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RESEARCH &DEVT: Humidity affects meningitis epidemic – Prof Wali

Stories By Ebele Orakpo

Professor Sadiq Suleiman Wali (OFR) is a consultant physician mainly in hepatology and gastroenterology and has interest in infectious diseases. In this chat with Vanguard Learning in Abuja, the former Kano State Commissioner for Health andChief Physician to five Nigerian ex-Heads of State, speaks on his research work in meningitis control, treatment and prevention. Excerpts:

Said Wali; “I was a lecturer in Ahmadu Bello University up till 1984 where I rose to be a Reader in Medicine and I eventually moved to Kano as Professor of Medicine in Bayero University Teaching Hospital. I picked meningitis because at that time, we were very lucky to have a team from the Medical Research Council of the United Kingdom. They had a base in Zaria and they showed a lot of interest in meningitis and all other basic diseases but I picked meningitis in particular because having a large population with meningitis is a huge burden. It has a huge social and economic impact on such nation. Meningococcal meningitis can be fatal or cause great harm without prompt treatment.

“Cerebral meningitis is a disease that occurs mainly in sub-Saharan Africa in what is called the Meningitis Belt. The Meningitis Belt spreads from the Sahara down to Kaduna area, across Abuja and from Senegal down to Ethiopia and Somalia. This is an area where we have very massive meningitis epidemic every eight to 10 years. These epidemics are caused by the bacterium called Neisseria meningitidis also known as meningococcus. Meningococcal meningitis has several serotypes, like tribes. Meningococcal meningitis A is the major one; about 80 – 90 per cent of meningitis is caused by meningococcal meningitis A so we were interested in finding the prevalence of the different serotypes in the north. We also had interest in the treatment, in particular, we were interested in prevention and epidemiology so we worked on all these aspects of meningococcal meningitis.”

Prof Wali
Prof Wali

 

Epidemiology:
“Like I said, it is mainly meningococcal meningitis A that causes the epidemic but there are others – C and W135 do cause it too. These are the major ones and right now, there are vaccines for the three but back then, it was mainly A. We were interested in that because eventually, we had to go into vaccination. We did a lot of vaccination studies with a vaccine. By then, the meningococcal meningitis type A vaccine had just been introduced. We did the studies, trying to see whether to do mass vaccination ie vaccinate all the people where there is epidemic or we do selective vaccination.

Vaccination:
We chose selective vaccination because it was more cost effective. So we did control studies in different villages around Zaria and see whether the vaccine was effective. In some villages (experimental villages), we gave them the vaccine, and in control villages, we did not give the vaccine. We followed them up to see what happened. We followed their admissions into health centres and hospitals. We were happy to find that it was very effective. In fact, if you go to any village after we vaccinate them, a day or two later, we don’t have any more cases while in the villages that were not vaccinated, the cases started to come up.

So that established the efficacy of the vaccine and also because it was in the early stages, talking about 1978-79. We sold the idea to the World Health Organisation that selective vaccination can be more cost effective because you pay very little. So what we said was that if there is a meningitis epidemic in any area, if we get one or two cases in any community, then we will have our team go there and vaccinate them instead of vaccinating the whole state, then you find the disease will disappear.”

Epidemic and climate:
“We found that the epidemic occurs mainly from November to April/May and certainly, when the rain stops, like in Zaria, the rains start around late April to early May and the epidemic stops completely. This was very interesting so we did a lot of research to find out why it happens; did the bacterium disappear or what? We found that actually, it does not disappear, the infection still continues but it is affected by environmental factors which cause the bacterium to move from the throat into the brain.

We used to think that the bacterium disappears with the rains but the infection continues even during the rainy season. Infection is different from disease, infection is found in the throat. We found high infection but no disease; but during that period, (Nov – April), if you have the infection, the climate is conducive for developing the disease so the virus gets away from the throat and goes into the brain. We thought it was the temperature that caused it but we discovered it wasd actually the humidity. When the rains come, humidity rises, diseases terminate while infection remains.

Drugs:
Treatment with penicillin, the commonest one given in large doses, then Botox, in large volumes four times a day so patients experience severe pains but it works. So we felt we should get a drug that we can give only once a day. We tried two – we got a long-lasting penicillin that when administered, can last for 48 hours or more and there is the long-acting chloramphenicol (Typhomycin). We observed the differences. Typhomycin is given once daily.

From our findings, with the ones we give once a day, the patient is virtually cured within three – four days. It was a very major breakthrough and this has been accepted by the WHO, it is a standard treatment if there is an epidemic. You take this long-acting oily chloramphenicol. That is how we treat and it makes it much easier and much cheaper and then you can use ordinary people; you don’t have to involve doctors and nurses.”


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