Nipah virus infection | |
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Structure of a Henipavirus | |
Specialty | Infectious diseases ![]() |
Symptoms | None, fever, cough, headache, diarrhea, confusion [1] |
Complications | Inflammation of the brain, seizures [2] |
Usual onset | 5 to 14 days after exposure [1] |
Causes | Nipah virus (spread by direct contact) [1] |
Diagnostic method | Based on symptoms, confirmed by laboratory testing [1] |
Prevention | Avoiding exposure to bats and to sick pigs and people. |
Treatment | Supportive care only [2] |
Prognosis | The case fatality rate of Nipah virus infection is estimated at 40–75% but can vary by outbreak depending on surveillance and clinical management in affected areas. [3] |
Frequency | ~701 human cases (1998 to May 2018) [4] [5] |
Deaths | ~50 to 75% risk of death [4] [6] |
A Nipah virus infection is a viral infection caused by the Nipah virus. Symptoms from infection vary from none to fever, cough, headache, shortness of breath, and confusion. This may worsen into a coma over a day or two, and 50 to 75% of those infected die. Complications can include inflammation of the brain and seizures following recovery. [2] [1]
The Nipah virus (NiV) is a type of RNA virus in the genus Henipavirus, which normally circulates among fruit bats of the genus Pteropus. [7] Spread typically requires direct contact with an infected source; it can both spread between people and from other animals to people. Diagnosis is based on symptoms and confirmed by laboratory testing. [2] [1]
Management is restricted to supportive care; as of 2021 [update] there is neither vaccine nor specific treatment. [2] Preventive measures include avoiding exposure to bats and infected animals such as pigs, and not drinking raw date palm sap. [1] As of May 2018 about 700 human cases of Nipah virus were estimated to have occurred, and 50 to 75 percent of those infected died. [4] [6] [5]
The disease was first identified in 1998 by a team of researchers at the Faculty of Medicine, University of Malaya during an outbreak in Malaysia. [8] The majority of the patients in Malaysia diagnosed with the disease were referred to and treated at the University of Malaya Medical Centre. The virus was isolated and identified in 1999. [2] The disease is named after a village in Malaysia, Sungai Nipah. Pigs may also be infected, and millions were killed by Malaysian authorities in 1999 to stop the spread of disease, a measure which proved to be successful. [2] [9]
Human infections range from asymptomatic infection to acute respiratory infection, seizures and fatal encephalitis. This illness typically initially presents as 3-14 days of fever and headache, often accompanied by a cough, sore throat, difficulty breathing, and other signs of respiratory illness. [1] Infected people initially develop symptoms that include fever, headaches, myalgia, vomiting and sore throat. This can be followed by dizziness, drowsiness, altered consciousness, and neurological signs that indicate acute encephalitis. Some people can also experience atypical pneumonia and severe respiratory problems, including acute respiratory distress. Encephalitis and seizures occur in severe cases, progressing to coma within 24 to 48 hours. [1]
The incubation period is from 4 to 14 days but an incubation period as long as 45 days has been reported. [1]
Death occurs in 40-75% of cases, and some long-term side effects of infection include persistent convulsions and personality changes. Most survivors make a full recovery, although some are left with residual neurological conditions after acute encephalitis. Some cases of relapse have been reported. [1]
The initial case in human outbreaks of Nipah virus has always been zoonotic [8] from exposure to contaminated secretions or tissues of infected bats or pigs. Subsequent human-to-human transmission of Nipah virus occurs via close contact with NiV-infected persons or exposure to NiV-infected body fluids (e.g., blood, urine, nasal secretions). [1]
Most experts do not classify Nipah virus as airborne, though there is consensus that transmission can—and does—occur from short-range exposure to NiV-infected respiratory droplets in close contact settings. [10]
Indirect transmission of Nipah virus via contaminated fomites is likely responsible for many cases in which there was no known direct contact with a NiV-infected person or animal. [1]
The risk of exposure is high for hospital workers and caretakers of those infected with the virus. In Malaysia and Singapore, Nipah virus infected people with close contact to infected pigs. In Bangladesh and India, the disease has been linked to consumption of raw date palm sap (toddy), eating of fruits partially consumed by bats, and using water from wells inhabited by bats. [11] [12]
During acute and convalescent stages of the disease, RNA can be detected using reverse transcriptase polymerase chain reaction (RT-PCR) from throat swabs, cerebrospinal fluid, urine and blood analysis. [1]
After recovery, IgG and IgM antibody detection can confirm a prior Nipah virus infection. Immunohistochemistry on tissues collected during autopsy also confirms the disease. [1]
Prevention through sanitary practices is the best protection. The likelihood of infection through animal transmission can be reduced by avoiding exposure to sick pigs, and to bats where the disease is endemic. Bats harbor a significantly higher proportion of zoonotic viruses than all other mammalian orders, [14] and are known not to be affected by the many viruses they carry, apparently due to their developing special immune systems to deal with the stress of flying. [15] Infection via bats can be caused by drinking raw palm sap (palm toddy) contaminated by bat excreta, [16] eating fruits partially consumed by bats, and using water from wells infested by bats. [12] Bats are known to drink toddy that is collected in open containers, and occasionally urinate in it, which contaminates it with the virus. [16]
Standard infection control practices can protect against human-to-human hospital-acquired infections. [1]
In January 2024 a candidate vaccine, ChAdOx1 NipahB, commenced Phase I clinical trials after completing laboratory and animal testing. [17] [18]
As of 2020 [update] , there is no specific treatment for Nipah virus infection. [19] The mainstay of treatment is supportive care. While tentative evidence supports the use of ribavirin, it has not yet been studied in people with the disease. [1] Specific antibodies have also been studied in an animal model with potential benefit. [1] Acyclovir, favipiravir, [19] and remdesivir [20] have been assessed as potential antivirals against Nipah virus.
