Frank G. Rando examines evolving biohazardous threats to global health: Where poverty thrives, disease lives.
Collectively, infectious diseases have proven to be global scourges and the single most important contributor to human suffering, morbidity and mortality throughout various periods of history. Low- and middle-income countries (LMICs) – developing nations – continue to suffer the brunt and burden of both common and exotic pathogens usually exacerbated by malnutrition, lack of access to healthcare, inadequate public health infrastructure and extremely poor sanitary conditions.
From ancient times through the Middle Ages and the Victorian period to the present day, the lethality of various microorganisms has touched everyone on Earth – from the most primitive tribes to the most sophisticated urban dwellers. Geopolitical factors, armed conflicts and civil strife have further exacerbated the health threats to these societies by generating complex humanitarian emergencies throughout several areas of the world. Many of the world’s LMICs suffer from severe conditions of impoverishment and stark health disparities when compared to wealthy, industrialised nation-states.
Sociocultural factors, such as ritualistic behaviours and practices, exotic food habits, religious beliefs and folklore often are contributory factors to the evolution of infectious disease outbreaks, such as HIV/AIDS and Ebola viral haemorrhagic fever in Africa.
Climate change, deforestation and biodiversity losses are intimately connected with the propagation of disease vectors such as mosquitoes and rodent populations. Zoonotic diseases – which result from trans-species ‘jumps’ from animals to humans – are among those infectious diseases facilitated by sociocultural and environmental changes.
The impact of human activities such as agriculture can have serious implications for both global animal and human health, as the two are inextricably intertwined and co-dependent. We see this in genetic reassortment associated with highly pathogenic avian influenza (HPAI) and with the emergence of various pathogens like the Filoviruses (e.g. Ebola strains) and the coronaviruses – which cause Middle Eastern Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS).
In Filovirus, such as Ebola, we see simian primates (monkeys) able to transmit to human primates and then direct human-to-human transmission. In the original SARS-CoV outbreak, civets in China were named as the primary culprits, and in MERS-CoV, camels served as the animal reservoir of infection capable of transmission to humans.
CORONAVIRUS: THE ULTIMATE JUMP
The pandemic caused by SARS-CoV-2, a coronavirus, is a prime example of the trans-species “jump” phenomenon. The wet markets of Wuhan, and other Chinese cities, are known for their highly unsanitary conditions and a myriad live animal species housed in crowded quarters.
These squalid conditions, focused in Wuhan, have served as the main theory for the origins of the Covid-19 pandemic and the setting for the trans-species transmission of the virus. However, controversy rages on as to the true nature of the coronavirus pandemic and its original host and infectious spread.
The theories steering away from the wet market explanation centre on serious lapses in biosafety and biosecurity at Wuhan’s regional virology laboratory, the Chinese Academy of Sciences’ Wuhan Institute of Virology. These range from an accidental release and infection of researchers – to speculation about an intentional release disguised as a laboratory accident.
What is known regarding the history and work at the Institute is its disturbing reputation as a bioweapons research laboratory and its work with highly pathogenic ‘bat viruses’ – that is, coronaviruses. Allegedly, a Chinese virologist turned whistleblower claimed to the media that the virus was modified and released intentionally which would certainly carry serious geopolitical implications.
Other emerging viral threats include as the Hendra and Nipah viruses – highly pathogenic paramyxoviruses capable of causing severe animal and human disease. The genus Henipavirus, family of Paramyxoviridae is in the forefront of infectious disease epidemiology and global public health preparedness efforts.
Henipavirus infections were first reported in the 1990s as causing severe and often fatal outbreaks in domestic animals and humans in Southeast Asia and Australia. Nipah virus infections were observed in vivo in humans in Bangladesh, India and Malaysia, where pigs were also infected. Hendra virus infections occurred in horses in the northeastern regions of Australia, with singular transmission events to humans. Flying foxes and fruit bats appear to be the mammalian contributors to the chain of infection associated with these viruses.
Hendra and Nipah viruses possess unique genetic characteristics, high virulence and wide host-agent interactions. They are designated Biosafety Level 4 (BSL4) pathogens. Infection takes horses, pigs, cats, dogs, and humans.
Widespread infection via trans-species jumps is of great concern whether a natural or intentional biowarfare or bioterrorism event, as it can devastate herds of livestock, as well as cause lethal human disease. The US CDC (Centers for Disease Control and Prevention) categorises these pathogens as ‘select agents’ with weaponisation potential, similar to other emerging pathogens such as the filoviruses and orthopox viruses (eg. Variola (smallpox).
These pathogens prefer to grow on arterial endothelial cells rather than venous endothelial cells, and also express themselves on neurons in brain tissue resulting in the occurrence of viral encephalitis in humans.
Anthropogenic influences can result in the deterioration of ecosystem health resulting in environmental conditions that promote the growth of pathogens. These include Vibrio and other water-borne diseases as well as toxic algal blooms and toxic dinoflagellates (‘red tides’) – which generate and release very powerful toxins harmful to animal species and humans.
Toxic algal blooms consist of red tides, blue-green algae and cyanobacteria, which all have severe impacts on human health, aquatic ecosystems and economic security.
Biotoxins most closely associated with toxic algal blooms are similar to the episodes in Florida, Australia, Africa and other global regions. They include microcystins, anatoxin-a, paralytic shellfish toxins (saxitoxins), lyngbyatoxins and cylindrosperopsin. These biotoxins can generate a plethora of adverse human health effects – ranging from allergic responses to severe neurotoxicity and hepatic (liver) toxicity, and organ failure in major organ systems.
Along with ricin, botulinum toxin, T-2 mycotoxins (fungal toxins), these toxins can also be weaponised as biochemical warfare agents. The potential for biowarfare or bioterrorism utilising emerging pathogens and toxins is definitely there. Even parasitic diseases that are endemic to LMICs such as helminthic infections (worms) can be used to cause parasitic illnesses among targeted populations.
The tools and methods of public health are essential in preparedness and response to a wide range of biohazardous threat agents. Biomedical research into medical countermeasures for novel and exotic pathogens and biotoxins is also critical to global public health efforts.
Continued and enhanced global surveillance employing epidemiological tools and methods, global public health education and empowerment, robust public health infrastructure, access to adequate preventive services and medical care, vastly improved environmental sanitation and addressing biopsychosocial and sociocultural factors are all needed to address these rapidly emerging health threats in this century. While countries in every continent continue to grapple with the coronavirus pandemic, their authorities will need to be aware of other looming biothreats.
CBNW US Correspondent Frank G. Rando is a national SME, trainer, and first responder with over 30 years’ experience in emergency management, tactical, disaster and special operations medicine, environmental health and safety, public safety, and counterterrorism.