What a fascinating story. Dan Web examines Tijuana’s murder as they skyrocketed and produced a staggering number of female victims.

This is a very compelling and well researched story that captivates you from the beginning. Great job!

I learned a lot reading this book about life and death south of the border in Tijuana. I was fascinated how the author applied his epidemiologist learning to tackle a social problem. The book can be slow going at times but there is a lot of information presented. This book is well worth a read.

Perhaps epidemiology could reveal the hidden structures lurking just beyond reach, like asbestos behind wallpaper. Those structures might manifest as cruel calamities – car crashes, murders, HIV infections – that at face value appear unrelated. If that were the case, these women were not victims of a textbook epidemic, driven by an infectious agent that could be placed in a petri dish under a microscope. There was another pathogen lurking here, protean and murderous, distributing itself across this border town’s strange environment… I was desperate to return, to understand this place, to tell the story of an epidemic that I could not yet even name.

Newly minted PhD and epidemiologist Dan Werb was determining his next steps. He connected with HIV researcher Steffanie Strathdee (recent author of a book with her husband Tom Patterson, about saving Patterson from antibiotic-resistant bacterial infection with phage therapy.) She sent Werb to Tijuana, where he became perplexed by a mysterious, growing cluster of women’s deaths beginning around 2010, connected to the city’s HIV epidemic but bigger, more sinister, and threatening to spiral out of control: “Those singular causes of death – the decision to share a needle, take that client, run across that highway – were metastasizing into something else entirely. An epidemic.”

My job, [Steffanie] explained, would be to help delineate the contours of the epidemic so that she and her colleagues could understand its spread and develop programs – behavioral interventions, social services, infrastructure, or some still unknown approach – to contain it.

Werb is thorough in documenting the burgeoning epidemic and his scientific detective work. He explains the city’s makeup, as both its own sort of American Dream-like beacon for those from provincial areas of Mexico seeking work and improvement and for Americans, to whom it “offer[ed]…escape from the moral confines that their dream had imposed.”

Tijuana was more vulnerable to the destruction wrought by HIV … it is and was a city built on sex and drugs, its economic success propelled by the human appetite for risk.

The varying purposes in this influx contributed to a rise in cartel activity, gangs, drugs, sex work, and the ugly side effects of it all — HIV, disappearance, death, murder — disproportionately affecting women. He and his team are diligent, visiting encampments to interview and help addicts and sex workers, and enlisting the help of a former sex worker and heroin user in conducting these interviews and outreach.

Werb is an exceptional writer. I don’t expect scientists to write this eloquently — at times, even poetically — while still managing to distill their research, its complications and procedures understandably. Werb achieves it, making this unusually accessible, and despite not always being easy to absorb considering the bleak topics.

Still, there is a somewhat academic or densely scientific tone in certain passages, but less than might be expected for this kind of work. I was pleasantly surprised at how accessible the majority was, but some scientific explanations and data parsing were difficult for a lay reader.

Nevertheless, elsewhere it delivers and then some. Like when he explains how influenza originated in the mid-sixteenth century in China thanks to advancements in farming techniques, making a jump from ducks to pigs and finally humans. I had to reread this passage multiple times, not because I didn’t understand but because I couldn’t believe this was what happened. He tells mesmerizingly fascinating stories. And he does his best to make it understandable and readable, likening things as dry as statistical models to good art, explaining that they similarly “reflect the world as we know it and illuminate it further.”

Werb also greatly elucidates the field of epidemiology and its workings, why it’s unique among the sciences (their laboratory being the real world), and how with an HIV epidemic, there was so much work to do in terms of perception, faced as they were with trying to “strip the disease of any tinges of morality.” This was tricky because the epidemiologists could see how bad it was, and getting worse, but officials only considered tackling it punitively, not in any way to fix underlying issues. Werb is nonjudgmental, patient, and considerate in the work, and although no easy path out is identified, there’s hope in the efforts they’ve made.

The book highlights how societal problems compounded one another, and how this isn’t Mexico’s burden alone. There was no one single factor leading to the deaths and disappearances of so many women in the Zona, the borderland between Mexico and the United States, but rather a continuously swelling storm cloud of contributors. Werb has done incredible work in illustrating this complex, multi-faceted epidemic with engaging prose, and distilling it mostly accessibly for readers. The scientific aspects are fleshed out with history, drawing connections to the border and economic influence of the US, even to folklore and myth in Mexican culture, providing deeply atmospheric insights amidst the alarming science. A timely, critical and passionate study.

