Origin and evolution of Nipah virus

Abstract

Nipah virus, member of the Paramyxoviridae family, is classified as a Biosafety Level-4 agent and category C priority pathogen. Nipah virus disease is endemic in south Asia and outbreaks have been reported in Malaysia, Singapore, India, and Bangladesh. Bats of the genus Pteropus appear to be the natural reservoir of this virus. The aim of this study was to investigate the genetic diversity of Nipah virus, to estimate the date of origin and the spread of the infection. The mean value of Nipah virus N gene evolutionary rate, was 6.5 × 10(-4) substitution/site/year (95% HPD: 2.3 × 10(-4)-1.18 × 10(-3)). The time-scaled phylogenetic analysis showed that the root of the tree originated in 1947 (95% HPD: 1888-1988) as the virus entered in south eastern Asiatic regions. The segregation of sequences in two main clades (I and II) indicating that Nipah virus had two different introductions: one in 1995 (95% HPD: 1985-2002) which correspond to clade I, and the other in 1985 (95% HPD: 1971-1996) which correspond to clade II. The phylogeographic reconstruction indicated that the epidemic followed two different routes spreading to the other locations. The trade of infected pigs may have played a role in the spread of the virus. Bats of the Pteropus genus, that are able to travel to long distances, may have contributed to the spread of the infection. Negatively selected sites, statistically supported, could reflect the stability of the viral N protein.

Nipah shell disorder, modes of infection, and virulence

“…Many of the pigs were initially infected by eating fruits that were partially eaten by fruits bats, which had left their virus-laden saliva behind (4)(5)(6). Upon isolation and sequencing of the virus, it was revealed that the culprit was a novel RNA virus from Paramyxoviridae family, which includes the Hendra (HeV), mumps (MuV), and measles (MeV) viruses [4][5][6][7]. The symptoms for Nipah infections often include an initial flu-like fever that often follows by irritations, coma, and then death.…”

“…In 2001, a different NiV strain was observed in Bangladesh [4]. There were outbreaks in India or Bangladesh each year thereafter.…”

Population genetics of fruit bat reservoir informs the dynamics, distribution and diversity of Nipah virus

“…Thus, our molecular evidence points to a long history of human–bat cohabitation in Bangladesh with a bat population that has increased steadily over time. While it is difficult to reconstruct the deep evolutionary history of NiV from small gene fragments due to homoplasy and the rapid evolution of RNA viruses (Lo Presti et al, ), it is plausible that bat–human viral spillover events have been part of human history in the region for some time and only recently appreciated due to increased surveillance efforts. A spatial analysis of NiV spillover in Bangladesh supports this assumption, with 45% of the variance in the number of spillover events per district explained by the distance to the nearest NiV surveillance hospital (Cortes et al, ).…”

Who acquires infection from whom and how? Disentangling multi-host and multi-mode transmission dynamics in the ‘elimination’ era

“…space state modelling) to reconstruct cross-species transmission events. The latter can be particularly useful to also discriminate between recent cross-species transmissions, many of which may result in dead-end infections, and host shifts that reflect successful onwards transmission in the new host species.[9,81,97–99]4. what are the potential modes of transmission/transmission pathways?studies of the presence of pathogen in different body fluids/excreta can identify or confirm zoonotic sources of infections and indicate unconventional or previously unknown transmission pathways aiding the understanding of transmission pathways and providing focus for epidemiological studies.[100–102]experimental infections can demonstrate potential for alternative pathways that may not have been considered, and may identify which modes of transmission are most important.[49,103,104]5.…”

“…The difficulty here is that surveillance and reporting of animal diseases is often poor, especially in wildlife but also in livestock diseases in many countries. For many diseases with animal reservoirs of infection, occasional spillover into the human population is often the only indication of ongoing and poorly understood epizootic or enzootic transmission, as we have seen with outbreaks of Ebola [131] and Nipah virus [99]. …”