Beware of deadly Nipah virus
Lt Col Nazmul Huda Khan :
In Bangladesh, winter is the traditional date palm sap gathering season and the raw sap is a popular drink in rural areas.
The deadliest Nipah virus (NiV) infection outbreak coincides with this season linked with this sap, appearing between December and May.
Infection is caused by the consumption of the raw sap of a date palm tree which has been contaminated with urine or saliva from infected fruit bats.
When the sap is consumed, the virus infects the human body. It has been prevalent in Bangladesh since 2001.
There has been a total of 335 people infected with it and 237 of those people have passed away as a result of infection.
In the last year, 11 cases including eight deaths have been reported across two divisions, Dhaka and Rajshahi in Bangladesh.
In Bangladesh, outbreaks have taken place in a group of 10 districts so far. Those are Meherpur, Noagoan, Rajbari, Faridpur, Tangail, Thakurgaon, Kushtia, Manikgonj, Rajshahi, and Lalmonirhat known as the “Nipah belt”.
According to the World Health Organization (WHO), NiV infection is a zoonotic disease that typically transmits from animal to human. From 1998 to 1999, NiV infection among humans was first identified in Malaysia.
This outbreak killed 105 people in that country. By this time, the outbreak had spread to Singapore. The virus entered Singapore through the pig slaughterhouse.
In early 2001, an outbreak due to the NiV was recorded in India that killed 45 infected individuals. Since then, there have been more than 12 outbreaks, all in South Asia. Scientists later identified the virus and its reservoir host as fruit bats.
The epidemics in Malaysia and Singapore happened because of pigs, as the pigs may have been the intermediate hosts. The pigs may have consumed bat contaminated fruits.
Once someone is infected by NiV through consumption of the raw sap, there is the possibility of human to human transmission. It may also get transmitted through food contaminated with the virus. Even human transmission of this deadly virus is possible.
This virus has been found in urine and respiratory secretions of infected individuals. The NiV is an RNA virus that may mutate suddenly and increase its power of transmission and fatality. It is a potential virus that may cause a pandemic on a global scale.
The incubation period is believed to range from 4 to 14 days. However, an incubation period up to 45 days has been reported too. NiV infection in humans causes a range of clinical presentations, from asymptomatic to acute respiratory infection and fatal brain involvement. Infected people initially develop symptoms including fever, headache, muscle pain, vomiting and sore throat.
This can be followed by dizziness, drowsiness, altered consciousness and neurological disorders. Some people can also experience pneumonia and severe respiratory problems.
The majority of Nipah patients in the country die within three days of hospitalization. Case Fatality Rate (CFR) is about 75%. People who survive may have long-term neurologic conditions. Approximately 20% of patients are left with residual neurological consequences like encephalitis.
There are currently no specific treatments for this viral infection. The majority of treatments for those infected with the NiV are symptomatic and supportive.
Ribavirin is normally used as a broad spectrum antiviral during the outbreak as used in Malaysia, which lowered mortality. In Singapore, Acyclovir was utilized. In India, anti G and anti F monoclonal antibodies were utilized in emergency situations.
To contain this NiV infection, several public health programs have been implemented in Bangladesh. Outbreak investigation including contact tracing is a continuous process by the National Rapid Response Team (NRRT).
Health sector and the concerned are focusing on strengthening the existing surveillance system; case management and information, education and communication (IEC) content for advocacy and awareness among the people.
The infectious disease hospital (IDH) in Dhaka has been designated to support the quarantine and isolation of suspected Nipah virus infected cases.
To contain this deadly virus, consumption of raw date palm sap should be strictly prohibited.
However boiled sap can be taken so as molasses. Efforts to prevent transmission should focus on decreasing bat access to date palm sap and other fresh food products.
Freshly collected fruits should be thoroughly washed and peeled before consumption. Fruits with signs of bat bites should be discarded.
The risk of international transmission via fruits or fruit products contaminated with urine or saliva from infected fruit bats can be prevented by washing them thoroughly and peeling them before consumption.
Close unprotected physical contact with Nipah virus infected people should be avoided. Hand washing should be regularly practiced after caring for or visiting sick people.
Health care workers caring for patients with suspected or confirmed infection or handling their specimens, should implement standard infection control precautions at all times.
As human-to-human transmission has been reported among caregivers including family members and in health-care settings, contact and droplet precautions should be used in addition to standard precautions.
(The writer a public health specialist deputed to Kuwait. )
