People first became aware of the existence of Ebola in July 1976 when it emerged in the southern regions of Sudan. This happened when a gentleman developed some illness and succumbed to it. However, his death was not only excruciating, but also bloody. Following the death of this man, the virus transmitted externally contaminating his mistress, friends and members of his family. And before the outbreak of the virus was over, it had infected a total of 284 persons among whom 150 patients succumbed to the viral infection. This took the mortality rate owing to the virus infection to a little over 50 per cent!
The menace caused by the virus was yet to be over, as Ebola launched another attack in September the same year and this time in neighboring Zaire. In fact, the strains of Ebola that struck people in Zaire appeared to be somewhat different from the strains of the virus that attacked people in Sudan earlier. In Zaire, the virus appeared in a more ferocious form claiming the lives of 90 per cent of the people it infected. During a number of months of rage during the latter part of 1976, the virus invaded people in as many as 50 villages claiming 325 lives of the 358 persons infected by Ebola.
It has been found that the Ebola virus is able to infect as well as multiply itself in practically every type of body tissue, possibly barring bone and the skeletal muscles. When this deadly virus infects an individual, he or she initially experiences an intense headache accompanies by fever and muscle aches. Soon after this, bleeding takes place. Initially, the hemorrhage occurs internally and the factors responsible for blood clotting become active. As a result of blood clotting in the internal organs, the liver and spleen are hardened eventually transforming into dehydrated masses of condensed blood and tissues. The kidneys, which are considered to be the filter plants inside the body, become so congested with thickets of blood that they ultimately stop functioning. All these put together creates an enormous workload on the heart as it tries to pump the condensed mass through the blood vessels to the different parts of the body. And when all the aspects that help in the clotting of blood tire out, it results in unrestrained bleeding. At this stage, the Ebola is said to be going berserk multiplying itself billions of time to devastate the body. As the capillaries worsen, the supply of blood to vital organs, such as the lungs, kidneys, stomach and the intestines, come to a halt. People infected by the virus may also experience inflation of the skin as the blood seeps out of the tissues just beneath it. In fact, the condition of the patients deteriorate to such an extent that blood even oozes out of their eyes. In fact, at this stage the virus Ebola is changing the host or patient's internal organs into a viral broth. The only relief for the patients at this stage of the disease is that they succumb to the infection soon. Either they die due to shock witnessing such heavy loss of blood from the body and extremely low blood pressure or owing to heart failure or blocking of the lungs.
Researches have shown that the Ebola viruses are closely related to Marburg. When examined under an electronic microscope, they appeared almost alike - both seemed to appear filoviruses, denoting they have the shape of threads. Both Marburg and the Ebola viruses possessed analogous genetic substances - a solitary filament of RNA (ribonucleic acid). In addition, like in the case of Marburg, scientists are yet to find the natural host of any of the various Ebola strains.
What is more remarkable regarding the strains of Ebola virus is that these filoviruses are actually not as infective as they were initially seemed to be. While both viruses - Ebola and Marburg, have the aptitude to communicate a disease as well as kill monkeys that breathe in the virus, they cannot be easily transmitted taking help of the air or atmosphere. In fact, these viruses are also highly unlikely to be transmitted by means of casual human to human contact. It has been found that during its outbreak in Sudan and Zaire in 1976, the strains of Ebola did not spread owing to people meeting casually on the streets or visiting the same eateries. In fact, it is paradoxical that the hospitals treating patients infected by Ebola were responsible to a great extent for the small endemics caused by the virus. First, practically there were inadequate supplies of medical requirements. Second, professionals at the hospitals were negligent and irresponsible. For instance, when people came to the hospitals for treatment of malaria or various other diseases, they were injected with the same needles time and again. In fact, either the needles were not sanitized between two injections, as the time between two shots was too small to even wash them.
Like Marburg and Ebola, Lassa fever is also a hemorrhagic fever caused by a deadly viral infection. Thus disease is widespread in the western regions of Africa and is responsible for approximately 5000 deaths in the region every year. Like the Marburg and Ebola viruses, Lassa is also a vicious killer and functions almost in the same manner as the other two viruses. While the virus has been rampaging in the African regions for time unknown, scientists only became aware of Lassa in 1969 when it infected a number of American nurses working in a hospital run by the church in Nigeria. The symptoms of Lassa fever extremely reminds one of the Marburg that was discovered by scientists about two years back in 1967 in the central African nation Sudan. When examined under the electronic microscope, the Lassa virus was found to appear sphere-shaped, very much different from the filoviruses like Marburg and Ebola. In fact, when the Lassa virus, a deadly pathogen, was combined with antibodies for Marburg, there was no reaction whatsoever. In fact, during the investigations, it was found that the Lassa virus was encouraging the body to produce antibodies that were unlike Marburg. Speaking precisely, the Lassa viruses were a completely different type of viruses.
