Campylobacter: The Most Common Foodborne Illness Most People Have Never Heard Of

Most people have heard of Salmonella. Nearly everyone has heard of E. coli. But Campylobacter infects more Americans every year than both of them, and most people wouldn’t recognize the name.

The CDC estimates 1.5 million Campylobacter infections in the US annually. That translates to roughly 6,000 hospitalizations and 76 deaths. And those numbers likely undercount the true burden — most cases resolve on their own, so many people never get tested or diagnosed.

What Campylobacter Is

Campylobacter is a genus of bacteria. The species responsible for almost all human foodborne illness is Campylobacter jejuni. Under a microscope, it looks like a tiny corkscrew or spiral. It’s a gram-negative bacterium that needs very little oxygen to thrive (it’s described as “microaerophilic”) and grows best at body temperature — 98.6°F.

Unlike Salmonella or Staph aureus, Campylobacter is fragile outside a living host. It doesn’t multiply in food at refrigerator temperatures. It dies quickly when dried out. It can’t survive freezing for long. Yet it still causes the most bacterial foodborne illness in the country, which tells you something about how heavily it colonizes its primary reservoir: poultry.

Where It Comes From

Raw and undercooked poultry accounts for roughly 80% of Campylobacter cases. The bacteria live in the intestinal tracts of chickens, turkeys, and other birds without making them sick. Contamination happens during slaughter and processing when intestinal contents contact the carcass. USDA sampling consistently finds Campylobacter on a significant percentage of retail chicken.

The other sources are smaller but real. Unpasteurized dairy milk has been linked to outbreaks. Contaminated water (from drinking untreated well or surface water) causes both individual cases and community outbreaks. And dogs and cats — particularly young animals like puppies and kittens — frequently carry Campylobacter and can transmit it through contact with their feces or via poor hand hygiene after handling them.

Symptoms and Timing

The incubation period — the time from eating contaminated food to feeling sick — is 2 to 5 days. That’s longer than Salmonella’s range of 6 hours to 6 days on average. By the time symptoms appear, most people can’t trace them back to the meal that caused them.

Symptoms include:

• Diarrhea, often watery, sometimes bloody
• Stomach cramping and pain
• Fever (often the first sign)
• Nausea and occasional vomiting

The illness typically lasts 2 to 10 days. Bloody diarrhea happens in a substantial portion of cases. When it does, it can look alarming enough that people assume something worse is happening.

Healthy adults usually recover without treatment. Some cases warrant antibiotics, particularly for people with prolonged symptoms or those in high-risk groups. Azithromycin is the first-line antibiotic, though resistance is growing in some strains.

The Guillain-Barré Connection

This is the complication that sets Campylobacter apart from most foodborne pathogens.

Guillain-Barré syndrome (GBS) is a rare autoimmune disorder. The immune system, after fighting off an infection, mistakenly turns on the peripheral nervous system. It attacks the myelin sheath covering nerve fibers, disrupting the nerve signals that control muscle movement.

Campylobacter is the leading known infectious trigger of GBS. About 1 in 1,000 Campylobacter infections leads to the syndrome. That sounds rare. Across 1.5 million annual infections, it produces roughly 1,500 GBS cases per year linked to Campylobacter alone.

GBS starts with weakness or tingling in the legs and can progress upward. In severe cases, it causes temporary full-body paralysis, including the muscles needed for breathing. Most patients need hospitalization. Many require mechanical ventilation. Recovery happens over months to years in most cases, and some patients have long-term disability.

The link between Campylobacter and GBS was confirmed by multiple studies. Certain Campylobacter strains carry surface proteins that closely resemble nerve cell proteins. The antibodies that fight the bacteria can cross-react with nerve tissue — a phenomenon called molecular mimicry.

Prevention Is Simple

The prevention here is the same as for Salmonella, because the primary source is the same: raw poultry.

Cook all poultry to 165°F, measured at the thickest part of the meat with an actual thermometer. Color is unreliable. The pink chicken myth explains why visual cues fail.

Don’t wash raw chicken. Rinsing spreads Campylobacter-containing water droplets to the sink, nearby counter surfaces, and anything else in splash range. The washing raw chicken debate covers the research on how far contamination travels and why washing makes things worse. Cooking to 165°F kills the bacteria without spreading it.

Treat every raw poultry surface as contaminated. That means separate cutting boards, washing hands with soap for at least 20 seconds after handling raw chicken, and washing everything that touched the raw meat before it contacts anything else.

For dairy: drink pasteurized milk. The pasteurization kill step (at minimum 161°F for 15 seconds in HTST pasteurization) eliminates Campylobacter reliably. Unpasteurized (“raw”) milk is one of the higher-risk foods for multiple bacterial pathogens, including this one.

Campylobacter doesn’t get the press coverage of Salmonella or E. coli O157:H7, partly because it’s less dramatic and rarely causes large, traceable outbreaks from a single food source. Most cases are sporadic — one person, one meal. But the case count tells the real story. It’s the most common bacterial foodborne illness in the country, and it’s almost entirely preventable with proper cooking and kitchen hygiene.

See the safe internal temperatures guide for the full temperature table, and food safety fundamentals for a complete overview of the practices that stop all bacterial pathogens including this one.