Clostridium difficile (C. difficile) is a Gram-positive, sporeforming bacterium usually spread by the fecal-oral route. It is non-invasive and produces toxins A and B that cause disease, ranging from asymptomatic carriage, to mild diarrhea, to colitis, or pseudomembranous colitis. CDI is defined as the acute onset of diarrhea with documented toxigenic C. difficile or its toxin and no other documented cause for diarrhea.
Infection
Symptoms and Diagnosis of Zika Virus Infection
Zika virus is spread to people through mosquito bites. The most common symptoms of Zika virus disease are fever, rash, joint pain, and conjunctivitis (red eyes). The illness is usually mild with symptoms lasting from several days to a week. Severe disease requiring hospitalization is uncommon.
Diagnostic Criteria for Chronic HBV Infection
Chronic HBV infection is a necroinflammatory disease of the liver caused by persistent infection with HBV, and can be categorized as hepatitis B e antigen (HBeAg) positive or negative. Inactive hepatitis B surface antigen (HBsAg) carriers have HBV infection of the liver without significant, ongoing necroinflammatory disease. HBV infection is resolved when there is no further virologic, biochemical, or histologic evidence of active viral infection or disease.
Typical Serologic Course of Hepatitis A Virus (HAV) Infection
Since both clinically and biochemically, acute hepatitis due to HAV cannot be distinguished from that due to the other hepatitis viruses, serologic tests are necessary for a virus-specific diagnosis.
Serologic Testing for the Diagnosis of Hepatitis B Virus (HBV) Infection
The antigens and antibodies associated with HBV infection include HBsAg (Australia antigen) and antibody to HBsAg (anti-HBs), hepatitis B core antigen (HBcAg) and antibody to HBcAg (anti-HBc), and hepatitis B e antigen (HBeAg) and antibody to HBeAg (anti-HBe). At least one serologic marker is present during the different phases of HBV infection.
Case Definition for Influenza A (H1N1) Virus Infection (Swine Flu)
After identification of novel influenza A (H1N1) virus infection in Mexico, a case definition was developed. The initial definition of suspected novel influenza A (H1N1) virus infection included any hospitalized patient with severe acute respiratory illness. On May 1, 2009, this definition was expanded to include any person with acute respiratory illness defined as fever and either sore throat or cough. On May 11, 2009, the definition of suspected case was changed again to include any person with:
Rochester Criteria for Identifying Febrile Infants at Low Risk for Serious Bacterial Infection
The Rochester criteria were developed to identify febrile infants aged 60 days or younger at low-risk of bacterial infection and do not include cerebrospinal fluid (CSF) testing.
Unexplained Fever in Young Children
Clinical and laboratory “low risk” criteria for children younger than 3 months with fever and no focus of infection
Clinical criteria
- Born at term (gestational age >/= 37 weeks)with uncomplicated nursery stay
- Previously healthy infants
- Notoxic manifestations
- No focal bacterial infection (except otitis media)
1993 Revised Classification System for HIV Infection and Expanded AIDS Surveillance Case Definition for Adolescents and Adults
CDC has revised the classification system for HIV infection to emphasize the clinical importance of the CD4+ T-lymphocyte count in the categorization of HIV-related clinical conditions.