According to the Bangladesh Institute of Epidemiology, Disease Control and Research (IEDCR), as of February 2015, nine cases of Nipah virus have been recorded across the country [1]. The reported cases stem from six districts – Nilphamari, Faridpur, Magura, Ponchoghor, Naugaon, and Rajbari [1]. Case analysis reveals that 56% of recent cases have been male, with the median age across those infected, as 15 years of age [1].
A History of Nipah Virus
Nipah virus (NiV) was isolated and identified for the first time in 1998, when pig farmers and individuals who had close contact with pigs, became ill with encephalitis and respiratory illness in Malaysia and Singapore [2,3]. The first outbreak took place in Kampung Sungai Nipah, Malaysia – a location for which the virus would be named after [3]. The first outbreak produced only mild disease in pigs, but resulted in approximately 300 human cases, with 100 fatalities [2]. Case fatality for Nipah in general is estimated to be between 40% to 75%. However, the World Health Organization (WHO) highlights that this rate may vary depending on surveillance capacities involved in the outbreaks [1]. Since the first outbreak, there have been no intermediate hosts associated with subsequent outbreaks – that is, no pigs were linked to human infections. A CDC study discovered that human infections have been due to the consumption of virus-contaminated date palm sap [3,4].
NiV is part of the family Paramyxoviridae, within the genus Henipavirus [2]. Scientists have since traced NiV back to Indian flying foxes, a type of fruit bat found across southern Asia [4]. Date palm sap happens to be a delicacy sought after by both bats and humans [4]. The sap is collected from date palm tree trunks. The trees are tapped using machetes and the flowing sap collected into clay pots overnight [4]. At night, when the bats forage for food, they sometimes drink the sweet sap collected in the pots, and subsequently contaminate the sap with NiV through their bodily fluids, such as saliva, feces, or urine [4]. The unknowingly-contaminated sap is then sold at markets, where direct consumption of NiV results in the spread of the virus through local populations [4].
Preventive Measures
There is no treatment or vaccine for NiV, so preventive measures are of critical importance for protection against infection [1]. Cooking or fermenting palm sap can destroy the virus, but most sap sold at markets is often sold and consumed raw [4]. Therefore, avoiding palm sap completely can prevent NiV infection. Additionally, people can avoid exposure with ill pigs and bats in areas considered to be endemic with NiV [5]. Efforts that include enhanced surveillance systems, increased public awareness, and interventions including the use of bamboo screens on top of the palm sap pots, can also prevent future outbreaks [5,6].
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Sources
[1] http://outbreaknewstoday.com/bangladesh-reports-nine-nipah-virus-cases-to-date-in-2015/
[2] http://www.cdc.gov/vhf/nipah/
[3] http://www.who.int/csr/disease/nipah/en/
