Nipah Virus (Representation Only)

Nipah virus is a zoonotic virus (it is transmitted from animals to humans) and can also be transmitted through contaminated food or directly between people. Nipah virus belongs to a genus of paramyxoviruses (Henipavirus), including the highly pathogenic Hendra virus found in Australia with mortality rates in excess of 70%.

Since its first detection in Malaysia, a closely related Nipah virus has emerged in Bangladesh/ India region since 2001. Pteropus bats (fruit eating bats) are likely the main animal reservoir for Nipah virus, although there is evidence suggesting that other bat species are also susceptible to Nipah virus infection in nature.

Studies have shown that the virus can be transmitted to human by three different routes:
1. From bats to humans who come in contact with virus-contaminated material (e.g., date palm sap);
2. From intermediate hosts such as pigs and horses; and
3. From infected humans.



Diagnosis:

Molecular tests (both qPCR and next generation sequencing) are the most rapid and accurate tools available to confirm Nipah virus infection. Acute-phase serum, CSF, throat swabs, saliva, and urine can be used for these tests. There is also an IgM ELISA test based on whole viral antigen.

Signs and symptoms:

1. In infected people, it causes a range of illnesses from asymptomatic (subclinical) infection to acute respiratory illness and fatal encephalitis. The virus can also cause severe disease in animals such as pigs, resulting in significant economic losses for farmers.

2. There is also epidemiological evidence that companion animals (including dogs and cats) can be infected with these viruses and they can in theory transmit viruses to humans as well. Clinical symptoms include fever and headaches, which can progress to drowsiness, disorientation, mental confusion, and finally encephalitis (brain swelling) in less than a week.

Treatment:

1. Currently there is no effective treatment for Nipah virus infection. The treatment is limited to supportive care. It is important to practice standard infection control practices and proper barrier nursing techniques to avoid the spread of the infection from person to person. All suspected cases of Nipah virus infection should be isolated.

2. Ribavirin has been studied in a small number of people, however whether or not it is useful is unclear as of 2011. Passive immunization using a human monoclonal antibody that targets the Nipah G glycoprotein has been evaluated in the ferret model as post-exposure prophylaxis. The anti-malarial drug chloroquine was shown to block the critical functions needed for maturation of Nipah virus, although no clinical benefit has yet been observed. m102.4, a human monoclonal antibody, has been used in people on a compassionate use basis in Australia and was in pre-clinical development in 2013.

Outbreaks:

1. Nipah virus outbreaks have been reported in Malaysia, Singapore, Bangladesh and India. The highest mortality due to Nipah virus infection has occurred in Bangladesh. In Bangladesh, the outbreaks are typically seen in winter season. Nipah virus first appeared in Malaysia 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. In 2001, Nipah virus was reported from Meherpur District, Bangladesh and Siliguri, India.The outbreak again appeared in 2003, 2004 and 2005 in Naogaon District, Manikganj District, Rajbari District, Faridpur District and Tangail District. In Bangladesh, there were also outbreaks in subsequent years.

2. In May 2018, an outbreak was reported in the Kozhikode district of Kerala, India.Seventeen deaths were recorded, including one healthcare worker. Those who have died were mainly from the districts of Kozhikode and Malappuram, including a 31-year-old nurse, who was treating patients infected with the virus. Two of the infected were completely cured. On June 10, 2018, the outbreak was officially declared to be over.