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Alaska's largest TB outbreak in 8 years contained on Y-K Delta

Eli Martin

Alaska authorities have confirmed an outbreak of tuberculosis (TB) in a Yukon-Kuskokwim Delta village, according to a press release Monday from the state Department of Health and Human Services. Officials said the outbreak is under control and presents no cause for alarm.

Eight active cases have been identified in the past five months in the village.  

Dr. Michael Cooper, Alaska Tuberculosis Control Officer, said that the eight individuals were undergoing treatment on-site and are all doing well. He said no fatalities have occurred during the outbreak.

“Flare-ups” of active TB cases are fairly common a few times a year in the Yukon-Kuskokwim Delta, he said. However, outbreaks tend to be concentrated more among two to four members of a household. This makes this recent outbreak the largest since 28 cases were diagnosed in Anchorage in 2006, concentrated among the city’s homeless population.

Village not identified

Both Cooper and Greg Wilkinson, public affairs spokesman for the Department of Health and Human Services, declined to identify the village at the center of the outbreak. 

Cooper said that unless the public faces an immediate danger from an outbreak of illness or disease, state authorities would rather not risk stigmatizing a community by identifying it as a source of prior contagion.

“The main reason for putting (the press release) out is we want show that we are on top of this,” Cooper said Monday. 

He said there is no elevated risk of contracting tuberculosis in the community due to intensive treatment and was adamant there was no cause for panic.

Wilkinson also said that once a small community is identified as a source of TB, it becomes relatively easy for its inhabitants to pinpoint the afflicted individuals or family. Alaska’s Infectious Disease Program follows a strict policy of not violating patients’ privacy.

Historic epidemic years ago

Tuberculosis outbreaks in rural Alaska aren’t new.

In the 1940s and 1950s, Cooper explained, tuberculosis was rife in Alaska, and concentrated among Alaska Natives. The Yukon-Kuskokwim Delta had what may have been the highest rate of the disease anywhere in the world. Between 1948-51, skin tests conducted on children estimated that 89 percent of the population tested in the southwest region were infected with tuberculosis.

Beginning in the early 20th century, a combination of factors created what Cooper called a “perfect setup” for TB to spread like “wildfire” in rural Alaska. These included remote geography, poor healthcare infrastructure, increasingly crowded living conditions, and an influx of non-natives who brought with them weakening diseases like measles and flu, against which Natives had no immunity.

A major response effort, which included extending previously limited health care to rural Alaska, helped bring the epidemic under control and rates of infection have plummeted over the years. Cooper could not estimate how many Alaskans were infected today, but said that the rate was probably in the low single digits.

But tuberculosis did not go away.

Today, the legacy from the first half of the 20th century presents itself in the form of latent carriers of TB, individuals who are infected but do not actively suffer or show symptoms of the illness. Latent carriers cannot pass on the disease to family or other village residents, either through physical contact or through the air.  

They can, however, develop active tuberculosis -- particularly as aging weakens the immune system -- a half-century after becoming infected with the bacteria. And at this point, the disease can become contagious and rapid treatment is needed.  

Poor living conditions in rural Alaska

This “historic basis,” Cooper said, constitutes the biggest factor in the occurrence of new active cases in the 21st century. Many of the same conditions that initially made tuberculosis such a problem among Native Alaskans remain factors in 2013. These include crowded living conditions, lack of access to running water, and the paucity of good quality medical care in remote villages.

Each case of active tuberculosis, which can be fatal, requires an extended period of treatment, usually about six months.

And while infected persons usually do not have to be transferred to regional hospitals -- in this case in Bethel or Anchorage -- the length of treatment and inaccessibility of many villages combine to present a significant challenge for public health authorities.

Highest rates in America

In 2012, Alaska had the highest incidence of new active tuberculosis cases in the United States. There were 66 new cases, and a rate of nine cases per 100,000 Alaskans. Alaska Natives constituted 69 percent of the state’s cases. The state’s southwest region, which includes the Yukon-Kuskokwim Delta area, saw 66.6 cases per 100,000 people.

By comparison, the average rate of new cases in the United States as a whole was just over 3 per 100,000 inhabitants.

The 49th state also reported the highest incidence in 2011, and tends to come first or second each year, swapping places with Hawaii.

Nationwide, Alaska bucks one trend distinctly. Across the US, the majority of most new active cases originate in the foreign-born population, with countries like Mexico and the Philippines being the place of origin of many infected individuals.

In Hawaii, which featured the second-highest incidence in 2012, 90 percent of new cases were among the state’s foreign-born population, the result of migration from the Pacific islands and East Asia.

Foreign-born individuals accounted for 62 percent of all new cases in the US in 2012.

A TB-free future?

Such figures provide another example of how Alaskan Natives, who account for more than two-thirds of new TB cases in Alaska but only 15 percent of the population, face challenges not shared by other Americans. Cooper was optimistic that Alaska’s infection rates would improve over time as the state identifies and treats latent cases. Over time, people alive and infected during the period up until the 1950s will also gradually pass away.

But Cooper cautioned against expecting the eradication of tuberculosis in Alaska. The historic scourge of rural Alaska remains a potential killer. In 2012, public health authorities attributed three deaths to be related to tuberculosis.

Contact Eli Martin at eli(at)alaskadispatch.com