Neisseria Meningitidis

Question 1

What is neisseria meningitidis?

Answer 1

Neisseria meningitidis is an obligate human pathogen, which is a gram negative and it goes around as diplococcus

Question 2

What are the serogroups of Neisseria Meningitidis?

Answer 2

It can be acapsulate or capsulate, there are 12 capsular serogroups, 5 of which are important (A, B, C, Y, W135) as they are responsible for disease. It must have capsule to cause invasive disease, the genes for capsules can be turned on and off

Question 3

What are the major symptoms of invasive meningococcal disease (IMD)?

Answer 3

Flu-like illness, fever, headache, drowsiness, diarrhoea, vomiting, photophobia, rashes, confusion and neck pain/stiffness. These are very general symptoms and very difficult to identify and in babies.
Can be identifies using the glass test, where the rashes will not go away when glass is pressed against the skin.
Progress quickly and most severe is septicaemia 㱺 septic shock
Overall fatality and survivors result in amputation, brain damage, seizures and deafness

Question 4

Describe the risk factor of IMD?

Answer 4

22% of meningitis disease is associated with passive smoking, such as within close proximity to smoker in a closed environment.
Believed that many free radicals and the cells will have a stressed phenotype and this could mean the cells are more susceptible to colonisation, or N. meningitidis is able to get through the epithelial or cigarette smoke turns on the virulence factor of N. meningitidis, making them more invasive.

Question 5

How do you treat meningitis?

Answer 5

Benzyl pencillin

Amplicillin or amoxycillin

Question 6

Which strain is most common in Europe?

Answer 6

serogroup B is the most popular.

Question 7

Which strain is most common in Africa and Asia?

Answer 7

serogroup A is the most popular.

Question 8

When and where does the meningitis belt emerge? Which strain causes this?

Answer 8

Around 10-12 years, there is an epidemic associated with the dry seasons with 200,000cases and deaths. This is largely caused by A but W135 is a concern.
During the dry season, there is a lot of sand storm, the epithelial cells get damaged and therefore more likely that bacteria will infect it, but there is 0 evidence that this is the case.

Question 9

Which age group is mostly effect by IMD?

Answer 9

The diseases are primarily linked to under 4 years of age and also a small peak in the 15-19 years of age.
N. Meningitidis W135 is increasing across over all age groups and the cause is unknown.

Question 10

Describe successful and new vaccines to elicit protection against IMD?

Answer 10

Polysaccharide vaccine made with purified capsular polysaccharide (CPS) T-cell dependent and provide short-term protection with no immunological memory
Conjugate-polysaccharide vaccine made with CPS attached to a carrier protein e.g. tetanus toxoid or CRM-197. T cell independent & memory response
Serogroup B vaccine showed little or no response to CPS. The capsular structure is identical to sugars found on the NCAM therefore very hard to induce an immune response to
Outer Membrane Vesicle induce immune response that an individual gets is against PorA, major immunogen of OMVs. It offers strain specific protection, therefore very useful in single strain epidermic.
4CMenB has 3 components: factor H binding protein (fHbp), heparin binding proteins (NhbA) and outer membrane binding protein (NadA) got 88% coverage in the UK