A climate of fear emerges in the northern part (Kozhikode) of southern Indian State (Kerala) after the death of at least ten people who have been infected with Nipah virus.
Should we be worried about the current Nipah virus outbreak?How to prevent further spreading of this virus and be safe?
Disclaimer: As per the initial news, the outbreak in Kerala was thought to be from bats that were found inside the well of the infected peoples house. But now as lab tests conducted on the bat and pig samples collected from in and around the affected area turned out negative, the source of the outbreak is yet to be found out. As the source remains a mystery, it is wise to have a good knowledge about the disease, its normal transmission mode, symptoms and characteristics and take precautions accordignly.This article is to spread awareness about the Nipah Virus and help people take proper safety measures as per standard guidelines.
Let us see all these in detail here all about Nipah virus as the best way to prevent it from spreading further is by taking precautions and being alert.
What is Nipah Virus (NiV)?
For the past two weeks, we have been hearing so much of this Nipah Virus through news and other social platforms.
Nipah Virus is zoonotic (refers to the ability to cause disease from animals to humans ), highly contagious and causes utmost fatal disasters.
They are single stranded RNA enveloped viruses of the family Paramyxoviridae(genus: Henipavirus) which is more or less similar to Hendra virus. There are two pedigrees found so far; a Bangladesh strain (bNiV) and a Malaysian strain (mNiV).
This virus contains two major membrane-anchored envelope glycoproteins that are required for infection into a host cell.
When and How Nipah Virus Was First Identified?
The Nipah virus(NiV) was identified in a person from Kampung Sungai, Nipah village of Malaysia in 1998-1999. The virus is named after the village name.
Most of the patients during that outbreak were the workers in pig farms who had contact with ill pigs. Lot of fruit trees were grown in these pig farms where bats could drop down the half-eaten fruit in the pig stalls. These fruits could be contaminated with NiV. When the pigs eat the fruit, they become infected with NiV, and transmit virus to other pigs in the farm and from pigs to humans who take care of pigs.
Source or Reservoir of Nipah Virus
Fruit bats (genus: Pteropus = flying foxes) are found to be the natural reservoir for its survival. It can be spread to humans when fruit pulp spat out by bats are consumed.
In the past outbreaks in Malaysia, the disease had spread from bats to pigs and then to humans.
Few characteristics of Nipah Virus you should know
- This virus generally opts to stay inside the bat’s body. Only under favourable conditions it enter into the host body for its replication.
- Favourable temperature for this virus to survive is 22 degree Celsius to 37 degree Celsius.
- It wants an acidic pH of 2-5 to survive. It can’t live on alkaline condition.
- If the pH is alkaline say 7 and above, it can’t survive. Under this pH its cell membrane burst out and it will die. So, washing your hands with a good sanitizer will help you to control its spread during this outbreak time.
- When Nipah Virus infest into fruits eaten by bats, it can live inside the fruits for up to 4-5 days because of the acidic and fructose medium in the fruits.
- This virus can be alive in the human body for months without showing any symptoms and later it can reactivate itself
Who Is At High Risk Of Nipah Virus Exposure?
- Humans those working with pigs
- Farmers who come in contact with bats
- People who consume fruits which are spat out by bats
- People who contact with other humans infected with Nipah virus in public places
- Caretakers of patients who are infected with Nipah virus
Nipah Virus Symptoms in humans
Once a person is infected by the virus,the symptoms can appear within 4 to 14 days. Patients will show one or two symptoms or all of the below
- Sudden onset of fever
- Muscle pain
- Neck rigidity
Initial symptoms progress to impaired consciousness leading to coma within five to seven days.
More importantly, as Nipah can cause meningitis it results in disorientation and mental confusion.
If symptoms are seen in people close to you quarantine them immediately and take them to the hospital with proper personal protective measures (PPE).
