The squalor of LA’s skid row and the dangers it poses to human health took center stage briefly last fall when the director of one of the city’s largest homeless shelters contracted a flesh eating infection caused by e coli staph and strep that now threaten the amputation of his leg below the knee.

Rev. Andy Bales, who has directed the Union Rescue Mission for 11 years, said that he contracted the infection while walking on the street wearing a gauze-covered boot over a foot wound. Bales, a diabetic, used the incident to sound an alarm about health conditions on skid row, calling the crowding and unsanitary conditions a public health emergency.

“We need to have a holy indignation about anyone living on the streets,” Bales said, as he sat in his office in obvious pain some six months later.

Homelessness is on the rise across Los Angeles, in part because of skyrocketing housing costs. Last year’s homeless count showed a 16 percent increase from 2013 with more than 40,000 people estimated to be on the streets in LA County. This year’s count is not yet complete. But skid row’s population has exploded, nearly doubling in the past two years by Bales’ estimate.

A downtown development boom has brought pricey lofts, condos, nightspots and galleries to the center of the city and pushed homeless people into skid row, an area of some 40 city blocks where tents, cardboard boxes and people sleeping in the open air still line the sidewalks.

Even though shelters, soup kitchens and social service agencies dominate the neighborhood, there are more people than shelter beds, and many people who simply refuse to go inside.

People live their lives on the street in close quarters where sanitation is spotty. Rats scurry about.

“It is an emergency because so many people are out there,” said Susan Partovi, a primary care physician who does outreach to skid row residents.

Partovi said 10 of her patients died in the last year, more than in her entire 22 years of practice, she said.

“As a primary care doctor, you don’t have a lot of deaths…maybe one a year.”

The average life expectancy of a homeless person is about 47, Partovi noted, compared to 78 for Americans in general.

Partovi said the greatest health threats to homeless people are diabetes, COPD (chronic obstructive pulmonary disorder), and high blood pressure, the same conditions that endanger more affluent people. Still, among the homeless many of those illnesses are uncontrolled. And unlike even low-income people who have homes, the circumstances of the lives of the homeless make them more vulnerable to contagious disease.

For many, common conditions can be killers, according to officials at the Los Angeles County Department of Public Health.

Influenza, for example, is a big concern for homeless people who live in crowded conditions because it’s spread by breathing, sneezing or coughing, said Benjamin Schwartz, a physician who serves as deputy director of the agency’s Acute Communicable Disease Control program.

“We would doubt that people on skid row are vaccinated,” he said

Public health officials record tens of flu deaths each year, Schwartz said, but there are actually hundreds or thousands of them, he said, because flu complicates heart or other respiratory conditions.

Similarly, Schwartz said he’s concerned about pneumonia, tuberculosis and pertussis or whooping cough, which can spread in similar ways as flu. Whooping cough cases are on the rise in Los Angeles County, and booster shots are recommended every ten years for adults, a recommendation Schwartz said few on skid row likely heed.

The LA County Department of Public Health tracks pneumonia and whooping cough cases, but not by homeless status or block-by-block. The same is true for staph and strep infections of the sort that that Bales contracted. Therefore it’s impossible to know whether the number of those infected is greater on skid row, or among the homeless in general.

Public health investigators do make note when they identify a homeless person with tuberculosis because the homeless have been particularly vulnerable to the disease. In 2013, the last year for which data are available, 66 homeless people were reported to have TB, representing about ten percent of all cases the public health department tracks.

Mary Marfisee, a doctor who serves as medical director for the UCLA School of Nursing clinic inside the Union Rescue Mission shares Schwartz’s concerns. She said she’s seen some rare conditions on skid row, including a bone infection, tetanus in adults and a case of diphtheria, and she treats TB and skin infections that are characteristic of homeless patients.

But in most patients, it’s chronic illness and low resistance that plague clinic clients.

“They don’t fight infection well,” Marfisee said of her homeless patients. “It’s not simply because of the elements. It’s also poor nutrition, poor hygiene, overcrowding and they’re always stressed.” What is more, years without regular health care have taken a toll, and in some patients the damage is irreversible, she said.

Still better health is now within reach of many on skid row, since medical insurance through the Affordable Care Act is now available, noted both Marfisee and Partovi.

But it’s not easy for homeless people to restore their health, and some seemingly simple and potentially life-saving fixes still elude them.

“If we had ten thousand dollars, we’d buy the adult pneumonia vaccine,” Marfisee said. “We don’t have the money for it.”

She said that she’s currently strategizing ways to get the vaccines funded.

The other potential paths to better health for homeless patients are more difficult, Marfisee said.

She puts building self-esteem at the top of the list, because with confidence comes caring about one’s wellbeing and the strength to beat addiction. It’s also key to navigating the system to get the services necessary to get back on one’s feet.

Ongoing so-called wraparound services that are easier to access are also necessary, Marfisee said.

As homelessness reached a crisis point last year, with people camping under bridges and in parks in neighborhoods where encampments had never before sprung up, both county and municipal officials adopted plans last month that call for heavy investment in permanent housing.

The county has launched outreach teams that include medical professionals and social workers to find people on the streets, fill their immediate needs and get them housed as soon as possible. In addition to the obvious fact that housing construction isn’t keeping pace with need, outreach is tough, laborious work, Partovi said. It may take days or weeks to convince one person to take initial steps to get off the streets; sometimes people backslide or change their minds. Partovi said she employs creativity and occasionally, extreme measures to help her patients.

She described one woman who lived at the edge of the LA River with five cats. Although the woman needed cancer treatment and recuperative care, she was reluctant to enter a facility and leave her animals. After some negotiation, Partovi came up with a solution. She would take care of all five felines at her home. Her patient agreed, and finally got the care she needed.

“It takes patience, persistence, building trust and love,” Bales said. “Someone might just take you up on it.”