Nipah virus, after Sungai Nipah, the village where patients’ specimens yielded the first viral isolates. Viral genomic sequencing has now established Nipah virus as a new paramyxovirus closely related to Hendra virus [4,7]. Hendra virus caused disease among horses and several patients in Australia starting 1994 [8,9]. There is a high degree of nucleotide homology in viral genomes of Hendra virus and Nipah virus that exceeds 70%, and identical amino acid sequences of more than 80% [4,7]. Because of their homology, a new genus called Henipa (Hendra + Nipah) was created for these two viruses [4].
The ecological context
Published in Loretta A. Cormier, Pauline E. Jolly, The Primate Zoonoses, 2017
Loretta A. Cormier, Pauline E. Jolly
The spread of Ebola shares many characteristics with HIV since it may be transmitted through blood and body fluids, but it may involve a longer infection chain (from bats to apes to humans), similar to the Hendra virus in bats, horses, and humans. Quammen (2012) describes a case study of a Hendra virus outbreak in a horse stable in eastern Australia (Quammen 2012). Fruit bats, which are the reservoir, had been roosting in fig trees in a horse pasture, and a horse likely was exposed to the virus by eating grass contaminated with bat urine, feces, or saliva. The virus then spilled over into other horses at the stables, manifesting in virulent infection, with half a dozen horses dying within 12 hours. The horses became effective amplifying agents, and the virus had a secondary spillover into three men who were caretakers of the horses, one of whom died.
A review of mechanistic models of viral dynamics in bat reservoirs for zoonotic disease
Published in Pathogens and Global Health, 2020
Anecia D. Gentles, Sarah Guth, Carly Rozins, Cara E. Brook
Following lyssaviruses, understanding of henipavirus dynamics in bat reservoirs shows the most promise to date – in part a reflection of the feasibility of noninvasive viral surveillance through under-roost urine collection in these systems [82]. Our analysis identified only five studies focused on bat-henipaviruses, but three of these five studies presented mechanistic models fitted to field-derived data [25,27,71]. All three studies reported that waning antibodies post-seroconversion contributes to observed henipavirus dynamics, consistent with findings for bat filoviruses. Collectively, these studies also suggested a possible role for recrudescent infection or loss of immunity and reinfection in recovering henipavirus persistence. Broadly, data-fitted henipavirus models assumed no elevated mortality in infectious individuals; however, [25,suggested this as a possible mechanism for observed declines in seroprevalence in older bats, as also posited for filoviruses. Generalizable trends for bat henipaviruses remain somewhat muddled largely due to the idiosyncratic nature of the datasets modeled – including one purely cross-sectional study [27], one eighteen-month time series [25], and one time series derived from a captive colony [71]. Notably, no existing study has yet to fit a compartmental transmission model to the Australian bat reservoirs for Hendra virus, despite claims that this system is a model system for understanding bat virus spillover [83].
Post-exposure prophylactic vaccine candidates for the treatment of human Risk Group 4 pathogen infections
Published in Expert Review of Vaccines, 2020
James Logue, Ian Crozier, Peter B Jahrling, Jens H Kuhn
Nipah virus (NiV; Paramyxoviridae: Henipavirus), is responsible for encephalitis outbreaks in Southern and Southeast Asia (in particular, Bangladesh, Malaysia, and India) that have been increasing in regularity and severity. After an incubation period generally ranging from a few days to-14 days, human disease most often presents with fever, headache, and other nonspecific symptoms. Patients may present with respiratory symptoms and signs, but most prominently they will rapidly progress to encephalitis and coma within 5 to 7 days. Disease sequelae have been reported, including relapsing encephalitis developing months or years following recovery [117]. Transmission of NiV to humans has been linked to domestic pigs (Sus scrofa domesticus Erxleben, 1777) that have come into contact with NiV natural reservoir hosts (pteropodid bats) [118]. As potential routes of infection are well documented for NiV, PEP vaccination may have the potential to minimize the spread of NiV among humans, especially if implemented following noticeable disease in domestic pigs. Though no currently licensed vaccine for the prevention of NiV infection is available, multiple candidate vaccines have been developed, including rVSIV-vectored and rabies virus-vectored vaccines, which have variable efficacy in animal studies if administered prior to infection [119,120]. These candidate vaccines should be evaluated for PEP efficacy as soon as possible. Likewise, similar candidate PEP vaccines ought to be developed for NiV’s closest relative, Hendra virus, which, thus far, has caused a handful of lethal encephalitis cases [121].
Toward the identification of ZDHHC enzymes required for palmitoylation of viral protein as potential drug targets
Published in Expert Opinion on Drug Discovery, 2020
Mohamed Rasheed Gadalla, Michael Veit
The F-protein of many paramyxoviruses is S-acylated at one or several cysteines located in the inner part of the TMR, at least in the case of Newcastle Disease virus with stearate [41]. It is controversial whether acylation of F affects its fusion activity; removal of certain (but not each) acylated cysteine residue from the F-protein of measles virus reduced its cell–cell fusion activity, but no such effect was reported for the human respiratory syncytial virus [69,70]. Nipah and Hendravirus contain a cysteine in the middle of the transmembrane region of F, but have not been analyzed for S-acylation of its proteins.