Campylobacter jejuni is a bacterium recognized as a frequent cause of foodborne illness globally. Understanding its characteristics, how it spreads, and the effects it can have on human health is important for public health.
Understanding Campylobacter jejuni
Campylobacter jejuni is a type of bacteria characterized by its spiral or curved rod shape. It is a Gram-negative bacterium. This bacterium is microaerophilic, thriving in environments with low oxygen levels, typically between 5% and 10% oxygen, and grows optimally at temperatures around 37 to 42 °C.
C. jejuni is a leading cause of bacterial foodborne illness, known as campylobacteriosis. It is widespread, affecting people of all ages, though it is more prevalent in developing countries. In the United States, active surveillance estimates approximately 20 cases are diagnosed per 100,000 people annually, with the Centers for Disease Control and Prevention (CDC) estimating a total of 1.5 million infections each year, many of which are undiagnosed or unreported.
How Infection Occurs
Infection with Campylobacter jejuni primarily occurs through the ingestion of contaminated food or water. Raw or undercooked poultry, such as chicken, turkey, duck, and goose, is a particularly common source, with studies showing high contamination rates in retail chicken. Consuming unpasteurized milk is another significant route of transmission, as bacteria can enter the milk from contaminated udders or manure.
Contaminated water, including untreated drinking water from wells or streams, can also lead to infection. Contact with infected animals, including livestock like cattle, pigs, and sheep, as well as pets such as cats and dogs, can transmit the bacteria. The bacteria are often found in animal feces.
Cross-contamination in the kitchen is a significant pathway for C. jejuni spread. This happens when bacteria from raw poultry or other contaminated foods are transferred to ready-to-eat foods or surfaces. Using the same cutting board or utensils for raw meat and then for vegetables or other foods without proper cleaning can facilitate this transfer. Inadequate handwashing after handling raw meat also contributes to the spread of the bacteria.
Symptoms and Diagnosis
Symptoms of Campylobacter infection, known as campylobacteriosis, typically appear within 2 to 5 days after exposure to the bacteria, though the incubation period can range from 1 to 11 days. The most common clinical symptoms include diarrhea, which can often be bloody, along with abdominal cramps, fever, nausea, and vomiting.
The illness usually lasts for about 3 to 6 days, with most people recovering within a week. In some cases, symptoms can be more severe or prolonged. Dehydration is a possible concern, especially in young children, due to fluid loss from diarrhea and vomiting.
Diagnosis of Campylobacter jejuni infection is typically confirmed by identifying the bacteria in a stool (feces) sample. Laboratory tests detect Campylobacter organisms. In some instances, the bacteria may also be found in body tissue or fluid samples.
Treatment and Prevention
Treatment for Campylobacter jejuni infection primarily focuses on supportive care, as most healthy individuals recover without specific medical intervention. The main goal is to prevent dehydration by ensuring adequate fluid intake, such as clear liquids or oral rehydration solutions. Rest is also recommended to aid recovery.
Antibiotics are generally not prescribed for mild cases of campylobacteriosis. However, they may be considered for individuals with severe illness, those who are immunocompromised (such as people with cancer, HIV/AIDS, or organ transplants), or very young children and the elderly. When antibiotics are indicated, macrolide antibiotics like azithromycin or erythromycin are often used, and they can help shorten the duration of symptoms if administered early in the illness. It is important to note that some strains of Campylobacter have developed resistance to commonly used antibiotics, which can make infections harder to treat.
Preventing Campylobacter infection involves several practical food safety and hygiene practices. Thoroughly cooking poultry and other meats to their safe internal temperatures is important, as heat effectively kills Campylobacter species. Avoiding raw or unpasteurized dairy products, such as unpasteurized milk, is also advised. Ensuring drinking water is from a safe, treated source is also important.
Good hygiene practices are also important, including frequent and thorough handwashing with soap and water. This is particularly important after handling raw meat, after contact with animals or their feces, and before preparing or eating food. Preventing cross-contamination in the kitchen by using separate cutting boards and utensils for raw meats and ready-to-eat foods, and properly cleaning surfaces that have come into contact with raw meat, can further reduce the risk of transmission.
Potential Complications
While most Campylobacter jejuni infections are self-limiting, some individuals may experience less common but serious complications after the acute illness. One such complication is Guillain-Barré Syndrome (GBS), a rare autoimmune disorder affecting the peripheral nervous system.
GBS can lead to progressive muscle weakness and, in some cases, paralysis. Approximately 1 in every 1,000 reported Campylobacter illnesses may lead to GBS, and it is estimated that up to 40% of GBS cases in the United States are triggered by Campylobacter infection. Symptoms of GBS typically appear 1 to 3 weeks after the Campylobacter infection.
Another potential complication is reactive arthritis, which involves joint inflammation and can occur weeks after the initial infection. Reactive arthritis is often oligoarticular and asymmetrical, commonly affecting the knees. While symptoms generally last up to 21 days, most patients recover within six months.