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What I know about viruses

Health & Science

Viruses are everywhere. Some are lethal, others harmless. Humanity is currently in the throes of a pandemic caused by a virus. Prof Matilu Mwau, who has had 20 years’ experience as a virologist, medical doctor and a research leader, shares what he thinks we should all know about viruses.

As told to Jacqueline Mahugu

1.  First things first, let’s set straight a few untruths being peddled around:

·         There aren’t foods with certain PHs that are better for fighting coronavirus than others. The alkalinity or acidity of food does not make a difference regarding your susceptibility to Covid-19.      

·         5G networks do NOT cause Covid-19. The coronavirus is a virus while 5G is a technology. 5G technologies do not affect the immune system, as immune systems do not work like technology. 5G systems do not transmit viruses.

·         Bill Gates donates money to GAVI (Global Aids Vaccine Initiative) so that countries like Kenya can get essential vaccines cheaply. He is not introducing any vaccine of any kind and he is not implanting microchips of any kind through vaccines.

·         Sars Coronavirus 2 was not released from a lab in Wuhan. We can tell the route that it used to jump from animals to humans, and to get where it is right now. The lab is not part of that story. Scientists might know how to create viruses, but there are limitations around how well they can do this. If a virus is made by somebody, there will be evidence of human activity all over the virus, and the person will be discovered. Coronavirus does not have human signatures.

2.  Viruses are not quite like bacteria

Bacteria and fungi are living things; viruses are non-living things. Viruses replicate – you start with one virus and they multiply. Some viruses are so dangerous that they can wipe humanity out. Many viruses can harm us. Viruses need a host to survive because they have no organelles inside them that support metabolism.  Bacteria are different –  they are alive. They are “self-contained.” They can do a lot of things themselves, like carry out their own metabolism - make their own energy - and move around. Some of the bacteria at the bottom of the realm do also need living cells for them to function, but viruses will always need other organisms to survive.

3.  Viruses do not survive long outside a host

Viruses are a package of genetic material and proteins but they lack important components - organelles - that keep organisms alive. To be effective, viruses need to multiply and consume energy, and therefore they take advantage of host cells. That means if they are in the environment after some time without a host, they will just get destroyed. For instance, if you leave SARS coronavirus out in the air, it will get destroyed, but bacteria can survive and thrive in a wet place.

 4. Some viruses will cross over from animals to humans

Some viruses affect animals, others affect plants, while some affect humans. Some viruses will even affect and kill bacteria. In fact, those ones are called bacteriophages.

Some viruses will only affect animals. Some affect only plants and will not cross the barrier to other living things. In animals, some viruses are species-specific, so they will affect only a certain kind of animal. The ones that bother humans are the ones that can cross over from animals to humans.

Diseases that cross from animals to humans are called zoonoses (singular: zoonosis). Zoonoses can be caused by bacteria, viruses or fungi. Fungi is what causes things like ringworms. You can pick up some bacteria from chicken and eggs; like Salmonella.

There are many viruses you can catch from animals, such as Ebola, SARS Coronavirus 2, Rabies, Monkey pox, Yellow Fever, Rift Valley Fever, the list is long. Of course, you can also get Ebola from another human who has it if they touch you or if you touch something contaminated with the virus, like a doorknob, or when droplets fall on your skin.

5. Viral zoonoses can be transformed in humans

When viruses cross from animals to humans, they may sometimes cause the same kind of illness. For instance rabies. If a rabid dog bites you, the virus you catch is the same as the one in the dog. It will drive you crazy and could kill you. If we look at the rabies virus in the lab, it looks just the same regardless of whether it came from dog or human.

For some other viruses, some changes occur to them for them to be able to cross over to humans. For instance, SARS CoV-2 (Covid-19) crossed over from bats to pangolins, and then probably to another animal before the changes it underwent were sufficient for it to easily infect humans. So if you look at the one in humans, it looks slightly different from the one in bats and more similar to the one in pangolins. Still, it is dissimilar enough from the one in pangolins for us to say that there is probably another animal involved, in-between.

