Vanguard (Lagos)

Nigeria: Lassa Fever - And the 'Joker' Was Death (3)

opinion

FOR give my interest in this field. I am the son of a professor of Medical Microbiology so it must be in my genes. So aside from petroleum engineering, project management and information technology where I can mix it with the best, politics and medicine with a tilt towards microbiology also hold a place in my heart.

Now hidden in all the statistics on Lassa fever as well, is the reality of the "swollen belly syndrome"--a Lassa-induced condition in children.

According to the Pathinfo Project of the Virginia Bioinformatics Institute (U.S.A), it causes extreme abdominal distension and bleeding, and has a case fatality rate of about 80per cent! Although Lassa is classed as a haemorrhagic fever, only about 20 per cent of infected adults actually haemorrhage (bleed). Most cases (roughly 80%) are either mild or exhibit no apparent symptoms. Also the agent is more lethal to non-Africans than Africans and seems to prefer the dry season to wet conditions.

No matter the season though, Lassa is a viscous viral predator--a minuscule but murderous pathogen of 110 to 130 nanometres in size (a nanometre is a billionth of a metre). Like other viruses, it dwells furtively, in the realm between living and non-living matter, until contact with a cell occurs.

Then as if kissed by some deathly prince, the micro-monster awakens. It bores through the cell's membrane, seizes its reproductive machinery and proceeds to replicate furiously. This replication, Pathinfo reports, "takes place in the cytoplasm of the infected cell".

The cytoplasm is the cell's industrial layout, its main manufacturing centre. The virus thus hijacks the fundamental infrastructure, processes and materials of life. But it uses these resources to reproduce itself, rather than the host cell.

New viral particles quickly begin to bud on the cell's surface. These "virions", as they are called, are protein spheres wrapped in fat. Each consists of two segmented strands of RNA (the primitive forerunner to DNA)--which identifies it as an arenavirus.

Arenaviruses are linked to viral diseases that cause haemorrhagic fever and are rodent-transmitted. "Each virus," CDC reports, "is usually associated with a particular rodent host species in which it is maintained"..

The main culprit, in the proliferation of Lassa, is Mastomys (Praomys) natalensis--a small, soft-furred and naked tailed rodent, 25 to 27 centimetres long and weighing roughly 60 grammes. It is the most widely distributed rodent in Africa.

Mastomys is also a highly prolific breeder, producing a liter of eight to ten pups monthly, year round. It is known as the "multi-mammate rat" because females have eight to fourteen pairs of tits, instead of the five or six that is typical of other rodents.

Investigators believe the virus is transmitted between rodent by physical interaction, including sexual activity, fighting and even through the air. Pregnant females pass the pathogen to their offspring--perpetuating it for generations, within rodent colonies.

The danger for humans lies in exposure to the urine, droppings (faeces), blood and flesh of infected animals. Human infection can also occur through aerosol transmission--breathing air that is contaminated with microscopic particles of urine or rodent droppings.

Lassa can be spread as well, through person-to-person contact. "This type of transmission occurs," Pathinfo advises, "when a person comes into contact with virus in the blood, tissue, secretions, or excretions of an individual infected with the Lassa virus". This, I should stress, includes sexual activity.

"Person-to-person transmission is common," it continues, "in both village and health care settings, where, along with the above-mentioned modes of transmission, the virus also may be spread in contaminated medical equipment such as reused needles. This is called nosocomial transmission".

It should be carefully noted, that Mastomys natalensis is not the only host rodent. In the wake of the Jos epidemic, scientists from the University of Ibadan and the U.S. Center for Disease Control isolated the Lassa virus in the fluids and tissue of eight wild rodents. Only five were Mastomys natalensis.

In 2006, a team of investigators from Europe, Africa and the U.S.A. took samples from Guinea and corroborated these findings. In addition to natalensis, they found evidence of Lassa infection in M. huberti and M. erythroleucus as well.

So don't be complacent-just because the rodents around you are not small with hairless tails! Eliminate all rat and mice from your surroundings. Clean and disinfect the environment because rats urinate everywhere. Don't leave provisions exposed; and don't consume foodstuff that has been left out.

Also, please refrain from self-diagnosis and self-medication. Report any unusual discomfort, such as unproductive coughing, high fever, chest pain or physical weakness. Unlike Ebola and Marburg, Lassa can be treated with Ribavirin--a synthetic drug that inhibits the production of viral RNA.

Medical workers have found that even expired Ribavirin is useful. But for the treatment to be effective, it must begin during the early stages of the infection because the disease progresses rapidly. It has an incubation period of three to twenty one days and kills in less than two weeks after symptoms appear.

It's doubtful that Lassa fever can be eliminated. The virus is now our permanent companion, a phantom killer lurking unseen in our midst.

We're like players in a deadly epidemiological game. Some animal or human host must always be holding the joker. But nobody ever knows where it is-or when the wild card will hit the table. The story of our nation is not so different. Ravaged by an invisible virus we are unable to live up to our full potential.

Some call it corruption others describe it as ignorance but call it what you will, it is also passed down from generation to generation buoyed on by a lack of education and the absence of an orientation as to its true impact. Again like with Lassa, it is doubtful that it will ever be eliminated but it is my hope that with education and an increased awareness, we too shall eventually overcome.

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