On June 30, a 18-year-old woman died allegedly due to rabies in Kerala’s Thrissur. The same day, a 60-year-old man also succumbed to the virus. The cases were similar since but one of them died after getting vaccinated. TNM spoke to doctors to know about the virus, its behaviour, exhibition of symptoms and how to prevent an infection.
Before delving into the details, this is what happened: The woman named Srilakshmi was bitten by her neighbour’s dog on May 30, when she was on her way to college. She took four shots of anti-rabies vaccine and did not exhibit any symptoms, up until two days before her death. She was first taken to a private hospital and later admitted at the Thrissur Medical College with high fever, where the doctors stated that she had symptoms of rabies. She passed away on June 30. The pet dog that bit Srilakshmi had also bitten its owner on May 29, but his condition is said to be stable as of now.
In the case of the sexagenarian named Unnikrishnan Puthukkattil, the dog bite incident happened three months ago. The dog died soon after. He started exhibiting symptoms of rabies a few days ago and was admitted to the same hospital as Srilakshmi, and passed away last night. However, he was not vaccinated, according to reports.
According to the World Health Organisation, “rabies is a viral zoonotic disease that causes progressive and fatal inflammation of the brain and spinal cord.” It has two clinical forms: furious rabies, which is characterised by hyperactivity and hallucinations; and paralytic rabies, characterised by paralysis and coma, as specified in the name. The virus causing the disease is a member of the Lyssavirus genus.
Speaking to TNM, Dr TR Radha, Professor and Head of Department of Medicine in Thrissur Government Medical College said the virus may spread to humans through saliva from various groups of animals, including canines, and felines. “In Western countries, we also have instances of the virus being transmitted from bats,” she said. While household rats pose lesser threat, chances are there that wild rodents may transmit the virus.
“So as I said, the transmission of virus happens from the saliva of these animals, when they bite, lick, or through breaks in our skin, or oral cavity, that is when we kiss the pets. However, the problem here is that many of these animals are silent carriers of the virus and may not even show symptoms but when they bite a person, the person may get the disease,” she said.
“Every contact with these animals is categorised depending on the site of the bite, whether it is occurring on an intact skin or broken skin, or whether it is in the oral cavity, or parts like neck, face, etc. The closer the site is to the brain the higher the risk of viral transmission to the brain, because basically the disease mainly affects the brain. Also, bites on fingers are equally dangerous. From these areas, the virus will retrogradely migrate to the brain,” says Dr Radha.
She further explains that there are three categories of exposure or contact with an animal with the virus. Category I includes touching or feeding animals, or the animal licking on intact skin. Category II includes minor scratches or abrasion in the skin but no blood is drawn. Category III is bites, scratches, saliva entering the broken skin, etc.
“While category I does not necessarily require the patient to get vaccinated, the other two categories must be vaccinated and treated appropriately. And if we don’t know which animal has bitten us, that is if it bites you and runs away, it is always considered as category III exposure, which is the severest form of the bite,” she adds.
Speaking about the symptoms and the time taken for it to be expressed, especially in these cases where it took from weeks to months to find out about the infection, she says that symptoms can start anywhere between a week to years after a bite. Some reports are there which say that eight years after a bite being forgotten by the patient, they started having symptoms of rabies, she added.
“The symptoms depend on three factors. One is the site of the bite; two, viral load, that is volume of the virus that went inside our body; and three, immunity status of the individual. If the person is immunologically compromised, they carry a very high risk of the virus multiplying and producing the disease. So, factors are variable when it comes to producing a disease,” she says.
According to WHO, the incubation period for rabies is stated as two to three months, but may change “from 1 week to 1 year” depending on several factors.
Dr Radha says that the first symptom exhibited is a form of tingling in the wound. Initial symptoms are very non-specific, like fever, bodyache, headache, etc, so the people do not even realise that it is rabies.
“The next phase is when we really diagnose the disease, through the classic symptom of hydrophobia (fear of water) and sometimes aerophobia (fear of drafts or of fresh air). When the patient sees water, their throat tightens up and the whole muscles go into spasm. This is the second stage of the disease, which tells us that the disease has already been established. It becomes very difficult to treat at this stage,” she says.
