GOING by the records of the Federal Ministry of Health, scores of people have been affected in the latest outbreak of the killer-disease, Lassa fever. The high figure has confirmed a verdict by the World Health Organisation (WHO) that people in the sub-Saharan West African region are susceptible to frequent Lassa infection.
According to the WHO report, between 300,000 to 500,000 cases of the virus are recorded annually. Of this figure, 5,000 cases of deaths are recorded yearly. The outbreaks of the disease have been recorded in Nigeria, Liberia, Sierra Leone, Guinea and the Central African Republic.
Almost half a century after the discovery of Lassa fever in Nigeria, the virus has been a recurrent challenge. The first case of the hemorrhagic fever, caused by the Lassa virus, was noticed in 1969 in Lassa, Borno State.
Forty-seven years after, the Federal Government is still grappling with its containment. Lassa fever belongs to the Arenaviridae virus family. Clinical cases of Lassa fever had been known for about 50 years.
It is one the two recurring diseases which successive governments had contended with until Ebola came into focus two years ago.
Routinely, the government has the outbreak of meningitis and Lassa fever to tackle and, unfortunately, all past reponses were curative. No government took a preventive measure to stop the yearly plagues.
The three deadly scourges have animals as their primary hosts. Ebola has bat and monkey as its primary reservoir; meningitis has chicken as its host and Lassa virus’ primary host is the natal multi-mammate mouse (Mastomys natalensis), an animal found in most of sub-Saharan Africa.
It is popularly called bush rat (Mastomys) in Nigeria. The virus is probably transmitted by contact with the faeces, saliva or urine of animals accessing grain stores in residences. Given its high rate of incidence, Lassa fever is a major problem in affected countries.
Though there is no vaccine that insulates a person against Lassa fever infection, but the treatment and vaccines are available. The antiviral drug, ribavirin, seems to be an effective treatment for Lassa fever if given early on in the course of clinical illness. There is no evidence to support the role of ribavirin as post-exposure prophylactic treatment for Lassa fever.
But, how will the Federal Government put the latest outbreak behind it? The Minister of Health, Prof Isaac Adewole, described the development, which came less than two years after the country battled the deadly Ebola scourge.
According to Prof Adewole, the outbreak has been noticed in 10 states within the last six weeks. He listed the affected states as: Bauchi, Nassarawa, Niger, Taraba, Kano, Rivers, Edo, Plateau, Gombe and Oyo.
So far, 86 cases of infection and 43 deaths have so far been reported. The mortality rate is 43.2 per cent.
“Our laboratories have confirmed 17 cases, indicative of a new round-trip of Lassa fever outbreak. The first case of the current outbreak was reported from Bauchi in November, last year. This was followed by cases reported by Kano State and subsequently, the other states mentioned above,” Prof Adewole said.
Transmission
It is known that Humans usually become infected with Lassa virus from exposure to urine or faeces of infected Mastomys rats. The virus may be spread among humans through direct contact with the blood, urine, faeces, or other bodily secretions of an infected person. There is no epidemiological evidence supporting airborne spread of the virus. Person-to-person transmission occurs in both community and health-care settings, where the virus may be spread by contaminated medical equipment, such as used needles. Sexual transmission of Lassa virus has also been reported.
Lassa fever occurs in all age groups and both sexes and the highly susceptible are persons living in rural areas where Mastomys are usually found, especially in communities with poor sanitation or crowded living conditions. Health workers are at risk if caring for Lassa fever patients in the absence of proper barrier nursing and infection control practices.
According to a don at the College of Medicine, University of Lagos, Prof Bayo Onajole, poor environmental hygiene, crowded living conditions, poor preparation and preservation of food stuff, such as sun-drying of cassava along the highway and poor storage facility, at home or farms are the main reasons for Lassa fever transmission.
In a chat with The Nation, Prof. Onajole urged Nigerians to take precautionary measures not exposing edibles to rats – the vectors of the virus.
“People should put their garri and yam flour and other food items in plastic bags to prevent them from being exposed to the virus-carrying rats,” he said.
He noted that Nigerians should not be contending with Lassa fever in the 21st Century but for poor funding to facilitate research into perennial outbreaks as well as ignorance on the governed.
Symptoms of Lassa fever
The incubation period of Lassa fever ranges between six to 21 days. The onset of the disease, especially when it is symptomatic, is usually gradual, starting with fever, general weakness and malaise.
After a few days, headache, sore throat, muscle pain, chest pain, nausea, vomiting, diarrhoea, cough and abdominal pain may follow.
In severe cases, facial swelling, fluid in the lung cavity, bleeding from the mouth, nose, vagina or gastrointestinal tract and low blood pressure may develop. Protein may be noted in the urine. Shock, seizures, tremor, disorientation, and coma may be seen in the later stages.
Deafness occurs in 25 per cent of patients, who survive the disease. In half of these cases, hearing returns partially after one to three months. Transient hair loss and gait disturbance may occur during recovery.
