Pneumocystis jiroveci, Microsporidia, etc Flashcards
Pneumocystis (carinii) jiroveci General Biology
Classified as a Fungus but missing fungal components in PM. Two stages: trophozoites and cysts in lungs. transmitted in air.
Active infection of Pneumocystis (carinii) jiroveci
degenerates alveolar epithelium and fills spaces with cysts, debris, plasma cells. Causes foamy apperance in lungs, thickening of septa. eventually causes tachypnea and dyspnea and non-productive cough, fever, rales
Diagnosis of Pneumocystis (carinii) jiroveci
bilateral diffuse interstitial and alveolar infiltrate evenly invading ALL portions of the lung X-ray. Bronchoalveloar lavage via methenamine silver.
Pneumocystis (carinii) jiroveci Epidemiology
occurs in immunocompromised patients, including those with AIDS, malnourished or premature babies. AIDS patients given prophylactic treatment reduces number of cases
Microsporidia general characteristics
7 genera and 13 species have been found in humans
Spore has an extrusion apparatus consisting of polar tubule coils that dominates the spore contents. After the spore is ingested, the everted coiled tube penetrates host cells and injects sport contents into the cell cytoplasm. The parasite then divides and spread to other tissues or to the environment
Clincal Presentation in AIDS patients
GI infections causes chronic diarrhea wasting, malabsorption. corneal infections lead to conjunctival irritation, photophobia, foreign body sensation. Modes of transmission not known
Epi and Diagnosis of Microsporidia
electron/light level microscopy with special stains. found in Aids patients
Toxoplasma gondii General Characteristics
Obligate intracellular parasite that infects all mammals and birds
Infects all cells EXCEPT erythrocytes
Life Cycle of Toxoplasma gondii
sexual reproduction in intestine of cats ooyctes released in feces. Parasites invaded macrophages and replicated there
Chronic Infections of Toxoplasma gondii
Develop in the brain and muscle. viable for life of the host where they can rupture or infected other hosts if eaten.
Congenital transmission of Toxoplasma gondii
most infections during pregnancy particuarly in the third trimester. Most disease occurs in the first trimester. Can transfer to the fetus.
Heart transplant recipients Transmission of Toxoplasma gondii
Serelogical negative patient receives a heart from seropositive donor. serious disease can occur and prophylactic treatment.
Congenital Infection of Toxoplasma gondii
May be abortion or stillbirth. If fetus survives, may be cerebral calcification, hydrocephalus or microcephaly . Retinochoroiditis can occur later in life.
AIDS Patient P Infection of Toxoplasma gondii
Half develop cerebral toxoplasmosis. Most commonly due to recrudescence of a latent infection. Can led to brain necrosis and death. Chorioretinitis Is not Common
Diagnosis of Toxoplasma gondii
Serology, CT and MRI for AIDS patient
Prognosis of Toxoplasma gondii
Treatment usually not needed unless it severe symptoms or active retinochoriditis. life long therapy for immunocompromised patients.
Cryptosporidium parvum General Biology
Sexual and asexual reproduction occurs in the intestinal tract of a single host: Oocysts released in the stool are ingested and then sporozoites exit and attach to microvilli of small intestine epithelial cells. After a few cycles of asexual reproduction, gametes form which fuse to yield an oocyst. Oocysts are immediately infective
Normal Patients Infection of Cryptosporidium parvum
Watery, explosive and perfuse diarrhea with abdominal pain, anorexia, malaise, myalgia and weight loss. NO reinfection
Immunocompromised Patients Cryptosporidium parvum
Parasites are found throughout the GI tract and may be found in the lungs, liver and elsewhere
Severe diarrheal illness characterized by frequent, voluminous watery bowel movements persistent for months
Cryptosporidium parvum location
resides under the cell membrane of the microvilli
Transmission of Cryptosporidium parvum
Worldwide, Person-to-person transmission is the primary method of transmission, food or water contamination by human or animal feces is secondary
Cryptosporidium parvum Epidemiology
Found worldwide, but more commonly in the tropics. Seroprevalence US: 25% and Tropical regions (e.g. Venezuela): 65%
Diagnosis of Cryptosporidium parvum
Acid-fast or fluorescent staining for oocysts in feces
Cyclospora cayetanensis
very similar to Cryptosporidium. Infection associated with fever, ab pain, and diarrhea. Water and some fruits (raspberries).
