Microspora, Pneumocystis & Blastocystis hominis

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1 PARA Microspora, Pneumocystis & Blastocystis hominis Nimit Morakote, Ph.D.

2 Microspora A group of organisms: small single-celled, obligate intracellular parasites belonging to Phylum Microspora Early- eukaryotic protozoa Recently- classified as primitive fungi >2,000 species infecting vertebrates and invertebrates 14 species infecting human- truly opportunistic

3 Some microspora infecting human Encephalitozoon cuniculi Encephalitozoon hellem Encephalitozoon (Septata) intestinalis Enterocytozoon bieneusi Trachipleistophora hominis Trachipleistophora anthropopthera. Pleistophora ronneafiei Vittaforma (Nosema) corneae Nosema ocularum Brachiola vesicularum Brachiola (Nosema) algerae Brachiola (Nosema) connori Microsporidium (Nosema) africanum Microsporidium (Nosema) ceylonensis Trachipleistophora anthropopthera Trachipleistophora hominis

4 Morphology Spores size 1-40 µm Species infecting human are relatively small, µm µm Inner spore wall is chitinous Special organelles- coiled polar tube or filament- for infecting host cell 4-30 coils, used for species differentiation

5 Evolution from photosynthetic algae Lack mitochondria, peroxisome, Golgi apparatus Merogony and sporogony in cytoplasm, mostly without parasitophorous vacuole

6 Life cycle: 2 alternatives 2 sec sporont meront spore TRENDS in Parasitology Vol.20 No.6 June 2004

7 Disease Truly opportunistic, CD4 <50/µL Small intestine, eyes, muscle, respiratory tract, urinary tract, biliary tract, skin E. bieneusi- the small intestine Persistent diarrhea, abdominal pain, weight loss E. intestinalis- Persistent diarrhea Extraintestinal dissemination: sinusitis, keratoconjunctivitis, encephalitis, tracheobronchitis, interstitial nephritis, hepatitis, or myositis

8 Animal host E. bienneusi: in pigs, monkeys E. intestinalis: farm animals Human host Both immunocompetent and immune-deficient Travelers, children, organ transplant recipients, cancer patients, diabetics, and the elderly May be responsible for diarrhea of unknown etiology World wide distribution including Thailand

9 Olga Matos, Maria Luisa Lobo, and Lihua Xiao. Epidemiology of Enterocytozoon bieneusi Infection in Humans. Journal of Parasitology Research. Volume 2012 (2012), Article ID , 19 pages

10 Transmission Fecal- oral, in waste water Outbreak among hotel visitor due to contaminated cucumber in Sweden Diagnosis Stool smear and stained Spores Modified trichrome- red spore with belt Treatment: albendazole topical fumagillin for ocular infection Modified trichrome stain

11 Pneumocystis jirovecii First identified in 1909 in rat lung, named Pneumocystis carinii of uncertain taxonomy Cause infantile pneumonia Recently classified as atypical fungus in Phylum Ascomycota, Family Pneumocystidaceae Renamed Pneumocystis jirovecii to be distinctive from rat s species (some phenotypical difference)

12 Putative life cycle of Pneumocystis. Precyst stages (early, intermediate, late) 1-4 µm, adhere to alveolar epithelium Beck J M, and Cushion M T Eukaryotic Cell 2009;8: Mature cyst or ascus (8-10 µm) with 8 intracystic bodies (spores)

13 Disease Pneumocystis pneumonia, interstitial plasma cell pneumonia Premature infants AIDS Organ transplant subjects Malignancies Steroid treatment, long term Fever, cough, dyspnea Trimethoprimsulfamethoxazole (TMP-SMX) Chemoprophylaxis when CD4 < 200 cells/microliter Histogical picture: Alveolar spaces filled with eosinophilic, vacuolated or foamy exudate containing 4-5um cysts

14 Epidemiology Niches uncertain, airborne transmission Human acquires infection during infancy, asymptomatic, latent infection Reactivated when immunocompromised or primary infection is controversial

15 Diagnosis Specimen from lungs Induced sputum Bronchoalveolar lavage (BAL) Stain for cysts Methenamine silver nitrate Toluidine Blue O Stain for trophics forms and intracystic bodies Giemsa stain Beck J M, and Cushion M T Eukaryotic Cell 2009;8:

16 Blastocystis hominis Recently placed into stramenopiles, a complex and heterogeneous evolutionary assemblage of heterotrophic and photosynthetic protozoa Inhabit large intestine. Uncertain pathogenicity, frequently found in diarrheic stool.

17 4 major forms Vacuolar Vacuolar, µm Nuclei and mitochondria-like structure at rim Granular, µm Amoeboid, µm Cyst, 3-10 µm Granular Cyst amoeboid Tan KSW. Clin Microb Rev. Oct 2008; 21(4):

18 7 Subtypes Man infected with cysts of any of 7 subtype Lab Diagnosis: Vacuolar form in faeces Tan KSW. Clin Microb Rev. Oct 2008; 21(4):

19 Worldwide, may exceed 5% in general population, and up to 30-60% in developing countries Claim to associate with gastrointestinal disorder, urticaria. nonspecific gastrointestinal symptoms- diarrhoea, abdominal pain, flatulence, nausea, vomiting, constipation, weight loss or fatigue irritable bowel syndrome (IBS) Acute or chronic urticaria First line therapy= Metronidazole Second choice = cotrimoxazole, ornidazole, nitazoxanide, paromomycin, chloroquine, trimethoprimsulfamethoxazole, etc.

20 Further readings Mathis A, et al. Zoonotic Potential of the Microsporidia. Clin Microbiol Rev 2005; 18: Catherinot E, et al. Pneumocystis jirovecii Pneumonia. Infect Dis Clin N Am 2010; 24: Wawrzyniak, et al. Blastocystis, an unrecognized parasite: an overview of pathogenesis and diagnosis. Ther Adv Infect Dis. Oct 2013; 1(5):