Scientists establish link between Lassa fever,
AS the Lassa fever epidemic continues to spread in Nigeria and the report of World Health Organisation (WHO)-confirmed case of the Ebola Virus Disease in Sierra Leone on Friday, there are fresh concerns of possible new outbreak of the virus in West Africa.
In fact, the WHO, in a statement, on Friday, said there is ongoing risk of new flare-ups of the virus in affected countries even as the latest death from Lassa fever in Rivers State and new confirmed case in Lagos bring the total number of deaths to over 43 with over 90 cases in 12 states of the federation.
WHO stressed in a statement on Thursday, that Guinea, Liberia and Sierra Leone remain at high risk of additional small outbreaks of Ebola in the coming months due to the virus persisting in survivors after recovery.
The Guardian’s investigation had revealed that the fresh outbreaks of another haemorrhagic fever (Lassa fever) might be a prelude to possibly another outbreak of Ebola.
The Guardian’s investigation revealed that Nigeria and indeed West Africa are presently in the peak season for Lassa fever. It was reliably gathered that the viral haemorrhagic fever has been largely forgotten in the Ebola crisis, and health workers are warning that they may not have the resources to deal with the disease if cases increase.
It was also gathered that at first sight the symptoms of Lassa are identical to Ebola; there can be bleeding, vomiting and fever. But whereas Ebola is a new outbreak, Lassa is a constant presence. According to the WHO, every year it infects from 300,000 to 500,000 people, killing up to 20,000.
The Guardian learnt that all of the countries worst hit by Ebola are home to Lassa fever and that there is one main difference between an outbreak of Ebola and Lassa. Rats cause a Lassa outbreak. The rodents carry the disease into homes and food stores, especially in the dry season running from November to April.
Once infected, Lassa can spread from person-to-person. Not everyone who catches it becomes seriously ill, but fatality rates have been known to be as high as 70 per cent. It is less easily transmitted than Ebola, but nonetheless patients must still be treated in complete isolation.
The remaining health workers in West Africa are already overstretched with Ebola. As cases of a second haemorrhagic fever begin to rise, some are worried that Lassa may go undiagnosed and untreated.
Prof. Christian Happi of Redeemer’s University, Ogun State, told journalists: “Attention has completely shifted now from Lassa to Ebola. There are cases of Lassa fever being actually considered to be Ebola cases in many places. In that regard it is a very complicated situation for us, especially in Liberia and in Sierra Leone.”
It has been shown that Lassa fever is less fatal than Ebola and can be treated with a drug. Ribavirin is used to help patients recover but it is useless for Ebola and is only given once Lassa has been confirmed. Rapid tests are not widely available and without them only a laboratory can tell the difference between an Ebola patient and a Lassa patient. Delays in treatment can be fatal.
The Guardian investigation also found that Ebola, Lassa fever, Dengue fever and Yellow fever are some of the haemorrhagic fevers that have been reported in Nigeria in the last three years; and that an outbreak of Lassa fever in early 2014 in Edo State and some other states heralded the Ebola outbreak in Lagos and Port Harcourt.
Several studies have shown that the spread of Lassa fever in a number of communities in different parts of the country was as a result of poor personal hygiene.
The primary animal host of the Lassa virus is the Natal multimammate mouse (Mastomys natalensis), an animal found in most of sub-Saharan Africa. The virus is probably transmitted by contact with the faeces or urine of animals accessing grain stores in residences.
Also, a new study published Tuesday in PLOS suggests that areas of increased poverty are associated with higher rates of Ebola virus transmission.
It was also gathered that at first sight the symptoms of Lassa are identical to Ebola; there can be bleeding, vomiting and fever. But whereas Ebola is a new outbreak, Lassa is a constant presence. According to the WHO, every year it infects from 300,000 to 500,000 people, killing up to 20,000. The Guardian learnt that all of the countries worst hit by Ebola are home to Lassa fever and that there is one main difference between an outbreak of Ebola and Lassa. Rats cause a Lassa outbreak. The rodents carry the disease into homes and food stores, especially in the dry season running from November to April.
Ebola and Lassa fever belong to the same family. They are called viral haemorrhagic fever. It is a general term for a severe illness, sometimes associated with bleeding, that may be caused by a number of viruses. The term is usually applied to disease caused by Arenaviridae (Lassa fever, Junin and Machupo), Bunyaviridae (Crimean-Congo haemorrhagic fever, Rift Valley Fever, Hantaan haemorrhagic fevers), Filoviridae (Ebola and Marburg) and Flaviviridae (yellow fever, dengue, Omsk haemorrhagic fever, Kyasanur forest disease).
