ListeriosisListeriosis, a serious infection caused

by eating food contaminated with the bacterium Listeria monocytogenes, has recently been recognized as an important public health problem in the United States.

The disease affects primarily persons of advanced age, pregnant women, newborns, and adults with weakened immune systems. However, persons without these risk factors can also rarely be affected.

Risk for listeriosisPregnant woman Newborns Persons with weakened immune systemsPersons with cancer, diabetes, or kidney

diseasePersons with AIDS - They are almost 300

times more likely to get listeriosis than people with normal immune systems.

Persons who take glucocorticosteroid medications

The elderly

• Listeria monocytogenes is found in soil and water

Can be found in a variety of raw foods, such as uncooked meats and vegetables, as well as in processed foods that become contaminated after processing, such as soft cheeses and cold cuts at the deli counter.

Unpasteurized (raw) milk or foods made from unpasteurized milk may contain the bacterium.

Listeria is killed by pasteurization and cooking; however, in certain ready-to-eat foods such as hot dogs and deli meats, contamination may occur after cooking but before packaging.

Listeria monocytogenes(AGENT)

Infected ruminant animals

(reservoir)

Stool(portal of exit)

Ingestion of

contaminated foods (mode of

transmission)

Gastro intestinal

tract (Portal of

entry)

Human (host)

Signs and symptomsFever

Stiff neck

Diarrhea

Standard Diagnostic TestsClinical specimens from normally sterile sites

(blood, CSF, amniotic fluid) can be directly plated onto tryptic soy agar containing 5% sheep, horse, or rabbit blood.

When plated on LPM agar, Listeria colonies appear blue under oblique lighting while other bacteria appear yellowish or orange.

Chromogenic media can be used and many types are available; these can identify, but not differentiate between L monocytogenes and L ivanovii.

Samples for blood culture can be inoculated into conventional blood culture broth.

Clinical specimens obtained from nonsterile sites as well as food and environmental specimens should be enriched for Listeria species before being plated

Treatment Ampicillin is the preferred drug for

treatmentFor the penicillin-allergic

patient trimethoprim-sulfamethoxazole should be used.

Initial therapy for bacterial meningitis in adults older than age 50 should include either ampicillin or trimethoprim-sulfamethoxazole.

Chloramphenicol should not be used to treat Listeria infections because of its failure and relapse rates.

Prevention General recommendations:Thoroughly cook raw food

from animal sources, such as beef, pork, or poultry.

Wash raw vegetables thoroughly before eating.

Keep uncooked meats separate from vegetables and from cooked foods and ready-to-eat foods.

Avoid unpasteurized (raw) milk or foods made from unpasteurized milk.

Wash hands, knives, and cutting boards after handling uncooked foods.

Hymenolepis infectionThe dwarf tapeworm

or Hymenolepis nana and Hymenolepis diminuta is the most common tapeworm infection diagnosed in the in the United States and throughout the world.

Infection is diagnosed in children, in persons living in institutional settings, and in people who live in areas where sanitation and personal hygiene is inadequate.

Hymenolepis nana

and diminuta(agent)

Infected rats

(reservoir)

Stool (portal exit)

Ingesting fecally

contaminated foods

Gastrointestinal tract (portal of

entry)

Human (host)

Signs and symptomsAbdominal

pain

Anorexia

Irritability

Itching around the anus

Diagnostic test Examination of

the stool for eggs and parasites confirms the diagnosis. The eggs and proglottids of H. nana are smaller than H. diminuta. 

Treatment Praziquantel as a single dose

(25 mg/kg) is the current treatment of choice for hymenolepiasis and has an efficacy of 96%.

Single dose albendazole (400 mg) is also very efficacious (>95%). Niclosamide has also been used.

A three-day course of nitazoxanide is 75–93% efficacious

PreventionGood hygienePublic health

and sanitation programs

Elimination of rats help prevent the spread of hymenolepiasis

Toxoplasmosis Toxoplasmosis is caused by

the protozoan parasite Toxoplasma gondii. In the United States it is estimated that 22.5% of the population 12 years and older have been infected with Toxoplasma.

In various places throughout the world, it has been shown that up to 95% of some populations have been infected with Toxoplasma.

Infection is often highest in areas of the world that have hot, humid climates and lower altitudes.

Toxoplasma

gondii(agent)

Infected cats

(reservoir)

Stool (portal of exit)

Ingestion of

contaminated cat feces(direct

contact)

Gastrointestinal tract

(portal of entry)

human

Signs and symptomsAcute

toxoplasmosisInfluenza Swollen lymph

nodesMuscle ache

Latent toxoplasmosisMost patients who become infected

with Toxoplasma gondii and develop toxoplasmosis do not know it. In most immunocompetent patients, the infection enters a latent phase, during which only bradyzoites are present, forming cysts in nervous and muscle tissue.

Most infants who are infected while in the womb have no symptoms at birth but may develop symptoms later in life.

Diagnostic testToxoplasmosis can be

detected with immunostaining .

 Lymph nodes affected by toxoplasma have characteristic changes, including poorly demarcated reactive clusters of monocytoid B cells and scattered epithelioid histiocytes

Treatment For acute toxoplasmosisPyrimethamine— an antimalarial medication. Sulfadiazine— an antibiotic used in combination

with pyrimethamine to treat toxoplasmosis.Clindamycin— an antibiotic used most often for

people with HIV/AIDS.Cotrimoxazole — combitation of Pyrimethamine

and Sulfadiazine in one tablet another option for people with problems like thrombocytopenia.

Spiramycin — an antibiotic used most often for pregnant women to prevent the infection of their child.

Prevention and controlCook food to safe temperatures. A food

thermometer should be used to measure the internal temperature of cooked meat. Do not sample meat until it is cooked. Beef, lamb, and veal roasts and steaks should be cooked to at least 145°F throughout.

Pork, ground meat, and wild game should be cooked to 160°F.

Whole poultry should be cooked to 180°F in the thigh.

Peel or wash fruits and vegetables thoroughly before eating.

Photo courtesy of USDA.Wash cutting boards, dishes,

counters, utensils, and hands with hot soapy water after contact with raw meat, poultry, seafood, or unwashed fruits or vegetables.

Freeze meat for several days before cooking to greatly reduce chance of infection.

Avoid drinking untreated drinking water, particularly when travelling in less developed countries.

Wear gloves when gardening and during any contact with soil or sand because it might be contaminated with cat feces that contain Toxoplasma. Wash hands thoroughly after gardening or contact with soil or sand.

Feed cats only canned or dried commercial food or well-cooked table food, not raw or undercooked meats.

Change the litter box daily If you own a cat. The Toxoplasmaparasite does not become infectious until 1 to 5 days after it is shed in a cat's feces. If you are pregnant or immunocompromised:

(CDC Photo)Avoid changing cat litter if possible. If no one else

can perform the task, wear disposable gloves and wash your hands thoroughly with soap and water afterwards.

Keep cats indoors.Do not adopt or handle stray cats, especially kittens.

Do not get a new cat while you are pregnant.

Reported by Cacho, Patrick Maru

Thank you!