In the last stage of the disease, Dr Radha said the patient goes into an agitated delirium, and can develop fits and also altered behaviour. They may try to bite others, they may have foam forming in their mouth. “So, at this stage, rabies is established, and is considered the terminal stage of the illness. Once it has gone to the established stage, it is 100% fatal. However, there are few cases where the patients have survived after this stage with intensive care and treatment, but none of the survivors were normal. That is, all of them had some form of disability, and most of them were bedridden and they all died later. So, after this stage, survival does not mean normal life,” she says.
As for the question of vaccine efficacy, Dr Radha says that there are different types of vaccines available and of late, intradermal vaccination (delivery of vaccines into the outer layers of the skin) is given, which has proved to be 100% efficient. She also says that there is no question of ‘should we take the vaccine’, because not taking them makes the viral disease fatal.
According to the ‘rabies vaccines: WHO position paper 2018’, rabies is considered to be a vaccine-preventable disease in both humans and animals. The paper also says that “vaccination of humans is an effective preventive intervention” before or after exposure to the virus. “rabies vaccines are highly effective, safe and well tolerated,” the paper concludes.
The paper also directs that the first dose of rabies vaccine should be immediately administered after exposure, as soon as possible. Also, the vaccine should compulsorily be taken in case of category III exposure to virus, ‘even months or years after the contact’. It also points out that the possibility of developing rabies “declines progressively during the 12 months after the exposure” and it occurs rarely after 12 months.
In case of a bite, these things are to be done. This is also called Post-exposure Prophylaxis (PEP):
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* Rabies Immunoglobin (RIG) is also called anti-rabies serum, and is a readymade antibody which provides passive immunity to the victim, as it may take some time for the person’s body to produce antibodies of their own.
When Dr Radha was asked if it was possible that a person can exhibit symptoms or if it can lead to death even after getting vaccinated, she said, “some people may not develop enough antibody response after the viral vaccination. Why this happens has to be studied, that has to be undertaken as a general study. However, whatever be the situation, vaccination has to be done because once the disease reaches the established stage, there is no treatment for it and it is 100% fatal”.
Dr Prem Kumar, District Medical Officer, Thrissur said that such cases of death and severe disease are reported only with those who are not vaccinated. “However, there is a sufficient stock of vaccines and a detailed probe is underway in this case,” he said.
Regarding prevention of rabies in animals, Dr Nataraja Kumar, Joint Director of Animal Husbandry in Madurai, says that vaccination is the only effective way, as the animals might even serve as carriers. “So no matter if it is a pet animal or a stray one, it is recommended to get vaccinated as soon as there is an exposure to the saliva of the animals, either through bite or a break in our skin. As far as animals are concerned, they should be given the periodical vaccination without fail, as chances are less for the animals to get the virus, if they are vaccinated,” he says, and adds that the common symptom to watch out for is sudden ferocity in animals.
A report by the World Organisation for Animal Health says that there is no treatment for rabies in animals once the clinical signs appear. However, it can be prevented by vaccination and by avoiding contact with rabid animals. In animals that are vaccinated, only rare cases have been infected, the report says.
According to the National Action Plan for Dog Mediated rabies Elimination from India by 2030, “rabid animals of all species commonly exhibit typical signs of central nervous system disturbances with behavioral changes.” The report also points out that nearly 97% of the rabies cases are most commonly transmitted through dogs and cats In India.
The report also gives us the symptoms and incubation period to be borne in mind.
Dogs
Cats
Cats also exhibit the same symptoms, but the report also suggests that cats “have a greater tendency to hide in secluded places and are more vicious than dogs”.
Speaking to TNM, Dr Pawan Kumar, Senior Surgeon at Cessna Lifeline Veterinary Hospital, says that there is no treatment for rabies in animals. “The animal must be isolated and euthanasia is preferred, to protect other humans and animals,” he says. There is little chance of an animal vaccinated properly contracting the virus, especially pets vaccinated at the prescribed schedule, he said.
He also said that a vaccination schedule is followed in India. “According to it, a rabies primary vaccination is inoculated at three months of age of the animal, which is followed by a booster dose within three to four weeks. And then annually one dose of vaccination,” he explains.
The National Guidelines for rabies Prophylaxis, 2019, released by the Ministry of Health and Family Welfare (MoHFW), says that vaccinated animals, in general, do not suffer from or transmit the disease. However, there might be failures in the vaccination procedure due to “improper administration, inadequate doses, poor vaccine quality or poor health of animals”. So the report concludes that an animal even with a vaccine history cannot be considered that it is not rabid.