1. VIRAL & FUNGAL INFECTIONS OF GIT Assist Prof Dr. Syed Yousaf Kazmi

2. OBJECTIVES Major Viruses & Fungi that cause gastrointestinal diseases, their epidemiology, etiology, pathogenesis Mechanism of transmission; Enlist clinical conditions Laboratory diagnosis of these infections

3. VIRAL INFECTIONS OF GIT Viral Gastroenteritis – Rotavirus – Astrovirus – Adenovirus – Calicivirus Viral Hepatitis – Hepatitis A – Hepatitis E Electron microscopy of Rotavirus

4. ROTA VIRUS Rotaviruses-major cause of diarrhea in infants Adult also infected Non-enveloped RNA Virus Various serotypes A, B, C Rotaviruses infect cells in the villi of the small intestine (gastric and colonic mucosa are spared Multiply in the cytoplasm of enterocytes Damaged cells slough into the lumen Large quantities of virus in stool Viral excretion usually lasts 2–12 days in otherwise healthy patients

5. ROTA VIRUS-EPIDEMIOLOGY & CLINICAL PRESENTATION Single most imp worldwide cause of gastroenteritis in young children 50% of Acute GE of hospitalized children throughout the world Between ages 6 months and 2 yrs Incubation period of 1–3 days Watery diarrhea, fever, abdominal pain, vomiting, leading to dehydration Severe loss of electrolytes & fluids may be fatal Transmission by the fecal–oral route Local immunity e.g. secretory IgA hospitalization of infants and young children with severe diarrhea

6. OTHER VIRUS CAUSING GASTROENTERITIS VIRUSEPIDEMIOLOGY IMP CAUSE OF HOSP Enteric adenovirus Second most important viral agent of endemic diarrheal illness of infants and young children worldwide Yes Caliciviruses (Norovirus) Important cause of outbreaks of vomiting and diarrheal illness in older children and adults in families, communities, and institutions; frequently associated with ingestion of food No AstrovirusesSporadic cases and occasional outbreaks of diarrheal illness in infants, young children, and the elderly No

7. LABORATORY DIAGNOSIS Electron microscopy (EM) Immune electron microscopy (IEM) Detection of viral antigen by ELISA more sensitive than IEM PCR of viral genome most sensitive (Rotavirus) Serology- IgG and IgM antibodies against viral antigens

8. VIRAL HEPATITIS Hepatitis A virus & Hepatitis E virus Both transmitted-fecal oral route (water, food) Non enveloped virus HAV stable to treatment with 20% ether, acid (pH 1.0 for 2 hrs), heat (60°C for 1 hr) Virus is destroyed by autoclaving (121°C for 20 minutes), by boiling in water for 5 minutes HEV- usually epidemic form

9. VIRAL HEPATITIS-PATHOGENESIS & EPIDEMIOLOGY Acute hepatitis HAV inf usually asymptomatic, mild fatigue, vomiting, nausea, mild jaundice in children In adult signs & symptoms of icteric, fever HAV no carrier state, mortality <1% HEV –acute hepatitis in epidemics No carrier state HEV-Association of high mortality in pregnant ♀ (30- 40%)

10. VIRAL HEPATITIS- LAB DIAGNOSIS LFTs-deranged IgG & IgM antibodies in serum by ELISA (HAV & HEV) Liver biopsy for H/P Viral genome by PCR Electron microscopy

11. FUNGAL INFECTION OF GIT Pseudomembranous Candidiasis of upper & lower GIT – Oral thrush – Candida esophagitis in HIV – Colitis Invasive Aspergillosis (rare) Oral thrush in leukemic patient

12. FUNGAL INFECTION OF GIT Opportunistic fungal infection Candida is normal flora of GIT Cell mediated immunity impairment Overgrowth of Candida Associated with use of broad spectrum antimicrobials

13. FUNGAL INFECTION –LAB DIAGNOSIS Gram Stain of scrapping Culture on Sabouraud agar Biochemical identification Gram stain of Candida albicans Candida on Sabouraud Agar

14. MCQ A 57-years-old patient who is suffering from Hodgkins Lymphoma presents with pain & swelling of tongue. On examination, white curdy patches were noted on tongue. Gram stain of the scrapping revealed Gram positive budding structure. Which of the following cell structure will be missing in this organism? a.Cell membrane b.Mitochondria c.Nuclear membrane d.Cell wall peptidoglycan e.Ribosome

15. MCQ A 32-years-young pregnant lady developed yellow discoloration of sclerae, nausea, vomiting and abdominal pain. Patient died on third day of hospital admission. If the etiological agent has fecal oral route of transmission, which of the following agent is most likely cause of her illness? a.HAV b.HBV c.HCV d.HDV e.HEV

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