Lassa fever is an acute viral haemorrhagic illness caused by Lassa virus, a member of the arenavirus family of viruses. It is transmitted to humans from contacts with food or household items contaminated with rodent excreta. The disease is endemic in the rodent population in parts of West Africa. Person-to-person infections and laboratory transmission can also occur, particularly in the hospital environment in the absence of adequate infection control measures. Diagnosis and prompt treatment are essential.
Lassa fever is an acute viral haemorrhagic illness of one to four weeks duration that occurs in West Africa.
The Lassa virus is transmitted to humans via contact with food or household items contaminated with rodent urine or faeces.
Person-to-person infections and laboratory transmission can also occur, particularly in hospitals lacking adequate infection prevent and control measures.
Lassa fever is known to be endemic in Benin (where it was diagnosed for the first time in November 2014), Guinea, Liberia, Sierra Leone and parts of Nigeria, but probably exists in other West African countries as well.
The overall case-fatality rate is one per cent. Observed case-fatality rate among patients hospitalized with severe cases of Lassa fever is 15 per cent.
Early supportive care with rehydration and symptomatic treatment improves survival.
WHO’s Special Representative for the Ebola Response, Dr. Bruce Aylward, said: “We are now at a critical period in the Ebola epidemic as we move from managing cases and patients to managing the residual risk of new infections.
“We still anticipate more flare-ups and must be prepared for them.”
Sierra Leone is still in a 90-day period of enhanced surveillance following the declaration on November 7, 2015 of the end of Ebola transmission in the country. This period is designed to ensure no hidden chains of transmission have been missed and to detect any new flare-ups of the disease.
The Sierra Leone government acted rapidly to respond to this new case. Through the country’s new emergency operations centre, a joint team of local authorities, WHO and partners are investigating the origin of the case, identifying contacts and initiating control measures to prevent further transmission.
The WHO had said all known chains of transmission in West Africa have been stopped, as they declared the most recent outbreak of Ebola virus disease in Liberia to be over.
However, there is evidence the Ebola virus can persist in the bodies of survivors after they have recovered from the disease.
This is not the first time Liberia has been declared free of Ebola transmission – the WHO made a similar announcement in May 2015, but the virus returned twice, once in June and then again in November.
What makes this occasion different is that the other two countries most affected by the recent outbreak – Guinea and Sierra Leone – have also been declared free of Ebola. The WHO declared Sierra Leone free of Ebola in early November, and Guinea achieved the same status in late December.
For the first time since the start of the epidemic two years ago, say WHO, all three countries have reported zero cases for at least 42 days.
To be declared free of Ebola, a country must achieve 42 days (two 21-day incubation cycles of the virus) since the last confirmed patient tests negative for the disease two times.
The recent outbreak in West Africa is unprecedented in world history. It has infected over 28,500 people and claimed over 11,300 lives. It has devastated families and communities and significantly weakened the health systems and economies of all three countries.
Risk of additional Ebola outbreaks continues
While praising the monumental efforts of the governments and people of the countries affected, and the organizations that have partnered with WHO in bringing the epidemic to an end, the UN agency warns that “the job is not over” and “strong surveillance and response systems will be critical in the months to come,” as it is likely that flare-ups will occur.
There is a high risk that small outbreaks of Ebola – like the most recent one in Liberia – will occur.
The WHO say 10 of the flare-ups that have occurred were not part of the original outbreak and were likely a result of Ebola persisting in survivors who have recovered.
There is evidence that while the Ebola virus may disappear from the bloodstream of survivors relatively quickly; it can survive in “niches” in the body. For example, it can survive in men’s semen for seven to nine months and in the eye for two months after recovery.
Aylward said the epidemic is in a critical period as countries move from managing infected patients to managing the risk of new infections.
He noted that the risk of new infections is gradually reducing as the virus clears from the survivor population, but “we still anticipate more flare-ups and must be prepared for them.”
Aylward added: “A massive effort is under way to ensure robust prevention, surveillance and response capacity across all three countries by the end of March.”
Looking after survivors is an important part of this phase. As well as screening for persistent virus, they will need medical and psychological care, and support to help them return to normal life in their families and communities, who will also need education and help to reduce stigma and minimize risk of Ebola virus transmission.
One of the factors that appears to have hampered control of the recent Ebola epidemic in West Africa, and made it difficult to apply aggressive quarantine programmes, is the lack of maps or census data. This was the conclusion of a review on the role of mapping in preventing epidemics that Medical News Today reported recently.
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1 Comments
Epidemiology unit of healh ministry forgot to be functionally proactive and was apparently caught napping
We will review and take appropriate action.