Addendum to the question. Portland's methods, under the leadership of City Health Officer Dr. Esther Pohl, included fumigation of approaching ships, rat blockers clamped on all lines (ropes) on ships in port, citywide rat extermination campaign with ASAP destruction of dead rats to also exterminate fleas, waterfront sanitation, citywide sanitation, rat-proof security of food and garbage, and a politically-informed recruitment, or activation, of the entire population. Or at least a high enough proportion of the population to put pressure on nonparticipants. 

The approaches you described were probably sucsessful in limiting the exposure of humans to bubonic plague causing bacteria Yersinia pestis and thus ending the outbreak. But global or even local eradication (which I assume you mean by "exclusion"?) is unlikely, as is the eradication of the zoonotic vector - fleas, so the disease will re-occur if the population of host will have chances to grow, which will again increase human exposure to the disease. With widespread zoonotic host of the disease, the disease is unlikely to be eradicated - ever. I found reports of an outbreak as late as 1994 and sporadic cases occur probably every year around the globe. For your interest, take a look at this list of diseases, considered as candidates for global eradication: https://www.cartercenter.org/resources/pdfs/news/health_publications/itfde/updated_disease_candidate_table.pdf

You will see that there are some that have animal reservoirs, but those are tipically not easy to eliminate! Malaria would be so wonderful to get rid of, as it causes so much illness and death around the world.

In summary, preventing bubonic plague is limited to preventing exposure to it or, if one gets infected, taking effective medicines (antibiotis) to be cured. Naturally, it is not completely clear if all "great outbreaks" in the past were indeed caused by Y. pestis (note the disease can have different clinical course), but "diagnosis" is made based on description of the patients.

Let me clarify the question. Of course eradication is impossible, once Yersinia pestis reaches an area and becomes endemic. 

What the city of Portland accomplished was exclusion. A reverse cordon sanitaire, keeping all plague vectors out. Cordons sanitaire traditionally encircled towns struck by the plague, or other infectious diseases, to keep potentially infected persons from leaving. 

Portland took advantage of a rare opportunity, as the plague bacterium reached western North America from Asia. Y. pestis had entered through the port of San Francisco, and had become endemic in California. Every port city on the West coast recognized that ships from San Francisco could carry plague, and tried to implement a reverse cordon sanitaire. Only Portland succeeded. 

The evidence that Y. pestis does not exist in or near Portland is that no infection in any species -- arthropod, cat, rat, human, etc. -- has ever occurred within about 200 miles of the city.

I wonder if a reverse cordon sanitaire has ever succeeded elsewhere. 

Ok, so what you want to know is whether or not quarantine measures were effective somewhere else to prevent bubonic plague outbreak. As said earlier, we can only claim that the quarantine measures were effective in minimising human exposure. We cannot possibly claim that no Y. pestis transmission occured to the vector (if this is what you mean by "exclusion"), as there was lacking surveillance for such events at that time. (Better, but in all means no final) scientific proof of this would in modern times require capture and recapture of rats, collecting fleas and testing them for Yersinia.

Also, claiming Portland was the only city to have ever in human history achieved a sucessful quarantine for black plague would be a bit hasty, since detection and recognition of disease relied on description of the clinical disease (not actually proving Y. pestis) in the past and we can definitely assume some established quarantines might have been effective. Some more links: http://cid.oxfordjournals.org/content/35/9/1071.long

http://www.cdc.gov/quarantine/historyquarantine.html

Many European ports had quarantines for incoming ships (for example island of Minorca, Odderøya in Kristiansand etc.) and the crew was sometimes ordered to stay there for months, even years (!), but they were only partially effective because we did not understand how diseases are transmitted. "Malaise" or "bad air" was frequently blamed and the wide term was used for anything from syphilis and yellow fever to malaria. Some cities, however, remained unaffacted, either by chance or because quarantine worked - who knows.

