In Dark Winter, epidemiologist and biosecurity expert Professor Raina MacIntyre shares insights into the history of biological attacks, lab accidents and epidemics – as well as the COVID-19 pandemic.

She alleges a recurrent theme of denial, silence and cover-up around unnatural epidemics and the powerful vested interests at play.

In this extract, Professor MacIntyre explores what she looks for to distinguish between outbreaks with a natural original and those with a human hand behind them.

Being able to identify and analyse unnatural outbreaks is essential for the effective management of epidemics. This critically important point is one that I always drive home to my students. In a course I designed at the UNSW entitled ‘Bioterrorism and Health Intelligence’, I take students through an outbreak of salmonella in the US. The exercise uses as a case study a real outbreak, and I provide sequential data on it, along with the conclusions of the Centers for Disease Control and Prevention and local public health authorities.

I ask the students to analyse the outbreak and make their own conclusions. The circumstances are as follows: in 1984 hundreds of people in a city in Oregon started getting sick with gastroenteritis. All the patients had eaten in at least ten different restaurants. I walk the students through the investigation.

We look at the pattern of foods eaten by those who did and did not get sick, but there is no common ingredient or food – not the eggs, or the milk, the water supply or any other product. The inspection of affected restaurants show sanitation, water and food preparation to have been reasonable.

All of the restaurants had a salad bar, and in ones that served the same food in private dining rooms, only people who ate from the public salad bar got sick. The outbreak strain of salmonella was an unusual one, quite different from other salmonella outbreaks seen in Oregon.

With over 700 cases, it was the biggest outbreak the US had seen to date. Local health authorities called in the Centers for Disease Control and Prevention for assistance.

The outbreak experts concluded that unsanitary food handling was the cause. This is not surprising. After all, anyone who works in outbreak investigations knows that salad bars are notoriously unsanitary and often associated with outbreaks. As a trainee field epidemiologist with the Victorian Department of Health and Human Services in the 1990s, I investigated many salad bar outbreaks myself.

The inside knowledge I gained during those investigations make me wary of ever eating from a salad bar. The circumstances were often stomach turning. In one case, potato salad was revealed to have been contaminated with faecal bacteria. In another famous outbreak in the US, a disgruntled kitchen hand who had Hepatitis A but was asymptomatic, urinated into the coleslaw as revenge, causing an outbreak of the virus.

In Oregon, following the salmonella outbreak, the restaurants were shut and the outbreak ended. Case closed. At this point in the case study exercise, the students mostly tend to agree with the Centers for Disease Control and Prevention about the origin of the epidemic.

I ask them why they agree, when the inspections had shown that sanitation in these establishments was okay. Were the cooks unsanitary in all ten restaurants? What else could explain an outbreak affecting ten different restaurants, I ask? Why did people eating the same food in private dining rooms not get sick?

Our discussions touch on the particular response of politician Jim Weaver, who insisted at the time that it was a bioterrorism attack by a local cult. He was laughed at and shouted down by the Centers of Disease Control and Prevention and the public health experts in Oregon. Convinced, Weaver went to the media with his theory, and was ridiculed by the public health folk and labelled a conspiracy theorist.

Most of the students in my class agree that Weaver was a crazy conspiracy theorist. Anything outside our accepted reality or knowledge base must be a conspiracy, surely? And yet the facts before us are clear: ten different restaurants affected and sanitation and water were fine.

There was no common ingredient that could explain the outbreak. Deliberate contamination is clearly a possible explanation, but why is it so hard to see it? And why is anyone like Weaver, who suggests the possibility ridiculed and shouted down?

Picture: UNSW

Whenever I teach my Bioterrorism and Health Intelligence course, I always remind students that in order to detect unnatural outbreaks, you must first ask the question ‘Is it natural or unnatural?’ The reason that we need to know if epidemics are natural or unnatural is that it determines the course of action.

In both cases, public health measures are put into action, but in the case of an unnatural outbreak, further specific action may be needed, including finding the perpetrator (or perpetrators) in order to prevent further attacks and bring them to justice.

About six months after the Oregon salmonella outbreak, cult leader Bahgwan Sri Rajneesh admitted that his cult had poisoned the restaurants. But no one believed him. This reluctance surely illustrates a hard wired recalcitrance to accepting the possibility of unnatural outbreaks.

