'Without Anti-Rabies Vaccine, Dog Bite Can Leave Its Victim ‘Barking’’

  'Without Anti-Rabies Vaccine, Dog Bite Can Leave Its Victim ‘Barking’’

Professor Daniel Oluwayelu, a virologist and the immediate past Head, Department of Veterinary Microbiology at the University of Ibadan, in this interview by SADE OGUNTOLA, says rabies is a disease that is not receiving the desired attention in Nigeria even though it kills faster than many diseases including TB and HIV/AIDS.

How common is rabies in Nigeria; why should there be talks about it now?

Rabies is a zoonotic viral disease. It is caused by the rabies virus that affects all warm-blooded animals, including humans. These animals are especially carnivores like dogs, cats, and foxes. In the United States of America, raccoons and skunks are also reservoirs of the disease. In addition, it can be transmitted by bats.

Rabies is a grossly underreported zoonotic disease that is endemic in poor communities especially in Africa and Asia. It is classified as a neglected zoonosis because it is not receiving the much-needed attention, in terms of prevention and control efforts that it is supposed to receive. In recent times, diseases like COVID-19, Avian Influenza, Swine influenza, and Ebola seem to have taken over the air waves, relegating rabies to the background. As a result of the high morbidity and mortality caused by these other diseases, more attention is given to them by government agencies and funding organisations compared to rabies. Meanwhile, rabies is silently causing more damage.

Deaths from dog rabies on an annual basis are put at about 60,000 globally. Data on the true number of deaths from rabies in Nigeria is lacking. The disease is not restricted to any region in Nigeria; it is cosmopolitan in nature.

As long as reservoir hosts of the virus are present in any community, it will continue to be transmitted to humans and we will still be having cases of rabies. The unfortunate thing is that most reservoirs of rabies virus are friends of humans, especially dogs and cats. Even domestic animals such as cattle and pigs have been infected with the virus. We also have a lot of stray or homeless dogs roaming our streets with most of them being unvaccinated and constituting a huge risk to the human population. So, rabies is not a disease we should sweep under the carpet.

Can rabies be contracted from the saliva of an infected animal when one is exposed to such dogs or cats?

Yes, rabies is majorly transmitted to humans through bites of animals that serve as reservoirs for the virus. Since the saliva contains large quantities of the virus, it can easily be transmitted to such individuals. That is why it is advocated that owners of dogs and cats should vaccinate them. Rabies cannot be contracted through blood.

Rabies is one of those diseases that are classified as bedroom zoonoses which are reported, especially in advanced countries, where people maintain very close relationships with their pets, even kissing and sleeping on the same bed with them. Since the virus is transmitted through saliva, they can easily get infected. Also, due to the growing insecurity in Nigeria, many individuals now keep dogs as guards. Likewise, local hunters still maintain their hunting dogs that are exposed to wild animal reservoirs of rabies. So, as long as people keep these animals, including cats, they should endeavor to vaccinate them against the disease annually. This cannot be overemphasised so that the risk of human exposure to rabies can be reduced.

Is it possible to contract rabies through having sex with a dog? Recently in the media, there were reports of ladies having sex with dogs for monetary rewards.

Although sex with animals is not acceptable, such ladies cannot contract rabies through this avenue. Rabies is not sexually transmitted. It cannot also be transmitted by blood, urine, or faeces of an infected animal. The main route of exposure to the virus is through the saliva or bite of infected dogs, cats and other animals, including bats. Unvaccinated people, especially children, should be discouraged from going into caves where bats roost because that is a very good way of getting exposed to the virus.

How deadly is rabies; can it kill as fast as say malaria, TB, or even HIV/AIDS?

Rabies kills very fast, faster than all these diseases. Rabies virus has affinity with the nervous system. Once it enters the body through a bite on the leg, arm or face, it moves straight to the nervous system and ascends from the peripheral to the central nervous system, that is, the brain. This may take between few days to some weeks, depending on how close the site of bite is to the brain and the quantity of virus deposited in the individual at the time of bite. So, rabies kills faster than HIV/AIDS or TB which may take months or even years before the individual starts manifesting the typical symptoms. Therefore, it is not something we should underestimate at all.

