What are the virulence factors of Streptococcus?
Virulence factors of group A streptococci include (1) M protein and lipoteichoic acid for attachment; (2) a hyaluronic acid capsule that inhibits phagocytosis; (3) other extracellular products, such as pyrogenic (erythrogenic) toxin, which causes the rash of scarlet fever; and (4) streptokinase, streptodornase (DNase B …
What are the virulence factors for Ebola?
The current hypothesis is that the fundamental mechanism of Ebola virus pathogenesis is vascular injury and damage secondary to coagulation abnormalities and increased vascular permeability, due to the release of inflammatory cytokines and chemokines by infected and activated monocytes and macrophages, and to direct …
What are the main virulence factors of Streptococcus pyogenes?
GAS strains express many virulence factors including surface protein M, streptolysins, streptokinase, hyaluronidase, peptidoglycan, and teichoic acid. Protein M is considered as the main virulence factor, limiting phagocytosis, disturbing the function of complement, and being responsible for adhesion [4].
What are the virulence factors of Streptococcus agalactiae?
Table 1
| Virulence factor | Mode of action | Genetic basis |
|---|---|---|
| Sialic acid capsular polysaccharide (CPS) | Prevents recognition of GBS through molecular mimicry of host-cell surface glycoconjugates | cpsA–L, neuA–D |
| Masks pro-inflammatory cell wall components | ||
| Superoxide dismutase (SodA) | Detoxifies singlet oxygen and superoxide | soda |
What kind of disease does the Ebola virus cause?
Ebola virus (EBOV) is a member of the filoviridae family that causes severe hemorrhagic fever during sporadic outbreaks, and no approved treatments are currently available. The multifunctional EBOV VP35 protein facilitates immune evasion by antagonizing antiviral signaling pathways and is important …
Is the Ebola virus a natural reservoir for humans?
The various species of Ebola virus sporadically infect both human and non-human primates, causing Ebola Hemorrhagic Fever. Recent evidence suggests that the virus may have a natural reservoir in various bat populations.
How did Ebola get into the human population?
Ebola is introduced into the human population through close contact with the blood, secretions, organs or other bodily fluids of infected animals such as fruit bats, chimpanzees, gorillas, monkeys, forest antelope or porcupines found ill or dead or in the rainforest.
How is the virulence of a pathogen measured?
Virulence is typically defined as morbidity and mortality of the host organism as a result of parasite or pathogen activity. Measurements of a pathogen’s virulence are traditionally given in terms of parasite induced death rate (PIHD).