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The Protracted Rat Vs Human War: Lassa Fever By Victor Uduaghan

March 1, 2016

The recent Lassa fever outbreak in Nigeria is an opportunity for us to reevaluate our approach to public health. The Nigerian leadership at various levels must begin to make decisions on the best ways to improve the health of its citizens. In my opinion, the current system is not working for us, and we must begin to rethink the structure of our healthcare system.

The recent Lassa fever outbreak in Nigeria is an opportunity for us to reevaluate our approach to public health. The Nigerian leadership at various levels must begin to make decisions on the best ways to improve the health of its citizens. In my opinion, the current system is not working for us, and we must begin to rethink the structure of our healthcare system. The current system is inefficiently government-centric, depriving the more efficient private sector the necessary funds to grow. It is too focused on expensive medical care, instead of the more cost effective preventive health strategies. Nigeria spends billions of naira each year on medical care; with little impact on the health of our people. It is not just because the money is mismanaged, but because it is allocated in the most inefficient way.


The current Lassa fever outbreak is clearly a symptom and an outcome of our ineffective approach to the health of Nigerians.  If we are serious about winning the war against our smaller co-mammals - and their associated diseases - we must individually be responsible for our actions, and demand true leadership from our elected and appointed office holders. We know that the best way to save lives, and improve human health capital is to invest in public health measures like vector control, clean water, proper sewage and waste disposal system. Unfortunately, our healthcare budgets are devoid of meaningful public health votes, and are overburdened with salary and recurrent expenditures on secondary and tertiary health care services. The government must begin to refocus its health care efforts on public health, and on the regulation of the private health sector. It should fund, regulate, monitor and transfer medical care (secondary and tertiary healthcare) to the more effective private sector. And, in our current spirit of merging ministries, maybe we should merge the ministries of environment and water resources to the health. Unless, we can come up with a more practical matrix system amongst these health related ministries, rather than the current silos in which they operate. Otherwise, the rats will continue to win this war.

Ever since man declared war on rodents by encroaching and destroying their natural habitats, rats have responded in not so subtle ways. The hostility has been insidious, and at times ferocious in what we would call outbreaks, epidemics and pandemics. Battalions of these rodents, called commensals, moved into our homes under the guise of searching for food and protection. And have unleashed lethal microbes into our bloodstreams through our most fundamental needs - air, water and food. These small mammals have turned our homes into theirs, and our food into weapons with which to destroy the physiologic processes that keep us alive. Their focus on our most basic needs - physiological and safety - speaks to the advanced mammalian brain in their skulls, and to their tactical capability to wage a complex war.

Rats are ubiquitous, and their population has continued to explode largely because of the nature of their reproductive cycle. With a gestation period of about 3 weeks, their females, can litter up to 8 times in a year, and each litter consists of 4 to 8 offspring. A single female rat can have up to 15,000 descendants in a year. Most of these rats survive to adulthood because man has provided safer harbors for them by decreasing the population of their natural predators - snakes.

Humans have all but guaranteed victory for rats by the way we live. We have not only supported explosion in their population, but have promoted rat-human interactions by simply failing to make our gari, rice and beans inaccessible to rats. Our grains are stored in bags that are easily accessed by rodents, and our garbage is saturated with nutritious leftovers kept in un-sealable containers. House rats are omnivores that would gnaw through any food material in their path, but have a predilection for grains and seeds - granivores. They have a large appetite for food, and are aided by very functional intestinal motility. The presence of these mammals in our homes is given away by their droppings scattered over food storage areas. We have attracted these ubiquitous mammals into our homes by our less than hygienic food habits, and they have come to stay.

Rats, as vectors of diseases, have been known to mankind some thousands of years ago. In some cases, they have been aided by tiny fleas. Today, we know that rats act as vectors for over 60 human diseases, including Rat-bite fever, Leptospirosis, Salmonellosis, Lymphocytic Chorio- meningitis, Plague and Lassa fever, amongst others. Virtually every class of microbe (viruses, bacteria, protozoa, helminths) is transmitted from rats to humans.  Humans get infected directly by rat bites, or indirectly through ingestion of rat excreta. These diseases are known as zoonotic diseases because they are transmitted from animals to humans. While disease like Plague has been with man since the biblical age, it is only in the last century that Plague was linked to rodents. Plague has inflicted humanity for centuries, and has resulted in the deaths of millions of persons.