Is it possible to identify an animal that is infected with rabies?

Yes, it is. There are two forms of dog rabies based on its clinical manifestations. There is the furious rabies and the dumb or paralytic rabies. With the dumb rabies, a usually aggressive or wild dog suddenly becomes docile, calm and unusually affectionate. Also, there may be copious salivation and the animal may exhibit paralysis or lameness.

With furious rabies, a previously friendly and calm dog becomes restless, aggressive and starts barking at almost everything in sight, including rocks and trees. Generally, the dog finds it difficult to swallow and there is excessive salivation, hydrophobia (fear of water), staggering, sensitivity to light and/or self-mutilation.  There is a rapid test that can be used to detect rabies virus antigen in the saliva of infected animals. But generally, a conclusive diagnosis for rabies is by laboratory confirmation using the brain obtained from a dog that dies of the disease.

In local parlance, it is said that a person who is bitten by a rabid dog also ends up barking like a dog. Is this true?

Well, not barking in the real sense of the word but there may be abnormal vocalisation or abnormal sounds from the person. Other symptoms in humans include hydrophobia, photophobia, insomnia and paralysis.

Can an individual survive rabies disease or a bite from a rabid dog?

Although rabies is a highly fatal disease, individuals bitten by rabid dogs can survive if they receive what is known as post-exposure prophylaxis (PEP) within 10 days of the bite. The PEP involves administration of human rabies immunoglobulin and about four doses of rabies vaccine which will help boost the immune system so the body can eliminate the virus. However, if no PEP is given and the virus gets into the brain, there is no reversal; it is only a matter of days before the individual dies.

The disease is not new, so why do we still have rabies?

Rabies is still around because we have not prioritised vaccination of dogs and cats which constitute over 90 per cent of animals that transmit the virus to humans. Vaccination against rabies should be done routinely. Puppies are supposed to be vaccinated at three months and then followed up with annual booster doses. The government should actually enforce that policy. There is something that is called responsible dog ownership which involves keeping your dog happy, healthy, and safe by taking care of their basic dietary, medical, physical, and psychological needs. In some developed countries, you are not allowed to keep dogs except you have been proven to be responsible, and vaccination of those animals is very crucial. The owner of a vaccinated dog is issued a certificate. In some climes, a vaccinated dog is also given a special collar which is worn on its neck. Animals without such collars are taken off the streets.

In addition, since rabies is endemic in Nigeria, sustained public health awareness about the disease such as we had for Ebola virus disease and now have for COVID-19 will help reduce occurrence of the disease apart from vaccination and its enforcement.

Being an expert in rabies, can you assess Nigeria’s surveillance system for rabies?

Nigeria’s surveillance for rabies is suboptimal; we need to up our game in routine surveillance not only for rabies but for quite a few other diseases.  We need to be ahead of this virus; we need to know how it is evolving and areas where the dog population have no antibodies or suboptimal antibodies to this virus. Then we can move in to conduct mass anti-rabies vaccination campaigns, which will help to curtail its spread.

Nigeria is said to be the third-highest consumer of dog meat in the world. Should this be of concern considering the fatality of rabies?

Quite a number of ethnic groups eat dog meat in Nigeria. In fact, it is a delicacy in some food canteens. This is of concern because most dogs used for this delicacy, called Isi-Ewu, always look rough, and unhealthy. Most are likely to be stray dogs just taken off the streets and slaughtered for consumption. These dogs could become aggressive and attack their captors; they may bite them and in the process transmit the virus through saliva to them. So, this practice is a huge public health concern that needs to be addressed immediately too.

Some zoonotic diseases spread from human to human. Is human-to-human transmission of rabies possible?

No, as far as I know, human-to-human transmission of rabies has not been established or documented.