Interventions for prevention of Nipah virus transmission and infection in Bangladesh

Nipah virus (NiV) infections have been prevalent in Bangladesh since 2001. This virus is usually transmitted from infected bats to humans, and from humans to humans in Bangladesh. The most common source of transmission of Nipah virus in Bangladesh is through the consumption of a drink made from raw date palm sap that has been contaminated by infected bats’ saliva or urine. This paper describes several interventions to prevent the transmission of Nipah virus, namely, behavior change interventions, surveillance of cases, and quarantine of infected individuals. This paper also briefl y touches upon the recent advancements in the development of vaccines against Nipah virus. Behavior change interventions, namely educating individuals at risk, either in person or through mass media, is an effective way of spreading awareness about and preventing the transmission of NiV. Surveillance systems can help early case detection; however, this might yield misleading numbers if there is underreporting of cases. Quarantine of infected persons is likely to be expensive and would require the presence of extensively trained personnel. Vaccines against NiV are currently being developed and the results from animal tests have been promising. In Bangladesh, given the lack of resources, behavior change intervention would be the most cost-effective way of preventing the spread of NiV, compared to routine surveillance and/or quarantine of cases. Therefore, in order to prevent NiV infections, focus should be geared towards behavior change communication through education about the transmission of NiV, provided to those living in high-risk areas of Bangladesh. Mini-Review Interventions for prevention of Nipah virus transmission and infection in Bangladesh

virus encephalitis [2,4]. Nipah virus infections are becoming increasingly virulent in Bangladesh, with a case-fatality rate of >70% [2]. NiV infection is, therefore, an important public health problem in Bangladesh.
Transmission of NiV is preventable. The major interventions that have been implemented for prevention of NiV transmission in Bangladesh are behavior change interventions, setting up surveillance systems, efforts to produce vaccines and quarantine of infected persons. However, several studies conclude that there are limitations pertaining to each of these interventions, that need to be explored and minimized for effective control of transmission of NiV [5][6][7][8]. This paper aims to describe the intervention strategies undertaken in Bangladesh namely, behavior change interventions, surveillance systems and

Introduction
Nipah virus (NiV) is a paramyxovirus, that was fi rst discovered during an outbreak involving pigs and people in Malaysia and Singapore in [1998][1999] People with NiV infections present with cough, respiratory distress and more than 70% of patients suffer from permanent neurological defi cits [1,3]. Some patients also develop Nipah with the following key terms -"Prevention", "Nipah", "Bangladesh". The search results showed 42 articles, out of which 34 were selected based on the timeframe chosen for this paper. Out of 34 articles 13 were relevant and were included in this paper. A timeframe of 10 years was selected.

Results
Several studies have explored the strength of behavior change communication as a strategy to raise awareness among people and thus prevent the transmission of NiV. Researchers have attempted to convey the message about transmission in lay language, with informative photos to aid their description of the biomedical model of transmission of NiV from bats to humans [6]. Attempts have been made to communicate with people directly as well as, via television media to spread knowledge about transmission of NiV [9]. Some studies have compared the results of giving out two different messages of "no raw sap" and "only safe sap" in two different localities [5,9]. The post-intervention results were found to be similar in most studies, with more people reporting that they learned about an infection that is transmitted through the consumption of a drink made from date palm sap contaminated with bats' saliva or urine [5].
The government recommended key prevention methods in Bangladesh were to either refrain from consuming raw date palm sap during the months of outbreak unless the date palm saps were covered with bamboo-skirts, or to boil the drink for 10 minutes before consumption [7].
The different forms of surveillance deployed by researchers include cluster surveillance which aimed to capture the cases of encephalitis due to NiV infection, and case-based surveillance which looked at all NiV cases presenting in hospitals [10]. Some other options for surveillance include the identifi cation of hotspots with a risk of NiV infection, by mapping the distribution of fruit bat habitats and date palm harvesting locations. Surveillance would allow early case detection and thereby reduce case fatalities [7]. In Malaysia, surveillance involved identifying high risk populations-people who handled pigs, pork sellers, pig cullers, based on the knowledge that transmission of NiV occurred from infected pigs to humans in that country [11]. In Bangladesh, however, NiV is primarily transmitted from bats to humans.
No licensed vaccines against NiV currently exist [3]. A single administration of recombinant vesicular stomatitis virus-based vaccine could be protective; however, this is still under study [12]. Surveillance can be a good way to identify cases and can allow us to prevent the onset of new cases. However, we might miss cases, if, for example, a patient got admitted to a government hospital, which was not selected as a surveillance hospital [10]. Similarly, patients suffering from NiV infection or NiV encephalitis may not get admitted to a hospital in the fi rst place, which is a common scenario in Bangladesh, owing to low healthcare utilization [10]. Therefore, the chance of missing cases is quite high and the penalty for missing a case in an endemic zone could be huge, as this will lead to an increase in person-to-person transmission of NiV, increase in the number of cases as well as case fatality. Setting up and monitoring surveillance systems may also be time-consuming.
In low resource settings like Bangladesh, where access to modern lab technologies is scarce, it may not be feasible enough to rely on surveillance alone to prevent the transmission of NiV. Studi es have mentioned that integrating public education with surveillance programs would be more effective, especially in high-risk areas [7]. like ferrets, hamsters, cats etc., which resulted in effective immune responses in them [3]. Another vaccine under development is a recombinant vesicular stomatitis virusbased vaccine which is being tested in animals [12]. However, the affordability of such vaccines by low-and middle-income countries like Bangladesh, remains an issue [3]. Since these vaccines are still under animal testing, it would require more time for vaccines to be fully prepared for administration. Before