HISTOPLASMOSIS.pptx

Histoplasmosis

1. HISTOPLASMOSIS Pr esented By Vigneshwari.D 1 ST M.Sc Microbiology Sacred Heart College( Autonomos ) Tirupattur .

2. HISTOPLASMOSIS Histoplasmosis is an infection caused by a fungus called Histoplasma Capsulatum . The fungus lives in the environment, particularly in soil that contains large amounts of bird or bat droppings.

3. It is also known as....  Cave disease, Darling's disease, Ohio valley disease, Reticuloendotheliosis , Spelunker's lung and Caver's disease. .

4. General Characteristics Dimorphic fungus - Sexual multi-cellular saprophytic mycelia - Asexual single-celled parasitic yeast Mycelial form most commonly found in the environment. Heteroth allic species. Tightly Coiled septate hyphae Smooth,hyline,spherical Ascospores Globose cleistothecia Pear – shaped asci

5. Condia germinate via non/polar budding. Yeast form is the infectious agent in humans. Yeast cells have white,thin-walled,oval bodies. Form sexual macro – and microconidia - Also borne by hyphae in the mycelial form.

6. Histoplasmosis - Types Two major forms of histoplasmosis 1)Pulmonary histoplasmosis 2)Disseminated histoplasmosis

7. Pulmonary histoplasmosis Pulmonary histoplasmosis occurs when microconidia or mycelial fragments are inhaled. Form lesions in the hilar or mediastainal nodes.

8. Pulmonary histoplasmosis types 1.Asymptomatic pulmonary histoplasmosis 2.Acute pulmonary histoplasmosis 3.Mediastinal granuloma 4.Fibrosing mediastinitis 5.Chronic cavity pulmonary histoplasmosis

9. pathogenesis

10. Clinical Manifestations Most people who are exposed to the fungus  Histoplasma  never have symptoms. Fever Cough Fatigue (extreme tiredness) Chills Headache Chest pain Body aches

11. Symptoms of histoplasmosis may appear between 3 and 17 days after a person breathes in the fungal spores. In some people, usually those who have weakened immune systems, histoplasmosis can develop into a long-term lung infection, or it can spread from the lungs to other parts of the body, such as the central nervous system (the brain and spinal cord). 

12. PREVENTION Avoid exposure.  Avoid projects and activities that might expose you to the fungus, such as cave exploring and raising birds, such as pigeons or chickens. Spray contaminated surfaces.  Before you dig soil or work in an area that could harbor the fungus that causes histoplasmosis , soak it with water. This can help prevent spores from being released into the air. Spraying chicken coops and barns before cleaning them also can reduce your risk.

13. Laboratory diagnosis 1.Specimens Sputum Bone- marrow aspirate Peripheral blood Scrapings from dermal or mucosal ulcers Biopsy of lymph nodes and other organs

14. 2.Direct examination Smears of sputum or pus are stained with giemsa or wright stains. In tissues,the yeast phase occurs within phagocytic cells The yeast appers as an oval,budding cell measuring 2-4 µm while in african histoplasmosis,much larger yeast –like cells(7-15µm) are seen.

15. H.capsulatum

16. 3.Culture SDA or brain heart infusion (BHI) agar with cyloheximide and chloramphenicol are inoculated. The yeast phase is formed in culture at 37°C . White cottony mycelial growth containing large (8-20 µm) thick walled ,spherical spores with tubercles or finger like projections appears at 25°C.

17. 3.Serological tests Latex aggultination precipitation and complement fixation tests become positive two weeks after infection. Increase in titre of antibody indicates a progressive disease.

18. 4.Histoplasmin skin test Delayed hypersensitivity test. The test is similar to tuberculin test but antigen used is histoplasmin . Histoplasmin is a culture filtrate antigen of mycelial phase of H.capsulatum . A positive ‘ histoplasmin skin test’ indicates past or present infection,but does not differentiate active and past infections.

19. Diagnosing histoplasmosis can be complicated, depending on what parts of your body are affected. While testing might not be necessary for mild cases of histoplasmosis , it can be crucial in treating life-threatening cases.

20. Treatment Itraconazole is one type of antifungal medication that's commonly used to treat histoplasmosis . Depending on the severity of the infection and the person's immune status, the course of treatment can range from 3 months to 1 year. Many people will need antifungal treatment for histoplasmosis .

21. Severe infections or disseminated cases of histoplasmosis require treatment with  antifungal medications . Itraconazole fluconazole amphotericin B drug of choice for severe disease are antifungal drugs that treat histoplasmosis .