Ebola contagion: the state of art

It was 1976, in the valley of Ebola in the Democratic Republic of Congo (former Zaire), when it was recognized for the first time a virus – belonging to the family Filoviridae – extremely aggressive to humans, causing a lethal hemorrhagic fever with 88% .
Ebola hemorrhagic fever is a range of symptoms such as fever, vomiting, diarrhea, generalized pain or malaise, asthenia and only sometimes external and internal bleeding. Some believe (PE Olson, CS Hames, AS Benenson, EN Genovese – 1996) that the Plague of Athens – which afflicted the city from 429 BC to 427 BC and which Thucydides tells us – was a kind of Ebola haemorrhagic fever.

Some populations of lowland gorillas, chimpanzees and antelope of central Africa are carriers of the virus and have been decimated by Ebola, which is, above all, in three species of bats (Hypsignathus monstrosus, Epomops franqueti, Myonycteris torquata) spread throughout the Afro-Asian equatorial belt that have been voted as natural hosts or viral stocks.
The chain ‘food’ sees the bats leave partially eaten fruits and contaminated by saliva, of which land mammals such as gorillas and antelopes then will eat.

Among humans, the virus is transmitted by direct contact with infected bodily fluids, or, in lesser proportion, by epidermal contact or with the mucous membranes. The incubation period can range from 2 to 21 days, but is generally 5-10 days.

Although viral transmission by air, between monkeys, has been demonstrated in the course of an accidental epidemic occurred in American laboratories located in Virginia, but there is little evidence of human to human transmission routes.

In the early stages Ebola does not seem to be extremely contagious contact with affected individuals as in the early stages does not seem to cause the disease, but as the disease progresses, bodily fluids in the diarrhea, blood in vomit and represent an extreme biohazard.
There is no cure or vaccine, only when the sick are handled promptly we have  a 30-50% of survivals.

So far, due to the lack of appropriate tools and protocols of sanitation, epidemics had broken out in the poorest areas and isolated, but now Ebola has come to the millions people town – as  Conakry, Freetown and Monrovia – and continues to expand despite modern hospitals and trained personnel.

Since March, there have been more than 1.20o Ebola cases and 672 deaths in Guinea, Liberia and Sierra Leone, as well as several others for infected travelers returning to their countries, including a woman from Hong Kong, a Briton and two Nigerians.

But what makes it so dangerous?

“There are no direct flights from West Africa to Hong Kong, but an infected person has arrived in the city by air,” said the Minister of Health of China – “Since Ebola is a highly contagious disease, suspected cases will be put into isolation soon as they are identified. “(South China Morning Post)
Same concerns from the British Foreign Secretary Philip Hammond: in all cases the infected people had been tested for Ebola that was negative.
And ‘this is the reason why the World Health Organization declared’ out of control ‘the epidemic.

The possibility that, taking advantage of promiscuity, and the degradation of the Underworld illegal, Ebola can ‘win’ a city … as in the horror novel The Hot Zone by Richard Preston.

Until now it was thought unlikely that Ebola could be developed with characteristics pandemic worldwide, because of its difficulty to spread by air.
This time, Ebola has been more insidious because less identifiable symptoms: only half of the patients presented cutaneous or internal bleeding but, in the rest of the cases, are prevalent fever and intestinal manifestations and the epidemic had been brewing for months in small villages and widened the metropolitan slums .

In addition, the definition of “highly contagious” – given by the Minister of Health of China – riferisi goes to the fact that the transmission through oral exposure and through conjunctiva is probable and has been confirmed in non-human primates (Jaax NK, Davis KJ, Geisbert TJ, P Vogel, Jaax GP, Topper M, Jahrling PB – FEB 1996) and has been demonstrated in the laboratory (Johnson E, Jaax N, White J, Jahrling P – Aug 1995) that enough drops of 0.8 -1.2 micrometers to ‘contain’ the pathogenic potential, ie the virus.
Recently, it has been shown to be transmissible from non-contact by pigs in non-human primates. (Weingartl HM, Embury-Hyatt C, Nfon C, Leung A, Smith G, G Kobinger – 2012)
It is not a coincidence Ebola and other haemorrhagic fevers have also been classified as Class A biological weapon, such as anthrax or botulism. (EK Leffel, Reed DS – 2004)

But to complicate the landscape, there are two incidents that occurred in the U.S. between 1989 and 1990.
The first took place at the Hazleton Research Products’ (HRP) Reston when they were quarantined (standard procedure) one hundred macaques (Macaca cynomolgus fascicularis) resulted affected by Ebola and sent by Ferlite Farms on the island of Mindanao, in the Philippines, via Manila, Amsterdam and New York. In that case – inexplicably as incubation period of EBO in nonhuman primates is 5-7 days – were also infected monkeys arrived 30 days later the macaques and segregated in a different area of ​​quarantine.

Six of the 178 people who had had contact with the infected monkeys showed serological evidence of infection with Ebola-Reston, but without developing a disease-related filovirus.
Out of 550 people with different levels of exposure to the monkeys (or monkey tissues or body fluids), 7.6% tested positive for at least one of filoviruses (EBO-Z, EBO-S, EBO-R, EBO-CI, MBG) but none of the 42 had a disease caused by a filovirus.
The case of the infected monkeys in the United States urged the Philippine government to monitor workers Ferlite Farms: about 186 people twelve showed serological evidence of infection with EBO-R, while forty indirect immunofluorescence test was positive, but showed no symptoms detectable.

However, at the moment, the precautions to be observed for Ebola are the same as for the other viruses that are transmitted by contact (HIV and Hepatitis C): good hygiene habits, such as hand washing and use of gloves and masks , proper management of hypodermic needles and aseptic techniques.

The Plague of Athens

According to Daniel Bausch, an expert at Tulane University School of Public Health and Tropical Medicine in New Orleans interviewed by Wired, according to which “could happen? I think so. Would turn into an epidemic too? I do not believe. The screening at airports are essential, but there would have to worry even if it were to be some chance of infection, it is sufficient that health workers should take appropriate precautions. “

Measures which, however, were used by Dr. Kent Brantly and nurse Nancy Writebol, just returned to the U.S., after contracting the infection.

Therefore, as explained to the newspaper Done Pierangelo Clerici, president of Italian clinical microbiologists : “what bothers most of this time, however, the jump is that the virus has made ​​a Guinea … it would be good that even Italy began to activate measures of attention in airports and reception centers” even if it has direct flights with countries there is officially an epidemic.

Originally posted on Demata