Unlike the pandemic nature of Plague, Lassa fever is considered a West African disease whose etiological agent was only recently isolated in 1969. Lassa fever is caused by Lassa virus. This virus gets to humans through ingestion of food contaminated with rat excreta, inhalation of virus- laden dust, and through consumption of rats as food. It can also be secondarily transmitted from human to human. The multi-breasted house rat is the natural host for this virus. This multi- mammate rat (Mastomys natalensis) is found in most households in West Africa. They are seen crisscrossing living rooms (embarrassingly) during the Harmattan and early rainy seasons looking for food to eat.

There have been several outbreaks of Lassa fever in the West African region since this disease was recognized, and named after a small town in Borno State, Nigeria. Between 300,000 and 500,000 individuals are affected annually by this deadly ailment that has an overall fatality rate of about 1%. This is an underestimation of the true death rate due to the lack of proper surveillance and inadequate diagnostic equipment. Eighty percent of persons infected with Lassa virus have no symptoms. The incubation period (from the time of infection to the onset of symptoms) for this disease is about 1 to 3 weeks. Unfortunately, the symptoms of Lassa fever are very similar to other endemic diseases like Malaria and Typhoid fever. The symptoms include fever, weakness, body pain, headache, cough, red eyes and vomiting. These small innocent looking, beautifully furred creatures are sleek in their choice of weapon, “Lassa-RNA 3.4/7kb destroyer.” The symptoms of this ailment are very nonspecific, and are disguised to evade the radar of unsuspecting physicians. Although, the majority of individuals inoculated with Lassa-RNA 3.4/7kb by multi-mammate rats are asymptomatic, this weapon is still considered one of the most lethal genome known to mankind. It is classified as Biosafety Level 4 and National Institute of Allergy and Infectious Diseases (NIAID) Biodefense category A agent.  In severe cases, this virus invades every organ, destroys blood vessels and causes fluid leakage in virtually every compartment in the body. It causes fluid accumulation around the lungs, facial swelling, and blood oozing from every part of the body. About 15% of severe cases succumb to the devastating impact of this virus in their body. Death usually occur 10 to 14 days after the onset of symptoms. For those that survive, over 25% will suffer from sensorineural deafness as a result of damaged ear nerves.  According to the Nigerian Centre for Disease Control, as of January 24, 2016, the current outbreak has affected 172 persons, with 57 confirmed cases. Among the confirmed cases, 34 died, resulting in a case fatality rate of 60%; far higher than the expected 15% CFR. Just like in human vs. human wars, this virus has been indiscriminate in the war front. It is a “carpet bomb” that uses the tactic of saturation

bombing, and does not spare children, pregnant women and their unborn fetus. In fact, the fatality rate in pregnant women is over three times more than in non-pregnant population.

So, why have our smaller siblings in the mammalian world so successful in this unending war. Is it because their precision guided weapons are too lethal for our body’s defenses. Or because we are weaklings for failing to fortify our homes and keep our environment clean. Whatever the rational, and however irrational it may sound to us, rats have recorded recurrent successes in this perpetual war.  And it is time for humans to fight back. Complete eradication of this rodent is not practical because they are ubiquitous. Humans have explored several defensive and offensive strategies aimed at curtailing the damage done by this multi-breasted mammals, whose females have prostate glands.

One of the tactics used to control rats is to recruit mercenaries from the feline world - biological control. Cats are natural predators of rats. They have greater inclination and enviable prowess for going after rats, and do a pretty good job at scaring rats from the house. However, rats are able to neutralize this human defense easily. They often evade cats by flattening themselves into small nooks and crannies that are too small for their predators. A maneuver that is possible because of their small, slender size, and malleable soft bones. Cohabitating with cats also come its own health and financial hazards. Cats are vectors for certain dangerous human diseases like Toxoplasmosis, Hookworm and Giardiasis. Additionally, cats prey on domestic livestock. In families that farm livestock like fowls, there is a risk of losing the fowls to the ravaging paws of cats. For these and many other reasons, we cannot rely absolutely on our mercenaries to fight this war for us.

