Biological weapons are using infectious agents or biological toxins to infect organisms with the intent of harming or killing them. These weapons are viruses or living organisms which replicate, and have the ability to infect a single or multiple humans. These weapons are used offensively. Defensively used against these weapons are countermeasures that involve recognition, diagnosis, and treatment of the disease (Newman, 2018).

There are many possible ways of exposure of exposure to biological agents, including bombs and grenades containing the agent, aerosol sprays, brushes for contaminating surfaces, by injection, and by food contamination (CDC, 2015). According to Johns Hopkins Centre for Public Health Awareness (n.d), there are three classes of potential biological weapons: A, B, and C. The classifications are ranked in order of severity of the potential health impact based on the type of agent, mode of delivery, lethality, and potential to cause disruption.

Class A biological weapons are given the highest priority. This is because they have the highest potential for dissemination and can cause the highest mortality rates in comparison to class B or C. Additionally, they require the greatest amount of public health preparation. A popular example of a class A biological weapon is Anthrax, however there are many others listed such as; botulism, plague, tularemia, small pox and viral hemorrhagic fevers (CDC, 2015).

Anthrax is a serious infectious disease caused by Bacillus anthracis bacteria. The bacteria is rod-like, as shown in Figure 1, and forms bacterial spores, commonly affecting wild animals through contaminated soil and water. Humans contract the disease through consumption of contaminated animal products. Anthrax is rare but is more common in countries that do not have public health programs that routinely vaccinate animals against anthrax (CDC, 2015).

Figure 1. Rod-like Bacillus anthracis bacteria (Infection Landscapes, 2013)

After WWII, 103 countries signed a treaty designed to eliminate the use of anthrax as a weapon. However, some countries and terrorist groups still develop B anthracis as an agent of mass destruction (CDC, 2015). The true extent of the threat of anthrax is difficult to evaluate. The production of the agent is extremely difficult due to the size and number of spores required to cause an outbreak, and many previous attempts have been unsuccessful. (Tasota, Henker, and Hoffman, 2002).

Pathogenesis

When inside a host organism, the bacterial spores can reside in macrophages and takeover the lymph nodes. The mature bacteria then prevent phagocytosis and freely move around the lymphatic system. The spores can also release edema toxin, affecting water balance and causing swelling. Furthermore, lethal toxin release can stimulate tumour growth factors and cause massive hemorrhage. Thus, these toxins can rapidly cause respiratory distress, sepsis, and meningitis (Tasota, Henker, and Hoffman, 2002).

Class B contain biological weapons that still pose a threat but to a lesser extent than class A. They will result in lower amounts of mortality and require less public preparation. An example of a Class B agent is Salmonella or any other food safety threat (CDC, 2015).

Salmonella is one of many types of food-borne illness. Common symptoms of salmonella are nausea, vomiting, and diarrhea. Symptoms can sometimes be severe and even be life-threatening, especially if an individual is vulnerable to infection, such as pregnant women and children (CDC, 2018).

Pathogenesis

Salmonella enters the body through food ingestion. However, there are certain requirements for salmonellae to be fully pathogenic. It must have the ability to invade cells, replicate intracellularly, release toxins, and a complete lipopolysaccharide coat. This is a coat that is comprised of fats and carbohydrates and it helps induce an immune response in animals (Raetz & Whitfield, 2002). After passing the gastric acid barrier, it invades the mucus membrane of the small and large intestines and produces toxins. The mechanisms that explain how the epithelial cells are invaded are not fully understood. However, invasion does require an initial binding to specific cell receptors on surface of the intestinal epithelial cells. The initiation of invasion is marked by the pathogen irritating or ‘ruffling’ the intestinal lining cells. That ends up causing pinocytosis of the pathogen. Pinocytosis is also referred to as ‘cell drinking’ where small particles are brought into the cell (Holter, 1959).

After invasion, the epithelial cells release proinflammatory cytokines (Gianella, 1996). Cytokines simply regulate host responses to invasions, infections, immune responses and trauma. Proinflammatory cytokines promote inflammation and can often aid in disease progression. In the case of salmonella, this inflammatory response causes diarrhea and can even lead to ulceration and destruction of the mucus membrane. The salmonella bacteria can also leave the intestines and go on to affect many other organs and tissues (Dinarello, 2002).

Class C contain biological weapons that are not considered as significant of a threat as class A or B. They have the potential of leading into cases of morbidity. There is not as much of an emphasis put towards public health preparation with this class, only non-specific preparedness. An example of a class C agent would be hantavirus.