Viruses have signatures, so you can tell SARS CoV-2 infected bats first and then pangolins, and so on. By and by, the science of looking at the genetic makeup of viruses and other organisms, and to tell these stories about them, is well established in our laboratories here in Kenya.

 If you take a swab from an animal, say, a snake’s mouth, you will find so many viruses and bacteria of all types. So a snake can give you terrible viruses and bacteria. So can rats. So can other people. And people often bite others. I think the bottom-line must be that it is a terrible idea to be bitten by anything. Even dogs. Just don’t get bitten.

 6.  Viruses cause some cancers

Many viruses have the potential to make a person sick. For instance, they can give you blood problems, such as the coronavirus. Others will give you mental problems, like rabies. Others will degrade your immune system, so you end up catching another infection, such as HIV. Other viruses will cause cancer. Many cancers of the liver, Burkitt’s Lymphoma (cancer of the jaw), cancer of the cervix, cancers of the ear nose and throat (ENT) like nasopharyngeal cancer, cancer of the blood vessels (Karposi’s Sarcoma) are caused by viruses. That is why we say some cancers are preventable. For example, cancer of the cervix can be prevented by early introduction of the Human Papilloma Virus Vaccine.

7.  Be wary of insects

There are some viruses that are called arthropod-borne viruses, as they are carried by arthropods, which are animals that have jointed legs. This group of animals includes insects. Some mosquitoes can pass on worms, such as filaria worms, which cause elephantiasis. Viruses like Yellow Fever, dengue, chikungunya and West Nile are all carried by mosquitoes. Ticks can also carry some viruses. Avoid being bitten by mosquitoes, or ticks, or flies. Or dogs or bats – don’t just go into caves and touch things in there. And by the way, some other viruses don’t require a bite. Just touching is enough. Even inhaling. Avoid standing under trees that have bat colonies. And there are so many such trees even in Kenya, such as in Laikipia.

8. Why some viruses are hard to treat   

Some viral diseases have cures, but most don’t. For instance, hepatitis B and C have very effective (but horribly expensive) cures. For hepatitis, some of the drugs are curative, meaning they restore you to full health. The problem is that some viruses keep changing (mutating). So even if you take a drug that targets a certain component of the virus or its action, you might find that the target area already changed.

Also, some viruses infect areas in the body that are hard for medicines to reach, such as the brain, testis, of lymph nodes. In fact, HIV hides inside our own genetic material. Another thing, for some viruses, we have only started paying attention to them now, since we didn’t think they were important to us until they found us, like the current coronavirus.

Some other viruses have drugs that are not curative but they suppress the virus quite a bit. For instance, HIV has very potent drugs which don’t cure, but really bring the virus down to undetectable levels, so that you don’t suffer.

9. Why decades later, HIV still has no vaccine.

It is very difficult to make a vaccine that is effective against HIV. I began my research career in this field. A vaccine for HIV would need to stimulate antibodies that can neutralise the virus and also cells that can specifically attack infected cells. Now, there are a very few places in HIV that render themselves susceptible to neutralisation. Those places are concealed from an antibody attack until just about the time HIV is fusing with a cell.

Let me explain. To have a vaccine that is effective, it has to induce immunity that neutralises the pathogen (the disease-causing organism). There are two kinds of immunity; the humoral/antibody-mediated immunity and the cell-mediated immunity. I will focus on the first kind in this case. For the humoral immunity, the antibodies (proteins produced by immune system to fight infection) must attach themselves to a place on the pathogen that would paralyse it. This means it renders the pathogen unable to move, unable to function and unable to infect. In addition, the mixture of the pathogen and the antibodies can then be “eaten” by the cells. Think of it like adding sugar (antibody) onto a bitter substance (virus) to make it sweet enough to eat. That is called phagocytosis.

