Introduction to Shigella: Shigella are the cause of bacillary dystentery exclusively facultative intracellular pathogens in intestine of humans and other primates. Shigella are slender (1-3 × 0.5 µm in size) Gram-negative rods belonging to the family Enterobacteriaceae. They are non-motile bacterium, non–sporulating and non-capsule formers. The genus Shigella comprises four different species; S. dysenteriae, S.flexneri, […]

Selection of Stool Samples: Collection of Stool Samples: Principles of Proper Sample Collection Recommended Materials and Precautions Preservation of Stool Samples: Principle and Importance of Preservation Types of Preservatives and Their Uses: Schaudinn’s Fixative Advantages Disadvantages PVA (Polyvinyl Alcohol) Advantages Disadvantages MIF (Merthiolate-Iodine-Formalin) Advantages Disadvantages Diluted Formalin Advantages Disadvantage

Macroscopy of Clinical Specimens: Sputum Examination Stool Macroscopy Urine Examination Cerebrospinal fluid (CSF) Microscopic Examination: Sputum Microscopy Pus, ulcer and skin specimen microscopy  Before utilizing the swab to create gram smears, the culture media should be inoculated. Feces microscopy Urine microscopy Cerebrospinal Fluid (CSF) Microscopy Purulent or cloudy CSF Slightly cloudy or clear CSF Upper

General characteristics: Classification: Test Classical EL Tor Hemolysis -ve +ve VP Test -ve +ve Polymyxin sensitivity Sensitive Resistant Group IV phage susceptibility Susceptible Non-susceptible Chicken Erythrocyte agglutination -ve +ve Mode of transmission:  Infection is acquired by feco-oral route and by ingestion of improperly cooked shellfish. The incubation period ranges from few hours to 2-3 days.

Diagnosis of Vibrio cholerae Culture methods: Fig: Vibrio cholerae on TCBS Biochemical identification: Test V. cholerae KIA (Kligler’s Iron Agar)  K/A TSI (Triple Sugar Iron) A/A String + Oxidase + Gas from glucose – Sucrose + Lysine + Arginine – Ornithine + VP (Voges-Proskauer ) V Growth in 0% NaCl + Growth in 1% NaCl

Introduction to Caliciviridae Family: Caliciviridae is a family of viruses having positive-sense, single stranded RNA which is non-segmented. The family Caliciviridae consists of several genera, Lagovirus, Nebovirus, Norovirus, Sapovirus and Vesivirus. Members of Caliciviridae are significant causes of viral gastroenteritis in both humans and a variety of animals. The first human calicivirus is called Norovirus

Introduction of Rotavirus: Rotaviruses are responsible for significant gastrointestinal disease, primarily in children 5 years of age and the young of other mammalian species. By the age of five, almost all children worldwide suffer from rotavirus gastroenteritis; 1 in 5 visit a clinic, 1 in 65 are admitted to the hospital, and 1 in 293

Introduction of Human African Trypanosomiasis (HAT): Human African trypanosomiasis (HAT) is also known as African sleeping sickness. It is an infectious disease caused by an extracellular protozoan parasite belonging to the genus Trypanosoma, species brucei. Two subspecies of Trypanosoma brucei are pathogenic for humans are T. b. gambiense and T. b. rhodesiense. It is a

Introduction to Smallpox: The variola virus, which belongs to the orthopoxvirus family, is the cause of smallpox, an acute contagious illness.  It was among the deadliest illnesses that people had ever encountered.   The World Health Assembly approved a plan to eradicate smallpox worldwide in 1959.  After a worldwide vaccination campaign, it was deemed extinct in