As flying foxes are found in different areas including in Kathmandu, Nepal is at high risk of Nipah virus outbreaks
In May 2018, an outbreak of Nipah infection killed 17 people, including a healthcare worker, in Kerala, India. The southern Indian state has put on ‘all-time alert’ after the incident. After the outbreak, Qatar and United Arab Emirates (UAE) have banned imports of all fresh and frozen vegetables and fruits from Kerala.
Nipah virus (NiV) is a zoonotic virus (transmitted to humans from animals) of the genus Henipavirus which belong to the family of Paramyxoviridae that is normally hosted by fruit bats. The first reported outbreak was in Kampang Sungai Nipah (Nipah River Village), Malaysia in late September, 1998. Pigs were the intermediate hosts.
Outbreaks continue to occur in the several parts of India and Bangladesh. According to the US based Centers for Disease Control and Prevention (CDC), multiple outbreaks of Nipah virus now occur in Bangladesh almost every year. This virus has a 70 percent mortality rate. World Health Organization (WHO) has listed Nipah in the list of top ten emerging diseases likely to cause major epidemics in 2015. But there has been no more research for its prevention and control.
Signs and symptoms
Bats that spread Nipah virus are found in abundance in Nepal
Fruit bats are the main reservoir hosts of Nipah virus. Interestingly, this virus does not appear to cause any clinical disease in fruit bats whether they are infected experimentally or naturally. Moreover, studies have proved that the virus can naturally infect horses, pigs, cats, dogs, and humans. Transmission of Nipah virus to humans may occur after direct contact with infected bats, infected pigs, or from other NiV infected people. With its high virulence, this virus can spread from animal-to-human, and human-to-human, often between caregivers and family members of people who are infected.
The incubation period lasts two to 30 days but with more than 90 percent it is two weeks or less. Prodromal signs and symptoms are often nonspecific: fever, headache, myalgia and dizziness. Within a week, neurological symptoms like encephalitis/inflammation of the brain may also appear. At that stage NiV can easily be detected from urine and respiratory secretions, but not from blood. Drowsiness, confusion, and reduced level of consciousness are observed within a few days of infection. Other neurological signs are hyporeflexia or areflexia, segmental myoclonus, gaze palsy and limb weakness. A significant proportion of patients develop psychiatric problems like depression and personality changes among others.
The initial signs and symptoms of Nipah infection are non-specific which delays in diagnosis and creates challenges in early outbreak detection in the affected area. Infection of NiV can be diagnosed in the laboratory with clinical symptoms during the acute phase of infection by using the combination of tests. Body fluids like cerebrospinal fluid (CSF), urine, blood, throat and nasal swabs can be used for viral particles detection through real time polymerase chain reaction (RT-PCR) technique. Neuro-Radiology like MRI of brain is used to observe the virus-associated infection in brain.
Remedial treatment
Treatment of Nipah is limited to supportive care. Intensive supportive care is recommended to severe neurologic and respiratory cases. CDC recommends that, ‘people who are infected should be treated with supportive treatment which includes making patients hydrated, and treating any nausea or vomiting during the course of infection’. There are no effective vaccines available against Nipah virus.
Nonetheless, a vaccine named Equivac HeV has been developed to protect horses and this approach may also be effective in humans. Coalition for Epidemic Preparedness Innovations (CEPI) on May 24 has announced $25 million collaboration with two pharmaceutical companies to develop an effective vaccine.
Centers for Disease Control and Prevention (CDC) says BSL-4 facilities are needed to handle Nipah. BSL-4 laboratories have special engineering and design features to prevent microorganisms from being disseminated into the surrounding environment. Nepal does not have such laboratory yet.
According to Dr Kedar Prasad Ceintury, Director of Epidemiology and Disease Control Division (EDCD) of Ministry of Health, we don’t have proper treatment facilities like isolation ward. There is no possibility of treatment of Nipah related cases even in Bir and TU Teaching hospitals.
According to him, a meeting was held recently between the senior officials of Ministry of Health and representatives of World Health Organization (WHO) which concluded with the decision to send clinical specimens of Nipah infected patients abroad in assistance of WHO for diagnosis if cases appear.
Nipah virus can be prevented by avoiding human exposure to sick bats and pigs and not drinking raw date palm sap. As flying foxes are found in different areas of the country including Kathmandu, Nepal is at high risk of Nipah virus outbreaks. This monsoon fruits may be contaminated with the bat excretions containing the virus. In some parts of the country fruit bat meat is also used in a form of medicine which also enhances the Nipah virus transmission to human.
Our focus should be on surveillance and awareness which will help to prevent future outbreaks. Precautions should be taken to control infection even in health care settings. Let us do this before we become its victims.
Rayamajhee is a Research Faculty at Department of Infectious Diseases, Kathmandu Research Institute for Biological Sciences, Lalitpur and Aryal a PhD Scholar at Central Department of Microbiology, TU
binod@kribs.org.np
me@sagararyal.com al is at high risk of Nipah virus outbreaks
