Biological threats: what to expect?

People and infections

Infectious diseases have always accompanied humanity. And it is fair to say that our species is not unique in this regard — bacteria and viruses also affect animals and plants.

With some approximation, one could say that infectious diseases are one of the regulators of population numbers in ecosystems: when it becomes too dense, the probability of transmission from one individual to another increases significantly. Then a epidemic may begin, thinning the population, leaving the most resilient and thus preserving balance in the ecosystem.

But humans are a special kind. We have learned to think, research, and invent. Not everything, and not all at once. Humans looked into a microscope and saw microbes in the 17th century, but only by the end of the 19th century did the idea begin to emerge that hands should be washed. The beginning of the 20th century gave us, as it seemed at first, a panacea — antibiotics. A spectacular and crucial breakthrough in overcoming some pathogens was the possibility of vaccination.

As a result, over the last two hundred years mortality from infectious diseases has significantly decreased, life expectancy has doubled, and the population of humans on the planet has grown by more than seven times! Without knowledge about microbes and basic hygiene rules we would not be able to exist in such a dense population.

From smallpox, cholera, and plague to flu and staphylococcus

Massive epidemics of the past seem to have faded into the background. More effective means for their prevention and stopping have appeared, aside from burning the witch and ringing bells. We no longer fear miasmas (do we?), but we are beginning to realize the potential threat of antibiotic resistance.

And it is not surprising that in the last few decades no conceptually new antibiotic has been invented, and major pharmaceutical companies are winding down their research on development due to the lack of financially rewarding results.

And dying from plague, as well as from complications of influenza or antibiotic-resistant staphylococcus, is certainly not desirable. But can we truly bid farewell to these formidable pathogens today?

Here is cholera

This disease has taken millions of human lives in previous centuries. And today it continues to take them — albeit somewhat less. Each year up to 4 million cases of cholera are reported worldwide and each year dozens, or even hundreds of thousands, die from it. Currently cholera outbreaks have an endemic character and are recorded in African countries, India, and Caribbean islands.

Cholera outbreaks are usually predictable and preventable.

They are linked to limited access to clean water and poorly functioning, and sometimes entirely absent, sewer systems.

Interestingly, sometimes the cholera vibroin enters the body, but cholera does not develop, even though a person remains a carrier and source of infection for more than a week.

Essentially, the cholera pathogen is initially a saprophyte, so it can survive and live quite normally in the environment for a long time.

Treatment involves symptomatic therapy aimed at preventing dehydration and, in rare cases, the use of antibiotics. There are also vaccines for cholera today.

Where is it plague-like?

Before the discovery of antibiotics, plague took millions of lives and inspired real fear. But after the appearance of effective antimicrobial agents, almost everything began to hinge on rapid diagnosis, because the disease develops very quickly and death can occur within a few days of infection.

The natural reservoir of plague in nature is prairie rodents.

In the environment the plague pathogen survives quite long — in soil up to 24 days, and on domestic surfaces for three days.

Over the last ten years, more than three thousand cases of plague and more than five hundred deaths have been recorded worldwide. Mostly this occurred in Congo, Peru, and Madagascar.

In western rural regions of the United States, about ten cases of plague are recorded annually. It is believed that fleas from wild rodents transmit the infection to domestic cats and dogs, and from them, humans may become infected.

Today, proper diagnostic and accessible antibiotic therapy allow us to localize outbreaks, which occur occasionally, though they do arise.

What is a bit alarming is that some plague strains have plasmid-associated resistance to key antibiotics on which the main hopes for treating patients are placed.

Goodbye to smallpox

The highly contagious smallpox virus is able to survive in the environment for months.

The good news is that smallpox does not spread from some other source, such as an infected person. In other words, there are no other carriers of smallpox besides humans.

Therefore, vaccination really did work wonders. After the outbreak in India in 1974, when about 15,000 people died, a three-year-old girl from Bangladesh became the last person to catch smallpox naturally (she recovered). But later, in 1978 in Birmingham, a real drama unfolded — a medical professional who worked one floor above the laboratory where smallpox research was conducted developed the disease. At first, there was no suspected illness (it seemed to be overcome), and the diagnosis came too late. The horror engulfed not only the university and the city, but the international community. Emergency vaccination of everyone who had contacted the patient did not allow the disease to spread further. Thus, Mrs. Parker officially became the last person known to have died of smallpox, and the head of the laboratory, due to this precedent, took his own life.

Today the smallpox pathogen exists only in two scientific laboratories around the world. In 2018 it was officially announced the development of an antiviral prepatate and its progress for use in case of unworthy acts by potential aggressors and other unpredictable situations, as it happened in Birmingham.

Lethal anthrax

The anthrax pathogen is a bacterium belonging to the genus Bacillus. A superpower of Bacillus is its ability to form spores and thus persist in the environment for decades.

Infection occurs when spores enter the body — by inhalation or via food. The at-risk group includes people who work with animals and animal-derived products.

Good news — anthrax cannot be transmitted like influenza from an infected person.

Outbreaks are local and begin with disease and death of animals. Therefore vaccination of animals, and especially in areas where this pathogen has been recorded, is recommended.