M 102.4 is a nonpatented monoclonal antibody developed by Christopher C. Broder, a professor of immunology and microbiology at Uniformed Services University of the Health Sciences in Maryland. It proved highly effective in animal models. 50 doses were sent to Kerala in 2018, but it is not clear if they were used in humans.[ citation needed ]
Nipah virus infection is fatal in 40 to 70 percent of cases, [1] though some outbreaks have had 100% case fatality rate. [21]
Those who survive the initial infection often struggle with debilitating long-term neurological sequelae, including memory loss, impaired cognition, seizures, convulsions, and personality changes. [1]
Moreover, Nipah virus is known to be able to persist and lie dormant in survivors and to re-activate many months or years after the initial infection. [1] Deaths from re-activation of latent Nipah virus have been reported. [22]
Nipah virus outbreaks have been reported in Malaysia, Singapore, Bangladesh and India. The area is known as the Nipah Belt. The highest mortality due to Nipah virus infection was found in Bangladesh,[ citation needed ] where outbreaks are typically seen in winter. [23] Nipah virus was first seen in 1998 in peninsular Malaysia in pigs and pig farmers. By mid-1999, more than 265 human cases of encephalitis, including 105 deaths, had been reported in Malaysia, and 11 cases of either encephalitis or respiratory illness with one fatality were reported in Singapore. [24] In 2001, Nipah virus was reported from Meherpur District, Bangladesh [25] [26] and Siliguri, India. [25] The outbreak again appeared in 2003, 2004 and 2005 in Naogaon District, Manikganj District, Rajbari District, Faridpur District and Tangail District. [26] In Bangladesh there were further outbreaks in subsequent years. [27] [6]
Ribavirin, m102.4 monoclonal antibody, and favipiravir were being studied as treatments as of 2019. [53]
Ribavirin has been studied in a small number of people. As of 2011 [update] , it was unclear whether it was useful, although a few people had returned to normal life after treatment. [54] In vitro studies and animal studies have shown conflicting results in the efficacy of ribavirin against NiV and Hendra, with some studies showing effective inhibition of viral replication in cell lines, [55] [56] whereas some studies in animal models showed that ribavirin treatment only delayed but did not prevent death after NiV or Hendra virus infection. [57] [58]
In 2013, the anti-malarial drug chloroquine was shown to block the critical functions needed for maturation of Nipah virus, although no clinical benefit was observed. [4]
Passive immunization using a human monoclonal antibody, m102.4, that targets the ephrin-B2 and ephrin-B3 receptor-binding domain of the henipavirus Nipah G glycoprotein was evaluated in the ferret model as post-exposure prophylaxis. [4] [1] m102.4 has been used in people on a compassionate use basis in Australia, and was in pre-clinical development in 2013. [4]
The fictional MEV-1 virus featured in the 2011 film Contagion was based on a combination of Nipah and measles virus. [59]
A Malayalam movie, Virus , was released in 2019, based on the 2018 outbreak of Nipah virus in Kerala, India. [60] [61]
In series 4 episode 1 of The Good Karma Hospital , a patient is admitted with Nipah.[ citation needed ]
Episode 7 of the Korean drama Doctor John also features a Nipah virus outbreak.[ citation needed ]
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There have been several outbreaks of Nipah virus in Kerala, some of which have been traced to fruit bats. The NIV Pune confirmed the first case of Nipah virus in Kerala in May 2018. A total of 21 Nipah virus infected individuals passed away in between 2018 and 2024.
Virus is a 2019 Indian Malayalam-language medical thriller film co-produced and directed by Aashiq Abu set against the backdrop of the 2018 Nipah virus outbreak in Kerala. The film was written by Muhsin Parari and Suhas-Sharfu. It stars an ensemble cast that includes Kunchacko Boban, Indrajith Sukumaran, Asif Ali, Tovino Thomas, Parvathy Thiruvothu, Rahman, Indrans, Jinu Joseph, Sreenath Bhasi, Dileesh Pothan, Rima Kallingal, Madonna Sebastian, Ramya Nambeeshan, Joju George, Soubin Shahir and Revathi.
The 1998–1999 Malaysia Nipah virus outbreak occurred from September 1998 to May 1999 in the states of Perak, Negeri Sembilan and Selangor in Malaysia. A total of 265 cases of acute encephalitis with 105 deaths caused by the virus were reported in the three states throughout the outbreak. At first, the Malaysian health authorities thought that Japanese encephalitis (JE) was the cause of the infection. This misunderstanding hampered the deployment of effective measures to prevent the spread, before the disease was identified by a local virologist from the Faculty of Medicine, University of Malaya as a newly discovered agent. It was named Nipah virus (NiV). The disease was as deadly as the Ebola virus disease (EVD), but attacked the brain system instead of the blood vessels. University of Malaya's Faculty of Medicine and the University of Malaya Medical Centre played a major role in serving as a major referral centre for the outbreak, treating majority of the Nipah patients and was instrumental in isolating the novel virus and researched on its features.
Ghanaian bat henipavirus (also known Kumasi virus belongs to the genus Henipavirus in the family Paramyxoviridae. Human infections are caused by zoonotic events where the virus crosses over from another animal species. Therefore, humans are not the innate host for this virus family but instead become infected by peripheral viral reservoirs such as bats and other carriers of the virus. When these virus are spread to humans through zoonotic events they have been found to be one of the most deadly viruses with the capability to infect humans, with mortality rates between 50 and 100%. Therefore, these viruses have been classified as a biosafety level four virus with regards to its pathogenesis when it infects humans.
112 cases since Oct 2013