It begs the question: how hard is it for health experts to recognise an unnatural outbreak when even a confession is not believed? In the end, evidence confirmed Rajneesh’s confession. Quite by accident, a year after the outbreak, while conducting an immigration raid, the FBI stumbled on the Rajneesh lab on their sprawling ranch.

The cultures of salmonella found in the lab were determined to be an exact match to the rare outbreak strain. That was the final evidence – forensic evidence collected by the FBI, without a single contribution from health experts.

This failure in public health was not due to a lack of availability of technical experts. Indeed the US Centers for Disease Control and Prevention arguably boasts the greatest concentration of technical experts in the world. But technical expertise without the ability to break the shackles of dogma, ideology and group-think is as good as useless.

It was not until a full 12 years after the event that the findings from the Rajneesh case were talked about and made public. My students, just like the public health officials at the time, cannot think of a reason why anyone would choose to engage in such an act of bioterrorism, and so cannot believe it.

Occasionally, a student analysing the outbreak on the face value of the facts will come to the conclusion that ‘it’s unnatural’, but the majority of students do not. They cannot think of a motive and cannot imagine the unimaginable. In the end, the actual motive turned out to be political.

The Rajneeshis were in conflict with the local government about a land issue and were running their own candidates in the local election. They had tried to register their 4000 or so cult members to vote, including homeless people they had collected off the streets of Portland, but this backfired and was disallowed. So their plan B was to poison the town water supply to make the locals too sick to vote on election day, thereby winning the election and taking control of the town. The restaurant attack was their practice run.

The Rajneesh salmonella attack in Oregon in 1984 exemplifies the failure of public health when it comes to recognising unnatural outbreaks. All of the elements – the failure to even ask the question as to whether the cause was natural or unnatural, the overriding of clear red-flag evidence with beliefs, and the labelling of anyone who suggested it was an unnatural cause as a conspiracy theorist – prove how hard it is to expose the origins of an unnatural outbreak.

The Rajneesh case showed also that even a confession (which is a rare occurrence in both deliberate attacks and lab leaks) is not enough for health authorities. Given these barriers, what hope then is there for ever detecting unnatural outbreaks?

The problem is that the investigation of unnatural out breaks requires the skills of police or intelligence analysts, not health experts. There is little collaboration between disciplines, except in some notable cases such as the US anthrax attacks in 2001.

In that case, when it became clear the strain of anthrax had likely come from a US military laboratory, the FBI and Centers for Disease Control and Prevention collaborated in a joint investigation. In contrast to the Rajneesh salmonella attack, however, the outbreak was clearly unnatural, caused by anthrax being mailed in envelopes complete with threatening letters purporting to be from terrorists to several people shortly after the September 11 Twin Towers attack.

In terms of ascertaining origins, however, the most challenging outbreaks are the ones that spread from person to person. This is because once an outbreak starts spreading, a highly contagious disease pattern will look the same whether the origin was natural or unnatural.

The Rajneesh case was not spread from person to person. Rather it was what we term a ‘point source outbreak’. The origin of such cases is usually a common source such as food, water or the environment. In the Rajneesh case, it should have been easy to pick the outbreak as unnatural, but ingrained biases and lack of training produced a barrier to effective and accurate identification of causation.

In order for transformational change to occur, we need public health experts instilled with forensic and criminal investigation skills as undergraduate students, so that if they ever encounter the health effects of an unnatural outbreak, they are able to think outside the square.

Historically, very few unnatural outbreaks have been correctly recognised as such at the time. A classic example of this is the notorious lab leak from the Soviet bioweapons facility at Sverdlovsk (now Yekaterinburg), east of the Ural mountains.

One night in 1979, so the story goes, a technician at the Soviet bioweapons facility forgot to replace a valve in the ventilation system, resulting in weaponised anthrax being accidentally pumped out into the town all through the night.

Other reports suggested there had been an explosion at the bioweapons factory and thousands had died. The official death toll was closer to 100, but to this day no one knows the true number of deaths. People died of inhalational anthrax up to 4 kilometres away from the site and by some reports as far as 50 kilometres away, showing how far anthrax spores could disperse in the wind.

This is an extract from Dark Winter: An insiders’ guide to pandemics and biosecurity by Professor Raina MacIntyre (NewSouth Publishing, $32.99). Out now.