Hantavirus is a rodent-borne enveloped RNA virus which is often found in their urine, saliva or droppings (Schmaljohn et al., 1985). It can be transmitted through inhalation of saliva or urine droplets, it can also be acquired through the dust of their feces (Yi., 2013). If contaminated material is able to enter the body, then transmission is likely to occur. A disease caused by Hantavirus is Hantavirus pulmonary syndrome (HPS). Symptoms of this disease show within 1-5 weeks of infection, they affect the lungs and can result in severe respiratory failure and death (Safronetz, 2014). Another common disease caused by this virus is Hantavirus hemorrhagic fever with renal syndrome (HFRS). This is also known as korean hemorrhagic fever and its incubation period is roughly 2 to 4 weeks (Markotic, 2002).

Pathogenesis

There is not a full understanding of the pathophysiology of HPS, this is mainly due to the lack of disease models to experiment on. However, recent studies have attempted to investigate the pathogenesis of the hantavirus in order to gain a better understanding of it’s fatal consequences and modes of actions. It is hypothesized that the viruses disease progression is related to damaging host immune response (Safronetz et al., 2014).

Another study investigated both HPS and HFRS and have concluded that both diseases result from defects in blood vessel permeability and platelet function (Mackow et al., 2001). They have found that beta-3-integrins increase risk of the diseases. Beta-3-integrins are a class of receptor proteins involved with adhesion, they play a critical role in regulating vascular permeability and platelet activation and these receptors can be used by hantavirus to promote pathogenesis (Mackow et al., 2001).

Biological agents were recognized for their potential to be used as warfare weapons as early as 600 BC (Riedel, 2004). Rudimentary biological weapons included the use of filth and cadavers, infected animals, and contagion to attack and weaken enemies (Robertson & Robertson, 1995). Polluting wells and contaminating the water sources of the opposing party was one of the most common strategies used throughout many European wars and the American Civil War.

Leaders in the Middle Ages realized that the victims of infectious diseases themselves could also be used as military weapons (Riedel, 2004). During the siege of Caffa (now Feodosia, Ukraine), in 1346, the attacking Tartar force was attacked by an epidemic of plague. The Tartars took advantage of this setback by hurling the bodies of their deceased into the city, initiating the spread of the plague within the city and forcing the besieged Genoans to flee.It is believed that Italians fleeing from Caffa carried the plague into the Mediterranean seaports; ships carrying plague-infected refuges sailed to Venice, Genoa, and many other seaports, contributing to the second plague pandemic (Norris, 1977). The plague pandemic, also known as the Black Death, went on to become the most devastating public health disaster in human history. Though the assumption that a single biological attack was the sole cause of the epidemic in Caffa and even the 14th century plague pandemic may be an oversimplification, it is a powerful reminder of the devastating consequences of using infectious diseases as military weapons.

However, the use of biological warfare did not stop there. During the same 14th-century plague pandemic, many other incidents indicated the continued use of contagion during war. For instance, the corpses of dead soldiers were hurled into the ranks of the enemy in Karolstein in 1422. The cadavers of plague victims were also utilized in 1710 by Russian troops to fight against the Swedish forces in Reval.

Smallpox is another disease that was used effectively as a biological weapon during the 15th century. It is believed that with the discovery of the New World, an expedition to South America in the 15th century lead to the distribution of variola-contaminated clothes to South-American natives (Robertson & Robertson, 1995) (Christopher, Cieslak, Pavlin, & Eitzen, 1997). In addition, smallpox-laden blankets were also used during the French-American War (1754 - 1767) to diminish the native Indian population hostile to the british. As a result, a devastating outbreak of smallpox occurred among the Native American tribes of Ohio River Valley (Christopher et al., 1997; Henderson et al., 1999).

During the past 2000 years, major incidents utilizing biological agents in the form of diseases, animal carcasses and human cadavers have been noted below:

• 600 bc Solon uses the purgative herb hellebore during the siege of Krissa + when the Assyrians poisoned enemy wells with rye ergot (a fungus disease)
• 1155 Emperor Barbarossa poisons water wells with human bodies in Tortona, Italy
• 1346 Tartar forces catapult bodies of plague victims over the city walls of Caffa, Crimean Peninsula (now Feodosia, Ukraine)
• 1495 Spanish mix wine with blood of leprosy patients to sell to their French goes in Naples, Italy
• 1710 Russian troops catapult human bodies of plague victims into Swedish cities
• 1763 British distribute blankets from smallpox patients to Native Americans
• 1797 Napoleon floods the plains around Mantua, Italy, to enhance the spread of malaria
• 1863 Confederates sell clothing from yellow fever and smallpox patients to Union troops during the US Civil War
• World War I German and French agents use glanders and anthrax
• World War II Japan uses plague, anthrax, and other diseases; several other countries experiment with and develop biological weapons programs

The phenomenon of biological warfare became more sophisticated during the 19th century after significant advancements within the field of microbiology. The development of modern biotechnology allowed for the production and isolation of specific disease-causing pathogens.