In Ukraine, anthrax was registered in the village of Chervone and Lozovyi Yar of Yahotynskyi district in Kyiv region and in the village of Voznesenka in Melitopol district of Zaporizhzhia region.

Given the long persistence of the pathogen in the environment, anthrax is a potential threat in the hands of criminals — terrorist attempts in 2001 (letters with anthrax spores in the United States) confirm this.

Treatment of anthrax is with antibiotics. Prevention is vaccination of animals and people who may be at risk.

Underestimated today: Ebola virus

The Ebola virus is rightly considered one of the most formidable infectious threats today. The natural reservoir is animals, mainly tropical bats. Incidentally, its name owes not to a scientist named Ebola, but to the Ebola River (Zaire), near which it was first identified in 1976.

It has a high degree of communicability and a high fatality rate.

Weeks it can survive in the environment in a dried state. The incubation period can be quite long — up to three weeks.

There is no specific treatment as such. The good news — vaccines have been developed fairly recently.

And right now, while we all tremble reading news about the coronavirus, dramatic events are unfolding in Congo. In West Africa, more than 10,000 people died from this virus during 2013–2016. And the outbreak in Congo since summer 2018 continues. More than 3,000 cases with over 60% fatality.

And if it weren’t for the coronavirus, all the headlines right now would be filled with information about Ebola.

Where does it come from?

Primarily from animals.

Infectious agents persist constantly in animal populations. Not all pathogens can be contagious to humans, but some random mutation can contribute to it. It also increases the likelihood of us acquiring new infections from animals and the expansion of our own population: we occupy more and more territories where wild animals lived, with which we previously had no contact. Also, to feed billions of people, billions of livestock are raised. They are kept in dense populations and this also contributes to the emergence and spread of infectious diseases among them. Therefore it is not surprising that these infectious diseases can be transmitted to people who come into contact with them.

36 hours: from the farthest corner of the planet to most megacities

The development of transport connections is truly wonderful. It is the opportunity to travel, to explore, and to see new things. But infectious agents do roughly the same thing.

And if earlier an outbreak of some infection caused devastating impact in a particular area and did not physically spread further, now there are all the conditions for it to spread everywhere.

The incubation period of many illnesses is somewhat longer than 36 hours.

The unchanged climate changes

Such seemingly minor warming at first glance contributes to the spread of the ranges of vectors (mosquitoes, rodents, etc.) into more northern regions. Accordingly, there are risks that some diseases may cease to be endemic over time.

And about biological weapons

The use of infectious agents for illicit purposes can have not only military but also terrorist and criminal aims.

Biological weapons have a somewhat longer history than humanity’s deliberate study of microorganisms. For example, in 1300 the Tartars-Mongols during the siege of Kaffa hurled corpses of people who died of plague over the city walls.

The Japanese actively worked in the field of developing biological weapons during World War II. These were shameful pages in the history of obtaining microbiological knowledge — with experiments on humans, involving more than 5,000 people, about 600 of whom died.

There were field experiments: about a thousand wells in Chinese villages were contaminated to study the progression of cholera and typhus outbreaks. Japanese aircraft dropped fleas infected with pneumonic plague on Chinese cities. Outbreaks that occurred persisted for years and caused about 30,000 deaths. After the war, researchers were pardoned in exchange for full information about the conducted studies. Thus scientists with a slightly criminal past became respected citizens and founders of pharmaceutical companies. Some even published their work in scientific journals, replacing in the Materials and Methods section the word "human" with "monkey."

An example of research in the United States is the experimental contamination of the New York City subway with nonpathogenic Bacillus globigii, modeling a potential attack with the bacterium that causes anthrax.

Ultimately, in 1972 the Convention on the Prohibition of Biological Weapons was initiated, which obliged all participating countries to refrain from development and use.

However, this did not guarantee that participants would keep their promises. It is assumed that some countries continue their research unofficially. At the same time, countries such as North Korea, Iran, and Syria do not hide this fact.

Violations of safety procedures in such research occasionally create precedents that undermine their secrecy. For example the 1979 plague outbreak in Yekaterinburg, in which all victims fell ill in a narrow windward zone from a local military facility, gave grounds to claim development of this pathogen.

An example of biological terrorist attacks is the mailing of letters containing spores of the plague in 2001.

Biological weapons themselves are somewhat unpredictable in their consequences, and not many are eager to deal with them.

Is it time to panic yet?

Panicking is never the time. If only because it is counterproductive.

Outbreaks of infectious diseases and the emergence of new ones are expected and inevitable under these conditions. And they will occur when preparing meat of exotic animals or in large agro-industrial livestock complexes — the question is of time and chance.

The emergence of a new "unknown beast" that could trigger new outbreaks is, of course, possible. But we are not "made of different cloth" — science and medicine are rapidly developing.

And neglecting vaccinations is definitely not worth it. Because this is what can protect us from already "known beasts," but not less fierce. For example, flu and measles kill hundreds of thousands of people worldwide every year. And this could be prevented.

Also — following hygiene rules, which may sound a bit boring, but this really works.

Photo by Anna Dziubinska on Unsplash