Antigenic Shift and Drift

Antigenic Drift Nature of antigenic variation: Minor Mechanism: Gradual accumulation of amino acid substitutions due to point mutation in the hemagglutinin (H) and neuraminidase (N) genes. As mutations accumulate, antibodies generated by exposure to previous strains do not neutralize current strains to the same extent,… Read More

Rickettsial Diseases Made Easy

Important features of Rickettsia and Rickettsial Diseases Obligate intracellular parasites like Chlamydia – can survive only in host cells Cannot produce their own ATP, so they utilize the ATP of a host cell Gram negative coccobacillia, and short bacilli that grow strictly in eukaryotic cells… Read More