Nipah Virus
Nipah virus, scientific name Nipah Henipavirus, is a bat-borne virus that causes Nipah Virus infection in humans and other animals, a disease with a high mortality rate. Numerous disease outbreaks caused by the Nipah virus have occurred in south and southeast Asia. Nipah Virus belongs to the genus Henipavirus along with the Hendra virus, which has also caused disease outbreaks.
Although the Nipah virus has caused only a few known outbreaks in Asia, it infects a wide range of animals and causes severe disease and death in people, making it a public health concern.
Transmission:
During the first recognized outbreak in Malaysia, which also affected Singapore, most human infections resulted from direct contact with sick pigs or their contaminated tissues. Transmission is thought to have occurred via unprotected exposure to secretions from the pigs, or unprotected contact with the tissue of a sick animal.
In subsequent outbreaks in Bangladesh and India, consumption of fruits or fruit products contaminated with urine or saliva from infected fruit bats was the most likely source of infection.
During the later outbreaks in Bangladesh a d India, Nipah virus spread directly from Human - to humans through close contact with people's secretions and excretions. Transmission of the virus was also reported within a healthcare setting, where 75% of cases occurred among hospital staff or visitors. Around half of reported cases in Bangladesh were die to the human-to-human transmission through providing care to infected patients.
Signs and symptoms:
Human infections range from asymptomatic infection to acute respiratory infection (mild, severe) and fatal encephalitis.
Infected people initially develop symptoms including 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.
The incubation period is believed to range from 4 to 14 days. However, an incubation period as long as 45 days have been reported.
Most people who survive acute encephalitis make a full recovery, but long-term neurological conditions have been reported in survivors. Approximately 20% of patients are left with residential neurological consequences such as seizure disorder and personality changes. A small number of people who recover subsequently relapse or develop delayed onset encephalitis.
The case fatality rate is estimated at 40% to 75%. This rate can vary by outbreak depending on local capabilities for epidemiological surveillance and clinical management.
- Fever
- Headache
- Muscle Pain(Myalgia)
- Vomiting
- Sore Throat
These symptoms can be followed by more serious conditions including:
- Dizziness
- Altered consciousness
- Acute encephalitis
- Atypical Pneumonia
- Severe Respiratory
- Seizures
Diagnosis:
Initial signs and symptoms of Nipah virus infection are nonspecific, and the diagnosis is often not suspected at the time of presentation. This can hinder accurate diagnosis and creates challenges in outbreak detection, effective and timely infection control measures, and outbreak response activities.
In addition, the quality, quantity, type, timing of clinical sample collection, and the time needed to transfer samples to the laboratory can affect the accuracy of laboratory results.
Nipah virus infection can be diagnosed with clinical history during the acute and convalescent phases of the disease. The main tests used are real-time polymerase chain reaction from bodily fluids and antibody detection via enzyme-linked immunosorbent assay (ELISA). Other tests used include polymerase chain reaction (PCR) assay and virus isolation by cell culture.
Treatment:
There are currently no drugs or vaccines specific for Nipah virus infection although WHO has identified Nipah as a priority disease for the WHO research and development Blueprint. Intensive supportive care is recommended to treat severe respiratory and neurological complications.
