Nipah virus: An intractable disease

INTRO: A rare but deadly virus that may infect humans and cause fever, vomiting, and respiratory ailments is carried by bats

BLURB: The World Health Organisation has designated the Nipah virus as a priority disease because of its ability to spread like an epidemic and its estimated 40–75% fatality rate.

The bat-borne Nipah outbreak in Kerala has infected six people — two of whom have died — since it emerged in late August. Approximately 700 people, including healthcare workers, have been tested for infection over the past week.

Experts are concerned that increased human spread of the virus will make it more contagious, despite the fact that such outbreaks normally affect a small geographic area.

Nipah virus is another zoonotic virus that can spread from animals to humans. Fruit bats, which are predominantly found in the Nilgiris, are known to be the virus’ reservoirs.

Since its discovery in late August, the bat-borne Nipah outbreak in Kerala has infected six people, two of whom have died. Over the last week, around 700 people, including healthcare personnel, have been tested for illness. Despite the fact that such outbreaks typically affect a narrow geographic area, experts are afraid that greater human circulation of the virus will make it more contagious. Another zoonotic virus that can transfer from animals to humans is the Nipah virus. Fruit bats, which are common in the Nilgiris, are known to be viral reservoirs.

The worrying factor

Dr. Rajiv Bahl, the Director General of the Indian Council of Medical Research (ICMR), provided important information about the Nipah virus, highlighting its high death rate and differentiating its transmission characteristics from those of Covid-19. Dr. Bahl underlined that a significant mortality rate of 40% to 70% is associated with the respiratory droplet-transmitted Nipah virus. “The most worrisome thing is that Nipah has a far greater fatality rate and is 70–80 times deadlier than SARS-CoV-2. In recent times, Bangladesh had a mortality rate over 70%, whereas Malaysia had a rate between 30 and 40%. Only two people survived the 23 incidents that occurred in Kerala in 2018 (91% fatality rate)," according to Dr. G V Rao, Director & Chief of Gastrointestinal & Minimally Invasive Surgery, Asian Institute of Gastroenterology.

Transmission to humans

Either human-to-human or overflow transmission from bats causes human infection. According to Dr G V Rao, "there are two mechanisms through which spillover transmission from bats can occur: direct bat-to-human transmission (interaction with bats or their secretions, intake of raw date palm sap [tari] contaminated by bat saliva), or indirect transmission from bats via an intermediate animal host.".

“In the 2004 Bangladeshi outbreak, 33 of the 36 confirmed cases had previously had close contact with another infected patient; this further demonstrated the importance of human-to-human transmission. According to Dr. K Subba Reddy, a critical care specialist at Apollo Health City, the median incubation period for Nipah virus infection brought on by contact with an infected patient was nine days (range, 6 to 11 days). A medical professional who treated a patient afflicted with the virus was among the fatalities in this most recent epidemic in Kerala..

Signs & symptoms

“The most typical sign of the virus-caused illness is encephalitis, or swelling of the brain. Many patients experience confusion, drowsiness, and disorientation in addition to developing a temperature and excruciating headaches. A chest infection has a high mortality rate and is also experienced by certain people. Nevertheless, some individuals may remain asymptomatic, according to Dr. G. V. Rao, who also notes that symptoms usually appear four to fourteen days after exposure. The symptoms of the virus are similar to many other conditions, making early identification difficult, according to the Centres for Disease Control and Prevention (CDC). Confusion, drowsiness, convulsions, or encephalitis—a brain infection—are among the virus's severe symptoms. According to the CDC, these can cause a coma to form in 24 to 48 hours..

•Fever

•Headache

•Myalgia

•Dizziness

•Altered consciousness

•Acute encephalitis

•Atypical pneumonia

•Severe respiratory distress

•Seizures

Diagnosis

A definitive diagnosis of Nipah virus infection requires the presence of the virus in bodily fluids (such as tissue samples, blood, urine, and cerebrospinal fluid), as well as swabs from the throat and nose. "Virus isolation is not frequently carried out since the Nipah virus is classified as a biosafety category 4 agent. Other methods, including serology or polymerase chain reaction (PCR), are therefore being employed more frequently, according to Dr. Subba Reddy..

Treatment

Medical care is only "supportive," meaning that it concentrates on treating the patient's individual symptoms and keeping them comfortable until they eventually recover, because the Nipah virus cannot be directly treated with drugs. "The mainstay of treatment is supportive care; patients with infections may also need to be monitored in intensive care. As soon as neurologic impairment manifests, airway preservation with mechanical ventilation should be initiated. The only post-exposure medication that has proven effective against Nipah to date is the human monoclonal antibody (mAb)-m102.4. The vaccines are being developed, and we anticipate having them available for use by the general population shortly,” says Dr Subba Reddy.

Prevention

* Should be advised to steer clear of raw palm sap that can be contaminated in order to reduce the risk of bat-to-human transmission; however, this can be difficult and requires consideration for regional traditions and beliefs.

* Should avoid close, unprotected personal contact with patients who are infected with the Nipah virus and wear gloves and other protective clothing when handling ill animals or their tissues.

* Healthcare professionals should take contact and droplet precautions in addition to standard infection control measures when caring for patients with suspected or confirmed infections or handling their specimens.

BOX

Nipah virus outbreak

* In 1998 and 1999, the Nipah virus created an outbreak in humans and pigs in Malaysia and Singapore. Since then, the virus has often caused outbreaks in Bangladesh, West Bengal, and Kerala. There were other outbreaks in Kerala, India in 2018 in the Philippines in 2014.

* The affected patient lived in a hamlet in Malaysia, which inspired the name of the virus.

HIGHLIGHT

Since there is no specific drug to treat the Nipah virus, medical care is solely "supportive," meaning it addresses the patient's individual symptoms and keeps them comfortable until they eventually recover.