Poison baits, another control tactic used by humans, is targeted at the voracious nature of rats. Coumadin, a bleeding agent is the common rodenticide in the market today, and is embedded in food and placed in paths traversed by rats. Unfortunately, the result of this tactic is the notorious fetid smell emanating from the carcasses of dead rats that permeate every corner of the house for days. This is one reason for recommending “outdoor use only” for poison baits.  Additionally, rat poisons are not only toxic to rats, they can be fatal to humans if ingested accidentally. It is therefore not the ideal panacea to the problem of house rats, especially in homes with children. Strict precaution should be followed when using poison baits to avoid accidental human ingestion.

Another artillery in our arsenal is the spring-based trap. This device smashes the backbone of any rat that is so unlucky to trigger it, but it has a low success rate. Humans often wake up in the mornings to see either un-triggered traps, or triggered traps without the prey. This is because rats are very smart mammals that quickly learn to avoid them. These traps are considered by some people as finger-traps, rather than rat-traps because of the high risk of fingers being caught in between the bars. An additional safety concern with this device is that when successful, rat blood is usually splashed all over the trap, posing a significant risk of exposure to the very Lassa virus we are trying to prevent. For this and other reasons, cage traps made of boxes are preferred. These boxes trap live rats that can then be properly and safely disposed. Funnel-door wire traps are as effective as cage traps, and have the added advantage of been able to trap more than one rat.

Another interesting weapon in our arsenals for fighting rats is the glue trap with bait. Often effective, but can be argued to be as barbaric as water boarding. In my opinion, death from being glued to a board is a cruel way to die. Usually, we end up with a rat that has defecated all over the trap while struggling for live. Just like with the spring-loaded traps, one has to be very careful when discarding a glued rat to avoid exposure to excreta. Proper common sense precaution should be adhered to when disposing dead rats, including the use of hand gloves. Before handling the rat, disinfect the trapped rat and contaminated area by pouring copious amounts of household bleach on the rat and the surrounding area. Use disposable rubber gloves, and carefully dispose the rat. The rat should be placed in a plastic bag, and sealed tight. After disposing the dead rat, the area should not be swept to avoid dispersing virus-laden dust, instead, mop the area thoroughly.

More advanced technique like the electronic rat trap is gaining in popularity. These devices are able to detect rat movements, and then deliver high voltage shock to kill rats. The shock has to be delivered long enough for the rat to remain dead since rats are able to revive their heart spontaneously after simple electric shock.

Despite all these tactics that man has employed to win this war, rats continue to devastate our way of life. “Soaking” our precious Ijebu gari is now a nightmare. The fear of Lassa fever has scared those of us that cannot differentiate the usual dark gari particles from rat poop. Even persons that can pinpoint rat poop, rightly avoid gari for fear of rat urine. Both rat poop and urine are potential sources of Lassa virus.

So, why have we failed so miserably in our efforts to exterminate these small mammals from our homes. There are more than enough blames to go around, from individuals, to families, communities, and to political leaders. Individuals and family units must accept the health hazards to rats cohabiting with them.  A level of self-responsibility by individuals is needed to rid houses of attractants that bring rats to our homes. We must maintain the level of hygiene and cleanliness necessary to keep rats out of our homes. Common sense measures like washing dishes after eating, and disposing leftovers in sealable containers must be practiced. Garbage containers should be kept at a reasonable distance away from the house. The culture of storing unwashed dishes overnight, as is practiced in some of our communities must be discouraged. Food materials, including grains and seeds should be stored in sealable containers.  In addition to measures aimed at proper disposal of attractants, we should avoid direct contact with rat excreta and blood. When sweeping or disposing food materials suspected of being contaminated with rat excreta, care should be taken to avoid dispersing tiny particles which can be inhaled. Dead and trapped rats should be handled with caution to avoid any skin contact. Accidentally soiled skin should be washed with bleach, and rinsed off with copious water. Communities that eat rats should be educated on the health associated hazards of such meals. Rat meals should be removed from our menu.  Additionally, our compounds should be kept clean. Every compound need to have plastic or metal trash containers that have tight fitting lid. Fruits should be harvested from trees before they fall, and fallen fruits should be picked up immediately not to attract rodents. Any rat harborage in the vicinity should be eliminated. Indiscriminate bush burning is common during the Harmattan season, and must be discouraged. It expels rats from the bushes into our homes. Community awareness of the health hazards of rats must be increased. People need to understand that rats are not just in their homes to feed on seeds and grains, they can transmit deadly diseases. And lastly, our public schools need to be involved in this effort by educating our children on simple public health measures, and on the importance of environmental hygiene.

