No one knows why disease is on the rise in Nigeria

The disease has even claimed many lives, just two months into the new year - patients, doctors and other health workers have been victims.

This has given rise to the question of why the disease is proving too stubborn for Nigeria to conquer, as it did Ebola and guinea-worm disease, in which no new cases have been recorded since 2013.

On Wednesday, February 21, 2018, the Director of Disease Control, Edo State, Dr Osamuwonyi Irowa, confirmed that 521 suspected cases of Lassa fever have been recorded in the state so far this month alone.

And as of February 18, the Nigeria Centre for Disease Control(NCDC) reported 913 cases of Lassa fever and 73 deaths. That's compared with 733 cases and 71 deaths in all of 2017.

The number is a valid reason for Nigerian authorities to be concerned and put their best foot forward to end the epidemic once and for all.

"Everyone is scared," says Oyewale Tomori, a retired professor of virology who chairs Nigeria's Lassa Fever Eradication Committee.

Lassa fever, which was originally discovered in 1969 in Lassa village, Borno State, Nigeria, is a severe and often fatal hemorrhagic illness caused by Lassa virus.

Its symptoms start out with a fever, plus a general weakness in the body, then sore throat, muscle and chest pain, vomiting, diarrhea, coughing and stomach pain.

There have been countless outbreaks of various magnitude and severity across West Africa since the discovery.

Annual incidences of Lassa infections across the region was estimated at 300,000 and deaths at 5,000.

However, many cases were said to be unaccounted for due to scarce resources to diagnose the illness as well as inadequate surveillance.

Why the spread?

In combating the latest menace in Nigeria, the World Health Organization(WHO) has offered support to the NCDC.

The NCDC is following up with 1,747 people who encountered Lassa fever patients in order to diagnose cases early and prevent more infections.

In a recent statement, the WHO representative to Nigeria, Dr. Wondimagegnehu Alemu, expressed concern over the mounting numbers of Lassa fever cases and deaths.

"The high number of Lassa fever cases is concerning. We are observing an unusually high number of cases for this time of year," Alemu said.

WHO's spokesperson Tarik Jasarevic also said that the organization has sent 20 people to Nigeria to support NCDC and shipped 40 boxes of face masks and goggles to hospitals to protect anyone in close contact with patients.

According to reports, 10 to 15 percent of Lassa fever patients who are hospitalised die from the virus.

Being a virus that jumps from the Natal multimammate rat (also known as African rats) to humans, it is believed that the seasonal outbreaks are as a result of West Africa's dry season.

The weather pushes rodents closer to people to scavenge for food.

Hence, virus-carrying rats may defecate or urinate in grains and other food; people can pick up the virus from contact with contaminated products.

The rats that spread Lassa fever are said to be native to many regions of West Africa.

A global health researcher at Tulane University in the United States, Lina Moses said because there is a lot of rats in Africa, there's a lot of potential for outbreaks "if you compare this to the Ebola epidemic from 2014-2016, that likely came from one animal to spill over into the human population."

"So in terms of control [Lassa fever] is much more challenging," Moses said.

According to Moses, there is a better diagnostics of Lassa Fever in West Africa now because of the Ebola epidemic, which led to improved labs and diagnostic testing across the region.

Doctors use the same blood tests to identify Ebola as they do for Lassa fever, she said.

The researcher added that better diagnostics do not entirely explain the 2018 caseload of Lassa fever.

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In a paper Moses published in 2016, she looked at the way the rat that carries Lassa fever interacts with humans.

Examining data on climate change, population growth and land use, she suggests that the annual number of Lassa fever cases could potentially double by 2070.

She said is crucial to investigate the causes of the current outbreak so that future outbreaks would be handled better.

Nigerian public health officials are, however, concerned that people will lose the zeal to fight Lassa fever when the raining season comes.