“Death usually occurs within 14 days of onset in fatal cases. The disease is especially severe late in pregnancy, with maternal death and/or fetal loss occurring in more than 80 per cent of cases during the third trimester,” the professor stated.
Diagnosis
Because the symptoms of Lassa fever are so varied and non-specific, clinical diagnosis is often difficult, especially early in the course of the disease. Lassa fever is difficult to distinguish from other viral hemorrhagic fevers such as Ebola virus and many other diseases that cause fever, including malaria, shigellosis, typhoid fever and yellow fever.
Definitive diagnosis requires testing in specialised laboratories. Laboratory specimens may be hazardous and must be handled with extreme care. Lassa virus infections can only be diagnosed definitively in the laboratory using the following tests: Antibody enzyme-linked immunosorbent assay (ELISA), antigen detection tests, reverse transcriptase polymerase chain reaction (RT-PCR) assay or virus isolation by cell culture.
The don said the disease has always been with us, adding that activities of rats or rodents should be stopped in homes.
But, the President of the Nigerian Academy of Science (NAS), Prof Oyewale Tomori, believes history will not repeat itself in years to come. He is worried that Nigeria has not taken surveillance system serious in its efforts to curb Lassa fever in time past.
He said: “This is because the resurgence of Lassa fever in Nigeria is a revelation of the nation’s weak surveillance system, poor funding of epidemiology studies, inadequate diagnostic centres and poor awareness of the disease.”
Prof Tomori, a one-time Regional Virologist for the WHO, Africa Region, said: “The current Lassa fever outbreak confirms that we are unable to sustain or repeat our Ebola success because success with one disease can only be repeated if your disease surveillance is resilient, sustainable and consistent.
“Ebola was a new and imported ‘Hollywood’ disease, and it attracted attention and funding. We were all scared to death, especially our political leaders, who still wanted to live to continue to loot us to death. Ebola was also an emergency through which we ‘allocated’ almost N2 billion naira and of course the billions went with Ebola!
“Lassa fever, on the other hand, is our regular and endemic disease so to say – our own ‘Nollywood’ disease. We know enough about Lassa fever, a disease that has been with us since 1969, but we are unable to do anything positive about it, because we do not have a disease surveillance system that is reliable, sensitive and consistent to detect outbreaks on time and a health system that is capable of responding quickly and adequately.”
He said the particular epidemic, which has been reported in about 10 states, though it began last year, still we can only report its spread from state to state, and not progress with its control.
“We are paying for years of neglect of our national disease surveillance and laboratory support systems. We are proving again that we cannot sustain our success with Ebola. This is a shame, but as a nation it looks like we know not what shame is,” he stated.
At a news conference on the virus, the minister failed to state what pragmatic measure taken to end the recurring disease. He hinted of the palliative responses, only aimed at managing the situation.
The minister did not reel out methods that wouldbe adopted to strengthen the nation’s disease surveillance system against future outbreak of the virus couriered by rats.
In Lagos, the state Ministry of health also appealed to residents in its domains to report any suspected case of Lassa fever in their neighbourhoods to its directorate of disease control on 08037170614, 08023169485.
The ministry in a statement urged residents to avoid contact between rats and human beings, observe good personal hygiene, including regular hand-washing with soap and running water.
It also admonished residents on proper waste disposal and maintenance of clean environment so ward off rats and the storage of food item in rat-proof containers and thorough cooking all foods before consumption.
The government also urged Lagosians to discourage rodents from entering their homes by blocking possible entry points.
It advised food manufacturers and handlers to avoid spreading edibles where rats could have access to them, advising members of the public to report any case of the above symptoms or persistent high fever, which resists the treatment for malaria and typhoid fever to the nearest health centre.
According to the statement, all fluids from an infected person are extremely dangerous, even as it put health workers on the red alert.
The healthcare providers, it said should wear personal protective equipment, observe universal basic precautions, nurse suspected cases in isolation and report same to the local government area or the parent ministry without delay.
According to the statement, early symptoms of the disease, which occur within three weeks of contacting the virus, include fever, headache, chills, diarrhoea, nausea, vomiting, sore throat, backache, and joint pains.
Late symptoms include; bleeding from the eyes, ears and nose; bleeding from the mouth and rectum, eye swelling, swelling of the genitals and rashes all over the body – which often contain blood.
In Benue, the state government has banned the consumption of bush rat to curtail the spread of the virus in its domain.
Governor Samuel Ortom directed people in the state to desist from eating rats for the meantime in the Middle Belt state
Ortom, who gave the directive after a meeting with Vice President Yemi Osinbajo at the Presidential Villa in Abuja, explained the step became necessary following the discovery of case of the virus in the state.
Rat is believed to be a delicacy popular among the people of the state.
“Benue is affected; we have one case of Lassa fever right now that is under control. We have advised our people that rat which is a major carrier, is a delicacy; I am finding it difficult but I have told them to suspend eating rats now until further notice,” Ortom said.
