Seasonality of Date Palm Sap Feeding Behavior by Bats in Bangladesh

Pteropus bats are the natural reservoir for Nipah virus, and in Bangladesh, it is transmitted to people through consumption of raw or fermented date palm sap. Our objective was to understand seasonal patterns of bat feeding on date palm sap at a location where sap is collected year-round. Seven nights each month over three years, we mounted infrared cameras in four trees to observe bats' feeding behavior at date palm trees harvested for fermented sap production. We described the frequency of bat visits, duration of bat visits, and duration of bat-sap contact by month and by year. We captured 42,873 bat visits during 256 camera-nights of observation, of which 3% were Pteropus and 94% were non-Pteropus bats. Though the frequency of Pteropus bat visits to each tree/night was much lower than non-Pteropus bat visits, Pteropus bats stayed in contact with sap longer than non-Pteropus bats. Frequency of bat visits was higher during winter compared to other seasons, which may arise as a consequence of limited availability of food sources during this period or may be related to seasonal characteristics of the sap. Seasonal alignment of sap consumption by humans and bats may have consequences for viral spillover into humans.

High Pathogenicity of Nipah Virus from Pteropus lylei Fruit Bats, Cambodia

We conducted an in-depth characterization of the Nipah virus (NiV) isolate previously obtained from a Pteropus lylei bat in Cambodia in 2003 (CSUR381). We performed full-genome sequencing and phylogenetic analyses and confirmed CSUR381 is part of the NiV-Malaysia genotype. In vitro studies revealed similar cell permissiveness and replication of CSUR381 (compared with 2 other NiV isolates) in both bat and human cell lines. Sequence alignments indicated conservation of the ephrin-B2 and ephrin-B3 receptor binding sites, the glycosylation site on the G attachment protein, as well as the editing site in phosphoprotein, suggesting production of nonstructural proteins V and W, known to counteract the host innate immunity. In the hamster animal model, CSUR381 induced lethal infections. Altogether, these data suggest that the Cambodia bat-derived NiV isolate has high pathogenic potential and, thus, provide insight for further studies and better risk assessment for future NiV outbreaks in Southeast Asia.

Dissecting an Outbreak: A Clinico-epidemiological Study of Nipah Virus Infection in Kerala, India, 2018

Background:

An outbreak of Nipah virus infection was confirmed in Kerala, India in May 2018. Five out of 23 cases including the first laboratory-confirmed case were treated at Baby Memorial Hospital (BMH), Kozhikode. The study describes the clinical characteristics and epidemiology of the Nipah virus outbreak at Kozhikode during May 2018.

Objective:

To study the clinical and epidemiological profile of Nipah virus epidemic that occurred in Kerala in May 2018.

Methods:

A collaborative team of physicians and epidemiologists from BMH, Medical College Hospital (MCH) Kozhikode and from the Indian Medical Association (IMA) conducted this study. The clinical and exposure history and the data on outbreak response were gathered from hospital medical records and through interviewing patient relatives and health workers using questionnaires.

Results:

It was identified that out of the 23 patients with Nipah virus infection, 21 (91.3%) expired. Out of the 21 patients, 18 tested positive for Nipah virus by Real Time polymerase chain reaction (RT-PCR). It has been found that only the index case was infected in the community from fruit bats. Rest of the cases were due to transmission of the virus at three public hospitals. Median age was 45 years. 65% of them were males. Median incubation period was 9.5 days. Fever (100%), altered sensorium (84.2%), tachycardia (63.1%), hypertension (36.8%), segmental myoclonus (15.7%), segmental sweating (15.7%) and shortness of breath (73.6%) were common features. Mean duration of illness was 6.4 days.

Conclusion:

The rapid spread of infection uncovered the miserable state of health care system in implementing infection control measures. The case fatality and the socio-economic burden warrant developing appropriate treatments, vaccines and diagnostics.

Hendra virus vaccine, a one health approach to protecting horse, human, and environmental health

In recent years, the emergence of several highly pathogenic zoonotic diseases in humans has led to a renewed emphasis on the interconnectedness of human, animal, and environmental health, otherwise known as One Health. For example, Hendra virus (HeV), a zoonotic paramyxovirus, was discovered in 1994, and since then, infections have occurred in 7 humans, each of whom had a strong epidemiologic link to similarly affected horses. As a consequence of these outbreaks, eradication of bat populations was discussed, despite their crucial environmental roles in pollination and reduction of the insect population. We describe the development and evaluation of a vaccine for horses with the potential for breaking the chain of HeV transmission from bats to horses to humans, thereby protecting horse, human, and environmental health. The HeV vaccine for horses is a key example of a One Health approach to the control of human disease.