US States Grapple with Rising Shigellosis Cases Amid Antibiotic Resistance Concerns

A growing number of U.S. states are reporting an increase in cases of shigellosis, a bacterial infection characterized by severe diarrhea, often bloody, alongside stomach cramps, fever, and vomiting. Provisional data from the Centers for Disease Control and Prevention (CDC) shows that 27 states and territories recorded higher case numbers in the week leading up to October 3 compared to the same period last year. These upticks were predominantly observed in the Northeast, Midwest, and West.

Nationwide, 14,291 cases have been recorded this year, a figure only slightly lower than the total at this point last year. This rise is occurring alongside significant concern over a 'superbug' strain of shigella that exhibits increased resistance to standard antibiotic treatments and can cause more severe symptoms.

While shigellosis is typically transmitted through contaminated food or surfaces, it is increasingly being spread sexually, particularly through anal sex, due to contact with fecal matter. The CDC notes that infections can be fatal in rare instances due to severe dehydration or malnutrition.

California has reported the highest number of shigellosis cases this year with 2,970 infections, though this represents a 10% decrease from the previous year. New York City follows with 1,276 cases, a 5% increase, and Florida has recorded 1,070 cases, up 14%.

Among states with the most significant increases, Wyoming saw its cases double from seven to 14. Vermont experienced a 90% surge, from nine to 17 cases, and New Mexico reported a 75% jump, from 119 to 207 cases. Conversely, South Dakota experienced the sharpest decline, with cases dropping 90% from 64 to five. Montana saw a 83% decrease, and Alaska a 64% decrease.

The states and territories that registered an increase in infections compared to last year include Arizona, Florida, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Nebraska, Nevada, New Hampshire, New Mexico, New York, New York City, North Carolina, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, Tennessee, Vermont, Virginia, West Virginia, and Wyoming.

Historically, shigellosis infections are most common in children under five due to less developed immune systems. However, current data indicate a growing incidence among gay and bisexual men, international travelers, and individuals experiencing homelessness.

Estimates suggest that approximately 450,000 Americans are diagnosed with shigellosis annually, with about 6,000 hospitalizations and 40 deaths. A CDC report released in April highlighted the alarming spread of the extensively drug-resistant (XDR) strain of shigella. Analysis of nearly 17,000 cases showed the proportion caused by this XDR strain rose from 0% between 2011-2015 to 8.5% in 2023.

More than a third of patients infected with the drug-resistant strain required hospitalization, although no deaths were reported in this subgroup. Researchers warned that the increasing prevalence of this strain could transform shigellosis from a typically self-limiting illness into a significant public health threat.

Of the patients infected with the superbug strain, 86% were men, and 47% were also co-infected with HIV. While data on sexual orientation were not collected in that specific analysis, previous studies have indicated a higher prevalence of the disease among gay and bisexual men. Dr. Naeemah Logan, an epidemiologist involved in the research, described the pattern of XDR Shigella strains among vulnerable populations as "very concerning," noting that this is part of a broader global trend.