Substantial evidence suggests the development of a covert biological warfare program in Germany during World War I. Reports indicate the attempts of Germans to ship horses and cattle inoculated with disease-producing agents such as Bacillus anthracis (anthrax) and Pseudomonas pseudomallei (glanders) to the United States and other countries (Hugh, 1992). The same bacteria were also used to infect sheep that were destined for export to Russia. Allegations of attempts by Germany to spread plague in regions of Russia and cholera in Italy were also made (Hugh, 1992). In response to the terrible effects of the chemical and biological warfare used during World War 1, the Geneva Protocol was signed in 1925 to prohibit the use of weapons of mass destruction (Kadlec, Zelicoff, & Vrtis, 1997). However, since the protocol did not address verification or compliance, many countries began developing bioweapons soon after its ratification.

During World War II, several countries including the US, United Kingdom, Canada, Germany, Japan, and the Soviet Union were involved in leading biological warfare research programs. Japan conducted biowarfare research from 1932 until the end of World War II; over 10,000 prisoners are believed to have died as a direct result of experimental infection by agents causing anthrax, cholera, dysentery, gas gangrene, meningococcal infection, or plague (Christopher et al., 1997; Kadlec et al.,1997). . Experiments also included research on tetrodotoxin, an extremely poisonous fungal toxin. In later years, Japanese officials declared these experiments as “most regrettable from the view point of humanity” (Harris, 2002).

In addition, the Japanese military developed plague as a bioweapon by allowing lab grown fleas to feed on plague infected rats; the fleas were released over Chinese cities via aircrafts over several occasions to initiate devastating plague epidemics (Harris, 2002). However, the Japanese were not adequately prepared for the use of this biological weapon; out of the 10,000 casualties that occured due to biowarfare, 1700 of these deaths were reported to have occurred among Japanese troops (Harris, 2002).

The Soviet Union was also accused of experimentation with biological weapons, referring to examples of various infectious organisms recovered from Russian spies (Harris, 1992). In addition, Germany also initiated a biological weapons research program and participated in experimental studies on prisoners; however, it is believed that the biowarfare research never officially materialized (Harris, 1992).

On the contrary, German officials accused the British of attempting to introduce yellow fever in India, using infected mosquitoes (Riedel, 2004). The British were also reported to be involved in experimentation with at least one biological agent: B. anthracis. In addition, British military scientists carried out bomb experiments of weaponized spores of B. anthracis on Gruinard Island near the coast of Scotland (Riedel, 2004). The experimentation lead to heavy contamination of the island, rendering it uninhabitable for decades after (until decontamination in 1986). In the USA, an offensive biowarfare program was initiated in 1942 looking at organisms of interest such as B. anthracis and Brucella suis. However, due to inadequate engineering safety measures, a large-scale production of biological weapons was precluded (Robertson & Robertson, 1995; Christopher et al., 1997).

When it comes to the usage of biological weapons, numerous ethical and safety concerns arise. As technology continues to progress, the risk of biological weapons being used by non-state parties, individual, or terrorist groups becomes more of a prevalent issue. The use of biological weapons for criminal acts, targeted assassinatiions, or the unintended release of harmful biological agents are indeed possible. (UNOG, n.d.) Without implementing proper policies, safety measures, and regulations, the likelihood of such criminal or negligent use of biological weapons increase. In a real-world situation, it is difficult to differentiate between the causes for biological weapon usage. When there is an occurence of biological warfare, a network of organizations are involved to mitigate the effects of the biological event. Managing the risks, preparing for damages, or preventing the biological event from happening in the first place is multidisciplinary, multi-sectoral, and coordinated. (UNOG, n.d.) International, regional, nongovernmental organizations, and other nonproliferation regimes coordinate to respond to biological threats in an optimal manner to ensure safety of as many people as possible. (UNOG, n.d.)

