The latest outbreak of Lassa fever, an acute febrile illness, in the country has become a major source of worry to many Nigerians.

Since December 2016, Nigeria has witnessed unprecedented outbreak of the disease. Just recently, Lagos University Teaching Hospital, LUTH, confirmed two patients dead as a result of the disease. No fewer than 18 states across the federation have also at least one confirmed case of Lassa fever out of a total of 241 recorded cases with 82 deaths according to statistics from the Nigeria Centre for Disease Control, NCDC. Besides Lagos, affected states include Ogun, Bauchi, Plateau, Ebonyi, Ondo, Edo, Taraba, Nasarawa and Rivers. Others are Kaduna, Gombe, Cross-River, Borno, Kano, Kogi, Enugu and Anambra.The NCDC update showed that between August 5 and 11, 2017, the outbreak was active in Ondo, Edo, Plateau, Bauchi, Lagos and Ogun.

Meanwhile, medical experts are worried that not only is Lassa fever spreading among humans but also among rats. Every rat is now a potential carrier. Sunday Vanguard spoke to Dr. Salu Olumuyiwa of the Virology Unit, Central Resource Laboratory, College of Medicine, University of Lagos, CMUL.

What is Lassa fever?

First, fever is just an elevation of the temperature which is synonymous to so many infections. Lassa fever is basically different because it is regarded as a Viral Hemorrhagic Fever, VHF, that was discovered in the Nigerian town of Lassa in 1969 when two missionary nurses died.   Apart from Lassa fever, we have other VHF such as Dengue, Ebola, Marburg and Yellow fever.   These diseases are spread by contact with infected animals, people or insects. Lassa virus is endemic in Nigeria, that is, it is inherent in the country and transmitted by rodents called the Mastomys specie and there could be human to human transmission of the viral ailment.

How serious is Lassa fever?

Lassa fever is different from Ebola. For instance, Lassa fever is less likely than Ebola to spread from person to person and it is less deadly than Ebola.   For Ebola, the death rate is approximately 70 percent and Lassa is between 10 percent and 20 percent. It is serious if it is not detected early but once detected early the chances of survival increases when the drug Ribavirin is instituted.

Once there is a sustained fever and the person has been treated for malaria and others and the fever persists, that is an indication. It can also be measured when there is also travel history to parts of the country where Lassa fever is endemic.

Why is the infection now spreading to states with no history of Lassa, for example Lagos? 

That is an issue of the changing pattern of the disease, particularly what has been recorded from 2016 till date. There has been a spread across states in Nigeria. There have been more states involved, more cases and those could be associated with so many factors. It could be human factors. It could be the virus itself and it could be the rodents. These are scientific questions that require answers.

How do we answer these scientific questions? 

Nigeria is already answering part of the questions. Right now, there are series of meetings to review the incidence of Lassa, particularly in this last epidemic. We are looking at the changing pattern of the virus and the disease.   A committee is looking at ways to discover other factors that might be related to the cases.   For instance, usually, we see Lassa towards the end of rainy season and the beginning of dry season, that is, from October to March. But in this particular scenario we have at hand, there have been reported cases even during the rainy season.   And this poses many questions that need to be answered. Is it that the virus is changing from what it used to be?   Are there other rodents that are harbouring the virus in our environment and are there other environmental factors?

There have been flooding in some parts of the country.   In Lagos, there was flooding few months ago, that could also be responsible.   But that has no scientific basis until we are able to capture more rats and look at what they carry and then look at the virus to see if it is different from what we have or if there are new strains of the virus.

Talking about rats, there are rats almost in every home, what kind of rats could cause Lassa fever? There is a particular type that is mostly implicated. They are called multimammate rats, that is, rats with many breasts. The scientific name for this rat is Mastomys.   It has also been reported in 2016 that other rats other than Mastomys are also harbouring Lassa fever virus.

There is need for people to have clean their environment and protect their food materials.   There is need to store foods in lidded containers. There should be no leftover foods. This is mostly because the mode of transmission is from contaminants from rodent. It could be from the urine, faeces and sometimes by consumption but that is not the major means. The major means is consumption of contaminated food or water with the urine or faeces of the Mastomys rodent. After humans get the contamination, the greatest risk is now from human to human transmission.

What is just there is that the rats are available in almost all parts of West Africa and they can carry this virus in their urine and droppings and they live in homes and around where foods are stored, so once we keep our foods away from the rats its will also reduce the burden.

After a patient must have survived Lassa, are there side effects of the disease in the survivor?