The antibodies must attach themselves to parts of the pathogen that enable neutralisation, and that also facilitates phagocytosis (being eaten by cells). The virus can be eaten by cells once it is coated with antibodies.

Now, HIV infects by entering the cell. And the part that binds to the cells is called gp120. If you could make an antibody that attacks that protein, the gp120, HIV would not be able to bind to the cells in your body. And your cells wouldn’t be infected. Unfortunately, that part that binds to the cells, the gp120, is usually hidden before the antibody can bind. If an antibody comes around and searches for a place to bind on the virus, it will not find it. The virus only exposes that part when it is about to bind to the cell, and the antibody will likely not be nearby at that time. That is why it is so hard to make a vaccine for HIV.

10. Changes in viruses makes them hard to beat

Many viruses change all the time, and that is also why they develop resistance to drugs. Some of those changes that viruses undergo are random.

Another challenge is that some viruses are not so relevant to the people who have the resources to make vaccines. For instance, something like Ebola is not present in Europe and America, so why would they spend their money on a vaccine? It only affects them when they travel – they might be interested if they know that.

The challenge in creating vaccines is therefore generally a mixture of the availability of resources and how complicated the science of making a vaccine that induces neutralising immunity is.

11. Why you are advised to let flus run their course

It’s because there is no treatment, so there’s really nothing you can do, and while it will make you feel lousy, it most likely won’t kill you. Influenza keeps changing every year, so it is difficult to make a vaccine that is effective year to year. We have to keep guessing what the next flu might be, then we make a vaccine for it. Sometimes it works, sometimes it doesn’t.

12.  The reason women are more vulnerable to HIV than men

The surface in a woman that can get infected with HIV is larger than that of men. Semen can also carry a lot of HIV. Women are prone to unsafe sex as they are sometimes unable to negotiate for safe sex due to the economic disparity between men and women. Sexually transmitted infections make it easier for the body to get infected with HIV, for instance when they cause sores. And the dynamics of STIs in women are different.

13.  Why some people don’t get infected by HIV so easily

HIV requires more than just the CD4 receptor to enter the cell easily. If you have CCR5 receptor that is in good shape, then it is very easy to get infected. Some people have a mutation that disables the CCR5 receptor on the surface of white blood cells, so they do not get infected easily. Such mutations are common among the Scandinavians.

14.  Why the cervical cancer vaccine only for people aged 26 and below…

We give the HPV vaccine to younger people. This is because as an adult you have already most likely been exposed to HPV though sex. Getting the vaccine after exposure would be like locking the stable after the horse has bolted; an exercise in futility. In some cases though, the vaccine will still be useful even for older people.



It is indeed real

SARS CoV-2 is real. It originated from a specific colony of bats that live in caves in Hubei Province in China. It seems to have affected pangolins before humans. Some other animal may have eaten the pangolin or its contaminated droppings. Humans may have then eaten that creature. Or even touched it. It is thought humans caught SARS CoV-2 mid-last year but real trouble became evident around November.

Why coronavirus is asymptomatic in some people and not in others

This is not well understood. However, for you to have symptoms, it means bad things are happening in your body at a rate you are unable to contain. For instance, you start getting blood clots. That is why some small organs are getting damaged, and it is the reason why when you are admitted to hospital you get blood-thinners. The body can also experience a cytokine storm. This is where the body’s immune system overreacts and injures the cells, which can be fatal. For other people, bad things happen to them because they already have preexisting conditions. These are conditions like diabetes, hypertension, obesity or faulty genetics.

Other people have many things going for them – their genetics are okay, their immune systems are very strong and/or they are young and healthy so they are not suffering so much.

How to differentiate a normal flu from the coronavirus

Previously, we thought that the signs and symptoms of Covid-19 were markedly different from normal flu. But as we learn more, it is becoming harder to differentiate Covid-19 from normal flu. At this time, it is probably reasonable to expect that a person with respiratory symptoms will get tested for SARS CoV-2.

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