The Biological Weapons Convention (BWC) was established in 1972, to aid with the existing initiatives dedicated to control for the occurence of biological events. (UNOG, n.d.) These established initiatives include the 1925 Geneva Protocol, the Convention on the Prohibition of the Development, Production and Stockpiling of Bacteriological (Biological) and Toxin Weapons and on their Destruction. (UNOG, n.d.) The BWC was the first multilateral disarmament treaty. (UNOG, n.d.) The treaty prohibited the development, production, acquisition, transfer, stockpiling, and use of weapons under the biological and toxic category. (UNOG, n.d.) The BWC State parties meet a few times every year in order to maintain the efficacy of these biological safety-, and prevention measures, as well as the BWC’s key provisions.

Canada is amongst the 170 States to sanction the Biological Weapons Convention, with the government of Canada taking the responsibility to act against biological threats. (Government of Canada, 2018) The Canadian government has implemented multiple laws pertaining to biosafety, biosecurity, non-proliferation, and control of biological materials. (Government of Canada, 2018) As a means of risk management, the Canadian Public Health Agency has implemented the Human Pathogens and Toxins Act to mitigate biological threats. Canada also has a program dedicated to ensuring biological security; helping to identify, prevent, or respond to biological outbreaks. This program, Canada’s WMD Threat Reduction Program, has a multi-disciplinary network that aids in implementing the Convention in other nations. Though there has been no means of checking to see if State Parties’ comply to their treaty obligations, States have agreed to complete an annual CBM, Confidence Building Measure. (Government of Canada, 2018) The CBM serves to enhance compliance, cooperation, and trust within all State Parties.

The World Health Organization (WHO) has implemented logistical processes to counteract the effects of biological threats on human health. From epidemiological investigations, to patient care, to the handling of the pathogenic threat, WHO is prepared to respond. (WHO, 2019) In terms of treatments, such is dependent on the source of the biological threat. Standard procedures have been implemented for known infectious diseases. (WHO, 2019) Oftentimes, infected individuals are quarantined, infections are isolated, and information is shared to nullify the biological threats. (WHO, 2019)

Historical attempts of using diseases in biological warfare illustrates the difficulty of differentiating between a naturally occurring epidemic and an alleged or attempted biological warfare attack—a problem that has continued into present times.

These weapons will become more common in the next decade and has caused a greater amount of research in the United States for defensive weapons by the Combat Weapons of Mass Destruction unit. Supercomputer modeling is a tool that has been used to model the conditions for how the weapon behaves to its environment, and use this information as a defensive strategy. Microbial forensics are another huge field used as a defensive strategy (Demirev, Feldman, & Lin, 2005). Using this method, the scientists can reverse engineer the pathogen and observe the way that it was created. A way to increase defensive strategies is through developing better instruments that can lower the cost of use, be more automated and have a higher sensitivity, but this could also result in more dangerous offensive weapons. However, an increase in defensive weapon technology has a two fold application where researchers are also able to use this information to combat other common diseases such as bird flu (Demirev, Feldman, & Lin, 2005). This has caused the creation of remote and biological agent point sensors. Mostly all remote sensors detect chemical or biological aerosols with some having the ability to detect pathogens up to 10 kilometers away. These machines have a low specificity meant for quick detection and collect information such as cloud density and spatial distribution. The most promising form of biological point sensors is nucleic acid-based sensors. However, using this type of sample requires you to have a sample to test rather than just a general area like remote sensors. Nucleic acid sensors amplify DNA using PCR and map out the genomes for specific common threats. After having this model created, the scientists are able to compare their sample to one of the genomes mapped out, and use this to identify what pathogen is present (Demirev, Feldman, & Lin, 2005).

The new offensive weapons are primarily being engineered for harder detection and treatment. Another possibility is that the pathogen can disguise itself as something else preventing easy diagnosis by a healthcare professional. Biological weapons may become more customizable in the future, being able to target specific areas of a person, and creating a predictable result (Petro, Plasse, & McNulty, 2003). One researcher stated that countries may only be five years away from scientists creating a pathogen for a certain group that has a low chance of being detected before it has already spread in that population. There is also the idea of “stealth” viruses which would be introduced into the genome of a certain population, and trigger a disease through a specific signal. There could also be “designer” diseases where cell death could be triggered throughout the body based on the multiple pathways that it effects. Weapons could be created based off of plant inoculants which are currently used in agriculture, or even use worldwide databases which contain the genetic information of different populations (Fraser & Dando, 2001).

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