Parasitic infections of Respiratory Tract.pptx

Parasitic infections of Respiratory tract Microbiology

1. PARASITIC INFECTIONS OF RESPIRATORY TRACT C1 BATCH

2. Introduction Respiratory tract infections (RTI) can be produced by variety of parasitic agents Paragonimus westermani: primary pathogen of lungs Parasites causing hypersensitivity in lungs : filarial nematodes causing tropical pulmonary eosinophilia Parasites that pass through lungs during their life cycle : Ascaris , Hookworm , Strongyloides etc Parasites that infect other organs , rarely infect lungs : E.histolytica , Toxoplasma , Balantidium coli etc

3. PARAGONIMIASIS Caused by a trematode ->paragonimus westermani ( oriental lung fluke ) Life cycle :- Definitive host - human Intermediate hosts - snail ( first ) Crab or crayfish ( second ) Infective form : Metacercaria larvae Diagnostic form : egg

4. Life cycle

5. Clinical features Pulmonary paragonimiasis or endemic hemoptysis :- ~eosinophilic granulomatous inflammation in lungs ~presented as productive cough with brownish blood tinged sputum with an offensive fishy odour Extrapulmonary paragonimiasis :- ~ cutaneous and cerebral forms are seen

6. Lab diagnosis Sputum microscopy : oval , golden brown operculated eggs ELISA : for antigen or antibody detection

7. Treatment and prevention Praziquantel is the drug of choice Prevention:- sanitary disposal of sputum Control of snails Treatment of cases Health education

8. TROPICAL PULMONARY EOSINOPHILIA (TPE) Also known as occult filariasis or weingarten’s syndrome Develops in some infected individuals with Wuchereria bancrofti and Brugia malayi Pathogenesis :- It is a hypersensitivity reaction to microfilaria antigen Microfilariae are rapidly cleared from the bloodstream and filtered , lodged and destroyed in lungs initiating an allergic response

9. Clinical features nocturnal paroxysmal cough Wheezing Weight loss Low grade fever Microfilaria can entrap in other organs like spleen,liver and lymph node leading to hepatosplenomegaly and lymphadenopathy ->Meyers kouwenaar syndrome

10. Diagnosis and treatment Diagnosis :- Blood eosinophilia Diffuse infiltration in chest x ray Elevated serum IgE levels Treatment :- diethylcarbamazine

11. MIGRATORY STAGE OF INTESTINAL NEMATODES Ascariasis

12. Clinical features Migrating larvae in lungs induce an immune mediated hypersensitivity response Common symptoms : non productive cough, chest discomfort and fever Loeffler’s syndrome : in severe cases, patients develop dyspnea and a transient patchy infiltrate seen on chest x ray along with peripheral eosinophilia

13. Diagnosis Eosinophilia is prominent during early lung stage but disappears later Charcot Leyden crystals in sputum and stool Larvae can be found in gastric aspirates or sputum

14. MIGRATORY STAGE OF INTESTINAL NEMATODES (2) Hookworm infection Migrating larvae through lungs cause transient pneumonitis , asthma and bronchitis (3) Strongyloidiasis Pulmonary symptoms are uncommon compared to ascaris and hookworm Occurs only secondary to COPD

15. RARE PARASITIC PULMONARY INFECTIONS There are number of parasitic infections in which pulmonary involvement may occur rarely , secondary to the primary organ they infect Pulmonary amoebiasis : caused by E.histolytica . Primary sites involved are intestine and liver Pulmonary toxoplasmosis : caused by toxoplasma gondii ; mainly causes encephalitis and congenital infection Pulmonary balantidiasis : caused by Balantidium coli , primarily infects intestine Respiratory cryptosporidiosis : occur occasionally in HIV infected individuals Pulmonary hydatidosis : caused by Echinococcus granulosus , primarily infects liver