Please note that the role of rats is continuously debated in transmission and outbreaks of Y. pestis. Infected fleas will go and bite other mammals, so the effectiveness of killing rats during the outbreak can be put under questionmark. (If some hypotheses are true, it could even trigger cases, as fleas would not have their natural host anymore and would have to look elsewhere.) One of more exciting articles on this topic: http://www.pnas.org/content/112/10/3020.full.pdf

Comments enabled here: http://theconversation.com/plague-outbreaks-that-ravaged-europe-for-centuries-were-driven-by-climate-changes-in-asia-37933

That being said, Portland can be very proud of what happened, becaue obviously, quarantine was made with better scientific understanding of disease transmission and wide introduction of disease was probably prevented (I can come with some competing hypotheses, though). No human disease or death is a remarkable achievement for the tiime before effective medicine was avaialble. Dr. Esther Pohl no doubt saved some lives.

Interesting historical period, isn't it, the early twentieth century? The science was recognizably modern. Miasma or "bad air" theories were long gone. They were surveilling rats, fleas, and people for Y. pestis, and they had Gram stain. They used Koch's postulates for diagnosis, injecting pus from buboes into guinea pigs, rats, even monkeys, to see if clinical plague developed.

I don't want to claim Portland is the only city in human history to have excluded plague. There's no way to prove the negative, that no other city has done so.

I think Portland's action saved some lives, but the real value of the achievement is proof of concept, showing that a united urban population can do that. 

I totally support you view on Portland action, though we can challenge the hypothesis by possible non-antropogenic factors, but twentieth century does come with some bitter disappointments. Antibiotics made their way into treatment very slowly, not to mention new ones are hardly being developed. And, iatrogenic transmission of HIV and HCV through needle reuse (hopefully this is now a past?) in healthcare would also be one of those major disapointments. I personally find it very indicative that anesthesia was discovered before asepsis in medicine ... major failure. We should always be aware that we are way less smart we tend to think. Even collectivelly!   

If you read French, maybe you can consult :

Patrice Bourdelais, Les épidémies terrassées. Une histoire de pays riches, Paris, La Martinière, 2003.

The thematic of the book is the history of the public health measures against epidemics, in particular plague.

You'll find there many historical litterature (in English or in French) about Italian cities and Mediterranean quarantines. For the italian litterature, see Alfani, Melengaro, Pandemie d'Italie, Milano, Egea, 2010.

Many things have also been written about the Marseilles plague in 1720-1722, and the public health measures in the city and in the Provence region. About the Marseilles system against Plague in the early-modern period, see the Phd (2013) from Jamel El Hadj (Ecole des Hautes Etudes en Siences Sociales, Paris).

As an odd coincidence,there was an article earlier this month about an attempt to research a supposed narrowly-averted introduction of plague in NYC in the 1940s:

http://foxtrotalpha.jalopnik.com/the-secret-story-of-how-bubonic-plague-nearly-broke-out-1689284222

Short version: in January 1943, the French freighter Wyoming arrived from Casablanca. As a big convoy came in that evening (sixty or seventy ships) it wasn't inspected until the next day. A (possibly forged) certificate of fumigation in Casablanca was provided by the captain and it was allowed to dock in Brooklyn and Manhattan, at which point rats were observed near the ship.  The ship was fumigated and Yersinia pestis was cultured from 15 rats and 12 fleas via guinea pig inoculation. An attempt was made to repeat tese test results but due to unspecified problems this was either not performed or not successful (there are serious problems with the lab reports at this stage). Additional trapping was performed on the piers where the ship had docked between January and May but no further cases were detected, at which point the trapping was discontinued.

The article is worth reading as it does a good job of highlighting the difficulties of confirming many of the details of this particular case.

Cool! Thanks. 

Thanks!

Historical aspects about plague epidemics  on Romanian territory.

Best regards from Constanta, Romania.

Plague was eradicated in Australia by the 1920s, and eradicated from the Hawaiian Islands by 1960. In both cases plague arrived in the late 1890s, and deliberate public health campaigns targeting infected rodents (not just the black rat) led to plague eradication.