Furthermore, in times of outbreak, symptomatic persons should present early to the hospital for on-time diagnosis to decrease the chance of person to person transmission. Healthcare workers should have a high level of suspicion, and should practice recommended levels of standard, contact and droplet precautions. Healthcare workers must wear whole body protective gowns, masks, gloves and goggles when caring for suspected and confirmed cases of Lassa fever. Infected patients must be isolated for the duration of illness.

Our generals, the political and healthcare leaderships, should come up with a winning strategy in this battle, instead of only reacting to attacks from rat battalions. Mastomys natalensis has been known to us as the vector for Lassa fever since 1972, but yet, our generals have not been able to formulate a comprehensive strategy to preempt outbreaks. We have been caught flatfooted time and time again. The current outbreak has left our health care leadership running helter-skelter for solutions. This begs the question, what did we learn from the previous outbreaks, and more recently from Ebola. Is Lassa fever not an endemic disease? It is an endemic disease in the West African region according to the World Health Organization.  If so, why does our hospitals not have the ability to run diagnostics tests for this disease. Lassa virus lives in 30% of the population of this ubiquitous rat with which we interact every day. This disease lives with us, and it is widely undiagnosed. The number of patients presenting with fever in our hospitals that is classified as “Fever of Unknown Origin” may not be as high if our hospitals are equipped to diagnose this disease. The Enzyme Linked Immunosorbent Assay (ELISA) and antigen testing for this disease is not so complex, nor are the materials needed too expensive for state governments to afford. Nigeria has 5 national laboratories with reverse transcription polymerase chain reaction (RT-PCR) capabilities. While these centers are necessary for research and emergency situations, l do not think they meet the diagnostic needs of patients in our communities. Especially, with an ailment that has a case fatality rate (CFR) as high as 50%. and where early diagnosis and treatment may make a difference between survival and death. Equally disturbing is the fact that we do not have Ribavirin readily available in our “National Security Drug Stockpile.”

This is an opportunity for us to rethink our approach to healthcare. Billions of naira are spent each year on medical care by our governments; with little impact on the health of our people. It is not because the money is mismanaged, but because it is allocated in the most inefficient way. For us to achieve optimum return on health capital, the government, should focus its investment on proven public health measures. The recent Lassa fever outbreak should be seen as another opportunity for our leaders to improve our environment by investing in clean water, sewage and garbage disposal systems. Most of our cities lack proper sewage system. A majority of our urban and rural dwellers rely on boreholes for their water. The content and quality of water from boreholes are rarely tested, and not known. Our roadsides are littered with household garbage and market trash partly because we lack disposal structures in our cities, towns and villages. It is true that the cost of setting up effective sewage and water system is large, especially in the current economic situation. But we must realize that the return on public health investments are extremely high, and justifiable from the economic perspective of health capital. I am not an advocate for loans, but this is one project area that borrowing is appropriate and justifiable. Imagine the health and financial benefits to individuals, families, communities and governments across the country if we have effective water, sewer and garbage disposal systems. However, the funding for these projects does not have to come from loans. We can raise enormous fund by including health in all revenue – “a policy of health in all taxation.” For an example, enormous revenue can be raised by adding environmental surcharge on the cost of all recharge phone cards purchased in the country. Billions of Naira can be raised each year from just imposing a 5% environmental surcharge on phone cards and a 10% health tax on airline tickets; if the money does not leak into private pockets.

The key to a healthy healthcare system in Nigeria, in my opinion, is a strong and vibrant private health sector. The role of government in public health care needs to be reviewed and strengthened. A quick look at the federal government’s budget shows an alarming and disturbing direct role of the government in healthcare. If the budget is a true reflection of government expenditure on health, it is difficult to see our path to achieving a developed health system.  Our current strategy is overwhelmingly government-centric. The federal government is either directly expending the funds in the health budget, or channeling it through the lower two tiers of government at the expense of the potentially more efficient private health sector.  The private health sector must be supported and incented to blossom. After 55 years of independence, we should not allow the bureaucracy and inefficiency in the public sector to continue to drag down our potential to have a true healthcare for all. The government needs to hand over medical care to the private sector so it can focus on regulatory, oversight and high yield public health initiatives

If we are truly serious about winning this war against our smaller co-mammals, we must hold ourselves responsible for our current ordeals, and demand true leadership from our current elected office holders. For now, the war continues and the rats are winning.