Mode of Nipah Virus transmission to humans
In India, annual outbreaks do occur and so far, it’s found out that Nipah virus transmission occurs mainly in four modes
- Bats-to-pig transmission
- Bats-to-human transmission
- Pigs-to-human transmission
- Human-to-human transmission
Pigs and humans are considered to be the most common host for Nipah Virus to reproduce and multiply. Horse, dogs, cats, and monkey are susceptible but are not thought to be involved in transmission.
Bats to pig transmission happens
- If the virus-contaminated fruit pulp spat out by bats are eaten by pigs.
- When pigs ingest the infected fecal tissues of bats.
- When the urine from bats contaminates grazing land or pigsty.
Bats-to-human transmission is mainly caused by drinking of raw date palm juice which is contaminated with fruit bat excretions or by eating the bat-bitten fruits contaminated with Nipah Virus.
Pig-to-human transmission is believed to be transmitted via sputum or faeces of pigs.
Transmission of Nipah virus from human to human may occur via direct contact or possibly dispersed as aerosol. Human-to-human transmission of Nipah virus is regularly seen in the members of same family or the care providers of Nipah virus-infected patients.
Mechanism of Nipah virus transmission
To be noted, Nipah virus never cause disease in bats because it has immunity to the pathogen. Once they find promising conditions to replicate, Nipah Virus gets transmitted to intermediate hosts like pig or humans via body secretions.
Humans and pigs are mainly selected for their replication because of the cell receptors of the receptive hosts in which the pathogen perfectly fits in.
The accurate mechanism of Nipah virus transmission from bats to humans is not clearly understood till date. Exact studies can’t be done in this area because Nipah Virus are considered as biosafety level (BSL) 4 agents. The Center of Disease Control (CDC) has announced Nipah Virus as a biosafety level 4 agent, the highest biosafety level class.
BSL 4 agent are agents which can be distributed via aerosol transmission and which has no proper treatment or vaccines found so far. Moreover, any infectious related experiments have to be carried on in BSL4 facilities laboratories by skilled and highly trained microbiologists.
Out of many experiment findings, one of the main hypothesis regarding molecular mechanism of Nipah virus transmission is found to be through fomites.
Now what are fomites?
Fomites are nothing but those non-living objects which acts as vectors to carry infectious material to the host. It is still unknown how long the virus can survive outside a host. The assumption is that it can survive maximum up to 15 minutes or so outside a host body.
Once Nipah Virus infest into human body, it travels straight to the tonsils. Incubation period is 5-14 days in tonsils and the replication occurs in the tonsils and it multiplies.
From there it passes to respiratory tract and causes inflammation over there. This leads to cold, cough and fever like symptoms. Then within hours it will enter into blood vessels. At the later stage it will start replicating in brain leading to encephalitis and show symptoms like vomiting, unconsciousness and coma. This will finally result in myocarditis.
Diagnosis of NiV
As mentioned earlier, handling Nipah Virus requires an advanced BSL4 biosafety level laboratory,
In India the diagnosis is carried out at two institutions; National institute of Virology, Pune and Manipal Centre for Virology and Research. These two institutions are equipped with the required advanced BSL 3 lab to deal with Nipah Virus.
Laboratory diagnosis of a patient infected with Nipah Virus can be done during the acute and recovering phases of the disease by using a combination of tests.
Nasal swabs, throat swabs, urine, blood and cerebrospinal fluids should be performed in the early stages of disease. Later on, antibody detection by ELISA (IgG and IgM) can be done.
In fatal cases, immunohistochemistry on tissues collected during autopsy may be the only way to confirm a diagnosis.
Prevention and Control Of Nipah Virus
Prevention is the only cure to limit the spread of Nipah virus infection.
Ways To Prevent And Control Nipah Virus
- Maintain personal hygiene and intensive hand washing practices
- Avoid contact with pigs and pig handlers
- Do not eat raw fruits and vegetables those fallen on the ground. This could be contaminated by bats secretions
- Avoid using toddy or palm sap as there are chances of these to get contaminated by bats
- Wash fruits and vegetables thoroughly in salt water before consumption
- Consume only well cooked, clean, homemade food (be it vegetables, eggs or meat) till the outbreak settles down
- Keep your home and surroundings clean
- Clean and cover up wells or other water reservoirs in your house to avoid bat’s urine to drop in.