The Zona nowadays is like a bruise on the body of the border, an unwanted reminder of love or violence. But the history of the place demonstrates that this epidemic is not just Tijuana’s, and the border is no separator; a mere physical barrier cannot achieve that aim… If anything, the imposition of the border along the edge of the Zona has revealed one important truth: the higher the wall, the deeper the secret.

The most famous and successful epidemiologist was John Snow. He singlehandedly stopped a cholera epidemic in London 150 years ago. He tediously marked all the unexplained deaths on a map, showing how they intensified geographically toward a central point. Visiting that spot, Snow found a public water pump. By breaking off the handle, he stopped the epidemic right then and there. Things are not usually that clear cut. In City of Omens, Dan Werb applies Snow’s and all the modern tools available to solve a current plague in Tijuana. Women are turning up dead. It is so disproportionately high he calls it femicide.

Epidemiology is detective work. It can show where our conclusions ad assumptions are wrong. Werb gives some great examples. Doctors had always thought that drug addicts were psychopaths, and assumed so when an addict showed up. That stopped when studies began to show that doctors were most liable to become addicts (as many as 50%) themselves. Similarly, American troops in Viet Nam had a heroin habit among 30% of them. Considering these situations as epidemics rather than psychiatric problems has changed the way we approach them. We’ve also discovered that bad neighborhoods don’t create addicts. Addicts drift towards them as they both decline, making both worse. The UN describes an epidemic as when a condition affects more than 10 people per hundred thousand. An epidemic becomes endemic when it is a regular occurrence, like flu in winter. The bulk of the book is about death rates in Tijuana, where murders had been closer to 40 than ten.

In the case of Tijuana, the inputs were numerous and well known: prostitution, drugs, HIV, shared syringes, corrupt police, drug cartels, violent drunks. Werb describes Tijuana as chaotic, with all of these factors applying to daily life. The pathogens were not airborne or waterborne microbes. They were corrupt people. They all involved the rapid spread of HIV, and together left a trail of bodies, literally on the streets of the city. Narcos attached notes to decapitated bodies saying let this be a lesson. Eventually, on top of everything else, there was gang war for control of the drug business. Narcotics money bought off everyone worth buying, keeping the violence levels elevated.

There is an endless supply of women streaming to Tijuana. They are attracted to the maquiladoras, the free trade zone factories that employ 200,000. The steady work turns out to be more like slave labor, and worn out women quit, going into sex work to survive. Sex work inevitably means poverty, drugs and shared needles, so disease spreads fast.


Epidemiology has another interesting aspect – it can be counterintuitive more often than not. Werb has to keep saying he was wrong. In the case of Tijuana, Werb found that increased methadone use led to decreased heroin use, which meant less spreading of HIV. Methadone costs more than heroin. The methadone use was correlated with higher bribes to police. Those who gave more to the police had better survival rates. This is not intuitive, and Werb had to figure out that people on methadone had to make more money than those on heroin, so they became bigger targets for police extortion. Overlaying the database of police beatings on maps showed clusters around the methadone centers, which turns out to be why more people did not enter the programs. This was an unexpected reason for its limited success. Nothing is simple.

Two tectonic shifts accelerated the disaster in Tijuana, Werb says. The HIV scare in the 80s caused the US Navy to send 800,000 condoms to Tijuana, because the Navy “appreciates” sex work all over the world. But the rapid increase in HIV among sailors made the Navy eventually and suddenly forbid all leave in Tijuana. San Diego County has more than 50 military bases with over 100,000 sailors, so this was big for Tijuana. Then 9/11 caused uncontrollable fear in the USA. George Bush responded with a wall 580 miles long to seal off Tijuana for some reason. Even legal border crossings fell. They dropped from their record 110 million to 71 million a year. Business in Tijuana plummeted. Sexworkers took to dealing drugs, and murders of women soared from less than ten to over 40 per hundred thousand, making it a certified epidemic.

The small irony of City of Omens is that in order to decide the global effects and origins of an epidemic, the epidemiologist spends all his/her efforts on the minutest of details. From repeatedly interviewing survivors, to examining the unique aspects of the streets, buildings, neighborhoods and environs, it is all very fine-grained. There is a lot of legwork involved. It is akin to ethnography. The biggest challenge seems to be seeing the forest while among the trees. So the book is massively descriptive, far more than one would expect from a book on epidemics. City of Omens does show the potential value of epidemiology. Unfortunately, Tijuana is not a success story. In 2018, 2300 were killed there, a rate of 135/100,000. Money talks.

David Wineberg