Bacterial Meningitis; The African Scourge

in StemSocial4 years ago (edited)

Hello Hivers!
In today's article, I'll explore meningitis. I have seen a lot of cases personally in the clinic and have part of the management team of some. Meningitis exerts a heavy burden on health care in Sub-Saharan Africa.


Meningitis is observed worldwide but the highest burden of the disease is in the meningitis belt of sub-Saharan Africa, stretching from Senegal in the west to Ethiopia in the east. Around 30,000 cases are still reported each year from that area.

Meningitis
Neck stiffness, Texas meningitis epidemic of 1911–12. By L.A. Marty, M.D, Kansas City - Sophian, Abraham: Epidemic cerebrospinal meningitis (1913), St. Louis, C.V Mosby (Scan from archive.org)., Public Domain, Link



Bacterial Meningitis

Several different bacteria can cause meningitis but Neisseria meningitidis is the one with the potential to cause large epidemics. There are 12 serogroups of N. meningitidis that have been identified, 6 of which (A, B, C, W, X and Y) can cause epidemics. Geographic distribution and epidemic potential differ according to serogroup.
  • The highest incidence is among neonates, who are usually infected by bacteria found in the birth canal at the time of parturition. Group B streptococci (Streptococcus agalactiae) account for the majority of cases; other causes include Listeria monocytogenes, E.coli, other Gram-negative bacilli, and enterococci.

  • From age 1 to 23 months, the most common organisms are Streptococcus pneumoniae and Neisseria meningitidis

  • Children from the 2 - 5 years used to have a high rate of infection caused by Haemophilus influenzae type b. However the wide use of protein-polysaccharide conjugated vaccines has dramatically reduced the incidence of this infection.

  • From age 2 through 18, N. meningitidis is the most common cause, accounting for more than 1/2 of cases, followed by S. pneumoniae

  • In adults up to age 60, S. pneumoniae is most common followed by N. meningitis.

  • Over age 60, most cases are due to S. pneumoniae and less often L. monocytogenes



Epidemiology

The African meningitis belt is a region in sub-Saharan Africa where the rate of incidence of meningitis is very high. It stretches from Senegal in the west to Ethiopia in the east (26 countries). The risk of meningococcal meningitis epidemics differs within and among these 26 countries.
Meningitis Belt The meningitis belt, showing the distribution of meningococcal meningitis in Africa. By Ninjatacoshell - Own work, derived from File:BlankMap-Africa.svg, CC BY-SA 3.0, Link

The Meningitis Belt is geographically situated between latitude 10° and 15° North.

In the meningitis belt, serogroup A has historically accounted for 90% of meningococcal disease cases and the majority of large-scale epidemics. In the past, Nigeria has suffered large-scale outbreaks of meningitis A. In 2009, such an outbreak in the country caused over 55,000 cases with close to 2,500 deaths.


image.png
Source: Nigeria Center for Disease Control


In Europe, the Americas, and Australia, serogroups B, C, and Y together account for a large majority of cases. Increasing numbers of serogroup W have been observed in some areas. In temperate regions the number of cases increases in winter and spring.

The epidemics usually start in the beginning of the dry season and end quickly when the rains start, only to break out again when the subsequent dry season starts. Other factors associated with the epidemics are absolute humidity, increased dust concentration and higher number of respiratory tract infections due to the cold nights.

The rates of meningococcal disease are highest in young children because of their reduction of protective maternal antibodies and then increasing again for adolescents and young adults


Vaccines

There are vaccines available for the prevention of Meningitis. There are different vaccines against the different organism which cause Meningitis as we discussed earlier.

There are vaccines against Haemophilus influenzae type b (Hib) and against some strains of N. meningitidis and many types of Streptococcus pneumoniae.

The vaccine against haemophilus influenze (Hib) has reduced Hib meningitis cases by 95 percent since 1985. There are vaccines to prevent meningitis due to S. pneumoniae.

The pneumococcal polysaccharide vaccine is recommended for all persons over 65 years of age and younger persons at least 2 years old with certain chronic medical problems.

Meningococcal vaccines are active against many strains of N. meningitidis. The majority of meningococcal infections in Nigeria was caused by type B meningococcus. The present menigitis C epidemic is not new and a vaccine is available.


Conclusion

In conclusion, Bacterial meningitis in adults occurs in a number of clinical situations. Majority (80-85%) are caused by N. meningitides and Strep pneumoniae. The classical triad of headache, fever and neck pain may not be present. High index of suspicion is needed. Speed is of essence in investigation and treatment. The incidence of bacterial meningitis can be greatly reduced by vaccination and chemoprophylaxis.


REFERENCES




Written by @gamsam - a Medical Student
All images used are copyright free
Vancouver Style was used for References.


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 4 years ago  

Is the pathogen of this disease what they refer to as 'brain-eating' bacterium? I think I've heard something like that before. That's quite some prevalence statistics, unfortunately, I am not sure I have physically come across any case in reality. Nice effort!

Thanks a lot.
I think you're referring to either the "flesh eating bacteria" or the "brain eating amoeba".
They are both different from this though. I am actually going to be making a post about the flesh eating bacteria very soon.

 4 years ago  

It is unfortunate that the rate of this pathology is so great, but that is due to the conoditions of life. Very well detailed all this pathology, sincerely enjoy reading it. Thank you for this!

Yeah, very true
Thanks a lot. Glad you enjoyed reading it.

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This is a well detailed piece on meningitis. Thanks also for putting out the preventive measures against meningitis.

Reducing handshaking, kissing

I didn't know that these practices can remotely predispose one to meningitis.

Thanks for sharing

Thanks for stopping by.
They do not directly predispose one to meningitis, but in a way they can generally reduce our exposure to foreign microbes that can cause meningitis.