In fact, during the research the scientists observed that the Lassa virus not only had any reaction with the antibodies of Marburg, but they also did not have any interaction with any other known antibody. In other words, all these denoted that the scientists and medical community were now aware of an entirely new 'hot' virus. This led the medical authorities to launch another hunt to find the natural host of this new and deadly 'hot' virus. According to an intuition, the researchers came to a conclusion that Lassa was by no means an arbovirus (arthropod-borne viruses), which are a large group of viruses that are spread mainly by blood-sucking insects. During their investigations, researchers found out that all the infections by this new 'hot' virus took place in the house. They also discovered another fact regarding the spread of the Lassa fever - the virus mainly infected the adults. Generally, insect-borne diseases demonstrate an inclination to infect the children first, as they play in the damp breeding grounds of insects, such as mites, mosquitoes, ticks and others.
The gut feeling of the researchers actually proved to be right. Thus, during their search for the natural host of the Lassa virus, scientists captured over 640 animals, primarily small mammals like rats, mice and bats from the rural areas were people had already been infected by the virus. The scientists collected blood samples of these captured animals and later also removed their hearts, lungs, kidneys and spleens by means of surgery. Finally, all the samples collected were preserved in liquid nitrogen and later shipped abroad for examinations at the Special Pathogens Branch in the United States. When the tests were complete, the results showed that one of the specimens tested proved to be positive. From the tests scientists came to learn that the species Mastomys matalensis or the common brown rat was the natural host of this deadly 'hot' virus.
In fact, viral infectious diseases, such as the Black Death and typhus, were both atrocious exterminators. These diseases were silently initiated among the humans by the brown rats. However, further studies revealed that these maladies were in reality fleas or lice living on and biting the diseased rats, and passed onto the humans. Next, the scientists wanted to find out if this was the actual approach for transmitting the Lassa virus onto the humans or if the rats themselves were responsible for passing on the virus to humans by biting the victims. When those infected by the virus were queried in this regard, they were unable to recall if they were bitten by rodents.
Incidentally, on one occasion when one researcher held an infected rat, the infuriated mammal urinated on him and, regrettably enough, the scientist succumbed to Lassa fever two weeks from this incident. Later, it was discovered that the urine of the infected rat was swarming with Lassa viruses. What was worse is the fact that these infected brown rats were almost present everywhere all over the eight countries in the western parts of Africa and they looked for human dwellings of their choice to reside in. This made life precarious for the people residing in these regions. The infected rats not only urinated on the food, floors and beds, but also on the people while they were asleep. The virus had the capability to enter the human body even through the most minuscule break or pore in the skin. This was really dangerous, as the disease spread rapidly, with no remedy or vaccination in sight.
Before we discuss the topic, it needs to be mentioned here that compared to the common dengue fever, its close relative, the dengue hemorrhagic fever is much harsher in form. Both the diseases are infectious and result in agonizing bone and joint pain and the diseases have acquired their name 'break bone fever' from such symptoms. While the common dengue fever does not lead to hemorrhage, but internal bleeding and ensuing shock caused by dengue hemorrhagic fever results in death in approximately 15 per cent cases.
Dengue is closely related to yellow fever and is an arbovirus like its cousin. This means that the viral disease is transmitted by insect bites or sting of any arthropod. In fact, both forms of dengue are spread by the same agent - a mosquito called A. aegypti. Several researches have shown that mosquitoes are basically most effectual in transmitting diseases. As discussed earlier, the 'hot' virus Ebola spread rapidly in Zaire in 1976 owing to the reuse of hypodermic needles by callous hospital authorities. In this case, a female mosquito (male mosquitoes never bite) is like an airborne hypodermic needle. The long proboscis (nose of an animal) of the mosquito is akin to a needle and is used by the female insect to draw her blood meal from other animals. However, before the female mosquito sticks her long proboscis into the victim's body, she usually performs a peculiar practice. In fact, the female mosquito first prepares the area on the skin to be attacked by spitting on it. The saliva of the mosquito contains an anti-coagulant substance that helps the blood to continue flowing and this saliva may often be full of viral elements. Next, A. aegypti penetrates her long proboscis and ravines herself on a large volume of blood, swelling to the extent of increasing her actual weight four-fold. At this stage the A. aegypti virtually turns out to be something in excess of a hypodermic syringe. In case the blood sucked by the mosquito is infected by dengue virus, the pathogen will start reproducing itself right inside her salivary glands. When this female mosquito spits and bites another target for her blood meal, the dengue virus will be transmitted to the new body causing innumerable miseries to this new victim.