Transmission of Nipah Virus — 14 Years of Investigations in Bangladesh

Abstract

BACKGROUND Nipah virus is a highly virulent zoonotic pathogen that can be transmitted between humans. Understanding the dynamics of person-to-person transmission is key to designing effective interventions. METHODS We used data from all Nipah virus cases identified during outbreak investigations in Bangladesh from April 2001 through April 2014 to investigate case-patient characteristics associated with onward transmission and factors associated with the risk of infection among patient contacts. RESULTS Of 248 Nipah virus cases identified, 82 were caused by person-to-person transmission, corresponding to a reproduction number (i.e., the average number of secondary cases per case patient) of 0.33 (95% confidence interval [CI], 0.19 to 0.59). The predicted reproduction number increased with the case patient’s age and was highest among patients 45 years of age or older who had difficulty breathing (1.1; 95% CI, 0.4 to 3.2). Case patients who did not have difficulty breathing infected 0.05 times as many contacts (95% CI, 0.01 to 0.3) as other case patients did. Serologic testing of 1863 asymptomatic contacts revealed no infections. Spouses of case patients were more often infected (8 of 56 [14%]) than other close family members (7 of 547 [1.3%]) or other contacts (18 of 1996 [0.9%]). The risk of infection increased with increased duration of exposure of the contacts (adjusted odds ratio for exposure of >48 hours vs. ≤1 hour, 13; 95% CI, 2.6 to 62) and with exposure to body fluids (adjusted odds ratio, 4.3; 95% CI, 1.6 to 11). CONCLUSIONS Increasing age and respiratory symptoms were indicators of infectivity of Nipah virus. Interventions to control person-to-person transmission should aim to reduce exposure to body fluids. (Funded by the National Institutes of Health and others.)

Meeting report: 32nd International Conference on Antiviral Research

“…Fortunately, as with the MERS-CoV, there is relatively inefficient NiV person-to-person transmission; however, 90% of those infected progress to acute encephalitis with respiratory complications, and 30% of those who survive experience neurological sequelae. A contact survey that was conducted showed that asymptomatic infections have likely been rare in Bangladesh (Nikolay et al, 2019).…”

“…Models combining healthcare utilization surveys and active NiV case finding efforts at three Bangladesh hospitals suggest that only half of the actual cases are being detected (Hegde et al, 2019). In terms of transmission, males experiencing breathing difficulty were found to be the most efficient at person-to-person transmission (Nikolay et al, 2019). As reviewed by Emily Gurley, caregivers are at greatest risk of infection.…”

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

“…Drinking date palm sap contaminated with urine or saliva of NiV‐infected bats has been identified as a major route of zoonotic transmission of NiV (Chakraborty et al, ; Luby & Gurley, ). However, human‐to‐human NiV transmissions represent 33% of known Nipah virus human cases from Bangladesh between 2001 and 2014 (Nikolay et al, ). This observation, coupled with high mortality rates and the lack of effective therapies or vaccines (Vigant & Lee, ), marks NiV as a significant public health threat in the region with potential for pandemic spread (Luby, ).…”

Reprogrammed Pteropus Bat Stem Cells Present Distinct Immune Signature and are Highly Permissive for Henipaviruses

“…2f). Indeed, the facultative 17 heterochromatin marker H3K27me3 in bat RSCs was distributed within several large foci, rather than 18 being concentrated mainly at the inactivated X chromosome as in PCs. Previously, such numerous 19 prominent H3K27me3 foci were observed in both naïve mouse PSCs33 and in pluripotent and 20 reprogrammed avian cells 31,34 .…”

“…Isolation of new viral strains is an important step and is (generally) 15 attempted in established immortalized cell lines such as IFN-I-deficient simian Vero cells. 16 Propagation of viruses in cell lines other than those of the natural host may lead to selection of virus 17 sub-populations that replicate more efficiently in the chosen cell type, leading to accumulation of 18 adaptive mutations that may prevent adequate assessment of host-pathogen interactions 23 . Therefore, 19 further advancement in the field requires establishment of new bat cell models; indeed, development 20 of novel Pteropus cell lines is particularly important for the field of Henipavirus infection research.…”