- Preferably use N95 mask (not surgical mask) while treating Nipah infected patients, travelling or in public places to avoid person to person transmission
- Keep the things used by the patients separately like clothes, bedsheets, utensils and wash those in hot water
- Be aware of the symptoms and report to the doctor immediately for early diagnosis and treatment, so that they can make arrangements for the isolation ward and other precautionary actions
- People working in health care, wear your Personal Protective Equipment (PPE). PPE includes N95 mask, gloves, head mask, gown and boots.
How it affects pregnancy?
No case studies regarding Nipah Virus and human pregnancy have been done.
In utero mother-to- fetus transmission of viruses can happen within the host and also can be transmitted to other hosts.
There are two possible ways of transmission to fetus happens, if the pregnant mother is infected with Nipah Virus
- Mother-to -fetus in-utero transmission
- Transmission during delivery
Viral spread may occur in a pregnant lady through close contact between infected maternal tissue and sensitive fetal tissue. But the virus has to cross the placental barrier between the mom and foetus to infest. So, this way of transmission will be very difficult to happen.
The other possibility is that infection to the baby may happen during delivery, when the placental barrier between mom and child is removed.
Treatment For Nipah
No vaccines have been developed against this virus. This is because Nipah Virus contains an RNA structure, that means it can alter its structure accordingly once in human body. This could result in a poor binding of the vaccines to the antigen.
A Supportive care and intensive care monitoring of the infected patients is the only treatment as of now.
A word of caution to parents
Its summer holidays and mango season in India. So, kids are going to pick mangoes and eat it. If these mangoes were bat bitten, there is a very high possibility for the kids to get infected with Nipah virus. The infected kids thus carry the virus to their home and spread it to the adults. So, advice kids not to pick and eat fruits. Ask them to wash thoroughly before having any type of fruits.
Rumor spread in social networks
I am mentioning here some of the randomized rumor spread in social media that I have come across recently
X Broiler chickens and cattle were infected with Nipah Virus
X Don’t drink cow’s milk
X Don’t eat chicken and meat
X Don’t eat fruits and vegetables
X Don’t drink well water
All these informations are baseless.
I would like to share with you some facts regarding this. When you properly cook meat or pork, the cooking temperature (more than 70 degrees Celsius) is going to kill the pathogen if its contaminated also. As mentioned earlier Nipah virus can only survive under the temperature 22-37 degrees Celsius.
Now coming to the well water rumor, as I told earlier Nipah virus can only survive in acidic pH (between 2-5). Our well water and other water reservoirs hold a pH of more than 7. So, this virus can’t survive in the well water much time. To be more on safer side, always boil and drink the water and cover up your wells to avoid dropping in the bat-bitten fruits or its urine.
If you are going to avoid all these foods like milk, fruits, vegetables, meat etc., your immunity is going to drop down for sure. This might make your body to fight less towards the pathogens and make you more susceptible to other type of diseases.
These all are just rumors spread by those who had zero knowledge about this virus.
Don’t ever share or forward these types of unhealthy posts and make the stressful situations more panicky.
So, stamp out this type of rumors and start consuming well washed/boiled/cooked fruits, vegetables, milk and meat.
Follow the instructions given by the government authorities or visit WHO site for correct preventive measures and precautions.
It is of extreme importance to control the virus and stop an epidemic. Till now, there are no specific vaccines or drugs that target the virus specifically, so prevention is the best way to protect us from Nipah Virus. Don’t panic as the preventive measure are being put into place by our government. So, stick on to the precautionary measures and everybody stay safe!!
Footnote: It was such a heartache to know Lini Puthussery, the nurse and a mom of two toddlers lost her life while treating Nipah Virus infected patients. We, bumps n baby team, paying our respects to her and hope that their family members find the strength to bear on. What an extraordinary human and a mother! RIP Lini!!
We salute the nurses and doctors who are working day and night to treat the infected onces risking their own lifes.