Nipah Virus Disease: Epidemiological, Clinical, Diagnostic and Legislative Aspects of This Unpredictable Emerging Zoonosis

Abstract

Nipah virus (NiV) infection is a viral disease caused by a Henipavirus, belonging to the Paramyxoviridae family, responsible for a zoonosis. The course of the disease can be very serious and lead to death. NiV natural hosts are fruit bats (also known as megabats) belonging to the Pteropodidae family, especially those of the Pteropus genus. Natural infection in domestic animals has been described in farming pigs, horses, domestic and feral dogs and cats. Natural NiV transmission is possible intra-species (pig-to-pig, human-to-human) and inter-species (flying bat-to-human, pig-to-human, horse-to-human). The infection can be spread by humans or animals in different ways. It is peculiar how the viral transmission modes among different hosts also change depending on the geographical area for different reasons, including different breeding methods, eating habits and the recently identified genetic traits/molecular features of main virus proteins related to virulence. Outbreaks have been described in Malaysia, Singapore, Bangladesh, India and the Philippines with, in some cases, severe respiratory and neurological disease and high mortality in both humans and pigs. Diagnosis can be made using different methods including serological, molecular, virological and immunohistochemical methods. The cornerstones for control of the disease are biosecurity (via the correct management of reservoir and intermediate/amplifying hosts) and potential vaccines which are still under development. However, the evaluation of the potential influence of climate and anthropogenic changes on the NiV reservoir bats and their habitat as well as on disease spread and inter-specific infections is of great importance. Bats, as natural reservoirs of the virus, are responsible for the viral spread and, therefore, for the outbreaks of the disease in humans and animals. Due to the worldwide distribution of bats, potential new reports and spillovers are not to be dismissed in the future.

Nipah outbreak in Bangladesh: are we paying enough heed?

“…The government of Bangladesh (and other countries at acute risk) should work together with WHO for the introduction of wellequipped laboratories to aid research, provision of diagnostic facilities (often inaccessible and expensive), the appointment of health care professionals proficient in NiV disease management as well as the launch of training programs. NiV infection being a zoonotic infection has to be dealt with through "one health program," incorporating risk factors related to humans, animals, and the environment into a single integrated plan [1,7] .…”

Indiscriminate activities of different Henipavirus polymerase complex proteins allow for efficient minigenome replication in hybrid systems

“…HeV was identified in Australia in 1994 and is associated with severe respiratory and neurological disease in horses (10). The case fatality rates of NiV and HeV in humans is 60-100% and there are no efficacious antiviral therapeutics and licensed vaccines for human use (11, 12). To date, a vaccine to protect horses from HeV has been commercialized in Australia.…”

Robust evidence for bats as reservoir hosts is lacking in most African virus studies: a review and call to optimize sampling and conserve bats

“…Many outbreaks of emerging diseases occur in Africa, which has a unique, diverse and ecologically important assemblage of bat species [9,10]. Unlike the well-characterized and well-known Australian and SE Asian Henipavirus-Pteropus flying fox systems [11,12], and with the exception of comprehensive work on the African Orthomarburgvirus-Rousettus aegyptiacus system [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28], the disease ecology of African bats is understudied, especially in light of African bat biodiversity and the size of the continent. Herein, we review published field studies on African bat viruses, summarizing and analysing the work published through 2020 to evaluate the types and quality of data available, trends in species and localities sampled, knowledge gaps and conservation concerns, and to make recommendations for best practices that will improve virological study metadata.…”