• The Listeria monocytogenes bacteria can cause a largely food-borne disease called listeriosis, with symptoms that range from the relatively benign to the severe, and even fatal. Listeria poses a particular risk to pregnant women; they comprise 30 percent of all yearly cases, according to a 2006 study by the Center for Disease Research and Policy. Listeriosis can be asymptomatic until it has spread, but a few symptoms can often act as a tip-off, particularly if they present together.
  
  

Flu or Something Worse?

• Most commonly emerging in the woman's third trimester, the most widespread sign of listeriosis is flu-like symptoms, including congestion, muscle fatigue, back pain, fevers, general flu-like malaise and sinus headaches. In fact, the initial symptoms can be indistinguishable at the outset of the patient becoming symptomatic. Only later, when the patient's condition, and that of her fetus, have deteriorated can a more precise diagnosis be made. Report any sign of the flu to your pre-natal health practitioner, especially if the "flu" seems to last longer than normal.
  
  

Gastrointestinal Problems

• Because Listeria monocytogenes is acquired from contaminated foods, one of the primary symptoms of listeriosis is persistent gastrointestinal upset. This is actually a blessing in disguise, because this presentation of the disease looks much like more familiar types of food poisoning. The patient may vomit, experience dizziness and vertigo, diarrhea and extreme nausea. Unlike flu symptoms, gastrointestinal upset isn't always present in listeriosis-affected patients; however, if presenting alongside a case of influenza in a third-trimester pregnant woman, the combination of symptoms may be the key to getting an accurate diagnosis.
  
  

Fetal Distress: An External Tip-Off

• One of the greatest dangers of listeriosis is the threat that it poses to the developing fetus. Distress in a fetus can have many origins, and isn't necessarily a sign of listeriosis, but the disease triggers specific kinds of infections and complications, such as a premature delivery, fetal sepsis and, because listeriosis is communicable during a vaginal delivery, late-onset neonatal meningitis. Ironically, these symptoms presenting in her newborn child can all be signs that a woman who has just given birth has a listeriosis infection.