What is common in Lassa infection is deafness which is a common occurrence, and I don’t think it has been evaluated in Nigeria to determine how many survivors of Lassa infection suffer that complication, so that is a thing we need to look at.

Has any study been done to that effect in Nigeria?

No study has been done on this but there is a possibility of deafness and little or minor side effects for those placed on Ribavirin, an antiviral drug that has been shown to be most effective when given early in the course of the illness, but that will be taken care of at the clinical level which is beyond the scope of the laboratory.

As an expert in this field, do you say government is fully on track?

There is a national Lassa fever steering committee, so government is working hand-in-hand with the Nigerian Centre of Disease Control (NCDC) and we are charting a course for Nigeria to begin to reduce the incidence and burden for Lassa fever in Nigeria.

The committee has been effective for a long period. It is just for the committee to expand its scope and tentacles so that we will have real time information on Lassa fever. If you do not have comprehensive reports of what this thing is, how do you tackle it? So we need to know the actual burden of this disease in the country and there are so many ways that have been put in place to mitigate the virus.

When you say we need to know the burden, what do we do?

It’s to have real-time information on the disease and that is being done excellently now by the surveillance team that is put in place by the Nigerian Centre for Disease Control (NCDC). They are saying, ‘let’s have the true picture’, if not, what we are hearing today wouldn’t be heard. There have been so many deaths over the years in different states that nothing has been associated with. We had problems reporting cases of Lassa but now there is improvement in the reporting. Once we have that, it’s easier for us to put structures and plans in place. What is critical in Nigerian is to break the chain of transmission of the virus. If there are no agents of transmission, then the problems will begin to reduce. It’s to break the chain of transmission and we also need research to develop better diagnosis tools, to know the kind of virus we are dealing with and we need to look at vaccine development because there are no vaccines available yet for the prevention and control of Lassa fever. Now that there is no vaccine, there must be research and development, for us to develop vaccine for Lassa because it is a black’s man problem.

Just recently, LUTH recorded two deaths and some of the doctors were also affected. Does it mean the hospital was not observing high index of suspicion?

LUTH keeps to international standards. Why the case in LUTH was a bit an issue was because it is not a case at inception. If not for the high index suspicion of some of the doctors involved, what we will be talking about would be a different case entirely. And that is why they were said that even after the patients were dead, they should collect samples from the bodies for further investigations.

The LUTH laboratory is well equipped for the diagnosis of Lassa fever. We have been at the forefront of the VHF diagnosis since early 90s and there has been tremendous improvement in the diagnosis of this agent. That is how the lab was able to diagnose Ebola when it came to Nigeria. The capacity in LUTH is of world standard when it comes to the diagnosis of infectious viral diseases. We have PCR both conventional and real time and others available to complement our diagnosis capacity.

In medical practise, whether it is Lassa or not, it is supposed to be done using universal precautions. It has to be standard clinical practice, standard laboratory practice, your Personal Protection Equipment, PPE, must be worn. You do not expect a clinician to examine his patient with bare hands. There are infectious control practices that are available and it is advisable that everyone in the health sector should practice the standard procedure.

What part did the lab play in the containment of the outbreak here?

We are part of the success story because if cases are not confirmed, how do you do follow-up?   So it is part of the key factors. Laboratory is crucial because diagnosis enables isolation, it also enables contact listing and contact tracing. So if that diagnosis is missing, there will be so many people in the society who will be carrying the virus but will not know. So if diagnosis is not there, it’s going to be difficult. But we need to reduce the rats and foods around our household, clean our environment and we should not encroach into the environment of those rodents also because we also practise bush burning etc. Where will the rats go to? They will always go to where there is food?

Talking about diagnosis, don’t you think it is time we have other standard laboratories that we can test some of these diseases?

Yes, the plan of the disease control administration is to have laboratories available for primary testing for Lassa and other VHFs in the six geo-political zones of the country. Those laboratories which have been in existence could serve as reference laboratories, so that we do not over work them

Lastly, you were part of the team that contained Ebola and Lassa among other outbreaks. How were you able to cope, given the sensitive nature of the diseases?

The facilities are here. We have a P2 Plus machine and we operate under strict World Health Organisation and NCDC guidelines. So usually, as a laboratorian, you have to protect yourself, the environment and the sample you are working with. So we have been trained to handle such agents but what is critical is that it has to be done under stringent laboratory protocols and that must be adhered to from head-to-toe

Source: Vanguard

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